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Electronic Code of Federal Regulations

e-CFR Data is current as of October 28, 2014

Title 47Chapter ISubchapter C → Part 73


Title 47: Telecommunication


PART 73—RADIO BROADCAST SERVICES


Contents

Subpart A—AM Broadcast Stations

§73.1   Scope.
§73.14   AM broadcast definitions.
§73.21   Classes of AM broadcast channels and stations.
§73.23   AM broadcast station applications affected by international agreements.
§73.24   Broadcast facilities; showing required.
§73.25   Clear channels; Class A, Class B and Class D stations.
§73.26   Regional channels; Class B and Class D stations.
§73.27   Local channels; Class C stations.
§73.28   Assignment of stations to channels.
§73.29   Class C stations on regional channels.
§73.30   Petition for authorization of an allotment in the 1605-1705 kHz band.
§73.31   Rounding of nominal power specified on applications.
§73.33   Antenna systems; showing required.
§73.35   Calculation of improvement factors.
§73.37   Applications for broadcast facilities, showing required.
§73.44   AM transmission system emission limitations.
§73.45   AM antenna systems.
§73.49   AM transmission system fencing requirements.
§73.51   Determining operating power.
§73.53   Requirements for authorization of antenna monitors.
§73.54   Antenna resistance and reactance measurements.
§73.57   Remote reading antenna and common point ammeters.
§73.58   Indicating instruments.
§73.61   AM directional antenna field strength measurements.
§73.62   Directional antenna system operation and tolerances.
§73.68   Sampling systems for antenna monitors.
§73.69   Antenna monitors.
§73.72   Operating during the experimental period.
§73.88   Blanketing interference.
§73.99   Presunrise service authorization (PSRA) and postsunset service authorization (PSSA).
§73.127   Use of multiplex transmission.
§73.128   AM stereophonic broadcasting.
§73.132   Territorial exclusivity.
§73.150   Directional antenna systems.
§73.151   Field strength measurements to establish performance of directional antennas.
§73.152   Modification of directional antenna data.
§73.153   Field strength measurements in support of applications or evidence at hearings.
§73.154   AM directional antenna partial proof of performance measurements.
§73.155   Periodic directional antenna performance recertification.
§73.157   Antenna testing during daytime.
§73.158   Directional antenna monitoring points.
§73.160   Vertical plane radiation characteristics, f(θ).
§73.182   Engineering standards of allocation.
§73.183   Groundwave signals.
§73.184   Groundwave field strength graphs.
§73.185   Computation of interfering signal.
§73.186   Establishment of effective field at one kilometer.
§73.187   Limitation on daytime radiation.
§73.189   Minimum antenna heights or field strength requirements.
§73.190   Engineering charts and related formulas.

Subpart B—FM Broadcast Stations

§73.201   Numerical designation of FM broadcast channels.
§73.202   Table of Allotments.
§73.203   Availability of channels.
§73.204   International agreements and other restrictions on use of channels.
§73.205   Zones.
§73.207   Minimum distance separation between stations.
§73.208   Reference points and distance computations.
§73.209   Protection from interference.
§73.210   Station classes.
§73.211   Power and antenna height requirements.
§73.212   Administrative changes in authorizations.
§73.213   Grandfathered short-spaced stations.
§73.215   Contour protection for short-spaced assignments.
§73.220   Restrictions on use of channels.
§73.232   Territorial exclusivity.
§73.239   Use of common antenna site.
§73.258   Indicating instruments.
§73.267   Determining operating power.
§73.277   Permissible transmissions.
§73.293   Use of FM multiplex subcarriers.
§73.295   FM subsidiary communications services.
§73.297   FM stereophonic sound broadcasting.
§73.310   FM technical definitions.
§73.311   Field strength contours.
§73.312   Topographic data.
§73.313   Prediction of coverage.
§73.314   Field strength measurements.
§73.315   FM transmitter location.
§73.316   FM antenna systems.
§73.317   FM transmission system requirements.
§73.318   FM blanketing interference.
§73.319   FM multiplex subcarrier technical standards.
§73.322   FM stereophonic sound transmission standards.
§73.333   Engineering charts.

Subpart C—Digital Audio Broadcasting

§73.401   Scope.
§73.402   Definitions.
§73.403   Digital audio broadcasting service requirements.
§73.404   Interim hybrid IBOC DAB operation.

Subpart D—Noncommercial Educational FM Broadcast Stations

§73.501   Channels available for assignment.
§73.503   Licensing requirements and service.
§73.504   Channel assignments in the Mexican border area.
§73.505   Zones.
§73.506   Classes of noncommercial educational FM stations and channels.
§73.507   Minimum distance separations between stations.
§73.508   Standards of good engineering practice.
§73.509   Prohibited overlap.
§73.510   Antenna systems.
§73.511   Power and antenna height requirements.
§73.512   Special procedures applicable to Class D noncommercial educational stations.
§73.513   Noncommercial educational FM stations operating on unreserved channels.
§73.514   Protection from interference.
§73.515   NCE FM transmitter location.
§73.525   TV Channel 6 protection.
§73.558   Indicating instruments.
§73.561   Operating schedule; time sharing.
§73.567   Determining operating power.
§73.593   Subsidiary communications services.
§73.597   FM stereophonic sound broadcasting.
§73.599   NCE-FM engineering charts.

Subpart E—Television Broadcast Stations

§73.601   Scope of subpart.
§73.602   Cross reference to rules in other parts.
§73.603   Numerical designation of television channels.
§73.606   Table of allotments.
§73.607   Availability of channels.
§73.609   Zones.
§73.610   Minimum distance separations between stations.
§73.611   Reference points and distance computations.
§73.612   Protection from interference.
§73.613   Protection of Class A TV stations.
§73.614   Power and antenna height requirements.
§73.615   Administrative changes in authorizations.
§73.616   Post-transition DTV station interference protection.
§73.621   Noncommercial educational TV stations.
§73.622   Digital television table of allotments.
§73.623   DTV applications and changes to DTV allotments.
§73.624   Digital television broadcast stations.
§73.625   DTV coverage of principal community and antenna system.
§73.626   DTV distributed transmission systems.
§73.635   Use of common antenna site.
§73.641   Subscription TV definitions.
§73.642   Subscription TV service.
§73.643   Subscription TV operating requirements.
§73.644   Subscription TV transmission systems.
§73.646   Telecommunications Service on the Vertical Blanking Interval and in the Visual Signal.
§73.653   Operation of TV aural and visual transmitters.
§73.658   Affiliation agreements and network program practices; territorial exclusivity in non-network program arrangements.
§§73.659-73.663   [Reserved]
§73.664   Determining operating power.
§73.665   Use of TV aural baseband subcarriers.
§73.667   TV subsidiary communications services.
§73.669   TV stereophonic aural and multiplex subcarrier operation.
§73.670   Commercial limits in children's programs.
§73.671   Educational and informational programming for children.
§73.672   [Reserved]
§73.673   Public information initiatives regarding educational and informational programming for children.
§73.674   Digital television transition notices by broadcasters.
§73.681   Definitions.
§73.682   TV transmission standards.
§73.683   Field strength contours and presumptive determination of field strength at individual locations.
§73.684   Prediction of coverage.
§73.685   Transmitter location and antenna system.
§73.686   Field strength measurements.
§73.687   Transmission system requirements.
§73.688   Indicating instruments.
§73.691   Visual modulation monitoring.
§73.698   Tables.
§73.699   TV engineering charts.

Subpart F—International Broadcast Stations

§73.701   Definitions.
§73.702   Assignment and use of frequencies.
§73.703   Geographical zones and areas of reception.
§73.712   Equipment tests.
§73.713   Program tests.
§73.731   Licensing requirements.
§73.732   Authorizations.
§73.733   Normal license period.
§73.751   Operating power.
§73.753   Antenna systems.
§73.754   Frequency monitors.
§73.755   Modulation monitors.
§73.756   System specifications for double-sideband (DBS) modulated emissions in the HF broadcasting service.
§73.757   System specifications for single-sideband (SSB) modulated emissions in the HF broadcasting service.
§73.758   System specifications for digitally modulated emissions in the HF broadcasting service.
§73.759   Auxiliary transmitters.
§73.760   Alternate main transmitters.
§73.761   Modification of transmission systems.
§73.762   Time of operation.
§73.765   Determining operating power.
§73.766   [Reserved]
§73.781   Logs.
§73.782   Retention of logs.
§73.787   Station identification.
§73.788   Service; commercial or sponsored programs.

Subpart G—Low Power FM Broadcast Stations (LPFM)

§73.801   Broadcast regulations applicable to LPFM stations.
§73.805   Availability of channels.
§73.807   Minimum distance separation between stations.
§73.808   Distance computations.
§73.809   Interference protection to full service FM stations.
§73.810   Third adjacent channel interference.
§73.811   LPFM power and antenna height requirements.
§73.812   Rounding of power and antenna heights.
§73.813   Determination of antenna height above average terrain (HAAT).
§73.816   Antennas.
§73.825   Protection to reception of TV channel 6.
§73.827   Interference to the input signals of FM translator or FM booster stations.
§73.840   Operating power and mode tolerances.
§73.845   Transmission system operation.
§73.850   Operating schedule.
§73.853   Licensing requirements and service.
§73.854   Unlicensed operations.
§73.855   Ownership limits.
§73.858   Attribution of LPFM station interests.
§73.860   Cross-ownership.
§73.865   Assignment and transfer of LPFM licenses.
§73.870   Processing of LPFM broadcast station applications.
§73.871   Amendment of LPFM broadcast station applications.
§73.872   Selection procedure for mutually exclusive LPFM applications.
§73.873   LPFM license period.
§73.875   Modification of transmission systems.
§73.877   Station logs for LPFM stations.
§73.878   Station inspections by FCC; availability to FCC of station logs and records.
§73.879   Signal retransmission.
§73.881   Equal employment opportunities.

Subpart H—Rules Applicable to All Broadcast Stations

§73.1001   Scope.
§73.1010   Cross reference to rules in other parts.
§73.1015   Truthful written statements and responses to Commission inquiries and correspondence.
§73.1020   Station license period.
§73.1030   Notifications concerning interference to radio astronomy, research and receiving installations.
§73.1120   Station location.
§73.1125   Station main studio location.
§73.1150   Transferring a station.
§73.1201   Station identification.
§73.1202   Retention of letters received from the public.
§73.1206   Broadcast of telephone conversations.
§73.1207   Rebroadcasts.
§73.1208   Broadcast of taped, filmed, or recorded material.
§73.1209   References to time.
§73.1210   TV/FM dual-language broadcasting in Puerto Rico.
§73.1211   Broadcast of lottery information.
§73.1212   Sponsorship identification; list retention; related requirements.
§73.1213   Antenna structure, marking and lighting.
§73.1215   Specifications for indicating instruments.
§73.1216   Licensee-conducted contests.
§73.1217   Broadcast hoaxes.
§73.1225   Station inspections by FCC.
§73.1226   Availability to FCC of station logs and records.
§73.1230   Posting of station license.
§73.1250   Broadcasting emergency information.
§73.1300   Unattended station operation.
§73.1350   Transmission system operation.
§73.1400   Transmission system monitoring and control.
§73.1515   Special field test authorizations.
§73.1520   Operation for tests and maintenance.
§73.1530   Portable test stations [Definition].
§73.1540   Carrier frequency measurements.
§73.1545   Carrier frequency departure tolerances.
§73.1560   Operating power and mode tolerances.
§73.1570   Modulation levels: AM, FM, TV and Class A TV aural.
§73.1580   Transmission system inspections.
§73.1590   Equipment performance measurements.
§73.1610   Equipment tests.
§73.1615   Operation during modification of facilities.
§73.1620   Program tests.
§73.1635   Special temporary authorizations (STA).
§73.1650   International agreements.
§73.1660   Acceptability of broadcast transmitters.
§73.1665   Main transmitters.
§73.1670   Auxiliary transmitters.
§73.1675   Auxiliary antennas.
§73.1680   Emergency antennas.
§73.1690   Modification of transmission systems.
§73.1692   [Reserved]
§73.1695   Changes in transmission standards.
§73.1700   Broadcast day.
§73.1705   Time of operation.
§73.1710   Unlimited time.
§73.1715   Share time.
§73.1720   Daytime.
§73.1725   Limited time.
§73.1730   Specified hours.
§73.1735   AM station operation pre-sunrise and post-sunset.
§73.1740   Minimum operating schedule.
§73.1745   Unauthorized operation.
§73.1750   Discontinuance of operation.
§73.1800   General requirements related to the station log.
§73.1820   Station log.
§73.1835   Special technical records.
§73.1840   Retention of logs.
§73.1870   Chief operators.
§73.1940   Legally qualified candidates for public office.
§73.1941   Equal opportunities.
§73.1942   Candidate rates.
§73.1943   Political file.
§73.1944   Reasonable access.
§73.2080   Equal employment opportunities (EEO).
§73.2090   Ban on discrimination in broadcast transactions.
§73.3500   Application and report forms.
§73.3511   Applications required.
§73.3512   Where to file; number of copies.
§73.3513   Signing of applications.
§73.3514   Content of applications.
§73.3516   Specification of facilities.
§73.3517   Contingent applications.
§73.3518   Inconsistent or conflicting applications.
§73.3519   Repetitious applications.
§73.3520   Multiple applications.
§73.3521   Mutually exclusive applications for low power television, television translators and television booster stations.
§73.3522   Amendment of applications.
§73.3523   Dismissal of applications in renewal proceedings.
§73.3525   Agreements for removing application conflicts.
§73.3526   Local public inspection file of commercial stations.
§73.3527   Local public inspection file of noncommercial educational stations.
§73.3533   Application for construction permit or modification of construction permit.
§73.3534   [Reserved]
§73.3536   Application for license to cover construction permit.
§73.3537   Application for license to use former main antenna as an auxiliary.
§73.3538   Application to make changes in an existing station.
§73.3539   Application for renewal of license.
§73.3540   Application for voluntary assignment or transfer of control.
§73.3541   Application for involuntary assignment of license or transfer of control.
§73.3542   Application for emergency authorization.
§73.3543   Application for renewal or modification of special service authorization.
§73.3544   Application to obtain a modified station license.
§73.3545   Application for permit to deliver programs to foreign stations.
§73.3549   Requests for extension of time to operate without required monitors, indicating instruments, and EAS encoders and decoders.
§73.3550   Requests for new or modified call sign assignments.
§73.3555   Multiple ownership.
§73.3556   Duplication of programming on commonly owned or time brokered stations.
§73.3561   Staff consideration of applications requiring Commission action.
§73.3562   Staff consideration of applications not requiring action by the Commission.
§73.3564   Acceptance of applications.
§73.3566   Defective applications.
§73.3568   Dismissal of applications.
§73.3571   Processing of AM broadcast station applications.
§73.3572   Processing of TV broadcast, Class A TV broadcast, low power TV, TV translators, and TV booster applications.
§73.3573   Processing FM broadcast station applications.
§73.3574   Processing of international broadcast station applications.
§73.3578   Amendments to applications for renewal, assignment or transfer of control.
§73.3580   Local public notice of filing of broadcast applications.
§73.3584   Procedure for filing petitions to deny.
§73.3587   Procedure for filing informal objections.
§73.3588   Dismissal of petitions to deny or withdrawal of informal objections.
§73.3589   Threats to file petitions to deny or informal objections.
§73.3591   Grants without hearing.
§73.3592   Conditional grant.
§73.3593   Designation for hearing.
§73.3594   Local public notice of designation for hearing.
§73.3597   Procedures on transfer and assignment applications.
§73.3598   Period of construction.
§73.3601   Simultaneous modification and renewal of license.
§73.3603   Special waiver procedure relative to applications.
§73.3605   Retention of applications in hearing status after designation for hearing.
§73.3612   Annual employment report.
§73.3613   Filing of contracts.
§73.3615   Ownership reports.
§73.3617   Information available on the Internet.
§73.3700   Post-incentive auction licensing and operation.
§73.3999   Enforcement of 18 U.S.C. 1464 (restrictions on the transmission of obscene and indecent material).
§73.4000   Listing of FCC policies.
§73.4005   Advertising—refusal to sell.
§73.4015   Applications for AM and FM construction permits, incomplete or defective.
§73.4017   Application processing: Commercial FM stations.
§73.4045   Barter agreements.
§73.4050   Children's TV programs.
§73.4055   Cigarette advertising.
§73.4060   Citizens agreements.
§73.4075   Commercials, loud.
§73.4082   Comparative broadcast hearings—specialized programming formats.
§73.4091   Direct broadcast satellites.
§73.4094   Dolby encoder.
§73.4095   Drug lyrics.
§73.4097   EBS (now EAS) attention signals on automated programing systems.
§73.4099   Financial qualifications, certification of.
§73.4100   Financial qualifications; new AM and FM stations.
§73.4101   Financial qualifications, TV stations.
§73.4102   FAA communications, broadcast of.
§73.4104   FM assignment policies and procedures.
§73.4107   FM broadcast assignments, increasing availability of.
§73.4108   FM transmitter site map submissions.
§73.4110   Format changes of stations.
§73.4135   Interference to TV reception by FM stations.
§73.4140   Minority ownership; tax certificates and distress sales.
§73.4154   Network/AM, FM station affiliation agreements.
§73.4157   Network signals which adversely affect affiliate broadcast service.
§73.4163   Noncommercial nature of educational broadcast stations.
§73.4165   Obscene language.
§73.4170   Obscene broadcasts.
§73.4180   Payment disclosure: Payola, plugola, kickbacks.
§73.4185   Political broadcasting and telecasting, the law of.
§73.4190   Political candidate authorization notice and sponsorship identification.
§73.4195   Political advertising by UHF translators.
§73.4210   Procedure Manual: “The Public and Broadcasting”.
§73.4215   Program matter: Supplier identification.
§73.4242   Sponsorship identification rules, applicability of.
§73.4246   Stereophonic pilot subcarrier use during monophonic programming.
§73.4247   STV: Competing applications.
§73.4250   Subliminal perception.
§73.4255   Tax certificates: Issuance of.
§73.4260   Teaser announcements.
§73.4265   Telephone conversation broadcasts (network and like sources).
§73.4266   Tender offer and proxy statements.
§73.4267   Time brokerage.
§73.4275   Tone clusters; audio attention-getting devices.
§73.4280   Character evaluation of broadcast applicants.

Subpart I—Procedures for Competitive Bidding and for Applications for Noncommercial Educational Broadcast Stations on Non-Reserved Channels

§73.5000   Services subject to competitive bidding.
§73.5001   [Reserved]
§73.5002   Application and certification procedures; return of mutually exclusive applications not subject to competitive bidding procedures; prohibition of collusion.
§73.5003   Submission of full payments.
§73.5004   [Reserved]
§73.5005   Filing of long-form applications.
§73.5006   Filing of petitions to deny against long-form applications.
§73.5007   Designated entity provisions.
§73.5008   Definitions applicable for designated entity provisions.
§73.5009   Assignment or transfer of control.

Subpart J—Class A Television Broadcast Stations

§73.6000   Definitions.
§73.6001   Eligibility and service requirements.
§73.6002   Licensing requirements.
§§73.6003-73.6005   [Reserved]
§73.6006   Channel assignments.
§73.6007   Power limitations.
§73.6008   Distance computations.
§73.6010   Class A TV station protected contour.
§73.6011   Protection of TV broadcast stations.
§73.6012   Protection of Class A TV, low power TV and TV translator stations.
§73.6013   Protection of DTV stations.
§73.6014   Protection of digital Class A TV stations.
§73.6016   Digital Class A TV station protection of TV broadcast stations.
§73.6017   Digital Class A TV station protection of Class A TV and digital Class A TV stations.
§73.6018   Digital Class A TV station protection of DTV stations.
§73.6019   Digital Class A TV station protection of low power TV, TV translator, digital low power TV and digital TV translator stations.
§73.6020   Protection of stations in the land mobile radio service.
§73.6022   Negotiated interference and relocation agreements.
§73.6023   Distributed transmission systems.
§73.6024   Transmission standards and system requirements.
§73.6025   Antenna system and station location.
§73.6026   Broadcast regulations applicable to Class A television stations.
§73.6027   Class A TV notifications concerning interference to radio astronomy, research and receiving installations.

Subpart K—Application and Selection Procedures for Reserved Noncommercial Educational Channels, and for Certain Applications for Noncommercial Educational Stations on Non-Reserved Channels

§73.7000   Definition of terms (as used in subpart K only).
§73.7001   Services subject to evaluation by point system.
§73.7002   Fair distribution of service on reserved band FM channels.
§73.7003   Point system selection procedures.
§73.7004   Petitions to deny tentative selectee(s).
§73.7005   Holding period.

Subpart L—Incorporated Standards

§73.8000   Incorporation by reference.
Alphabetical Index—Part 73

Authority: 47 U.S.C. 154, 303, 334, 336, and 339.

Subpart A—AM Broadcast Stations

§73.1   Scope.

This subpart contains those rules which apply exclusively to the AM broadcast service and are in addition to those rules in Subpart H which are common to all AM, FM and TV broadcast services, commercial and noncommercial.

[47 FR 8587, Mar. 1, 1982]

§73.14   AM broadcast definitions.

AM broadcast band. The band of frequencies extending from 535 to 1705 kHz.

AM broadcast channel. The band of frequencies occupied by the carrier and the upper and lower sidebands of an AM broadcast signal with the carrier frequency at the center. Channels are designated by their assigned carrier frequencies. The 117 carrier frequencies assigned to AM broadcast stations begin at 540 kHz and progress in 10 kHz steps to 1700 kHz. (See §73.21 for the classification of AM broadcast channels).

AM broadcast station. A broadcast station licensed for the dissemination of radio communications intended to be received by the public and operated on a channel in the AM broadcast band.

Amplitude modulated stage. The radio-frequency stage to which the modulator is coupled and in which the carrier wave is modulated in accordance with the system of amplitude modulation and the characteristics of the modulating wave.

Amplitude modulator stage. The last amplifier stage of the modulating wave amplitude modulates a radio-frequency stage.

Antenna current. The radio-frequency current in the antenna with no modulation.

Antenna input power. The product of the square of the antenna current and the antenna resistance at the point where the current is measured.

Antenna resistance. The total resistance of the transmitting antenna system at the operating frequency and at the point at which the antenna current is measured.

Auxiliary facility. An auxiliary facility is an AM antenna tower(s) separate from the main facility's antenna tower(s), permanently installed at the same site or at a different location, from which an AM station may broadcast for short periods without prior Commission authorization or notice to the Commission while the main facility is not in operation (e.g., where tower work necessitates turning off the main antenna or where lightning has caused damage to the main antenna or transmission system) (See §73.1675).

Blanketing. The interference which is caused by the presence of an AM broadcast signal of one volt per meter (V/m) or greater strengths in the area adjacent to the antenna of the transmitting station. The 1 V/m contour is referred to as the blanket contour and the area within this contour is referred to as the blanket area.

Carrier-amplitude regulation (Carrier shift). The change in amplitude of the carrier wave in an amplitude-modulated transmitter when modulation is applied under conditions of symmetrical modulation.

Combined audio harmonics. The arithmetical sum of the amplitudes of all the separate harmonic components. Root sum square harmonic readings may be accepted under conditions prescribed by the FCC.

Critical hours. The two hour period immediately following local sunrise and the two hour period immediately preceding local sunset.

Daytime. The period of time between local sunrise and local sunset.

Effective field; Effective field strength. The root-mean-square (RMS) value of the inverse distance fields at a distance of 1 kilometer from the antenna in all directions in the horizontal plane. The term “field strength” is synonymous with the term “field intensity” as contained elsewhere in this Part.

Equipment performance measurements. The measurements performed to determine the overall performance characteristics of a broadcast transmission system from point of program origination at main studio to sampling of signal as radiated. (See §73.1590)

Experimental period. the time between 12 midnight local time and local sunrise, used by AM stations for tests, maintenance and experimentation.

Frequency departure. The amount of variation of a carrier frequency or center frequency from its assigned value.

Incidental phase modulation. The peak phase deviation (in radians) resulting from the process of amplitude modulation.

Input power. Means the product of the direct voltage applied to the last radio stage and the total direct current flowing to the last radio stage, measured without modulation.

Intermittent service area. Means the area receiving service from the groundwave of a broadcast station but beyond the primary service area and subject to some interference and fading.

Last radio stage. The radio-frequency power amplifier stage which supplies power to the antenna.

Left (or right) signal. The electrical output of a microphone or combination of microphones placed so as to convey the intensity, time, and location of sounds originated predominately to the listener's left (or right) of the center of the performing area.

Left (or right) stereophonic channel. The left (or right) signal as electrically reproduced in reception of AM stereophonic broadcasts.

Main channel. The band of audio frequencies from 50 to 10,000 Hz which amplitude modulates the carrier.

Maximum percentage of modulation. The greatest percentage of modulation that may be obtained by a transmitter without producing in its output, harmonics of the modulating frequency in excess of those permitted by these regulations. (See §73.1570)

Maximum rated carrier power. The maximum power at which the transmitter can be operated satisfactorily and is determined by the design of the transmitter and the type and number of vacuum tubes or other amplifier devices used in the last radio stage.

Model I facility. A station operating in the 1605-1705 kHz band featuring fulltime operation with stereo, competitive technical quality, 10 kW daytime power, 1 kW nighttime power, non-directional antenna (or a simple directional antenna system), and separated by 400-800 km from other co-channel stations.

Model II facility. A station operating in the 535-1605 kHz band featuring fulltime operation, competitive technical quality, wide area daytime coverage with nighttime coverage at least 15% of the daytime coverage.

Nighttime. The period of time between local sunset and local sunrise.

Nominal power. The antenna input power less any power loss through a dissipative network and, for directional antennas, without consideration of adjustments specified in paragraphs (b)(1) and (b)(2) of §73.51 of the rules. However, for AM broadcast applications granted or filed before June 3, 1985, nominal power is specified in a system of classifications which include the following values: 50 kW, 25 kW, 10 kW, 5 kW, 2.5 kW, 1 kW, 0.5 kW, and 0.25 kW. The specified nominal power for any station in this group of stations will be retained until action is taken on or after June 3, 1985, which involves a change in the technical facilities of the station.

Percentage modulation (amplitude)

In a positive direction:

M = MAX−C × 100

         ————--—--—

               c

In a negative direction:

M = C−MIN × 100

         ————-—--—

               c

Where:

M = Modulation level in percent.

MAX = Instantaneous maximum level of the modulated radio frequency envelope.

MIN = Instantaneous minimum level of the modulated radio frequency envelope.

C = (Carrier) level of radio frequency envelope without modulation.

Plate modulation. The modulation produced by introduction of the modulating wave into the plate circuit of any tube in which the carrier frequency wave is present.

Primary service area. Means the service area of a broadcast station in which the groundwave is not subject to objectionable interference or objectionable fading.

Proof of performance measurements or antenna proof of performance measurements. The measurements of field strengths made to determine the radiation pattern or characteristics of an AM directional antenna system.

Secondary service area. Means the service area of a broadcast station served by the skywave and not subject to objectionable interference and in which the signal is subject to intermittent variations in strength.

Stereophonic channel. The band of audio frequencies from 50 to 10,000 Hz containing the stereophonic information which modulates the radio frequency carrier.

Stereophonic crosstalk. An undesired signal occurring in the main channel from modulation of the stereophonic channel or that occurring in the stereophonic channel from modulation of the main channel.

Stereophonic pilot tone. An audio tone of fixed or variable frequency modulating the carrier during the transmission of stereophonic programs.

Stereophonic separation. The ratio of the electrical signal caused in the right (or left) stereophonic channel to the electrical signal caused in the left (or right) stereophonic channel by the transmission of only a right (or left) signal.

Sunrise and sunset. For each particular location and during any particular month, the time of sunrise and sunset as specified in the instrument of authorization (See §73.1209).

White area. The area or population which does not receive interference-free primary service from an authorized AM station or does not receive a signal strength of at least 1 mV/m from an authorized FM station.

[47 FR 8587, Mar. 1, 1982, as amended at 47 FR 13164, Mar. 29, 1982; 47 FR 13812, Apr. 1, 1982; 50 FR 18821, May 2, 1985; 50 FR 47054, Nov. 14, 1985; 56 FR 64856, Dec. 12, 1991; 62 FR 51058, Sept. 30, 1997; 66 FR 20755, Apr. 25, 2001]

§73.21   Classes of AM broadcast channels and stations.

(a) Clear channel. A clear channel is one on which stations are assigned to serve wide areas. These stations are protected from objectionable interference within their primary service areas and, depending on the class of station, their secondary service areas. Stations operating on these channels are classified as follows:

(1) Class A station. A Class A station is an unlimited time station that operates on a clear channel and is designed to render primary and secondary service over an extended area and at relatively long distances from its transmitter. Its primary service area is protected from objectionable interference from other stations on the same and adjacent channels, and its secondary service area is protected from interference from other stations on the same channel. (See §73.182). The operating power shall not be less than 10 kW nor more than 50 kW. (Also see §73.25(a)).

(2) Class B station. A Class B station is an unlimited time station which is designed to render service only over a primary service area. Class B stations are authorized to operate with a minimum power of 0.25 kW (or, if less than 0.25 kW, an equivalent RMS antenna field of at least 141 mV/m at 1 km) and a maximum power of 50 kW, or 10 kW for stations that are authorized to operate in the 1605-1705 kHz band.

(3) Class D station. A Class D station operates either daytime, limited time or unlimited time with nighttime power less than 0.25 kW and an equivalent RMS antenna field of less than 141 mV/m at one km. Class D stations shall operate with daytime powers not less than 0.25 kW nor more than 50 kW. Nighttime operations of Class D stations are not afforded protection and must protect all Class A and Class B operations during nighttime hours. New Class D stations that had not been previously licensed as Class B will not be authorized.

(b) Regional Channel. A regional channel is one on which Class B and Class D stations may operate and serve primarily a principal center of population and the rural area contiguous thereto.

Note: Until the North American Regional Broadcasting Agreement (NARBA) is terminated with respect to the Bahama Islands and the Dominican Republic, radiation toward those countries from a Class B station may not exceed the level that would be produced by an omnidirectional antenna with a transmitted power of 5 kW, or such lower level as will comply with NARBA requirements for protection of stations in the Bahama Islands and the Dominican Republic against objectionable interference.

(c) Local channel. A local channel is one on which stations operate unlimited time and serve primarily a community and the suburban and rural areas immediately contiguous thereto.

(1) Class C station. A Class C station is a station operating on a local channel and is designed to render service only over a primary service area that may be reduced as a consequence of interference in accordance with §73.182. The power shall not be less than 0.25 kW, nor more than 1 kW. Class C stations that are licensed to operate with 0.1 kW may continue to do so.

[56 FR 64856, Dec. 12, 1991]

§73.23   AM broadcast station applications affected by international agreements.

(a) Except as provided in paragraph (b) of this section, no application for an AM station will be accepted for filing if authorization of the facilities requested would be inconsistent with international commitments of the United States under treaties and other international agreements, arrangements and understandings. (See list of such international instruments in §73.1650(b)). Any such application that is inadvertently accepted for filing will be dismissed.

(b) AM applications that involve conflicts only with the North American Regional Broadcasting Agreement (NARBA), but that are in conformity with the remaining treaties and other international agreements listed in §73.1650(b) and with the other requirements of this part 73, will be granted subject to such modifications as the FCC may subsequently find appropriate, taking international considerations into account.

(c) In the case of any application designated for hearing on issues other than those related to consistency with international relationships and as to which no final decision has been rendered, whenever action under this section becomes appropriate because of inconsistency with international relationships, the applicant involved shall, notwithstanding the provisions §§73.3522 and 73.3571, be permitted to amend its application to achieve consistency with such relationships. In such cases the provisions of §73.3605(c) will apply.

(d) In some circumstances, special international considerations may require that the FCC, in acting on applications, follow procedures different from those established for general use. In such cases, affected applicants will be informed of the procedures to be followed.

[56 FR 64856, Dec. 12, 1991]

§73.24   Broadcast facilities; showing required.

An authorization for a new AM broadcast station or increase in facilities of an existing station will be issued only after a satisfactory showing has been made in regard to the following, among others:

(a) That the proposed assignment will tend to effect a fair, efficient, and equitable distribution of radio service among the several states and communities.

(b) That a proposed new station (or a proposed change in the facilities of an authorized station) complies with the pertinent requirements of §73.37 of this chapter.

(c) That the applicant is financially qualified to construct and operate the proposed station.

(d) That the applicant is legally qualified. That the applicant (or the person or persons in control of an applicant corporation or other organization) is of good character and possesses other qualifications sufficient to provide a satisfactory public service.

(e) That the technical equipment proposed, the location of the transmitter, and other technical phases of operation comply with the regulations governing the same, and the requirements of good engineering practice.

(f) That the facilities sought are subject to assignment as requested under existing international agreements and the rules and regulations of the Commission.

(g) That the population within the 1 V/m contour does not exceed 1.0 percent of the population within the 25 mV/m contour: Provided, however, That where the number of persons within the 1 V/m contour is 300 or less the provisions of this paragraph are not applicable.

(h) That, in the case of an application for a Class B or Class D station on a clear channel, the proposed station would radiate, during two hours following local sunrise and two hours preceding local sunset, in any direction toward the 0.1 mV/m groundwave contour of a co-channel United States Class A station, no more than the maximum value permitted under the provisions of §73.187.

(i) That, for all stations, the daytime 5 mV/m contour encompasses the entire principal community to be served. That, for stations in the 535-1605 kHz band, 80% of the principal community is encompassed by the nighttime 5 mV/m contour or the nighttime interference-free contour, whichever value is higher. That, for stations in the 1605-1705 kHz band, 50% of the principal community is encompassed by the 5 mV/m contour or the nighttime interference-free contour, whichever value is higher. That, Class D stations with nighttime authorizations need not demonstrate such coverage during nighttime operation.

(j) That the public interest, convenience, and necessity will be served through the operation under the proposed assignment.

[28 FR 13574, Dec. 14, 1963, as amended at 38 FR 5874, Mar. 5, 1973; 49 FR 43960, Nov. 1, 1984; 50 FR 40014, Oct. 1, 1985; 52 FR 11654, Apr. 10, 1987; 53 FR 1031, Jan. 15, 1988; 56 FR 64857, Dec. 12, 1991]

§73.25   Clear channels; Class A, Class B and Class D stations.

The frequencies in the following tabulations are designated as clear channels and assigned for use by the Classes of stations given:

(a) On each of the following channels, one Class A station may be assigned, operating with power of 50 kW: 640, 650, 660, 670, 700, 720, 750, 760, 770, 780, 820, 830, 840, 870, 880, 890, 1020, 1030, 1040, 1100, 1120, 1160, 1180, 1200, and 1210 kHz. In Alaska, these frequencies can be used by Class A stations subject to the conditions set forth in §73.182(a)(1)(ii). On the channels listed in this paragraph, Class B and Class D stations may be assigned.

(b) To each of the following channels there may be assigned Class A, Class B and Class D stations: 680, 710, 810, 850, 940, 1000, 1060, 1070, 1080, 1090, 1110, 1130, 1140, 1170, 1190, 1500, 1510, 1520, 1530, 1540, 1550, and 1560 kHz.

Note: Until superseded by a new agreement, protection of the Bahama Islands shall be in accordance with NARBA. Accordingly, a Class A, Class B or Class D station on 1540 kHz shall restrict its signal to a value no greater than 5 µV/m groundwave or 25 µV/m-10% skywave at any point of land in the Bahama Islands, and such stations operating nighttime (i.e., sunset to sunrise at the location of the U.S. station) shall be located not less than 650 miles from the nearest point of land in the Bahama Islands.

(c) Class A, Class B and Class D stations may be assigned on 540, 690, 730, 740, 800, 860, 900, 990, 1010, 1050, 1220, 1540, 1570, and 1580 kHz.

[28 FR 13574, Dec. 14, 1963, as amended at 33 FR 4410, Mar. 12, 1968; 35 FR 18052, Nov. 25, 1970; 47 FR 27862, June 28, 1982; 49 FR 43960, Nov. 1, 1984; 50 FR 24520, June 11, 1985; 52 FR 47568, Dec. 15, 1987; 53 FR 1031, Jan. 15, 1988; 54 FR 39736, Sept. 28, 1989; 56 FR 64857, Dec. 12, 1991]

§73.26   Regional channels; Class B and Class D stations.

(a) The following frequencies are designated as regional channels and are assigned for use by Class B and Class D stations: 550, 560, 570, 580, 590, 600, 610, 620, 630, 790, 910, 920, 930, 950, 960, 970, 980, 1150, 1250, 1260, 1270, 1280, 1290, 1300, 1310, 1320, 1330, 1350, 1360, 1370, 1380, 1390, 1410, 1420, 1430, 1440, 1460, 1470, 1480, 1590, 1600, 1610, 1620, 1630, 1640, 1650, 1660, 1670, 1680, 1690, and 1700 kHz.

(b) Additionally, in Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands the frequencies 1230, 1240, 1340, 1400, 1450, and 1490 kHz are designated as Regional channels, and are assigned for use by Class B stations. Stations formerly licensed to these channels in those locations as Class C stations are redesignated as Class B stations.

[56 FR 64857, Dec. 12, 1991]

§73.27   Local channels; Class C stations.

Within the conterminous 48 states, the following frequencies are designated as local channels, and are assigned for use by Class C stations: 1230, 1240, 1340, 1400, 1450, and 1490 kHz.

[56 FR 64857, Dec. 12, 1991]

§73.28   Assignment of stations to channels.

(a) The Commission will not make an AM station assignment that does not conform with international requirements and restrictions on spectrum use that the United States has accepted as a signatory to treaties, conventions, and other international agreements. See §73.1650 for a list of pertinent treaties, conventions and agreements, and §73.23 for procedural provisions relating to compliance with them.

(b) Engineering standards now in force domestically differ in some respects from those specified for international purposes. The engineering standards specified for international purposes (see §73.1650, International Agreements) will be used to determine:

(1) The extent to which interference might be caused by a proposed station in the United States to a station in another country; and

(2) whether the United States should register an objection to any new or changed assignment notified by another country. The domestic standards in effect in the United States will be used to determine the extent to which interference exists or would exist from a foreign station where the value of such interference enters into a calculation of:

(i) The service to be rendered by a proposed operation in the United States; or

(ii) the permissible interfering signal from one station in the United States to another United States station.

[28 FR 13574, Dec. 14, 1963, as amended at 29 FR 9499, July 11, 1964; 49 FR 32358, Aug. 14, 1984; 50 FR 18821, May 2, 1985; 54 FR 39736, Sept. 28, 1989; 56 FR 64857, Dec. 12, 1991]

§73.29   Class C stations on regional channels.

No license will be granted for the operation of a Class C station on a regional channel.

[ 56 FR 64857, Dec. 12, 1991]

§73.30   Petition for authorization of an allotment in the 1605-1705 kHz band.

(a) Any party interested in operating an AM broadcast station on one of the ten channels in the 1605-1705 kHz band must file a petition for the establishment of an allotment to its community of license. Each petition must include the following information:

(1) Name of community for which allotment is sought;

(2) Frequency and call letters of the petitioner's existing AM operation; and

(3) Statement as to whether or not AM stereo operation is proposed for the operation in the 1605-1705 kHz band.

(b) Petitions are to be filed during a filing period to be determined by the Commission. For each filing period, eligible stations will be allotted channels based on the following steps:

(1) Stations are ranked in descending order according to the calculated improvement factor.

(2) The station with the highest improvement factor is initially allotted the lowest available channel.

(3) Successively, each station with the next lowest improvement factor, is allotted an available channel taking into account the possible frequency and location combinations and relationship to previously selected allotments. If a channel is not available for the subject station, previous allotments are examined with respect to an alternate channel, the use of which would make a channel available for the subject station.

(4) When it has been determined that, in accordance with the above steps, no channel is available for the subject station, that station is no longer considered and the process continues to the station with the next lowest improvement factor.

(c) If awarded an allotment, a petitioner will have sixty (60) days from the date of public notice of selection to file an application for construction permit on FCC Form 301. (See §§73.24 and 73.37(e) for filing requirements). Unless instructed by the Commission to do otherwise, the application shall specify Model I facilities. (See §73.14). Upon grant of the application and subsequent construction of the authorized facility, the applicant must file a license application on FCC Form 302.

Note 1: Until further notice by the Commission, the filing of these petitions is limited to licensees of existing AM stations (excluding Class C stations) operating in the 535-1605 kHz band. First priority will be assigned to Class D stations located within the primary service contours of U.S. Class A stations that are licensed to serve communities of 100,000 or more for which there exists no local fulltime aural service.

Note 2: Selection among competing petitions will be based on interference reduction. Notwithstanding the exception contained in Note 5 of this section, within each operational category, the station demonstrating the highest value of improvement factor will be afforded the highest priority for an allotment, with the next priority assigned to the station with next lowest value, and so on, until available allotments are filled.

Note 3: The Commission will periodically evaluate the progress of the movement of stations from the 535-1605 kHz band to the 1605-1705 kHz band to determine whether the 1605-1705 kHz band should continue to be administered on an allotment basis or modified to an assignment method. If appropriate, the Commission will later develop further procedures for use of the 1605-1705 kHz band by existing station licensees and others.

Note 4: Other than the exception specified in note 1 of this section, existing fulltime stations are considered first for selection as described in note 2 of this section. In the event that an allotment availability exists for which no fulltime station has filed a relevant petition, such allotment may be awarded to a licensed Class D station. If more than one Class D station applies for this migration opportunity, the following priorities will be used in the selection process: First priority—a Class D station located within the 0.5 mV/m-50% contour of a U.S. Class A station and licensed to serve a community of 100,000 or more, for which there exists no local fulltime aural service; Second priority—Class D stations ranked in order of improvement factor, from highest to lowest, considering only those stations with improvement factors greater than zero.

Note 5: The preference for AM stereo in the expanded band will be administered as follows: when an allotment under consideration (candidate allotment) conflicts with one or more previously selected allotments (established allotments) and cannot be accommodated in the expanded band, the candidate allotment will be substituted for the previously established allotment provided that: the petitioner for the candidate allotment has made a written commitment to the use of AM stereo and the petitioner for the established allotment has not; the difference between the ranking factors associated with the candidate and established allotments does not exceed 10% of the ranking factor of the candidate allotment; the substitution will not require the displacement of more than one established allotment; and both the candidate allotment and the established allotment are within the same priority group.

[58 FR 27949, May 12, 1993]

§73.31   Rounding of nominal power specified on applications.

(a) An application filed with the FCC for a new station or for an increase in power of an existing station shall specify nominal power rounded to two significant figures as follows:

Nominal power (kW)Rounded down to nearest figure (kW)
Below 0.250.001
0.25 to 0.990.01
1 to 9.90.1
10 to 501

(b) In rounding the nominal power in accordance with paragraph (a) of this section the RMS shall be adjusted accordingly. If rounding upward to the nearest figure would result in objectionable interference, the nominal power specified on the application is to be rounded downward to the next nearest figure and the RMS adjusted accordingly.

[50 FR 18821, May 2, 1985, as amended at 53 FR 1031, Jan. 15, 1988]

§73.33   Antenna systems; showing required.

(a) An application for authority to install a broadcast antenna shall specify a definite site and include full details of the antenna design and expected performance.

(b) All data necessary to show compliance with the terms and conditions of the construction permit must be filed with the license application. If the station is using a directional antenna, a proof of performance must also be filed.

[28 FR 13574, Dec. 14, 1963, as amended at 37 FR 25840, Dec. 5, 1972]

§73.35   Calculation of improvement factors.

A petition for an allotment (See §73.30) in the 1605-1705 kHz band filed by an existing fulltime AM station licensed in the 535-1605 kHz band will be ranked according to the station's calculated improvement factor. (See §73.30). Improvement factors relate to both nighttime and daytime interference conditions and are based on two distinct considerations: (a) Service area lost by other stations due to interference caused by the subject station, and (b) service area of the subject station. These considerations are represented by a ratio. The ratio consists, where applicable, of two separate additive components, one for nighttime and one for daytime. For the nighttime component, to determine the numerator of the ratio (first consideration), calculate the RSS and associated service area of the stations (co- and adjacent channel) to which the subject station causes nighttime interference. Next, repeat the RSS and service area calculations excluding the subject station. The cumulative gain in the above service area is the numerator of the ratio. The denominator (second consideration) is the subject station's interference-free service area. For the daytime component, the composite amount of service lost by co-channel and adjacent channel stations, each taken individually, that are affected by the subject station, excluding the effects of other assignments during each study, will be used as the numerator of the daytime improvement factor. The denominator will consist of the actual daytime service area (0.5 mV/m contour) less any area lost to interference from other assignments. The value of this combined ratio will constitute the petitioner's improvement factor. Notwithstanding the requirements of §73.153, for uniform comparisons and simplicity, measurement data will not be used for determining improvement factors and FCC figure M-3 ground conductivity values are to be used exclusively in accordance with the pertinent provisions of §73.183(c)(1).

[56 FR 64858, Dec. 12, 1991]

§73.37   Applications for broadcast facilities, showing required.

(a) No application will be accepted for a new station if the proposed operation would involve overlap of signal strength contours with any other station as set forth below in this paragraph; and no application will be accepted for a change of the facilities of an existing station if the proposed change would involve such overlap where there is not already such overlap between the stations involved:

Frequency separation (kHz)Contour of proposed station (classes B, C and D) (mV/m)Contour of any other station (mV/m)
00.005
0.025
0.500
0.100 (Class A).
0.500(Other classes).
0.025 (All classes).
100.250
0.500
0.500(All classes).
0.250 (All classes).
205
5
5 (All classes).
5 (All classes).
302525 (All classes).

(b) In determining overlap received, an application for a new Class C station with daytime power of 250 watts, or greater, shall be considered on the assumption that both the proposed operation and all existing Class C stations operate with 250 watts and utilize non-directional antennas.

(c) If otherwise consistent with the public interest, an application requesting an increase in the daytime power of an existing Class C station on a local channel from 250 watts to a maximum of 1kW, or from 100 watts to a maximum of 500 watts, may be granted notwithstanding overlap prohibited by paragraph (a) of this section. In the case of a 100 watt Class C station increasing daytime power, the provisions of this paragraph shall not be construed to permit an increase in power to more than 500 watts, if prohibited overlap would be involved, even if successive applications should be tendered.

(d) In addition to demonstrating compliance with paragraphs (a), and, as appropriate, (b), and (c) of this section, an application for a new AM broadcast station, or for a major change (see §73.3571(a)(1)) in an authorized AM broadcast station, as a condition for its acceptance, shall make a satisfactory showing, if new or modified nighttime operation by a Class B station is proposed, that objectionable interference will not result to an authorized station, as determined pursuant to §73.182(1).

(e) An application for an authorization in the 1605-1705 kHz band which has been selected through the petition process (See §73.30) is not required to demonstrate compliance with paragraph (a), (b), (c), or (d) of this section. Instead, the applicant need only comply with the terms of the allotment authorization issued by the Commission in response to the earlier petition for establishment of a station in the 1605-1705 kHz band. Within the allotment authorization, the Commission will specify the assigned frequency and the applicable technical requirements.

(f) Stations on 1580, 1590 and 1600 kHz. In addition to the rules governing the authorization of facilities in the 535-1605 kHz band, stations on these frequencies seeking facilities modifications must protect assignments in the 1610-1700 kHz band. Such protection shall be afforded in a manner which considers the spacings that occur or exist between the subject station and a station within the range 1605-1700 kHz. The spacings are the same as those specified for stations in the frequency band 1610-1700 kHz or the current separation distance, whichever is greater. Modifications that would result in a spacing or spacings that fails to meet any of the separations must include a showing that appropriate adjustment has been made to the radiated signal which effectively results in a site-to-site radiation that is equivalent to the radiation of a station with standard Model I facilities (10 kW-D, 1 kW-N, non-DA, 90 degree antenna ht. & ground system) operating in compliance with all of the above separation distances. In those cases where that radiation equivalence value is already exceeded, a station may continue to maintain, but not increase beyond that level.

Note 1: In the case of applications for changes in the facilities of AM broadcast stations covered by this section, an application will be accepted even though overlap of field strength contours as mentioned in this section would occur with another station in an area where such overlap does not already exist, if:

(1) The total area of overlap with that station would not be increased;

(2) There would be no net increase in the area of overlap with any other station; and

(3) There would be created no area of overlap with any station with which overlap does not now exist.

Note 2: The provisions of this section concerning prohibited overlap of field strength contours will not apply where:

(1) The area of overlap lies entirely over sea water: or

(2) The only overlap involved would be that caused to a foreign station, in which case the provisions of the applicable international agreement, as identified in §73.1650, will apply. When overlap would be received from a foreign station, the provisions of this section will apply, except where there would be overlap with a foreign station with a frequency separation of 20 kHz, in which case the provisions of the international agreement will apply in lieu of this section.

Note 3: In determining the number of “authorized” aural transmission facilities in a given community, applications for that community in hearing or otherwise having protected status under specified “cut-off” procedures shall be considered as existing stations. In the event that there are two or more mutually exclusive protected applications seeking authorization for the proposed community it will be assumed that only one is “authorized.”

Note 4: A “transmission facility” for a community is a station licensed to the community. Such a station provides a “transmission service” for that community.

[56 FR 64858, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

§73.44   AM transmission system emission limitations.

(a) The emissions of stations in the AM service shall be attenuated in accordance with the requirements specified in paragraph (b) of this section. Emissions shall be measured using a properly operated and suitable swept-frequency RF spectrum analyzer using a peak hold duration of 10 minutes, no video filtering, and a 300 Hz resolution bandwidth, except that a wider resolution bandwidth may be employed above 11.5 kHz to detect transient emissions. Alternatively, other specialized receivers or monitors with appropriate characteristics may be used to determine compliance with the provisions of this section, provided that any disputes over measurement accuracy are resolved in favor of measurements obtained by using a calibrated spectrum analyzer adjusted as set forth above.

(b) Emissions 10.2 kHz to 20 kHz removed from the carrier must be attenuated at least 25 dB below the unmodulated carrier level, emissions 20 kHz to 30 kHz removed from the carrier must be attenuated at least 35 dB below the unmodulated carrier level, emissions 30 kHz to 60 kHz removed from the carrier must be attenuated at least [5 + 1 dB/kHz] below the unmodulated carrier level, and emissions between 60 kHz and 75 kHz of the carrier frequency must be attenuated at least 65 dB below the unmodulated carrier level. Emissions removed by more than 75 kHz must be attenuated at least 43 + 10 Log (Power in watts) or 80 dB below the unmodulated carrier level, whichever is the lesser attenuation, except for transmitters having power less than 158 watts, where the attenuation must be at least 65 dB below carrier level.

(c) Should harmful interference be caused to the reception of other broadcast or non-broadcast stations by out of band emissions, the licensee may be directed to achieve a greater degree of attentuation than specified in paragraphs (a) and (b) of this section.

(d) Measurements to determine compliance with this section for transmitter type acceptance are to be made using signals sampled at the output terminals of the transmitter when operating into an artificial antenna of substantially zero reactance. Measurements made of the emissions of an operating station are to be made at ground level approximately 1 kilometer from the center of the antenna system. When a directional antenna is used, the carrier frequency reference field strength to be used in order of preference shall be:

(1) The measure non-directional field strength.

(2) The RMS field strength determined from the measured directional radiation pattern.

(3) The calculated expected field strength that would be radiated by a non-directional antenna at the station authorized power.

(e) Licensees of stations complying with the ANSI/EIA-549-1988, NRSC-1 AM Preemphasis/Deemphasis and Broadcast Transmission Bandwidth Specifications (NRSC-1), prior to June 30, 1990 or from the original commencement of operation will, until June 30, 1994, be considered to comply with paragraphs (a) and (b) of this section, absent any reason for the Commission to believe otherwise. Such stations are waived from having to make the periodic measurements required in §73.1590(a)(6) until June 30, 1994. However, licensees must make measurements to determine compliance with paragraphs (a) and (b) of this section upon receipt of an Official Notice of Violation or a Notice of Apparent Liability alleging noncompliance with those provisions, or upon specific request by the Commission.

[47 FR 8588, Mar. 1, 1982, as amended at 49 FR 3999, Feb. 1, 1984]

§73.45   AM antenna systems.

(a) All applicants for new, additional, or different AM station facilities and all licensees requesting authority to change the transmitting system site of an existing station must specify an antenna system, the efficiency of which complies with the requirements for the class and power of station. (See §§73.186 and 73.189.)

(1) An application for authority to install an AM broadcast antenna must specify a definite site and include full details of the antenna system design and expected performance.

(2) All data necessary to show compliance with the terms and conditions of the construction permit must be filed with the application for the station license to cover the construction. If the station has constructed a directional antenna, a directional proof of performance must be filed. See §§73.150 through 73.157.

(b) The simultaneous use of a common antenna or antenna structure by more than one AM station or by a station of any other type or service may be authorized provided:

(1) Engineering data are submitted showing that satisfactory operation of each station will be obtained without adversely affecting the operation of the other station(s).

(2) The minimum field strength for each AM station complies with §73.189(b).

(c) Should any changes be made or otherwise occur which would possibly alter the resistance of the antenna system, the licensee must commence the determination of the operating power by a method described in §73.51(a)(1) or (d). (If the changes are due to the addition of antennas to the AM tower, see §1.30003.) Upon completion of any necessary repairs or adjustments, or upon completion of authorized construction or modifications, the licensee must make a new determination of the antenna resistance using the procedures described in §73.54. Operating power should then be determined by a direct method as described in §73.51. Notification of the value of resistance of the antenna system must be filed with the FCC in Washington, DC as follows:

(1) Whenever the measurements show that the antenna or common point resistance differs from that shown on the station authorization by more than 2%, FCC Form 302 must be filed with the information and measurement data specified in §73.54(d).

(2) Whenever AM stations use direct reading power meters pursuant to §73.51, a letter notification to the FCC in Washington, DC, Attention: Audio Division, Media Bureau, must be filed in accordance with §73.54(e).

[43 FR 53735, Nov. 17, 1978, as amended at 45 FR 28141, Apr. 28, 1980; 47 FR 8589, Mar. 1, 1982; 50 FR 32416, Aug. 12, 1985; 51 FR 2707; Jan. 21, 1986; 51 FR 26250, July 22, 1986; 63 FR 33875, June 22, 1998; 67 FR 13231, Mar. 21, 2002; 78 FR 66298, Nov. 5, 2013]

§73.49   AM transmission system fencing requirements.

Antenna towers having radio frequency potential at the base (series fed, folded unipole, and insulated base antennas) must be enclosed within effective locked fences or other enclosures. Ready access must be provided to each antenna tower base for meter reading and maintenance purposes at all times. However, individual tower fences need not be installed if the towers are contained within a protective property fence.

[51 FR 2707, Jan. 21, 1986]

§73.51   Determining operating power.

(a) Except in those circumstances described in paragraph (d) of this section, the operating power shall be determined by the direct method. The direct method consists of either:

(1) using a suitable instrument for determining the antenna's input power directly from the RF voltage, RF current, and phase angle; or

(2) calculating the product of the licensed antenna or common point resistance at the operating frequency (see §73.54), and the square of the indicated unmodulated antenna current at that frequency, measured at the point where the resistance has been determined.

(b) The authorized antenna input power for each station shall be equal to the nominal power for such station, with the following exceptions:

(1) For stations with nominal powers of 5 kW, or less, the authorized antenna input power to directional antennas shall exceed the nominal power by 8 percent.

(2) For stations with nominal powers in excess of 5 kW, the authorized antenna input power to directional antennas shall exceed the nominal power by 5.3 percent.

(3) In specific cases, it may be necessary to limit the radiated field to a level below that which would result if normal power were delivered to the antenna. In such cases, excess power may be dissipated in the antenna feed circuit, the transmitter may be operated with power output at a level which is less than the rated carrier power, or a combination of the two methods may be used, subject to the conditions given in paragraph (c) of this section.

(i) Where a dissipative network is employed, the authorized antenna current and resistance, and the authorized antenna input power shall be determined at the input terminals of the dissipative network.

(ii) Where the authorized antenna input power is less than the nominal power, subject to the conditions set forth in paragraph (c) of this section, the transmitter may be operated at the reduced power level necessary to supply the authorized antenna input power.

(c) Applications for authority to operate with antenna input power which is less than nominal power and/or to employ a dissipative network in the antenna system shall be made on FCC Form 302. The technical information supplied on section II-A of this form shall be that applying to the proposed conditions of operation. In addition, the following information shall be furnished, as pertinent:

(1) Full details of any network employed for the purpose of dissipating radio frequency energy otherwise delivered to the antenna (see §73.54).

(2) A showing that the transmitter has been type accepted or notified for operation at the proposed power output level, or, in lieu thereof:

(i) A full description of the means by which transmitter output power will be reduced.

(ii) Where the proposed transmitter power output level(s) is less than 90% of the rated power of the transmitter, equipment performance measurements must be made to confirm that the station transmissions conform to the emission limitation specified in §73.44, under all conditions of program operation.

(iii) A showing that, at the proposed power output level, means are provided for varying the transmitter output within a tolerance of ±10 percent, to compensate for variations in line voltage or other factors which may affect the power output level.

(d) When it is not possible or appropriate to use the direct method of power determination due to technical reasons, the indirect method of determining operating power (see paragraphs (e) and (f) of this section) may be used on a temporary basis. A notation must be made in the station log indicating the dates of commencement and termination of measurement using the indirect method of power determination.

(e) The antenna input power is determined indirectly by applying an appropriate factor to the input power to the last radio-frequency power amplifier stage of the transmitter, using the following formula:

Where:

Antenna input power = Ep × Ip × F

Ep=DC input voltage of final radio stage.

Ip=Total DC input current of final radio stage.

F= Efficiency factor.

(1) If the above formula is not appropriate for the design of the transmitter final amplifier, use a formula specified by the transmitter manufacturer with other appropriate operating parameters.

(2) The value of F applicable to each mode of operation must be determined and a record kept thereof with a notation as to its derivation. This factor is to be established by one of the methods described in paragraph (f) of this section and retained in the station records.

(f) The value of F is to be determined by one of the following procedures listed in order of preference:

(1) If the station had previously been authorized and operating by determining the antenna input power by the direct method, the factor F is the ratio of the antenna input power (determined by the direct method) to the corresponding final radio frequency power amplifier input power.

(2) If a station has not been previously in regular operation with the power authorized for the period of indirect power determination, if a new transmitter has been installed, or if, for any other reason, the determination of the factor F by the method described in paragraph (f)(1) of this section is impracticable:

(i) The factor F as shown in the transmitter manufacturer's test report, if such a test report specifies a unique value of F for the power level and frequently used; or

(ii) The value determined by reference to the following table:

Factor(F)Method of modulationMaximum rated carrier powerClass of amplifier
0.70Plate1 kW or less
.80Plate2.5 kW and over
.35Low level0.25 kW and overB
.65Low level0.25 kW and overBC1
.35Grid0.25 kW and over

1All linear amplifier operation where efficiency approaches that of class C operation.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, as amended, 1068, 1082, as amended; 47 U.S.C. 154, 155, 303. Interpret or apply secs. 301, 303, 307, 48 Stat. 1081, 1082, as amended, 47 U.S.C. 301, 303, 307)

[37 FR 7516, Apr. 15, 1972, as amended at 42 FR 36827, July 18, 1977; 42 FR 61863, Dec. 7, 1977; 44 FR 36036, June 20, 1979; 47 FR 28387, June 30, 1982; 48 FR 38477, Aug. 24, 1983; 48 FR 44805, Sept. 30, 1983; 49 FR 3999, Feb. 1, 1984; 49 FR 4210, Feb. 3, 1984; 49 FR 49850, Dec. 24, 1984; 50 FR 24521, June 11, 1985; 52 FR 10570, Apr. 2, 1987]

§73.53   Requirements for authorization of antenna monitors.

(a) Antenna monitors shall be verified for compliance with the technical requirements in this section. The procedure for verification is specified in subpart J of part 2 of the FCC's rules.

(b) An antenna monitor shall meet the following specifications:

(1) The monitor shall be designed to operate in the 535-1705 kHz band.

(2) The monitor shall be capable of indicating any phase difference between two RF voltages of the same frequency over a range of from 0 to 360°.

(3) The monitor shall be capable of indicating the relative amplitude of two RF voltages.

(4) The device used to indicate phase differences shall indicate in degrees, and shall be graduated in increments of 2°, or less. If a digital indicator is provided, the smallest increment shall be 0.5°, or less.

(5) The device used to indicate relative amplitudes shall be graduated in increments which are 1 percent, or less, of the full scale value. If a digital indicator is provided, the smallest increment shall be 0.1 percent, or less, of the full scale value.

(6) The monitor shall be equipped with means, if necessary, to resolve ambiguities in indication.

(7) If the monitor is provided with more than one RF input terminal in addition to a reference input terminal, appropriate switching shall be provided in the monitor so that the signal at each of these RF inputs may be selected separately for comparison with the reference input signal.

(8) Each RF input of the monitor shall provide a termination of such characteristics that, when connected to a sampling line of an impedance specified by the manufacturer the voltage reflection coefficient shall be 3 percent or less.

(9) The monitor, if intended for use by stations operating directional antenna systems by remote control, shall be designed so that the switching functions required by paragraph (b)(7) of this section may be performed from a point external to the monitor, and phase and amplitude indications be provided by external meters. The indications of external meters furnished by the manufacturer shall meet the specifications for accuracy and repeatability of the monitor itself, and the connection of these meters to the monitor, or of other indicating instruments with electrical characteristics meeting the specifications of the monitor manufacturer shall not affect adversely the performance of the monitor in any respect.

(10) Complete and correct schematic diagrams and operating instructions shall be retained by the party responsible for verification of the equipment and submitted to the FCC upon request. For the purpose of equipment authorization, these diagrams and instructions shall be considered as part of the monitor.

(11) When an RF signal of an amplitude within a range specified by the manufacturer is applied to the reference RF input terminal of the monitor, and another RF signal of the same frequency and of equal or lower amplitude is applied to any other selected RF input terminal, indications shall be provided meeting the following specifications.

(i) The accuracy with which any difference in the phases of the applied signals is indicated shall be ±1°, or better, for signal amplitude ratios of from 2:1 to 1:1, and ±2°, or better, for signal amplitude ratios in excess of 2:1 and up to 5:1.

(ii) The repeatability of indication of any difference in the phases of the applied signals shall be ±1°, or better.

(iii) The accuracy with which the relative amplitudes of the applied signals is indicated, over a range in which the ratio of these amplitudes is between 2:1 and 1:1, shall be ±2 percent of the amplitude ratio, or better, and for amplitude ratios in excess of 2:1 and up to 5:1, ±5 percent of the ratio, or better.

(iv) The repeatability of indication of the relative amplitudes of the applied signals, over a range where the ratio of these amplitudes is between 5:1 and 1:1, shall be ±2 percent of the amplitude ratio, or better.

(v) The modulation of the RF signals by a sinusoidal wave of any frequency between 100 and 10,000 Hz, at any amplitude up to 90 percent shall cause no deviation in an indicated phase difference from its value, as determined without modulation, greater than ±0.5°.

(12) The performance specifications set forth in paragraph (b)(11) of this section, shall be met when the monitor is operated and tested under the following conditions.

(i) After continuous operation for 1 hour, the monitor shall be calibrated and adjusted in accordance with the manufacturer's instructions.

(ii) The monitor shall be subjected to variations in ambient temperature between the limits of 10 and 40 °C; external meters furnished by the manufacturer will be subjected to variations between 15 and 30 °C.

(iii) Powerline supply voltage shall be varied over a range of from 10 percent below to 10 percent above the rated supply voltage.

(iv) The amplitude of the reference signal shall be varied over the operating range specified by the manufacturer, and in any case over a range of maximum to minimum values of 3 to 1.

(v) The amplitude of the comparison signal shall be varied from a value which is 0.2 of the amplitude of the reference signal to a value which is equal in amplitude to the reference signal.

(vi) Accuracy shall be determined for the most adverse combination of conditions set forth above.

(vii) Repeatability shall be determined as that which may be achieved under the specified test conditions over a period of 7 days, during which no calibration or adjustment of the instrument, subsequent to the initial calibration, shall be made.

(viii) The effects of modulation of the RF signal shall be separately determined, and shall not be included in establishing values for accuracy and repeatability.

Note: In paragraph (b)(1) of this section, the requirement that monitors be capable of operation in the 535-1705 kHz band shall apply only to equipment manufactured after July 1, 1992. Use of a monitor in the 1605-1705 kHz band which is not approved for such operation will be permitted pending the general availability of 535-1705 kHz band monitors if a manufacturer can demonstrate, in the interim, that its monitor performs in accordance with the standards in this section on these 10 channels.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[38 FR 1917, Jan. 19, 1973, as amended at 49 FR 3999, Feb. 1, 1984; 49 FR 29069, July 18, 1984; 50 FR 32416, Aug. 12, 1985; 50 FR 47054, Nov. 14, 1985; 51 FR 2707, Jan. 21, 1986; 56 FR 64859, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992; 60 FR 55480, Nov. 1, 1995; 63 FR 36604, July 7, 1998; 66 FR 20755, Apr. 25, 2001]

§73.54   Antenna resistance and reactance measurements.

(a) The resistance of an omnidirectional series fed antenna is measured at either the base of the antenna without intervening coupling or tuning networks, or at the point the transmission line connects to the output terminals of the transmitter. The resistance of a shunt excited antenna may be measured at the point the radio frequency energy is transferred to the feed wire circuit or at the output terminals of the transmitter.

(b) The resistance and reactance of a directional antenna shall be measured at the point of common radiofrequency input to the directional antenna system after the antenna has been finally adjusted for the required radiation pattern.

(c) A letter of notification must be filed with the FCC in Washington, DC, Attention: Audio Division, Media Bureau, when determining power by the direct method pursuant to §73.51. The letter must specify the antenna or common point resistance at the operating frequency. The following information must also be kept on file at the station:

(1) A full description of the method used to make measurements.

(2) A schematic diagram showing clearly all components of coupling circuits, the point of resistance measurement, the location of the antenna ammeter, connections to and characteristics of all tower lighting isolation circuits, static drains, and any other fixtures connected to and supported by the antenna, including other antennas and associated networks. Any network or circuit component used to dissipate radio frequency power shall be specifically identified, and the impedances of all components which control the level of power dissipation, and the effective input resistance of the network must be indicated.

(d) AM stations using direct reading power meters in accordance with §73.51, can either submit the information required by paragraph (c) of this section or submit a statement indicating that such a meter is being used. Subsequent station licenses will indicate the use of a direct reading power meter in lieu of the antenna resistance value in such a situation.

[66 FR 20755, Apr. 25, 2001,as amended at 67 FR 13231, Mar. 21, 2002]

§73.57   Remote reading antenna and common point ammeters.

Remote reading antenna and common point ammeters may be used without further authority according to the following conditions:

(a) Remote reading antenna or common point ammeters may be provided by:

(1) Inserting second radio frequency current sensing device directly in the antenna circuit with remote leads to the indicating instruments.

(2) Inductive coupling to radio frequency current sensing device for providing direct current to indicating instrument.

(3) Capacity coupling to radio frequency current sensing device for providing direct current to indicating instrument.

(4) Current transformer connected to radio frequency current sensing device for providing direct current to indicating instrument.

(5) Using transmission line current meter at transmitter as remote reading ammeter. See paragraph (c) of this section.

(6) Using the indications of the antenna (phase) monitor, provided that when the monitor is used to obtain remote reading indication of non-directional antenna base current, the monitor calibration can be independently made and maintained for each mode of operation.

(b) Devices used for obtaining remote reading antenna or common point current indications, except antenna monitor coupling elements, shall be located at the same point as, but below (transmitter side) the associated main ammeter.

(c) In the case of shunt-excited antennas, the transmission line current meter at the transmitter may be considered as the remote antenna ammeter provided the transmission line is terminated directly into the excitation circuit feed line, which shall employ series tuning only (no shunt circuits of any type shall be employed) and insofar as practicable, the type and scale of the transmission line meter should be the same as those of the excitation circuit feed line meter (meter in slant wire feed line or equivalent).

(d) Each remote reading ammeter shall be accurate to within 2 percent of the value read on its corresponding regular ammeter.

(e) All remote reading ammeters shall conform with the specifications for regular antenna ammeters.

(f) Meters with arbitrary scale divisions may be used provided that calibration charts or curves are provided at the transmitter control point showing the relationship between the arbitrary scales and the reading of the main meters.

(g) If a malfunction affects the remote reading indicators of the antenna or common point ammeter, the operating power may be determined by a method using alternative procedures as described in §73.51.

[41 FR 36817, Sept. 1, 1976, as amended at 48 FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24, 1984; 50 FR 32416, Aug. 12, 1985; 60 FR 55480, Nov. 1, 1995]

§73.58   Indicating instruments.

(a) Each AM broadcast station must be equipped with indicating instruments which conform with the specifications described in §73.1215 for determining power by the direct and indirect methods, and with such other instruments as are necessary for the proper adjustment, operation, and maintenance of the transmitting system. However, auxiliary transmitters with a nominal power rating of 100 watts or less are not required to be equipped with instruments to determine power by the indirect method provided that the licensee can determine the antenna input power at all times.

(b) Since it is usually impractical to measure the actual antenna current of a shunt excited antenna system, the current measured at the input of the excitation circuit feed line is accepted as the antenna current.

(c) The function of each instrument shall be clearly and permanently shown on the instrument itself or on the panel immediately adjacent thereto.

(d) In the event that any one of these indicating instruments becomes defective when no substitute which conforms with the required specifications is available, the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the Commission. If the defective instrument is the antenna current meter of a nondirectional station which does not employ a remote antenna ammeter, or if the defective instrument is the common point meter of a station which employs a directional antenna and does not employ a remote common point meter, the operating power shall be determined by a method described in §73.51(a)(1) or §73.51(d) during the entire time the station is operated without the antenna current meter or common point meter. However, if a remote meter is employed and the antenna current ammeter or common point meter becomes defective, the remote meter can be used to determine operating power pending the return to service of the regular meter.

(e) If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period, information requested in accordance with §73.3549 may be filed by letter with the FCC in Washington, DC, Attention: Audio Division, Media Bureau, to request additional time as may be required to complete repairs of the defective instrument.

[41 FR 36817, Sept. 1, 1976, as amended at 48 FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24, 1984; 50 FR 32416, Aug. 12, 1985; 51 FR 2707, Jan. 21, 1986; 53 FR 2498, Jan. 28, 1988; 63 FR 33876, June 22, 1998; 66 FR 20755, Apr. 25, 2001; 67 FR 13231, Mar. 21, 2002]

§73.61   AM directional antenna field strength measurements.

(a) Each AM station using a directional antenna with monitoring point locations specified in the instrument of authorization must make field strength measurements as often as necessary to ensure that the field at each of those points does not exceed the value specified in the station authorization. Additionally, stations not having an approved sampling system must make the measurements once each calendar quarter at intervals not exceeding 120 days. The provision of this paragraph supersedes any schedule specified on a station license issued prior to January 1, 1986. The results of the measurements are to be entered into the station log pursuant to the provisions of §73.1820.

(b) If the AM license was granted on the basis of field strength measurements performed pursuant to §73.151(a), partial proof of performance measurements using the procedures described in §73.154 must be made whenever the licensee has reason to believe that the radiated field may be exceeding the limits for which the station was most recently authorized to operate.

(c) A station may be directed to make a partial proof of performance by the FCC whenever there is an indication that the antenna is not operating as authorized.

[50 FR 47054, Nov. 14, 1985, as amended at 73 FR 64560, Oct. 30, 2008]

§73.62   Directional antenna system operation and tolerances.

(a) Each AM station operating a directional antenna must maintain the relative amplitudes of the antenna currents, as indicated by the antenna monitor, within 5% of the values specified on the instrument of authorization. Directional antenna relative phases must be maintained within 3 degrees of the values specified on the instrument of authorization.

(b) In the event of a failure of system components, improper pattern switching or any other event that results in operation substantially at variance from the radiation pattern specified in the instrument of authorization for the pertinent time of day, operation must be terminated within three minutes unless power can be reduced sufficiently to eliminate any excessive radiation. See §73.1350(e).

(1) Any variation of operating parameters by more than ±15 percent sample current ratio or ±10 degrees in phase, any monitor point that exceeds 125 percent of the licensed limit, or any operation at variance that results in complaints of interference shall be considered operation substantially at variance from the license and will require immediate corrective action.

(2) [Reserved]

(c) In the event of minor variations of directional antenna operating parameters from the tolerances specified in paragraph (a) of this section, the following procedures will apply:

(1) The licensee shall measure and log every monitoring point at least once for each mode of directional operation. Subsequent variations in operating parameters will require the remeasuring and logging of every monitoring point to assure that the authorized monitoring point limits are not being exceeded. The licensee will be permitted 24 hours to accomplish these actions; provided that, the date and time of the failure to maintain proper operating parameters have been recorded in the station log.

(2) Provided each monitoring point is within its specified limit, operation may continue for a period up to 30 days before a request for Special Temporary Authority (STA) must be filed, pursuant to paragraph (c)(4) of this section, to operate with parameters at variance from the provisions of paragraph (a) of this section.

(3) If any monitoring point exceeds its specified limit, the licensee must either terminate operation within three hours or reduce power in accordance with the applicable provisions of §73.1350(d), in order to eliminate any possibility of interference or excessive radiation in any direction.

(4) If operation pursuant to paragraph (c)(3) of this section is necessary, or before the 30-day period specified in paragraph (c)(2) of this §expires, the licensee must request a Special Temporary Authority (STA) in accordance with section 73.1635 to continue operation with parameters at variance and/or with reduced power along with a statement certifying that all monitoring points will be continuously maintained within their specified limits.

(d) In any other situation in which it might reasonably be anticipated that the operating parameters might vary out of tolerance (such as planned array repairs or adjustment and proofing procedures), the licensee shall, before such activity is undertaken, obtain a Special Temporary Authority (STA) in accordance with §73.1635 in order to operate with parameters at variance and/or with reduced power as required to maintain all monitoring points within their specified limits.

[72 FR 44422, Aug. 8, 2007]

§73.68   Sampling systems for antenna monitors.

(a) Each AM station permittee authorized to construct a new directional antenna system which will be subject to a proof of performance based on field strength measurements, as described in §73.151(a) or (b), must install the sampling system in accordance with the following specifications:

(1) Devices used to extract or sample the current and the transmission line connecting the sampling elements to the antenna monitor must provide accurate and stable signals to the monitor (e.g., rigidly mounted and non-rotatable loops and all system components protected from physical and environmental disturbances).

(2) Sampling lines for directional antennas may be of different lengths provided the phase difference of signals at the monitor are less than 0.5 degrees between the shortest and longest cable lengths due to temperature variations to which the system is exposed.

(3) Other configurations of sampling systems may be used upon demonstration of stable operation to the FCC.

(b) An AM station permittee authorized to construct a directional antenna system which will be subject to a proof of performance based on moment method modeling, as described in §73.151(c), shall install a sampling system conforming to the requirements set forth in that section.

(c) A station having an antenna sampling system constructed according to the specifications given in paragraph (a) of this section may obtain approval of that system by submitting an informal letter request to the FCC in Washington, DC, Attention: Audio Division, Media Bureau. The request for approval, signed by the licensee or authorized representative, must contain sufficient information to show that the sampling system is in compliance with all requirements of paragraph (a) of this section.

Note to paragraph (c): A public notice dated December 9, 1985 giving additional information on approval of antenna sampling systems is available through the Internet at http://www.fcc.gov/mb/audio/decdoc/letter/1985-12-09-sample.html.

(d) In the event that the antenna monitor sampling system is temporarily out of service for repair or replacement, the station may be operated, pending completion of repairs or replacement, for a period not exceeding 120 days without further authority from the FCC if all other operating parameters and the field monitoring point values are within the limits specified on the station authorization.

(e) If the antenna sampling system is modified or components of the sampling system are replaced, the following procedure shall be followed:

(1) Special Temporary Authority (see §73.1635) shall be requested and obtained from the Commission's Audio Division, Media Bureau in Washington to operate with parameters at variance with licensed values pending issuance of a modified license specifying parameters subsequent to modification or replacement of components.

(2) Immediately prior to modification or replacement of components of the sampling system, and after a verification that all monitoring point values and operating parameters are within the limits or tolerances specified in the rules, the following indications must be recorded for each radiation pattern: Final plate current and plate voltage, common point current, antenna monitor phase and current indications, and the field strength at each monitoring point. Subsequent to these modifications or changes the procedure must be repeated.

(3) If monitoring point field strengths or antenna monitor parameters exceed allowable limits following the replacement or modification of that portion of the sampling system above the base of the towers, a partial proof of performance shall be executed in accordance with §73.154 . The partial proof of performance shall be accompanied by common point impedance measurements made in accordance with §73.54.

(4) Request for modification of license shall be submitted to the FCC in Washington, DC, within 30 days of the date of sampling system modification or replacement. Such request shall specify the transmitter plate voltage and plate current, common point current, base currents and their ratios, antenna monitor phase and current indications, and all other data obtained pursuant to this paragraph.

(f) If an existing sampling system is found to be patently of marginal construction, or where the performance of a directional antenna is found to be unsatisfactory, and this deficiency reasonably may be attributed, in whole or in part, to inadequacies in the antenna monitoring system, the FCC may require the reconstruction of the sampling system in accordance with requirements specified above.

[41 FR 7405, Feb. 18, 1976]

Editorial Note: For Federal Register citations affecting §73.68, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.

§73.69   Antenna monitors.

(a) Each station using a directional antenna must have in operation at the transmitter site an FCC authorized antenna monitor.

(b) In the event that the antenna monitor sampling system is temporarily out of service for repair or replacement, the station may be operated, pending completion of repairs or replacement, for a period not exceeding 120 days without further authority from the FCC if all other operating parameters, and the field monitoring point values are within the limits specified on the station authorization.

(c) If conditions beyond the control of the licensee prevent the restoration of the monitor to service within the allowed period, an informal letter request in accordance with §73.3549 of the Commission's rules must be filed with the FCC, Attention: Audio Division, Media Bureau in Washington, DC for such additional time as may be required to complete repairs of the defective instrument.

(d) If an authorized antenna monitor is replaced by another antenna monitor, the following procedure shall be followed:

(1) Temporary authority shall be requested and obtained from the Commission in Washington to operate with parameters at variance with licensed values, pending issuance of a modified license specifying new parameters.

(2) Immediately before the replacement of the antenna monitor, after a verification that all monitoring point values and the common point current reading are within the limits or tolerances specified in the rules, the following indications must be recorded for each radiation pattern: Final plate current and plate voltage, common point current, antenna monitor phase and current indications, and the field strength at each monitoring point.

(3) With the new monitor substituted for the old, all indications specified in paragraph (d)(2) of this section, again must be read. If no change has occurred in the indication for any parameter other than the indications of the antenna monitor, the new antenna monitor indications must be deemed to be those reflecting correct array adjustments.

(4) If it cannot be established by the observations required in paragraph (d)(2) of this section that the common point current reading and the monitoring point values are within the tolerances or limits prescribed by the rules and the instrument of authorization, or if the substitution of the new antenna monitor for the old results in changes in these parameters, a partial proof of performance shall be executed and analyzed in accordance with §73.154.

(5) An informal letter request for modification of license shall be submitted to the FCC, Attention: Audio Division, Media Bureau in Washington, DC within 30 days of the date of monitor replacement. Such request shall specify the make, type, and serial number of the replacement monitor, phase and sample current indications, and other data obtained pursuant to this paragraph (d).

(e) The antenna monitor must be calibrated according to the manufacturer's instructions as often as necessary to ensure its proper operation.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, as amended, 1082, as amended; 47 U.S.C. 154, 303. Interpret or apply secs. 301, 303, 307, 48 Stat. 1081, 1082, as amended, 1083, as amended, 47 U.S.C. 301, 303, 307)

[38 FR 1918, Jan. 19, 1973]

Editorial Note: For Federal Register citations affecting §73.69 see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.

§73.72   Operating during the experimental period.

(a) An AM station may operate during the experimental period (the time between midnight and sunrise, local time) on its assigned frequency and with its authorized power for the routine testing and maintenance of its transmitting system, and for conducting experimentation under an experimental authorization, provided no interference is caused to other stations maintaining a regular operating schedule within such period.

(b) No station licensed for “daytime” or “specified hours” of operation may broadcast any regular or scheduled program during this period.

(c) The licensee of an AM station shall operate or refrain from operating its station during the experimental period as directed by the FCC to facilitate frequency measurements or for the determination of interference.

[43 FR 32780, July 28, 1978, as amended at 56 FR 64859, Dec. 12, 1991]

§73.88   Blanketing interference.

The licensee of each broadcast station is required to satisfy all reasonable complaints of blanketing interference within the 1 V/m contour.

Note: For more detailed instructions concerning operational responsibilities of licensees and permittees under this section, see §73.318 (b), (c) and (d).

[28 FR 13574, Dec. 14, 1963, as amended at 56 FR 64859, Dec. 12, 1991]

§73.99   Presunrise service authorization (PSRA) and postsunset service authorization (PSSA).

(a) To provide maximum uniformity in early morning operation compatible with interference considerations, and to provide for additional service during early evening hours for Class D stations, provisions are made for presunrise service and postsunset service. The permissible power for presunrise or postsunset service authorizations shall not exceed 500 watts, or the authorized daytime or critical hours power (whichever is less). Calculation of the permissible power shall consider only co-channel stations for interference protection purposes.

(b) Presunrise service authorizations (PSRA) permit:

(1) Class D stations operating on Mexican, Bahamian, and Canadian priority Class A clear channels to commence PSRA operation at 6 a.m. local time and to continue such operation until the sunrise times specified in their basic instruments of authorization.

(2) Class D stations situated outside 0.5 mV/m-50% skywave contours of co-channel U.S. Class A stations to commence PSRA operation at 6 a.m. local time and to continue such operation until sunrise times specified in their basic instruments of authorization.

(3) Class D stations located within co-channel 0.5 mV/m-50% skywave contours of U.S. Class A stations, to commence PSRA operation either at 6 a.m. local time, or at sunrise at the nearest Class A station located east of the Class D station (whichever is later), and to continue such operation until the sunrise times specified in their basic instruments of authorization.

(4) Class B and Class D stations on regional channels to commence PSRA operation at 6 a.m. local time and to continue such operation until local sunrise times specified in their basic instruments of authorization.

(c) Extended Daylight Saving Time Pre-Sunrise Authorizations:

(1) Between the first Sunday in April and the end of the month of April, Class D stations will be permitted to conduct pre-sunrise operation beginning at 6 a.m. local time with a maximum power of 500 watts (not to exceed the station's regular daytime or critical hours power), reduced as necessary to comply with the following requirements:

(i) Full protection is to be provided as specified in applicable international agreements.

(ii) Protection is to be provided to the 0.5 mV/m groundwave signals of co-channel U.S. Class A stations; protection to the 0.5 mV/m-50% skywave contours of these stations is not required.

(iii) In determining the protection to be provided, the effect of each interfering signal will be evaluated separately. The presence of interference from other stations will not reduce or eliminate the required protection.

(iv) Notwithstanding the requirements of paragraph (c)(1) (ii) and (iii) of this section, the stations will be permitted to operate with a minimum power of 10 watts unless a lower power is required by international agreement.

(2) The Commission will issue appropriate authorizations to Class D stations not previously eligible to operate during this period. Class D stations authorized to operate during this presunrise period may continue to operate under their current authorization.

(d) Postsunset service authorizations (PSSA) permit:

(1) Class D stations located on Mexican, Bahamian, and Canadian priority Class A clear channels to commence PSSA operation at sunset times specified in their basic instruments of authorization and to continue for two hours after such specified times.

(2) Class D stations situated outside 0.5 mV/m-50% skywave contours of co-channel U.S. Class A stations to commence PSSA operations at sunset times specified in their basic instruments of authorization and to continue for two hours after such specified times.

(3) Class D stations located within co-channel 0.5 mV/m-50% skywave contours of U.S. Class A stations to commence PSSA operation at sunset times specified in their basic instruments of authorization and to continue such operation until two hours past such specified times, or until sunset at the nearest Class A station located west of the Class D station, whichever is earlier. Class D stations located west of the Class A station do not qualify for PSSA operation.

(4) Class D stations on regional channels to commence PSSA operation at sunset times specified on their basic instruments of authorization and to continue such operation until two hours past such specified times.

(e) Procedural Matters. (1) Applications for PSRA and PSSA operation are not required. Instead, the FCC will calculate the periods of such operation and the power to be used pursuant to the provisions of this section and the protection requirements contained in applicable international agreements. Licensees will be notified of permissible power and times of operation. Presunrise and Postsunset service authority permits operation on a secondary basis and does not confer license rights. No request for such authority need be filed. However, stations intending to operate PSRA or PSSA shall submit by letter, signed as specified in §73.3513, the following information:

(i) Licensee name, station call letters and station location,

(ii) Indication as to whether PSRA operation, PSSA operation, or both, is intended by the station,

(iii) A description of the method whereby any necessary power reduction will be achieved.

(2) Upon submission of the required information, such operation may begin without further authority.

(f) Technical criteria. Calculations to determine whether there is objectionable interference will be determined in accordance with the AM Broadcast Technical Standards, §§73.182 through 73.190, and applicable international agreements. Calculations will be performed using daytime antenna systems, or critical hours antenna systems when specified on the license. In performing calculations to determine assigned power and times for commencement of PSRA and PSSA operation, the following standards and criteria will be used:

(1) Class D stations operating in accordance with paragraphs (b)(1), (b)(2), (d)(1), and (d)(2) of this section are required to protect the nighttime 0.5 mV/m-50% skywave contours of co-channel Class A stations. Where a 0.5 mV/m-50% skywave signal from the Class A station is not produced, the 0.5 mV/m groundwave contour shall be protected.

(2) Class D stations are required to fully protect foreign Class B and Class C stations when operating PSRA and PSSA; Class D stations operating PSSA are required to fully protect U.S. Class B stations. For purposes of determining protection, the nighttime RSS limit will be used in the determination of maximum permissible power.

(3) Class D stations operating in accordance with paragraphs (d)(2) and (d)(3) of this section are required to restrict maximum 10% skywave radiation at any point on the daytime 0.1 mV/m groundwave contour of a co-channel Class A station to 25 µV/m. The location of the 0.1 mV/m contour of the Class A station will be determined by use of Figure M3, Estimated Ground Conductivity in the United States. When the 0.1 mV/m contour extends beyond the national boundary, the international boundary shall be considered the 0.1 mV/m contour.

(4) Class B and Class D stations on regional channels operating PSRA and PSSA (Class D only) are required to provide full protection to co-channel foreign Class B and Class C stations.

(5) Class D stations on regional channels operating PSSA beyond 6 p.m. local time are required to fully protect U.S. Class B stations.

(6) The protection that Class D stations on regional channels are required to provide when operating PSSA until 6 p.m. local time is as follows.

(i) For the first half-hour of PSSA operation, protection will be calculated at sunset plus 30 minutes at the site of the Class D station;

(ii) For the second half-hour of PSSA operation, protection will be calculated at sunset plus one hour at the site of the Class D station;

(iii) For the second hour of PSSA operation, protection will be calculated at sunset plus two hours at the site of the Class D station;

(iv) Minimum powers during the period until 6 p.m. local time shall be permitted as follows:

Calculated powerAdjusted minimum power
From 1 to 45 watts50 watts.
Above 45 to 70 watts75 watts.
Above 70 to 100 watts100 watts.

(7) For protection purposes, the nighttime 25% RSS limit will be used in the determination of maximum permissible power.

(g) Calculations made under paragraph (d) of this section may not take outstanding PSRA or PSSA operations into account, nor will the grant of a PSRA or PSSA confer any degree of interference protection on the holder thereof.

(h) Operation under a PSRA or PSSA is not mandatory, and will not be included in determining compliance with the requirements of §73.1740. To the extent actually undertaken, however, presunrise operation will be considered by the FCC in determining overall compliance with past programming representations and station policy concerning commercial matter.

(i) The PSRA or PSSA is secondary to the basic instrument of authorization with which it is to be associated. The PSRA or PSSA may be suspended, modified, or withdrawn by the FCC without prior notice or right to hearing, if necessary to resolve interference conflicts, to implement agreements with foreign governments, or in other circumstances warranting such action. Moreover, the PSRA or PSSA does not extend beyond the term of the basic authorization.

(j) The Commission will periodically recalculate maximum permissible power and times for commencing PSRA and PSSA for each Class D station operating in accordance with paragraph (c) of this section. The Commission will calculate the maximum power at which each individual station may conduct presunrise operations during extended daylight saving time and shall issue conforming authorizations. These original notifications and subsequent notifications should be associated with the station's authorization. Upon notification of new power and time of commencing operation, affected stations shall make necessary adjustments within 30 days.

(k) A PSRA and PSSA does not require compliance with §§73.45, 73.182 and 73.1560 where the operation might otherwise be considered as technically substandard. Further, the requirements of paragraphs (a)(5), (b)(2), (c)(2), and (d)(2) of §73.1215 concerning the scale ranges of transmission system indicating instruments are waived for PSRA and PSSA operation except for the radio frequency ammeters used in determining antenna input power.

(1) A station having an antenna monitor incapable of functioning at the authorized PSRA and PSSA power when using a directional antenna shall take the monitor reading using an unmodulated carrier at the authorized daytime power immediately prior to commencing PSRA or PSSA operations. Special conditions as the FCC may deem appropriate may be included for PSRA or PSSA to insure operation of the transmitter and associated equipment in accordance with all phases of good engineering practice.

[56 FR 64860, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992, as amended at 58 FR 27950, May 12, 1993]

§73.127   Use of multiplex transmission.

The licensee of an AM broadcast station may use its AM carrier to transmit signals not audible on ordinary consumer receivers, for both broadcast and non-broadcast purposes subject to the following requirements:

(a) Such use does not disrupt or degrade the station's own programs or the programs of other broadcast stations.

(b) AM carrier services that are common carrier in nature are subject to common carrier regulation. Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service. Responsibility for making the initial determinations of whether a particular activity is common carriage rests with the AM station licensee. Initial determinations by licensees are subject to FCC examination and may be reviewed at the FCC's discretion. AM carrier services that are private carrier in nature must notify the Licensing Division of the Private Radio Bureau at Gettysburg, Pennsylvania 17325, by letter, prior to initiating service certifying compliance with 47 CFR parts 90 and 94.

(c) AM carrier services are of a secondary nature under the authority of the AM station authorization, and the authority to provide such communications services may not be retained or transferred in any manner separate from the station's authorization. The grant or renewal of an AM station permit or license is not furthered or promoted by proposed or past service. The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided.

(d) The station identification, delayed recording, and sponsor identification announcements required by §§73.1201, 73.1208, and 73.1212 are not applicable to leased communications services transmitted via services that are not of a general broadcast program nature.

(e) The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable.

(f) Installation of the multiplex transmitting equipment must conform with the requirements of §73.1690(e).

[47 FR 25345, June 11, 1982, as amended at 49 FR 34015, Aug. 28, 1984; 51 FR 41629, Nov. 18, 1986; 51 FR 44478, Dec. 10, 1986]

§73.128   AM stereophonic broadcasting.

(a) An Am broadcast station may, without specific authority from the FCC, transmit stereophonic programs upon installation of type accepted stereophonic transmitting equipment and the necessary measuring equipment to determine that the stereophonic transmissions conform to the modulation characteristics specified in paragraphs (b) and (c) of this section. Stations transmitting stereophonic programs prior to March 21, 1994 may continue to do so until March 21, 1995 as long as they continue to comply with the rules in effect prior to March 21, 1994.

(b) The following limitations on the transmitted wave must be met to insure compliance with the occupied bandwidth limitations, compatibility with AM receivers using envelope detectors, and any applicable international agreements to which the FCC is a party:

(1) The transmitted wave must meet the occupied bandwidth specifications of §73.44 under all possible conditions of program modulation. Compliance with requirement shall be demonstrated either by the following specific modulation tests or other documented test procedures that are to be fully described in the application for type acceptance and the transmitting equipment instruction manual. (See §2.983(d)(8) and (j)).

(i) Main channel (L+R) under all conditions of amplitude modulations for the stereophonic system but not exceeding amplitude modulation on negative peaks of 100%.

(ii) Stereophonic (L−R) modulated with audio tones of the same amplitude at the transmitter input terminals as in paragraph (b)(i) of this section but with the phase of either the L or R channel reversed.

(iii) Left and Right Channel only, under all conditions of modulation for the stereophonic system in use but not exceeding amplitude modulation on negative peaks of 100%.

(c) Effective on December 20, 1994, stereophonic transmissions shall conform to the following additional modulation characteristics:

(1) The audio response of the main (L+R) channel shall conform to the requirements of the ANSI/EIA-549-1988, NRSC-1 AM Preemphasis/Deemphasis and Broadcast Transmission Bandwidth Specifications (NRSC-1).

(2) The left and right channel audio signals shall conform to frequency response limitations dictated by ANSI/EIA-549-1988.

(3) The stereophonic difference (L−R) information shall be transmitted by varying the phase of the carrier in accordance with the following relationship:

eCFR graphic er20de93.000.gif

View or download PDF

where:

L(t)=audio signal left channel,

R(t)=audio signal right channel,

m=modulation factor, and

mpeak(L(t)+R(t))=1 for 100% amplitude modulation,

mpeak(L(t)−R(t))=1 for 100% phase modulation.

(4) The carrier phase shall advance in a positive direction when a left channel signal causes the transmitter envelope to be modulated in a positive direction. The carrier phase shall likewise retard (negative phase change) when a right channel signal causes the transmitter envelope to be modulated in a positive direction. The phase modulation shall be symmetrical for the condition of difference (L−R) channel information sent without the presence of envelope modulation.

(5) Maximum angular modulation, which occurs on negative peaks of the left or right channel with no signal present on the opposite channel (L(t)=−0.75, R(t)=0, or R(t)=−0.75, L(t)=0) shall not exceed 1.25 radians.

(6) A peak phase modulation of +/−0.785 radians under the condition of difference (L−R) channel modulation and the absence of envelope (L+R) modulation and pilot signal shall represent 100% modulation of the difference channel.

(7) The composite signal shall contain a pilot tone for indication of the presence of stereophonic information. The pilot tone shall consist of a 25 Hz tone, with 3% or less total harmonic distortion and a frequency tolerance of +/− 0.1 H2, which modulates the carrier phase +/− 0.05 radians peak, corresponding to 5% L−R modulation when no other modulation is present. The injection level shall be 5%, with a tolerance of +1, −1%.

(8) The composite signal shall be described by the following expression:

eCFR graphic er20de93.001.gif

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where:

A=the unmodulated carrier voltage

m=the modulation index

Csn=the magnitude of the nth term of the sum signal

Cdn=the magnitude of the nth term of the difference signal

ωsn=the nth order angular velocity of the sum signal

ωdn=the nth order angular velocity of the difference signal

ωc=the angular velocity of the carrier

eCFR graphic er20de93.002.gif

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Asn and Bsn are the nth sine and cosine coefficients of Csn

Adn and Bdn are the nth sine and cosine coefficients of Cdn

[58 FR 66301, Dec. 20, 1993]

§73.132   Territorial exclusivity.

No licensee of an AM broadcast station shall have any arrangement with a network organization which prevents or hinders another station serving substantially the same area from broadcasting the network's programs not taken by the former station, or which prevents or hinders another station serving a substantially different area from broadcasting any program of the network organization: Provided, however, That this section does not prohibit arrangements under which the station is granted first call within its primary service area upon the network's programs. The term “network organization” means any organization originating program material, with or without commercial messages, and furnishing the same to stations interconnected so as to permit simultaneous broadcast by all or some of them. However, arrangements involving only stations under common ownership, or only the rebroadcast by one station or programming from another with no compensation other than a lump-sum payment by the station rebroadcasting, are not considered arrangements with a network organization. The term “arrangement” means any contract, arrangement or understanding, expressed or implied.

[42 FR 16422, Mar. 28, 1977]

§73.150   Directional antenna systems.

(a) For each station employing a directional antenna, all determinations of service provided and interference caused shall be based on the inverse distance fields of the standard radiation pattern for that station. (As applied to nighttime operation the term “standard radiation pattern” shall include the radiation pattern in the horizontal plane, and radiation patterns at angles above this plane.)

(1) Parties submitting directional antenna patterns pursuant to this section and §73.152 (Modified standard pattern) must submit patterns which are tabulated and plotted in units of millivolts per meter at 1 kilometer.

Note: Applications for new stations and for changes (both minor and major) in existing stations must use a standard pattern.

(b) The following data shall be submitted with an application for authority to install a directional antenna:

(1) The standard radiation pattern for the proposed antenna in the horizontal plane, and where pertinent, tabulated values for the azimuthal radiation patterns for angles of elevation up to and including 60 degrees, with a separate section for each increment of 5 degrees.

(i) The standard radiation pattern shall be based on the theoretical radiation pattern. The theoretical radiation pattern shall be calculated in accordance with the following mathematical expression:

eCFR graphic ec13no91.014.gif

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where:

E(φ,θ)th Represents the theoretical inverse distance fields at one kilometer for the given azimuth and elevation.

k   Represents the multiplying constant which determines the basic pattern size. It shall be chosen so that the effective field (RMS) of the theoretical pattern in the horizontal plane shall be no greater than the value computed on the assumption that nominal station power (see §73.14) is delivered to the directional array, and that a lumped loss resistance of one ohm exists at the current loop of each element of the array, or at the base of each element of electrical height lower than 0.25 wavelength, and no less than the value required by §73.189(b)(2) of this part for a station of the class and nominal power for which the pattern is designed.

n   Represents the number of elements (towers) in the directional array.

i   Represents the ith element in the array.

Fi   Represents the field ratio of the ith element in the array.

θ   Represents the vertical elevation angle measured from the horizontal plane.

fi(θ) represents the vertical plane radiation characteristic of the ith antenna. This value depends on the tower height, as well as whether the tower is top-loaded or sectionalized. The various formulas for computing fi(θ) are given in §73.160.

Si   Represents the electrical spacing of the ith tower from the reference point.

φi   Represents the orientation (with respect to true north) of the ith tower.

φ   Represents the azimuth (with respect to true north).

ψi   Represents the electrical phase angle of the current in the ith tower.

The standard radiation pattern shall be constructed in accordance with the following mathematical expression:

eCFR graphic ec01mr91.063.gif

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where:

E(φ,θ)std represents the inverse distance fields at one kilometer which are produced by the directional antenna in the horizontal and vertical planes. E(φ,θ)th represents the theoretical inverse distance fields at one kilometer as computed in accordance with Eq. 1, above.

Q is the greater of the following two quantities: 0.025g(θ) Erss or 10.0g(θ) √ PkW

where:

g(θ) is the vertical plane distribution factor, f(θ), for the shortest element in the array (see Eq. 2, above; also see §73.190, Figure 5). If the shortest element has an electrical height in excess of 0.5 wavelength, g(θ) shall be computed as follows:

eCFR graphic ec01mr91.064.gif

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Erss is the root sum square of the amplitudes of the inverse fields of the elements of the array in the horizontal plane, as used in the expression for E(φ,θ)th (see Eq. 1, above), and is computed as follows:

eCFR graphic ec01mr91.065.gif

View or download PDF

PkW is the nominal station power expressed in kilowatts, see §73.14. If the nominal power is less than one kilowatt, PkW=1.

(ii) Where the orthogonal addition of the factor Q to E(φ,θ)th results in a standard pattern whose minimum fields are lower than those found necessary or desirable, these fields may be increased by appropriate adjustment of the parameters of E(φ,θ)th.

(2) All patterns shall be computed for integral multiples of five degrees, beginning with zero degrees representing true north, and, shall be plotted to the largest scale possible on unglazed letter-size paper (main engraving approximately 7×10) using only scale divisions and subdivisions of 1,2,2.5, or 5 times 10nth. The horizontal plane pattern shall be plotted on polar coordinate paper, with the zero degree point corresponding to true north. Patterns for elevation angles above the horizontal plane may be plotted in polar or rectangular coordinates, with the pattern for each angle of elevation on a separate page. Rectangular plots shall begin and end at true north, with all azimuths labelled in increments of not less than 20 degrees. If a rectangular plot is used, the ordinate showing the scale for radiation may be logarithmic. Such patterns for elevation angles above the horizontal plane need be submitted only upon specific request by Commission staff. Minor lobe and null detail occurring between successive patterns for specific angles of elevation need not be submitted. Values of field strength on any pattern less than ten percent of the maximum field strength plotted on that pattern shall be shown on an enlarged scale. Rectangular plots with a logarithmic ordinate need not utilize an expanded scale unless necessary to show clearly the minor lobe and null detail.

(3) The effective (RMS) field strength in the horizontal plane of E(φ,θ)std, E(φ,θ)th and the root-sum-square (RSS) value of the inverse distance fields of the array elements at 1 kilometer, derived from the equation for E(φ,θ)th. These values shall be tabulated on the page on which the horizontal plane pattern is plotted, which shall be specifically labelled as the Standard Horizontal Plane Pattern.

(4) Physical description of the array, showing:

(i) Number of elements.

(ii) Type of each element (i.e., guyed or self-supporting, uniform cross section or tapered (specifying base dimensions), grounded or insulated, etc.)

(iii) Details of top loading, or sectionalizing, if any.

(iv) Height of radiating portion of each element in feet (height above base insulator, or base, if grounded).

(v) Overall height of each element above ground.

(vi) Sketch of antenna site, indicating its dimensions, the location of the antenna elements, thereon, their spacing from each other, and their orientation with respect to each other and to true north, the number and length of the radials in the ground system about each element, the dimensions of ground screens, if any, and bonding between towers and between radial systems.

(5) Electrical description of the array, showing:

(i) Relative amplitudes of the fields of the array elements.

(ii) Relative time phasing of the fields of the array elements in degrees leading [+] or lagging [−].

(iii) Space phasing between elements in degrees.

(iv) Where waiver of the content of this section is requested or upon request of the Commission staff, all assumptions made and the basis therefor, particularly with respect to the electrical height of the elements, current distribution along elements, efficiency of each element, and ground conductivity.

(v) Where waiver of the content of this section is requested, or upon request of the Commission staff, those formulas used for computing E(φ,θ)th and E(φ,θ)std. Complete tabulation of final computed data used in plotting patterns, including data for the determination of the RMS value of the pattern, and the RSS field of the array.

(6) The values used in specifying the parameters which describe the array must be specified to no greater precision than can be achieved with available monitoring equipment. Use of greater precision raises a rebuttable presumption of instability of the array. Following are acceptable values of precision; greater precision may be used only upon showing that the monitoring equipment to be installed gives accurate readings with the specified precision.

(i) Field Ratio: 3 significant figures.

(ii) Phasing: to the nearest 0.1 degree.

(iii) Orientation (with respect to a common point in the array, or with respect to another tower): to the nearest 0.1 degree.

(iv) Spacing (with respect to a common point in the array, or with respect to another tower): to the nearest 0.1 degree.

(v) Electrical Height (for all parameters listed in Section 73.160): to the nearest 0.1 degree.

(vi) Theoretical RMS (to determine pattern size): 4 significant figures.

(vii) Additional requirements relating to modified standard patterns appear in §73.152(c)(3) and (c)(4).

(7) Any additional information required by the application form.

(c) Sample calculations for the theoretical and standard radiation follow. Assume a five kilowatt (nominal power) station with a theoretical RMS of 685 mV/m at one kilometer. Assume that it is an in-line array consisting of three towers. Assume the following parameters for the towers:

TowerField ratioRelative phasingRelative spacingRelative orientation
11.0−128.50.00.0
21.890.0110.0285.0
31.0128.5220.0285.0

Assume that tower 1 is a typical tower with an electrical height of 120 degrees. Assume that tower 2 is top-loaded in accordance with the method described in §73.160(b)(2) where A is 120 electrical degrees and B is 20 electrical degrees. Assume that tower 3 is sectionalized in accordance with the method described in §73.160(b)(3) where A is 120 electrical degrees, B is 20 electrical degrees, C is 220 electrical degrees, and D is 15 electrical degrees.

The multiplying constant will be 323.6.

Following is a tabulation of part of the theoretical pattern:

Azimuth03060Vertical angle
015.9862.4968.20
1051225.30819.79234.54
2350.4318.4634.56
24782.6251.5226.38

If we further assume that the station has a standard pattern, we find that Q, for θ=0, is 22.36.

Following is a tabulation of part of the standard pattern:

Azimuth03060Vertical angle
028.8668.0572.06
1051286.78860.97246.41
23523.4826.5037.18
24789.8757.0328.87

The RMS of the standard pattern in the horizontal plane is 719.63 mV/m at one kilometer.

[36 FR 919, Jan. 20, 1971, as amended at 37 FR 529, Jan. 13, 1972; 41 FR 24134, June 15, 1976; 46 FR 11991, Feb. 12, 1981; 48 FR 24384, June 1, 1983; 51 FR 2707, Jan. 21, 1986; 52 FR 36877, Oct. 1, 1987; 56 FR 64861, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

§73.151   Field strength measurements to establish performance of directional antennas.

The performance of a directional antenna may be verified either by field strength measurement or by computer modeling and sampling system verification.

(a) In addition to the information required by the license application form, the following showing must be submitted to establish, for each mode of directional operation, that the effective measured field strength (RMS) at 1 kilometer (km) is not less than 85 percent of the effective measured field strength (RMS) specified for the standard radiation pattern, or less than that specified in §73.189(b) for the class of station involved, whichever is the higher value, and that the measured field strength at 1 km in any direction does not exceed the field shown in that direction on the standard radiation pattern for that mode of directional operation:

(1) A tabulation of inverse field strengths in the horizontal plane at 1 km, as determined from field strength measurements taken and analyzed in accordance with §73.186, and a statement of the effective measured field strength (RMS). Measurements shall be made in the following directions:

(i) Those specified in the instrument of authorization.

(ii) In major lobes. Generally, one radial is sufficient to establish a major lobe; however, additional radials may be required.

(iii) Along additional radials to establish the shape of the pattern. In the case of a relatively simple directional antenna pattern, a total of six radials is sufficient. If two radials would be more than 90° apart, then an additional radial must be specified within that arc. When more complicated patterns are involved, that is, patterns having several or sharp lobes or nulls, measurements shall be taken along as many as 12 radials to definitely establish the pattern(s). Pattern symmetry may be assumed for complex patterns which might otherwise require measurements on more than 12 radials.

(2) A tabulation of:

(i) The phase difference of the current in each element with respect to the reference element, and whether the current leads (+) or lags (−) the current in the reference element, as indicated by the station's antenna monitor.

(ii) The ratio of the amplitude of the radio frequency current in each element to the current in the reference element, as indicated on the station's antenna monitor.

(3) A monitoring point shall be established on each radial for which the construction permit specifies a limit. The following information shall be supplied for each monitoring point:

(i) Measured field strength.

(ii) An accurate and detailed description of each monitoring point. The description may include, but shall not be limited to, geographic coordinates determined with a Global Positioning System receiver.

(iii) Clear photographs taken with the field strength meter in its measuring position and with the camera so located that its field of view takes in as many pertinent landmarks as possible.

(b) For stations authorized to operate with simple directional antenna systems (e.g., two towers) in the 1605-1705 kHz band, the measurements to support pattern RMS compliance referred to in paragraphs (a)(1)(ii) and (a)(1)(iii) of this section are not required. In such cases, measured radials are required only in the direction of short-spaced allotments, or in directions specifically identified by the Commission.

(c) Computer modeling and sample system verification of modeled parameters to establish operation of a directional antenna consistent with the theoretical pattern. Each element of the directional array shall be modeled by use of a method of moments computer program, using the physical characteristics of each element to establish a model that does not violate any of the internal constraints of the computer program. Only arrays consisting of series-fed elements may have their performance verified by computer modeling and sample system verification.

(1) A matrix of impedance measurements at the base and/or feed point of each element in the array, with all other elements shorted and/or open circuited at their respective measurement locations, shall be made. The physical model of the individual antenna elements used in the computer program may be varied to match the measured impedance matrix, but the actual spacings and orientations of the array elements must be used. Towers may be modeled using individual vertical wires to represent them, or with multiple wires representing their leg and cross-member sections. The resulting model description (consisting of the length, radius, and number of segments of each wire for arrays using vertical wire sections to represent the towers, or the length, end-point coordinates, and radius of each wire used to represent leg and cross-member sections for arrays using detailed tower structure representations) as well as the assumed input feed and base region stray reactances shall be used to generate the drive impedances and sample system parameter values for the operating directional antenna pattern parameters.

(i) For arrays using vertical wires to represent each tower, the radii of cylinders shall be no less than 80 percent and no more than 150 percent of the radius of a circle with a circumference equal to the sum of the widths of the tower sides.

(ii) For arrays using multiple wires to represent leg and cross-member sections, the individual legs of the tower may be modeled at their actual diameters with appropriate interconnecting segments representing cross-members at regular intervals.

(iii) No less than one segment for each 10 electrical degrees of the tower's physical height shall be used for each element in the array.

(iv) Base calculations shall be made for a reference point at ground level or within one electrical degree elevation of the actual feed point.

(v) For uniform cross-section towers represented by vertical wires, each wire used for a given tower shall be between 75 to 125 percent of the physical length represented.

(vi) For self-supporting towers, stepped-radius wire sections may be employed to simulate the physical tower's taper, or the tower may be modeled with individual wire sections representing the legs and cross members.

(vii) The lumped series inductance of the feed system between the output port of each antenna tuning unit and the associated tower shall be no greater than 10 µH unless a measured value from the measurement point to the tower base with its insulator short circuited is used.

(viii) The shunt capacitance used to model base region effects shall be no greater than 250 pF unless the measured or manufacturer's stated capacitance for each device other than the base insulator is used. The total capacitance of such devices shall be limited such that in no case will their total capacitive reactance be less than five times the magnitude of the tower base operating impedance without their effects being considered.

(ix) The orientation and distances among the individual antenna towers in the array shall be confirmed by a post-construction certification by a land surveyor (or, where permitted by local regulation, by an engineer) licensed or registered in the state or territory where the antenna system is located.

(2)(i) The computer model, once verified by comparison with the measured base impedance matrix data, shall be used to determine the appropriate antenna monitor parameters. The moment method modeled parameters shall be established by using the verified moment method model to produce tower current distributions that, when numerically integrated and normalized to the reference tower, are identical to the specified field parameters of the theoretical directional antenna pattern. The samples used to drive the antenna monitor may be current transformers or voltage sampling devices at the outputs of the antenna matching networks or sampling loops located on the towers. If sample loops are used, they shall be located at the elevation where the current in the tower would be at a minimum if the tower were detuned in the horizontal plane, as determined by the moment method model parameters used to determine the antenna monitor parameters. Sample loops may be employed only when the towers are identical in cross-sectional structure, including both leg and cross member characteristics; if the towers are of unequal height, the sample loops shall be mounted identically with respect to tower cross members at the appropriate elevations above the base insulator. If the tower height used in the model is other than the physical height of the tower, the sampling loop shall be located at a height that is the same fraction of the total tower height as the minimum in tower current with the tower detuned in the model. Sample lines from the sensing element to the antenna monitor must be equal in both length (within one electrical degree) and characteristic impedance (within two ohms), as established by impedance measurements, including at the open-circuit resonant frequency closest to carrier frequency to establish length, at frequencies corresponding to odd multiples of 18 wavelength immediately above and below the open circuit resonant frequency closest to carrier frequency, while open circuited, to establish characteristic impedance, and at carrier frequency or, if necessary, at nearby frequencies where the magnitude of the measured impedance is no greater than 200 ohms with the sampling devices connected. Samples may be obtained from current transformers at the output of the antenna coupling and matching equipment for base-fed towers whose actual electrical height is 120 degrees or less, or greater than 190 electrical degrees. Samples may be obtained from base voltage sampling devices at the output of the antenna coupling and matching equipment for base-fed towers whose actual electrical height is greater than 105 degrees. Samples obtained from sample loops located as described above can be used for any height of tower. For towers using base current or base voltage sampling derived at the output of the antenna coupling and matching equipment, the sampling devices shall be disconnected and calibrated by measuring their outputs with a common reference signal (a current through them or a voltage across them, as appropriate) and the calibration must agree within the manufacturer's specifications. A complete description of the sampling system, including the results of the measurements described in this paragraph, shall be submitted with the application for license.

(ii) Proper adjustment of an antenna pattern shall be determined by correlation between the measured antenna monitor sample indications and the parameters calculated by the method of moments program, and by correlation between the measured matrix impedances for each tower and those calculated by the method of moments program. The antenna monitor sample indications must be initially adjusted to agree with the moment method model within ±5 percent for the field ratio and ±3 degrees in phase. The measured matrix impedances must agree with the moment method model within ±2 ohms and ±4 percent for resistance and reactance.

(3) Reference field strength measurement locations shall be established in directions of pattern minima and maxima. On each radial corresponding to a pattern minimum or maximum, there shall be at least three measurement locations. The field strength shall be measured at each reference location at the time of the proof of performance. The license application shall include the measured field strength values at each reference point, along with a description of each measurement location, including GPS coordinates and datum reference.

[36 FR 919, Jan. 20, 1971, as amended at 42 FR 36828, July 18, 1977; 49 FR 23348, June 6, 1984; 50 FR 32416, Aug. 12, 1985; 56 FR 64862, Dec. 12, 1991; 63 FR 33876, June 22, 1998; 66 FR 20756, Apr. 25, 2001; 73 FR 64561, Oct. 30, 2008]

§73.152   Modification of directional antenna data.

(a) If, after construction and final adjustment of a directional antenna, a measured inverse distance field in any direction exceeds the field shown on the standard radiation pattern for the pertinent mode of directional operation, an application shall be filed, specifying a modified standard radiation pattern and/or such changes as may be required in operating parameters so that all measured effective fields will be contained within the modified standard radiation pattern. Permittees may also file an application specifying a modified standard radiation pattern, even when measured radiation has not exceeded the standard pattern, in order to allow additional tolerance for monitoring point limits.

(b) If, following a partial proof of performance, a licensee discovers that radiation exceeds the standard pattern on one or more radials because of circumstances beyond the licensee's control, a modified standard pattern may be requested. The licensee shall submit, concurrently, Forms 301-AM and 302-AM. Form 301-AM shall include an exhibit demonstrating that no interference would result from the augmentation. Form 302-AM shall include the results of the partial proof, along with full directional and nondirectional measurements on the radial(s) to be augmented, including close-in points and a determination of the inverse distance field in accordance with §73.186.

(c) Normally, a modified standard pattern is not acceptable at the initial construction permit stage, before a proof-of-performance has been completed. However, in certain cases, where it can be shown that modification is necessary, a modified standard pattern will be acceptable at the initial construction permit stage. Following is a non-inclusive list of items to be considered in determining whether a modification is acceptable at the initial construction permit stage:

(1) When the proposed pattern is essentially the same as an existing pattern at the same antenna site. (e.g., A DA-D station proposing to become a DA-1 station.)

(2) Excessive reradiating structures, which should be shown on a plat of the antenna site and surrounding area.

(3) Other environmental factors; they should be fully described.

(4) Judgment and experience of the engineer preparing the engineering portion of the application. This must be supported with a full discussion of the pertinent factors.

(d) The following general principles shall govern the situations in paragraphs (a), (b), and (c) in this section:

(1) Where a measured field in any direction will exceed the authorized standard pattern, the license application may specify the level at which the input power to the antenna shall be limited to maintain the measured field at a value not in excess of that shown on the standard pattern, and shall specify the common point current corresponding to this power level. This value of common point current will be specified on the license for that station.

(2) Where any excessive field does not result in objectionable interference to another station, a modification of construction permit application may be submitted with a modified standard pattern encompassing all augmented fields. The modified standard pattern shall supersede the previously submitted standard radiation pattern for that station in the pertinent mode of directional operation. Following are the possible methods of creating a modified standard pattern:

(i) The modified pattern may be computed by making the entire pattern larger than the original pattern (i.e., have a higher RMS value) if the measured fields systematically exceed the confines of the original pattern. The larger pattern shall be computed by using a larger multiplying constant, k, in the theoretical pattern equation (Eq. 1) in §73.150(b)(1).

(ii) Where the measured field exceeds the pattern in discrete directions, but objectionable interference does not result, the pattern may be expanded over sectors including these directions. When this “augmentation” is desired, it shall be achieved by application of the following equation:

E(φ,θ)aug = √{ E(φ,θ)std }2 + A{g(θ) cos (180 DA/S  }2

where:

E(φ,θ)std is the standard pattern field at some particular azimuth and elevation angle, before augmentation, computed pursuant to Eq. 2, §73.150(b)(1)(i).

E(φ,θ)aug. is the field in the direction specified above, after augmentation.

A=E(φ, O)2aug−E(φ, O)2std in which φ is the central azimuth of augmentation. E(φ, O)aug and E(φ, O)std are the fields in the horizontal plane at the central azimuth of augmentation.

Note: “A” must be positive, except during the process of converting non-standard patterns to standard patterns pursuant to the Report and Order in Docket No. 21473, and in making minor changes to stations with patterns developed during the conversion. However, even when “A” is negative, “A” cannot be so negative that E(φ,α)aug is less than E(φ,θ)th at any azimuth or vertical elevation angle.

g(θ) is defined in §73.150(b)(1)(i).

S is the angular range, or “span”, over which augmentation is applied. The span is centered on the central azimuth of augmentation. At the limits of the span, the augmented pattern merges into the unaugmented pattern. Spans may overlap.

DA is the absolute horizontal angle between the azimuth at which the augmented pattern value is being computed and the central azimuth of augmentation. (DA cannot exceed 1/2 S.)

In the case where there are spans which overlap, the above formula shall be applied repeatedly, once for each augmentation, in ascending order of central azimuth of augmentation, beginning with zero degrees representing true North. Note that, when spans overlap, there will be, in effect, an augmentation of an augmentation. And, if the span of an earlier augmentation overlaps the central azimuth of a later augmentation, the value of “A” for the later augmentation will be different than the value of “A” without the overlap of the earlier span.

(iii) A combination of paragraphs (d)(2)(i) and (d)(2)(ii), of this section, with (d)(2)(i) being applied before (d)(2)(ii) is applied.

(iv) Where augmentation is allowable under the terms of this section, the requested amount of augmentation shall be centered upon the measured radial and shall not exceed the following:

(A) The actual measured inverse distance field value, where the radial does not involve a required monitoring point.

(B) 120% of the actual measured inverse field value, where the radial has a monitoring point required by the instrument of authorization.

Whereas some pattern smoothing can be accommodated, the extent of the requested span(s) shall be minimized and in no case shall a requested augmentation span extend to a radial azimuth for which the analyzed measurement data does not show a need for augmentation.

(3) A Modified Standard Pattern shall be specifically labeled as such, and shall be plotted in accordance with the requirements of paragraph (b)(2) of §73.150. The effective (RMS) field strength in the horizontal plane of E(φ,α)std, E(φ,α)th, and the root sum square (RSS) value of the inverse fields of the array elements (derived from the equation for E(φ,α)th), shall be tabulated on the page on which the horizontal plane pattern is plotted. Where sector augmentation has been employed in designing the modified pattern, the direction of maximum augmentation (i.e., the central azimuth of augmentation) shall be indicated on the horizontal plane pattern for each augmented sector, and the limits of each sector shall also be shown. Field values within an augmented sector, computed prior to augmentation, shall be depicted by a broken line.

(4) There shall be submitted, for each modified standard pattern, complete tabulations of final computed data used in plotting the pattern. In addition, for each augmented sector, the central azimuth of augmentation, span, and radiation at the central azimuth of augmentation (E(φ,α)aug) shall be tabulated.

(5) The parameters used in computing the modified standard pattern shall be specified with realistic precision. Following is a list of the maximum acceptable precision:

(i) Central Azimuth of Augmentation: to the nearest 0.1 degree.

(ii) Span: to the nearest 0.1 degree.

(iii) Radiation at Central Azimuth of Augmentation: 4 significant figures.

(e) Sample calculations for a modified standard pattern follow. First, assume the existing standard pattern in §73.150(c). Then, assume the following augmentation parameters:

Augmentation numberCentral azimuthSpanRadiation at central azimuth
1110401,300
22405052
325010130

Following is a tabulation of part of the modified standard pattern:

Azimuth03060Vertical angle
028.8668.0572.06
1051,299.42872.14254.21
23539.0035.7438.71
247100.4766.6932.78

[46 FR 11992, Feb. 12, 1981, as amended at 56 FR 64862, Dec. 12, 1991; 66 FR 20756, Apr. 25, 2001]

§73.153   Field strength measurements in support of applications or evidence at hearings.

In the determination of interference, groundwave field strength measurements will take precedence over theoretical values, provided such measurements are properly taken and presented. When measurements of groundwave signal strength are presented, they shall be sufficiently complete in accordance with §73.186 to determine the field strength at 1 mile in the pertinent directions for that station. The antenna resistance measurements required by §73.186 need not be taken or submitted.

[44 FR 36037, June 20, 1979, as amended at 56 FR 64862, Dec. 12, 1991]

§73.154   AM directional antenna partial proof of performance measurements.

(a) A partial proof of performance consists of at least 8 field strength measurements made on each of the radials that includes a monitoring point. If the directional pattern has fewer than 4 monitored radials, the partial proof shall include measurements on those radials from the latest complete proof of performance which are adjacent to the monitored radials.

(b) The measurements are to be made within 3 to 15 kilometers from the center of the antenna array. When a monitoring point as designated on the station authorization lies on a particular radial, one of the measurements must be made at that point. One of the following methods shall be used for the partial proof:

(1) Measurement points shall be selected from the points measured in latest full proof of performance provided that the points can be identified with reasonable certainty, and that land development or other factors have not significantly altered propagation characteristics since the last full proof. At each point, the licensee shall measure directional field strength for comparison to either the directional or the nondirectional field strength measured at that point in the last full proof.

(2) In the event that a meaningful comparison to full proof measurements cannot be made, the licensee shall measure both directional and nondirectional field strength at eight points on each radial. The points need not be limited to those measured in the last full proof of performance.

(c) The results of the measurements are to be analyzed as follows. Either the arithmetic average or the logarithmic average of the ratios of the field strength at each measurement point to the corresponding field strength in the most recent complete proof of performance shall be used to establish the inverse distance fields. (The logarithmic average for each radial is the antilogarithm of the mean of the logarithms of the ratios of field strength (new to old) for each measurement location along a given radial). When new nondirectional measurements are used as the reference, as described in paragraph (b)(2) of this section, either the arithmetic or logarithmic averages of directional to nondirectional field strength on each radial shall be used in conjunction with the measured nondirectional field from the last proof to establish the inverse distance field.

(d) The result of the most recent partial proof of performance measurements and analysis is to be retained in the station records available to the FCC upon request. Maps showing new measurement points, i.e., points not measured in the last full proof, shall be associated with the partial proof in the station's records, and shall be provided to the FCC upon request.

[66 FR 20756, Apr. 25, 2001]

§73.155   Periodic directional antenna performance recertification.

A station licensed with a directional antenna pattern pursuant to a proof of performance using moment method modeling and internal array parameters as described in §73.151(c) shall recertify the performance of that directional antenna pattern at least once within every 24 month period.

(a) Measurements shall be made to verify the continuing integrity of the antenna monitor sampling system.

(1) For towers using base current or base voltage sampling derived at the output of the antenna coupling and matching equipment, the sampling devices shall be disconnected and calibrated by measuring their outputs with a common reference signal (a current through them or a voltage across them, as appropriate) and the calibration must agree with the manufacturer's specifications.

(2) For towers using base current or base voltage sampling derived at the output of the antenna coupling and matching equipment, sampling line measurements shall be made to verify the open-circuit resonant frequency closest to carrier frequency, to establish length, and also at frequencies corresponding to odd multiples of 18 wavelength immediately above and below the open-circuit resonant frequency closest to carrier frequency, while open circuited, to verify their characteristic impedance. The frequencies measured must be the same as were measured in the most recent proof of performance and must demonstrate that the sampling lines continue to meet the requirements of §73.151(c) with regard to their length and characteristic impedance.

(3) For towers having sampling loops, measurements shall be made at carrier frequency or, if necessary, at nearby frequencies where the magnitude of the measured impedance is no greater than 200 ohms with the sampling loops connected. The frequencies measured must be the same as were measured in the most recent proof of performance and the measured impedances must agree within ±2 ohms and ±4 percent resistance and reactance of the proof values.

(b) Field strength measurements shall be made at the reference field strength measurement locations that were established by the most recent proof of performance. If locations have become inaccessible or their readings contaminated by localized electromagnetic environmental changes, new locations that meet the requirements of the moment method proof of performance rules in §73.151(c)(3) shall be established to replace them.

(c) The results of the periodic directional antenna performance recertification measurements shall be retained in the station's public inspection file.

[73 FR 64562, Oct. 30, 2008]

§73.157   Antenna testing during daytime.

(a) The licensee of a station using a directional antenna during daytime or nighttime hours may, without further authority, operate during daytime hours with the licensed nighttime directional facilities or with a nondirectional antenna when conducting monitoring point field strength measurements or antenna proof of performance measurements.

(b) Operation pursuant to this section is subject to the following conditions:

(1) No harmful interference will be caused to any other station.

(2) The FCC may notify the licensee to modify or cease such operation to resolve interference complaints or when such action may appear to be in the public interest, convenience and necessity.

(3) Such operation shall be undertaken only for the purpose of taking monitoring point field strength measurements or antenna proof of performance measurements, and shall be restricted to the minimum time required to accomplish the measurements.

(4) Operating power in the nondirectional mode shall be adjusted to the same power as was utilized for the most recent nondirectional proof of performance covering the licensed facilities.

[50 FR 30947, July 31, 1985]

§73.158   Directional antenna monitoring points.

(a) When a licensee of a station using a directional antenna system finds that a field monitoring point, as specified on the station authorization, is no longer accessible or is unsuitable because of nearby construction or other disturbances to the measured field, an application to change the monitoring point location, including FCC Form 302-AM, is to be promptly submitted to the FCC in Washington, DC.

(1) If the monitoring point has become inaccessible or otherwise unsuitable, but there has been no significant construction or other change in the vicinity of the monitoring point which may affect field strength readings, the licensee shall select a new monitoring point from the points measured in the last full proof of performance. A recent field strength measurement at the new monitoring point shall also be provided.

(2) Alternatively, if changes in the electromagnetic environment have affected field strength readings at the monitoring point, the licensee shall submit the results of a partial proof of performance, analyzed in accordance with §73.154, on the affected radial.

(3) The licensee shall submit an accurate, written description of the new monitoring point in relation to nearby permanent landmarks.

(4) The licensee shall submit a photograph showing the new monitoring point in relation to nearby permanent landmarks that can be used in locating the point accurately at all times throughout the year. Do not use seasonal or temporary features in either the written descriptions or photographs as landmarks for locating field points.

(b) When the description of the monitoring point as shown on the station license is no longer correct due to road or building construction or other changes, the licensee must prepare and file with the FCC, in Washington, DC, a request for a corrected station license showing the new monitoring point description. The request shall include the information specified in paragraphs (a)(3) and (a)(4) of this section, and a copy of the station's current license. A copy of the description is to be posted with the existing station license.

[66 FR 20757, Apr. 25, 2001]

§73.160   Vertical plane radiation characteristics, f(θ).

(a) The vertical plane radiation characteristics show the relative field being radiated at a given vertical angle, with respect to the horizontal plane. The vertical angle, represented as θ, is 0 degrees in the horizontal plane, and 90 degrees when perpendicular to the horizontal plane. The vertical plane radiation characteristic is referred to as f(θ). The generic formula for f(θ) is:

f(θ)=E(θ)/E(O)

where:

E(θ) is the radiation from the tower at angle θ.

E(O) is the radiation from the tower in the horizontal plane.

(b) Listed below are formulas for f(θ) for several common towers.

(1) For a typical tower, which is not top-loaded or sectionalized, the following formula shall be used:

eCFR graphic ec13no91.015.gif

View or download PDF

where:

G is the electrical height of the tower, not including the base insulator and pier. (In the case of a folded unipole tower, the entire radiating structure's electrical height is used.)

(2) For a top-loaded tower, the following formula shall be used:

eCFR graphic ec13no91.016.gif

View or download PDF

where:

A is the physical height of the tower, in electrical degrees, and

B is the difference, in electrical degrees, between the apparent electrical height (G, based on current distribution) and the actual physical height.

G is the apparent electrical height: the sum of A and B; A+B.

See Figure 1 of this section.

eCFR graphic ec01mr91.066.gif

View or download PDF

(3) For a sectionalized tower, the following formula shall be used:

eCFR graphic ec13no91.017.gif

View or download PDF

where:

A is the physical height, in electrical degrees, of the lower section of the tower.

B is the difference between the apparent electrical height (based on current distribution) of the lower section of the tower and the physical height of the lower section of the tower.

C is the physical height of the entire tower, in electrical degrees.

D is the difference between the apparent electrical height of the tower (based on current distribution of the upper section) and the physical height of the entire tower. D will be zero if the sectionalized tower is not top-loaded.

G is the sum of A and B; A+B.

H is the sum of C and D; C+D.

Δ is the difference between H and A; H−A.

See Figure 2 of this section.

eCFR graphic ec01mr91.067.gif

View or download PDF

(c) One of the above f(θ) formulas must be used in computing radiation in the vertical plane, unless the applicant submits a special formula for a particular type of antenna. If a special formula is submitted, it must be accompanied by a complete derivation and sample calculations. Submission of values for f(θ) only in a tabular or graphical format (i.e., without a formula) is not acceptable.

(d) Following are sample calculations. (The number of significant figures shown here should not be interpreted as a limitation on the number of significant figures used in actual calculations.)

(1) For a typical tower, as described in paragraph (b)(1) of this section, assume that G=120 electrical degrees:

θf(θ)
01.0000
300.7698
600.3458

(2) For a top-loaded tower, as described in paragraph (b)(2) of this section, assume A=120 electrical degrees, B=20 electrical degrees, and G=140 electrical degrees, (120+20):

θf(θ)
01.0000
300.7364
600.2960

(3) For a sectionalized tower, as described in paragraph (b)(3) of this section, assume A=120 electrical degrees, B=20 electrical degrees, C=220 electrical degrees, D=15 electrical degrees, G=140 electrical degrees (120+20), H=235 electrical degrees (220+15), and Δ=115 electrical degrees (235−120):

θf(θ)
01.0000
300.5930
600.1423

[46 FR 11993, Feb. 12, 1981]

§73.182   Engineering standards of allocation.

(a) Sections 73.21 to 73.37, inclusive, govern allocation of facilities in the AM broadcast band 535-1705 kHz. §73.21 establishes three classes of channels in this band, namely, clear, regional and local. The classes and power of AM broadcast stations which will be assigned to the various channels are set forth in §73.21. The classifications of the AM broadcast stations are as follows:

(1) Class A stations operate on clear channels with powers no less than 10kW nor greater than 50 kW. These stations are designed to render primary and secondary service over an extended area, with their primary services areas protected from objectionable interference from other stations on the same and adjacent channels. Their secondary service areas are protected from objectionable interference from co-channel stations. For purposes of protection, Class A stations may be divided into two groups, those located in any of the contiguous 48 States and those located in Alaska in accordance with §73.25.

(i) The mainland U.S. Class A stations are those assigned to the channels allocated by §73.25. The power of these stations shall be 50 kW. The Class A stations in this group are afforded protection as follows:

(A) Daytime. To the 0.1 mV/m groundwave contour from stations on the same channel, and to the 0.5 mV/m groundwave contour from stations on adjacent channels.

(B) Nighttime. To the 0.5 mV/m-50% skywave contour from stations on the same channels.

(ii) Class A stations in Alaska operate on the channels allocated by §73.25 with a minimum power of 10 kW, a maximum power of 50 kW, and an antenna efficiency of 282 mV/m/kW at 1 kilometer. Stations operating on these channels in Alaska which have not been designated as Class A stations in response to licensee request will continue to be considered as Class B stations. During daytime hours a Class A station in Alaska is protected to the 100 µV/m groundwave contour from co-channel stations. During nighttime hours, a Class A station in Alaska is protected to the 100 µV/m-50 percent skywave contour from co-channel stations. The 0.5 mV/m groundwave contour is protected both daytime and nighttime from stations on adjacent channels.

Note: In the Report and Order in MM Docket No. 83-807, the Commission designated 15 stations operating on U.S. clear channels as Alaskan Class A stations. Eleven of these stations already have Alaskan Class A facilities and are to be protected accordingly. Permanent designation of the other four stations as Alaskan Class A is conditioned on their constructing minimum Alaskan Class A facilities no later than December 31, 1989. Until that date or until such facilities are obtained, these four stations shall be temporarily designated as Alaskan Class A stations, and calculations involving these stations should be based on existing facilities but with an assumed power of 10 kW. Thereafter, these stations are to be protected based on their actual Alaskan Class A facilities. If any of these stations does not obtain Alaskan Class A facilities in the period specified, it is to be protected as a Class B station based on its actual facilities. These four stations may increase power to 10 kW without regard to the impact on co-channel Class B stations. However, power increases by these stations above 10 kW (or by existing Alaskan Class A stations beyond their current power level) are subject to applicable protection requirements for co-channel Class B stations. Other stations not on the original list but which meet applicable requirements may obtain Alaskan Class A status by seeking such designation from the Commission. If a power increase or other change in facilities by a station not on the original list is required to obtain minimum Alaskan Class A facilities, any such application shall meet the interference protection requirements applicable to an Alaskan Class A proposal on the channel.

(2) Class B stations are stations which operate on clear and regional channels with powers not less than 0.25 kW nor more than 50 kW. These stations render primary service only, the area of which depends on their geographical location, power, and frequency. It is recommended that Class B stations be located so that the interference received from other stations will not limit the service area to a groundwave contour value greater than 2.0 mV/m nighttime and to the 0.5 mV/m groundwave contour daytime, which are the values for the mutual protection between this class of stations and other stations of the same class.

Note: See §§73.21(b)(1) and 73.26(b) concerning power restrictions and classifications relative to Class B, Class C, and Class D stations in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. Stations in the above-named places that are reclassified from Class C to Class B stations under §73.26(b) shall not be authorized to increase power to levels that would increase the nighttime interference-free limit of co-channel Class C stations in the conterminous United States.

(3) Class C stations operate on local channels, normally rendering primary service to a community and the suburban or rural areas immediately contiguous thereto, with powers not less than 0.25 kW, nor more than 1 kW, except as provided in §73.21(c)(1). Such stations are normally protected to the daytime 0.5 mV/m contour. On local channels the separation required for the daytime protection shall also determine the nighttime separation. Where directional antennas are employed daytime by Class C stations operating with more than 0.25 kW power, the separations required shall in no case be less than those necessary to afford protection, assuming nondirectional operation with 0.25 kW. In no case will 0.25 kW or greater nighttime power be authorized to a station unable to operate nondirectionally with a power of 0.25 kW during daytime hours. The actual nighttime limitation will be calculated. For nighttime protection purposes, Class C stations in the 48 contiguous United States may assume that stations in Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands operating on 1230, 1240, 1340, 1400, 1450, and 1490 kHz are Class C stations.

(4) Class D stations operate on clear and regional channels with daytime powers of not less than 0.25 kW (or equivalent RMS field of 141 mV/m at one kilometer if less than 0.25 kW) and not more than 50 kW. Class D stations that have previously received nighttime authority operate with powers of less than 0.25 kW (or equivalent RMS fields of less than 141 mV/m at one kilometer) are not required to provide nighttime coverage in accordance with §73.24(j) and are not protected from interference during nighttime hours. Such nighttime authority is permitted on the basis of full nighttime protection being afforded to all Class A and Class B stations.

(b) When a station is already limited by interference from other stations to a contour value greater than that normally protected for its class, the individual received limits shall be the established standard for such station with respect to interference from each other station.

(c) The four classes of AM broadcast stations have in general three types of service areas, i.e., primary, secondary and intermittent. (See §73.14 for the definitions of primary, secondary, and intermittent service areas.) Class A stations render service to all three areas. Class B stations render service to a primary area but the secondary and intermittent service areas may be materially limited or destroyed due to interference from other stations, depending on the station assignments involved. Class C and Class D stations usually have only primary service areas. Interference from other stations may limit intermittent service areas and generally prevents any secondary service to those stations which operate at night. Complete intermittent service may still be obtained in many cases depending on the station assignments involved.

(d) The groundwave signal strength required to render primary service is 2 mV/m for communities with populations of 2,500 or more and 0.5 mV/m for communities with populations of less than 2,500. See §73.184 for curves showing distance to various groundwave field strength contours for different frequencies and ground conductivities, and also see §73.183, “Groundwave signals.”

(e) A Class C station may be authorized to operate with a directional antenna during daytime hours providing the power is at least 0.25 kW. In computing the degrees of protection which such antenna will afford, the radiation produced by the directional antenna system will be assumed to be no less, in any direction, than that which would result from non-directional operation using a single element of the directional array, with 0.25 kW.

(f) All classes of broadcast stations have primary service areas subject to limitation by fading and noise, and interference from other stations to the contours set out for each class of station.

(g) Secondary service is provided during nighttime hours in areas where the skywave field strength, 50% or more of the time, is 0.5 mV/m or greater (0.1 mV/m in Alaska). Satisfactory secondary service to cities is not considered possible unless the field strength of the skywave signal approaches or exceeds the value of the groundwave field strength that is required for primary service. Secondary service is subject to some interference and extensive fading whereas the primary service area of a station is subject to no objectionable interference or fading. Only Class A stations are assigned on the basis of rendering secondary service.

Note: Standards have not been established for objectionable fading because of the relationship to receiver characteristics. Selective fading causes audio distortion and signal strength reduction below the noise level, objectionable characteristics inherent in many modern receivers. The AVC circuits in the better designed receivers generally maintain the audio output at a sufficiently constant level to permit satisfactory reception during most fading conditions.

(h) Intermittent service is rendered by the groundwave and begins at the outer boundary of the primary service area and extends to a distance where the signal strength decreases to a value that is too low to provide any service. This may be as low as a few µV/m in certain areas and as high as several millivolts per meter in other areas of high noise level, interference from other stations, or objectionable fading at night. The intermittent service area may vary widely from day to night and generally varies over shorter intervals of time. Only Class A stations are protected from interference from other stations to the intermittent service area.

(i) Broadcast stations are licensed to operate unlimited time, limited time, daytime, share time, and specified hours. (See §§73.1710, 73.1725, 73.1720, 73.1715, and 73.1730.) Applications for new stations shall specify unlimited time operation only.

(j) Section 73.24 sets out the general requirements for modifying the facilities of a licensed station and for establishing a new station. Sections 73.24(b) and 73.37 include interference related provisions that be considered in connection with an application to modify the facilities of an existing station or to establish a new station. Section 73.30 describes the procedural steps required to receive an authorization to operate in the 1605-1705 kHz band.

(k) Objectionable nighttime interference from a broadcast station occurs when, at a specified field strength contour with respect to the desired station, the field strength of an undesired station (co-channel or first adjacent channel, after application of proper protection ratio) exceeds for 10% or more of the time the values set forth in these standards. The value derived from the root-sum-square of all interference contributions represents the extent of a station's interference-free coverage.

(1) With respect to the root-sum-square (RSS) values of interfering field strengths referred to in this section, calculation of nighttime interference-free service is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum, excluding those signals which are less than 50% of the RSS values of the higher signals already included.

(2) With respect to the root-sum-square values of interfering field strengths referred to in this section, calculation of nighttime interference for non-coverage purposes is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum, excluding those signals which are less than 25% of the RSS values of the higher signals already included.

(3) With respect to the root-sum-square values of interfering field strengths referred to in this section, calculation is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum. The 0% exclusion method applies only to the determination of an improvement factor value for evaluating a station's eligibility for migration to the band 1605-1705 kHz.

(4) The RSS value will not be considered to be increased when a new interfering signal is added which is less than the appropriate exclusion percentage as applied to the RSS value of the interference from existing stations, and which at the same time is not greater than the smallest signal included in the RSS value of interference from existing stations.

(5) It is recognized that application of the above “50% exclusion” method (or any exclusion method using a per cent value greater than zero) of calculating the RSS interference may result in some cases in anomalies wherein the addition of a new interfering signal or the increase in value of an existing interfering signal will cause the exclusion of a previously included signal and may cause a decrease in the calculated RSS value of interference. In order to provide the Commission with more realistic information regarding gains and losses in service (as a basis for determination of the relative merits of a proposed operation) the following alternate method for calculating the proposed RSS values of interference will be employed wherever applicable.

(6) In the cases where it is proposed to add a new interfering signal which is not less than 50% (or 25%, depending on which study is being performed) of the RSS value of interference from existing stations or which is greater that the smallest signal already included to obtain this RSS value, the RSS limitation after addition of the new signal shall be calculated without excluding any signal previously included. Similarly, in cases where it is proposed to increase the value of one of the existing interfering signals which has been included in the RSS value, the RSS limitation after the increase shall be calculated without excluding the interference from any source previously included.

(7) If the new or increased signal proposed in such cases is ultimately authorized, the RSS values of interference to other stations affected will thereafter be calculated by the “50% exclusion” (or 25% exclusion, depending on which study is being performed) method without regard to this alternate method of calculation.

(8) Examples of RSS interference calculations:

(i) Existing interferences:

Station No. 1—1.00 mV/m.

Station No. 2—0.60 mV/m.

Station No. 3—0.59 mV/m.

Station No. 4—0.58 mV/m.

The RSS value from Nos. 1, 2 and 3 is 1.31 mV/m; therefore interference from No. 4 is excluded for it is less than 50% of 1.31 mV/m.

(ii) Station A receives interferences from:

Station No. 1—1.00 mV/m.

Station No. 2—0.60 mV/m.

Station No. 3—0.59 mV/m.

It is proposed to add a new limitation, 0.68 mV/m. This is more than 50% of 1.31 mV/m, the RSS value from Nos. 1, 2 and 3. The RSS value of Station No. 1 and of the proposed station would be 1.21 m/Vm which is more than twice as large as the limitation from Station No. 2 or No. 3. However, under the above provision the new signal and the three existing interferences are nevertheless calculated for purposes of comparative studies, resulting in an RSS value of 1.47 mV/m. However, if the proposed station is ultimately authorized, only No. 1 and the new signal are included in all subsequent calculations for the reason that Nos. 2 and 3 are less than 50% of 1.21 mV/m, the RSS value of the new signal and No. 1.

(iii) Station A receives interferences from:

Station No. 1—1.00 mV/m.

Station No. 2—0.60 mV/m.

Station No. 3—0.59 mV/m.

No. 1 proposes to increase the limitation it imposes on Station A to 1.21 mV/m. Although the limitations from stations Nos. 2 and 3 are less than 50% of the 1.21 mV/m limitation, under the above provision they are nevertheless included for comparative studies, and the RSS limitation is calculated to be 1.47 mV/m. However, if the increase proposed by Station No. 1 is authorized, the RSS value then calculated is 1.21 mV/m because Stations Nos. 2 and 3 are excluded in view of the fact that the limitations they impose are less than 50% of 1.21 mV/m.

Note: The principles demonstrated in the previous examples for the calculation of the 50% exclusion method also apply to calculations using the 25% exclusion method after appropriate adjustment.

(l) Objectionable nighttime interference from a station shall be considered to exist to a station when, at the field strength contour specified in paragraph (q) of this section with respect to the class to which the station belongs, the field strength of an interfering station operating on the same channel or on a first adjacent channel after signal adjustment using the proper protection ratio, exceeds for 10% or more of the time the value of the permissible interfering signal set forth opposite such class in paragraph (q) of this section.

(m) For the purpose of estimating the coverage and the interfering effects of stations in the absence of field strength measurements, use shall be made of Figure 8 of §73.190, which describes the estimated effective field (for 1 kW power input) of simple vertical omnidirectional antennas of various heights with ground systems having at least 120 quarter-wavelength radials. Certain approximations, based on the curve or other appropriate theory, may be made when other than such antennas and ground systems are employed, but in any event the effective field to be employed shall not be less than the following:

Class of stationEffective field (at 1 km)
All Class A (except Alaskan)362 mV/m.
Class A (Alaskan), B and D282 mV/m.
Class C241 mV/m.

Note (1): When a directional antenna is employed, the radiated signal of a broadcasting station will vary in strength in different directions, possibly being greater than the above values in certain directions and less in other directions depending upon the design and adjustment of the directional antenna system. To determine the interference in any direction, the measured or calculated radiated field (unattenuated field strength at 1 kilometer from the array) must be used in conjunction with the appropriate propagation curves. (See §73.185 for further discussion and solution of a typical directional antenna case.)

Note (2): For Class B stations in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands, 241 mV/m shall be used.

(n) The existence or absence of objectionable groundwave interference from stations on the same or adjacent channels shall be determined by actual measurements made in accordance with the method described in §73.186, or in the absence of such measurements, by reference to the propagation curves of §73.184. The existence or absence of objectionable interference due to skywave propagation shall be determined by reference to Formula 2 in §73.190.

(o) Computation of skywave field strength values:—(1) Fifty percent skywave field strength values (clear channel). In computing the fifty percent skywave field strength values of a Class A clear channel station, use shall be made of Formula 1 of §73.190, entitled “Skywave Field Strength” for 50 percent of the time.

(2) Ten percent skywave field strength values. In computing the 10% skywave field strength for stations on a single signal or an RSS basis, Formula 2 in §73.190 shall be used.

(3) Determination of angles of departure. In calculating skywave field strength for stations on all channels, the pertinent vertical angle shall be determined by use of the formula in §73.190(d).

(p) The distance to any specified groundwave field strength contour for any frequency may be determined from the appropriate curves in §73.184 entitled “Ground Wave Field Strength vs. Distance.”

(q) Normally protected service contours and permissible interference signals for broadcast stations are as follows (for Class A stations, see also paragraph (a) of this section):

Class of stationClass of channel usedSignal strength contour of area protected from objectionable interference1(µV/m)Permissible interfering signal (µV/m)
Day2NightDay2Night3
AClearSC 100SC 500 50% SWSC 5SC 25
   AC 500AC 500 GWAC 250AC 250
A (Alaskan)......doSC 100SC 100 50% SWSC 5SC 5
   AC 500AC 500 GWAC 250AC 250
BClear500200022525
   RegionalAC 250250
CLocal500No presc.4SC25Not presc.
DClear500Not prescSC 25Not presc.
   RegionalAC 250

1When a station is already limited by interference from other stations to a contour of higher value than that normally protected for its class, this higher value contour shall be the established protection standard for such station. Changes proposed by Class A and B stations shall be required to comply with the following restrictions. Those interferers that contribute to another station's RSS using the 50% exclusion method are required to either reduce their contributions to that RSS by 10%, or to a level at which their contributions no longer enter into the 50% RSS value, whichever is the lesser amount of reduction. Those interferers that contribute to a station's RSS using the 25% exclusion method but do not contribute to that station's RSS using the 50% exclusion method may make changes not to exceed their present contribution. Interferers not included in a station's RSS using the 25% exclusion method are permitted to increase radiation as long as the 25% exclusion threshold is not equalled or exceeded. In no case will a reduction be required that would result in a contributing value that is below the pertinent value specified in the table. This note does not apply to Class C stations; or to the protection of Class A stations which are normally protected on a single signal, non-RSS basis.

2Groundwave.

3Skywave field strength for 10 percent or more of the time.

4During nighttime hours, Class C stations in the contiguous 48 States may treat all Class B stations assigned to 1230, 1240, 1340, 1400, 1450 and 1490 kHz in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands as if they were Class C stations.

Note: SC=Same channel; AC=Adjacent channel; SW=Skywave; GW=Groundwave

(r) The following table of logarithmic expressions is to be used as required for determining the minimum permissible ratio of the field strength of a desired to an undesired signal. This table shall be used in conjunction with the protected contours specified in paragraph (q) of this section.

Frequency separation of desired to undesired signals (kHz)Desired Groundwave to:Desired 50% Skywave to Undesired 10% Skywave (dB)
Undesired groundwave (dB)Undesired 10% Skywave (dB)
0262626
1066not presc.

(s) Two stations, one with a frequency twice of the other, should not be assigned in the same groundwave service area unless special precautions are taken to avoid interference from the second harmonic of the station operating on the lower frequency. Additionally, in selecting a frequency, consideration should be given to the fact that occasionally the frequency assignment of two stations in the same area may bear such a relation to the intermediate frequency of some broadcast receivers as to cause “image” interference, However, since this can usually be rectified by readjustment of the intermediate frequency of such receivers, the Commission, in general, will not take this kind of interference into consideration when authorizing stations.

(t) The groundwave service of two stations operating with synchronized carriers and broadcasting identical programs will be subject to some distortion in areas where the signals from the two stations are of comparable strength. For the purpose of estimating coverage of such stations, areas in which the signal ratio is between 1:2 and 2:1 will not be considered as receiving satisfactory service.

Note: Two stations are considered to be operated synchronously when the carriers are maintained within 0.2 Hz of each other and they transmit identical program s.

[56 FR 64862, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992, as amended at 58 FR 27950, May 12, 1993]

§73.183   Groundwave signals.

(a) Interference that may be caused by a proposed assignment or an existing assignment during daytime hours should be determined, when possible, by measurements on the frequency involved or on another frequency over the same terrain and by means for the curves in §73.184 entitled “Ground Wave Field Strength versus Distance.”

Note: Groundwave field strength measurements will not be accepted or considered for the purpose of establishing that interference to a station in a foreign country other than Canada, or that the field strength at the border thereof, would be less than indicated by the use of the ground conductivity maps and engineering standards contained in this part and applicable international agreements. Satisfactory groundwave measurements offered for the purpose of demonstrating values of conductivity other than those shown by Figure M3 in problems involving protection of Canadian stations will be considered only if, after review thereof, the appropriate agency of the Canadian government notifies the Commission that they are acceptable for such purpose.

(b)(1) In all cases where measurements taken in accordance with the requirements are not available, the groundwave strength must be determined by means of the pertinent map of ground conductivity and the groundwave curves of field strength versus distance. The conductivity of a given terrain may be determined by measurements of any broadcast signal traversing the terrain involved. Figure M3 (See Note 1) shows the conductivity throughout the United States by general areas of reasonably uniform conductivity. When it is clear that only one conductivity value is involved, Figure R3 of §73.190, may be used. It is a replica of Figure M3, and is contained in these standards. In all other situations Figure M3 must be employed. It is recognized that in areas of limited size or over a particular path, the conductivity may vary widely from the values given; therefore, these maps are to be used only when accurate and acceptable measurements have not been made.

(2) For determinations of interference and service requiring a knowledge of ground conductivities in other countries, the ground conductivity maps comprising Appendix 1 to Annex 2 of each of the following international agreements may be used:

(i) For Canada, the U.S.-Canada AM Agreement, 1984;

(ii) For Mexico, the U.S.-Mexico AM Agreement, 1986; and

(iii) For other Western Hemisphere countries, the Regional Agreement for the Medium Frequency Broadcasting Service in Region 2.

Where different conductivities appear in the maps of two countries on opposite sides of the border, such differences are to be considered as real, even if they are not explained by geophysical cleavages.

(c) Example of determining interference by the graphs in §73.184:

It is desired to determine whether objectionable interference exists between a proposed 5 kW Class B station on 990 kHz and an existing 1 kW Class B station on first adjacent channel, 1000 kHz. The distance between the two stations is 260 kilometers and both stations operate nondirectionally with antenna systems that produce a horizontal effective field of 282 in mV/m at one kilometer. (See §73.185 regarding use of directional antennas.) The ground conductivity at the site of each station and along the intervening terrain is 6 mS/m. The protection to Class B stations during daytime is to the 500 µV/m (0.5 Vm) contour using a 6 dB protection factor. The distance to the 500 µV/m groundwave contour of the 1 kW station is determined by the use of the appropriate curve in §73.184. Since the curve is plotted for 100 mV/m at a 1 kilometer, to find the distance of the 0.5 mV/m contour of the 1 kw station, it is necessary to determine the distance to the 0.1773 m/Vm contour.

(100 × 0.5 / 282 = 0.1773)

Using the 6 mS/m curve, the estimated radius of the 0.5 mV/m contour is 62.5 kilometers. Subtracting this distance from the distance between the two stations leaves 197.5 kilometers. Using the same propagation curve, the signal from the 5 kW station at this distance is seen to be 0.059 mV/m. Since a protection ratio of 6 dB, desired to undesired signal, applies to stations separated by 10 kHz, the undesired signal could have had a value of up to 0.25 mV/m without causing objectionable interference. For co-channel studies, a desired to undesired signal ratio of no less than 20:1 (26 dB) is required to avoid causing objectionable interference.

(d) Where a signal traverses a path over which different conductivities exist, the distance to a particular groundwave field strength contour shall be determined by the use of the equivalent distance method. Reasonably accurate results may be expected in determining field strengths at a distance from the antenna by application of the equivalent distance method when the unattenuated field of the antenna, the various ground conductivities and the location of discontinuities are known. This method considers a wave to be propagated across a given conductivity according to the curve for a homogeneous earth of that conductivity. When the wave crosses from a region of one conductivity into a region of a second conductivity, the equivalent distance of the receiving point from the transmitter changes abruptly but the field strength does not. From a point just inside the second region the transmitter appears to be at that distance where, on the curve for a homogeneous earth of the second conductivity, the field strength equals the value that occurred just across the boundary in the first region. Thus the equivalent distance from the receiving point to the transmitter may be either greater or less than the actual distance. An imaginary transmitter is considered to exist at that equivalent distance. This technique is not intended to be used as a means of evaluating unattenuated field or ground conductivity by the analysis of measured data. The method to be employed for such determinations is set out in §73.186.

(e) Example of the use of the equivalent distance method;

It is desired to determine the distance to the 0.5 mV/m and 0.025 mV/m contours of a station on a frequency of 1000 kHz with an inverse distance field of 100 mV/m at one kilometer being radiated over a path having a conductivity of 10 mS/m for a distance of 20 kilometers, 5 mS/m for the next 30 kilometers and 15 mS/m thereafter. Using the appropriate curve in §73.184, Graph 12, at a distance of 20 kilometers on the curve for 10 mS/m, the field strength is found to be 2.84 mV/m. On the 5mS/m curve, the equivalent distance to this field strength is 14.92 kilometers, which is 5.08 (20−14.92 kilometers nearer to the transmitter. Continuing on the propagation curve, the distance to a field strength of 0.5 mV/m is found to be 36.11 kilometers.

The actual length of the path travelled, however, is 41.19 (36.11+5.08) kilometers. Continuing on this propagation curve to the conductivity change at 44.92 (50.00−5.08) kilometers, the field strength is found to be 0.304 mV/m. On the 15 mS/m propagation curve, the equivalent distance to this field strength is 82.94 kilometers, which changes the effective path length by 38.02 (82.94−44.92) kilometers. Continuing on this propagation curve, the distance to a field strength of 0.025 mV/m is seen to be 224.4 kilometers. The actual length of the path travelled, however, is 191.46 (224.4+5.08−38.02) kilometers.

[28 FR 13574, Dec. 14, 1963, as amended at 44 FR 36037, June 20, 1979; 48 FR 9011, Mar. 3, 1983; 50 FR 18822, May 2, 1985; 50 FR 24522, June 11, 1985; 51 FR 9965, Mar. 24, 1986; 54 FR 39736, Sept. 28, 1989; 56 FR 64866, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

§73.184   Groundwave field strength graphs.

(a) Graphs 1 to 20 show, for each of 20 frequencies, the computed values of groundwave field strength as a function of groundwave conductivity and distance from the source of radiation. The groundwave field strength is considered to be that part of the vertical component of the electric field which has not been reflected from the ionosphere nor from the troposphere. These 20 families of curves are plotted on log-log graph paper and each is to be used for the range of frequencies shown thereon. Computations are based on a dielectric constant of the ground (referred to air as unity) equal to 15 for land and 80 for sea water and for the ground conductivities (expressed in mS/m) given on the curves. The curves show the variation of the groundwave field strength with distance to be expected for transmission from a vertical antenna at the surface of a uniformly conducting spherical earth with the groundwave constants shown on the curves. The curves are for an antenna power of such efficiency and current distribution that the inverse distance (unattenuated) field is 100 mV/m at 1 kilometer. The curves are valid for distances that are large compared to the dimensions of the antenna for other than short vertical antennas.

(b) The inverse distance field (100 mV/m divided by the distance in kilometers) corresponds to the groundwave field intensity to be expected from an antenna with the same radiation efficiency when it is located over a perfectly conducting earth. To determine the value of the groundwave field intensity corresponding to a value of inverse distance field other than 100 mV/m at 1 kilometer, multiply the field strength as given on these graphs by the desired value of inverse distance field at 1 kilometer divided by 100; for example, to determine the groundwave field strength for a station with an inverse distance field of 2700 mV/m at 1 kilometer, simply multiply the values given on the charts by 27. The value of the inverse distance field to be used for a particular antenna depends upon the power input to the antenna, the nature of the ground in the neighborhood of the antenna, and the geometry of the antenna. For methods of calculating the interrelations between these variables and the inverse distance field, see “The Propagation of Radio Waves Over the Surface of the Earth and in the Upper Atmosphere,” Part II, by Mr. K.A. Norton, Proc. I.R.E., Vol. 25, September 1937, pp. 1203-1237.

Note: The computed values of field strength versus distance used to plot Graphs 1 to 20 are available in tabular form. For information on obtaining copies of these tabulations call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 20554, (202) 632-7000.

(c) Provided the value of the dielectric constant is near 15, the ground conductivity curves of Graphs 1 to 20 may be compared with actual field strength measurement data to determine the appropriate values of the ground conductivity and the inverse distance field strength at 1 kilometer. This is accomplished by plotting the measured field strengths on transparent log-log graph paper similar to that used for Graphs 1 to 20 and superimposing the plotted graph over the Graph corresponding to the frequency of the station measured. The plotted graph is then shifted vertically until the plotted measurement data is best aligned with one of the conductivity curves on the Graph; the intersection of the inverse distance line on the Graph with the 1 kilometer abscissa on the plotted graph determines the inverse distance field strength at 1 kilometer. For other values of dielectric constant, the following procedure may be used to determine the dielectric constant of the ground, the ground conductivity and the inverse distance field strength at 1 kilometer. Graph 21 gives the relative values of groundwave field strength over a plane earth as a function of the numerical distance p and phase angle b. On graph paper with coordinates similar to those of Graph 21, plot the measured values of field strength as ordinates versus the corresponding distances from the antenna in kilometers as abscissae. The data should be plotted only for distances greater than one wavelength (or, when this is greater, five times the vertical height of the antenna in the case of a nondirectional antenna or 10 times the spacing between the elements of a directional antenna) and for distances less than 80f1/3 MHz kilometers (i.e., 80 kilometers at 1 MHz). Then, using a light box, place the plotted graph over Graph 21 and shift the plotted graph vertically and horizontally (making sure that the vertical lines on both sheets are parallel) until the best fit with the data is obtained with one of the curves on Graph 21. When the two sheets are properly lined up, the value of the field strength corresponding to the intersection of the inverse distance line of Graph 21 with the 1 kilometer abscissa on the data sheet is the inverse distance field strength at 1 kilometer, and the values of the numerical distance at 1 kilometer, p1, and of b are also determined. Knowing the values of b and p1 (the numerical distance at one kilometer), we may substitute in the following approximate values of the ground conductivity and dielectric constant.

eCFR graphic ec13no91.018.gif

View or download PDF

(R/λ)1 = Number of wavelengths in 1 kilometer,

*   *   *   *   *

fMHz=frequency expressed in megahertz,

eCFR graphic ec13no91.019.gif

View or download PDF

ε = dielectric constant on the ground referred to air as unity.

First solve for χ by substituting the known values of p1, (R/λ)1, and cos b in equation (1). Equation (2) may then be solved for δ and equation (3) for ε. At distances greater than 80/f1/3 MHz kilometers the curves of Graph 21 do not give the correct relative values of field strength since the curvature of the earth weakens the field more rapidly than these plane earth curves would indicate. Thus, no attempt should be made to fit experimental data to these curves at the larger distances.

Note: For other values of dielectric constant, use can be made of the computer program which was employed by the FCC in generating the curves in Graphs 1 to 20. For information on obtaining a printout of this program, call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 200554, (202) 632-7000.

(d) At sufficiently short distances (less than 55 kilometers at AM broadcast frequencies), such that the curvature of the earth does not introduce an additional attenuation of the waves, the curves of Graph 21 may be used to determine the groundwave field strength of transmitting and receiving antennas at the surface of the earth for any radiated power, frequency, or set of ground constants. First, trace the straight inverse distance line corresponding to the power radiated on transparent log-log graph paper similar to that of Graph 21, labelling the ordinates of the chart in terms of field strength, and the abscissae in terms of distance. Next, using the formulas given on Graph 21, calculate the value of the numerical distance, p, at 1 kilometer, and the value of b. Then superimpose the log-log graph paper over Graph 21, shifting it vertically until both inverse distance lines coincide and shifting it horizontally until the numerical distance at 1 kilometer on Graph 21 coincides with 1 kilometer on the log-log graph paper. The curve of Graph 21 corresponding to the calculated value of b is then traced on the log-log graph paper giving the field strength versus distance in kilometers.

(e) This paragraph consists of the following Graphs 1 to 20 and 21.

Note: The referenced graphs are not published in the CFR, nor will they be included in the Commission's automated rules system. For information on obtaining copies of the graphs call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 20554, Telephone: (202) 632-7000.

[28 FR 13574, Dec. 14, 1963, as amended at 50 FR 18823, May 2, 1985; 51 FR 45891, Dec. 23, 1986; 52 FR 36878, Oct. 1, 1987; 56 FR 64866, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

§73.185   Computation of interfering signal.

(a) Measured values of radiation are not to be used in calculating overlap, interference, and coverage.

(1) In the case of an antenna which is intended to be non-directional in the horizontal plane, an ideal non-directional radiation pattern shall be used in determining interference, overlap, and coverage, even if the antenna is not actually non-directional.

(2) In the case of an antenna which is directional in the horizontal plane, the radiation which shall be used in determining interference, overlap, and coverage is that calculated pursuant to §73.150 or §73.152, depending on whether the station has a standard or modified standard pattern.

(3) In the case of calculation of interference or overlap to (not from) a foreign station, the notified radiation shall be used, even if the notified radiation differs from that in paragraphs (a) (1) or (2) of this section.

(b) For skywave signals from stations operating on all channels, interference shall be determined from the appropriate formulas and Figure 6a contained in §73.190.

(c) The formulas in §73.190(d) depicted in Figure 6a of §73.190, entitled “Angles of Departure versus Transmission Range” are to be used in determining the angles in the vertical pattern of the antenna of an interfering station to be considered as pertinent to transmission by one reflection. To provide for variation in the pertinent vertical angle due to variations of ionosphere height and ionosphere scattering, the curves 2 and 3 indicate the upper and lower angles within which the radiated field is to be considered. The maximum value of field strength occurring between these angles shall be used to determine the multiplying factor to apply to the 10 percent skywave field intensity value determined from Formula 2 in §73.190. The multiplying factor is found by dividing the maximum radiation between the pertinent angles by 100 mV/m.

(d) Example of the use of skywave curves and formulas: Assume a proposed new Class B station from which interference may be expected is located at a distance of 724 kilometers from a licensed Class B station. The proposed station specifies geographic coordinates of 40°0000 N and 100°0000 W and the station to be protected is located at an azimuth of 45° true at geographic coordinates of 44°2605 N and 93°3254 W. The critical angles of radiation as determined from Figure 6a of §73.190 for use with Class B stations are 9.6° and 16.6°. If the vertical pattern of the antenna of the proposed station in the direction of the existing station is such that, between the angles of 9.6° and 16.6° above the horizon the maximum radiation is 260 mV/m at one kilometer, the value of the 50% field, as derived from Formula 1 of §73.190, is 0.06217 mV/m at the location of the existing station. To obtain the value of the 10% field, the 50% value must be adjusted by a factor derived from Formula 2 of §73.190. The value in this case is 8.42 dB. Thus, the 10% field is 0.1616 mV/m. Using this in conjunction with the co-channel protection ratio of 26 dB, the resultant nighttime limit from the proposed station to the licensed station is 3.232 mV/m.

(e) In the case of an antenna which is non-directional in the horizontal plane, the vertical distribution of the relative fields should be computed pursuant to §73.160. In the case of an antenna which is directional in the horizontal plane, the vertical pattern in the great circle direction toward the point of reception in question must first be calculated. In cases where the radiation in the vertical plane, at the pertinent azimuth, contains a large lobe at a higher angle than the pertinent angle for one reflection, the method of calculating interference will not be restricted to that just described; each such case will be considered on the basis of the best knowledge available.

(f) In performing calculations to determine permissible radiation from stations operating presunrise or postsunset in accordance with §73.99, calculated diurnal factors will be multiplied by the values of skywave field strength for such stations obtained from Formula 1 or 2 of §73.190.

(1) The diurnal factor is determined using the time of day at the mid-point of path between the site of the interfering station and the point at which interference is being calculated. Diurnal factors are computed using the formula Df=a+bF+cF2+dF3 where:

Df represents the diurnal factor,

F is the frequency in MHz,

a,b,c, and d are constants obtained from the tables in paragraph (k)(2)

A diurnal factor greater than one will not be used in calculations and interpolation is to be used between calculated values where necessary. For reference purposes, curves for presunrise and postsunset diurnal factors are contained in Figures 13 and 14 of §73.190.

(2) Constants used in calculating diurnal factors for the presunrise and postsunset periods are contained in paragraphs (f)(2) (i) and (ii) of this section respectively. The columns labeled Tmp represent the number of hours before and after sunrise and sunset at the path midpoint.

(i) Presunrise Constants

Tmpabcd
−21.3084.0083−.0155.0144
−1.751.3165−.4919.6011−.1884
−1.51.0079.0296.1488−.0452
−1.25.7773.3751−.1911.0736
−1.6230.1547.2654−.1006
−.75.3718.1178.3632−.1172
−.5.2151.0737.4167−.1413
−.25.2027−.2560.7269−.2577
SR.1504−.2325.5374−.1729
+.25.1057−.2092.4148−.1239
+5..0642−.1295.2583−.0699
+.75.0446−.1002.1754−.0405
+1.0148.0135.0462.0010

(ii) Postsunset Constants

Tmpabcd
1.75.9495−.0187.0720−.0290
1.5.7196.3583−.2280.0611
1.25.6756.1518.0279−.0163
1.0.5486.1401.0952−.0288
.75.3003.4050−.0961.0256
.5.1186.4281−.0799.0197
.25.0382.3706−.0673.0171
SS.0002.3024−.0540.0086
−.25.0278.0458.1473−.0486
−.5.0203.0132.1166−.0340
−.75.0152−.0002.0786−.0185
−1.0−.0043.0452−.0040.0103
−1.25.0010.0135.0103.0047
−1.5.0018.0052.0069.0042
−1.75−.0012.0122−.0076.0076
−2.0−.0024.0141−.0141.0091

Editorial Note: At 56 FR 64867, Dec. 12, 1991, §73.185 was amended by redesignating paragraphs (d), (e), (h), and (k) as (c), (d), (e), and (f), resulting in two consecutive paragraph (f)'s. These paragraphs will be correctly designated by a Federal Communication Commission document published in the Federal Register at a later date.

(f) For stations operating on regional and local channels, interfering skywave field intensities shall be determined in accordance with the procedure specified in (d) of this section and illustrated in (e) of this section, except that Figure 2 of §73.190 is used in place of Figure 1a and 1b and the formulas of §73.190. In using Figure 2 of §73.190, one additional parameter must be considered, i.e., the variation of received field with the latitude of the path.

(g) Figure 2 of §73.190, “10 percent Skywave Signal Range Chart,” shows the signal as a function of the latitude of the transmission path, which is defined as the geographic latitude of the midpoint between the transmitter and receiver. When using Figure 2 of §73.190, latitude 35° should be used in case the mid-point of the path lies below 35° North and latitude 50° should be used in case the mid-point of the path lies above 50° North.

[30 FR 13783, Oct. 29, 1965, as amended at 33 FR 15420, Oct. 17, 1968; 46 FR 11995, Feb. 12, 1981; 48 FR 42958, Sept. 20, 1983; 50 FR 18843, May 2, 1985; 56 FR 64867, Dec. 12, 1991]

§73.186   Establishment of effective field at one kilometer.

(a) Section 73.189 provides that certain minimum field strengths are acceptable in lieu of the required minimum physical heights of the antennas proper. Also, in other situations, it may be necessary to determine the effective field. The following requirements shall govern the taking and submission of data on the field strength produced:

(1) Beginning as near to the antenna as possible without including the induction field and to provide for the fact that a broadcast antenna is not a point source of radiation (not less than one wave length or 5 times the vertical height in the case of a single element, i.e., nondirectional antenna or 10 times the spacing between the elements of a directional antenna), measurements shall be made on six or more radials, at intervals of approximately 0.2 kilometer up to 3 kilometers from the antenna, at intervals of approximately one kilometer from 3 kilometers to 5 kilometers from the antenna, at intervals of approximately 2 kilometers from 5 kilometers to 15 kilometers from the antenna, and a few additional measurements if needed at greater distances from the antenna. Where the antenna is rurally located and unobstructed measurements can be made, there shall be at least 15 measurements on each radial. These shall include at least 7 measurements within 3 kilometers of the antenna. However, where the antenna is located in a city where unobstructed measurements are difficult to make, measurements shall be made on each radial at as many unobstructed locations as possible, even though the intervals are considerably less than stated above, particularly within 3 kilometers of the antenna. In cases where it is not possible to obtain accurate measurements at the closer distances (even out to 8 or 10 kilometers due to the character of the intervening terrain), the measurements at greater distances should be made at closer intervals.

(2) The data required by paragraph (a)(1) of this section should be plotted for each radial in accordance with either of the two methods set forth below:

(i) Using log-log coordinate paper, plot field strengths as ordinate and distance as abscissa.

(ii) Using semi-log coordinate paper, plot field strength times distance as ordinate on the log scale and distance as abscissa on the linear scale.

(3) However, regardless of which of the methods in paragraph (a)(2) of this section is employed, the proper curve to be drawn through the points plotted shall be determined by comparison with the curves in §73.184 as follows: Place the sheet on which the actual points have been plotted over the appropriate Graph in §73.184, hold to the light if necessary and adjust until the curve most closely matching the points is found. This curve should then be drawn on the sheet on which the points were plotted, together with the inverse distance curve corresponding to that curve. The field at 1 kilometer for the radial concerned shall be the ordinate on the inverse distance curve at 1 kilometer.

(4) When all radials have been analyzed in accordance with paragraph (a)(3) of this section, a curve shall be plotted on polar coordinate paper from the fields obtained, which gives the inverse distance field pattern at 1 kilometer. The radius of a circle, the area of which is equal to the area bounded by this pattern, is the effective field. (See §73.14.)

(5) The antenna power of the station shall be maintained at the authorized level during all field measurements. The power determination will be made using the direct method as described in §73.51(a) with instruments of acceptable accuracy specified in §73.1215.

(b) Complete data taken in conjunction with the field strength measurements shall be submitted to the Commission in affidavit form including the following:

(1) Tabulation by number of each point of measurement to agree with the maps required in paragraph (c) of this section, the date and time of each measurement, the field strength (E), the distance from the antenna (D) and the product of the field strength and distance (ED) (if data for each radial are plotted on semilogarithmic paper, see paragraph (a)(2)(ii) of this section) for each point of measurement.

(2) Description of method used to take field strength measurements.

(3) The family of theoretical curves used in determining the curve for each radial properly identified by conductivity and dielectric constants.

(4) The curves drawn for each radial and the field strength pattern.

(5) The antenna resistance at the operating frequency.

(6) Antenna current or currents maintained during field strength measurements.

(c) Maps showing each measurement point numbered to agree with the required tabulation shall be retained in the station records and shall be available to the FCC upon request.

[28 FR 13574, Dec. 14, 1963, as amended at 41 FR 44178, Oct. 7, 1976; 46 FR 11995, Feb. 12, 1981; 49 FR 49851, Dec. 24, 1984; 50 FR 18843, May 2, 1985; 50 FR 47055, Nov. 14, 1985; 51 FR 2707, Jan. 21, 1986; 52 FR 10570, Apr. 2, 1987; 66 FR 20757, Apr. 25, 2001]

§73.187   Limitation on daytime radiation.

(a)(1) Except as otherwise provided in paragraphs (a)(2) and (3) of this section, no authorization will be granted for a Class B or Class D station on a frequency specified in §73.25 if the proposed operation would radiate during the period of critical hours (the two hours after local sunrise and the two hours before local sunset) toward any point on the 0.1 mV/m contour of a co-channel U.S. Class A station, at or below the pertinent vertical angle determined from Curve 2 of Figure 6a of §73.190, values in excess of those obtained as provided in paragraph (b) of this section.

(2) The limitation set forth in paragraph (a)(1) of this section shall not apply in the following cases:

(i) Any Class B or Class D operation authorized before November 30, 1959; or

(ii) For Class B and Class D stations authorized before November 30, 1959, subsequent changes of facilities which do not involve a change in frequency, an increase in radiation toward any point on the 0.1 mV/m contour of a co-channel U.S. Class A station, or the move of transmitter site materially closer to the 0.1 mV/m contour of such Class A station.

(3) A Class B or Class D station authorized before November 30, 1959, and subsequently authorized to increase daytime radiation in any direction toward the 0.1 mV/m contour of a co-channel U.S. Class A station (without a change in frequency or a move of transmitter site materially closer to such contour), may not, during the two hours after local sunrise or the two hours before local sunset, radiate in such directions a value exceeding the higher of:

(i) The value radiated in such directions with facilities last authorized before November 30, 1959, or

(ii) The limitation specified in paragraph (a)(1) of this section.

(b) To obtain the maximum permissible radiation for a Class B or Class D station on a given frequency from 640 through 990 kHz, multiply the radiation value obtained for the given distance and azimuth from the 500 kHz chart (Figure 9 of §73.190) by the appropriate interpolation factor shown in the K500 column of paragraph (c) of this section; and multiply the radiation value obtained for the given distance and azimuth from the 1000 kHz chart (Figure 10 of §73.190) by the appropriate interpolation factor shown in the K1000 column of paragraph (c) of this section. Add the two products thus obtained; the result is the maximum radiation value applicable to the Class B or Class D station in the pertinent directions. For frequencies from 1010 to 1580 kHz, obtain in a similar manner the proper radiation values from the 1000 and 1600 kHz charts (Figures 10 and 11 of §73.190), multiply each of these values by the appropriate interpolation factors in the K′1000 and K′1600 columns in paragraph (c) of this section, and add the products.

(c) Interpolation factors. (1) Frequencies below 1000 kHz.

fkHzK500K1000
6400.7200.280
6500.7000.300
6600.6800.320
6700.6600.340
6800.6400.360
6900.6200.380
7000.6000.400
7100.5800.420
7200.5600.440
7300.5400.460
7400.5200.480
7500.5000.500
7600.4800.520
7700.4600.540
7800.4400.560
8000.4000.600
8100.3800.620
8200.3600.640
8300.3400.660
8400.3200.680
8500.3000.700
8600.2800.720
8700.2600.740
8800.2400.760
8900.2200.780
9000.2000.800
9400.1200.880
9900.0200.980

(2) Frequencies above 1000 kHz.

f′kHzK′1000K′1600
10100.9830.017
10200.9670.033
10300.9500.050
10400.9330.067
10500.9170.083
10600.9000.100
10700.8830.117
10800.8670.133
10900.8500.150
11000.8330.167
11100.8170.183
11200.8000.200
11300.7830.217
11400.7670.233
11600.7330.267
11700.7170.283
11800.7000.300
11900.6830.317
12000.6670.333
12100.6500.350
12200.6330.367
15000.1670.833
15100.1500.850
15200.1330.867
15300.1170.883
15400.1000.900
15500.0830.917
15600.0670.933
15700.0500.950
15800.0330.967

[28 FR 13574, Dec. 14, 1963, as amended at 49 FR 43962, Nov. 1, 1984; 56 FR 64868, Dec. 12, 1991]

§73.189   Minimum antenna heights or field strength requirements.

(a) Section 73.45 requires that all applicants for new, additional, or different broadcast facilities and all licensees requesting authority to move 0the transmitter of an existing station, shall specify a radiating system, the efficiency of which complies with the requirements of good engineering practice for the class and power of the station.

(b) The specifications deemed necessary to meet the requirements of good engineering practice at the present state of the art are set out in detail below.

(1) The licensee of a AM broadcast station requesting a change in power, time of operation, frequency, or transmitter location must also request authority to install a new antenna system or to make changes in the existing antenna system which will meet the minimum height requirements, or submit evidence that the present antenna system meets the minimum requirements with respect to field strength, before favorable consideration will be given thereto. (See §73.186.) In the event it is proposed to make substantial changes in an existing antenna system, the changes shall be such as to meet the minimum height requirements or will be permitted subject to the submission of field strength measurements showing that it meets the minimum requirements with respect to effective field strength.

(2) These minimum actual physical vertical heights of antennas permitted to be installed are shown by curves A, B, and C of Figure 7 of §73.190 as follows:

(i) Class C stations, and stations in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands on 1230, 1240, 1340, 1400, 1450 and 1490 kHz that were formerly Class C and were redesignated as Class B pursuant to §73.26(b), 45 meters or a minimum effective field strength of 241 mV/m for 1 kW (121 mV/m for 0.25 kW). (This height applies to a Class C station on a local channel only. Curve A shall apply to any Class C stations in the 48 conterminous States that are assigned to Regional channels.)

(ii) Class A (Alaska), Class B and Class D stations other than those covered in §73.189(b)(2)(i), a minimum effective field strength of 282 mV/m for 1 kW.

(iii) Class A stations, a minimum effective field strength of 362 mV/m for 1 kW.

(3) The heights given on the graph for the antenna apply regardless of whether the antenna is located on the ground or on a building. Except for the reduction of shadows, locating the antenna on a building does not necessarily increase the efficiency and where the height of the building is in the order of a quarter wave the efficiency may be materially reduced.

(4) At the present development of the art, it is considered that where a vertical radiator is employed with its base on the ground, the ground system should consist of buried radial wires at least one-fourth wave length long. There should be as many of these radials evenly spaced as practicable and in no event less than 90. (120 radials of 0.35 to 0.4 of a wave length in length and spaced 3° is considered an excellent ground system and in case of high base voltage, a base screen of suitable dimensions should be employed.)

(5) In case it is contended that the required antenna efficiency can be obtained with an antenna of height or ground system less than the minimum specified, a complete field strength survey must be supplied to the Commission showing that the field strength at a mile without absorption fulfills the minimum requirements. (See §73.186.) This field survey must be made by a qualified engineer using equipment of acceptable accuracy.

(6) The main element or elements of a directional antenna system shall meet the above minimum requirements with respect to height or effective field strength. No directional antenna system will be approved which is so designed that the effective field of the array is less than the minimum prescribed for the class of station concerned, or in case of a Class A station less than 90 percent of the ground wave field which would be obtained from a perfect antenna of the height specified by Figure 7 of §73.190 for operation on frequencies below 1000 kHz, and in the case of a Class B or Class D station less than 90 percent of the ground wave field which would be obtained from a perfect antenna of the height specified by Figure 7 of §73.190 for operation on frequencies below 750 kHz.

[28 FR 13574, Dec. 14, 1963, as amended at 31 FR 8069, June 8, 1966; 33 FR 15420, Oct. 17, 1968; 44 FR 36038, June 20, 1979; 50 FR 18844, May 2, 1985; 51 FR 2707, Jan. 21, 1986; 51 FR 4753, Feb. 7, 1986; 52 FR 10570, Apr. 2, 1987; 56 FR 64868, Dec. 12, 1991]

§73.190   Engineering charts and related formulas.

(a) This section consists of the following Figures: 2, r3, 5, 6a, 7, 8, 9, 10, 11, 12, and 13. Additionally, formulas that are directly related to graphs are included.

(b) Formula 1 is used for calculation of 50% skywave field strength values.

Formula 1. Skywave field strength, 50% of the time (at SS+6):

The skywave field strength, Fc(50), for a characteristic field strength of 100 mV/m at 1 km is given by:

eCFR graphic ec01mr91.068.gif

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The slant distance, D, is given by:

eCFR graphic ec13no91.020.gif

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The geomagnetic latitude of the midpoint of the path, ΦM, is given by:

ΦM =arcsin[sin aM sin 78.5° + cos aM cos 78.5° cos(69 + bM)]degrees                        (Eq. 3)

The short great-circle path distance, d, is given by:

eCFR graphic ec13no91.021.gif

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Where:

d° = arccos[sin aT sin aR + cos aT cos aR cos(bRbT)]degrees                              (Eq.5)

Where:

aT is the geographic latitude of the transmitting terminal (degrees)

aR is the geographic latitude of the receiving terminal (degrees)

bT is the geographic longitude of the transmitting terminal (degrees)

bR is the geographic longitude of the receiving terminal (degrees)

aM is the geographic latitude of the midpoint of the great-circle path (degrees) and is given by:

bM is the geographic longitude of the midpoint of the great-circle path (degrees) and is given by:

eCFR graphic ec01mr91.069.gif

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eCFR graphic ec01mr91.070.gif

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Note (1): If |FM| is greater than 60 degrees, equation (1) is evaluated for | FM| = 60 degrees.

Note (2): North and east are considered positive; south and west negative.

Note (3): In equation (7), k = −1 for west to east paths (i.e., bR >bT), otherwise k = 1.

(c) Formula 2 is used for calculation of 10% skywave field strength values.

Formula 2. Skywave field strength, 10% of the time (at SS+6):

The skywave field strength, Fc(10), is given by:

Fc(10) = Fc(50) + Δ      dB(µV/m)

Where:

Δ = 6 when | FM| <40

Δ = 0.2 | FM| − 2 when 40 ≤| FM| ≤60

Δ = 10 when | FM| >60

(d) Figure 6a depicts angles of departure versus transmission range. These angles may also be computed using the following formulas:

eCFR graphic ec01mr91.071.gif

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Where:

d=distance in kilometers

n=1 for 50% field strength values

n=2 or 3 for 10% field strength values

and where

K1=0.00752

K2=0.00938

K3=0.00565

Note: Computations using these formulas should not be carried beyond 0.1 degree.

(e) In the event of disagreement between computed values using the formulas shown above and values obtained directly from the figures, the computed values will control.

eCFR graphic ec01mr91.072.gif

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eCFR graphic ec01mr91.073.gif

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eCFR graphic ec01mr91.074.gif

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eCFR graphic ec01mr91.075.gif

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eCFR graphic ec01mr91.076.gif

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eCFR graphic ec01mr91.077.gif

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eCFR graphic ec01mr91.078.gif

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eCFR graphic ec01mr91.079.gif

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eCFR graphic ec01mr91.080.gif

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eCFR graphic ec01mr91.081.gif

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eCFR graphic ec01mr91.082.gif

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eCFR graphic ec01mr91.083.gif

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eCFR graphic ec01mr91.084.gif

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[28 FR 13574, Dec. 14, 1963, as amended at 30 FR 12720, Oct. 6, 1965; 33 FR 15420, Oct. 17, 1968; 48 FR 42959, Sept. 20, 1983; 49 FR 43963, Nov. 1, 1984; 50 FR 18844, May 2, 1985; 51 FR 4753, Feb. 7, 1986; 52 FR 36879, Oct. 1, 1987; 56 FR 64869, Dec. 12, 1991]

Subpart B—FM Broadcast Stations

§73.201   Numerical designation of FM broadcast channels.

The FM broadcast band consists of that portion of the radio frequency spectrum between 88 MHz and 108 MHz. It is divided into 100 channels of 200 kHz each. For convenience, the frequencies available for FM broadcasting (including those assigned to noncommercial educational broadcasting) are given numerical designations which are shown in the table below:

Frequency (Mc/s)Channel No.
88.1201
88.3202
88.5203
88.7204
88.9205
89.1206
89.3207
89.5208
89.7209
89.9210
90.1211
90.3212
90.5213
90.7214
90.9215
91.1216
91.3217
91.5218
91.7219
91.9220
92.1221
92.3222
92.5223
92.7224
92.9225
93.1226
93.3227
93.5228
93.7229
93.9230
94.1231
94.3232
94.5233
94.7234
94.9235
95.1236
95.3237
95.5238
95.7239
95.9240
96.1241
96.3242
96.5243
96.7244
96.9245
97.1246
97.3247
97.5248
97.7249
97.9250
98.1251
98.3252
98.5253
98.7254
98.9255
99.1256
99.3257
99.5258
99.7259
99.9260
100.1261
100.3262
100.5263
100.7264
100.9265
101.1266
101.3267
101.5268
101.7269
101.9270
102.1271
102.3272
102.5273
102.7274
102.9275
103.1276
103.3277
103.5278
103.7279
103.9280
104.1281
104.3282
104.5283
104.7284
104.9285
105.1286
105.3287
105.5288
105.7289
105.9290
106.1291
106.3292
106.5293
106.7294
106.9295
107.1296
107.3297
107.5298
107.7299
107.9300

Note: The frequency 108.0 MHz may be assigned to VOR test stations subject to the condition that interference is not caused to the reception of FM broadcasting stations, present or future.

[28 FR 13623, Dec. 14, 1963, as amended at 30 FR 4480, Apr. 7, 1965; 52 FR 10570, Apr. 2, 1987]

§73.202   Table of Allotments.

Link to an amendment published at 78 FR 25591, May 2, 2013.

Link to an amendment published at 79 FR 59448, October 2, 2014.

Link to an amendment published at 79 FR 61787, October 15, 2014.

Link to an amendment published at 79 FR 62883, October 21, 2014.

(a) General. The following Table of Allotments contains the channels (other than noncommercial educational Channels 201-220) designated for use in communities in the United States, its territories, and possessions, and not currently assigned to a licensee or permittee or subject to a pending application for construction permit or license. All listed channels are for Class B stations in Zones I and I-A and for Class C stations in Zone II unless otherwise specifically designated. Channels to which licensed, permitted, and “reserved” facilities have been assigned are reflected in the Media Bureau's publicly available Consolidated Data Base System.

(1) Channels designated with an asterisk may be used only by noncommercial educational broadcast stations. The rules governing the use of those channels are contained in part 73, subpart C of this chapter. An entity that would be eligible to operate a noncommercial educational broadcast station can, in conjunction with an initial petition for rulemaking filed pursuant to part 1, subpart C of this chapter, request that a nonreserved FM channel (channels 221 through 300) be allotted as reserved only for noncommercial educational broadcasting by demonstrating the following:

(i) No reserved channel can be used without causing prohibited interference to TV channel 6 stations or foreign broadcast stations; or

(ii) The applicant is technically precluded from using the reserved band by existing stations or previously filed applications and the proposed station would provide a first or second noncommercial educational radio service to 2,000 or more people who constitute 10% of the population within the proposed allocation's 60 dBu (1 mV/m) service contour.

(2) Each channel listed in the Table of Allotments reflects the class of station that is authorized to use it based on the minimum and maximum facility requirements for each class contained in §73.211.

Note: The provisions of this paragraph [(a)(2) of this section] become effective [3 years from the effective date of the Report and Order in BC Docket 80-90].

(b) Table of FM Allotments.

  Channel No.
ALABAMA
Anniston*261C3
Frisco City278A
Waverly262A
ALASKA
      
      
ARIZONA
Bagdad269C3
Ehrenberg228C2
First Mesa281C
Fredonia278C1
Leupp293C2
McNary249C1
Overgaard232C3
Paulden228C3
Peach Springs†265A, 281C3
Pima*296A
Pinetop294C1
Quartzsite275C3, 290C2
Sells285A
Snowflake258C2
Somerton*260C3
Wickenburg229C3
Willcox*223C3
ARKANSAS
Bearden224A
Cove232A
Daisy293C3
Dermott224A
Greenwood268A
Heber Springs270C3
Hermitage300A
Lake Village278C3
Rison255A
CALIFORNIA
Alturas268C1, 277C
Amboy284A
Barstow267A
Cambria293A
Cottonwood221A
Essex280B
Greenfield254A
Hemet*273A
Lake Isabella239A
McKinleyville*277C3
Mecca274A
Mojave255A
Murrieta281A
Portola269A
Randsburg275A
San Joaquin299A
Shasta Lake224A
Sutter Creek*298A
Wasco224A
Westley*238A
Willow Creek258A
Wofford Heights251A
COLORADO
Akron279C1
Dove Creek229C3
Durango287A
Lake City247A
Olathe*270C2, *293C
Steamboat Springs255A, 289A
Strasburg249C3
Stratton246C1
CONNECTICUT
DELAWARE
DISTRICT OF COLUMBIA
FLORIDA
Big Pine Key*239A
Cross City249C3
Horseshoe Beach*234C3
Lake Park262A
Live Oak*261A
Otter Creek*240A
Silver Springs Shore259A
GEORGIA
Alamo287C3
Americus295A
Cusseta279A
Homerville246A
Maysville265A
Plains290A
Reynolds*245A
St. Simons Island229C3
Tignall287A
HAWAII
      
Kualapuu296C2
IDAHO
McCall228C3, 238C3, 276C3
Weiser*280C1
ILLINOIS
Abingdon252A
Altamont288A
Canton*277A
Cedarville*258A
Clifton*297A
Cuba252A
Freeport*295A
Grayville229A
Greenup*230A
Pinckneyville*282A
West Salem266A
INDIANA
Bloomfield266A
Columbus*228A
Farmersburg*242A
Fowler*291A
Madison*265A
Terre Haute*298B
IOWA
Asbury*238A
Keosauqua*271C3
Moville*246A
Rudd*268A
KANSAS
Americus240A
Atwood292C0
Council Grove*281C3
KENTUCKY
Irvington261A
Perryville298A
Smith Mills*233A
LOUISIANA
Anacoco276C3
Bastrop228A
Clayton266A
Florien242A
Golden Meadow*289C2
Harrisonburg232A
Haynesville286A
Hornbeck269A
Oil City285A
Ringgold*253C3
Rosepine281A
Wisner300C3
MAINE
MARYLAND
Newark235A
MASSACHUSETTS
      
West Tisbury*282A
MICHIGAN
Custer260A
Harrison280A
Hubbardston*279A
Houghton242C1
Lexington*256A
Ludington242A
Traverse City283A
MINNESOTA
Baudette233C1
Grand Portage224C, 245C0, 274C
MISSISSIPPI
Bruce233A
Cleveland226C2
Drew237A
Mound Bayou270A
Oxford286A
Summit228A
Vardaman258A
MISSOURI
Alton290A
Bunker292C3
Columbia252C2
Eminence281A
Huntsville*278C2
Laurie*265C3
MONTANA
Bozeman*240C3
Cut Bank265C1
Lima265C2
NEBRASKA
      
   
NEVADA
Owyhee247C3
Silver Springs273C
NEW HAMPSHIRE
Enfield282A
Groveton268A
NEW JERSEY
NEW MEXICO
Alamo Community*298A
Animas279C1
Cloudcroft250C1
Roswell237C0
Taos288A
Taos Pueblo292C3
Tohatchi268C2
Virden228C1
NEW YORK
Amherst*221A
Keeseville231A
Rhinebeck*273A
Rosendale255A, 273A
Westfield265A
NORTH CAROLINA
Dillsboro*237A
   
NORTH DAKOTA
Berthold*264C
      
OHIO
      
North Madison229A
OKLAHOMA
Arnett285C2
Buffalo224C2
Clayton262A
Coalgate242A
Cordell*229A
Erick259C2
Haworth294A
Hennessey249A
Holdenville265A
Leedey297A
Millerton265C2
Mooreland254A
Okeene268C3
Reydon264C2
Ringwood285A
Savanna275A
Taloga226A
Thomas288A
Tipton233C3
Vici249A
Waukomis292A
Waynoka231C2
Weatherford*286A
Wright City226A
Wynnewood*283A
OREGON
Altamont249C1
Arlington295C2
Boardman231C3
Dallas*252C3
Gearhart227A
Ione258A
Madras*243C1
Manzanita248C3
Merrill289A
Monument280C1
Powers293C2
Prairie City272C
Prineville267C1
The Dalles*268C3
Waldport229C2
PENNSYLVANIA
Erie240A
Liberty*298A
Susquehanna*227A
RHODE ISLAND
SOUTH CAROLINA
   
      
SOUTH DAKOTA
Edgemont289C1
Lead232C
Rosebud257C
TENNESSEE
      
Englewood250A
TEXAS
Annona263A
Asherton284A
Aspermont226C2
Austwell290A
Balmorhea283C
Bangs250C3
Batesville250A
Big Lake296C2
Big Spring265C3
Bruni293A
Burnet*240A
Canadian235C1
Carbon238A
Carrizo Springs295A
Centerville267A, 274A
Christine245C3
Comanche280A
Cotulla264A
Crosbyton264C3
Crowell255C3
Cuney259A
Dalhart261C
Denver City*248C2
Dickens240A, 294A
Early294A
El Indio236A
Encinal259A, 286A
Encino250A, 283A
Estelline263C3
Fort Stockton263C
Freer288A
Garwood247A
George West292A
Goldwaithe297A
Goree275A
Groom223A
Guthrie252A
Hale Center236C1
Harper256C3
Hawley269A
Hebbronville282A
Hico293A
Idalou299A
Iraan269C2
Jacksonville236A
Jayton231C2
Junction277C3, 284A, 297A
Kermit229A
Knox City293A
Leakey257A, 275A, 299A
Llano242C3
Lockney271C3
Lometa253A
Longview300C2
Lovelady288A
Marathon278C
Markham283A
Mason281C2
Matador221C2, 227C3
Matagorda291A
McCamey233C3
McLean267C3
Memphis283A, 292A
Menard242A, 265C2
Mertzon278C2
Meyersville261A
Midway251A
Milano274A
Moody256A
Moran281A
Mount Enterprise279A
Muleshoe227C1
Munday270C1
Newcastle263A
Oakwood233A
Paducah234C3
Paint Rock296C3
Palacios264A
Pearsall227A
Port Isabel288A
Premont287A
Presidio292C1
Quanah251C3
Richland Springs235A, 299A
Rising Star290C3
Roaring Springs227A, 249C3
Robert Lee289A
Roby249A
Rocksprings291A
Rule253A
Sanderson274C1, 286C2
Santa Anna282A
Seymour222C2
Sheffield224C2
Silverton252A
Smiley280A
Sonora237C3, 272A
Spur260C3
Teague237C3
Turkey244C2, 269A
Van Alstyne*260A
Weinert266C3
Wells254A
Zapata292A
UTAH
Beaver259A
Milford288C
Toquerville280C
VERMONT
      
      
VIRGINIA
Alberta299A
Chincoteague233A
Shawsville273A
Shenandoah*296A
WASHINGTON
Chewelah*274C3
Coupeville266A
Dayton272A
Oak Harbor*233A, 277A
Sedro-Woolley289A
Sequim237A
WEST VIRGINIA
Marlinton292A
St Marys*287A
WISCONSIN
Ashland*275A
Augusta*268C3
Boscobel244C3
Crandon276A
Hayward*232C2
Laona272C3
New Holstein225A
Owen242C3
Tigerton295A
Tomahawk265C3
Two Rivers255A
Washburn*284A
WYOMING
Baggs277A
Bairoil235A
Dubois242C2
Jackson*294C2
Marbleton257C1
Meeteetse259C
Wheatland286A
AMERICAN SAMOA
CENTRAL MARIANAS
GARAPAN
GUAM
      
PUERTO RICO
Santa Isabel251A
VIRGIN ISLANDS
Charlotte Amalie*226A, 237B
   

(Sec. 316, 66 Stat. 717; 47 U.S.C. 316; sec. 5, 48 Stat., as amended, 1068; 47 U.S.C. 154, 155; secs. 2, 3, 4, 301, 303, 307, 308, 309, 315, 317, 48 Stat. as amended, 1064, 1065, 1066, 1081, 1082, 1083, 1084, 1085, 1088, 1089; (47 U.S.C. 152, 153, 301, 303, 307, 308, 309, 315, 317); secs 1, 201-205, 208, 215, 218, 313, 314, 403, 404, 410, 602; 48 Stat. as amended; 1070, 1071, 1072, 1073, 1076, 1077, 1087, 1094, 1098, 1102 (47 U.S.C. 151, 201-205, 208, 215, 218, 313, 314, 403, 404, 410, 602))

[30 FR 12711, Oct. 6, 1965]

Editorial Notes: 1. For Federal Register citations affecting §73.202 see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.

2. At 77 FR 50053, Aug. 20, 2012, §73.202(b), the Table of FM Allotments under California, was amended; however, the amendment could not be incorporated due to inaccurate amendatory instruction.

§73.203   Availability of channels.

(a) Except as provided for in paragraph (b) of this section and §1.401(d) of this chapter and 73.3573(a)(1), applications may be filed to construct new FM broadcast stations only at the communities and on the channels contained in the Table of Allotments (§73.202(b)).

(b) Applications filed on a first come, first served basis for the minor modification of an existing FM broadcast station may propose any change in channel and/or class and/or community not defined as major in §73.3573(a). Applications for a change in community of license must comply with the requirements set forth in §73.3573(g).

Note to §73.203: This section is limited to non-reserved band changes in channel and/or class and/or community. Applications requesting such changes must meet either the minimum spacing requirements of §73.207 at the site specified in the application, without resort to the provisions of the Commission's rules permitting short spaced stations as set forth in §§73.213 through 73.215, or demonstrate by a separate exhibit attached to the application the existence of a suitable allotment site that fully complies with §§73.207 and 73.315 without resort to §§73.213 through 73.215.

[71 FR 76219, Dec. 20, 2006]

§73.204   International agreements and other restrictions on use of channels.

See §§73.207, 73.220 and 73.1650.

[49 FR 10264, Mar. 20, 1984]

§73.205   Zones.

For the purpose of allotments and assignments, the United States is divided into three zones as follows:

(a) Zone I consists of that portion of the United States located within the confines of the following lines drawn on the United States Albers Equal Area Projection Map (based on standard parallels 291/2° and 451/2°; North American datum): Beginning at the most easterly point on the State boundary line between North Carolina and Virginia; thence in a straight line to a point on the Virginia-West Virginia boundary line located at north latitude 37°49 and west longitude 80°1230; thence westerly along the southern boundary lines of the States of West Virginia, Ohio, Indiana, and Illinois to a point at the junction of the Illinois, Kentucky, and Missouri State boundary lines; thence northerly along the western boundary line of the State of Illinois to a point at the junction of the Illinois, Iowa, and Wisconsin State boundary lines; thence easterly along the northern State boundary line of Illinois to the 90th meridian; thence north along this meridian to the 43.5° parallel; thence east along this parallel to the United States-Canada border; thence southerly and following that border until it again intersects the 43.5° parallel; thence east along this parallel to the 71st meridian; thence in a straight line to the intersection of the 69th meridian and the 45th parallel; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a city, the city shall be considered to be located in Zone I. (See Figure 1 of §73.699.)

(b) Zone I-A consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located south of the 40th parallel.

(c) Zone II consists of Alaska, Hawaii and the rest of the United States which is not located in either Zone I or Zone I-A.

[29 FR 14116, Oct. 14, 1964, and 31 FR 10125, July 27, 1966, as amended at 48 FR 29504, June 27, 1983]

§73.207   Minimum distance separation between stations.

(a) Except for assignments made pursuant to §73.213 or 73.215, FM allotments and assignments must be separated from other allotments and assignments on the same channel (co-channel) and five pairs of adjacent channels by not less than the minimum distances specified in paragraphs (b) and (c) of this section. The Commission will not accept petitions to amend the Table of Allotments unless the reference points meet all of the minimum distance separation requirements of this section. The Commission will not accept applications for new stations, or applications to change the channel or location of existing assignments unless transmitter sites meet the minimum distance separation requirements of this section, or such applications conform to the requirements of §73.213 or 73.215. However, applications to modify the facilities of stations with short-spaced antenna locations authorized pursuant to prior waivers of the distance separation requirements may be accepted, provided that such applications propose to maintain or improve that particular spacing deficiency. Class D (secondary) assignments are subject only to the distance separation requirements contained in paragraph (b)(3) of this section. (See §73.512 for rules governing the channel and location of Class D (secondary) assignments.)

(b) The distances listed in Tables A, B, and C apply to allotments and assignments on the same channel and each of five pairs of adjacent channels. The five pairs of adjacent channels are the first (200 kHz above and 200 kHz below the channel under consideration), the second (400 kHz above and below), the third (600 kHz above and below), the fifty-third (10.6 MHz above and below), and the fifty-fourth (10.8 MHz above and below). The distances in the Tables apply regardless of whether the proposed station class appears first or second in the “Relation” column of the table.

(1) Domestic allotments and assignments must be separated from each other by not less than the distances in Table A which follows:

Table A—Minimum Distance Separation Requirements in Kilometers (miles)

Relation Co-channel 200 kHz 400/600 kHz 10.6/10.8 MHz
A to A115 (71)72 (45)31 (19)10 (6)
A to B1143 (89)96 (60)48 (30)12 (7)
A to B178 (111)113 (70)69 (43)15 (9)
A to C3142 (88)89 (55)42 (26)12 (7)
A to C2166 (103)106 (66)55 (34)15 (9)
A to C1200 (124)133 (83)75 (47)22 (14)
A to C0215 (134)152 (94)86 (53)25 (16)
A to C226 (140)165 (103)95 (59)29 (18)
B1 to B1175 (109)114 (71)50 (31)14 (9)
B1 to B211 (131)145 (90)71 (44)17 (11)
B1 to C3175 (109)114 (71)50 (31)14 (9)
B1 to C2200 (124)134 (83)56 (35)17 (11)
B1 to C1233 (145)161 (100)77 (48)24 (15)
B1 to C0248 (154)180 (112)87 (54)27 (17)
B1 to C259 (161)193 (120)105 (65)31 (19)
B to B241 (150)169 (105)74 (46)20 (12)
B to C3211 (131)145 (90)71 (44)17 (11)
B to C2241 (150)169 (105)74 (46)20 (12)
B to C1270 (168)195 (121)79 (49)27 (17)
B to C0272 (169)214 (133)89 (55)31 (19)
B to C274 (170)217 (135)105 (65)35 (22)
C3 to C3153 (95)99 (62)43 (27)14 (9)
C3 to C2177 (110)117 (73)56 (35)17 (11)
C3 to C1211 (131)144 (90)76 (47)24 (15)
C3 to C0226 (140)163 (101)87 (54)27 (17)
C3 to C237 (147)176 (109)96 (60)31 (19)
C2 to C2190 (118)130 (81)58 (36)20 (12)
C2 to C1224 (139)158 (98)79 (49)27 (17)
C2 to C0239 (148)176 (109)89 (55)31 (19)
C2 to C249 (155)188 (117)105 (65)35 (22)
C1 to C1245 (152)177 (110)82 (51)34 (21)
C1 to C0259 (161)196 (122)94 (58)37 (23)
C1 to C270 (168)209 (130)105 (65)41 (25)
C0 to C0270 (168)207 (129)96 (60)41 (25)
C0 to C281 (175)220 (137)105 (65)45 (28)
C to C290 (180)241 (150)105 (65)48 (30)

(2) Under the Canada-United States FM Broadcasting Agreement, domestic U.S. allotments and assignments within 320 kilometers (199 miles) of the common border must be separated from Canadian allotments and assignments by not less than the distances given in Table B, which follows. When applying Table B, U.S. Class C2 allotments and assignments are considered to be Class B; also, U.S. Class C3 allotments and assignments and U.S. Class A assignments operating with more than 3 kW ERP and 100 meters antenna HAAT (or equivalent lower ERP and higher antenna HAAT based on a class contour distance of 24 km) are considered to be Class B1.

Table B—Minimum Distance Separation Requirements in Kilometers

RelationCo-ChannelAdjacent ChannelsI.F.
0 kHz200 kHz400 kHz600 kHz10.6/10.8 MHz
A-A1328545378
A-B1180113625416
A-B206132766916
A-C1239164989032
A-C24217710810032
B1-B1197131705724
B1-B223149847124
B1-C12561811069240
B1-C25919511610340
B-B237164947424
               
B-C12711951159540
B-C27420912510640
C1-C129221713410148
C1-C30223014411148
C-C30624115311348

(3) Under the 1992 Mexico-United States FM Broadcasting Agreement, domestic U.S. assignments or allotments within 320 kilometers (199 miles) of the common border must be separated from Mexican assignments or allotments by not less than the distances given in Table C in this paragraph (b)(3). When applying Table C—

(i) U.S. or Mexican assignments or allotments which have been notified internationally as Class A are limited to a maximum of 3.0 kW ERP at 100 meters HAAT, or the equivalent;

(ii) U.S. or Mexican assignments or allotments which have been notified internationally as Class AA are limited to a maximum of 6.0 kW ERP at 100 meters HAAT, or the equivalent;

(iii) U.S. Class C3 assignments or allotments are considered Class B1;

(iv) U.S. Class C2 assignments or allotments are considered Class B; and

(v) Class C1 assignments or allotments assume maximum facilities of 100 kW ERP at 300 meters HAAT. However, U.S. Class C1 stations may not, in any event, exceed the domestic U.S. limit of 100 kW ERP at 299 meters HAAT, or the equivalent.

Table C—Minimum Distance Separation Requirements in Kilometers

RelationCo-Channel200 kHz400 kHz or 600 kHz10.6 or 10.8 MHz (I.F.)
A to A10061258
A to AA11168319
A to B1138884811
A to B1631056514
A to C11961297421
A to C2101619428
AA to AA115723110
AA to B1143964812
AA to B1781256915
AA to C12001337522
AA to C2261659529
B1 to B11751145014
B1 to B2111457117
B1 to C12331617724
B1 to C2591939631
B to B2371646520
B to C12701957927
B to C2702159835
C1 to C12451778234
C1 to C27020910241
C to C29022810548

(c) The distances listed below apply only to allotments and assignments on Channel 253 (98.5 MHz). The Commission will not accept petitions to amend the Table of Allotments, applications for new stations, or applications to change the channel or location of existing assignments where the following minimum distances (between transmitter sites, in kilometers) from any TV Channel 6 allotment or assignment are not met:

Minimum Distance Separation From TV Channel 6 (82-88 MHz)

FM ClassTV Zone ITV Zones II & III
A1722
B11923
B2226
C31923
C22226
C12933
C3641

[48 FR 29504, June 27, 1983, as amended at 49 FR 10264, Mar. 20, 1984; 49 FR 19670, May 9, 1984; 49 FR 50047, Dec. 26, 1984; 51 FR 26250, July 22, 1986; 54 FR 14963, Apr. 14, 1989; 54 FR 16366, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35338, Aug. 25, 1989; 56 FR 27426, June 14, 1991; 56 FR 57293, Nov. 8, 1991; 62 FR 50256, Sept. 25, 1997; 65 FR 79776, Dec. 20, 2000]

§73.208   Reference points and distance computations.

(a)(1) The following reference points must be used to determine distance separation requirements when petitions to amend the Table of Allotments (§73.202(b)) are considered:

(i) First, transmitter sites if authorized, or if proposed in applications with cut-off protection pursuant to paragraph (a)(3) of this section;

(ii) Second, reference coordinates designated by the FCC;

(iii) Third, coordinates listed in the United States Department of Interior publication entitled Index to the National Atlas of the United States of America; or

(iv) Last, coordinates of the main post office.

(The community's reference points for which the petition is submitted will normally be the coordinates listed in the above publication.)

(2) When the distance between communities is calculated using community reference points and it does not meet the minimum separation requirements of §73.207, the channel may still be allotted if a transmitter site is available that would meet the minimum separation requirements and still permit the proposed station to meet the minimum field strength requirements of §73.315. A showing indicating the availability of a suitable site should be sumitted with the petition. In cases where a station is not authorized in a community or communities and the proposed channel cannot meet the separation requirement a showing should also be made indicating adequate distance between suitable transmitter sites for all communities.

(3) Petitions to amend the Table of Allotments that do not meet minimum distance separation requirements to transmitter sites specified in pending applications will not be considered unless they are filed no later than:

(i) The last day of a filing window if the application is for a new FM facility or a major change in the non-reserved band and is filed during a filing window established under section 73.3564(d)(3); or

(ii) The cut-off date established in a Commission Public Notice under §73.3564(d) and 73.3573(e) if the application is for a new FM facility or a major change in the reserved band; or

(iii) The date of receipt of all other types of FM applications. If an application is amended so as to create a conflict with a petition for rule making filed prior to the date the amendment is filed, the amended application will be treated as if filed on the date of the amendment for purposes of this paragraph (a)(3).

Note: If the filing of a conflicting FM application renders an otherwise timely filed counterproposal unacceptable, the counterproposal may be considered in the rulemaking proceeding if it is amended to protect the site of the previously filed FM application within 15 days after being placed on the Public Notice routinely issued by the staff concerning the filing of counterproposals. No proposals involving communities not already included in the proceeding can be introduced during the reply comment period as a method of resolving conflicts. The counterproponent is required to make a showing that, at the time it filed the counterproposal, it did not know, and could not have known by exercising due diligence, of the pendency of the conflicting FM application.

(b) Station separations in licensing proceedings shall be determined by the distance between the coordinates of the proposed transmitter site in one community and

(1) The coordinates of an authorized transmitter site for the pertinent channel in the other community; or, where such transmitter site is not available for use as a reference point,

(2) Reference coordinates designated by the FCC; or, if none are designated,

(3) The coordinates of the other community as listed in the publication listed in paragraph (a) of this section; or, if not contained therein,

(4) The coordinates of the main post office of such other community.

(5) In addition, where there are pending applications in other communities which, if granted, would have to be considered in determining station separations, the coordinates of the transmitter sites proposed in such applications must be used to determine whether the requirements with respect to minimum separations between the proposed stations in the respective cities have been met.

(c) The method given in this paragraph shall be used to compute the distance between two reference points, except that, for computation of distance involving stations in Canada and Mexico, the method for distance computation specified in the applicable international agreement shall be used instead. The method set forth in this paragraph is valid only for distances not exceeding 475 km (295 miles).

(1) Convert the latitudes and longitudes of each reference point from degree-minute-second format to degree-decimal format by dividing minutes by 60 and seconds by 3600, then adding the results to degrees.

(2) Calculate the middle latitude between the two reference points by averaging the two latitudes as follows:

ML=(LAT1dd+LAT2dd)÷2

(3) Calculate the number of kilometers per degree latitude difference for the middle latitude calculated in paragraph (c)(2) as follows:

KPDlat=111.13209−0.56605 cos(2ML)+0.00120 cos(4ML)

(4) Calculate the number of kilometers per degree longitude difference for the middle latitude calculated in paragraph (c)(2) as follows:

KPDlon=111.41513 cos(ML)−0.09455 cos(3ML)+0.00012 cos(5ML)

(5) Calculate the North-South distance in kilometers as follows:

NS=KPDlat(LAT1dd−LAT2dd)

(6) Calculate the East-West distance in kilometers as follows:

EW=KPDlon(LON1dd−LON2dd)

(7) Calculate the distance between the two reference points by taking the square root of the sum of the squares of the East-West and North-South distances as follows:

DIST=(NS2 + EW2)0.5

(8) Round the distance to the nearest kilometer.

(9) Terms used in this section are defined as follows:

(i) LAT1dd and LON1dd=the coordinates of the first reference point in degree-decimal format.

(ii) LAT2dd and LON2dd=the coordinates of the second reference point in degree-decimal format.

(iii) ML=the middle latitude in degree-decimal format.

(iv) KPDlat=the number of kilometers per degree of latitude at a given middle latitude.

(v) KPDlon=the number of kilometers per degree of longitude at a given middle latitude.

(vi) NS=the North-South distance in kilometers.

(vii) EW=the East-West distance in kilometers.

(viii) DIST=the distance between the two reference points, in kilometers.

[28 FR 13623, Dec. 14, 1963, as amended at 29 FR 14116, Oct. 14, 1964; 48 FR 29505, June 27, 1983; 52 FR 37788, Oct. 9, 1987; 52 FR 39920, Oct. 26, 1987; 54 FR 9806, Mar. 8, 1989; 57 FR 36020, Aug. 12, 1992; 58 FR 38537, July 19, 1993]

§73.209   Protection from interference.

(a) Permittees and licensees of FM broadcast stations are not protected from any interference which may be caused by the grant of a new station, or of authority to modify the facilities of an existing station, in accordance with the provisions of this subpart. However, they are protected from interference caused by Class D (secondary) noncommercial educational FM stations. See §73.509.

(b) The nature and extent of the protection from interference afforded FM broadcast stations operating on Channels 221-300 is limited to that which results when assignments are made in accordance with the rules in this subpart.

(c) Permittees and licensees of FM stations are not protected from interference which may be caused by the grant of a new LPFM station or of authority to modify an existing LPFM station, except as provided in subpart G of this part.

[43 FR 39715, Sept. 6, 1978 and 48 FR 29505, June 27, 1983; 54 FR 9802, Mar. 8, 1989; 65 FR 7640, Feb. 15, 2000; 65 FR 67299, Nov. 9, 2000]

§73.210   Station classes.

(a) The rules applicable to a particular station, including minimum and maximum facilities requirements, are determined by its class. Possible class designations depend upon the zone in which the station's transmitter is located, or proposed to be located. The zones are defined in §73.205. Allotted station classes are indicated in the Table of Allotments, §73.202. Class A, B1 and B stations may be authorized in Zones I and I-A. Class A, C3, C2, C1, C0 and C stations may be authorized in Zone II.

(b) The power and antenna height requirements for each class are set forth in §73.211. If a station has an ERP and an antenna HAAT such that it cannot be classified using the maximum limits and minimum requirements in §73.211, its class shall be determined using the following procedure:

(1) Determine the reference distance of the station using the procedure in paragraph (b)(1)(i) of §73.211. If this distance is less than or equal to 28 km, the station is Class A; otherwise,

(2) For a station in Zone I or Zone I-A, except for Puerto Rico and the Virgin Islands:

(i) If this distance is greater than 28 km and less than or equal to 39 km, the station is Class B1.

(ii) If this distance is greater than 39 km and less than or equal to 52 km, the station is Class B.

(3) For a station in Zone II:

(i) If this distance is greater than 28 km and less than or equal to 39 km, the station is Class C3.

(ii) If this distance is greater than 39 km and less than or equal to 52 km, the station is Class C2.

(iii) If this distance is greater than 52 km and less than or equal to 72 km, the station is Class C1.

(iv) If this distance is greater than 72 km and less than or equal to 83 km, the station is Class C0.

(v) If this distance is greater than 83 km and less than or equal to 92 km, the station is Class C.

(4) For a station in Puerto Rico or the Virgin Islands:

(i) If this distance is less than or equal to 42 km, the station is Class A.

(ii) If this distance is greater than 42 km and less than or equal to 46 km, the station is Class B1.

(iii) If this distance is greater then 46 km and less than or equal to 78 km, the station is Class B.

[52 FR 37788, Oct. 9, 1987; 52 FR 39920, Oct. 26, 1987, as amended at 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35339, Aug. 25, 1989; 65 FR 79777, Dec. 20, 2000]

§73.211   Power and antenna height requirements.

(a) Minimum requirements. (1) Except as provided in paragraphs (a)(3) and (b)(2) of this section, FM stations must operate with a minimum effective radiated power (ERP) as follows:

(i) The minimum ERP for Class A stations is 0.1 kW.

(ii) The ERP for Class B1 stations must exceed 6 kW.

(iii) The ERP for Class B stations must exceed 25 kW.

(iv) The ERP for Class C3 stations must exceed 6 kW.

(v) The ERP for Class C2 stations must exceed 25 kW.

(vi) The ERP for Class C1 stations must exceed 50 kW.

(vii) The minimum ERP for Class C and C0 stations is 100 kW.

(2) Class C0 stations must have an antenna height above average terrain (HAAT) of at least 300 meters (984 feet). Class C stations must have an antenna height above average terrain (HAAT) of at least 451 meters (1480 feet).

(3) Stations of any class except Class A may have an ERP less than that specified in paragraph (a)(1) of this section, provided that the reference distance, determined in accordance with paragraph (b)(1)(i) of this section, exceeds the distance to the class contour for the next lower class. Class A stations may have an ERP less than 100 watts provided that the reference distance, determined in accordance with paragraph (b)(1)(i) of this section, equals or exceeds 6 kilometers.

(b) Maximum limits. (1) Except for stations located in Puerto Rico or the Virgin Islands, the maximum ERP in any direction, reference HAAT, and distance to the class contour for each FM station class are listed below:

Station class Maximum ERP Reference HAAT in meters (ft.) Class contour distance in kilometers
A6 kW (7.8 dBk)100 (328)28
B125 kW (14.0 dBk)100 (328)39
B50 kW (17.0 dBk)150 (492)52
C325 kW (14.0 dBk)100 (328)39
C250 kW (17.0 dBk)150 (492)52
C1100 kW (20.0 dBk)299 (981)72
C0100 kW (20.0 dBk)450 (1476)83
C100 kW (20.0 dBk)600 (1968)92

(i) The reference distance of a station is obtained by finding the predicted distance to the 1mV/m contour using Figure 1 of §73.333 and then rounding to the nearest kilometer. Antenna HAAT is determined using the procedure in §73.313. If the HAAT so determined is less than 30 meters (100 feet), a HAAT of 30 meters must be used when finding the predicted distance to the 1 mV/m contour.

(ii) If a station's ERP is equal to the maximum for its class, its antenna HAAT must not exceed the reference HAAT, regardless of the reference distance. For example, a Class A station operating with 6 kW ERP may have an antenna HAAT of 100 meters, but not 101 meters, even though the reference distance is 28 km in both cases.

(iii) Except as provided in paragraph (b)(3) of this section, no station will be authorized in Zone I or I-A with an ERP equal to 50 kW and a HAAT exceeding 150 meters. No station will be authorized in Zone II with an ERP equal to 100 kW and a HAAT exceeding 600 meters.

(2) If a station has an antenna HAAT greater than the reference HAAT for its class, its ERP must be lower than the class maximum such that the reference distance does not exceed the class contour distance. If the antenna HAAT is so great that the station's ERP must be lower than the minimum ERP for its class (specified in paragraphs (a)(1) and (a)(3) of this section), that lower ERP will become the minimum for that station.

(3) For stations located in Puerto Rico or the Virgin Islands, the maximum ERP in any direction, reference HAAT, and distance to the class contour for each FM station class are listed below:

Station classMaximum ERPReference HAAT in meters (ft.)Class contour distance in kilometers
A6kW (7.8 dBk)240 (787)42
B125kW (14.0 dBk)150 (492)46
B50kW (17.0 dBk)472 (1549)78

(c) Existing stations. Stations authorized prior to March 1, 1984 that do not conform to the requirements of this section may continue to operate as authorized. Stations operating with facilities in excess of those specified in paragraph (b) of this section may not increase their effective radiated powers or extend their 1 mV/m field strength contour beyond the location permitted by their present authorizations. The provisions of this section will not apply to applications to increase facilities for those stations operating with less than the minimum power specified in paragraph (a) of this section.

(d) Existing Class C stations below minimum antenna HAAT. Class C stations authorized prior to January 19, 2001 that do not meet the minimum antenna HAAT specified in paragraph (a)(2) of this section for Class C stations may continue to operate as authorized subject to the reclassification procedures set forth in Note 4 to §73.3573.

[53 FR 17042, May 13, 1988, as amended at 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35339, Aug. 25, 1989; 65 FR 79777, Dec. 20, 2000]

§73.212   Administrative changes in authorizations.

(a) In the issuance of FM broadcast station authorizations, the Commission will specify the transmitter output power and effective radiated power in accordance with the following tabulation:

Power (watts or kW)Rounded out to nearest figure (watts or kW)
1 to 3.05
3 to 10.1
10 to 30.5
30 to 1001
100 to 3005
300 to 1,00010

(b) Antenna heights above average terrain will be rounded out to the nearest meter.

[28 FR 13623, Dec. 14, 1963, as amended at 48 FR 29506, June 27, 1983]

§73.213   Grandfathered short-spaced stations.

(a) Stations at locations authorized prior to November 16, 1964, that did not meet the separation distances required by §73.207 and have remained continuously short-spaced since that time may be modified or relocated with respect to such short-spaced stations, provided that (i) any area predicted to receive interference lies completely within any area currently predicted to receive co-channel or first-adjacent channel interference as calculated in accordance with paragraph (a)(1) of this section, or that (ii) a showing is provided pursuant to paragraph (a)(2) of this section that demonstrates that the public interest would be served by the proposed changes.

(1) The F(50,50) curves in Figure 1 of §73.333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain, as calculated pursuant to §73.313(c), (d)(2) and (d)(3), using data for as many radials as necessary, to determine the location of the desired (service) field strength. The F(50,10) curves in Figure 1a of §73.333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain, as calculated pursuant to §73.313(c), (d)(2) and (d)(3), using data for as many radials as necessary, to determine the location of the undesired (interfering) field strength. Predicted interference is defined to exist only for locations where the desired (service) field strength exceeds 0.5 mV/m (54 dBu) for a Class B station, 0.7 mV/m (57 dBu) for a Class B1 station, and 1 mV/m (60 dBu) for any other class of station.

(i) Co-channel interference is predicted to exist, for the purpose of this section, at all locations where the undesired (interfering station) F(50,10) field strength exceeds a value 20 dB below the desired (service) F(50,50) field strength of the station being considered (e.g., where the protected field strength is 60 dBu, the interfering field strength must be 40 dBu or more for predicted interference to exist).

(ii) First-adjacent channel interference is predicted to exist, for the purpose of this section, at all locations where the undesired (interfering station) F(50,10) field strength exceeds a value 6 dB below the desired (service) F(50,50) field strength of the station being considered (e.g., where the protected field strength is 60 dBu, the interfering field strength must be 54 dBu or more for predicted interference to exist).

(2) For co-channel and first-adjacent channel stations, a showing that the public interest would be served by the changes proposed in an application must include exhibits demonstrating that the total area and population subject to co-channel or first-adjacent channel interference, caused and received, would be maintained or decreased. In addition, the showing must include exhibits demonstrating that the area and the population subject to co-channel or first-adjacent channel interference caused by the proposed facility to each short-spaced station individually is not increased. In all cases, the applicant must also show that any area predicted to lose service as a result of new co-channel or first-adjacent-channel interference has adequate aural service remaining. For the purpose of this section, adequate service is defined as 5 or more aural services (AM or FM).

(3) For co-channel and first-adjacent-channel stations, a copy of any application proposing interference caused in any areas where interference is not currently caused must be served upon the licensee(s) of the affected short-spaced station(s).

(4) For stations covered by this paragraph (a), there are no distance separation or interference protection requirements with respect to second-adjacent and third-adjacent channel short-spacings that have existed continuously since November 16, 1964.

(b) Stations at locations authorized prior to May 17, 1989, that did not meet the IF separation distances required by §73.207 and have remained short-spaced since that time may be modified or relocated provided that the overlap area of the two stations' 36 mV/m field strength contours is not increased.

(c) Short spacings involving at least one Class A allotment or authorization. Stations that became short spaced on or after November 16, 1964 (including stations that do not meet the minimum distance separation requirements of paragraph (c)(1) of this section and that propose to maintain or increase their existing distance separations) may be modified or relocated in accordance with paragraph (c)(1) or (c)(2) of this section, except that this provision does not apply to stations that became short spaced by grant of applications filed after October 1, 1989, or filed pursuant to §73.215. If the reference coordinates of an allotment are short spaced to an authorized facility or another allotment (as a result of the revision of §73.207 in the Second Report and Order in MM Docket No. 88-375), an application for the allotment may be authorized, and subsequently modified after grant, in accordance with paragraph (c)(1) or (c)(2) of this section only with respect to such short spacing. No other stations will be authorized pursuant to these paragraphs.

(1) Applications for authorization under requirements equivalent to those of prior rules. Each application for authority to operate a Class A station with no more than 3000 watts ERP and 100 meters antenna HAAT (or equivalent lower ERP and higher antenna HAAT based on a class contour distance of 24 km) must specify a transmitter site that meets the minimum distance separation requirements in this paragraph. Each application for authority to operate a Class A station with more than 3000 watts ERP (up to a maximum of 5800 watts), but with an antenna HAAT lower than 100 meters such that the distance to the predicted 0.05 mV/m (34 dBµV/m) F(50,10) field strength contour does not exceed 98 km must specify a transmitter site that meets the minimum distance separation requirements in this paragraph. Each application for authority to operate an FM station of any class other than Class A must specify a transmitter site that meets the minimum distance separation requirements in this paragraph with respect to Class A stations operating pursuant to this paragraph or paragraph (c)(2) of this section, and that meets the minimum distance separation requirements of §73.207 with respect to all other stations.

Minimum Distance Separation Requirements in Kilometers (miles)

RelationCo-channel200 kHz400/600 kHz10.6/10.8 MHz
A to A105 (65)64 (40)27 (17)8 (5)
A to B1138 (86)88 (55)48 (30)11 (6)
A to B163 (101)105 (65)69 (43)14 (9)
A to C3138 (86)84 (52)42 (26)11 (6)
A to C2163 (101)105 (65)55 (34)14 (9)
A to C1196 (122)129 (80)74 (46)21 (13)
A to C222 (138)161 (100)94 (58)28 (17)

(2) Applications for authorization of Class A facilities greater than 3,000 watts ERP and 100 meters HAAT. Each application to operate a Class A station with an ERP and HAAT such that the reference distance would exceed 24 kilometers must contain an exhibit demonstrating the consent of the licensee of each co-channel, first, second or third adjacent channel station (for which the requirements of §73.207 are not met) to a grant of that application. Each such application must specify a transmitter site that meets the applicable IF-related channel distance separation requirements of §73.207. Applications that specify a new transmitter site which is short-spaced to an FM station other than another Class A station which is seeking a mutual increase in facilities may be granted only if no alternative fully-spaced site or less short-spaced site is available. Licensees of Class A stations seeking mutual increases in facilities need not show that a fully spaced site or less short-spaced site is available. Applications submitted pursuant to the provisions of this paragraph may be granted only if such action is consistent with the public interest.

[52 FR 37789, Oct. 9, 1987, as amended at 54 FR 14964, Apr. 14, 1989; 54 FR 35339, Aug. 25, 1989; 56 FR 27426, June 14, 1991; 62 FR 50521, Sept. 26, 1997; 63 FR 33876, June 22, 1998]

§73.215   Contour protection for short-spaced assignments.

The Commission will accept applications that specify short-spaced antenna locations (locations that do not meet the domestic co-channel and adjacent channel minimum distance separation requirements of §73.207); Provided That, such applications propose contour protection, as defined in paragraph (a) of this section, with all short-spaced assignments, applications and allotments, and meet the other applicable requirements of this section. Each application to be processed pursuant to this section must specifically request such processing on its face, and must include the necessary exhibit to demonstrate that the requisite contour protection will be provided. Such applications may be granted when the Commission determines that such action would serve the public interest, convenience, and necessity.

(a) Contour protection. Contour protection, for the purpose of this section, means that on the same channel and on the first, second and third adjacent channels, the predicted interfering contours of the proposed station do not overlap the predicted protected contours of other short-spaced assignments, applications and allotments, and the predicted interfering contours of other short-spaced assignments, applications and allotments do not overlap the predicted protected contour of the proposed station.

(1) The protected contours, for the purpose of this section, are defined as follows. For all Class B and B1 stations on Channels 221 through 300 inclusive, the F(50,50) field strengths along the protected contours are 0.5 mV/m (54 dBµ) and 0.7 mV/m (57 dBµ), respectively. For all other stations, the F(50,50) field strength along the protected contour is 1.0 mV/m (60 dBµ).

(2) The interfering contours, for the purpose of this section, are defined as follows. For co-channel stations, the F(50,10) field strength along the interfering contour is 20 dB lower than the F(50,50) field strength along the protected contour for which overlap is prohibited. For first adjacent channel stations (±200 kHz), the F(50,10) field strength along the interfering contour is 6 dB lower than the F(50,50) field strength along the protected contour for which overlap is prohibited. For both second and third adjacent channel stations (±400 kHz and ±600 kHz), the F(50,10) field strength along the interfering contour is 40 dB higher than the F(50,50) field strength along the protected contour for which overlap is prohibited.

(3) The locations of the protected and interfering contours of the proposed station and the other short-spaced assignments, applications and allotments must be determined in accordance with the procedures of paragraphs (c), (d)(2) and (d)(3) of §73.313, using data for as many radials as necessary to accurately locate the contours.

(4) Protected and interfering contours (in dBu) for stations in Puerto Rico and the U.S. Virgin Islands are as follows:

Station with interfering contour Station with protected contour
Class A Class B1 Class B
Interfering Protected Interfering Protected Interfering Protected
Co-Channel:
Class A466641614060
Class B1436339593858
Class B456541614161
1st Adj. Channel:
Class A616756625965
Class B1576354605460
Class B626856625763
2nd-3rd Adj. Channel:
Class A107671006010464
Class B199591006010464
Class B9454945410464

Maximum permitted facilities assumed for each station pursuant to 47 CFR 73.211(b)(3):

6 kW ERP/240 meters HAAT—Class A

25 kW ERP/150 meters HAAT—Class B1

50 kW ERP/472 meters HAAT—Class B

(b) Applicants requesting short-spaced assignments pursuant to this section must take into account the following factors in demonstrating that contour protection is achieved:

(1) The ERP and antenna HAAT of the proposed station in the direction of the contours of other short-spaced assignments, applications and allotments. If a directional antenna is proposed, the pattern of that antenna must be used to calculate the ERP in particular directions. See §73.316 for additional requirements for directional antennas.

(2) The ERP and antenna HAAT of other short-spaced assignments, applications and allotments in the direction of the contours of the proposed station. The ERP and antenna HAATs in the directions of concern must be determined as follows:

(i) For vacant allotments, contours are based on the presumed use, at the allotment's reference point, of the maximum ERP that could be authorized for the station class of the allotment, and antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the station class of the allotment.

(ii) For existing stations that were not authorized pursuant to this section, including stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, and for applications not requesting authorization pursuant to this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and the antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply (e.g. zoning laws, FAA constraints, application of §73.213).

(iii) For stations authorized pursuant to this section, except stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, contours are based on the use of the authorized ERP in the directions of concern, and HAATs in the directions of concern derived from the authorized standard eight-radial antenna HAAT. For stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, authorized under this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply.

(iv) For applications containing a request for authorization pursuant to this section, except for applications to continue operation with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, contours are based on the use of the proposed ERP in the directions of concern, and antenna HAATs in the directions of concern derived from the proposed standard eight-radial antenna HAAT. For applications to continue operation with an ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial HAAT employed, if processing is requested under this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and antenna HAATs in the directions of concern that would result from a nondirectional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply.

Note to paragraph (b): Applicants are cautioned that the antenna HAAT in any particular direction of concern will not usually be the same as the standard eight-radial antenna HAAT or the reference HAAT for the station class.

(c) Applications submitted for processing pursuant to this section are not required to propose contour protection of any assignment, application or allotment for which the minimum distance separation requirements of §73.207 are met, and may, in the directions of those assignments, applications and allotments, employ the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed.

(d) Stations authorized pursuant to this section may be subsequently authorized on the basis of compliance with the domestic minimum separation distance requirements of §73.207, upon filing of an FCC Form 301 or FCC Form 340 (as appropriate) requesting a modification of authorization.

(e) The Commission will not accept applications that specify a short-spaced antenna location for which the following minimum distance separation requirements, in kilometers (miles), are not met:

Relation Co-Channel 200 kHz 400/600 kHz
A to A92 (57)49 (30)25 (16)
A to B1119 (74)72 (45)42 (26)
A to B143 (89)96 (60)63 (39)
A to C3119 (74)72 (45)36 (22)
A to C2143 (89)89 (55)49 (30)
A to C1178 (111)111 (69)69 (43)
A to C0193 (120)130 (81)80 (50)
A to C203 (126)142 (88)89 (55)
B1 to B1143 (89)96 (60)44 (27)
B1 to B178 (111)114 (71)65 (40)
B1 to C3143 (89)96 (60)44 (27)
B1 to C2175 (109)114 (71)50 (31)
B1 to C1200 (124)134 (83)71 (44)
B1 to C00215 (134)153 (95)81 (50)
B1 to C233 (145)165 (103)99 (61)
B to B211 (131)145 (90)68 (42)
B to C3178 (111)114 (70)65 (40)
B to C2211 (131)145 (90)68 (42)
B to C1241 (150)169 (105)73 (45)
B to C0266 (165)195 (121)83 (52)
B to C268 (163)195 (121)99 (61)
C3 to C3142 (88)89 (55)37 (23)
C3 to C2166 (103)106 (66)50 (31)
C3 to C1200 (124)133 (83)70 (43)
C3to C0215 (134)152 (94)81 (50)
C3 to C226 (140)165 (103)90 (56)
C2 to C2177 (110)117 (73)52 (32)
C2 to C1211 (131)144 (90)73 (45)
C2 to C0227 (141)163 (101)83 (52)
C2 to C237 (147)176 (109)96 (61)
C1 to C1224 (139)158 (98)76 (47)
C1 to C0239 (148)176 (109)88 (55)
C1 to C249 (155)188 (117)99 (61)
C0 to C0259 (161)196 (122)90 (56)
C0 to C270 (168)207 (12999 (61)
C to C270 (168)209 (130)99 (61)

[54 FR 9802, Mar. 8, 1989, as amended at 54 FR 35340, Aug. 25, 1989; 56 FR 57294, Nov. 8, 1991; 57 FR 46325, Oct. 8, 1992; 65 FR 79777, Dec. 20, 2000; 66 FR 8149, Jan. 29, 2001]

§73.220   Restrictions on use of channels.

(a) The frequency 89.1 MHz (channel 206) is revised in the New York City metropolitan area for the use of the United Nations with the equivalent of an antenna height of 150 meters (492 feet) above average terrain and effective radiated power of 20 kWs, and the FCC will make no assignments which would cause objectionable interference with such use.

(b) [Reserved]

[43 FR 45845, Oct. 4, 1978, as amended at 46 FR 50376, Oct. 13, 1981, 47 FR 30068, July 12, 1982; 48 FR 29507, June 27, 1983; 70 FR 46676, Aug. 10, 2005]

§73.232   Territorial exclusivity.

No licensee of an FM broadcast station shall have any arrangement with a network organization which prevents or hinders another station serving substantially the same area from broadcasting the network's programs not taken by the former station, or which prevents or hinders another station serving a substantially different area from broadcasting any program of the network organization: Provided, however, That this section does not prohibit arrangements under which the station is granted first call within its primary service area upon the network's programs. The term “network organization” means any organization originating program material, with or without commercial messages, and furnishing the same to stations interconnected so as to permit simultaneous broadcast by all or some of them. However, arrangements involving only stations under common ownership, or only the rebroadcast by one station of programming from another with no compensation other than a lump-sum payment by the station rebroadcasting, are not considered arrangements with a network organization. The term “arrangement“ means any contract, arrangement or understanding, express or implied.

[42 FR 16422, Mar. 28, 1977, as amended at 57 FR 48333, Oct. 23, 1992]

§73.239   Use of common antenna site.

No FM broadcast station license or renewal of FM broadcast station license will be granted to any person who owns, leases, or controls a particular site which is peculiarly suitable for FM broadcasting in a particular area and (a) which is not available for use by other FM broadcast station licensees; and (b) no other comparable site is available in the area; and (c) where the exclusive use of such site by the applicant or licensee would unduly limit the number of FM broadcast stations that can be authorized in a particular area or would unduly restrict competition among FM broadcast stations.

[28 FR 13623, Dec. 14, 1963]

§73.258   Indicating instruments.

(a) Each FM broadcast station shall be equipped with indicating instruments which conform with the specifications described in §73.1215 for determining power by the indirect method; for indicating the relative amplitude of the transmission line radio frequency current, voltage, or power; and with such other instruments as are necessary for the proper adjustment, operation, and maintenance of the transmitting system.

(b) The function of each instrument shall be clearly and permanently shown in the instrument itself or on the panel immediately adjacent thereto.

(c) In the event that any one of these indicating instruments becomes defective when no substitute which conforms with the required specifications is available, the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the FCC: Provided that, if the defective instrument is the transmission line meter of a station which determines the output power by the direct method, the operating power shall be determined by the indirect method in accordance with §73.267(c) during the entire time the station is operated without the transmission line meter.

(d) If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period, an informal letter request in accordance with §73.3549 may be filed with the FCC, Attention: Audio Division, Media Bureau, in Washington, DC for such additional time as may be required to complete repairs of the defective instrument.

[41 FR 36818, Sept. 1, 1976, as amended at 48 FR 44805, Sept. 30, 1983; 50 FR 32416, Aug. 12, 1985; 63 FR 33876, June 22, 1998; 67 FR 13231, Mar. 21, 2002]

§73.267   Determining operating power.

(a) The operating power of each FM station is to be determined by either the direct or indirect method.

(b) Direct method. The direct method of power determination for an FM station uses the indications of a calibrated transmission line meter (responsive to relative voltage, current, or power) located at the RF output terminals of the transmitter. This meter must be calibrated whenever there is any indication that the calibration is inaccurate or whenever any component of the metering circuit is repaired or replaced. The calibration must cover, as a minimum, the range from 90% to 105% of authorized power. The meter calibration may be checked by measuring the power at the transmitter terminals while either:

(1) Operating the transmitter into the transmitting antenna, and determining actual operating power by the indirect method described in §73.267(c); or

(2) Operating the transmitter into a load (of substantially zero reactance and a resistance equal to the transmission line characteristic impedance) and using an electrical device (within ±5% accuracy) or temperature and coolant flow indicator (within ±4% accuracy) to determine the power.

(3) The calibration must cover, as a minimum, the range from 90% to 105% of authorized power and the meter must provide clear indications which will permit maintaining the operating power within the prescribed tolerance or the meter shall be calibrated to read directly in power units.

(c) Indirect method. The operating power is determined by the indirect method by applying an appropriate factor to the input power to the last radio-frequency power amplifier stage of the transmitter, using the following formula:

Transmitter output power=Ep × Ip × F

Where:

Ep=DC input voltage of final radio stage.

Ip=Total DC input current of final radio stage.

F=Efficiency factor.

(1) If the above formula is not appropriate for the design of the transmitter final amplifier, use a formula specified by the transmitter manufacturer with other appropriate operating parameters.

(2) The value of the efficiency factor, F, established for the authorized transmitter output power is to be used for maintaining the operating power, even though there may be some variation in F over the power operating range of the transmitter.

(3) The value of F is to be determined and a record kept thereof by one of the following procedures listed in order of preference:

(i) Using the most recent measurement data for calibration of the transmission line meter according to the procedures described in paragraph (b) of this section or the most recent measurements made by the licensee establishing the value of F. In the case of composite transmitters or those in which the final amplifier stages have been modified pursuant to FCC approval, the licensee must furnish the FCC and also retain with the station records the measurement data used as a basis for determining the value of F.

(ii) Using measurement data shown on the transmitter manufacturer's test data supplied to the licensee; Provided, That measurements were made at the authorized frequency and transmitter output power.

(iii) Using the transmitter manufacturer's measurement data submitted to the FCC for type acceptance and as shown in the instruction book supplied to the licensee.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[44 FR 58731, Oct. 11, 1979, as amended at 45 FR 28141, Apr. 28, 1980; 48 FR 38479, Aug. 24, 1983; 49 FR 4210, Feb. 3, 1984; 49 FR 49851, Dec. 24, 1984]

§73.277   Permissible transmissions.

(a) No FM broadcast licensee or permittee shall enter into any agreement, arrangement or understanding, oral or written, whereby it undertakes to supply, or receives consideration for supplying, on its main channel a functional music, background music, or other subscription service (including storecasting) for reception in the place or places of business of any subscriber.

(b) The transmission (or interruption) of radio energy in the FM broadcast band is permissible only pursuant to a station license, program test authority, construction permit, or experimental authorization and the provisions of this part of the rules.

[29 FR 7471, June 10, 1964. Redesignated at 39 FR 38655, Nov. 1, 1974 and amended at 48 FR 28454, June 22, 1983]

§73.293   Use of FM multiplex subcarriers.

Licensees of FM broadcast stations may transmit, without further authorization, subcarrier communication services in accordance with the provisions of §§73.319 and 73.322.

[51 FR 17028, May 8, 1986]

§73.295   FM subsidiary communications services.

(a) Subsidiary communication services are those transmitted on a subcarrier within the FM baseband signal, but do not include services which enhance the main program broadcast service, or exclusively relate to station operations (see §73.293). Subsidiary communications include, but are not limited to services such as functional music, specialized foreign language programs, radio reading services, utility load management, market and financial data and news, paging and calling, traffic control signal switching, bilingual television audio, and point to point or multipoint messages.

(b) FM subsidiary communications services that are common carrier in nature are subject to common carrier regulation. Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service. Responsibility for making the initial determinations of whether a particular activity is common carriage rests with the FM station licensee. Initial determinations by licensees are subject to FCC examination and may be reviewed at the FCC's discretion.

(c) Subsidiary communications services are of a secondary nature under the authority of the FM station authorization, and the authority to provide such communications services may not be retained or transferred in any manner separate from the station's authorization. The grant or renewal of an FM station permit or license is not furthered or promoted by proposed or past services. The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided.

(d) The station identification, delayed recording and sponsor identification announcements required by §§73.1201, 73.1208, and 73.1212 are not applicable to material transmitted under an SCA.

(e) The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable.

[48 FR 28454, June 22, 1983, as amended at 48 FR 44805, Sept. 30, 1983; 49 FR 33663, Aug. 15, 1984; 50 FR 32416, Aug. 12, 1985; 57 FR 48333, Oct. 23, 1992]

§73.297   FM stereophonic sound broadcasting.

(a) An FM broadcast station may, without specific authority from the FCC, transmit stereophonic (biphonic, quadraphonic, etc.) sound programs upon installation of stereophonic sound transmitting equipment under the provisions of §§2.1001, 73.322, and 73.1590 of the Rules. Prior to commencement of stereophonic sound broadcasting, equipment performance measurements must be made to ensure that the transmitted signal complies with all applicable rules and standards.

(b) Each licensee or permittee engaging in multichannel broadcasting must measure the pilot subcarrier frequency as often as necessary to ensure that it is kept at all times within 2 Hz of the authorized frequency.

[48 FR 28454, June 22, 1983, and 48 FR 38479, Aug. 24, 1983]

§73.310   FM technical definitions.

(a) Frequency modulation. Antenna height above average terrain (HAAT). HAAT is calculated by: determining the average of the antenna heights above the terrain from 3 to 16 kilometers (2 to 10 miles) from the antenna for the eight directions evenly spaced for each 45° of azimuth starting with True North (a different antenna height will be determined in each direction from the antenna): and computing the average of these separate heights. In some cases less than eight directions may be used. (See §73.313(d).) Where circular or elliptical polarization is used, the antenna height above average terrain must be based upon the height of the radiation of the antenna that transmits the horizontal component of radiation.

Antenna power gain. The square of the ratio of the root-mean-square (RMS) free space field strength produced at 1 kilometer in the horizontal plane in millivolts per meter for 1 kW antenna input power to 221.4 mV/m. This ratio is expressed in decibels (dB). If specified for a particular direction, antenna power gain is based on that field strength in the direction only.

Auxiliary facility. An auxiliary facility is an antenna separate from the main facility's antenna, permanently installed on the same tower or at a different location, from which a station may broadcast for short periods without prior Commission authorization or notice to the Commission while the main facility is not in operation (e.g., where tower work necessitates turning off the main antenna or where lightning has caused damage to the main antenna or transmission system) (See §73.1675).

Center frequency. The term “center frequency” means:

(1) The average frequency of the emitted wave when modulated by a sinusoidal signal.

(2) The frequency of the emitted wave without modulation.

Composite antenna pattern. The composite antenna pattern is a relative field horizontal plane pattern for 360 degrees of azimuth, for which the value at a particular azimuth is the greater of the horizontally polarized or vertically polarized component relative field values. The composite antenna pattern is normalized to a maximum of unity (1.000) relative field.

Composite baseband signal. A signal which is composed of all program and other communications signals that frequency modulates the FM carrier.

Effective radiated power. The term “effective radiated power” means the product of the antenna power (transmitter output power less transmission line loss) times: (1) The antenna power gain, or (2) the antenna field gain squared. Where circular or elliptical polarization is employed, the term effective radiated power is applied separately to the horizontal and vertical components of radiation. For allocation purposes, the effective radiated power authorized is the horizontally polarized component of radiation only.

Equivalent isotropically radiated power (EIRP). The term “equivalent isotropically radiated power (also known as “effective radiated power above isotropic) means the product of the antenna input power and the antenna gain in a given direction relative to an isotropic antenna.

FM Blanketing. Blanketing is that form of interference to the reception of other broadcast stations which is caused by the presence of an FM broadcast signal of 115 dBu (562 mV/m) or greater signal strength in the area adjacent to the antenna of the transmitting station. The 115 dBu contour is referred to as the blanketing contour and the area within this contour is referred to as the blanketing area.

FM broadcast band. The band of frequencies extending from 88 to 108 MHz, which includes those assigned to noncommercial educational broadcasting.

FM broadcast channel. A band of frequencies 200 kHz wide and designated by its center frequency. Channels for FM broadcast stations begin at 88.1 MHz and continue in successive steps of 200 kHz to and including 107.9 MHz.

FM broadcast station. A station employing frequency modulation in the FM broadcast band and licensed primarily for the transmission of radiotelephone emissions intended to be received by the general public.

Field strength. The electric field strength in the horizontal plane.

Free space field strength. The field strength that would exist at a point in the absence of waves reflected from the earth or other reflecting objects.

Frequency departure. The amount of variation of a carrier frequency or center frequency from its assigned value.

Frequency deviation. The peak difference between modulated wave and the carrier frequency.

Frequency modulation. A system of modulation where the instantaneous radio frequency varies in proportion to the instantaneous amplitude of the modulating signal (amplitude of modulating signal to be measured after pre-emphasis, if used) and the instantaneous radio frequency is independent of the frequency of the modulating signal.

Frequency swing. The peak difference between the maximum and the minimum values of the instantaneous frequency of the carrier wave during modulation.

Multiplex transmission. The term “multiplex transmission” means the simultaneous transmission of two or more signals within a single channel. Multiplex transmission as applied to FM broadcast stations means the transmission of facsimile or other signals in addition to the regular broadcast signals.

Percentage modulation. The ratio of the actual frequency deviation to the frequency deviation defined as 100% modulation, expressed in percentage. For FM broadcast stations, a frequency deviation of ±75kHz is defined as 100% modulation.

(b) Stereophonic sound broadcasting. Cross-talk. An undesired signal occurring in one channel caused by an electrical signal in another channel.

FM stereophonic broadcast. The transmission of a stereophonic program by a single FM broadcast station utilizing the main channel and a stereophonic subchannel.

Left (or right) signal. The electrical output of a microphone or combination of microphones placed so as to convey the intensity, time, and location of sounds originating predominately to the listener's left (or right) of the center of the performing area.

Left (or right) stereophonic channel. The left (or right) signal as electrically reproduced in reception of FM stereophonic broadcasts.

Main channel. The band of frequencies from 50 to 15,000 Hz which frequency-modulate the main carrier.

Pilot subcarrier. A subcarrier that serves as a control signal for use in the reception of FM stereophonic sound broadcasts.

Stereophonic separation. The ratio of the electrical signal caused in sound channel A to the signal caused in sound channel B by the transmission of only a channel B signal. Channels A and B may be any two channels of a stereophonic sound broadcast transmission system.

Stereophonic sound. The audio information carried by plurality of channels arranged to afford the listener a sense of the spatial distribution of sound sources. Stereophonic sound broadcasting includes, but is not limited to, biphonic (two channel), triphonic (three channel) and quadrophonic (four channel) program services.

Stereophonic sound subcarrier. A subcarrier within the FM broadcast baseband used for transmitting signals for stereophonic sound reception of the main broadcast program service.

Stereophonic sound subchannel. The band of frequencies from 23 kHz to 99 kHz containing sound subcarriers and their associated sidebands.

(c) Visual transmissions. Communications or message transmitted on a subcarrier intended for reception and visual presentation on a viewing screen, teleprinter, facsimile printer, or other form of graphic display or record.

(d) Control and telemetry transmissions. Signals transmitted on a multiplex subcarrier intended for any form of control and switching functions or for equipment status data and aural or visual alarms.

[28 FR 13623, Dec. 14, 1963, as amended at 39 FR 10575, Mar. 21, 1974; 44 FR 36038, June 20, 1979; 48 FR 28454, June 22, 1983; 48 FR 29507, June 27, 1983; 48 FR 37216, Aug. 17, 1983; 49 FR 45145, Nov. 15, 1984; 57 FR 48333, Oct. 23, 1992; 62 FR 51058, Sept. 30, 1997]

§73.311   Field strength contours.

(a) Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 301 or FCC Form 340, as appropriate.

(b) The field strength contours provided for in this section shall be considered for the following purposes only:

(1) In the estimation of coverage resulting from the selection of a particular transmitter site by an applicant for an FM broadcast station.

(2) In connection with problems of coverage arising out of application of §73.3555.

(3) In determining compliance with §73.315(a) concerning the minimum field strength to be provided over the principal community to be served.

(4) In determining compliance with §73.215 concerning contour protection.

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 32 FR 11471, Aug. 9, 1967; 52 FR 10570, Apr. 2, 1987; 54 FR 9802, Mar. 8, 1989]

§73.312   Topographic data.

(a) In the preparation of the profile graphs previously described, and in determining the location and height above mean sea level of the antenna site, the elevation or contour intervals shall be taken from United States Geological Survey Topographic Quadrangle Maps, United States Army Corps of Engineers Maps or Tennessee Valley Authority maps, whichever is the latest, for all areas for which such maps are available. If such maps are not published for the area in question, the next best topographic information should be used. Topographic data may sometimes be obtained from state and municipal agencies. The data from the Sectional Aeronautical Charts (including bench marks) or railroad depot elevations and highway elevations from road maps may be used where no better information is available. In cases where limited topographic data can be obtained, use may be made of an altimeter in a car driven along roads extending generally radially from the transmitter site.

(b) The Commission will not ordinarily require the submission of topographical maps for areas beyond 24 km (15 miles) from the antenna site, but the maps must include the principal city or cities to be served. If it appears necessary, additional data may be requested.

(c) The U.S. Geological Survey Topography Quadrangle Sheets may be obtained from the U.S. Geological Survey Department of the Interior, Washington, DC 20240. The Sectional Aeronautical Charts are available from the U.S. Coast and Geodetic Survey, Department of Commerce, Washington, DC 20235. These maps may also be secured from branch offices and from authorized agents or dealers in most principal cities.

(d) In lieu of maps, the average terrain elevation may be computer generated except in cases of dispute, using elevations from a 30 second, point or better topographic data file. The file must be identified and the data processed for intermediate points along each radial using linear interpolation techniques. The height above mean sea level of the antenna site must be obtained manually using appropriate topographic maps.

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 49 FR 48937, Dec. 17, 1984; 58 FR 44950, Aug. 25, 1993; 63 FR 33877, June 22, 1998]

§73.313   Prediction of coverage.

(a) All predictions of coverage made pursuant to this section shall be made without regard to interference and shall be made only on the basis of estimated field strengths.

(b) Predictions of coverage shall be made only for the same purposes as relate to the use of field strength contours as specified in §73.311.

(c) In predicting the distance to the field strength contours, the F(50,50) field strength chart, Figure 1 of §73.333 must be used. The 50% field strength is defined as that value exceeded for 50% of the time.

(1) The F(50,50) chart gives the estimated 50% field strengths exceeded at 50% of the locations in dB above 1 uV/m. The chart is based on an effective power radiated from a half-wave dipole antenna in free space, that produces an unattenuated field strength at 1 kilometer of about 107 dB above 1 uV/m (221.4 mV/m).

(2) To use the chart for other ERP values, convert the ordinate scale by the appropriate adjustment in dB. For example, the ordinate scale for an ERP of 50 kW should be adjusted by 17 dB [10 log (50 kW) = 17 dBk], and therefore a field strength of 60 dBu would correspond to the field strength value at (60−17 =) 44 dBu on the chart. When predicting the distance to field strength contours, use the maximum ERP of the main radiated lobe in the pertinent azimuthal direction (do not account for beam tilt). When predicting field strengths over areas not in the plane of the maximum main lobe, use the ERP in the direction of such areas, determined by considering the appropriate vertical radiation pattern.

(d) The antenna height to be used with this chart is the height of the radiation center of the antenna above the average terrain along the radial in question. In determining the average elevation of the terrain, the elevations between 3 and 16 kilometers from the antenna site are used.

(1) Profile graphs must be drawn for eight radials beginning at the antenna site and extending 16 kilometers therefrom. The radials should be drawn for each 45° of azimuth starting with True North. At least one radial must include the principal community to be served even though it may be more than 16 kilometers from the antenna site. However, in the event none of the evenly spaced radials include the principal community to be served, and one or more such radials are drawn in addition, these radials must not be used in computing the antenna height above average terrain.

(2) Where the 3 to 16 kilometers portion of a radial extends in whole or in part over a large body of water or extends over foreign territory but the 50 uV/m (34 dBu) contour encompasses land area within the United States beyond the 16 kilometers portion of the radial, the entire 3 to 16 kilometers portion of the radial must be included in the computation of antenna height above average terrain. However, where the 50 uV/m (34 dBu) contour does not so encompass United States land area, and (i) the entire 3 to 16 kilometers portion of the radial extends over large bodies of water or over foreign territory, such radial must be completely omitted from the computation of antenna height above average terrain, and (ii) where a part of the 3 to 16 kilometers portion of a radial extends over large bodies of water or foreign territory, only that part of the radial extending from 3 kilometers to the outermost portion of land in the United States covered by the radial used must be used in the computation of antenna height above average terrain.

(3) The profile graph for each radial should be plotted by contour intervals of from 12 to 30 meters and, where the data permits, at least 50 points of elevation (generally uniformly spaced) should be used for each radial. In instances of very rugged terrain where the use of contour intervals of 30 meters would result in several points in a short distance, 60 or 120 meter contour intervals may be used for such distances. On the other hand, where the terrain is uniform or gently sloping the smallest contour interval indicated on the topographic map should be used, although only relatively few points may be available. The profile graph should indicate the topography accurately for each radial, and the graphs should be plotted with the distance in kilometers as the abscissa and the elevation in meters above mean sea level as the ordinate. The profile graphs should indicate the source of the topographical data used. The graph should also show the elevation of the center of the radiating system. The graph may be plotted either on rectangular coordinate paper or on special paper that shows the curvature of the earth. It is not necessary to take the curvature of the earth into consideration in this procedure as this factor is taken care of in the charts showing signal strengths. The average elevation of the 13 kilometer distance between 3 and 16 kilometers from the antenna site should then be determined from the profile graph for each radial. This may be obtained by averaging a large number of equally spaced points, by using a planimeter, or by obtaining the median elevation (that exceeded for 50% of the distance) in sectors and averaging those values.

(4) Examples of HAAT calculations:

(i) The heights above average terrain on the eight radials are as follows:

  Meters
120
45°255
90°185
135°90
180°−10
225°−85
270°40
315°85

The antenna height above terrain (defined in §73.310(a)) is computed as follows:

(120 + 255 + 185 + 90 − 10 − 85 + 40 + 85) / 8 = 85 meters.

(ii) Same as paragraph (d)(4)(i) of this section, except the 0° radial is entirely over sea water. The antenna height above average terrain is computed as follows (note that the divisor is 7 not 8):

(255 + 185 + 90 − 10 − 85 + 40 + 85) / 7 = 80 meters.

(iii) Same as paragraph (d)(4)(i) of this section, except that only the first 10 kilometers of the 90° radial are in the United States; beyond 10 kilometers the 90° radial is in a foreign country. The height above average terrain of the 3 to 10 kilometer portion of the 90° radial is 105 meters. The antenna height above average terrain is computed as follows (note that the divisor is 8 not 7.5):

(120 + 255 + 105 + 90 − 10 − 85 + 40 + 85) / 8 = 75 meters.

(e) In cases where the terrain in one or more directions from the antenna site departs widely from the average elevation of the 3 to 16 kilometer sector, the prediction method may indicate contour distances that are different from what may be expected in practice. For example, a mountain ridge may indicate the practical limit of service although the prediction method may indicate otherwise. In such cases, the prediction method should be followed, but a supplemental showing may be made concerning the contour distances as determined by other means. Such supplemental showings should describe the procedure used and should include sample calculations. Maps of predicted coverage should include both the coverage as predicted by the regular method and as predicted by a supplemental method. When measurements of area are required, these should include the area obtained by the regular prediction method and the area obtained by the supplemental method. In directions where the terrain is such that antenna heights less than 30 meters for the 3 to 16 kilometer sector are obtained, an assumed height of 30 meters must be used for the prediction of coverage. However, where the actual contour distances are critical factors, a supplemental showing of expected coverage must be included together with a description of the method used in predicting such coverage. In special cases, the FCC may require additional information as to terrain and coverage.

(f) The effect of terrain roughness on the predicted field strength of a signal at points distant from an FM transmitting antenna is assumed to depend on the magnitude of a terrain roughness factor (h) which, for a specific propagation path, is determined by the characteristics of a segment of the terrain profile for that path 40 kilometers in length located between 10 and 50 kilometers from the antenna. The terrain roughness factor has a value equal to the distance, in meters, between elevations exceeded by all points on the profile for 10% and 90% respectively, of the length of the profile segment. (See §73.333, Figure 4.)

(g) If the lowest field strength value of interest is initially predicted to occur over a particular propagation path at a distance that is less than 50 kilometers from the antenna, the terrain profile segment used in the determination of terrain roughness factor over that path must be that included between points 10 kilometers from the transmitter and such lesser distances. No terrain roughness correction need be applied when all field strength values of interest are predicted to occur 10 kilometers or less from the transmitting antenna.

(h) Profile segments prepared for terrain roughness factor determinations are to be plotted in rectangular coordinates, with no less than 50 points evenly spaced within the segment using data obtained from topographic maps with contour intervals of approximately 15 meters (50 feet) or less if available.

(i) The field strength charts (§73.333, Figs. 1-1a) were developed assuming a terrain roughness factor of 50 meters, which is considered to be representative of average terrain in the United States. Where the roughness factor for a particular propagation path is found to depart appreciably from this value, a terrain roughness correction (ΔF) should be applied to field strength values along this path, as predicted with the use of these charts. The magnitude and sign of this correction, for any value of Δh, may be determined from a chart included in §73.333 as Figure 5.

(j) Alternatively, the terrain roughness correction may be computed using the following formula:

ΔF=1.9−0.03(Δh)(1+f/300)

Where:

ΔF=terrain roughness correction in dB

Δk=terrain roughness factor in meters

f=frequency of signal in MHz (MHz)

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13623, Dec. 14, 1963, as amended at 40 FR 27678, July 1, 1975; 48 FR 29507, June 27, 1983; 52 FR 11655, Apr. 10, 1987; 52 FR 37789, Oct. 9, 1987; 57 FR 48333, Oct. 23, 1992; 63 FR 33877, June 22, 1998]

Effective Date Note: At 42 FR 25736, May 19, 1977, the effective date of §73.313 paragraphs (i) and (j) was stayed indefinitely.

§73.314   Field strength measurements.

(a) Except as provided for in §73.209, FM broadcast stations shall not be protected from any type of interference or propagation effect. Persons desiring to submit testimony, evidence or data to the Commission for the purpose of showing that the technical standards contained in this subpart do not properly reflect the levels of any given type of interference or propagation effect may do so only in appropriate rule making proceedings concerning the amendment of such technical standards. Persons making field strength measurements for formal submission to the Commission in rule making proceedings, or making such measurements upon the request of the Commission, shall follow the procedure for making and reporting such measurements outlined in paragraph (b) of this section. In instances where a showing of the measured level of a signal prevailing over a specific community is appropriate, the procedure for making and reporting field strength measurements for this purpose is set forth in paragraph (c) of this section.

(b) Collection of field strength data for propagation analysis.

(1) Preparation for measurements. (i) On large scale topographic maps, eight or more radials are drawn from the transmitter location to the maximum distance at which measurements are to be made, with the angles included between adjacent radials of approximately equal size. Radials should be oriented so as to traverse representative types of terrain. The specific number of radials and their orientation should be such as to accomplish this objective.

(ii) Each radial is marked, at a point exactly 16 kilometers from the transmitter and, at greater distances, at successive 3 kilometer intervals. Where measurements are to be conducted over extremely rugged terrain, shorter intervals may be used, but all such intervals must be of equal length. Accessible roads intersecting each radial as nearly as possible at each 3 kilometer marker are selected. These intersections are the points on the radial at which measurements are to be made, and are referred to subsequently as measuring locations. The elevation of each measuring location should approach the elevation at the corresponding 3 kilometer marker as nearly as possible.

(2) Measurement procedure. All measurements must be made utilizing a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9 meters above the roadbed. At each measuring location, the following procedure must be used:

(i) The instrument calibration is checked.

(ii) The antenna is elevated to a height of 9 meters.

(iii) The receiving antenna is rotated to determine if the strongest signal is arriving from the direction of the transmitter.

(iv) The antenna is oriented so that the sector of its response pattern over which maximum gain is realized is in the direction of the transmitter.

(v) A mobile run of at least 30 meters is made, that is centered on the intersection of the radial and the road, and the measured field strength is continuously recorded on a chart recorder over the length of the run.

(vi) The actual measuring location is marked exactly on the topographic map, and a written record, keyed to the specific location, is made of all factors which may affect the recorded field, such as topography, height and types of vegetation, buildings, obstacles, weather, and other local features.

(vii) If, during the test conducted as described in paragraph (b)(2)(iii) of this section, the strongest signal is found to come from a direction other than from the transmitter, after the mobile run prescribed in paragraph (b)(2)(v) of this section is concluded, additional measurements must be made in a “cluster” of at least five fixed points. At each such point, the field strengths with the antenna oriented toward the transmitter, and with the antenna oriented so as to receive the strongest field, are measured and recorded. Generally, all points should be within 60 meters of the center point of the mobile run.

(viii) If overhead obstacles preclude a mobile run of at least 30 meters, a “cluster” of five spot measurements may be made in lieu of this run. The first measurement in the cluster is identified. Generally, the locations for other measurements must be within 60 meters of the location of the first.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) Tables of field strength measurements, which, for each measuring location, set forth the following data:

(A) Distance from the transmitting antenna.

(B) Ground elevation at measuring location.

(C) Date, time of day, and weather.

(D) Median field in dBu for 0 dBk, for mobile run or for cluster, as well as maximum and minimum measured field strengths.

(E) Notes describing each measuring location.

(ii) U.S. Geological Survey topographic maps, on which is shown the exact location at which each measurement was made. The original plots shall be made on maps of the largest available scale. Copies may be reduced in size for convenient submission to the Commission, but not to the extent that important detail is lost. The original maps shall be made available, if requested. If a large number of maps is involved, an index map should be submitted.

(iii) All information necessary to determine the pertinent characteristics of the transmitting installation, including frequency, geographical coordinates of antenna site, rated and actual power output of transmitter, measured transmission line loss, antenna power gain, height of antenna above ground, above mean sea level, and above average terrain. The effective radiated power should be computed, and horizontal and vertical plane patterns of the transmitting antenna should be submitted.

(iv) A list of calibrated equipment used in the field strength survey, which, for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(v) A detailed description of the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

(vi) Terrain profiles in each direction in which measurements were made, drawn on curved earth paper for equivalent 4/3 earth radius, of the largest available scale.

(c) Collection of field strength data to determine FM broadcast service in specific communities.

(1) Preparation for measurement. (i) The population (P) of the community, and its suburbs, if any, is determined by reference to an appropriate source, e.g., the 1970 U.S. Census tables of population of cities and urbanized areas.

(ii) The number of locations at which measurements are to be made shall be at least 15, and shall be approximately equal to 0.1(P)1/2, if this product is a number greater than 15.

(iii) A rectangular grid, of such size and shape as to encompass the boundaries of the community is drawn on an accurate map of the community. The number of line intersections on the grid included within the boundaries of the community shall be at least equal to the required number of measuring locations. The position of each intersection on the community map determines the location at which a measurement shall be made.

(2) Measurement procedure. All measurements must be made using a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9 meters above ground level.

(i) Each measuring location shall be chosen as close as feasible to a point indicated on the map, as previously prepared, and at as nearly the same elevation as that point as possible.

(ii) At each measuring location, after equipment calibration and elevation of the antenna, a check is made to determine whether the strongest signal arrives from a direction other than from the transmitter.

(iii) At 20 percent or more of the measuring locations, mobile runs, as described in paragraph (b)(2) of this section shall be made, with no less than three such mobile runs in any case. The points at which mobile measurements are made shall be well separated. Spot measurements may be made at other measuring points.

(iv) Each actual measuring location is marked exactly on the map of the community, and suitably keyed. A written record shall be maintained, describing, for each location, factors which may affect the recorded field, such as the approximate time of measurement, weather, topography, overhead wiring, heights and types of vegetation, buildings and other structures. The orientation, with respect to the measuring location shall be indicated of objects of such shape and size as to be capable of causing shadows or reflections. If the strongest signal received was found to arrive from a direction other than that of the transmitter, this fact shall be recorded.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) A map of the community showing each actual measuring location, specifically identifying the points at which mobile runs were made.

(ii) A table keyed to the above map, showing the field strength at each measuring point, reduced to dBu for the actual effective radiated power of the station. Weather, date, and time of each measurement shall be indicated.

(iii) Notes describing each measuring location.

(iv) A topographic map of the largest available scale on which are marked the community and the transmitter site of the station whose signals have been measured, which includes all areas on or near the direct path of signal propagation.

(v) Computations of the mean and standard deviation of all measured field strengths, or a graph on which the distribution of measured field strength values is plotted.

(vi) A list of calibrated equipment used for the measurements, which for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(vii) A detailed description of the procedure employed in the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

[40 FR 27682, July 1, 1975; 40 FR 28802, July 9, 1975, as amended at 48 FR 29508, June 27, 1983]

§73.315   FM transmitter location.

(a) The transmitter location shall be chosen so that, on the basis of the effective radiated power and antenna height above average terrain employed, a minimum field strength of 70 dB above one uV/m (dBu), or 3.16 mV/m, will be provided over the entire principal community to be served.

(b) The transmitter location should be chosen to maximize coverage to the city of license while minimizing interference. This is normally accomplished by locating in the least populated area available while maintaining the provisions of paragraph (a) of this section. In general, the transmitting antenna of a station should be located in the most sparsely populated area available at the highest elevation available. The location of the antenna should be so chosen that line-of-sight can be obtained from the antenna over the principle city or cities to be served; in no event should there be a major obstruction in this path.

(c) The transmitting location should be selected so that the 1 mV/m contour encompasses the urban population within the area to be served. It is recognized that topography, shape of the desired service area, and population distribution may make the choice of a transmitter location difficult. In such cases consideration may be given to the use of a directional antenna system, although it is generally preferable to choose a site where a nondirectional antenna may be employed.

(d) In cases of questionable antenna locations it is desirable to conduct propagation tests to indicate the field strength expected in the principal city or cities to be served and in other areas, particularly where severe shadow problems may be expected. In considering applications proposing the use of such locations, the Commission may require site tests to be made. Such tests should include measurements made in accordance with the measurement procedures described in §73.314, and full data thereon shall be supplied to the Commission. The test transmitter should employ an antenna having a height as close as possible to the proposed antenna height, using a balloon or other support if necessary and feasible. Information concerning the authorization of site tests may be obtained from the Commission upon request.

(e) Cognizance must of course be taken regarding the possible hazard of the proposed antenna structure to aviation and the proximity of the proposed site to airports and airways. Procedures and standards with respect to the Commission's consideration of proposed antenna structures which will serve as a guide to persons intending to apply for radio station licenses are contained in Part 17 of this chapter (Construction, Marking, and Lighting of Antenna Structures).

[28 FR 13623, Dec. 14, 1963, as amended at 41 FR 22943, June 8, 1976; 49 FR 38131, Sept. 27, 1984; 49 FR 45146, Nov. 15, 1984; 51 FR 9965, Mar. 24, 1986; 52 FR 10570, Apr. 2, 1987; 65 FR 79778, Dec. 20, 2000]

§73.316   FM antenna systems.

(a) It shall be standard to employ horizontal polarization; however, circular or elliptical polarization may be employed if desired. Clockwise or counterclockwise rotation may be used. The supplemental vertically polarized effective radiated power required for circular or elliptical polarization shall in no event exceed the effective radiated power authorized.

(b) Directional antennas. A directional antenna is an antenna that is designed or altered for the purpose of obtaining a non-circular radiation pattern.

(1) Applications for the use of directional antennas that propose a ratio of maximum to minimum radiation in the horizontal plane of more than 15 dB will not be accepted.

(2) Directional antennas used to protect short-spaced stations pursuant to §73.213 or §73.215 of the rules, that have a radiation pattern which varies more than 2 dB per 10 degrees of azimuth will not be authorized.

(c) Applications for directional antennas. (1) Applications for construction permit proposing the use of directional antenna systems must include a tabulation of the composite antenna pattern for the proposed directional antenna. A value of 1.0 must be used to correspond to the direction of maximum radiation. The pattern must be tabulated such that 0° corresponds to the direction of maximum radiation or alternatively, in the case of an asymmetrical antenna pattern, the pattern must be tabulated such that 0° corresponds to the actual azimuth with respect to true North. In the case of a composite antenna composed of two or more individual antennas, the pattern required is that for the composite antenna, not the patterns for each of the individual antennas. Applications must include valuations tabulated at intervals of not greater than ten (10) degrees. In addition, tabulated values of all maximas and minimas, with their corresponding azimuths, must be submitted.

(2) Applications for license upon completion of antenna construction must include the following:

(i) A complete description of the antenna system, including the manufacturer and model number of the directional antenna. It is not sufficient to label the antenna with only a generic term such as “dipole.” In the case of individually designed antennas with no model number, or in the case of a composite antenna composed of two or more individual antennas, the antenna must be described as a “custom” or “composite” antenna, as appropriate. A full description of the design of the antenna must also be submitted.

(ii) A plot of the composite pattern of the directional antenna. A value of 1.0 must be used to correspond to the direction of maximum radiation. The plot of the pattern must be oriented such that 0° corresponds to the direction of maximum radiation or alternatively, in the case of an asymmetrical antenna pattern, the plot must be oriented such that 0° corresponds to the actual azimuth with respect to true North. The horizontal plane pattern must be plotted to the largest scale possible on unglazed letter-size polar coordinate paper (main engraving approximately 18 cm × 25 cm (7 inches × 10 inches)) using only scale divisions and subdivisions of 1, 2, 2.5, or 5 times 10-nth. Values of field strength less than 10% of the maximum field strength plotted on that pattern must be shown on an enlarged scale. In the case of a composite antenna composed of two or more individual antennas, the composite antenna pattern should be provided, and not the pattern for each of the individual antennas.

(iii) A tabulation of the measured relative field pattern required in paragraph (c)(1) of this section. The tabulation must use the same zero degree reference as the plotted pattern, and must contain values for at least every 10 degrees. Sufficient vertical patterns to indicate clearly the radiation characteristics of the antenna above and below the horizontal plane. Complete information and patterns must be provided for angles of −10 deg. from the horizontal plane and sufficient additional information must be included on that portion of the pattern lying between +10 deg. and the zenith and −10 deg. and the nadir, to conclusively demonstrate the absence of undesirable lobes in these areas. The vertical plane pattern must be plotted on rectangular coordinate paper with reference to the horizontal plane. In the case of a composite antenna composed of two or more individual antennas, the composite antenna pattern should be used, and not the pattern for each of the individual antennas.

(iv) A statement that the antenna is mounted on the top of an antenna tower recommended by the antenna manufacturer, or is side-mounted on a particular type of antenna tower in accordance with specific instructions provided by the antenna manufacturer.

(v) A statement that the directional antenna is not mounted on the top of an antenna tower which includes a top-mounted platform larger than the nominal cross-sectional area of the tower in the horizontal plane.

(vi) A statement that no other antenna of any type is mounted on the same tower level as a directional antenna, and that no antenna of any type is mounted within any horizontal or vertical distance specified by the antenna manufacturer as being necessary for proper directional operation.

(vii) A statement from an engineer listing such individual engineer's qualifications and certifying that the antenna has been installed pursuant to the manufacturer's instructions.

(viii) A statement from a licensed surveyor that the installed antenna is properly oriented.

(ix)(A) For a station authorized pursuant to §73.215 or Sec. §73.509, a showing that the root mean square (RMS) of the measured composite antenna pattern (encompassing both the horizontally and vertically polarized radiation components (in relative field)) is at least 85 percent of the RMS of the authorized composite directional antenna pattern (in relative field). The RMS value, for a composite antenna pattern specified in relative field values, may be determined from the following formula:

RMS=the square root of:

[(relative field value 1)2 + (relative field value 2)2 +....+ (last relative field value)2]

total number of relative field values

(B) where the relative field values are taken from at least 36 evenly spaced radials for the entire 360 degrees of azimuth. The application for license must also demonstrate that coverage of the community of license by the 70 dBu contour is maintained for stations authorized pursuant to §73.215 on Channels 221 through 300, as required by §73.315(a), while noncommercial educational stations operating on Channels 201 through 220 must show that the 60 dBu contour covers at least a portion of the community of license.

(d) Applications proposing the use of FM transmitting antennas in the immediate vicinity (i.e. 60 meters or less) of other FM or TV broadcast antennas must include a showing as to the expected effect, if any, of such approximate operation.

(e) Where an FM licensee or permittee proposes to mount its antenna on or near an AM tower, as defined in §1.30002, the FM licensee or permittee must comply with §1.30003 or §1.30002, depending on whether the antenna is proposed to be mounted on an AM tower (§1.30003) or near an AM tower (§1.30002).

[28 FR 13623, Dec. 14, 1963, as amended at 34 FR 14222, Sept. 10, 1969; 37 FR 25841, Dec. 5, 1972; 43 FR 53738, Nov. 17, 1978; 48 FR 29508, June 27, 1983; 51 FR 17028, May 8, 1986; 54 FR 9804, Mar. 8, 1989; 56 FR 57294, Nov. 8, 1991; 62 FR 51058, Sept. 30, 1997; 63 FR 70047, Dec. 18, 1998; 78 FR 66298, Nov. 5, 2013]

§73.317   FM transmission system requirements.

(a) FM broadcast stations employing transmitters authorized after January 1, 1960, must maintain the bandwidth occupied by their emissions in accordance with the specification detailed below. FM broadcast stations employing transmitters installed or type accepted before January 1, 1960, must achieve the highest degree of compliance with these specifications practicable with their existing equipment. In either case, should harmful interference to other authorized stations occur, the licensee shall correct the problem promptly or cease operation.

(b) Any emission appearing on a frequency removed from the carrier by between 120 kHz and 240 kHz inclusive must be attenuated at least 25 dB below the level of the unmodulated carrier. Compliance with this requirement will be deemed to show the occupied bandwidth to be 240 kHz or less.

(c) Any emission appearing on a frequency removed from the carrier by more than 240 kHz and up to and including 600 kHz must be attenuated at least 35 dB below the level of the unmodulated carrier.

(d) Any emission appearing on a frequency removed from the carrier by more than 600 kHz must be attenuated at least 43 + 10 Log10 (Power, in watts) dB below the level of the unmodulated carrier, or 80 dB, whichever is the lesser attenuation.

(e) Preemphasis shall not be greater than the impedance-frequency characteristics of a series inductance resistance network having a time constant of 75 microseconds. (See upper curve of Figure 2 of §73.333.)

[51 FR 17028, May 8, 1986]

§73.318   FM blanketing interference.

Areas adjacent to the transmitting antenna that receive a signal with a strength of 115 dBu (562 mV/m) or greater will be assumed to be blanketed. In determining the blanketed area, the 115 dBu contour is determined by calculating the inverse distance field using the effective radiated power of the maximum radiated lobe of the antenna without considering its vertical radiation pattern or height. For directional antennas, the effective radiated power in the pertinent bearing shall be used.

(a) The distance to the 115 dBu contour is determined using the following equation:

D (in kilometers)=0.394√ P

D (in miles)=0.245√ P

Where P is the maximum effective radiated power (ERP), measured in kilowatts, of the maximum radiated lobe.

(b) After January 1, 1985, permittees or licensees who either (1) commence program tests, or (2) replace their antennas, or (3) request facilities modifications and are issued a new construction permit must satisfy all complaints of blanketing interference which are received by the station during a one year period. The period begins with the commencement of program tests, or commencement of programming utilizing the new antenna. Resolution of complaints shall be at no cost to the complainant. These requirements specifically do not include interference complaints resulting from malfunctioning or mistuned receivers, improperly installed antenna systems, or the use of high gain antennas or antenna booster amplifiers. Mobile receivers and non-RF devices such as tape recorders or hi-fi amplifiers (phonographs) are also excluded.

(c) A permittee collocating with one or more existing stations and beginning program tests on or after January 1, 1985, must assume full financial responsibility for remedying new complaints of blanketing interference for a period of one year. Two or more permittees that concurrently collocate on or after January 1, 1985, shall assume shared responsibility for remedying blanketing complaints within the blanketing area unless an offending station can be readily determined and then that station shall assume full financial responsibility.

(d) Following the one year period of full financial obligation to satisfy blanketing complaints, licensees shall provide technical information or assistance to complainants on remedies for blanketing interference.

[28 FR 13623, Dec. 14, 1963, as amended at 52 FR 25866, July 9, 1987]

§73.319   FM multiplex subcarrier technical standards.

(a) The technical specifications in this Section apply to all transmissions of FM multiplex subcarriers except those used for stereophonic sound broadcasts under the provisions of §73.322.

(b) Modulation. Any form of modulation may be used for subcarrier operation.

(c) Subcarrier baseband. (1) During monophonic program transmissions, multiplex subcarriers and their significant sidebands must be within the range of 20 kHz to 99 kHz.

(2) During stereophonic sound program transmissions (see §73.322), multiplex subcarriers and their significant sidebands must be within the range of 53 kHz to 99 kHz.

(3) During periods when broadcast programs are not being transmitted, multiplex subcarriers and their significant sidebands must be within the range of 20 kHz to 99 kHz.

(d) Subcarrier injection. (1) During monophonic program transmissions, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 30% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(2) During stereophonic program transmissions, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 20% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(3) During periods when no broadcast program service is transmitted, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 30% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(4) Total modulation of the carrier wave during transmission of multiplex subcarriers used for subsidiary communications services must comply with the provisions §73.1570(b).

(e) Subcarrier generators may be installed and used with a type accepted FM broadcast transmitter without specific authorization from the FCC provided the generator can be connected to the transmitter without requiring any mechanical or electrical modifications in the transmitter FM exciter circuits.

(f) Stations installing multiplex subcarrier transmitting equipment must ensure the proper suppression of spurious or harmonic radiations. See §§73.317, 73.1590 and 73.1690. If the subcarrier operation causes the station's transmissions not to comply with the technical provisions for FM broadcast stations or causes harmful interference to other communication services, the licensee or permittee must correct the problem promptly or cease operation. The licensee may be required to verify the corrective measures with supporting data. Such data must be retained at the station and be made available to the FCC upon request.

[48 FR 28455, June 22, 1983, as amended at 48 FR 37216, Aug. 17, 1983; 49 FR 15080, Apr. 17, 1984; 49 FR 38131, Sept. 27, 1984; 50 FR 1534, Jan. 11, 1985; 51 FR 17029, May 8, 1986; 57 FR 48333, Oct. 23, 1992]

§73.322   FM stereophonic sound transmission standards.

(a) An FM broadcast station shall not use 19 kHz ±20 Hz, except as the stereophonic pilot frequency in a transmission system meeting the following parameters:

(1) The modulating signal for the main channel consists of the sum of the right and left signals.

(2) The pilot subcarrier at 19 kHz ±2 Hz, must frequency modulate the main carrier between the limits of 8 and 10 percent.

(3) One stereophonic subcarrier must be the second harmonic of the pilot subcarrier (i.e., 38 kHz) and must cross the time axis with a positive slope simultaneously with each crossing of the time axis by the pilot subcarrier. Additional stereophomic subcarriers are not precluded.

(4) Double sideband, suppressed-carrier, amplitude modulation of the stereophonic subcarrier at 38 kHz must be used.

(5) The stereophonic subcarrier at 38 kHz must be suppressed to a level less than 1% modulation of the main carrier.

(6) The modulating signal for the required stereophonic subcarrier must be equal to the difference of the left and right signals.

(7) The following modulation levels apply:

(i) When a signal exists in only one channel of a two channel (biphonic) sound transmission, modulation of the carrier by audio components within the baseband range of 50 Hz to 15 kHz shall not exceed 45% and modulation of the carrier by the sum of the amplitude modulated subcarrier in the baseband range of 23 kHz to 53 kHz shall not exceed 45%.

(ii) When a signal exists in only one channel of a stereophonic sound transmission having more than one stereophonic subcarrier in the baseband, the modulation of the carrier by audio components within the audio baseband range of 23 kHz to 99 kHz shall not exceed 53% with total modulation not to exceed 90%.

(b) Stations not transmitting stereo with the method described in (a), must limit the main carrier deviation caused by any modulating signals occupying the band 19 kHz ±20 Hz to 125 Hz.

(c) All stations, regardless of the stereophonic transmission system used, must not exceed the maximum modulation limits specified in §73.1570(b)(2). Stations not using the method described in (a), must limit the modulation of the carrier by audio components within the audio baseband range of 23 kHz to 99 kHz to not exceed 53%.

[51 FR 17029, May 8, 1986]

§73.333   Engineering charts.

This section consists of the following Figures 1, 1a, 2, and slider 4 and 5.

Note: The figures reproduced herein, due to their small scale, are not to be used in connection with material submitted to the F.C.C.

eCFR graphic ec01mr91.085.gif

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eCFR graphic ec01mr91.086.gif

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eCFR graphic ec01mr91.087.gif

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eCFR graphic ec01mr91.088.gif

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eCFR graphic ec01mr91.089.gif

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eCFR graphic ec01mr91.090.gif

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(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13623, Dec. 14, 1963, as amended at 35 FR 2591, Feb. 5, 1970; 40 FR 27679, July 1, 1975; 45 FR 28141, Apr. 28, 1980; 48 FR 29508, June 27, 1983; 49 FR 19670, May 9, 1984]

Effective Date Note: At 42 FR 25736, May 19, 1977, in §73.333, the effective date of Figures 4 and 5 was stayed indefinitely.

Subpart C—Digital Audio Broadcasting

Source: 72 FR 45692, Aug. 15, 2007, unless otherwise noted.

§73.401   Scope.

This subpart contains those rules which apply exclusively to the digital audio broadcasting (DAB) service, and are in addition to those rules in Subparts A, B, C, G and H which apply to AM and FM broadcast services, both commercial and noncommercial.

§73.402   Definitions.

(a) DAB. Digital audio broadcast stations are those radio stations licensed by the Commission and use the In-band On-channel (“IBOC”) system for broadcasting purposes.

(b) In Band On Channel DAB System. A technical system in which a station's digital signal is broadcast in the same spectrum and on the same channel as its analog signal.

(c) Hybrid DAB System. A system which transmits both the digital and analog signals within the spectral emission mask of a single AM or FM channel.

(d) Extended hybrid operation. An enhanced mode of FM IBOC DAB operation which includes additional DAB subcarriers transmitted between the analog FM signal and the inner edges of the primary DAB sidebands.

(e) Primary AM DAB Sidebands. The two groups of hybrid AM IBOC DAB subcarriers which are transmitted 10 to 15 kHz above carrier frequency (the upper primary DAB sideband), and 10 to 15 kHz below carrier frequency (the lower primary DAB sideband).

(f) Multicasting. Subdividing the digital bitstream into multiple channels for additional audio programming uses.

(g) Datacasting. Subdividing the digital bitstream into multiple channels for additional data or information services uses.

§73.403   Digital audio broadcasting service requirements.

(a) Broadcast radio stations using IBOC must transmit at least one over-the-air digital audio programming stream at no direct charge to listeners. In addition, a broadcast radio station must simulcast its analog audio programming on one of its digital audio programming streams. The DAB audio programming stream that is provided pursuant to this paragraph must be at least comparable in sound quality to the analog programming service currently provided to listeners.

(b) Emergency information. The emergency information requirements found in §73.1250 shall apply to all free DAB programming streams.

§73.404   Interim hybrid IBOC DAB operation.

(a) The licensee of an AM or FM station, or the permittee of a new AM or FM station which has commenced program test operation pursuant to §73.1620, may commence interim hybrid IBOC DAB operation with digital facilities which conform to the technical specifications specified for hybrid DAB operation in the First Report and Order in MM Docket No. 99-325, as revised in the Media Bureau's subsequent Order in MM Docket No. 99-325. FM stations are permitted to operate with hybrid digital effective radiated power equal to one percent (−20 decibels below carrier (dBc)) of authorized analog effective radiated power and may operate with up to ten percent (−10 dBc) of authorized analog effective radiated power in accordance with the procedures set forth in the Media Bureau's Order in MM Docket No. 99-325. An AM or FM station may transmit IBOC signals during all hours for which the station is licensed to broadcast.

(b) In situations where interference to other stations is anticipated or actually occurs, AM licensees may, upon notification to the Commission, reduce the power of the primary DAB sidebands by up to 6 dB. Any greater reduction of sideband power requires prior authority from the Commission via the filing of a request for special temporary authority or an informal letter request for modification of license.

(c) Hybrid IBOC AM stations must use the same licensed main or auxiliary antenna to transmit the analog and digital signals.

(d) FM stations may transmit hybrid IBOC signals in combined mode; i.e., using the same antenna for the analog and digital signals; or may employ separate analog and digital antennas. Where separate antennas are used, the digital antenna:

(1) Must be a licensed auxiliary antenna of the station;

(2) Must be located within 3 seconds latitude and longitude from the analog antenna;

(3) Must have a radiation center height above average terrain between 70 and 100 percent of the height above average terrain of the analog antenna.

(e) Licensees must provide notification to the Commission in Washington, DC, within 10 days of commencing IBOC digital operation. The notification must include the following information:

(1) Call sign and facility identification number of the station;

(2) Date on which IBOC operation commenced;

(3) Certification that the IBOC DAB facilities conform to permissible hybrid specifications;

(4) Name and telephone number of a technical representative the Commission can call in the event of interference;

(5) FM digital effective radiated power used and certification that the FM analog effective radiated power remains as authorized;

(6) Transmitter power output; if separate analog and digital transmitters are used, the power output for each transmitter;

(7) If applicable, any reduction in an AM station's primary digital carriers;

(8) If applicable, the geographic coordinates, elevation data, and license file number of the auxiliary antenna employed by an FM station as a separate digital antenna;

(9) If applicable, for FM systems employing interleaved antenna bays, a certification that adequate filtering and/or isolation equipment has been installed to prevent spurious emissions in excess of the limits specified in §73.317;

(10) A certification that the operation will not cause human exposure to levels of radio frequency radiation in excess of the limits specified in §1.1310 of this chapter and is therefore categorically excluded from environmental processing pursuant to §1.1306(b) of this chapter. Any station that cannot certify compliance must submit an environmental assessment (“EA”) pursuant to §1.1311 of this chapter and may not commence IBOC operation until such EA is ruled upon by the Commission.

[72 FR 45692, Aug. 15, 2007, as amended at 75 FR 17877, Apr. 8, 2010]

Subpart D—Noncommercial Educational FM Broadcast Stations

Source: 28 FR 13651, Dec. 14, 1963, unless otherwise noted. Redesignated at 72 FR 45692, Aug. 15, 2007.

§73.501   Channels available for assignment.

(a) The following frequencies, except as provided in paragraph (b) of this section, are available for noncommercial educational FM broadcasting:

Frequency (MHz)Channel No.
87.91200
88.1201
88.3202
88.5203
88.7204
88.9205
89.12206
89.3207
89.5208
89.7209
89.9210
90.1211
90.3212
90.5213
90.7214
90.9215
91.1216
91.3217
91.5218
91.7219
91.9220

1The frequency 87.9 MHz, Channel 200, is available only for use of existing Class D stations required to change frequency. It is available only on a noninterference basis with respect to TV Channel 6 stations and adjacent channel noncommercial educational FM stations. It is not available at all within 402 kilometers (250 miles) of Canada and 320 kilometers (199 miles) of Mexico. The specific standards governing its use are contained in §73.512.

2The frequency 89.1 MHz, Channel 206, in the New York City metropolitan area, is reserved for the use of the United Nations with the equivalent of an antenna height of 150 meters (492 feet) above average terrain and effective radiated power of 20 kW and the Commission will make no assignments which would cause objectionable interference with such use.

(b) In Alaska, FM broadcast stations operating on Channels 200-220 (87.9-91.9 MHz) shall not cause harmful interference to and must accept interference from non-Government fixed operations authorized prior to January 1, 1982.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[43 FR 39715, Sept. 6, 1978, as amended at 47 FR 30068, July 12, 1982; 52 FR 43765, Nov. 16, 1987; 58 FR 44950, Aug. 25, 1993]

§73.503   Licensing requirements and service.

The operation of, and the service furnished by noncommercial educational FM broadcast stations shall be governed by the following:

(a) A noncommercial educational FM broadcast station will be licensed only to a nonprofit educational organization and upon showing that the station will be used for the advancement of an educational program.

(1) In determining the eligibility of publicly supported educational organizations, the accreditation of their respective state departments of education shall be taken into consideration.

(2) In determining the eligibility of privately controlled educational organizations, the accreditation of state departments of education and/or recognized regional and national educational accrediting organizations shall be taken into consideration.

(b) Each station may transmit programs directed to specific schools in a system or systems for use in connection with the regular courses as well as routine and administrative material pertaining thereto and may transmit educational, cultural, and entertainment programs to the public.

(c) A noncommercial educational FM broadcast station may broadcast programs produced by, or at the expense of, or furnished by persons other than the licensee, if no other consideration than the furnishing of the program and the costs incidental to its production and broadcast are received by the licensee. The payment of line charges by another station network, or someone other than the licensee of a noncommercial educational FM broadcast station, or general contributions to the operating costs of a station, shall not be considered as being prohibited by this paragraph.

(d) Each station shall furnish a nonprofit and noncommercial broadcast service. Noncommercial educational FM broadcast stations are subject to the provisions of §73.1212 to the extent they are applicable to the broadcast of programs produced by, or at the expense of, or furnished by others. No promotional announcement on behalf of for profit entities shall be broadcast at any time in exchange for the receipt, in whole or in part, of consideration to the licensee, its principals, or employees. However, acknowledgements of contributions can be made. The scheduling of any announcements and acknowledgements may not interrupt regular programming.

(e) Mutually exclusive applications for noncommercial educational radio stations operating on reserved channels will be resolved pursuant to the point system in subpart K.

Note to §73.503: Commission interpretation on this rule, including the acceptable form of acknowledgements, may be found in the Second Report and Order in Docket No. 21136 (Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations), 86 FCC 2d 141 (1981); the Memorandum Opinion and Order in Docket No. 21136, 90 FCC 2d 895 (1982), and the Memorandum Opinion and Order in Docket 21136, 97 FCC 2d 255 (1984). See also, “Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations,” Public Notice, 7 FCC Rcd 827 (1992), which can be retrieved through the Internet at http://www.fcc.gov/mmb/asd/nature.html.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13651, Dec. 14, 1963, as amended at 35 FR 7558, May 15, 1970; 47 FR 36178, Aug. 19, 1982; 49 FR 29069, July 18, 1984; 63 FR 33877, June 22, 1998; 65 FR 36378, June 8, 2000]

§73.504   Channel assignments in the Mexican border area.

(a) NCE-FM stations within 199 miles (320 km) of the United States-Mexican border shall comply with the separation requirements and other provisions of the “Agreement between the United States of America and the United Mexican States Concerning Frequency Modulation Broadcasting in the 88 to 108 MHz Band” as amended.

(b) Applicants for noncommercial educational FM stations within 199 miles (320 km) of the United States-Mexican border shall propose at least Class A minimum facilities (see §73.211(a)). However, existing Class D noncommercial educational stations may apply to change frequency within the educational portion of the FM band in accordance with the requirements set forth in §73.512.

(c) Section 73.208 of this chapter shall be complied with as to the determination of reference points and distance computations used in applications for new or changed facilities. However, if it is necessary to consider a Mexican channel assignment or authorization, the computation of distance will be determined as follows: if a transmitter site has been established, on the basis of the coordinates of the site; if a transmitter site has not been established, on the basis of the reference coordinates of the community, town, or city.

[52 FR 43765, Nov. 16, 1987]

§73.505   Zones.

For the purpose of assignment of noncommercial educational FM stations, the United States is divided into three zones, Zone I, Zone I-A, and Zone II, having the boundaries specified in §73.205.

[42 FR 36828, July 18, 1977]

§73.506   Classes of noncommercial educational FM stations and channels.

(a) Noncommercial educational stations operating on the channels specified in §73.501 are divided into the following classes:

(1) A Class D educational station is one operating with no more than 10 watts transmitter power output.

(2) A Class D educational (secondary) station is one operating with no more than 10 watts transmitter power output in accordance with the terms of §73.512 or which has elected to follow these requirements before they become applicable under the terms of §73.512.

(3) Noncommercial educational FM (NCE-FM) stations with more than 10 watts transmitter power output are classified as Class A, B1, B, C3, C2, C1, or C depending on the station's effective radiated power and antenna height above average terrain, and on the zone in which the station's transmitter is located, on the same basis as set forth in §§73.210 and 73.211 for commercial stations.

(b) Any noncommercial educational station except Class D may be assigned to any of the channels listed in §73.501. Class D noncommercial educational FM stations applied for or authorized prior to June 1, 1980, may continue to operate on their authorized channels subject to the provisions of §73.512.

[43 FR 39715, Sept. 6, 1978, as amended at 49 FR 10264, Mar. 20, 1984; 52 FR 47569, Dec. 15, 1987; 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989]

§73.507   Minimum distance separations between stations.

(a) Minimum distance separations. No application for a new station, or change in channel or transmitter site or increase in facilities of an existing station, will be granted unless the proposed facilities will be located so as to meet the adjacent channel distance separations specified in §73.207(a) for the class of station involved with respect to assignment on Channels 221, 222, and 223 listed in §73.201 (except where in the case of an existing station the proposed facilities fall within the provisions of §73.207(b)), or where a Class D station is changing frequency to comply with the requirements of §73.512.

(b) Stations authorized as of September 10, 1962, which do not meet the requirements of paragraph (a) of this section and §73.511, may continue to operate as authorized; but any application to change facilities will be subject to the provisions of this section.

(c)(1) Stations separated in frequency by 10.6 or 10.8 MHz (53 or 54 channels) from allotments or assignments on non-reserved channels will not be authorized unless they conform to the separations in Table A given in §73.207.

(2) Under the United States-Mexican FM Broadcasting Agreement, for stations and assignments differing in frequency by 10.6 to 10.8 MHz (53 or 54 channels), U.S. noncommercial educational FM allotments and assignments must meet the separations given in Table C of §73.207 to Mexican allotments or assignments in the border area.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[42 FR 36828, July 18, 1977, as amended at 43 FR 39716, Sept. 6, 1978; 44 FR 65764, Nov. 15, 1979; 49 FR 10264, Mar. 20, 1984; 49 FR 19670, May 9, 1984]

§73.508   Standards of good engineering practice.

(a) All noncommercial educational stations and LPFM stations operating with more than 10 watts transmitter power output shall be subject to all of the provisions of the FM Technical Standards contained in subpart B of this part. Class D educational stations and LPFM stations operating with 10 watts or less transmitter output power shall be subject to the definitions contained in §73.310, and also to those other provisions of the FM Technical Standards which are specifically made applicable to them by the provisions of this subpart.

(b) The transmitter and associated transmitting equipment of each noncommercial educational FM station and LPFM station licensed for transmitter power output above 10 watts must be designed, constructed and operated in accordance with §73.317.

(c) The transmitter and associated transmitting equipment of each noncommercial educational FM station licensed for transmitter power output of 10 watts or less, although not required to meet all requirements of §73.317, must be constructed with the safety provisions of the current national electrical code as approved by the American National Standards Institute. These stations must be operated, tuned, and adjusted so that emissions are not radiated outside the authorized band causing or which are capable of causing interference to the communications of other stations. The audio distortion, audio frequency range, carrier hum, noise level, and other essential phases of the operation which control the external effects, must be at all times capable of providing satisfactory broadcast service. Studio equipment properly covered by an underwriter's certificate will be considered as satisfying safety requirements.

[65 FR 7640, Feb. 15, 2000]

§73.509   Prohibited overlap.

(a) An application for a new or modified NCE-FM station other than a Class D (secondary) station will not be accepted if the proposed operation would involve overlap of signal strength contours with any other station licensed by the Commission and operating in the reserved band (Channels 200-220, inclusive) as set forth below:

Frequency separation Contour of proposed station Contour of other station
Co-channel0.1mV/m (40 dBu)
1 mV/m (60 dBu)
1 mV/m (60 dBu)
0.1 mV/m (40 dBu)
200 kHz0.5 mV/m (54 dBu)
1 mV/m (60 dBu)1
1 mV/m (60 dBu)
0.5 mV/m (54 dBu)
400 kHz/600 kHz100 mV/m (100 dBu)
1 mV/m (60 dBu)
1 mV/m (60 dBu)
100 mV/m (100 dBu)

(b) An application by a Class D (secondary) station, other than an application to change class, will not be accepted if the proposed operation would involve overlap of signal strength contours with any other station as set forth below:

Frequency separationContour of proposed stationContour of any other station
Co-channel0.1 mV/m (40 dBu)1 mV/m (60 dBu).
200 kHz0.5 mV/m (54 dBu)1 mV/m (60 dBu).
400 kHz10 mV/m (80 dBu)1 mV/m (60 dBu).
600 kHz100 mV/m (100 dBu)1 mV/m (60 dBu).

(c) The following standards must be used to compute the distances to the pertinent contours:

(1) The distance of the 60 dBu (1 mV/m) contours are to be computed using Figure 1 of §73.333 [F(50,50) curves] of this part.

(2) The distance to the other contours are to be computed using Figure 1a of §73.333 [F(50,10) curves]. In the event that the distance to the contour is below 16 kilometers (approximately 10 miles), and therefore not covered by Figure 1a, curves in Figure 1 must be used.

(3) The effective radiated power (ERP) that is the maximum ERP for any elevation plane on any bearing will be used.

(d) An application for a change (other than a change in channel) in the facilities of a NCE-FM broadcast station will be accepted even though overlap of signal strength contours, as specified in paragraphs (a) and (b) of this section, would occur with another station in an area where such overlap does not already exists, if:

(1) The total area of overlap with that station would not be increased;

(2) The area of overlap with any other station would not increase;

(3) The area of overlap does not move significantly closer to the station receiving the overlap; and,

(4) No area of overlap would be created with any station with which the overlap does not now exist.

(e) The provisions of this section concerning prohibited overlap will not apply where the area of such overlap lies entirely over water.

[50 FR 27962, July 9, 1985, as amended at 52 FR 43765, Nov. 16, 1987; 65 FR 79778, Dec. 20, 2000]

§73.510   Antenna systems.

(a) All noncommercial educational stations operating with more than 10 watts transmitter output power shall be subject to the provisions of §73.316 concerning antenna systems contained in subpart B of this part.

(b) Directional antenna. No application for a construction permit of a new station, or change in channel, or change in an existing facility on the same channel will be accepted for filing if a directional antenna with a maximum-to-minimum ratio of more than 15 dB is proposed.

[42 FR 36829, July 18, 1977]

§73.511   Power and antenna height requirements.

(a) No new noncommercial educational station will be authorized with less power than minimum power requirements for commercial Class A facilities. (See §73.211.)

(b) No new noncommercial educational FM station will be authorized with facilities greater than Class B in Zones I and I-A or Class C in Zone II, as defined in §73.211.

(c) Stations licensed before December 31, 1984, and operating above 50 kW in Zones I and I-A, and above 100 kW and in Zone II may continue to operate as authorized.

[50 FR 27963, July 9, 1985, as amended at 50 FR 31379, Aug. 2, 1985; 54 FR 3602, Jan. 25, 1989]

§73.512   Special procedures applicable to Class D noncommercial educational stations.

(a) All Class D stations seeking renewal of license for any term expiring June 1, 1980, or thereafter shall comply with the requirements set forth below and shall simultaneously file an application on FCC Form 340, containing full information regarding such compliance with the provisions set forth below.

(1) To the extent possible, each applicant shall select a commercial FM channel on which it proposes to operate in lieu of the station's present channel. The station may select any commercial channel provided no objectionable interference, as set forth in §73.509(b), would be caused. The application shall include the same engineering information as is required to change the frequency of an existing station and any other information necessary to establish the fact that objectionable interference would not result. If no commerical channel is available where the station could operate without causing such interference, the application shall set forth the basis upon which this conclusion was reached.

(2) If a commercial channel is unavailable, to the extent possible each applicant should propose operation on Channel 200 (87.9 MHz) unless the station would be within 402 kilometers (250 miles) of the Canadian border or 320 kilometers (199 miles) of the Mexican border or would cause interference to an FM station operating on Channels 201, 202, or 203 or to TV Channel 6, as provided in §73.509.

(3) If a channel is not available under either paragraph (a) (1) or (2) of this section, the renewal applicant shall study all 20 noncommercial educational FM channels and shall propose operation on the channel which would cause the least preclusion to the establishment of new stations or increases in power by existing stations. Full information regarding the basis for the selection should be provided.

(b) At any time before the requirements of paragraph (a) become effective, any existing Class D station may file a construction permit application on FCC Form 340 to change channel in the manner described above which shall be subject to the same requirements. In either case, any license granted shall specify that the station's license is for a Class D (secondary) station.

(c) Except in Alaska, no new Class D applications nor major change applications by existing Class D stations are acceptable for filing except by existing Class D stations seeking to change frequency. Upon the grant of such application, the station shall become a Class D (secondary) station.

(d) Class D noncommercial educational (secondary) stations (see §73.506(a)(2)) will be permitted to continue to operate only so long as no interference (as defined in §73.509) is caused to any TV or commercial FM broadcast stations. In the event that the Class D (secondary) station would cause interference to a TV or commercial FM broadcast station after that Class D (secondary) station is authorized, the Class D (secondary) station must cease operation when program tests for the TV or commercial FM broadcast station commence. The Class D (secondary) station may apply for a construction permit (see §73.3533) to change to another frequency or antenna site where it would not cause interference (as defined in §73.509). If the Class D (secondary) station must cease operation before the construction permit is granted, an application for temporary authorization (pursuant to §73.3542) to operate with the proposed facilities may be submitted; where appropriate, such temporary authorization can be granted.

[43 FR 39716, Sept. 6, 1978, as amended at 44 FR 48226, Aug. 17, 1979; 47 FR 28388, June 30, 1982; 50 FR 8326, Mar. 1, 1985]

§73.513   Noncommercial educational FM stations operating on unreserved channels.

(a) Noncommercial educational FM stations other than Class D (secondary) which operate on Channels 221 through 300 but which comply with §73.503 as to licensing requirements and the nature of the service rendered, must comply with the provisions of the following sections of subpart B: §§73.201 through 73.213 (Classification of FM Broadcast Stations and Allocations of Frequencies) and such other sections of subpart B as are made specially applicable by the provisions of this subpart C. Stations in Alaska authorized before August 11, 1982, using Channels 261-300 need not meet the minimum effective radiated power requirement specified in §73.211(a). In all other respects, stations operating on Channels 221 through 300 are to be governed by the provisions of this subpart and not subpart B.

(b) When a noncommercial educational applicant is among mutually exclusive applications for an unreserved FM channel, the mutually exclusive applications will be considered pursuant to Subpart I—Competitive Bidding Procedures and not Subpart K—Application and Selection Procedures On Reserved Noncommercial Educational Channels.

[47 FR 30068, July 12, 1982, as amended at 65 FR 36378, June 8, 2000]

§73.514   Protection from interference.

Permittees and licensees of NCE FM stations are not protected from interference which may be caused by the grant of a new LPFM station or of authority to modify an existing LPFM station, except as provided in subpart G of this part.

[65 FR 67299, Nov. 9, 2000]

§73.515   NCE FM transmitter location.

The transmitter location shall be chosen so that, on the basis of effective radiated power and antenna height above average terrain employed, a minimum field strength of l mV/m (60 dBu) will be provided over at least 50 percent of its community of license or reach 50 percent of the population within the community.

[65 FR 79779, Dec. 20, 2000]

§73.525   TV Channel 6 protection.

The provisions of this section apply to all applications for construction permits for new or modified facilities for a NCE-FM station on Channels 200-220 unless the application is accompanied by a written agreement between the NCE-FM applicant and each affected TV Channel 6 broadcast station concurring with the proposed NCE-FM facilities.

(a) Affected TV Channel 6 station. (1) An affected TV Channel 6 station is a TV broadcast station which is authorized to operate on Channel 6 that is located within the following distances of a NCE-FM station operating on Channels 201-220:

Table A

NCE-FM channelDistance (kilometers)NCE-FM channelDistance (kilometers)
201265211196
202257212195
203246213193
204235214187
205225215180
206211216177
207196217174
208196218166
209196219159
210196220154

(2) Where a NCE-FM application has been accepted for filing or granted, the subsequent acceptance of an application filed by a relevant TV Channel 6 station will not require revision of the pending NCE-FM application or the FM station's authorized facilities, unless the provisions of paragraph (e)(3) of this section for TV translator or satellite stations apply.

(b) Existing NCE-FM stations. (1) A NCE-FM station license authorized to operate on channels 201-220 as of December 31, 1984, or a permittee, granted a construction permit for a NCE-FM station as of December 31, 1984, are not subject to this section unless they propose either:

(i) To make changes in operating facilities or location which will increase predicted interference as calculated under paragraph (e) of this section to TV Channel 6 reception in any direction; or,

(ii) To increase its ratio of vertically polarized to horizontally polarized transmissions.

(2) Applicants must comply with the provision of paragraphs (c) or (d) of this section unless the application for modification demonstrates that, for each person predicted to receive new interference as a result of the change, existing predicted interference to two person will be eliminated. Persons predicted to receive new interference are those located outside the area predicted to receive interference from the station's currently authorized facilities (“existing predicted interference area”) but within the area predicted to receive interference from the proposed facilities (“proposed predicted interference area”). Persons for whom predicted interference will be eliminated are those located within the existing predicted interference area and outside the proposed predicted interference area.

(i) In making this calculation, the provisions contained at paragraph (e) will be used except as modified by paragraph (b)(3) of this section.

(ii) The following adjustment to the population calculation may be made: up to 1,000 persons may be subtracted from the population predicted to receive new interference if, for each person substracted, the applicant effectively installs two filters within 90 days after commencing program tests with the proposed facilities and, no later than 45 days thereafter, provides the affected TV Channel 6 station (as defined in paragraph (a) of this section) with a certification containing sufficient information to permit verification of such installation. The required number of filters will be installed on television receivers located within the predicted interference area; provided that half of the installations are within the area predicted to receive new interference.

(3) Where an NCE-FM applicant wishes to operate with facilities in excess of that permitted under the provisions of paragraphs (c) or (d) of this section, by proposing to use vertically polarized transmissions only, or to increase its ratio of vertically to horizontally polarized transmissions, the affected TV Channel 6 station must be given an option to pay for the required antenna and, if it takes that option, the NCE-FM vertically polarized component of power will be one half (−3 dB) that which would be allowed by the provisions of paragraph (e)(4) of this section.

(4) Applications for modification will include a certification that the applicant has given early written notice of the proposed modification to all affected TV Channel 6 stations (as defined in paragraph (a) of this section).

(5) Where the NCE-FM station demonstrates in its application that it must make an involuntary modification (e.g., due to loss of its transmitter site) that would not otherwise be permitted under this section, its application will be considered on a case-by-case basis. In such cases, the provisions of paragaph (b)(3) of this section do not apply.

(c) New NCE-FM stations. Except as provided for by paragraph (d) of this section, applicants for NCE-FM stations proposing to operate on Channels 201-220 must submit a showing indicating that the predicted interference area resulting from the proposed facility contains no more than 3,000 persons.

(1) In making these calculations, the provisions in paragraph (e) of this section will be used.

(2) The following adjustment to population may be made: up to 1,000 persons may be subtracted from the population within the predicted interference area if, for each person subtracted, the applicant effectively installs one filter within 90 days after commencing program tests and, no later than 45 days thereafter, provides the affected TV Channel 6 station with a certification containing sufficient information to permit verification of such installation. The required number of filters will be installed on television receivers located within the predicted interference area.

(d) Collocated stations. As an alternative to the provisions contained in paragraphs (b) and (c) of this section, an application for a NCE-FM station operating on Channels 201-220 and located at 0.4 kilometer (approximately 0.25 mile) or less from a TV Channel 6 station will be accepted under the following requirements:

(1) The effective radiated power cannot exceed the following values:

Table B

NCE-FM channelPower (kilowatt)NCE-FM channelPower (kilowatt)
2011.121126.3
2021.921231.6
2033.121338.0
2045.021446.8
2058.321556.2
20610.021667.6
20712.021783.2
20814.8218100.0
20917.8219100.0
21021.4220100.0

(2) The NCE-FM application will include a certification that the applicant has coordinated its antenna with the affected TV station by employing either: The same number of antenna bays with radiation centers separated by no more than 30 meters (approximately 100 feet) verticially; or, the FM vertical pattern not exceeding the TV vertical pattern by more than 2dB.

(e) Calculation of predicted interference area and population. Predictions of interference required under this section and calculations to determine the number of persons within a predicted interference area for NCE-FM operation on Channels 201-220 are made as follows:

(1) The predicted interference area will be calculated as follows:

(i) The distances to the TV Channel 6 field strength contours will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,50) curves in Figure 9, §73.699.

(ii) For each TV Channel 6 field strength contour, there will be an associated F(50,10) FM interference contour, the value of which (in units of dBu) is defined as the sum of the TV Channel 6 field strength (in dBu) and the appropriate undesired-to-desired (U/D) signal ratio (in dB) obtained from Figures 1 and 2, §73.599, corresponding to the channel of the NCE-FM applicant and the appropriate F(50,50) field strength contour of the TV Channel 6 station.

(iii) An adjustment of 6 dB for television receiving antenna directivity will be added to each NCE-FM interference contour at all points outside the Grade A field strength contour (§73.683) of the TV Channel 6 station and within an arc defined by the range of angles, of which the FM transmitter site is the vertex, from 110° relative to the azimuth from the FM transmitter site to the TV Channel 6 transmitter site, counterclockwise to 250° relative to that azimuth. At all points at and within the Grade A field strength contour of the TV Channel 6 station, the 6 dB adjustment is applicable over the range of angles from 70° clockwise to 110° and from 250° clockwise to 290°.

(iv) The distances to the applicable NCE-FM interference contours will be predicted according to the procedures specified in §73.313, “Prediction of Coverage,” using the proposed antenna height and horizontally polarized, or the horizontal equivalent of the vertically polarized, effective radiated power in the pertinent direction and the F(50,10) field strength curves (Figure 1a, §73.333).

(v) The predicted interference area will be defined as the area within the TV Channel 6 station's 47 dBu field strength contour that is bounded by the locus of intersections of a series of TV Channel 6 field strength contours and the applicable NCE-FM interference contours.

(vi) In cases where the terrain in one or more directions departs widely from the surrounding terrain average (for example, an intervening mountain), a supplemental showing may be made. Such supplemental showings must describe the procedure used and should include sample calculations. The application must also include maps indicating the predicted interference area for both the regular method and the supplemental method.

(vii) In cases where the predicted interference area to Channel 6 television from a noncommercial educational FM station will be located within the 90 dBu F(50,50) contour of the television Channel 6 station, the location of the FM interfering contour must be determined using the assumption that the Channel 6 field strength remains constant at 90 dBu everywhere within the 90 dBu TV contour. The FM to Channel 6 U/D signal strength ratio specified in §73.599 corresponding to the Channel 6 TV field strength of 90 dBu shall be used.

(2) The number of persons contained within the predicted interference area will be based on data contained in the most recently published U.S. Census of Population and will be determined by plotting the predicted interference area on a County Subdivision Map of the state published for the Census, and totalling the number of persons in each County Subdivision (such as, Minor Civil Division (MCD), Census County Division (CCD), or equivalent areas) contained within the predicted interference area. Where only a portion of County Subdivision is contained within the interference area:

(i) The population of all incorporated places or Census designated places will be subtracted from the County Subdivision population;

(ii) Uniform distribution of the remaining population over the remaining area of the County Subdivision will be assumed in determining the number of persons within the predicted interference area in proportion to the share of the remaining area of the County Subdivision that lies within the predicted interference area; and,

(iii) The population of the incorporated places or Census designated places contained within the predicted interference area will then be added to the total, again assuming uniform distribution of the population within the area of each place and adding a share of the population proportional to the share of the area if only a portion of such a place is within the predicted interference area.

(iv) At the option of either the NCE-FM applicant or an affected TV Channel 6 station which provides the appropriate analysis, more detailed population data may be used.

(3) Adjustments to the population calculated pursuant to paragraph (e)(2) of this section may be made as follows:

(i) If any part of the predicted interference area is within the Grade A field strength contour (§73.683) of a TV translator station carrying the affected TV Channel 6 station, the number of persons within that overlap area will be subtracted, provided the NCE-FM construction permit and license will contain the following conditions:

(A) When the TV translator station ceases to carry the affected TV Channel 6 station's service and the cessation is not the choice of the affected TV Channel 6 station, the NCE-FM station will modify its facilities, within a reasonable transition period, to meet the requirements of this section which would have applied if no adjustment to population for translator service had been made in its application.

(B) The transition period may not exceed 1 year from the date the NCE-FM station is notified by the TV Channel 6 station that the translator station will cease to carry the affected TV Channel 6 station's service or 6 months after the translator station ceases to carry the affected TV Channel 6 station's service, whichever is earlier.

(ii) If any part of the interference area is within the Grade B field strength contour (§73.683) of a satellite station of the affected TV Channel 6 station, the number of persons within the overlap area will be subtracted, provided the NCE-FM permit and license will contain the following conditions:

(A) If the satellite station ceases to carry the affected TV Channel 6 station's service and the cessation is not the choice of the affected TV Channel 6 station, the NCE-FM station will modify its facilities, within a reasonable transition period, to meet the requirements of this rule which would have applied if no adjustment to population for satellite station service had been made in its application.

(B) The transition period may not exceed 1 year from the date the NCE-FM station is notified by the TV Channel 6 station that the satellite station will cease to carry the affected TV Channel 6 stations's service or 6 months after the satellite station ceases to carry the affected TV Channel 6 station's service, whichever is earlier.

(iii) If any part of the predicted interference area is located outside the affected TV Channel 6 station's Area of Dominant Influence (ADI), outside the Grade A field strength contour (§73.683), and within the predicted city grade field strength contour (73.685(a)) of a TV broadcast station whose only network affiliation is the same as the only network affiliation of the affected TV Channel 6 station, the number of persons within that part will be subtracted. (For purposes of this provision, a network is defined as ABC, CBS, NBC, or their successors.) In addition, the ADI of an affected TV Channel 6 station and the program network affiliations of all relevant TV broadcast stations will be assumed to be as they were on the filing date of the NCE-FM application or June 1, 1985, whichever is later.

(iv) In calculating the population within the predicted interference area, an exception will be permitted upon a showing (e.g., as survey of actual television reception) that the number of persons within the predicted interference area should be reduced to account for persons actually experiencing co-channel or adjacent channel interference to reception of the affected TV Channel 6 station. The area within which such a showing may be made will be limited to the area calculated as follows:

(A) The distances to the field strength contours of the affected TV Channel 6 station will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,50) curves in Figure 9, §73.699.

(B) For each field strength contour of the affected TV Channel 6 station, there will be an associated co-channel or adjacent channel TV broadcast station interference contour, the value of which (in units of dBu) is defined as the sum of the affected TV Channel 6 station's field strength (in dBu) and the appropriate undesired-to-desired signal ratio (in dB) as follows:

Co-channel, normal offset, −22 dB

Co-channel, no offset, −39 dB

Adjacent channel, +12 dB

(C) The distances to the associated co-channel or adjacent channel TV broadcast station interference contour will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,10) curves in Figure 9a, §73.699.

(D) The area within which the showing of actual interference may be made will be the area bounded by the locus of intersections of a series of the affected TV Channel 6 station's field strength contours and the associated interference contours of the co-channel or adjacent channel TV broadcast station.

(4) The maximum permissible effective radiated power (ERP) and antenna height may be adjusted for vertical polarity as follows:

(i) If the applicant chooses to use vertically polarized transmissions only, the maximum permissible vertically polarized ERP will be the maximum horizontally polarized ERP permissible at the same proposed antenna height, calculated without the adjustment for television receiving antenna directivity specified in paragraph (e)(1)(iii) of this section, multiplied by either: 40 if the predicted interference area lies entirely outside the limits of a city of 50,000 persons or more; or 10 if it does not.

(ii) If the applicant chooses to use mixed polarity, the permissible ERP is as follows:

[H+(V/A)] is no greater than P

Where:

H is the horizontally polarized ERP in kilowatts for mixed polarity;

V is the vertically polarized ERP in kilowatts for mixed polarity;

A is 40 if the predicted interference area lies entirely outside the limits of a city of 50,000 persons or more, or 10 if it does not; and

P is the maximum permitted horizontally polarized-only power in kilowatts.

(f) Channel 200 Applications. No application for use of NCE-FM Channel 200 will be accepted if the requested facility would cause objectionable interference to TV Channel 6 operations. Such objectionable interference will be considered to exist whenever the 15 dBu contour based on the F(50,10) curves in §73.333 Figure 1a would overlap the 40 dBu contour based on the F(50,50) curves in §73.699, Figure 9.

[50 FR 27963, July 9, 1985; 50 FR 30187, July 24, 1985; 50 FR 31379, Aug. 2, 1985, as amended at 51 FR 26250, July 22, 1986; 52 FR 25867, July 9, 1987; 62 FR 51059, Sept. 30, 1997]

§73.558   Indicating instruments.

The requirements for indicating instruments described in §73.258 are applicable to all educational FM broadcast stations licensed with a transmitter power greater than 0.01 kw.

[51 FR 17029, May 8, 1986]

§73.561   Operating schedule; time sharing.

(a) All noncommercial educational FM stations will be licensed for unlimited time operation except those stations operating under a time sharing arrangement. All noncommercial educational FM stations are required to operate at least 36 hours per week, consisting of at least 5 hours of operation per day on at least 6 days of the week; however, stations licensed to educational institutions are not required to operate on Saturday or Sunday or to observe the minimum operating requirements during those days designated on the official school calendar as vacation or recess periods.

(b) All stations, including those meeting the requirements of paragraph (a) of this section, but which do not operate 12 hours per day each day of the year, will be required to share use of the frequency upon the grant of an appropriate application proposing such share time arrangement. Such applications shall set forth the intent to share time and shall be filed in the same manner as are applications for new stations. They may be filed at any time, but in cases where the parties are unable to agree on time sharing, action on the application will be taken only in connection with the renewal of application for the existing station. In order to be considered for this purpose, such an application to share time must be filed no later than the deadline for filing petitions to deny the renewal application of the existing licensee, or, in the case of renewal applications filed by the existing licensee on or before May 1, 1995, no later than the deadline for filing applications in conflict with the such renewal applications.

(1) The licensee and the prospective licensee(s) shall endeavor to reach an agreement for a definite schedule of periods of time to be used by each. Such agreement shall be in writing and shall set forth which licensee is to operate on each of the hours of the day throughout the year. Such agreement shall not include simultaneous operation of the stations. Each licensee shall file the same in triplicate with each application to the Commission for initial construction permit or renewal of license. Such written agreements shall become part of the terms of each station's license.

(2) The Commission desires to facilitate the reaching of agreements on time sharing. However, if the licensees of stations authorized to share time are unable to agree on a division of time, the Commission shall be so notified by statement to that effect filed with the application proposing time sharing. Thereafter the Commission will designate the application for hearing on any qualification issues arising regarding the renewal or new applicants. If no such issues pertain, the Commission will set the matter for expedited hearing limited solely to the issue of the sharing of time. In the event the stations have been operating under a time sharing agreement but cannot agree on its continuation, a hearing will be held, and pending such hearing, the operating schedule previously adhered to shall remain in full force and effect.

(c) A departure from the regular schedule set forth in a time-sharing agreement will be permitted only in cases where a written agreement to that effect is reduced to writing, is signed by the licensees of the stations affected thereby, and is filed in triplicate by each licensee with the Commission, Attention: Audio Division, Media Bureau, prior to the time of the proposed change. If time is of the essence, the actual departure in operating schedule may precede the actual filing of the written agreement, provided that appropriate notice is sent to the Commission in Washington, DC, Attention: Audio Division, Media Bureau.

(d) In the event that causes beyond the control of a permittee or licensee make it impossible to adhere to the operating schedule in paragraph (a) or (b) of this section or to continue operating, the station may limit or discontinue operation for a period not exceeding 30 days without further authority from the Commission provided that notification is sent to the Commission in Washington, DC, Attention: Audio Division, Media Bureau, no later than the 10th day of limited or discontinued operation. During such period, the permittee shall continue to adhere to the requirements of the station license pertaining to the lighting of antenna structures. In the event normal operation is restored prior to the expiration of the 30 day period, the permittee or licensee will notify the FCC, Attention: Audio Division of the date that normal operations resumed. If causes beyond the control of the permittee or licensee make it impossible to comply within the allowed period, Special Temporary Authority (see §73.1635) must be requested to remain silent for such additional time as deemed necessary. The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12 month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of license to the contrary.

Note 1 to §73.561: For allocations purposes, both (all) stations sharing time will be treated as unlimited time stations.

Note 2 to §73.561: See §§73.1705, 73.1715, and 73.1740.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[43 FR 39717, Sept. 6, 1978, as amended at 43 FR 45845, Oct. 4, 1978; 44 FR 3416, Jan. 19, 1979; 44 FR 65764, Nov. 15, 1979; 47 FR 54448, Dec. 3, 1982; 50 FR 13974, Apr. 9, 1985; 61 FR 18291, Apr. 25, 1996; 61 FR 28767, June 6, 1996; 63 FR 33877, June 22, 1998; 67 FR 13231, Mar. 21, 2002]

§73.567   Determining operating power.

The procedures for determining operating power described in §73.267 are applicable to noncommercial education FM stations.

[44 FR 58732, Oct. 11, 1979]

§73.593   Subsidiary communications services.

The licensee of a noncommercial educational FM station is not required to use its subcarrier capacity, but if it chooses to do so, it is governed by §§73.293 through 73.295 of the Commission's Rules regarding the types of permissible subcarrier uses and the manner in which subcarrier operations shall be conducted; Provided, however, that remunerative use of a station's subcarrier capacity shall not be detrimental to the provision of existing or potential radio reading services for the blind or otherwise inconsistent with its public broadcasting responsibilities.

[48 FR 26615, June 9, 1983]

§73.597   FM stereophonic sound broadcasting.

A noncommercial educational FM broadcast station may, without specific authority from the FCC, transmit stereophonic sound programs upon installation of stereophonic sound transmitting equipment under the provisions of §§2.977, 2.1001, 73.322, and 73.1590 of the FCC's Rules.

[51 FR 17029, May 8, 1986]

§73.599   NCE-FM engineering charts.

This section consists of the following Figures 1 and 2.

eCFR graphic ec01mr91.091.gif

View or download PDF

eCFR graphic ec01mr91.092.gif

View or download PDF

[50 FR 27965, July 9, 1985]

Subpart E—Television Broadcast Stations

§73.601   Scope of subpart.

This subpart contains the rules and regulations (including engineering standards) governing TV broadcast stations, including noncommercial educational TV broadcast stations and, where indicated, low power TV and TV translator stations in the United States, its Territories and possessions. TV broadcast, low power TV, and TV translator stations are assigned channels 6 MHz wide, designated as set forth in §73.603(a).

[47 FR 21494, May 18, 1982]

§73.602   Cross reference to rules in other parts.

See §73.1010.

[43 FR 32781, July 28, 1978]

§73.603   Numerical designation of television channels.

(a)

Channel No.Frequency band (MHz)
254-60
360-66
466-72
576-82
682-88
7174-180
8180-186
9186-192
10192-198
11198-204
12204-210
13210-216
14470-476
15476-482
16482-488
17488-494
18494-500
19500-506
20506-512
21512-518
22518-524
23524-530
24530-536
25536-542
26542-548
27548-554
28554-560
29560-566
30566-572
31572-578
32578-584
33584-590
34590-596
35596-602
36602-608
37608-614
38614-620
39620-626
40626-632
41632-638
42638-644
43644-650
44650-656
45656-662
46662-668
47668-674
48674-680
49680-686
50686-692
51692-698
52698-704
53704-710
54710-716
55716-722
56722-728
57728-734
58734-740
59740-746
60746-752
61752-758
62758-764
63764-770
64770-776
65776-782
66782-788
67788-794
68794-800
69800-806

(b) [Reserved]

(c) Channel 37, 608-614 MHz is reserved exclusively for the radio astronomy service.

(d) In Hawaii, the frequency band 488-494 MHz is allocated for non-broadcast use. This frequency band (Channel 17) will not be assigned in Hawaii for use by television broadcast stations.

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 11179, July 11, 1970; 39 FR 10576, Mar. 21, 1974; 47 FR 16789, Apr. 20, 1982; 47 FR 30068, July 12, 1982; 47 FR 35989, Aug. 18, 1982; 51 FR 18450, May 20, 1986; 70 FR 46676, Aug. 10, 2005]

§73.606   Table of allotments.

(a) General. The following table of allotments contains the channels designated for the listed communities in the United States, its Territories, and possessions. Channels designated with an asterisk are assigned for use by noncommercial educational broadcast stations only. A station on a channel identified by a plus or minus mark is required to operate with its carrier frequencies offset 10 kHz above or below, respectively, the nominal carrier frequencies.

(b) Table of Allotments.

Alabama

  Channel No.
Anniston40-
Arab56-
Bessemer17
Birmingham6-, *10-, 13-, 21-, 42+, *62+, 68-
Decatur
Demopolis*41
Dothan4, 18, *39+, 60-
Dozier*2-
Florence15, 26, *36-
Gadsden44+, 60
Gulf Shores55
Huntsville19, *25+, 31+, 48-
Huntsville-Decatur54
Louisville*43+
Mobile5+, 10+, 15+, 21+, *31, *42
Montgomery12, 20, *26+, 32, 45-, *63
Mount Cheaha*7-
Munford*16-
Opelika50, 66
Ozark34
Selma8, 29-
Troy67
Tuscaloosa23-, 33, *39-
Tuscumbia52+
Tuskegee22-

Alaska

  Channel No.
Anchorage2-, 4-, 5, *7-, *9, 11, 13-, and 33
Bethel*4
Dillingham*2, 10
Fairbanks2+, 7+, *9+, 11+, 13+
Juneau*3, 8, 10
Ketchikan2, 4, *9
North Pole4+
Seward3-,
Sitka13

Arizona

[See footnotes at end of tables]

  Channel No.
Ajo*23-
Coolidge*43
Douglas3, *28
Flagstaff2, 4+, 9, 13, and *16
Globe*14+
Green Valley46
Holbrook*11+, *18+
Kingman6-, *14-
McNary*22+
Mesa12-
Nogales*16+
Page*17
Parker*17-
Phoenix3+, 5-, *8+, 10-, 15-, 21, 33, 39, 45, 61
Prescott7, *19
Safford*23+
Sierra Vista58
Tolleson51
Tucson4-, *6+, 9-, 13-, 18-, *27-, 40
Tucson-Nogales2 11
Yuma11-, 13+, *16-

Arkansas

  Channel No.
Arkadelphia*9+
Camden237A, 246, 49-
Cimarron23
El Dorado10-, 43-
Eureka Springs34+
Fayetteville*13-, 36
Fort Smith5-, 24+, 40-
Gosnell46
Harrison31+
Hot Springs*20, 26
Jonesboro8-, *19+, 48+
Little Rock*2-, 4, 7-, 11, 16-, *36, and 42
Mountain Home43+
Mountain View*6-
Newark*17
Pine Bluff25-, 38-
Rogers51-
Russellville*28+
Springdale57

California

[See footnotes at end of tables]

  Channel No.
Alturas13+
Anaheim56-
Arcata23
Avalon54
Bakersfield17, 23-, 29, *39-, 45, 65+
Barstow*35+, 64
Big Bear Lake59+
Bishop*14-, 20+
Blythe*22-
Brawley*26
Calipatria54
Ceres*23+
Chico12-, *18, 24+, *46-
Clovis43
Coalinga*27-
Concord42
Corona52
Cotati*22-
El Centro7+, 9+
Eureka3-, 6-, *13-, and 29
Fort Bragg8-
Fresno*18+, 24, 30+, 47, 53,
Hanford21
Huntington Beach*50-
Indio*19+
Long Beach18-
Los Angeles2, 4, 5, 7, 9, 11, 13, 22, *28, 34,
*58-, *68-
Merced51
Modesto19-
Novato68
Oakland2+
Ontario46
Oroville28
Oxnard63+
Palm Springs36-, 42
Paradise30
Porterville61
Rancho Palos Verdes44+
Redding7, *9, 16
Ridgecrest*25
Riverside62
Sacramento3, *6, 10, 29-, 31-, 40-
Salinas-Monterey8+, 35-, 46-, *56, 67-
San Bernardino*24-, 30
San Diego8, 10, *15, 39, 51, 69
San Francisco4-, 5+, 7-, *9+, 14+, 20-, 26-, *32+, 38, 44-
San Jose11+, 36, 48-, *54, 65
San Luis Obispo6+, *15+, and 33
San Mateo*60
Sanger59
Santa Anna40,
Santa Barbara3-, 14,1 *20,1 , 38, and *55
Santa Cruz*16-
Santa Maria12+, 42+
Santa Rosa50-, *62
Stockton13+, 58, 64
Susanville*14
Twentynine Palms31
Vallejo-Fairfield66
Ventura57
Visalia26+, *49
Watsonville*25+
Weaverville32
Willits11-
Yosemite Valley41
Yreka City*20+

Colorado

  Channel No.
Alamosa*16, 47
Boulder14
Broomfield*12
Castle Rock53
Colorado Springs11, 13, 21
Craig*16+
Denver2, 4-, *6-, 7, 9-, 20, 31, *41, 50, 59
Durango6+, *20-, and 33+
Fort Collins22-
Glenwood Springs3-, *19+
Grand Junction5-, 8-, *18+, 4*, 11+
Gunnison*17-
La Junta*22+
Lamar12-, *14-
Leadville*15-
Longmont25
Montrose10+, *22
Pueblo5, *8, 32-, 48
Salida*23+
Steamboat Springs24+
Sterling3, *18+
Trinidad*24

Connecticut

  Channel No.
Bridgeport43-, *49-
Hartford3+, 18-, *24, 61+
New Britain30+
New Haven8, 59+, 55
New London26+
Norwich*53
Waterbury20

Delaware

  Channel No.
Dover*34
Seaford38, *64
Wilmington*12, 61

District of Columbia

  Channel No.
Washington4-, 5-, 7+, 9, 20+, *26-, *32+, 50

Florida

  Channel No.
Boca Raton*63
Bradenton*19, 66
Bunnell58
Cape Coral36
Clearwater22
Clermont18-
Cocoa*52, 68
Crystal River39-
Daytona Beach2-, 26
Destin48
Fort Lauderdale51
Fort Myers11+, 20+, *30
Fort Pierce*21-, 34
Fort Walton Beach35, 53, 58
Gainesville*5-, 20, 29
High Springs53+
Hollywood69
Inverness64
Islamorada*9+
Jacksonville4+, *7, 12+, 17, 30+, 47-, *59
Kenansville31
Key West8, *13, and 22+
Lake City*41
Lake Worth67
Lakeland32
Leesburg*45-, 55
Live Oak57-
Madison*36-
Marathon16+
Marianna*16+, 51
Melbourne43+, 56
Miami*2, 4, 6, 7-, 10+, *17-, 23-, 33, 35, 39, and 45+
Naples26-, 46
New Smyrna Beach*15+
Ocala*29, 51-
Orange Park25-
Orlando6-, 9, * 24-, 27, 35+, and 65
Palatka*42, 63+
Palm Beach61
Panama City7+, 13, 28-, *56, 46
Panama City Beach46
Pensacola3-, *23, 33+, 44
St. Petersburg10-, 38, 44+
Sarasota40
Sebring*48, 60
Stuart59
Tallahassee*11-, 24, 27+, 40+
Tampa*3, 8-, 13-, *16, 28, and 50
Tequesta25
Tice49
Venice62
West Palm Beach5, 12, 29+, *42+,

Georgia

  Channel No.
Albany10, 19-, 31-, and 52-
Ashburn*23+
Athens*8-, 34
Atlanta2, 5-, 11+, 17-, *30, 36, 46-, *57+, 69
Augusta6+, 12-, 26, 54-
Bainbridge49
Baxley34
Brunswick21+
Carrollton*49-
Carnesville*52
Cedartown*65-
Chatsworth*18-
Cochran*29+
Columbus3, 9+, *28, 38+, *48, 54+
Cordele55+
Dalton23
Dawson*25
Draketown*27-
Elberton*60+
Flintstone*41-
Lafayette*35
Macon13+, 24+, 41+, *47+, 64-
Monroe63
Pelham*14-
Perry58+
Rome14+
Royston*22+
Savannah3, *9-, 11, 22,
Thomasville6
Toccoa32-, *68-
Valdosta*33, 44-
Vidalia*18+
Warm Springs
Warner Robbins35-
Waycross*8+
Wrens*20-
Young Harris*51-

Hawaii

  Channel No.
Hilo (Hawaii)2, *4, 9, 11, 13, 14+, 20+, 26+, *32+, *38+
Honolulu (Oahu)2+, 4-, 5, 9-, *11+, 13-, 14, 20, 26, 32, *38, and *44.
Kailua50
Kailua-Kona (Hawaii)6
Kaneohe66+
Lihue (Kauai)3+, *8-, 10+, 12-, 15-, *21-, *27-, *67
Wailuku (Maui)3, 7, *10, 12, 15, 21, *27, *33, 39
Waimanalo56

Idaho

  Channel No.
Boise2, *4+, 7, 39
Burley*17+
Caldwell9-
Coeur d'Alene*26+
Filer*19-
Grangeville*15-
Idaho Falls3, 8+, 20, *33+
Lewiston3-
Moscow*35-
Nampa6, 12+
Preston*28
Pocatello6-, *10, 15, 25+, 31-
Sandpoint*16+
Sun Valley5-
Twin Falls11, *13-, 35
Weiser*17

Illinois

[See footnotes at end of tables]

  Channel No.
Aurora60
Bloomington43
Carbondale*8
Champaign3+, 15-
Charleston*51+
Chicago2-, 5, 7, 9+, *11, *20, 26, 32, 38-, 44
Danville68
Decatur17, 23-
DeKalb*33, *48-
East St. Louis46
Edwardsville*18-
Elgin4 66+
Freeport23, *65-
Galesburg53
Harrisburg3
Jacksonville*14
Joliet1 14-, 66+
Kankakee*54-
LaSalle35
Macomb*22+
Marion27
Moline8, *24-
Mount Vernon13+
Olney*16-
Paris46+
Peoria19, 25+, 31+, *47-, 59+
Pontiac53
Quincy10-, 16+, *27+
Rockford13, 17+, 39
Rock Island4+
Springfield20+, 49-, 55+
Streator*63
Urbana*12-, 27-
Vandalia*21

Indiana

  Channel No.
Anderson67+
Angola63
Bloomington4, *30-, 42+ and 63+
Elkhart28+
Evansville7, *9+, 14-, 25-, and 44
Fort Wayne15+, 21+, 33-, *39-, 55
Gary50, *56+
Hammond62+
Indianapolis6, 8-, 13-, *20-, 40, 59-, *69
Kokomo29-
Lafayette18, *24
Madison*60+
Marion23
Muncie49, *61
Richmond43+
Salem58+
South Bend16, 22, *34-, 46
Terre Haute2+, 10, *26-, 38
Vincennes*22-

Iowa

  Channel No.
Ames5, 23-, *34+
Burlington26-, *57-
Carroll*18-, 30+, and 52
Cedar Rapids2, 9-, 28+, and 48-
Centerville*31-
Council Bluffs*32
Davenport6+, 18+, 30-, *36+
Decorah*14+
Des Moines8-, *11+, 13-, 17+, *43-, 63-
Dubuque16-, *29-, 40-
Estherville*49+
Fort Dodge*21
Fort Madison*38+
Hampton50
High Point*14-
Iowa City*12+, 20-
Keokuk*44+
Keosauqua*54+
Lansing*41+
Mason City3+, *24+
Mount Ayr*25-
Newton39+
Ottumwa15+, *33-
Red Oak*36
Rock Rapids*25+
Sibley*33
Sioux City4-, 9, 14, *27-, 44
Spirit Lake*38
Waterloo7+, 22-, *32-

Kansas

  Channel No.
Chanute*30+
Cimarron23
Colby4
Columbus*48-
Dodge City*21-
Emporia*25+
Ensign6+
Fort Scott20+
Garden City11+, 13-, *18
Goodland10
Great Bend2
Hays7-, *9
Hoisington14
Hutchinson*8, 12, 36+
Junction City31
Lakin*3
Lawrence38
Liberal5+
Manhattan*21
Oakley*15-
Parsons*39
Phillipsburg*22-
Pittsburg7+ and 14
Pratt*32+
Randall
Salina18+, 34-, 44
Sedan*28
Topeka*11, 13+, 22+, 27, 49
Wichita3-, 10-, *15+, 24-, 33, *42

Kentucky

  Channel No.
Ashland*25, 50-, 61+
Beattyville65
Blanco52+
Bowling Green13, *24-, 40+, *53-, 59+
Campbellsville34
Covington*54+
Danville56
Elizabethtown*23+
Harlan44-
Hazard*35+, 57-
Hopkinsville51
Lexington18+, 27-, 36, *46, 62
Louisville3-, 11, *15, 21-, 32-, 41+, *68+
Madisonville19-, *35-, and 57+
Morehead*38+, 67-
Murray*21+, 38
Newport19+
Owensboro31-, 48, 61+
Owenton*52+
Paducah6+, 29 and 49
Paintsville69+
Pikeville*22-, 51+
Somerset16, *29+

Louisiana

  Channel No.
Alexandria5, *25+, 31+, 41+
Baton Rouge2, 9-, *27+, 33-, and 44+
Columbia11+
De Ridder*23-
Houma11
Lafayette3+, 10, 15, *24
Lake Charles7-, *18-, 29-
Minden21+
Monroe8+, *13,
Morgan City*14+
Natchitoches*20+
New Iberia50
New Orleans4+, 6, 8-, * 12, 20-, 26, * 32+, 38+, and 49
Shreveport3-, 12, *24-, 33, and 45+
Slidell54+
Tallulah*19
West Monroe14-, 39+

Maine

  Channel No.
Augusta*10-
Bangor2-, 5+, 7-
Biddeford*26-
Calais*13-
Fort Kent*46+
Fryeburg*18+
Houlton*25+
Kittery*39
Lewiston35-
Millinocket*44-
Orono*12-
Poland Spring 8-
Portland6-, 13+, 51
Presque Isle8, *10+, 47
Rumford*43+
Waterville23-

Maryland

  Channel No.
Annapolis*22+
Baltimore2+, 11-, 13+, 24+, 45, 54, *67-
Cumberland52+, 65
Frederick*62
Hagerstown25-, *31, and 68+
Oakland*36+
Salisbury16+, *28-, 47-
Waldorf*58+

Massachusetts

[See footnotes at end of tables]

  Channel No.
Adams19
Boston*2+, 4+, 5-, 7+, 25+, 38, *44, 68+
Cambridge56
Greenfield32+
Lawrence62
Marlborough66
New Bedford6+, 28-, *34
North Adams*35
Norwell46+
Pittsfield51+
Springfield22, 40, *57+
Vineyard Haven58+
Worcester14, 1 27, *48+,

Michigan

  Channel No.
Alpena*6, 11
Ann Arbor31+, *58+
Bad Axe* 15-, 41-
Battle Creek41+, and 43-
Bay City5-, 46+
Cadillac9, *27, 33
Calumet5-, *22-
Cheboygan4+
Detroit2+, 4, 7-, 20+, 50-, *56, 62
East Lansing*23-, *69-
Escanaba3+
Flint12-, *28-, 66-
Grand Rapids8+, 13+, 17-, *35+
Iron Mountain8-, *17+
Ironwood*15-, 24+
Ishpeming10
Jackson18+
Kalamazoo3-, *52+, 64
Lansing6-, 47, 53-
Manistee*21
Manistique*15+
Marquette6-, *13, 19
Mount Clemens38+
Mount Pleasant*14
Muskegon54+
Onondaga10-
Petoskey*23+
Port Huron46+
Saginaw25-, 49-
Sault Ste. Marie8, 10+, *32-
Traverse City7+, 29-
University Center *19+
Vanderbilt45
West Branch*24

Minnesota

  Channel No.
Alexandria7, * 24, and 42
Appleton*10-
Austin6-, *15-
Bemidji*9, 26+
Brainerd*22
Chisholm11
Crookston*33
Duluth3, *8, 10+, 21+, 27-
Ely*17-
Fairmont*16+
Hibbing13-
International Falls*35+
Mankato12, *26-
Marshall*30-
Minneapolis-St. Paul*2-, 4, 5-, 9+, 11-, *17, 23+, 29+, and 45
Redwood Falls43
Rochester10, 47-
St. Cloud19, *25-, 41
St. James32+
Thief River Falls10, *30
Wadena*20-
Walker12-, 38-
Wilmar*14-
Winona*35+, 44-
Worthington*20

Mississippi

  Channel No.
Biloxi13+, *19+,
Booneville*12-
Bude*17+
Clarksdale*21
Cleveland*31-
Columbia*45
Columbus4-, *43
Greenville15-, 44
Greenwood6+, *23+
Gulfport25-
Grenada22+
Hattiesburg22, *47
Holly Springs40
Houston45+
Jackson3, 12+, 16, *29+, 40+, and 51
Laurel7, 18+
Magee34+
Meridian11-, *14, 24-, 30-
Mississippi State*2+
Natchez*42+, 48
Oxford*18
Senatobia*34-
Tupelo9-, 49+
Vicksburg35-
West Point27
Wiggins43-, 46-
Yazoo City*32-

Missouri

  Channel No.
Birchtree*20-
Bowling Green*35+
Cape Girardeau12, 23, *39-
Carrollton*18
Columbia8+, 17-*23+
Flat River*22
Hannibal7-
Jefferson City13, 25, *36-
Joplin12+, 16, *26-
Kansas City4, 5+, 9+, *19+, 29, 41-, 50-, 62+, *68-
Kennett58+
King City*28-
Kirksville3-
LaPlata*21+
Lowry City*15-
Osage Beach49+
Poplar Bluff15+, *26+, 55
Rolla*28
St. Joseph2-, 16-, 22
St. Louis2, 4-, 5-, *9, 11-, 24+, 30+, *40-, *46
Sedalia6
Sikeston45
Springfield3+, 10, *21-, 27-, 33--

Montana

  Channel No.
Anaconda2+
Billings2-, 6, 8, *11, 14, 20+
Bozeman7-, *9
Butte*2+, 4, 6+, 18, 24
Cut Bank*14-
Dillon*14+
Glendive5+, 13+, *16-
Great Falls3+, 5+, 16, 26, *32
Hardin4+
Havre9+, 11-, and *18-
Helena10+, 12, *15+
Joplin35-, 48, 54-
Kalispell9-, *29-
Lewistown13
Miles City3-, *10
Missoula8-, *11+, 13-, 17-, and 23-
Wolf Point*17+

Nebraska

  Channel No.
Albion18, *21+, 24+
Alliance*13-
Bassett*7-
Beatrice23+
Falls City*24
Grand Island11-, 17
Hastings5-, *29+
Hayes Center6
Hay Springs-Scottsbluff4+
Kearney13
Lexington*3+
Lincoln8+, 10+, *12-, 45, 51
McCook8-, 16+, 12
Merriman*12
Norfolk*19+
North Platte235, 246, 278
Omaha3, 6+, 7, 15, *26, 42+, *48-, and 54
Orchard16
Pawnee33+
Scottsbluff10-, 16
Superior4+

Nevada

  Channel No.
Elko10-, *14+
Ely3-, 6+
Fallon*25
Goldfield7-
Henderson5+
Las Vegas3, 8-, *10+, 13-, 15+, 21+, and 33+
Laughlin34+
McGill*13
Paradise39+
Pawnee City*33+
Reno2, 4, *5, 8, 11, 21+, and 27+
Tonopah9-, *17+
Winnemucca7+, *15-
Yerington*16+

New Hampshire

[See footnotes at end of tables]

  Channel No.
Berlin*40-
Concord21+
Derry50-
Durham*11
Hanover*15+
Keene*52+
Littleton*49+
Manchester9-,
Merrimack60+
Portsmouth1 17-

New Jersey

  Channel No.
Atlantic City*36, 53+, 62-
Burlington48-
Camden*23+
Linden-Newark47+
Montclair*50+
Newark13-, 68
New Brunswick*58
Newton63
Paterson41-
Secaucus9+
Trenton*52-
Vineland59-, 65-
West Milford*66-
Wildwood40

New Mexico

  Channel No.
Alamogordo*18-
Albuquerque4+, *5+, 7+, 13+, 14-, 23-, *32+, 41, 50
Carlsbad6-, *15+, 25-
Clayton*17
Clovis12--
Deming*16
Farmington3, 12+, *15+
Gallup*8-, 10
Hobbs29+
Las Cruces*22-, 48+
Lovington*19
Portales*3+
Raton*18-
Roswell8, 10-, 21-, 27-, *33+
Santa Fe2+, *9+, 11-, 19-
Silver City6, 10+, *12
Socorro*15-
Tucumcari*15

New York

[See footnotes at end of tables]

  Channel No.
Albany-Schenectady6, 10-, 13, *17+, 23-, *29+, 45
Amsterdam*39+, 55
Arcade62-
Batavia51-
Bath14-
Binghamton12-, 34, 40-, *46+
Buffalo2, 4, 7+, 17, *23, 29-, 49-
Carthage7-
Corning*30, 48+
Elmira18+, 36-
Garden City*21-
Glens Falls*58-
Ilion67-
Ithaca52, *65+
Jamestown26+, *46
Kingston62+
Lake Placid*34+
New York2, 4, 5+, 7, 11+, *25, 31-
North Pole5
Norwood*18
Oneonta1 15, *42
Plattsburg*57
Poughkeepsie54+
Riverhead55+
Rochester8, 10+, 13-, *21, 31+, *61+
Saranac Lake40+
Smithtown67
Springville67+
Syracuse3-, 5-, 9-, *24+, 43+, 56+, 68-
Utica2-, 4-, 20+, 33, *59
Watertown*16, 50+
Waverly*57-

North Carolina

  Channel No.
Andrews*59
Asheville13-, 21+, *33, 62+
Belmont46+
Bryson City*67
Burlington16
Canton*27
Chapel Hill*4+
Charlotte3, 9+, 18, 36, *42+
Concord*58
Cullowhee50+
Durham11+, 28+
Edenton*2
Fayetteville40+, 62
Forest City66+
Franklin*56+
Goldsboro17-
Greensboro2-, 48-, 61
Greenville9-, 14, *25, and 38+
Hickory14-
High Point8-, *32+, 67+
Jacksonville*19, 35
Kannapolis64-
Laurel Hill59+
Lexington20
Linville*17
Lumberton*31
Manteo4
Morehead City8+
Morganton23-
New Bern12+
Raleigh5, 22, *34, 50+
Roanoke Rapids*36-
Rockingham*53
Rocky Mount47+
Washington7
Waynesville59
Wilmington3-, 6, 26-, *39-
Wilson30-
Winston-Salem12, *26+, 45

North Dakota

  Channel No.
Bismarck*3, 5, 12-, 17-, 26+
Devils Lake8+, *22+
Dickinson2+, *9-, 7
Ellendale*19-
Fargo6, 11+, *13, 15-
Grand Forks*2, 14+, 27+
Jamestown7-, *23
Minot*6+, 10-, 13-, 14-, 24
Pembina12
Valley City4-
Williston*4, 8-, 11-, *15-

Ohio

[See footnotes at end of tables]

  Channel No.
Akron23+, *49+, 55-
Alliance*45+
Ashtabula1 15
Athens20*, 63-
Bowling Green*27+
Cambridge*44-
Canton17-, 67
Chillicothe53
Cincinnati5-, 9, 12, *48-, 64-
Cleveland3, 5+, 8, *25+, 61
Columbus4-, 6+, 10+, 28-, *34, *56-
Dayton2, 7+, *16+, 22+, 45
Defiance65+
Hillsboro*24+, 55+
Lima35-, 44+, *57+, 17
Lorain43
Mansfield*47+, 68-
Newark*31-, 51
Oxford*14+
Portsmouth30, *42-
Sandusky52
Shaker Heights 19
Springfield26+, *66
Steubenville9+, *62+
Toledo11-, 13, 24-, *30+, 36-, and 40-
Xenia32
Youngstown21-, 27, 33, *58
Zanesville18-

Oklahoma

[See footnotes at end of tables]

  Channel No.
Ada10+, *22
Altus*27
Ardmore*17, *28-
Bartlesville17+
Cheyenne12+
Claremore*35
Duncan40+
Elk City*15-
Enid20-, *26+
Eufaula*3
Grove45+
Guymon9+, *16
Hugo42+, 1 *15+, *48+
Lawton7+, *36-, 16-, 45
McAlester*32-
Miami*18-
Muskogee19
Norman46-
Oklahoma City4-, 5, 9-, *13, 14-, 25-, 34-, 43+, 52, and 62+
Okmulgee44-
Sayre8+
Shawnee30
Tulsa2+, 6+ 8-, *11-, 23, 41+, 47, 53
Woodward*17-, 35+

Oregon

  Channel No.
Astoria*21
Bend*3+, *15, 21+, 51
Brookings*14-
Burns*18
Coos Bay11, 23+, 41
Corvallis*7-
Eugene9+, 13, 16+, *28-, and 34
Grants Pass*18+, 30+
Klamath Falls2-, *22+, and 31
LaGrande*13+, 16
Medford5, *8+, 10+, 12+, and 26+
North Bend*17+
Pendleton11-
Portland2, 6+, 8-, *10, 12, 24+, *30, 40-
Roseburg4+, 36, 46+
Salem22, 32
The Dalles*17-

Pennsylvania

[See footnotes at end of tables]

  Channel No.
Allentown*39, 69
Altoona10-, 23-, 47, *57+
Bethlehem60-
Clearfield*3+
Erie12, 24, 35+, *54+, 66+
Greensburg40+
Harrisburg21+, 27-, *33+
Hazleton56
Jeanette19+
Johnstown6, 8-, 19+, *28+
Lancaster8+, 15+
Lebanon55-
Philadelphia3, 6-, 10, 17-, 29, *35-, 57
Pittsburgh2-, 4+, 11, *13-, 16, 22, 53+
Reading51
Red Lion49+
Scranton16-, 22-, 38+, *44-, 64
State College29+, and *59+
Wilkes Barre28
Williamsport1 20-, 53-
York43,

Rhode Island

[See footnotes at end of tables]

  Channel No.
Block Island69-
Providence10+, 12+, 1 16, *36, 64+

South Carolina

  Channel No.
Aiken*44
Allendale*14
Anderson40
Beaufort*16-
Charleston2+, 4, 5+, *7-, 24, and 36+
Columbia10-, 19+, 25-, *35+, 47, 57-
Conway*23+
Florence13+, 15-, 21, *33+
Greenville4-, 16+, 21, *29
Greenwood*38, 48+
Hardeeville28-
Myrtle Beach32, 43+
Rock Hill30+, 55-
Spartanburg7+, 49
Sumter*27- and 63-

South Dakota

  Channel No.
Aberdeen9-, *16-
Allen22+
Brookings*8
Eagle Butte*13
Florence3-
Huron12+
Lead5-, 11+
Lowry*11-, 56, 62+, 68-
Martin*8-
Mitchell5+
Pierre4, *10+
Rapid City3+, 7+, *9, 15-, 21-
Reliance6-
Seneca*2-
Sioux Falls11, 13+, 17-, *23, 36+, 46
Vermillion*2+

Tennessee

  Channel No.
Athens*24
Chattanooga3+, 9, 12+, *45, 61-
Cleveland53
Cookeville*22, 28+
Crossville20+, *55+
Fayetteville*29-
Greeneville39-
Hendersonville50
Jackson7+, 16+, *32+
Jellico54-
Johnson City11-, *41
Kingsport19
Knoxville6, 8, 10+, *15-, 43+
Lebanon66--
Lexington*11+
Livingston60-
McMinnville33+
Memphis3-, 5+, *10+, 13+, *14+, 24, 30, 50+, and *56
Murfreesboro39+
Nashville2-, 4+, 5, *8+, 17+, 30+, *42, and 58
Sneedville*2+
Tazewell48+
Tullahoma64+
Union City41

Texas

  Channel No.
Abilene9+, 15, *26+, 32+
Alpine12-
Alvin67
Amarillo*2+, 4, 7, 10, 14+
Austin7+, *18+, 24, 36, 42-, and 54
Bay City*43+
Baytown57+
Beaumont6-, 12-, 21, *34-
Belton46-
Big Spring4-, *14
Blanco17
Boquillas8-
Borger31
Brady13
Brownsville23
Bryan3, 28
Childress*21
College Station*15, 50-
Conroe49+ and 55+
Corpus Christi3-, 6, 10-, *16, 28-, 38+
Crockett40
Dallas4+, 8, *13+, 27-, 33+, 39, and 58
Decatur29
Del Rio10, *24+
Denton*2
Eagle Pass16+
El Paso4, 7, 9, *13, 14, 26+, *38--, and 65
Farwell18+
Fort Stockton5+
Fort Worth5+, 11-, 21-, *31+, and 52-
Fredericksburg2+
Galveston*22, 47
Garland23
Greenville47+
Harlingen4+, *44, 60
Houston2-, *8, 11+, 13-, *14, 20, 26, 39-, and 61
Irving49
Jacksonville56
Katy51+
Kennville35+
Killeen62
Lake Dallas55
Laredo8, 13, 27-, *39
Liano14-
Longview16+, 38-, and 51-
Lubbock*5-,11,13-, 16+, 28, and 34-
Lufkin9
McAllen48
Marfa3
Marshall*22-, 35+
Midland2-, 18
Mineola64+
Monahans-Odessa9-
Nacogdoches19-, *32
Odessa7-, 24-, 30, *36+, and 42
Palestine43
Paris, Texas36+, 42+
Port Arthur4-
Presidio7+
Rio Grande City40
Rosenberg45
San Angelo3-, 6, 8+, *21+
San Antonio4, 5, *9-, 12+, *23-, 29+, 41+, and 60+
Sherman12-, 20-, *26-
Snyder17-
Sonora11+
Sulphur Springs18
Sweetwater12
Temple6+,
Texarkana6, 17-, *34
Tyler7,14+, *38, and 60
Uvalde26-
Victoria19+, 25, 31, and *47
Waco10+, 25+, *34+, 44-
Weslaco5-
Wichita Falls3+, 6-, 18-, *24
Wolfforth22-

Utah

  Channel No.
Cedar City4, *16+
Logan12-, *22
Moab*14+
Monticello*16-
Ogden*9+, *18-, 24, 30
Price3+, *15
Provo*11-, 16, 32
Richfield8+, *19
Salt Lake City2-, 4-, 5+, *7-, 13+, 14-, 20+, *26-
St. George12, *18-
Vernal6, *17+

Vermont

  Channel No.
Burlington3, 22+, *33-, 44+
Hartford31
Rutland*28+
St. Johnsbury*20-
Windsor*41

Virginia

  Channel No.
Arlington14-
Ashland65+
Blacksburg*43, 65-
Bristol5+, *28-
Bluefield*63+
Charlottesville29-, *41-, 64+
Courtland*52
Danville24-, 44+, *56
Farmville*31-
Fairfax*56-
Fredericksburg69+
Front Royal*42
Goldvein*53
Grundy68
Harrisonburg3-
Lynchburg13, 21-, *54+
Manassas66+
Marion*52-
Norfolk-Portsmouth-Newport News-3+, 10+, 13-, *15, 27, 33, 49- and
Hampton*55+
Norton*47-
Onancock*25+
Petersburg8
Richmond6+, 12-, *23, 35+, *57-, 63
Roanoke7-, 10, *15+, 27+, 38-, and 60
Staunton*51-
Virginia Beach21+, 43+
West Point*46

Washington

  Channel No.
Anacortes64
Bellevue33+, 51+
Bellingham12+, 24, *34
Centralia*15+
East Wenatchee249A
Everett16-
Kennewick42+
Morton39
Olympia67
Pasco19-
Pullman*10-, 24+
Richland25, *31
Rochester26+
Seattle4, 5+, 7, *9, 22+, 45+, and *62
Spokane2-, 4-, 6-,*7+22, 28-, and 34-
Tacoma11+, 13-, 20, *28, and *56
Vancouver*14, 49
Walla Walla9+
Wenatchee*18+, 27
Yakima23+, 29+, 35, *47

West Virginia

[See footnotes at end of tables]

  Channel No.
Bluefield6-, 40-
Charleston8+, 11+, 29, *49-
Clarksburg12+, 46-
Fairmont66-
Grandview*9-
Huntington3+, 13+, *33+
Keyser*30+
Lewisburg59
Martinsburg*44, 60+
Morgantown*24-
Oak Hill4
Parkersburg15-, 39+, *57
Weirton*50+
Weston5
Wheeling7, 1 14, *41
Williamson*31+

Wisconsin

  Channel No.
Antigo46
Appleton32+
Bloomington*49
Chippewa Falls48
Crandon4
Eagle River34
Eau Claire13+, 18
Fond du Lac68
Green Bay2+, 5+, 11+, 26+, *38, 50+
Highland*51
Janesville57+
Kenosha55-
Kieler*46+
LaCrosse8+, 19+, 25, *31
Madison3, 15, *21-, 27+, 47+
Manitowoc16+
Marshfield39-
Mayville52
Menomonie*28-
Milwaukee4-, 6, *10+, 12, 18-, 24+, 30, *36, and 58
Oshkosh22+and *50+
Park Falls*36+
Racine49+
Rhinelander12+
Rice Lake16
Richland Center45+
Sheboygan28
Sturgeon Bay42
Superior6+, 40
Suring14-
Tomah43
Wausau7-, 9, *20+, 33-
Wittenberg55

Wyoming

  Channel No.
Casper2+, *6+, 13+, 14-, 20-
Cheyenne5+, *17, 27-, 33-
Jackson2, 11+
Lander*4, 5
Laramie*8+
Rawlins11-
Riverton10+
Rock Springs13
Sheridan7, 9+, 12+

U.S. Territories and Possessions

[See footnotes at end of tables]

  Channel No.
Guam:
Agana*4, 8, 10, *12
Tamuning14, 20
Puerto Rico:
Aguada50
Aguadilla*32, 44
Arecibo-Aguadilla12+
Arecibo54, 60
Bayamon36
Caguas11-, *58
Carolina52
Cayey
Fajardo13+, 34, and *40
Guayama46
Humacoa68
Mayaguez3+, 5-, 16, 22
Naranjito64
Ponce7+, 9-, 14, 20, *26, 48
San Juan2+, 4-, *6+, 18, 24, 30, and *62
San Sebastian38
Utuado
Yauco42
Virgin Islands:
Charlotte Amalie10-, 17, *23, 43
Charlotte Amalie-Christiansted*3, 6 *12
Christiansted8+, 15, *21, 39
Frederiksted66

Footnotes to tables:

1Following the decision in Docket No. 18261, channels so indicated will not be available for television use until further action by the Commission.

2Operation on this channel is subject to the conditions, terms, and requirements set out in the Report and Order in Docket No. 19075, RM-1645, adopted January 5, 1972, released January 7, 1972, FCC 72-19.

3[Reserved]

4This channel is not available for use at Elgin unless and until it is determined by the Commission that it is not needed for use at Joliet, Ill.

5[Reserved]

6Stations using these allotments shall limit radiation toward stations on the same channel in Puerto Rico, to no more than the effective radiated power which would be radiated by an omnidirectional radio station using maximum permissible effective radiated power for antenna height above average terrain, at the minimum distances from such stations specified in Sec. 73.610(b). The FCC shall consider the status of the negotiations with the appropriate British authorities concerning these allotments when the applications for construction permits come before the FCC.

(Sec. 5, 48 Stat. 1068; 47 U.S.C. 155)

[28 FR 13660, Dec. 14, 1963]

Editorial Note: For Federal Register citations affecting §73.606, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.

§73.607   Availability of channels.

(a) Applications may be filed to construct TV broadcast stations only on the channels designated in the Table of Allotments (§73.606(b)) and only in the communities listed therein. Applications which fail to comply with this requirement, whether or not accompanied by a petition to amend the Table, will not be accepted for filing. However, applications specifying channels which accord with publicly announced FCC Orders changing the Table of Allotments will be accepted for filing even though such applications are tendered before the effective dates of such channel changes.

(b) Notwithstanding paragraph (a) of this section, an application may be filed for a channel or community not listed in the TV Table of Allotments if it is consistent with the rules and policies established in the Third Report and Order in WT Docket 99-168 (FCC 01-25), adopted January 18, 2001. Where such a request is approved, the Media Bureau will change the Table of Allotments to reflect that approval.

[51 FR 44070, Dec. 8, 1986, as amended at 66 FR 10208, Feb. 14, 2001; 67 FR 13232, Mar. 21, 2002]

§73.609   Zones.

(a) For the purpose of allotment and assignment, the United States is divided into three zones as follows:

(1) Zone I consists of that portion of the United States located within the confines of the following lines drawn on the U.S. Albers Equal Area Projection Map (based on standard parallels 2912 ° and 4512 °; North American datum): Beginning at the most easterly point on the State boundary line between North Carolina and Virginia; thence in a straight line to a point on the Virginia-West Virginia boundary line located at north latitude 37°49 and west longitude 80°1230; thence westerly along the southern boundary lines of the States of West Virginia, Ohio, Indiana, and Illinois to a point at the junction of the Illinois, Kentucky, and Missouri State boundary lines; thence northerly along the western boundary line of the State of Illinois to a point at the junction of the Illinois, Iowa, and Wisconsin State boundary lines; thence easterly along the northern State boundary line of Illinois to the 90th meridian; thence north along this meridian to the 43.5° parallel; thence east along this parallel to the United States-Canada border; thence southerly and following that border until it again intersects the 43.5° parallel; thence east along this parallel to the 71st meridian; thence in a straight line to the intersection of the 69th meridian and the 45th parallel; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a city, the city shall be considered to be located in Zone I. (See Figure 1 of §73.699.)

(2) Zone II consists of that portion of the United States which is not located in either Zone I or Zone III, and Puerto Rico, Alaska, Hawaiian Islands and the Virgin Islands.

(3) Zone III consists of that portion of the United States located south of a line, drawn on the United States Albers Equal Area Projection Map (based on standard parallels 29.50 and 45.50 North American datum), beginning at a point on the east coast of Georgia and the 31st parallel and ending at the United States-Mexican border, consisting of arcs drawn with a 241.4 kilometer (150 mile) radius to the north from the following specified points:

  North latitudeWest longitude
(a)29°400083°2400
(b)30°070084°1200
(c)30°310086°3000
(d)30°480087°5830
(e)30°000090°3830
(f)30°043093°1900
(g)29°460095°0500
(h)28°430096°3930
(i)27°523097°3200

When any of the above arcs pass through a city, the city shall be considered to be located in Zone II. (See Figure 2 of §73.699.)

[28 FR 13660, Dec. 14, 1963, as amended at 33 FR 15422, Oct. 17, 1968; 50 FR 23697, June 5, 1985; 51 FR 44070, Dec. 8, 1986]

§73.610   Minimum distance separations between stations.

(a) The provisions of this section relate to allotment separations and station separations. Petitions to amend the Table of Allotments (§73.606(b)) (other than those also expressly requesting amendment of this section or §73.609) will be dismissed and all applications for new TV broadcast stations or for changes in the transmitter sites of existing stations will not be accepted for filing if they fail to comply with the requirements specified in paragraphs (b), (c) and (d) of this section.

Note: Licensees and permittees of television broadcast stations which were operating on April 14, 1952 pursuant to one or more separations below those set forth in §73.610 may continue to so operate, but in no event may they further reduce the separations below the minimum. As the existing separations of such stations are increased, the new separations will become the required minimum separations until separations are reached which comply with the requirements of §73.610. Thereafter, the provisions of said section shall be applicable.

(b) Minimum co-channel allotment and station separations:

(1)

ZoneKilometers
Channels 2-13Channels 14-69
I272.7 (169.5 miles)248.6 (154.5 miles)
II304.9 (189.5 miles)280.8 (174.5 miles)
III353.2 (219.5 miles)329.0 (204.5 miles)

(2) The minimum co-channel distance separation between a station in one zone and a station in another zone shall be that of the zone requiring the lower separation.

(c) Minimum allotment and station adjacent channel separations applicable to all zones:

(1) Channels 2-13 95.7 kilometers (59.5 miles). Channels 14-69 87.7 kilometers (54.5 miles).

(2) Due to the frequency spacing which exists between Channels 4 and 5, between Channels 6 and 7, and between Channels 13 and 14, the minimum adjacent channel separations specified above shall not be applicable to these pairs of channels (see §73.603(a)).

(d) In addition to the requirements of paragraphs (a), (b) and (c) of this section, the minimum assignment and station separations between stations on Channels 14-69, inclusive, as set forth in Table II of §73.698 must be met in either rule-making proceedings looking towards the amendment of the Table of Assignments (§73.606(b)) or in licensing proceedings. No channel listed in column (1) of Table II of §73.698 will be assigned to any city, and no application for an authorization to operate on such a channel will be granted, unless the distance separations indicated at the top of columns (2) through (7), inclusive, are met with respect to each of the channels listed in those columns and parallel with the channel in column (1).

(e) The zone in which the transmitter of a television station is located or proposed to be located determines the applicable rules with respect to co-channel distance separations where the transmitter is located in a different zone from that in which the channel to be employed is located.

(f) The distances listed below apply only to allotments and assignments on Channel 6 (82-88 MHz). The Commission will not accept petitions to amend the Table of Allotments, applications for new stations, or applications to change the channel or location of existing assignments where the following minimum distances (between transmitter sites, in kilometers) from any FM Channel 253 allotment or assignment are not met:

Minimum Distance Separation from FM Channel 253 (98.5 MHz)

Fm ClassTV Zone ITV Zones II & III
A1722
B11923
B2226
C31923
C22226
C12933
C3641

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13660, Dec. 14, 1963, as amended at 37 FR 25842, Dec. 5, 1972; 44 FR 65765, Nov. 15, 1979; 47 FR 35990, Aug. 18, 1982; 50 FR 23698, June 5, 1985; 51 FR 44070, Dec. 8, 1986; 54 FR 14964, Apr. 14, 1989; 54 FR 16368, Apr. 24, 1989; 54 FR 35340, Aug. 25, 1989]

§73.611   Reference points and distance computations.

(a) In considering petitions to amend the Table of Allotments (§73.606(b)), the following reference points shall be used by the Commission in determining assignment separations between communities:

(1) Where transmitter sites for the pertinent channels have been authorized in communities involved in a petition to amend the Table of Allotments, separations between such communities shall be determined by the distance between the coordinates of the authorized transmitter sites in the respective communities as set forth in the Commission's authorizations therefor.

(2) Where an authorized transmitter site is available for use as a reference point in one community but not in the other for the pertinent channels, separations shall be determined by the distance between the coordinates of the transmitter site as set forth in the FCC's authorization therefor and the coordinates of the other community as set forth in the publication of the United States Department of the Interior entitled, Index to The National Atlas of the United States of America. If this publication does not contain the coordinates for said other community, the coordinates of the main post office thereof shall be used.

(3) Where no authorized transmitter sites are available for use as reference points in both communities for the pertinent channels, the distance between the two communities listed in the above publication shall be used. If said publication does not contain such distance, the separation between the two communities shall be determined by the distance between the coordinates thereof as set forth in the publication. Where such coordinates are not contained in the publication, the coordinates of the main post offices of said communities shall be used.

(4) Where the distance between the reference point in a community to which a channel is proposed to be assigned and the reference point in another community or communities does not meet the minimum separation requirements of §73.610, the channel may be assigned to such community upon a showing that a transmitter site is available that would meet the minimum separation requirements of §73.610 and the minimum field strength requirements of §73.685. In such cases, where a station is not authorized in the community or communities to which measurements from the proposed channel assignment must be made pursuant to §73.610 a showing should also be made that the distance between suitable transmitter sites in such other community or communities and the proposed transmitter site for the new channel meet the Commission's minimum spacing and coverage requirements.

(b) Station separations in licensing proceedings shall be determined by the distance between the coordinates of the proposed transmitter site in one community and

(1) The coordinates of an authorized transmitter site for the pertinent channel in the other community; or, where such transmitter site is not available for use as a reference point,

(2) The coordinates of the other community as set forth in the Index to The National Atlas of the United States of America; or if not contained therein,

(3) The coordinates of the main post office of such other community.

(4) In addition, where there are pending applications in other communities which, if granted, would have to be considered in determining station separations, the coordinates of the transmitter sites proposed in such applications must be used to determine whether the requirements with respect to minimum separations between the proposed stations in the respective cities have been met.

(c) In measuring assignment and station separations involving cities listed in the Table in combination, where there is no authorized transmitter site in any of the combination cities on the channel involved, separation measurements shall be made from the reference point which will result in the lowest separation.

(d) To calculate the distance between two reference points see paragraph (c), §73.208. However, distances shall be rounded to the nearest tenth of a kilometer.

[52 FR 11655, Apr. 10, 1987]

§73.612   Protection from interference.

(a) Permittees and licensees of TV broadcast stations are not protected from any interference which may be caused by the grant of a new station or of authority to modify the facilities of an existing station in accordance with the provisions of this subpart. The nature and extent of the protection from interference accorded to TV broadcast stations is limited solely to the protection which results from the minimum allotment and station separation requirements and the rules and regulations with respect to maximum powers and antenna heights set forth in this subpart.

(b) When the Commission determines that grant of an application would serve the public interest, convenience, and necessity and the instrument of authorization specifies an antenna location in a designated antenna farm area which results in distance separation less than those specified in this subpart, TV broadcast station permittees and licensees shall be afforded protection from interference equivalent to the protection afforded under the minimum distance separations specified in this subpart.

Note: The nature and extent of the protection from interference accorded to TV broadcast stations which were authorized prior to April 14, 1952, and which were operating on said date is limited not only as specified above but is further limited by any smaller separations existing between such stations on said date. Where, as a result of the adoption of the Table of Allotments or of changes in transmitter sites made by such stations after said date, separations smaller than the required minimum are increased but still remain lower than the required minimum, protection accorded such stations will be limited to the new separations.

[28 FR 13660, Dec. 14, 1963, as amended at 32 FR 8814, June 21, 1967; 50 FR 23698, June 5, 1985; 51 FR 44070, Dec. 8, 1986]

§73.613   Protection of Class A TV stations.

(a) An application for a new TV broadcast station or for changes in the operating facilities of an existing TV broadcast station will not be accepted for filing if it fails to comply with the requirements specified in this section.

Note to §73.613(a): Licensees and permittees of TV broadcast stations that were authorized on November 29, 1999 (and applicants for new TV stations that had been cut-off without competing applications or that were the winning bidder in a TV broadcast station auction as of that date, or that were the proposed remaining applicant in a group of mutually exclusive applications for which a settlement agreement was on file as of that date) may continue to operate with facilities that do not protect Class A TV stations. Applications filed on or before November 29, 1999 for a change in the operating facilities of such stations also are not required to protect Class A TV stations under the provisions of this section.

(b) Due to the frequency spacing which exists between TV channels 4 and 5, between channels 6 and 7, and between channels 13 and 14, first-adjacent channel protection standards shall not be applicable to these pairs of channels. Some interference protection requirements of this section only apply to stations transmitting on the UHF TV channels 14 through 51 (See §73.603(a) of this part).

(c) A UHF TV broadcast station application will not be accepted if it specifies a site less than 100 kilometers from the transmitter site of a UHF Class A TV station operating on a channel which is the seventh channel above the requested channel. Compliance with this requirement shall be determined based on a distance computation rounded to the nearest kilometer.

(d) A UHF TV broadcast station application will not be accepted if it specifies a site less than 32 kilometers from the transmitter site of a UHF Class A TV station that is authorized an effective radiated power of more than 50 kilowatts and operating on a channel which is the second, third, or fourth channel above or below the requested channel. Compliance with this requirement shall be determined based on a distance computation rounded to the nearest kilometer.

(e) In cases where a TV broadcast station has been authorized facilities that do not meet the distance separation requirements of this section, an application to modify such a station's facilities will not be accepted if it decreases that separation.

(f) New interference must not be caused to Class A TV stations authorized pursuant to Subpart J of this part, within the protected contour defined in §73.6010 of this part. For this prediction, the TV broadcast station field strength is calculated from the proposed effective radiated power and the antenna height above average terrain in pertinent directions using the methods in §73.684 of this part.

(1) For co-channel protection, the field strength is calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part.

(2) For TV broadcast stations that do not specify the same channel as the Class A TV station to be protected, the field strength is calculated using the appropriate F(50,50) chart from Figure 9, 10, or 10b of §73.699 of this part.

(g) A TV broadcast station application will not be accepted if the ratio in dB of its field strength to that of the Class A TV station at the Class A TV station's protected contour fails to meet the following:

(1) −45 dB for co-channel operations where the Class A TV station does not specify an offset carrier frequency or where the TV broadcast and Class A TV stations do not specify different offset carrier frequencies (zero, plus or minus) or −28 dB for offset carrier frequency operation where the TV broadcast and Class A TV stations specify different offset carrier frequencies.

(2) 6 dB when the protected Class A TV station operates on a VHF channel that is one channel above the requested channel.

(3) 12 dB when the protected Class A TV station operates on a VHF channel that is one channel below the requested channel.

(4) 15 dB when the protected Class A TV station operates on a UHF channel that is one channel above or below the requested channel.

(5) 23 dB when the protected Class A TV station operates on a UHF channel that is fourteen channels below the requested channel.

(6) 6 dB when the protected Class A TV station operates on a UHF channel that is fifteen channels below the requested channel.

(h) New interference must not be caused to digital Class A TV stations authorized pursuant to Subpart J of this part, within the protected contour defined in §73.6010 of this part. A TV broadcast station application will not be accepted if the ratio in dB of the field strength of the digital Class A TV station at the digital Class A TV station's protected contour to the field strength resulting from the facilities proposed in the TV broadcast station application fails to meet the D/U signal ratios for “analog TV-into-DTV” specified in §§73.623(c)(2) and 73.623(c)(3) of this part. For digital Class A TV station protection, the TV broadcast station field strength is calculated from the proposed effective radiated power and the antenna height above average terrain in pertinent directions using the methods in §73.684 of this part and using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part.

(i) In cases where a TV broadcast station has been authorized facilities that do not meet the interference protection requirements of this section, an application to modify such a station's facilities will not be accepted if it is predicted to cause new interference within the protected contour of the Class A TV or digital Class A TV station.

(j) In support of a request for waiver of the interference protection requirements of this section, an applicant for a TV broadcast station may make full use of terrain shielding and Longley-Rice terrain dependent propagation methods to demonstrate that the proposed facility would not be likely to cause interference to Class A TV stations. Guidance on using the Longely-Rice methodology is provided in OET Bulletin No. 69, which is available through the Internet at http://www.fcc.gov/oet/info/documents/bulletins/#69.

[65 FR 3001, May 10, 2000]

§73.614   Power and antenna height requirements.

(a) Minimum requirements. Applications will not be accepted for filing if they specify less than −10 dBk (100 watts) horizontally polarized visual effective radiated power in any horizontal direction. No minimum antenna height above average terrain is specified.

(b) Maximum power. Applications will not be accepted for filing if they specify a power which exceeds the maximum permitted boundaries specified in the following formulas:

(1) Channels 2-6 in Zone I:

ERPMax=102.57-33.24*Log10(HAAT)

And,

−10 dBk ≤ERPMax≤20 dBk

(2) Channels 2-6 in Zones II and III:

ERPMax=67.57-17.08* Log10 (HAAT)

And,

10 dBk ≤ERPMax≤20 dBk

(3) Channels 7-13 in Zone I:

ERPMax=107.57-33.24* Log10 (HAAT)

And,

−4.0 dBk ≤ERPMax ≤25 dBk

(4) Channels 7-13 in Zones II and III:

ERPMax=72.57-17.08* Log10 (HAAT)

And,

15 dBk ≤ERPMax≤25 dBk

(5) Channels 14-69 in Zones I, II, and III:

ERPMax=84.57-17.08* Log10 (HAAT)

And,

27 dBk ≤ERPMax≤37 dBk

Where:

ERPMax=Maximum Effective Radiated Power measured in decibels above 1 kW (dBk).

HAAT=Height Above Average Terrain measured in meters.

The boundaries specified are to be used to determine the maximum possible combination of antenna height and     ERPdBk. When specifying an ERPdBk less than that permitted by the lower boundary, any antenna HAAT can be used. Also, for values of antenna HAAT greater than 2,300 meters the maximum ERP is the lower limit specified for each equation.

(6) The effective radiated power in any horizontal or vertical direction may not exceed the maximum values permitted by this section.

(7) The effective radiated power at any angle above the horizontal shall be as low as the state of the art permits, and in the same vertical plane may not exceed the effective radiated power in either the horizontal direction or below the horizontal, whichever is greater.

(c) Determination of applicable rules. The zone in which the transmitter of a television station is located or proposed to be located determines the applicable rules with respect to maximum antenna heights and powers for VHF stations when the transmitter is located in Zone I and the channel to be employed is located in Zone II, or the transmitter is located in Zone II and the channel to be employed is located in Zone I.

[28 FR 13660, Dec. 14, 1963, as amended at 42 FR 20823, Apr. 22, 1977; 42 FR 48881, Sept. 26, 1977; 47 FR 35990, Aug. 18, 1982; 50 FR 23698, June 5, 1985; 56 FR 49707, Oct. 1, 1991; 58 FR 51250, Oct. 1, 1993]

§73.615   Administrative changes in authorizations.

In the issuance of television broadcast station authorizations, the Commission will specify the transmitter output power and effective radiated power to the nearest 0.1 dBk. Power specified by kWs shall be obtained by converting dBk to kWs to 3 significant figures. Antenna heights above average terrain will be specified to the nearest meter. Midway figures will be authorized in the lower alternative.

[50 FR 23698, June 5, 1985]

§73.616   Post-transition DTV station interference protection.

(a) Applications seeking facilities that will operate prior to the end of the DTV transition must also comply with §73.623.

(b) A petition to add a new channel to the post-transition DTV Table of Allotments contained in §73.622(i) of this subpart will not be accepted unless it meets: the DTV-to-DTV geographic spacing requirements of §73.623(d) with respect to all existing DTV allotments in the post-transition DTV Table; the principle community coverage requirements of §73.625(a); the Class A TV and digital Class A TV protection requirements in paragraph (f) of this section; the land mobile protection requirements of §73.623(e); and the FM radio protection requirement of §73.623(f).

(c) The reference coordinates of a post-transition DTV allotment shall be the authorized transmitter site, or, where such a transmitter site is not available for use as a reference point, the coordinates as designated in the FCC order creating or modifying the post-transition DTV Table of Allotments.

(d) The protected facilities of a post-transition DTV allotment shall be the facilities (effective radiated power, antenna height and antenna directional radiation pattern, if any) authorized by a construction permit or license, or, where such an authorization is not available for establishing reference facilities, the facilities designated in the FCC order creating or modifying the post-transition DTV Table of Allotments.

(e) An application will not be accepted if it is predicted to cause interference to more than an additional 0.5 percent of the population served by another post-transition DTV station. For this purpose, the population served by the station receiving additional interference does not include portions of the population within the noise-limited service contour of that station that are predicted to receive interference from the post-transition DTV allotment facilities of the applicant or portions of that population receiving masking interference from any other station.

(1) For evaluating compliance with the requirements of this paragraph, interference to populations served is to be predicted based on the 2000 census population data and otherwise according to the procedure set forth in OET Bulletin No. 69: “Longley-Rice Methodology for Evaluating TV Coverage and Interference” (February 6, 2004) (incorporated by reference, see §73.8000), including population served within service areas determined in accordance with §73.622(e), consideration of whether F(50,10) undesired signals will exceed the following desired-to-undesired (D/U) signal ratios, assumed use of a directional receiving antenna, and use of the terrain dependent Longley-Rice point-to-point propagation model. Applicants may request the use of a cell size other than the default of 2.0 km per side, but only requests for cell sizes of 1.0 km per side or 0.5 km per side will be considered. The threshold levels at which interference is considered to occur are:

(i) For co-channel stations, the D/U ratio is +15 dB. This value is only valid at locations where the signal-to-noise ratio is 28 dB or greater. At the edge of the noise-limited service area, where the signal-to-noise (S/N) ratio is 16 dB, this value is +23 dB. At locations where the S/N ratio is greater than 16 dB but less than 28 dB, D/U values are computed from the following formula:

D/U = 15+10log10[1.0/(1.0−10−x/10)]

Where x = S/N-15.19 (minimum signal to noise ratio)

(ii) For interference from a lower first-adjacent channel, the D/U ratio is −28 dB.

(iii) For interference from an upper first-adjacent channel, the D/U ratio is −26 dB.

(2) Due to the frequency spacing that exists between Channels 4 and 5, between Channels 6 and 7, and between Channels 13 and 14, the minimum adjacent channel technical criteria specified in this section shall not be applicable to these pairs of channels (see §73.603(a)).

(f) A petition to add a new channel to the post-transition DTV Table or a post-transition DTV station application that proposes to expand its allotted or authorized coverage area in any direction will not be accepted if it is predicted to cause interference to a Class A TV station or to a digital Class A TV station authorized pursuant to subpart J of this part, within the protected contour defined in §73.6010.

(1) Interference is predicted to occur if the ratio in dB of the field strength of a Class A TV station at its protected contour to the field strength resulting from the facilities proposed in the DTV application (calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699) fails to meet the D/U signal ratios for “DTV-into-analog TV” specified in §73.623(c)(2).

(2) Interference is predicted to occur if the ratio in dB of the field strength of a digital Class A TV station at its protected contour to the field strength resulting from the facilities proposed in the DTV application (calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699) fails to meet the D/U signal ratios specified in paragraph (e) of this section.

(3) In support of a request for waiver of the interference protection requirements of this section, an applicant for a post-transition DTV broadcast station may make full use of terrain shielding and Longley-Rice terrain dependent propagation methods to demonstrate that the proposed facility would not be likely to cause interference to Class A TV stations. Guidance on using the Longley-Rice methodology is provided in OET Bulletin No. 69, which is available through the Internet at http://www.fcc.gov/oet/info/documents/bulletins/#69.

Note to §73.616: When this rule was adopted, the filing freeze announced in an August 2004 public notice (19 FCC Rcd 14810 (MB 2004)) remained in effect. For a short period of time after the filing freeze is lifted, until a date to be announced by a Media Bureau public notice, applicants must protect Appendix B facilities in addition to any authorized facilities required to be protected pursuant to this rule section.

[73 FR 5682, Jan. 30, 2008]

§73.621   Noncommercial educational TV stations.

In addition to the other provisions of this subpart, the following shall be applicable to noncommercial educational television broadcast stations:

(a) Except as provided in paragraph (b) of this section, noncommercial educational broadcast stations will be licensed only to nonprofit educational organizations upon a showing that the proposed stations will be used primarily to serve the educational needs of the community; for the advancement of educational programs; and to furnish a nonprofit and noncommercial television broadcast service.

(1) In determining the eligibility of publicly supported educational organizations, the accreditation of their respective state departments of education shall be taken into consideration.

(2) In determining the eligibility of privately controlled educational organizations, the accreditation of state departments of education or recognized regional and national educational accrediting organizations shall be taken into consideration.

(b) Where a municipality or other political subdivision has no independently constituted educational organization such as, for example, a board of education having autonomy with respect to carrying out the municipality's educational program, such municipality shall be eligible for a noncommercial educational television broadcast station. In such circumstances, a full and detailed showing must be made that a grant of the application will be consistent with the intent and purpose of the Commission's rules and regulations relating to such stations.

(c) Noncommercial educational television broadcast stations may transmit educational, cultural and entertainment programs, and programs designed for use by schools and school systems in connection with regular school courses, as well as routine and administrative material pertaining thereto.

(d) A noncommercial educational television station may broadcast programs produced by or at the expense of, or furnished by persons other than the licensee, if no other consideration than the furnishing of the program and the costs incidental to its production and broadcast are received by the licensee. The payment of line charges by another station, network, or someone other than the licensee of a noncommercial educational television station, or general contributions to the operating costs of a station, shall not be considered as being prohibited by this paragraph.

(e) Each station shall furnish a nonprofit and noncommercial broadcast service. Noncommercial educational television stations shall be subject to the provisions of §73.1212 to the extent that they are applicable to the broadcast of programs produced by, or at the expense of, or furnished by others. No promotional announcements on behalf of for profit entities shall be broadcast at any time in exchange for the receipt, in whole or in part, of consideration to the licensee, its principals, or employees. However, acknowledgements of contributions can be made. The scheduling of any announcements and acknowledgements may not interrupt regular programming.

Note: Commission interpretation of this rule, including the acceptable form of acknowledgements, may be found in the Second Report and Order in Docket No. 21136 (Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations), 86 F.C.C. 2d 141 (1981); the Memorandum Opinion and Order in Docket No. 21136, 90 FCC 2d 895 (1982), and the Memorandum Opinion and Order in Docket 21136, 49 FR 13534, April 5, 1984.

(f) Telecommunications Service on the Vertical Blanking Interval and in the Visual Signal. The provisions governing VBI and visual signal telecommunications service in §73.646 are applicable to noncommercial educational TV stations.

(g) Non-program related data signals transmitted on Line 21 pursuant to §73.682(a)(22)(ii) may be used for remunerative purposes.

(h) Mutually exclusive applications for noncommercial educational TV stations operating on reserved channels shall be resolved pursuant to the point system in subpart K.

(i) With respect to the provision of advanced television services, the requirements of this section will apply to the entire digital bitstream of noncommercial educational television stations, including the provision of ancillary or supplementary services.

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 7558, May 15, 1970; 47 FR 36179, Aug. 19, 1982; 48 FR 27068, June 13, 1983; 49 FR 29069, July 18, 1984; 50 FR 4664, Feb. 1, 1985; 50 FR 4684, Feb. 1, 1985; 61 FR 36304, July 10, 1996; 65 FR 36378, June 8, 2000; 66 FR 58982, Nov. 26, 2001]

§73.622   Digital television table of allotments.

(a) General. The following table of allotments contains the digital television (DTV) channel allotments designated for the listed communities in the United States, its Territories, and possessions. The initial DTV Table of Allotments was established on April 3, 1997, to provide a second channel for DTV service for all eligible analog television broadcasters. Requests for addition of new DTV allotments, or requests to change the channels allotted to a community must be made in a petition for rule making to amend the DTV Table of Allotments. A request to amend the DTV table to change the channel of an allotment in the DTV table will be evaluated for technical acceptability using engineering criteria set forth in §73.623(c). A request to amend the DTV table to add a new allotment will be evaluated for technical acceptability using the geographic spacing criteria set forth in §73.623(d). DTV allotments designated with an asterisk are assigned for use by non-commercial educational broadcast stations only. Stations operating on DTV allotments designated with a “c” are required to comply with paragraph (g) of this section. Rules governing noncommercial educational TV stations are contained in §73.621. Where there is only one technically available channel available in a community, an entity that would be eligible to operate a noncommercial educational broadcast station may, prior to application, initiate a rulemaking proceeding requesting that an unoccupied or new channel in the community be changed or added as reserved only for noncommercial educational broadcasting upon demonstrating that the noncommercial educational proponent would provide a first or second noncommercial educational TV service to 2,000 or more people who constitute 10% of the population within the proposed allocation's noise limited contour.

(1) Petitions requesting the addition of a new allotment must specify a channel in the range of channels 2-51.

(2) Petitions requesting a change in the channel of an initial allotment must specify a channel in the range of channels 2-58.

(b) DTV Table of Allotments.

Alabama

CommunityChannel No.
Anniston9
Bessemer18c
Birmingham30, 36, 50, 52, *53
Demopolis*19
Dothan21, 36
Dozier*11
Florence14, 20, *22
Gadsden26, 45c
Homewood28
Huntsville*24, 32c, 41, 49c, 59
Louisville*44c
Mobile9, 18, 20, 27, *41, 47
Montgomery14, 16, *27, 46c, 51
Mount Cheaha*56
Opelika31
Ozark33
Selma55
Troy48
Tuscaloosa5
Tuskegee24

Alaska

CommunityChannel No.
Anchorage6c, *8c, 10c, 12c, 20, *26, 28, 32
Bethel*3
Dillingham*9
Fairbanks18, 22, *24, 26, 28
Juneau*10, 11
Ketchikan*8, 13
North Pole20
Sitka2

Arizona

CommunityChannel No.
Flagstaff18, 22, 27, 32
Green Valley47c
Kingman19, *46
Mesa36
Phoenix17, 20, 24, 26, *29, 31, 34c, 49, 56
Prescott25
Sierra Vista44
Tolleson52c
Tucson19c, 23, 25, *28c, *30, 32, 35, 42
Yuma16, 41

Arkansas

CommunityChannel No.
Arkadelphia*13
El Dorado*12, 27
Fayetteville*9, 15
Fort Smith18, 21, 27
Hot Springs14
Jonesboro9c, *20c, 49c
Little Rock*5, 12c, 22, 30, 32, 44
Mountain View*13
Newark*27
Pine Bluff24, 39c
Rogers50
Springdale39

California

CommunityChannel No.
Anaheim32
Arcata22
Avalon47c
Bakersfield10, 25, 33, 55
Barstow44
Blythe*4
Calipatria50
Ceres*15c
Chico36, 43
Clovis44c
Coalinga*22
Concord63c
Corona39
Cotati*23c
El Centro22, 48
Eureka*11, 16, 17, 28
Fort Bragg15
Fresno7, 9, 34, 38, *40
Hanford20
Huntington Beach*48
Long Beach61c
Los Angeles31c, 35c, 36, *41c, 42, 43, 53c, *59c, 60, 65c, 66
Merced5
Modesto18
Monterey31, 32
Novato47
Oakland56
Ontario29c
Oxnard24
Palm Springs46, 52
Paradise20
Porterville48
Rancho Palos Verdes51c
Redding*18, 34
Riverside68
Sacramento21, 35, *43, 48, *53, 55, 61
Salinas10, 13
San Bernardino*26, 38
San Diego18, 19, 25, *30, 40c, 55
San Francisco19, 24, 27c, 29, *30, *33c, 39c, 45c, 51, 57
San Jose12c, 41, 49c, *50, 52
San Luis Obispo15, 34c
San Mateo*43
Sanger36
Santa Ana23c
Santa Barbara21, 27
Santa Maria19
Santa Rosa54
Stockton25, 46, 62
Twentynine Palms23
Vallejo34
Ventura49
Visalia28, *50c
Watsonville*58

Colorado

CommunityChannel No.
Boulder15c
Broomfield*38
Castle Rock45
Colorado Springs10, 22c, 24
Craig*48
Denver16, 17, *18, 19, 32c, 34, 35, *40, 43, 51c
Durango15
Fort Collins21
Glenwood Springs23, *39
Grand Junction2, 7, 12c, 15, *17
Greeley45
La Junta*30
Lamar*50
Leadville*49
Longmont29
Montrose13
Pueblo*26, 42
Steamboat Springs10
Sterling23

Connecticut

CommunityChannel No.
Bridgeport42, *52
Hartford31, *32, 33, 46
New Britain35
New Haven6, 10, *39
New London34
Norwich*45
Waterbury12

Delaware

CommunityChannel No.
Seaford*44
Wilmington31, *55

District of Columbia

CommunityChannel No.
Washington*27c, *33c, 34, 35, 36, 39, 48, 51c

Florida

CommunityChannel No.
Apalachicola3
Boca Raton*40
Bradenton*5, 42
Cape Coral35
Clearwater21
Clermont17
Cocoa*30, 53c
Daytona Beach11, 49
Fort Lauderdale52c
Fort Myers9, 15, *31c
Fort Pierce*38, 50
Fort Walton Beach40, 49, 50
Gainesville16, *36
High Springs28
Hollywood47
Jacksonville13c, 19, 32, 34, *38, 42, *44
Key West3, 12
Lake Worth36
Lakeland19
Leesburg40, *46c
Live Oak48
Marathon*34
Melbourne20, 48
Miami8c, 9, *18c, 19, *20, 22, 24c, 26, 31, 32, 46c
Naples41, 45
New Smyrna Beach*33
Ocala31
Orange Park10
Orlando14, 22, *23, 39, 41, 58
Palm Beach49
Panama City8, 9, 19, *38
Panama City Beach47c
Pensacola17, *31, 34c, 45c
Sarasota52
St. Petersburg24, 57, 59
Tallahassee2, 22, *32
Tampa7, 12, 29c, *34, 47, *54
Tequesta16
Tice33
Venice25
West Palm Beach13c, *27, 28, 55

Georgia

CommunityChannel No.
Albany12, 17
Athens*12c, 48
Atlanta10, 19, 20, *21, 25, 27, 39, *41, 43
Augusta30, 31, 42, 51
Bainbridge50c
Baxley35c
Brunswick24
Chatsworth*33
Cochran*7
Columbus15, *23, 35, 47, 9
Cordele51
Dalton16
Dawson*8
Macon4, 16, 40, 45
Monroe44
Pelham*5
Perry32
Rome51
Savannah*13, 15, 23c, 39
Thomasville46
Toccoa24
Valdosta43
Waycross*9c
Wrens*2

Hawaii

CommunityChannel No.
Hilo8, 18, *19, 21, 22, 23, *31, *39c
Honolulu8, *10c, *18, 19, 22, 23, 27c, 31, 33c, 35, 40, *43
Kailua Kona25
Kaneohe41
Lihue*7, *12, *28c, *45
Wailuku16c, 24, *28c, 29, *30, *34c, 36, 45

Idaho

CommunityChannel No.
Boise*21, 26, 28
Burley*48
Caldwell10c
Coeur D'alene*45
Filer*18
Idaho Falls9c, 36
Lewiston32
Moscow*12
Nampa13c, 24
Pocatello*17, 23
Twin Falls16, *22, 34
Weiser*34

Illinois

CommunityChannel No.
Aurora59
Bloomington28
Carbondale*40
Champaign41, 48
Charleston*50
Chicago3c, 19, *21c, 27c, 29, 31, 43, 45c, *47, 52
Decatur18c, 22
East St. Louis47c
Freeport41
Harrisburg34
Jacksonville*15c
Joliet53
Lasalle10
Macomb*21
Marion17
Moline*23, 38
Mount Vernon21
Olney*19
Peoria30, 39, 40, *46, 57
Quincy32, *34, 54
Rock Island58
Rockford16, 42, 54
Springfield36, 42, 44, 53
Urbana*9, 26

Indiana

CommunityChannel No.
Angola12
Bloomington*14, 27, 48, 56
Elkhart58
Evansville*12, 28, 45c, 46, 59
Fort Wayne19, 24, 31, 36, *40c
Gary*17, 51c
Hammond36
Indianapolis9c, 16, *21c, 25, *44, 45, 46
Kokomo54
Lafayette11
Marion32
Muncie52
Richmond39
Salem51
South Bend30, *35c, 42, 48
Terre Haute24, 36, 39c
Vincennes*52

Iowa

CommunityChannel No.
Ames59
Burlington41
Cedar Rapids27, 47, 51, 52
Centerville*44
Council Bluffs*33c
Davenport*34, 49, 56
Des Moines16, 19, 26, 31, *50, 56
Dubuque43
Fort Dodge*25
Iowa City25, *45
Mason City*18, 42
Ottumwa14
Red Oak*35
Sioux City*28c, 30, 39, 41, 49
Waterloo*35, 55

Kansas

CommunityChannel No.
Colby17, *19
Derby46
Ensign5
Fort Scott40
Garden City16, 18, *42
Goodland14
Great Bend22
Hays*16, 20
Hutchinson19, *29, 35
Lakin*8
Lawrence36
Oakley*40
Pittsburg13
Salina17
Topeka*23, 28c, 44, 48
Wichita21, 26, 31, 45

Kentucky

CommunityChannel No.
Ashland*26c, 44
Beattyville7
Bowling Green16, *18, 33, *48
Campbellsville19
Covington*24
Danville4
Elizabethtown*43
Harlan51
Hazard12, *16
Lexington13, 39, 40, *42
Louisville8, *17, 26, *38, 47, 49, 55
Madisonville20c, *42
Morehead*15, 21
Murray*36
Newport29
Owensboro30
Owenton*44
Paducah32, 41, 50c
Pikeville*24
Somerset*14

Louisiana

CommunityChannel No.
Alexandria*26c, 32c, 35
Baton Rouge13, *25, 34c, 45c, 46
Columbia57
Hammond42
Lafayette16c, *23, 28, 56
Lake Charles8c,*20, 30c
Monroe7, *19
New Orleans*11, 15, 21c, 29, *31, 36, 40, 43, 50c
Shreveport17, *25c, 28, 34c, 44
Slidell24
West Monroe36, 38

Maine

CommunityChannel No.
Augusta*17
Bangor14, 19, 25
Biddeford*45
Calais*10
Lewiston28
Orono*9
Poland Spring46
Portland38, 43, 44
Presque Isle16, *20

Maryland

CommunityChannel No.
Annapolis*42
Baltimore*29, 38, 40, 41, 46c, 52, 59
Frederick*28
Hagerstown16, *44, 55
Oakland*54
Salisbury21, 53, *56

Massachusetts

CommunityChannel No.
Adams36
Boston*19, 20, 30, 31, 32, 39c, 42, *43
Cambridge41
Lawrence18
Marlborough23
New Bedford22, 49
Norwell52
Springfield11, 55, *58c
Vineyard Haven40
Worcester29, *47

Michigan

CommunityChannel No.
Alpena13, *57
Ann Arbor33
Bad Axe*15
Battle Creek20, 44c
Bay City22
Cadillac*17, 40, 47
Calumet11
Cheboygan35
Detroit14, 21c, 41, *43, 44, 45, 58
East Lansing*55
Escanaba48
Flint16, 36, *52
Grand Rapids7, *11, 19, 39
Iron Mountain22
Jackson34
Kalamazoo2, *5, 45
Lansing38, 51, 59
Manistee*58
Marquette*33, 3
Mount Clemens39c
Mount Pleasant*56
Muskegon24
Onondaga57
Saginaw30, 48
Sault Ste. Marie9c, 49
Traverse City*23, 31, 50
University Center*18
Vanderbilt59

Minnesota

CommunityChannel No.
Alexandria24, 36
Appleton*31
Austin*20, 33
Bemidji*18
Brainerd*28
Crookston*16
Duluth17, 33, *38, 43
Hibbing*31, 36, *51
Mankato38
Minneapolis21, 22, *26, 32, 35, *44
Redwood Falls27
Rochester36, 46
St. Cloud40
St. Paul*16, *34, 50
Thief River Falls32
Walker20
Worthington*15

Mississippi

CommunityChannel No.
Biloxi*16, 39
Booneville*55
Bude*18c
Columbus35
Greenville17
Greenwood*25, 32
Gulfport48
Hattiesburg58
Holly Springs41c
Jackson9, *20, 21, 41c, 52
Laurel28
Meridian26, 31c, *44, 49
Mississippi State*10
Natchez49c
Oxford*36
Tupelo57
West Point16

Missouri

CommunityChannel No.
Birch Tree*7
Bowling Green*50
Cape Girardeau22, 57
Columbia22, 36
Hannibal29
Jefferson City12, 20
Joplin*25, 43, 46
Kansas City7, *18, 24, 31, 34, 42c, 47, 51c
Kirksville33
Poplar Bluff18
Sedalia15
Springfield19, *23, 28c, 44, 52
St. Joseph21, 53
St. Louis14, 26, 31c, 35, *39, 43, 56

Montana

CommunityChannel No.
Billings10, 11, *16, 18
Bozeman*8, 13
Butte5, 19c, 33
Glendive10
Great Falls7, 8, *21, 45
Hardin22
Helena14, 29
Kalispell38, *46
Miles City13, *39
Missoula7, *27, 36, 40

Nebraska

CommunityChannel No.
Albion23
Alliance*24
Bassett*15
Grand Island19, 32
Hastings21, *28
Hayes Center18
Kearney36
Lexington*26
Lincoln25, 31, *40
McCook12
Merriman*17
Norfolk*16
North Platte*16, 22
Omaha*17, 20, 22, 38, 43c, 45
Scottsbluff7, 29
Superior34

Nevada

CommunityChannel No.
Elko8, *15
Henderson9
Las Vegas2, 7, *11c, 12, 16c, 22c, 29
Laughlin32
Paradise40c
Reno7, 9c, 13, *15, 20, 22c, 26, 44
Winnemucca12

New Hampshire

CommunityChannel No.
Berlin*15
Concord33
Derry35
Durham*57
Keene*49
Littleton*48
Manchester59
Merrimack34

New Jersey

CommunityChannel No.
Atlantic City44, 49
Burlington27
Camden*22
Linden36
Montclair*51c
New Brunswick*18
Newark53c, 61
Newton8c
Paterson40
Secaucus38
Trenton*43
Vineland66c
West Milford*29
Wildwood36

New Mexico

CommunityChannel No.
Albuquerque16, *17, 21, 24c, 26, *35, 42c, 45
Carlsbad19
Clovis20
Farmington8, 17
Hobbs16, *47
Las Cruces*23c, 47
Portales*32
Roswell28c, *31, 38, 41
Santa Fe10, 27, 29
Silver City12, *33
Socorro*31

New York

CommunityChannel No.
Albany7, 12, 26
Amsterdam50
Batavia53
Binghamton4, 7, 8, *42
Buffalo14, *32, 33, 34, 38, 39, *43
Carthage35
Corning50
Elmira2, 55
Garden City*22c
Jamestown27c
Kingston48
New York*24, 28, 30, 33, 44, 45, 56
North Pole14
Norwood*23
Plattsburgh*38
Poughkeepsie27
Riverhead57
Rochester*16, 28, 45, 58, 59
Schenectady*34, 39, 43
Smithtown23
Springville46
Syracuse17, 19, *25c, 44c, 47, 54
Utica27, 29, 30
Watertown21, *41

North Carolina

CommunityChannel No.
Asheville*25, 45, 56, 57
Belmont47c
Burlington14
Chapel Hill*59
Charlotte*11, 22, 23, 27, 34
Concord*44
Durham27, 52
Edenton*20
Fayetteville36, 38
Goldsboro55
Greensboro33, 43, 51
Greenville10c, 21, *23
Hickory40
High Point35
Jacksonville*18, 34
Kannapolis50
Lexington19
Linville*54
Lumberton*25
Morehead City24
New Bern48
Raleigh49, 53, 57
Roanoke Rapids*39
Rocky Mount15
Washington32
Wilmington*29, 30, 44, 46
Wilson42
Winston-Salem29, 31, *32

North Dakota

CommunityChannel No.
Bismarck16, *22, 23, 31
Devils Lake*25, 59
Dickinson18, 19, *20
Ellendale*20c
Fargo19, 21, *23, 44
Grand Forks*56
Jamestown18
Minot15c, *40, 45, 58
Pembina15
Valley City38
Williston14, *51, 52

Ohio

CommunityChannel No.
Akron30, *50c, 59
Alliance*46c
Athens*27
Bowling Green*56
Cambridge*35
Canton39, 47
Chillicothe46
Cincinnati10c, 31, 33, *34, 35
Cleveland2, 15, *26c, 31, 34
Columbus13, 14, 21, 36, *38
Dayton30, 41, 50, 51, *58
Lima8, 47
Lorain28
Mansfield12
Newark24
Oxford*28
Portsmouth17, *43c
Sandusky42
Shaker Heights10
Springfield18
Steubenville57
Toledo5, 17, 19, *29, 46, 49
Youngstown20, 36, 41
Zanesville40

Oklahoma

CommunityChannel No.
Ada26
Bartlesville15
Cheyenne*8
Claremore*36c
Enid18
Eufaula*31
Guymon*29
Lawton11
Oklahoma City7, 15c, 24, 27, *32, 33, 39, 40, 50, 51
Okmulgee28
Shawnee29
Tulsa10, 22, *26, *38, 42c, 48c, 49, 55, 56

Oregon

CommunityChannel No.
Bend*11, 18
Coos Bay21, 22
Corvallis*39
Eugene17c, 25, *29c, 31, 44
Klamath Falls13, 29, *33,
La Grande*5
Medford15, 27c, 35, 38, *42
Pendleton8
Portland*27, 30, 40, 43, 45, 6
Roseburg18, 19, 45
Salem4, 33c

Pennsylvania

CommunityChannel No.
Allentown46, *62
Altoona24c, 32, 46
Bethlehem9
Clearfield*15
Erie16, 22, *50, 52, 58
Greensburg50
Harrisburg4, 10, *36
Hazleton45c
Jeannette49
Johnstown29, 34
Lancaster23, 58
Philadelphia26, 32, *34, 42, 54, 64, 67
Pittsburgh25, 26, *38, 42, 43, 48, 51
Reading25
Red Lion30
Scranton13, 31, 32, *41, 49
Wilkes-Barre11
Williamsport29
York47

Rhode Island

CommunityChannel No.
Block Island17
Providence13c, *21, 51, 54c

South Carolina

CommunityChannel No.
Allendale*33
Anderson14
Beaufort*44
Charleston34, 35, 40, 47, *49, 50
Columbia8, 17, *32, 41, 48
Conway*9
Florence16c, 20, *45, 56
Georgetown*38
Greenville*9, 35, 57, 59
Greenwood*18
Hardeeville27
Myrtle Beach18
Rock Hill15, 39
Spartanburg43, 53
Sumter*28c, 39

South Dakota

CommunityChannel No.
Aberdeen*17c, 28
Brookings*18
Eagle Butte*25
Florence2
Huron22
Lead10, 29
Lowry*15
Martin*23
Mitchell26
Pierre19, *21
Rapid City2, 16c, 18, *26
Reliance13
Sioux Falls7, *24c, 29, 32, 47c, 51
Vermillion*34

Tennessee

CommunityChannel No.
Chattanooga13, *29, 35, 40, 47
Cleveland42
Cookeville36, *52
Crossville50
Greeneville38
Hendersonville51c
Jackson39, 43
Jellico23
Johnson City58
Kingsport27
Knoxville7, *17, 26, 30, 31, 34
Lebanon44
Lexington*47
Memphis25c, 28, *29, 31c, 51c, 52, 53
Murfreesboro38
Nashville10, 15, 21, 23, 27, *46, 56
Sneedville*41

Texas

CommunityChannel No.
Abilene24, 29
Alvin36
Amarillo*8c, 9, 15c, 19, 23
Arlington42
Austin21, *22, 33, 43c, 49, 56
Baytown41
Beaumont21, *33, 50
Belton38
Big Spring33
Brownsville24c
Bryan29c, 50
College Station*12
Conroe5, 42
Corpus Christi8, 13, 18, *23, 27
Dallas9c, *14, 32, 35, 36, 40c, 45
Decatur30c
Del Rio28
Denton*43
Eagle Pass18
El Paso15c, 16, 17, 18, 25, *30, *39c, 51
Fort Worth18, 19, 41, 51
Galveston*23c, 48c
Garland24c
Greenville46
Harlingen31, *34, 38
Houston*9c, 19, *24, 27c, 31, 32, 35, 38, 44
Irving48
Jacksonville22
Katy52c
Kerrville32
Killeen13
Lake Dallas54
Laredo15, 19, 31
Llano27
Longview31
Lubbock9, 25, 27, 35c, *39, 40
Lufkin11
McAllen49
Midland26
Nacogdoches18
Odessa13, 23, 31, *38, 43c
Port Arthur40
Rio Grande City20
Rosenberg46c
San Angelo11, 16, 19
San Antonio*8, *16, 30c, 38, 39, 48, 55, 58
Sherman20
Snyder10
Sweetwater20
Temple9
Texarkana15, *50
Tyler10
Victoria11, 15
Waco*20, 26c, 53, 57
Weslaco13
Wichita Falls15, 22, 28

Utah

CommunityChannel No.
Cedar City14, 44
Monticello*41
Ogden29, *34
Provo17c, *39
Salt Lake City27, 28, 35, 38, 40, *42
St. George9

Vermont

CommunityChannel No.
Burlington13, *32, 43, 53
Hartford25
Rutland*9
St. Johnsbury*18
Windsor*24

Virginia

CommunityChannel No.
Arlington15c
Ashland47
Bristol28
Charlottesville32, *46
Danville41
Fairfax*57c
Front Royal*21
Goldvein*30
Grundy49
Hampton41
Hampton-Norfolk*16c
Harrisonburg49
Lynchburg20, 34
Manassas43c
Marion*42
Norfolk38, 40, 46,
Norton*32
Petersburg22
Portsmouth31, 50
Richmond*24c, 25, 26, *42, *44, 54
Roanoke*3, 17, 18, 30, 36
Staunton*11
Virginia Beach29

Washington

CommunityChannel No.
Bellevue32, 50
Bellingham19, 35
Centralia*19
Everett31
Kennewick44
Medical Lake51
Pasco18
Pullman*17
Richland26c, *38
Seattle25, 38, 39, *41, 44, 48
Spokane*8, 13, 15, 20, 30, 36
Tacoma14, 18, *27, 36, *42
Vancouver48
Wenatchee46
Yakima14, 16, *21, 33

West Virginia

CommunityChannel No.
Bluefield14, 46
Charleston19, 39, 41, 52
Clarksburg10, 52
Grandview*53
Huntington23, *34c, 47
Lewisburg8
Martinsburg12
Morgantown*33
Oak Hill50
Parkersburg49
Weston6
Wheeling32

Wisconsin

CommunityChannel No.
Appleton27c
Chippewa Falls49c
Eagle River28
Eau Claire15, 39
Fond Du Lac44
Green Bay23, 39c, 41, *42, 51
Janesville32
Kenosha40
La Crosse14, 17, *30, 41
Madison11, 19, *20, 26, 50
Manitowoc19
Mayville43
Menomonie*27
Milwaukee*8, 22, 25c, 28, 33, 34, *35, 46, 61
Park Falls*47
Racine48
Rhinelander16
Superior19
Suring21
Wausau*24, 29, 40

Wyoming

CommunityChannel No.
Casper15c, 17, 18
Cheyenne11, 28c, 30
Jackson4
Lander7, *8
Rawlins9
Riverton16
Rock Springs21
Sheridan13

Guam

CommunityChannel No.
Agana2, 4, 5
Tamuning17

Puerto Rico

CommunityChannel No.
Aguada62
Aguadilla17c, *34, 69
Arecibo53, 61c
Bayamon59c
Caguas56, *57
Carolina51
Fajardo*16, 33
Guayama45
Humacao49
Mayaguez23c, 29, 35, 63
Naranjito65c
Ponce8c, 15c, 19, *25, 43c, 47
San Juan21, 27c, 28, 31c, 32, *55c
San Sebastian39c
Yauco41c

Virgin Islands

CommunityChannel No.
Charlotte Amalie*44, 48, 50
Christiansted20, 23

(c)(1) Availability of channels. Applications may be filed to construct DTV broadcast stations only on the channels designated in the DTV Table of Allotments set forth in paragraph (b) of this section, and only in the communities listed therein. Applications that fail to comply with this requirement, whether or not accompanied by a petition to amend the DTV Table, will not be accepted for filing. However, applications specifying channels that accord with publicly announced FCC Orders changing the DTV Table of Allotments will be accepted for filing even if such applications are tendered before the effective dates of such channel change. An application for authority to construct a DTV station on an allotment in the initial DTV table may only be filed by the licensee or permittee of the analog TV station with which that initial allotment is paired, as set forth in Appendix B of the Memorandum Opinion and Order on Reconsideration of the Sixth Report and Order in MM Docket 87-268, FCC 98-24 (Memorandum Opinion and Order) adopted January 29, 1998. Copies of the Memorandum Opinion and Order may be inspected during normal business hours at the: Federal Communications Commission, Room CY-C203, 445 12th Street, SW., Reference Information Center, Washington, DC, 20554. This document is also available through the Internet on the FCC Home Page at http://www.fcc.gov. Applications may also be filed to implement an exchange of channel allotments between two or more licensees or permittees of analog TV stations in the same community, the same market, or in adjacent markets provided, however, that the other requirements of this section and §73.623 are met with respect to each such application.

(2) Notwithstanding paragraph (c)(1) of this section, an application may be filed for a channel or community not listed in the DTV Table of Allotments if it is consistent with the rules and policies established in the Third Report and Order in WT Docket 99-168 (FCC 01-25), adopted January 18, 2001. Where such a request is approved, the Media Bureau will change the DTV Table of Allotments to reflect that approval.

(d) Reference points and distance computations. (1) The reference coordinates of a DTV allotment included in the initial DTV Table of Allotments are the coordinates of the authorized transmitting antenna site of the associated analog TV station, as set forth in Appendix B of the Memorandum Opinion and Order (referenced above). An application for authority to construct or modify DTV facilities on such an allotment may specify an alternate location for the DTV transmitting antenna that is within 5 kilometers of the DTV allotment reference coordinates without consideration of electromagnetic interference to other DTV or analog TV broadcast stations, allotments or applications, provided the application complies with paragraph (f)(2) of this section. Location of the transmitting antenna of such a station at a site more than 5 kilometers from the DTV allotment reference coordinates must comply with the provisions of section 73.623(c). In the case where a DTV station has been granted authority to construct more than 5 kilometers from its reference coordinates pursuant to section 73.623(c), and its authorized coverage area extends in any azimuthal direction beyond the DTV coverage area determined for the DTV allotment reference facilities, then the coordinates of such authorized site are to be used in addition to the coordinates of the DTV allotment to determine protection from new DTV allotments pursuant to §73.623(d) and from subsequent DTV applications filed pursuant to §73.623(c).

(2) The reference coordinates of a DTV allotment not included in the initial DTV Table of Allotments shall be the authorized transmitter site, or, where such a transmitter site is not available for use as a reference point, the coordinates as designated in the FCC order modifying the DTV Table of Allotments.

(e) DTV Service Areas. (1) The service area of a DTV station is the geographic area within the station's noise-limited F(50,90) contour where its signal strength is predicted to exceed the noise-limited service level. The noise-limited contour is the area in which the predicted F(50,90) field strength of the station's signal, in dB above 1 microvolt per meter (dBu) as determined using the method in section 73.625(b) exceeds the following levels (these are the levels at which reception of DTV service is limited by noise):

  dBu
Channels 2-628
Channels 7-1336
Channels 14-6941

(2) Within this contour, service is considered available at locations where the station's signal strength, as predicted using the terrain dependent Longley-Rice point-to-point propagation model, exceeds the levels above. Guidance for evaluating coverage areas using the Longley-Rice methodology is provided in OET Bulletin No. 69. Copies of OET Bulletin No. 69 may be inspected during normal business hours at the Federal Communications Commission, 445 12th Street, S.W, Dockets Branch (Room CY A09257), Washington, DC 20554. This document is also available through the Internet on the FCC Home Page at http://www.fcc.gov.

Note to paragraph (e)(2): During the transition, in cases where the assigned power of a UHF DTV station in the initial DTV Table is 1000 kW, the Grade B contour of the associated analog television station, as authorized on April 3, 1997, shall be used instead of the noise-limited contour of the DTV station in determining the DTV station's service area. In such cases, the DTV service area is the geographic area within the station's analog Grade B contour where its DTV signal strength is predicted to exceed the noise-limited service level, i.e., 41 dB, as determined using the Longley-Rice methodology.

(3) For purposes of determining whether interference is caused to a DTV station's service area, the maximum technical facilities, i.e., antenna height above average terrain (antenna HAAT) and effective radiated power (ERP), specified for the station's allotment are to be used in determining its service area.

(f) DTV maximum power and antenna heights. (1) The maximum, or reference, effective radiated power (ERP) and antenna height above average terrain (antenna HAAT) for an allotment included in the initial DTV Table of Allotments are set forth in Appendix B of the Memorandum Opinion and Order (referenced in paragraph (c) of this section). In each azimuthal direction, the reference ERP value is based on the antenna HAAT of the corresponding analog TV station and achieving predicted coverage equal to that analog TV station's predicted Grade B contour, as defined in section 73.683.

(2) An application for authority to construct or modify DTV facilities will not be subject to further consideration of electromagnetic interference to other DTV or analog TV broadcast stations, allotments or applications, provided that:

(i) The proposed ERP in each azimuthal direction is equal to or less than the reference ERP in that direction; and

(ii) The proposed antenna HAAT is equal to or less than the reference antenna HAAT or the proposed antenna HAAT exceeds the reference antenna HAAT by 10 meters or less and the reference ERP in paragraph (f)(2)(i) of this section is adjusted in accordance with paragraph (f)(3) of this section; and

(iii) The application complies with the location provisions in paragraph (d)(1) of this section.

(3)(i) A DTV station may increase its antenna HAAT by up to 10 meters from that specified in Appendix B if it reduces its DTV power to a level at or below the level of adjusted DTV power computed in the following formula:

ERP adjustment in dB = 20log(H1/H2)

Where H1 = Reference antenna HAAT specified in the DTV Table, and H2 = Actual antenna HAAT

(ii) Alternatively, a DTV application that specifies an antenna HAAT within 25 meters below that specified in Appendix B may adjust its power upward to a level at or below the adjusted DTV power in accordance with the formula in paragraph (f)(3)(i) of this section without an interference showing. For a proposed antenna more than 25 meters below the reference antenna HAAT, the DTV station may increase its ERP up to the level permitted for operation with an antenna that is 25 meters below the station's reference antenna HAAT.

(4) UHF DTV stations may request an increase in power, up to a maximum of 1000 kW ERP, to enhance service within their authorized service area.

(5) Licensees and permittees assigned a DTV channel in the initial DTV Table of Allotments may request an increase in either ERP in some azimuthal direction or antenna HAAT, or both, that exceed the initial technical facilities specified for the allotment in Appendix B of the Memorandum Opinion and Order (referenced in paragraph (c) of this section), up to the maximum permissible limits on DTV power and antenna height set forth in paragraph (f)(6), (f)(7), or (f)(8) of this section, as appropriate, or up to that needed to provide the same geographic coverage area as the largest station within their market, whichever would allow the largest service area. Such requests must be accompanied by a technical showing that the increase complies with the technical criteria in §73.623(c), and thereby will not result in new interference exceeding the de minimis standard set forth in that section, or statements agreeing to the change from any co-channel or adjacent channel stations that might be affected by potential new interference, in accordance with §73.623(f). In the case where a DTV station has been granted authority to construct pursuant to §73.623(c), and its authorized coverage area extends in any azimuthal direction beyond the DTV coverage area determined for the DTV allotment reference facilities, then the authorized DTV facilities are to be used in addition to the assumed facilities of the initial DTV allotment to determine protection from new DTV allotments pursuant to §73.623(d) and from subsequent DTV applications filed pursuant to §73.623(c). The provisions of this paragraph regarding increases in the ERP or antenna height of DTV stations on channels in the initial DTV Table of Allotments shall also apply in cases where the licensee or permittee seeks to change the station's channel as well as alter its ERP and antenna HAAT. Licensees and permittees are advised that where a channel change is requested, it may, in fact, be necessary in specific cases for the station to operate with reduced power, a lower antenna, or a directional antenna to avoid causing new interference to another station.

(6) A DTV station that operates on a channel 2-6 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 10 kW if its antenna HAAT is at or below 305 meters and it is located in Zone I or a maximum ERP of 45 kW if its antenna HAAT is at or below 305 meters and it is located in Zone II or Zone III. A DTV station that operates on a channel 2-6 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operate with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

Maximum Allowable ERP and Antenna Height for DTV Stations In Zones II or III on Channels 2-6

Antenna HAAT (meters)ERP (kW)
61010
58011
55012
52014
49016
46019
42522
39526
36531
33537
30545

(ii) For DTV stations located in Zone I that operate on channels 2-6 with an HAAT that exceeds 305 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERPmax=92.57-33.24*log10(HAAT)

(iii) For DTV stations located in Zone II or III that operate on channels 2-6 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERPmax=57.57-17.08*log10(HAAT)

(7) A DTV station that operates on a channel 7-13 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 30 kW if its antenna HAAT is at or below 305 meters and it is located in Zone I or a maximum ERP of 160 kW if its antenna HAAT is at or below 305 meters and it is located in Zone II or Zone III. A DTV station that operates on a channel 7-13 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operate with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

Maximum Allowable ERP and Antenna Height for DTV Stations In Zones II or III on Channels 7-13

Antenna HAAT (meters)ERP (kW)
61030
58034
55040
52047
49054
46064
42576
39592
365110
335132
305160

(ii) For DTV stations located in Zone I that operate on channels 7-13 with an HAAT that exceeds 305 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERPmax=97.35-33.24*log10(HAAT)

(iii) For DTV stations located in Zone II or III that operate on channels 7-13 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERPmax=62.34-17.08*log10(HAAT)

(8) A DTV station that operates on a channel 14-59 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 1000 kW if their antenna HAAT is at or below 365 meters. A DTV station that operates on a channel 14-59 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operates with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

Maximum Allowable ERP and Antenna Height for DTV Stations on Channels 14-59, All Zones

Antenna HAAT (meters)ERP (kW)
610316
580350
550400
520460
490540
460630
425750
395900
3651000

(ii) For DTV stations located in Zone I, II or III that operate on channels 14-59 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERPmax=72.57-17.08*log10(HAAT)

(g) DTV stations operating on channels above an analog TV station. (1) DTV stations operating on a channel allotment designated with a “c” in paragraph (b) of this section must maintain the pilot carrier frequency of the DTV signal 5.082138 MHz above the visual carrier frequency of any analog TV broadcast station that operates on the lower adjacent channel and is located within 88 kilometers. This frequency difference must be maintained within a tolerance of ±3 Hz.

(2) Unless it conflicts with operation complying with paragraph (g)(1) of this section, where a low power television station or TV translator station is operating on the lower adjacent channel within 32 km of the DTV station and notifies the DTV station that it intends to minimize interference by precisely maintaining its carrier frequencies, the DTV station shall cooperate in locking its carrier frequency to a common reference frequency and shall be responsible for any costs relating to its own transmission system in complying with this provision.

(h)(1) The power level of emissions on frequencies outside the authorized channel of operation must be attenuated no less than the following amounts below the average transmitted power within the authorized channel. In the first 500 kHz from the channel edge the emissions must be attenuated no less than 47 dB. More than 6 MHz from the channel edge, emissions must be attenuated no less than 110 dB. At any frequency between 0.5 and 6 MHz from the channel edge, emissions must be attenuated no less than the value determined by the following formula:

Attenuation in dB = −11.5(Δf + 3.6);

Where: Δf = frequency difference in MHz from the edge of the channel.

(2) This attenuation is based on a measurement bandwidth of 500 kHz. Other measurement bandwidths may be used as long as appropriate correction factors are applied. Measurements need not be made any closer to the band edge than one half of the resolution bandwidth of the measuring instrument. Emissions include sidebands, spurious emissions and radio frequency harmonics. Attenuation is to be measured at the output terminals of the transmitter (including any filters that may be employed). In the event of interference caused to any service, greater attenuation may be required.

(i) Post-Transition Table of DTV Allotments.

Community Channel No.
ALABAMA
Anniston9
Bessemer18
Birmingham*10, 13, 30, 36, 50
Demopolis*19
Dothan21, 36
Dozier*10
Florence14, 20, *22
Gadsden26, 45
Gulf Shores25
Homewood28
Huntsville19, *24, 32, 41, 48
Louisville*44
Mobile9, 15, 20, 23, 27, *41
Montgomery12, 20, *27, 31, 46
Mount Cheaha*7
Opelika30
Ozark33
Selma29, 42
Troy48
Tuscaloosa6, 33
Tuskegee22
ALASKA
Anchorage5, *8, 10, 12, 20, *26, 28, 33
Bethel*3
Fairbanks7, *9, 18, 26
Juneau*10, 11
Ketchikan13
North Pole20
Sitka7
ARIZONA
Douglas36
Flagstaff13, 18, 22, 32
Green Valley46
Holbrook*11
Kingman19
Mesa12
Phoenix*8, 10, 15, 17, 20, 24, 26, 33, 39, 49
Prescott7
Sierra Vista44
Tolleson51
Tucson9, 19, 23, 25, *28, *30, 32, 40
Yuma11, 13
ARKANSAS
Arkadelphia*13
Camden49
El Dorado*10, 27, 43
Eureka Springs34
Fayetteville*9, 15
Fort Smith18, 21, 27
Harrison31
Hot Springs26
Jonesboro8, *20, 48
Little Rock*7, 12, 22, 30, 32, *36, 44
Mountain View*13
Pine Bluff24, 39
Rogers50
Springdale39
CALIFORNIA
Anaheim32
Arcata22
Avalon47, 47c
Bakersfield10, 25, 33, 45
Barstow44
Bishop20
Calipatria36
Ceres*15
Chico24, 43
Clovis43
Concord14
Corona39
Cotati*23
El Centro9, 22
Eureka3, *11, 17, 28
Fort Bragg8
Fresno7, 30, 34, 38, *40
Hanford20
Huntington Beach*48
Long Beach18
Los Angeles7, 9, 11, 13, *28, 31, 34, 36, *41, 42, 43
Merced11
Modesto18
Monterey31, 32
Novato47
Oakland44
Ontario29
Oxnard24
Palm Springs42, 46
Paradise20
Porterville48
Rancho Palos Verdes51
Redding7, *9
Riverside35
Sacramento*9, 10, 21, 35, 40, 48
Salinas8, 13
San Bernardino*26, 38
San Diego8, 10, 18, 19, *30, 40
San Francisco7, 19, 27, 29, *30, *33, 38, 39, 45, 51
San Jose12, 36, 41, 49, *50
San Luis Obispo15, 34
San Mateo*43
Sanger36
Santa Ana33
Santa Barbara21, 27
Santa Maria19
Santa Rosa32
Stockton25, 26, 46
Twentynine Palms23
Vallejo34
Ventura49
Visalia28, *50
Watsonville*25
COLORADO
Boulder15
Broomfield*13
Castle Rock46
Colorado Springs22, 24, 49
Denver7, 9, *18, 19, 32, 34, 35, *40, 43, 51
Durango15, *20, 33
Fort Collins21
Glenwood Springs23
Grand Junction2, 7, 12, 15, *18
Greeley38
Longmont29
Montrose13
Pueblo*8, 42, 48
Steamboat Springs10
Sterling23
CONNECTICUT
Bridgeport42, *49
Hartford31, 33, *45, 46
New Britain35
New Haven10, 39, *41
New London26
Norwich*9
Waterbury20
DELAWARE
Dover5
Seaford*44
Wilmington2, *12, 31
DISTRICT OF COLUMBIA
Washington7, 9, *27, *33, 35, 36, 48, 50
FLORIDA
Boca Raton*40
Bradenton42
Cape Coral35
Clearwater21
Clermont17
Cocoa*30, 51
Daytona Beach11, 49
Destin48
Fort Lauderdale30
Fort Myers15, *31, 50
Fort Pierce34, *38
Fort Walton Beach40, 49, 50
Gainesville9, 16, *36
High Springs28
Hollywood47
Jacksonville*7, 13, 19, 32, 34, 42, *44
Key West3, 8
Lake Worth36
Lakeland19
Leesburg40, *46
Live Oak48
Marianna51
Melbourne43, 48
Miami7, 10, *18, 19, *20, 22, 23, 31, 32, 35, 46
Naples41, 45
New Smyrna Beach*33
Ocala31
Orange Park10
Orlando22, *23, 26, 27, 39, 41
Palm Beach49
Panama City9, 13, 18, *38
Panama City Beach47
Pensacola17, *31, 34, 45
Sarasota24
St. Petersburg10, 32, 44
Stuart42
Tallahassee24, 27, *32, 40
Tampa7, 12, *13, 29, *34, 47
Tequesta16
Tice33
Venice25
West Palm Beach12, 13, *27, 28
GEORGIA
Albany10, 12
Athens*8, 48
Atlanta10, 19, 20, *21, 25, 27, 39, *41, 43
Augusta12, 30, 31, 42
Bainbridge50
Baxley35
Brunswick24
Chatsworth*33
Cochran*7
Columbus11, 15, *23, 35, 49
Cordele51
Dalton16
Dawson*8
Macon13, 16, 40, 45
Monroe44
Pelham*6
Perry32
Rome51
Savannah*9, 11, 22, 39
Thomasville46
Toccoa24
Valdosta43
Waycross*8
Wrens*6
HAWAII
Hilo*9, 11, 13, 22, 23
Honolulu8, *11, 19, 22, 23, 27, 31, 33, 35, *38, 40, *43
Kailua50
Kailua Kona25
Kaneohe41
Wailuku7, *10, 12, 16, 21, 24
Waimanalo15
IDAHO
Boise7, 9, *21, 39
Caldwell10
Coeur d'Alene*45
Filer*18
Idaho Falls8, 20, 36
Lewiston32
Moscow*12
Nampa13, 24
Pocatello15, *17, 23, 31
Sun Valley5
Twin Falls11, *22, 34
ILLINOIS
Aurora50
Bloomington28
Carbondale*8
Champaign41, 48
Charleston*50
Chicago12, 19, *21, 27, 29, 31, 43, 44, 45, *47
Decatur17, 22