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Title 47

Displaying title 47, up to date as of 9/22/2021. Title 47 was last amended 9/22/2021.

Title 47

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§ 101.113 Transmitter power limitations.

(a) On any authorized frequency, the average power delivered to an antenna in this service must be the minimum amount of power necessary to carry out the communications desired. Application of this principle includes, but is not to be limited to, requiring a licensee who replaces one or more of its antennas with larger antennas to reduce its antenna input power by an amount appropriate to compensate for the increased primary lobe gain of the replacement antenna(s). In no event shall the average equivalent isotropically radiated power (EIRP), as referenced to an isotropic radiator, exceed the values specified below. In cases of harmful interference, the Commission may, after notice and opportunity for hearing, order a change in the effective radiated power of this station. Further, the output power of a transmitter on any authorized frequency in this service may not exceed the following:

Frequency band (MHz) Maximum allowable EIRP1 2
Fixed1 2 (dBW) Mobile (dBW)
928.0-929.0(2) + 17
932.0-932.5(2) + 17
932.5-935.0 + 40
941.0-941.5(2) + 30 + 14
941.5-944.0 + 40
952.0-960.0(2) + 40 + 14
1,850-1,990 + 45
2,110-2,150 + 45
2,150-2,1803 + 45
2,180-2,200 + 45
2,450-2,500 + 45
2,500-2,686
2,686-2,690 + 45
3,700-4,200 + 55
5,925-6,425 + 55
6,425-6,525 + 35
6,525-6,875 + 55
6,875-7,125 + 55
10,550 to 10,6005 + 55
10,600 to 10,6805 + 40
10,700-11,700 + 55
12,200-12,70011 + 50
12,700-13,2004 + 50
13,200-13,2504 + 55
14,200-14,40012 + 45
17,700-18,600 + 55
18,600-18,8006 + 35
18,800-19,700 5 + 55
21,200-23,60010 + 55
24,250-25,250 5+ 55
29,100-29,250 (7)
31,000 to 31,0758 9 30 dBW/MHz 30 dBW/MHz
31,075 to 31,2258 9 30 dBW/MHz 30 dBW/MHz
31,225 to 31,3008 9 30 dBW/MHz 30 dBW/MHz
71,000-76,00013 + 55 + 55
81,000-86,00013 + 55 + 55
92,000-95,000 + 55 + 55

(b) The power of transmitters that use Automatic Transmitter Power Control shall not exceed the power input or output specified in the instrument of station authorization. The power of non-ATPC transmitters shall be maintained as near as practicable to the power input or output specified in the instrument of station authorization.

(c)

(1) Transmitter power limitations. Point-to-point stations in the 29.1-29.25 GHz band for the LMDS backbone between LMDS hubs shall be limited to a maximum allowable e.i.r.p. density per carrier of 23 dBW/MHz in any one megahertz in clear air, and may exceed this limit by employment of adaptive power control in cases where link propagation attenuation exceeds the clear air value due to precipitation and only to the extent that the link is impaired.

(2) Hub transmitter EIRP spectral area, density limit. LMDS applicants shall demonstrate that, under clear air operating conditions, the maximum aggregate of LMDS transmitting hub stations in a Basic Trading Area in the 29.1-29.25 GHz band will not transmit a co-frequency hub-to-subscriber e.i.r.p. spectral area density in any azimuthal direction in excess of X dBW/(MHz-km2) when averaged over any 4.375 MHz band, where X is defined in Table 1. Individual hub stations may exceed their clear air e.i.r.p.s by employment of adaptive power control in cases where link propagation attenuation exceeds the clear air value and only to the extent that the link is impaired.

(i) The e.i.r.p. aggregate spectral area density is calculated as follows:

where:

N = number of co-frequency hubs in BTA.

A = Area of BTA in km2.

pi = spectral power density into antenna of i-th hub (in W/MHz).

gi = gain of i-th hub antenna at zero degree elevation angle.

Each pi and gi are in the same 1 MHz within the designated frequency band.

(ii) The climate zones in Table 1 are defined for different geographic locations within the US as shown in Appendix 28 of the ITU Radio Regulations.

Table 11

Climate zone e.i.r.p. Spectral Density (Clear Air) (dBW/MHz-km2)2
1 −23
2 −25
3,4,5 −26

(3) Hub transmitter e.i.r.p. spectral area density limit at elevation angles above the horizon. LMDS applicants shall demonstrate that, under clear air operating conditions, the maximum aggregate of LMDS transmitting hub stations in a Basic Trading Area in the 29.1-29.25 GHz band will not transmit a co-frequency hub-to-subscriber e.i.r.p. spectral area density in any azimuthal direction in excess of X dBW/(MHz-km2) when averaged over any 4.375 MHz band where X is defined in Table 2. Individual hub stations may exceed their clear air e.i.r.p.s by employment of adaptive power control in cases where link propagation attenuation exceeds the clear air value and only to the extent that the link is impaired.

(i) The e.i.r.p. aggregate spectral area density is calculated as follows:

where:

N = number of co-frequency hubs in BTA.

A = Area of BTA in km2.

e.i.r.p. (ai) = equivalent isotropic radiated spectral power density of the i-th hub (in W/MHz) at elevation angle a where a is the angle in degrees of elevation above horizon. e.i.r.p.(0°) is the hub e.i.r.p. area density at the horizon used in Section 101.113c(2). The nominal antenna pattern will be used for elevation angles between 0° and 8°, and average levels will be used for angles beyond 8°, where average levels will be calculated by sampling the antenna patterns in each 1° interval between 8° and 9015, dividing by 83.

Table 2

Elevation angle (a) Relative e.i.r.p. density (dBW/MHz-km2)
0° ≤a ≤4.0° e.i.r.p.(a) = e.i.r.p.(0°) + 20 log (sinΠ x)(1/Π x) where x = (a + 1)/7.5°.
4.0° <a ≤7.7° e.i.r.p.(a) = e.i.r.p.(0°) - 3.85a + 7.7.
a >7.7° e.i.r.p.(a) = e.i.r.p.(0°) - 22.

(ii) LMDS system licensees in two or more BTAs may individually or collectively deviate from the spectral area density computed above by averaging the power over any 200 km by 400 km area, provided that the aggregate interference to the satellite receiver is no greater than if the spectral area density were as specified in Table 1. A showing to the Commission comparing both methods of computation is required and copies shall be served on any affected non-GSO MSS providers.

(4) Power reduction techniques. LMDS hub transmitters shall employ methods to reduce average power levels received by non-geostationary mobile satellite receivers, to the extent necessary to comply with paragraphs (c)(1) and (c)(2) of this section, by employing the methods set forth below:

(i) Alternate polarizations. LMDS hub transmitters in the LMDS service area may employ both vertical and horizontal linear polarizations such that 50 percent (plus or minus 10 percent) of the hub transmitters shall employ vertical polarization and 50 percent (plus or minus 10 percent) shall employ horizontal polarization.

(ii) Frequency interleaving. LMDS hub transmitters in the LMDS service area may employ frequency interleaving such that 50 percent (plus or minus 10 percent) of the hub transmitters shall employ channel center frequencies which are different by one-half the channel bandwidth of the other 50 percent (plus or minus 10 percent) of the hub transmitters.

(iii) Alternative methods. As alternatives to paragraphs (c)(4)(i) and (c)(4)(ii) of this section, LMDS operators may employ such other methods as may be shown to achieve equivalent reductions in average power density received by non-GSO MSS satellite receivers.

[61 FR 26677, May 28, 1996]