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e-CFR data is current as of September 24, 2020

Title 47Chapter ISubchapter APart 1Subpart BB → §1.30001

Title 47: Telecommunication
Subpart BB—Disturbance of AM Broadcast Station Antenna Patterns

§1.30001   Definitions.

For purposes of this subpart:

(a) Wavelength at the AM frequency. In this subpart, critical distances from an AM station are described in terms of the AM wavelength. The AM wavelength, expressed in meters, is computed as follows:

(300 meters)/(AM frequency in megahertz) = AM wavelength in meters.

For example, at the AM frequency of 1000 kHz, or 1 MHz, the wavelength is (300/1 MHz) = 300 meters.

(b) Electrical degrees at the AM frequency. This term describes the height of a proposed tower as a function of the frequency of a nearby AM station. To compute tower height in electrical degrees, first determine the AM wavelength in meters as described in paragraph (a) of this section. Tower height in electrical degrees is computed as follows: (Tower height in meters)/(AM wavelength in meters) × 360 degrees = Tower height in electrical degrees. For example, if the AM frequency is 1000 kHz, then the wavelength is 300 meters, per paragraph (a) of this section. A nearby tower 75 meters tall is therefore [75/300] × 360 = 90 electrical degrees tall at the AM frequency.

(c) Proponent. The term proponent refers in this section to the party proposing tower construction or significant modification of an existing tower or proposing installation of an antenna on an AM tower.

(d) Distance from the AM station. The distance shall be calculated from the tower coordinates in the case of a nondirectional AM station, or from the array center coordinates given in CDBS or any successor database for a directional AM station.

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