47 CFR 74.803 - Frequency selection to avoid interference.
(a) Where two or more low power auxiliary licensees need to operate in the same area, the licensees shall endeavor to select frequencies or schedule operation in such manner as to avoid mutual interference. If a mutually satisfactory arrangement cannot be reached, the Commission shall be notified and it will specify the frequency or frequencies to be employed by each licensee.
(b) The selection of frequencies in the bands allocated for TV broadcasting for use in any area shall be guided by the need to avoid interference to TV broadcast reception. In these bands, low power auxiliary station usage is secondary to TV broadcasting and land mobile stations operating in the UHF-TV spectrum and must not cause harmful interference. If such interference occurs, low power auxiliary station operation must immediately cease and may not be resumed until the interference problem has been resolved.
(c) In the 941.500-952.000 MHz, 952.850-956.250 MHz, 956.45-959.85 MHz, 6875.000-6900.000 MHz, and 7100.000-7125.000 MHz bands low power auxiliary station usage is secondary to other uses (e.g., Aural Broadcast Auxiliary, Television Broadcast Auxiliary, Cable Relay Service, Fixed Point to Point Microwave) and must not cause harmful interference. Applicants are responsible for selecting the frequency assignments that are least likely to result in mutual interference with other licensees in the same area. Applicants must consult local frequency coordination committees, where they exist, for information on frequencies available in the area. In selecting frequencies, consideration should be given to the relative location of receive points, normal transmission paths, and the nature of the contemplated operation.
(d) In the 1435-1525 MHz band, low power auxiliary stations (LPAS) are limited to operations at specific fixed locations that have been coordinated with the frequency coordinator for aeronautical mobile telemetry, the Aerospace and Flight Test Radio Coordinating Committee. LPAS devices must complete authentication and location verification before operation begins, employ software-based controls or similar functionality to prevent devices in the band from operating except in the specific channels, locations, and time periods that have been coordinated, and be capable of being tuned to any frequency in the band. Use is limited to situations where there is a need to deploy large numbers of LPAS for specified time periods, and use of other available spectrum resources is insufficient to meet the LPAS licensee's needs at the specific location. All LPAS devices operating in a particular area in the band may have access to no more than 30 megahertz of spectrum in the band at a given time.