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 941.5–944 MHz, 944–952 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. In the 941.5–944 MHz band, low power auxiliary station usage also is secondary to Federal operations in the band. In each of these bands, 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 station (LPAS) authorizations are limited to operations at fixed locations, and only to the extent that applicable requirements have been met for the proposed operations at those specified locations.
(1) Each authorization is limited to specific events or situations for which there is a need to deploy large numbers of LPAS for specified time periods, and use of other available spectrum resources at that particular location is insufficient to meet the LPAS licensee's needs.
(2) The access to spectrum in the band must be coordinated with the frequency coordinator for aeronautical mobile telemetry, the Aerospace and Flight Test Radio Coordinating Committee (AFTRCC) prior to operations at the specified location and period of time, with AFTRCC indicating whether any specific frequencies in the band are unavailable for use. LPAS devices must complete authentication and location verification before operations begin, 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.
(3) LPAS users may have access to no more than 30 megahertz of spectrum (one third of the 1435–1525 MHz band) for their operations at the specified locations. Different users in the same general area each can access up to 30 megahertz of spectrum for their respective operations. All licensees that have successfully coordinated with AFTRCC for access to the 1435–1525 MHz band for operations at their specified locations in the same general area must, to the extent necessary, coordinate their particular access to and use of spectrum with other licensees to minimize the potential for interference between and among the different operations.