47 C.F.R. § 27.1423
Protection of incumbent operations
(a) To protect incumbent earth stations from out-of-band emissions from fixed stations, base stations and mobiles, the power flux density (PFD) of any emissions within the 4000-4200 MHz band must not exceed −124 dBW/m
(b) To protect incumbent earth stations from blocking, the power flux density (PFD) of any emissions within the 3700-3980 MHz band must not exceed −16 dBW/m
(c) All 3.7 GHz Service licensees, prior to initiating operations from any base or fixed station, must coordinate cochannel frequency usage with all incumbent Telemetry, Tracking, and Command (TT&C) earth stations within a 70 km radius. The licensee must ensure that the aggregated power from its operations meets an interference to noise ratio (I/N) of −6 dB to the TT&C earth station receiver. A base station's operation will be defined as cochannel when any of the 3.7 GHz Service licensee's authorized frequencies are separated from the center frequency of the TT&C earth station by less than 150% of the maximum emission bandwidth in use by the TT&C earth station.
(d) All 3.7 GHz Service licensees operating on an adjacent channel to an incumbent TT&C earth station must ensure that the aggregated power from its operations meets an interference to noise ratio (I/N) of −6 dB to the TT&C earth station receiver.
(e) To protect incumbent TT&C earth stations from blocking, the power flux density (PFD) of any emissions within the 3700-3980 MHz band must not exceed −16 dBW/m