§  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/m2/MHz as measured at the earth station antenna.

   (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/m2/MHz as measured at the earth station antenna.

   (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/m2/MHz as measured at the TT&C earth station
   antenna.