Sec.  101.145   Interference to geostationary-satellites.

   These limitations are necessary to minimize the probability of harmful
   interference to reception in the bands 2655–2690 MHz, 5925–7075 MHz, and
   12.7–13.25 GHz on board geostationary-space stations in the fixed-satellite
   service.

   (a) Stations authorized prior to July 1, 1976 in the band 2655–2690 MHz,
   which exceed the power levels in paragraphs (b) and (c) of this section are
   permitted to operate indefinitely, provided that the operation of such
   stations does not result in harmful interference to reception in these bands
   on board geostationary space stations.

   (b) 2655 to 2690 MHz and 5925 to 7075 MHz. No directional transmitting
   antenna utilized by a fixed station operating in these bands (may be aimed
   within 2 degrees of the geostationary-satellite orbit, taking into account
   atmospheric  refraction.  However,  exception  may  be made in unusual
   circumstances upon a showing that there is no reasonable alternative to the
   transmission path proposed. If there is no evidence that such exception
   would cause possible harmful interference to an authorized satellite system,
   said transmission path may be authorized on waiver basis where the maximum
   value of the equivalent isotropically radiated power (EIRP) does not exceed:

   (1)  +47  dBW  for any antenna beam directed within 0.5 degrees of the
   stationary satellite orbit; or

   (2) +47 to +55 dBW, on a linear decibel scale (8 dB per degree) for any
   antenna beam directed between 0.5 degrees and 1.5 degrees of the stationary
   orbit.

   (c) 12.7 to 13.25 GHz. No directional transmitting antenna utilized by a
   fixed station operating in this band may be aimed within 1.5 degrees of the
   geostationary-satellite orbit, taking into account atmospheric refraction.
   However, exception may be made in unusual circumstances upon a showing that
   there is no reasonable alternative to the transmission path proposed. If
   there  is no evidence that such exception would cause possible harmful
   interference to an authorized satellite system, said transmission path may
   be authorized on waiver basis where the maximum value of the equivalent
   isotropically radiated power (EIRP) does not exceed +45 dBW for any antenna
   beam directed within 1.5 degrees of the stationary satellite orbit.

   (d) Methods for calculating the azimuths to be avoided may be found in: CCIR
   Report No. 393 (Green Books), New Delhi, 1970; in “Radio-Relay Antenna
   Pointing for controlled Interference With Geostationary-Satellites” by C. W.
   Lundgren and A. S. May, Bell System Technical Journal, Vol. 48, No. 10, pp.
   3387–3422, December 1969; and in “Geostationary Orbit Avoidance Computer
   Program” by Richard G. Gould, Common Carrier Bureau Report CC–7201, FCC,
   Washington, DC, 1972. This latter report is available through the National
   Technical Information Service, U.S. Department of Commerce, Springfield, VA
   22151, in printed form (PB–211 500) or source card deck (PB–211 501).

   [ 61 FR 26677 , May 28, 1996, as amended at  65 FR 38330 , June 20, 2000;  68 FR 12777 , Mar. 17, 2003]