§ 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 with EIRP
   greater than 35 dBW 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 with EIRP greater than 45 dBW
   may be aimed within 1.5 degrees of the geostationary-satellite orbit,
   taking into account atmospheric refraction.

   (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;  77 FR 54433 , Sept. 5, 2012]

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