Goto Section: 101.143 | 101.147 | Table of Contents
Revised as of September 1, 2021
Goto Year:2020 |
§ 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
(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
(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]
Goto Section: 101.143 | 101.147
Goto Year: 2020 |
CiteFind - See documents on FCC website that
cite this rule
Want to support this service?
Report errors in
this rule. Since these rules are converted to HTML by machine, it's possible errors have been made. Please
help us improve these rules by clicking the Report FCC Rule Errors link to report an error.
Helping make public information public