11. that a deep-space research service cannot share space-to-Earth bands with: 11.1 transmitting aeronautical mobile stations, and 11.2 transmitting satellite stations. When coordination is practicable, sharing is feasible with other stations of all services. In some cases, coordination distances may be unacceptably great. RECOMMENDATION 364-3 * TELECOMMUNICATION LINKS FOR MANNED AND UNMANNED NEAR-EARTH RESEARCH SATELLITES Frequencies, bandwidths and criteria for protection from interference (Questions 18/2 and 22/2) (1963 - 1966 - 1970- 1978) The CCIR, CONSIDERING (a) that suitable operating frequencies, required radio-frequency bandwidths, and limiting interference criteria for near-Earth satellite telecommunication links are determined by the technical considerations set forth in the appropriate Reports; (b) that, based on past experience, it is expected that of the order of 100 active research near-Earth satellites may be in orbit simultaneously; (c) that two-way communication is required for many near-Earth missions, and is vital for manned missions; (d) that various radio-frequency bands are suitable for near-Earth satellite telecommunication links, and that the variety of functions and the conditions under which they must be performed divide this region into the following suitable regions: below 1 GHz, 1 to 6 GHz, 6 to 10 GHz, and 10 to 30 GHz; (e) that telemetering data links typically require radio-frequency bandwidths ranging from 10 kHz to 20 MHz per link in the frequency range from 100 MHz to 30 GHz, with a bandwidth of 10 kHz in the lower portion, and up to 20 MHz in the upper portion; (f) that tracking links typically require radio-frequency bandwidths ranging from 10 kHz to 100 MHz per link in the frequency range from 100 MHz to 15 GHz with bandwidths of 10 kHz in the lower portion and up to 100 MHz in the upper portion of this range, the latter being required for high precision two-way, coherent, range and range rate systems; (g) that voice links typically require radio-frequency bandwidths ranging from 3 kHz to 45 kHz per link; (h) that wideband data and television links typically require radio-frequency bandwidths within the range 50 kHz to 300 MHz in the frequency range from 100 MHz to 30 GHz, with preference for 50 kHz in the lower portion and 300 MHz in the upper portion of uiis range; (j) that the operating noise temperatures of earth-station telemetering and tracking receiving systems usually range from 30 K. above 1 GHz to 3000 K at 100 MHz (equivalent to -214 dB(W/Hz) and - 194 dB(W/Hz)); (k) that earth-station antennae for satellite communication do not operate at elevation angles less than 5°, except for initial acquisition; (1) that typical operating noise temperatures for receivers in near-Earth research spacecraft are approximately 600 K (—171 dB(W/kHz)), but that measures can be taken to protect the spacecraft receiving system against interference approximately 10 dB greater than this noise level; (m) that telecommand requirements can normally be satisfied by one data link channel per craft with radio-frequency bandwidths ranging from 10 kHz at 100 MHz to 500 kHz at 15 GHz, largely determined by the Doppler shift which may be of the order of 1 x 10 4 of the carrier frequency; (n) that coding techniques and the future use of narrow-beam antennae may make possible the control of several crafts using the same radio-frequency telecommand channel; (o) that circuit design in spacecraft for high precision coherent tracking systems dictate that two frequencies be used, spaced by at least 6% of the higher one; ♦ This Recommendation is brought to the attention of Study Groups 1, 4, 7, 8, 9, 10 and 11.
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