(p) that, for some frequency sharing situations between near-Earth research satellites and certain representative terrestrial services, separations of several hundreds of kilometres between the earth terminals may be required and that, in many parts of the world, separations of this magnitude are not readily attainable; (q) that frequency sharing among near-Earth research satellites is desirable and feasible; (r) that difficulties can be expected when frequencies are shared between near-Earth research satellites and stations in other Services, due to the technical problems of furnishing the required protection against terrestrial Services, UNANIMOUSLY RECOMMENDS 1. that the range below 1 GHz is technically suitable for near-Earth research satellites, with each satellite using radio-frequency bandwidths varying from 10 to 500 kHz per link, for accomplishing telemetering, wideband data transmission, tracking, telecommand and voice functions; 2. that the range between 1 GHz and 6 GHz is technically suitable for near-Earth research satellites, with each satellite using radio-frequency bandwidths varying from 500 kHz to 4 MHz per link, for accomplishing telemetering, wideband data transmission, tracking, telecommand, voice and television functions; 3. that the range between 6 and 10 GHz is technically suitable for near-Earth research satellites, with each satellite using radio frequency bandwidths varying from 500 kHz to 20 MHz per link, for accomplishing telemetering, wideband data transmission, tracking, telecommand, voice and television functions; 4. that the range between 10 GHz and 30 GHz is technically suitable for near-Earth research satellites, with each satellite using radio frequency bandwidths ranging from 1 MHz to 300 MHz per link, for accomplishing telemetering, wideband data transmission and television functions; 5. that high frequencies below about 25 MHz are technically suitable for two-way voice communication during manned-mission near-Earth and recovery phases; 6. that, when necessary, for emergency purposes in manned near-Earth missions, the recognized distress frequencies be used in accordance with the Radio Regulations; 7. that consideration be given to the availability of coherently related frequencies spaced by more than 6% of the higher frequency for precision tracking systems; 8. that frequency sharing be accomplished to the maximum extent feasible among near-Earth research satellites; 9. that the protection criterion for earth receiving stations be established as follows: for frequencies greater than 1 GHz and up to at least 10 GHz, the total time for which the power spectral density of noise-like interference or the total power of CW-type interference in any single band and all sets of bands 1 Hz wide is greater than -220 dB(W/Hz) at the input terminals of the receiver, shall not exceed 5 minutes per day, for manned research missions (0.1% of the time being permissible for other near-Earth research missions); for frequencies less than 1 GHz, the permissible interference may be increased at the rate of 20 dB per decreasing frequency decade; 10. that the protection criterion for receivers in spacecraft be established as follows: for frequencies greater than 300 MHz and up to at least 10 GHz, the total time during which the power spectral-density of noise-like interference or the total power of CW-type interference in any single band or all sets of bands 1 kHz wide is greater than -171 dB(W/kHz) at the input terminals of the receiver, shall not exceed 5 minutes per day for manned research missions (—161 dB(W/kHz) during a maximum of 0.1% of the time being permissible for other near-Earth research missions); for frequencies less than 300 MHz, the permissible interference may be increased at the rate of 20 dB per decreasing frequency decade; 11. that note be taken of the difficulties to be expected in frequency sharing between near-Earth research satellites and stations in other services.
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