f enable each time zone to have its own programmes. satellites for purpose of this kind may be limited, for the developed Acknowledgements 51/19 regions of the World, not by shortage of demand but by difficulties CCIR (1980d) Maximum allowable values of interference from of supply, arising from increasing congestion in the geostationary line-of-sight radio relay systems in a telephone channel of a satellite orbit. These difficulties will, no doubt, lead to the use of the system in the fixed satellite service employing frequency modu- frequency bands allocated to the fixed satellite service around lation, when the same frequency bands are shared by both 20GHz and 30GHz (see Table 51.1) for applications where the systems, CCIR Rec. 356, ITU Geneva. additional cost of operating in these bands can be absorbed. Chitre, N.K.M. and Fuenzalida, J.C. (1972) Baseband distortion It is clear that there will be strong growth in demand for the use caused by intermodulation in multicarrier FM systems, COM- of satellites for communication with mobile stations, and in particu- SAT Tech. Rev, 2, 1 p. 147. lar with road vehicles in sparsely populated regions. There will also Clarke, A.C. (1945) Extra-terrestrial relays, Wireless World, p. 305. be a considerable demand for communication by satellite with Dickieson, A.C. (1963) The TELSTAR experiment, Bell Syst. Tech. aircraft, to provide telephone services for passengers and probably J, 42 p. 739, (and associated papers). also for air traffic control purposes. Major growth could not be EUTELSAT (1981) TDMA/DSI system specification, EUTELSAT supplied without an increase in the bandwidth allocated for these Document ESC/C-11-17 Rev 1, September. purposes in a technically suitable part of the spectrum, and an Evans, B.G. et al. (1986) Baseband switches and transmultiplexers administrative conference of the ITU, meeting in February 1992, for use in an on-board processing mobile/business satellite sys- considered proposals for making such an increase. These proposals tem, Proc. IEE, Part