hich frequency assignment satellites (the broadcasting satellite service) and currently being plans have been agreed for satellite broadcasting (ITU, 1990g) and taken into use, albeit slowly, for television are as in Table 51.3 in the bands at 14.5GHz and1 GHz where there are corresponding feeder link assignment plans (ITU, 1990h), limits have been agreed for all of the satellite and earth station characteristics and all of the Table 51.3 Frequency bands allocated for down-links from emission and orbital parameters which significantly affect the level broadcasting satellites of interference that these systems can cause to one another. With very minor exceptions, the radio stations of other services which also have allocations in these bands are not permitted to cause Region Frequency band significant interference to satellite broadcasting, and they must ITU region 1 (Europe Africa Asia west of 11.7 - 12.5 GHz accept any interference which they receive from authorised satellite the Persian Gulf and the whole of the broadcasting. USSR) In the frequency bands at 4.5, 7.0, 10.8, 11.3 and 13GHz, which ITU region 2 (North and South America) 12.2 - 12.7 GHz were used in drawing up the frequency and orbital slot allotment ITU region 3 (Australasia and Asia 11.7 - 12.2 GHz plan which provides for one fixed satellite system per country (ITU, excluding USSR and countries west of the 1990b), constraints were placed on equipment characteristics and Persian Gulf) emission and orbital parameters in more flexible ways than were used for satellite broadcasting at 12GHz. There are also procedures to be used when systems are set up, using these allotments, to ensure that these systems do not interfere with one another. However, these Frequency and orbital slot assignment plans have been drawn up frequency bands are also allocated for terrestrial radio services and the measures outlined below to limit interference between terrestrial for these bands (ITU, 1990g). The feeder links which carry pro- gramme signals up to these satellite