lite techniques 1GHz and 80GHz, all shared with terrestrial radar. For data links the respectively. Additional services have been defined to enable earth exploration satellite and meteorological satellite services each radionavigation systems, which provide safety services to be distin- have one or two allocations between 1GHz and 20GHz, wideband guished from radiolocation systems, which do not provide safety and shared on equal terms with telecommunications services. The services, and to enable bands reserved for maritime systems to be other services have in aggregate a substantial number of allocations distinguished from bands reserved for aeronautical systems. in many parts of the spectrum for communication, but most are With few exceptions the radionavigation service allocations are narrow, many have secondary status and all are shared with tele- communications services. not shared with allocations to telecommunications services. Where such sharing does arise, radionavigation service assignments have advantages over those of the telecommunications services, if there should be interference, because the former always have primary allocation status, there are frequency assignment plans for it in some Table 26.1 Frequency assignment plans for broadcasting bands and additional protection arises from the "safety service" satellite service status of the radionavigation service. Radiolocation service alloca- tions are sometimes shared with allocations for telecommunications services. Region 1 Region 2 Region 3 Broadcasting 11.7 - 12.5 12.2 - 12.7 11.7 - 12.2 26.4.8 Exploration and research using radio down-link bands (GHz) The last group of services consists of the space research, earth Feeder up- 14.5 - 14.8 17.3 17.8 14.5 - 14.8 exploration satellite, meteorological satellite, radio astronomy, link bands and 17.3 - and 17.3 - space operation, meteorological aids, standard frequency and time (GHz) signal and standard frequency and time signal satellite services. 26/14 Radio spectrum management National frequency man