0MHz In choosing frequencies for assignment to mobile stations, an are allocated for the mobile services in general, shared mostly with administration must often take care to exclude from the vicinity of, broadcasting. These bands are used considerably for land mobile for example, a radio astronomy observatory, the use of a frequency and aeronautical (Off route) systems but broadcasting is the major at which the observatory operates. Large amounts of spectrum are also allocated for mobile services 26.4.4 The amateur services above 1GHz, sharing with the fixed service (and in many cases the fixed satellite service). For technical reasons these allocations There are allocations for the amateur service in every part of the become less suitable for communication with moving vehicles as radio spectrum in use today. Many of these bands are allocated for the frequency rises but considerable use is made of them for trans- the amateur satellite service also. However, many of these alloca- portable equipment, often used for television outside broadcasting tions are also shared with other services, typically the radiolocation links. Where these bands are shared with up links of the fixed service, and in some bands the amateur services have secondary satellite service there are power constraints on mobile service trans- status. mitters similar to those which govern the fixed service sharing the There are various internationally agreed technical constraints and same bands. operational constraints on amateur stations in the various bands. These constraints typically limit the power and bandwidth of emissions. Administrations authorising the launch of an amateur 26.4.3.2 Links via satellite satellite operating in bands shared with other services undertake to ensure that the ground telecommand facilities will be good enough As with the (terrestrial) mobile services, frequency bands are allo- to keep interference from the satellite under control. cated for the mobile satellite service, usable for facilities for any The regulation