d 28MHz, have been allocated for the maritime service or the links in several frequency bands between 11.7GHz and 18.3GHz, aeronautical service (Route or Off route) and a few bands have been some of which are shared with the fixed satellite service. Special allocated in this part of the spectrum for the land mobile service. frequency co-ordination processes (ITU, 1990, Appendices 30 and These bands are used mainly for long distance, ionospherically 30A) additional to those outlined above, are used to ensure that propagated links. Most of the maritime bands have been sub divided International spectrum management 26/11 SATELLITE B fically for the aeronautical, maritime and land mobile satellite SATELLITE C1 services. Some aeronautical mobile satellite allocations are specifi- cally reserved for "Route" purposes. The most important of the mobile satellite allocations are between 1530MHz and 1660MHz; sub bands in this part of the spectrum have been allocated for maritime, aeronautical (Route) and land mobile purposes. There is little sharing with other services. These Y GHz INTERFERENCE bands are used entirely for links between satellites and mobile earth X GHz MODE 8 stations, any associated feeder links between satellites and earth (QUASI-ANTIPODAL) stations at permanent locations on the ground being assigned fre- quencies in bands allocated to the fixed satellite service; see Section 26.4.2. There are also frequency allocations to the mobile satellite Y GHz EARTH service in many other parts of the spectrum, many of them shared with the fixed satellite service. 26.4.3.3 Spectrum management Y GHz X GHz Very simple procedures are used for international registration when frequencies are assigned to stations at fixed locations (typically coast stations and aeronautical stations) in accordance with a fre- quency assignment or frequency allotment plan. In other bands, frequencies are chosen by inspection or from radio channelling SATELLITE C2 plans, national or international, for assignment to coast stations, aeronautica