.1 Terrestrial links 2. Down links at 4.5 to 4.8, 10.7 to 10.95GHz and/or 11.2 to 11.45GHz. Frequency bands are allocated for the mobile service, to be used for links with, or between, any kind of mobile station, but other alloca- This plan provides for each country to set up one satellite network tions are made specifically for the aeronautical mobile, maritime covering its own territory, subject to broad limits on the parameters mobile and land mobile services respectively. There is a further sub of the equipment and the emissions that are used, whenever it is division of allocations for aeronautical use as between "Route" ready to do so, without risk that networks set up by other countries bands reserved for air traffic control purposes on civil air routes, and will have pre-empted its option. "Off route" bands, used for other aeronautical purposes. Narrow In all other frequency bands there is a detailed procedure of bands at various frequencies have been identified for use in distress frequency co-ordination, designed to give every administration with and other emergencies; special measures are taken to prevent inter- a reasonable concern about interference the right to discuss prospec- ference arising in these bands. tive interference levels with the administration proposing to set up There are maritime mobile allocations below 160kHz but their use the new network. The chief parameters that are open to negotiation is declining. The maritime band around 500kHz, limited to radio- when excessive interference is foreseen are the orbital locations of telegraphy, is in heavy use. Maritime and aeronautical allocations the satellites, frequency assignments and earth station antenna char- around 2MHz and 3MHz are also in substantial use, although the acteristics. mobile services must share these bands with other services. As will be seen from Section 26.4.6. frequency assignment plans Over fifty narrow bands, mostly unshared, spread between 4MHz have been agreed for satellite broadcasting and the associated feeder an