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Airband'The airband or air band is the band of frequencies used for radio communication in aviation. In general, airband is used to mean the VHF band between 108 MHz and 137 MHz, which covers its use for commercial and general aviation, radionavigational aids, air traffic control and so on. Military aircraft also operate using additional frequencies (225 - 400 MHz) which are not part of the airband. The lower part of the band, from 108 to 117.975 MHz, is reserved for navigational aids such as VOR beacons, ATIS and ASOS messages, and precision approach systems such as ILS. Some types of aviation-related stations, such as NDBs and DMEs, do not operate on these frequencies; in the case of NDB, the mediumwave frequency band is used. The rest of the airband is allocated to voice communications using amplitude modulation. Channel spacing on the airband is traditionally 25 kHz, but increasing congestion has led to further subdivision into 8.33 kHz channels in some areas. A switch to digital radios has been contemplated, as this would greatly increase capacity by reducing bandwidth. However, this has yet to get off the ground, partly because the mobility of aircraft necessitates complete international coordination.
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