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Usually these other frequency bands are only used in oceanic and remote areas, though they work over wider areas or even globally. Military aircraft also use a dedicated UHF-AM band from 225.0 to 399.95 MHz for air-to-air and air-to-ground, including air traffic control communication.
The aircraft emergency frequency (also known in the USA as Guard) is a frequency used on the aircraft band reserved for emergency communications for aircraft in distress.The frequencies are 121.5 MHz for civilian, also known as International Air Distress (IAD), International Aeronautical Emergency Frequency, [1] or VHF Guard, [1] and 243.0 MHz—the second harmonic of VHF guard—for military ...
Marine VHF radio is a worldwide system of two way radio transceivers on ships and watercraft used for bidirectional voice communication from ship-to-ship, ship-to-shore (for example with harbormasters), and in certain circumstances ship-to-aircraft.
VOLMET (French origin vol (flight) and météo (weather report)), or meteorological information for aircraft in flight, is a worldwide network of radio stations that broadcast TAF, SIGMET and METAR reports on shortwave frequencies, and in some countries on VHF too. Reports are sent in upper sideband mode, using automated voice transmissions.
Conceptual of the ADS-B system, illustrating radio links between aircraft, ground station and satellite. Automatic Dependent Surveillance–Broadcast (ADS-B) is an aviation surveillance technology and form of electronic conspicuity in which an aircraft determines its position via satellite navigation or other sensors and periodically broadcasts its position and other related data, enabling it ...
Before 1 October 2002 it was known as the Global High Frequency System (GHFS). HFGCS stations tend to operate in the aviation bands clustered around 5, 6, 8 and 11/12 MHz, although other frequencies are in use. The primary HFGCS voice frequencies are 4724.0 kHz, 8992.0 kHz, 11175.0 kHz, and 15016.0 kHz.
The transmitter component was the BC-778. The frequency was 500 kHz at 4.8 watts, giving it a range of 200 miles (300 km; 200 nmi). Keying could be automatic SOS (including the 4-second long dash for autoalarm), or manual. Crystals for frequency control were a scarce item for the U.S. during the war and the SCR-578 was not crystal-controlled.
The transponder acts as an identification tool for aircraft allowing ATC towers to immediately recognize the identity of each plane. They work by recognizing radar frequencies as they interact with the plane. The transponder alerted by the radar responds by sending a signal of its own back to the Tower, which identifies the aircraft.