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Airband or aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as VHF, or phonetically as "Victor". Different sections of the band are used for radionavigational aids and air traffic control. [1] [2] [3]
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 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 ...
Both bands (as well as 70 centimeters) were natural harmonics of the 5-meter band. Amateur privileges in the 2.5-meter band were later moved to 144–148 MHz (becoming the modern-day 2-meter band), and the old frequencies were reassigned to aircraft communication during World War II. At that time, the 1.25-meter band expanded to a 5 MHz ...
AN/PRC-103 - (Air Force) Rescue Swimmer Radio. [8] [10] AN/PRC-112 - Offers Synthesized radio in the VHF and UHF aircraft bands. A PRC-112 and a hand held GPS were used by Capt. Scott O'Grady when he was rescued after being shot down over Bosnia. [11]
Radio-controlled toys may use portions of unlicensed spectrum in the 27 MHz or 49 MHz bands, but more costly aircraft, boat, or land vehicle models use dedicated radio control frequencies near 72 MHz to avoid interference by unlicensed uses. The 21st century has seen a move to 2.4 GHz spread spectrum RC control systems.
In international aviation, SELCAL or SelCal is a selective-calling radio system that can alert an aircraft's crew that a ground radio station wishes to communicate with the aircraft. SELCAL uses a ground-based encoder and radio transmitter to broadcast an audio signal that is picked up by a decoder and radio receiver on an aircraft. The use of ...
The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies can be used for long ...