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An avalanche transceiver or avalanche beacon is a type of emergency locator beacon, a radio transceiver (a transmitter and receiver in one unit) operating at 457 kHz for the purpose of finding people buried under snow. They are widely carried by skiers, particularly back country skiers for use in case a skier is buried by an avalanche.
Hawes Radio Relay Facility (also known as the Hawes Radio Tower) was a United States Air Force installation built on the site of the former Hawes Airfield [1] at Hinkley, California, USA at The site contained a 373.7-meter-tall (1,226 ft) guyed mast antenna and hardened underground facility used for the Strategic Air Command 's AN/FRC-117 ...
Avalanche airbag system with visible airbags. Avalanche airbags help a person avoid burial by making the user an even larger object relative to the moving snow, which forces the person toward the surface. Avalanche airbags work on the principle of inverse segregation (granular convection). [8]
ALLISS is a somewhat rotatable antenna system for high power shortwave radio broadcasting in the 6 MHz to 26 MHz range. An ALLISS module is a self-contained shortwave relay station that is used for international broadcasting .
The typical AN/ARC-5 three-receiver, two-transmitter installation reflects system capabilities that are quite sophisticated compared to the earlier systems, allowing VHF homing, four channel VHF-AM communications, and one channel MF/HF-AM communications. All unnecessary controls have been eliminated to simplify operation of this more capable ...
A new form of omnidirectional satellite antenna, which does not use a directed parabolic dish and can be used on a mobile platform such as a vehicle was announced by the University of Waterloo in 2004. [12] The theoretical gain (directive gain) of a dish increases as the frequency increases. The actual gain depends on many factors including ...
The antenna used for broadcasting through the 1920s was the T-antenna, which consisted of two masts with loading wires on top, strung between them, requiring twice the construction costs and land area of a single mast. [2] (pp 77–78) In 1924 Stuart Ballantine published two historic papers which led to the development of the single mast antenna.
In addition to the HFGCS, U.S. aircraft frequently use Military Auxiliary Radio System (MARS) HF stations (13927.0 kHz) and Canadian Forces HF stations (11232.0 kHz) to relay messages. Various other discrete frequencies are available, and used, as part of the HFGCS network and are not listed here. Recording of an EAM on the 11175 kHz HFGCS system.