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main mast of Shaanxi No.10 Transmitting Station, Chunhua, Xianyang, Shaanxi, China: May 2, 1982 [10] Guyed steel lattice mast 129 [11] High winds and corrosion Senior Road Tower, Missouri City, Texas, US December 7, 1982: Guyed steel lattice mast 569 Guy support wire severed Total collapse during installation of 6-ton FM antenna on new 1800 ft ...
Typical distances are between 50 and 250 kilometres (31 and 155 mi), though greater distances can be achieved depending on the climate, terrain, and data rate required. Typical antenna sizes range from 1.2 to 12 metres (3 ft 11 in to 39 ft 4 in) while typical amplifier sizes range from 10 W to 2 kW.
Although no real antenna can be exactly isotropic, a few antennas are built to be as near to isotropic as possible; they are used for emergency backup antennas and for test equipment for other antennas: Because the received and transmitted signal strength is the same in (almost) every direction, they work without any need for them to be any ...
Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site above the surrounding landscape. HAAT is used extensively in FM radio and television , as it is more important than effective radiated power (ERP) in determining the range of broadcasts ( VHF and ...
A beam waveguide antenna is a type of complicated Cassegrain antenna with a long radio wave path to allow the feed electronics to be located at ground level. It is used in very large steerable radio telescopes and satellite ground antennas, where the feed electronics are too complicated and bulky, or requires too much maintenance and alterations, to locate on the dish; for example those using ...
The Tarheel Army Missile Plant was constructed in 1927 as a synthetic fabric rayon manufacturing plant for the A.M. Johnson Rayon Mills, Inc. The company failed in marketing their rayon product to the textile weaving plants in the Burlington vicinity. As a result, the plant was renamed the Carolina Rayon Mills, Inc and a new management was ...
The North Tower of the original World Trade Center also had a 110-metre (360 ft) telecommunications antenna atop its roof, constructed in 1978–1979, and began transmission in 1980. When the buildings collapsed, several local TV and radio stations were knocked off the air until backup transmitters could be put into service. [ 13 ]
An antenna array consisting of two such antennas, one above the other and driven in phase has a gain of up to 17 dBi. Being log-periodic, the antenna's main characteristics ( radiation pattern , gain, driving point impedance ) are almost constant over its entire frequency range, with the match to a 300 Ω feed line achieving a standing wave ...