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Beverage antenna
The Beverage antenna is a long wire receiving antenna mainly used in the low frequency and medium frequency radio bands, invented by Harold H. Beverage in 1921. It is used by amateur radio, shortwave listening, and longwave radio DXers and military applications.
A Beverage antenna consists of a horizontal wire from one-half to two wavelengths long (hundreds of feet at HF to several kilometres for longwave) suspended above the ground, with the feedline to the receiver attached to one end and the other terminated through a resistor to ground. The antenna has a unidirectional radiation pattern with the main lobe off the resistor-terminated end, so that end is pointed at the transmitter region. Some Beverage antennas use a two-wire design that allows reception in two directions from a single Beverage antenna. Other designs use sloped ends where the center of the antenna is six to eight feet high and both ends of the antenna gradually slope downwards towards the termination resistor and matching transformer.
The advantages of the Beverage are excellent directivity, and wider bandwidth than resonant antennas. It's disadvantages are its physical size, requiring considerable land area, and inability to rotate to change the direction of reception. Installations often use multiple antennas to provide wide azimuth coverage.
==History==
Harold H. Beverage experimented with receiving antennas similar to the Beverage antenna in 1919 at the Otter Cliffs Radio Station.〔(End of an Era: NSGA Winter Harbor to Close Its Doors )〕〔(Radio NBD, Otter Cliffs, Maine (circa 1917-1919) - from Les Smallwood, CTRCS, USN Retired )〕 He discovered in 1920 that an otherwise nearly bidirectional long wire antenna becomes uni-directional by placing it close to the lossy earth and by terminating one end of the wire with a resistor. By 1921, Beverage long wave receiving antennas up to nine miles (14 km) long had been installed at RCA's (Riverhead, New York ), (Belfast, Maine ), (Belmar, New Jersey ), and (Chatham, Massachusetts ) receiver stations for transatlantic radiotelegraphy traffic. The antenna was patented in 1921 and named for its inventor Harold H. Beverage. Perhaps the largest Beverage antenna—an array of (four phased Beverages ) three miles (5 km) long and two miles (3 km) wide—was built by AT&T in Houlton, Maine for the (first transatlantic telephone system ) opened in 1927.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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