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Axial, prime focus, or front feed – This is the most common type of feed, with the feed antenna located in front of the dish at the focus, on the beam axis, pointed back toward the dish. A disadvantage of this type is that the feed and its supports block some of the beam, which limits the aperture efficiency to only 55–60%.
The AN/FPS-133 Air Force Space Surveillance System, colloquially known as the Space Fence, was a U.S. government multistatic radar system built to detect orbital objects passing over America. It is a component of the U.S. space surveillance network , and according to the U.S. Navy was able to detect basketball sized (75 cm (30 in)) objects at ...
The company was founded in 1923 by Edgar F. Johnson and his wife Ethel Johnson. The company began as a mail order business, selling radio transmitting parts to amateurs and early radio broadcasters from space shared with a woodworking shop located in downtown Waseca. In 1936, E.F. Johnson Co. built its first factory and office building in ...
Commercial FM broadcasting transmitter at radio station WDET-FM, Wayne State University, Detroit, US.It broadcasts at 101.9 MHz with a radiated power of 48 kW.. In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna with the purpose of signal ...
As a crystal radio has no power supply, the sound power produced by the earphone comes solely from the transmitter of the radio station being received, via the radio waves captured by the antenna. [3] The power available to a receiving antenna decreases with the square of its distance from the radio transmitter. [46]
VHF transmitter T-23/ARC-5 and HF transmitter T-20/ARC-5 on rack MT-71/ARC-5. The AN/ARC-5 Command Radio Set is a series of radio receivers, transmitters, and accessories carried aboard U.S. Navy aircraft during World War II and for some years afterward.
The AN/PRC-77 entered service in 1968 during the Vietnam War as an upgrade to the earlier AN/PRC-25.It differs from its predecessor mainly in that the PRC-77's final power amplifier stage is made with a transistor, eliminating the only vacuum tube in the PRC-25, as well as the DC-DC voltage converter used to create the high plate voltage for the tube from the 15 V battery.
An infinity transmitter (also known as a harmonica bug) is a surveillance device used to covertly monitor conversation in a room through a telephone line. Its name derives from the fact that, by using a telephone line as a transmitter, it can work at an infinite distance, unlike other bugging devices that have only a finite signal range. [ 1 ]