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Microwave signals are normally limited to the line of sight, so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter , but such systems are expensive and generally used only in ...
TD-2 was a microwave relay system developed by Bell Labs and used by AT&T to build a cross-country network of repeaters for telephone and television transmission. The same system was also used to build the Canadian Trans-Canada Skyway system by Bell Canada , and later, many other companies in many countries to build similar networks for both ...
These military systems were some of the first practical microwave relay systems and presaged development of the great transcontinental commercial microwave relay networks in the 1950s. The systems shown here were: AN/TRC-1, 70-100 MHz FM system carries 4 telephone circuits; AN/TRC-5, 230-250 MHz FM system carries 4 phone circuits
The British Army's Wireless Set, Number 10, was the world's first multi-channel microwave relay telephone system. [1] It transmitted eight full-duplex (two-way) telephone channels between two stations limited only by the line-of-sight, often on the order of 25 to 50 miles (40 to 80 km).
A telecommunications tower with a variety of dish antennas for microwave relay links on Frazier Peak, Ventura County, California. The apertures of the dishes are covered by plastic sheets to keep out moisture. Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves.
A typical larger microwave antenna designed for mid to long range A parabolic satellite antenna for Erdfunkstelle Raisting, based in Raisting, Bavaria, Germany. C band horn-reflector antennas on the roof of a telephone switching center in Seattle, Washington, part of the U.S. AT&T Long Lines microwave relay network.
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Networks of microwave relay stations transmit telephone calls, television programs, and computer data from one city to another over continent-wide areas. Passive repeater: This is a microwave relay that simply consists of a flat metal surface to reflect the microwave beam in another direction. It is used to get microwave relay signals over ...