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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 ...
The wireless communication is typically bi-directional and either time-division multiple access (TDMA) or channelized. This can be a microwave relay link consisting of a transmitter which transmits a narrow beam of microwaves with a parabolic dish antenna to a second parabolic dish at the receiver.
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 ...
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 ...
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).
Microwave technology advanced during World War 2 due to the development of radar, and toward the end of the war the US Army began using microwave communication systems in the European theater. These military systems were some of the first practical microwave relay systems and presaged development of the great transcontinental commercial ...
Normally, signals in the microwave frequency range travel in straight lines, and so are limited to line-of-sight applications, in which the receiver can be 'seen' by the transmitter. Communication distances are limited by the visual horizon to around 48–64 kilometres (30–40 mi). Troposcatter allows microwave communication beyond the horizon.
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.