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Antennas of 1931 experimental 1.7 GHz microwave relay link across the English Channel. The receiving antenna (background, right) was located behind the transmitting antenna to avoid interference. US Army Signal Corps portable microwave relay station, 1945. Microwave relay systems were first developed in World War II for secure military ...
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 ...
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.
The second segment of White Alice was a pair of TD-2 microwave radio links that supported the Ballistic Missile Early Warning System (BMEWS) at Clear Air Force Station. This section provided two routes from Alaska to NORAD in Colorado, for this reason it was also known as the Rearward Communications System . [ 3 ]
The first experimental microwave relay system, a 1.7 GHz link 40 miles across the English channel in 1931, used a Barkhausen-Kurz tube mounted at the focus of the 10 foot dish shown. It had a radiated power of about 1/2 watt.
The entire system carried its first signals on 18 June 1958, and was declared officially operational on 1 July, Dominion Day. [7] Stretching 6,400 km from Sydney, Nova Scotia to Victoria, British Columbia, it was the longest microwave relay in the world. [6] [7] It was further extended to Newfoundland in 1959. [12]
The first complete system was installed between New York and Chicago and opened on September 1, 1950. Given the cold war period in which the microwave relay system was designed, the AT&T Long Lines network was engineered to survive a nuclear attack.