File:Troposcatter corner reflector antenna 1955.jpg

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Summary

Description	English: A large VHF corner reflector antenna built in 1955 for a US military tropospheric scatter (troposcatter) communications system, from an advertisement in an electronics magazine. The antenna, 120 feet high and 130 feet wide, consists of two corner reflectors, facing to the left rear, each consisting of two flat reflecting planes made of a grill of horizontal wires at a 90 degree angle, with a line of dipole driven elements in front of them. Before the advent of communications satellites in the mid 1960s, troposcatter was developed by the military as a reliable long distance communication technique. The antenna was located in South Dartmouth, Massachusetts, USA and communicated with Cedar Rapids, Iowa, 1100 miles away. It beamed a powerful beam of radio waves at a shallow angle above the horizon. Radio waves of this frequency are not reflected by the ionosphere like lower frequency waves, but a tiny amount of the energy is scattered by water vapor in the troposphere. A sensitive receiver in Cedar Rapids with a directional antenna pointed at the point where the beam passed through the troposphere received the scattered waves. Alterations to image: cropped out advertising copy in top right of image and cloned sky texture over the area. Part of advertising copy: Gigantic antenna unveiled . . . one of the world's largest antennas. This gigantic VHF antenna stands 120 feet high and is 130 feet wide. Located in South Dartmouth, Mass. it transmits to Cedar Rapids, Ia. - 1100 miles away - and is a vital link in our radar defense system. The smaller "dish" antennas are 28 feet in diameter
Date	October 1955
Source	Retrieved May 25, 2015 from Tele-Tech magazine, Caldwell-Clements Inc., New York, Vol. 14, No. 10, October 1955, p. 129 on http://www.americanradiohistory.com
Author	Unknown authorUnknown author
Permission (Reusing this file)	This image is from an advertisement by D. S. Kennedy and Co. without a copyright notice published in a 1955 magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain.

Licensing

This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.

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