File:Counterpoise.jpg
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| Description |
English: A counterpoise, a network of wires suspended above the ground under a transmitting radio antenna, which functions as a ground connection for the transmitter. The counterpoise consists of "star" of radial copper wires extending from the base of the antenna mast, connected at the center to the "ground" side of the radio transmitter. It is used in medium wave and longwave radio transmitters when a low resistance ground connection cannot be constructed because of high soil resistance. The counterpoise functions as a large capacitor plate, with the conductive ground layers as the other plate. In this example the ends of the radial wires are attached to a circular nonconductive cord supported by insulators from a ring of poles. The counterpoise is suspended high enough so that maintenance personnel can walk under it to reach the helix house feed enclosure located at the base of the antenna under the counterpoise. The radial counterpoise wires should be about a quarter wavelength long if possible, and should not be electrically connected at the periphery, to prevent eddy currents from flowing in the loops which waste energy. Alterations to image: Added two labels, "INSULATING SUPPORT" and "RADIAL WIRE" to the image to improve explanation |
| Date | |
| Source | Retrieved from Edmund A. Laport, Radio Antenna Engineering, McGraw-Hill Publishing Co., New York, 1952, p. 53, fig. 1.14 on David Platt's webpage for this book |
| Author | Edmund A. Laport |
| Permission (Reusing this file) |
The copyright for this book Radio Antenna Engineering should have been renewed in 1980. A search of the US Copyright Office online database covering 1978 to the present shows no copyright renewal for that author name or title. Therefore the copyright was not renewed and the book is in the public domain. |
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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
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| current | 16:35, 18 March 2014 | | 623 × 555 (59 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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