File:Flattop antenna 1912.png
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DescriptionFlattop antenna 1912.png |
English: A triatic or "flattop" antenna, a type of "inverted L" wire antenna used in high power very low frequency transmitting stations, particularly the longwave radiotelegraphy stations during the wireless era up until the mid 1920s. It consists of multiple wires (from 7 to 30) extending from the transmitter in the building up to a series of tall steel towers where they ran parallel to the ground for distances up to a mile. It was used for transoceanic transmitters at frequencies from 300 kHz to 20 kHz. Antennas at these frequencies are very electrically short, a small fraction of a wavelength high, and therefore inefficient radiators. It functioned as a capacitively loaded monopole antenna; the vertical section was the main radiator, while the horizontal section acted as a capacitive top load, increasing the current in the vertical section to increase the radiated power. There is a ground system consisting of radial buried cables under the antenna, connected to the other side of the feedline. |
Date | |
Source | Retrieved 9 February 2018 from Charles Grinnell Ashley and Charles Brian Hayward (1912) Wireless telegraphy and wireless telephony: an understandable presentation of the science of wireless transmission of intelligence, American School of Correspondence, Chicago, IL, p. 57, fig. 42 on Google Books |
Author | Charles Grinnell Ashley and Charles Brian Hayward |
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Public domainPublic domainfalsefalse |
This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1929.
Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country.
Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Flattop_antenna_1912.png |
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current | 19:33, 17 February 2018 | 888 × 524 (68 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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File change date and time | 01:21, 11 February 2018 |