File:Umbrella antenna 1910.png
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| Description |
English: An umbrella antenna, a monopole antenna used for LF transmitting, at the longwave wireless telegraphy station of the Amalgamated Radiotelegraphic Co. at Cullarcoats, on the Northumberland coast near Newcastle, England in 1910. It consists of a 220 ft wooden lattice tower with two wires running from the transmitter in the building to the top, connected at the top to 24 bronze wires extending radially from the mast on a diagonal, attached to ropes which are anchored to the ground on a circle 220 ft in radius. The vertical wires served as an electrically short quarter-wave monopole antenna while the radial wires served as a capacitive "top hat" to increase the current in the vertical radiators. The other side of the transmitter was connected to a ground (Earth) system consisting of buried cables radiating from the base of the mast. It transmitted with both a spark gap transmitter and a Poulsen arc transmitter on a frequency of 200 kHz. |
| Date | |
| Source | Retrieved February 17, 2015 from John Ambrose Fleming (1910) The Principles of Electric Wave Telegraphy and Telephony, 2nd Ed., Longmans, Green and Co., New York, p. 797, fig. 16 on Google Books |
| Author | John Ambrose Fleming |
| Permission (Reusing this file) |
Fleming died in 1945. |
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This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 70 years or fewer. 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. |
| This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights. | |
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| current | 01:02, 20 October 2015 | | 771 × 593 (48 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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