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  • 21 Aug, 2019

  • By, Wikipedia

File:Marconi Parabolic Xmtr And Rcvr 1895.jpg
The frequency of radio waves produced would have been in the UHF range, several hundred megahertz, roughly the frequency now used by television stations. Marconi found that using parabolic antennas increased the transmission distance greatly compared to his earlier plain dipole antennas.

Caption of left image: This picture shows a very early model transmitter, invented by Marconi for short-wave beam-radio work.
Caption of right image: Marconi's early model receiver for focusing the signals from beam trasmission, designed by him in 1895.

Alterations to image: combined two separate images from source page.
Date Source Retrieved July 16, 2016 from H. F. Breckel, "The Radio Beam Method of Transmission" in Radio News magazine, Vol. 9, No. 7, October 1927, p. 324 on http://www.americanradiohistory.com Author Unknown authorUnknown author Permission
(Reusing this file) This 1927 issue of Radio News magazine would have the copyright renewed in 1955. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. Search of the Renewals for Periodicals for 1954, 1955 and 1956 show no renewal entries for Radio News. Therefore the magazine's copyright was not renewed and it 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. 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 (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.

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Date/TimeThumbnailDimensionsUserComment
current14:53, 3 May 2021Thumbnail for version as of 14:53, 3 May 2021559 × 295 (79 KB)MaterialscientistFFT
23:52, 16 July 2016Thumbnail for version as of 23:52, 16 July 2016559 × 295 (46 KB)ChetvornoUser created page with UploadWizard
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