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File:Experimental Westinghouse 3GHz microwave transmitter 1933.jpg

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Experimental_Westinghouse_3GHz_microwave_transmitter_1933.jpg ‎(530 × 486 pixels, file size: 89 KB, MIME type: image/jpeg)

Summary

Description
English: An experimental 3.3 GHz microwave radiotelephone transmitter developed by scientist Ilia E. Mouromtseff at Westinghouse laboratories in 1933. It was demonstrated at the 1933 Chicago World's Fair. During the 1930s the first low power vacuum tubes capable of generating microwaves were invented. The microphone converts the voice of the man into a varying audio frequency alternating current. The audio modulates the microwaves generated by a small tube at the focus of the shiny parabolic reflector. The microwaves are reflected by the parabolic reflector into a beam, which travels to a receiver several miles away, which converts the electric signal back into sound. The radiated power was about 1 watt.
Date
Source Retrieved 26 August 2024 from Mouromtseff, I. E. "3.5 inch Waves Now Practical" in Short Wave Craft magazine, Popular Book Corp. Vol.4, No.5, September 1933, p.267 on https://www.worldradiohistory.com
Author I. E. Mouromtseff (died 19 May 1954)
Permission
(Reusing this file)		 This 1933 issue of Short Wave Craft magazine would have the copyright renewed in 1961. 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 1960, 1961, and 1962 show no renewal entries for Short Wave Craft. Therefore the copyright was not renewed and it is in the public domain.

Licensing

Public domain
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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Public domain

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Captions

Experimental microwave transmitter

File history

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Date/TimeThumbnailDimensionsUserComment
current14:46, 26 August 2024Thumbnail for version as of 14:46, 26 August 2024530 × 486 (89 KB)ChetvornoUploaded a work by I. E. Mouromtseff from Retrieved 26 August 2024 from [https://www.worldradiohistory.com/Archive-Short-Wave-Television/30s/SW-TV-1933-09.pdf#search=%22mouromtseff%20ultra-short%20waves%22 Mouromtseff, I. E. "3.5 inch Waves Now Practical" in ''Short Wave Craft'' magazine, Popular Book Corp. Vol.4, No.5, September 1933, p.267] on https://www.worldradiohistory.com with UploadWizard
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