File:George Southworth & waveguides.jpg
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Summary
| Description |
English: American electrical engineer George C. Southworth of Bell Telephone Laboratories, who in 1933 helped invent the waveguide, a metal pipe that carries radio waves. He is standing in front of two experimental prototype waveguide lines that were used in some of the original research on waveguide modes in the 1930s. He is holding a microwave cavity resonator. |
| Date | |
| Source | Retrieved March 23, 2015 from Radio-Craft magazine, Radcraft Productions, Springfield, MA, Vol. 14, No. 9, June 1943, p. 525 on http://www.americanradiohistory.com |
| Author | Unknown author |
| Permission (Reusing this file) |
This 1943 issue of Radio-Craft magazine would have the copyright renewed in 1971. 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 1970, 1971, and 1972 show no renewal entries for Radio-Craft. Therefore the copyright was not renewed and it is in the public domain. |
Licensing
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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/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 07:35, 24 March 2015 |  | 640 × 623 (91 KB) | Chetvorno | User created page with UploadWizard |
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