File:Vacuum tube HF300 shortwave RF power amplifier from 1938.jpg
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Vacuum tube RF power amplifier
Summary[edit]
| Description |
English: A vacuum tube RF final amplifier for a radiotelegraphy shortwave amateur radio transmitter from 1938. It uses two T200 or HF300 triode tubes in a push-pull circuit. It could produce 1 kW with 1200 volts on the plates. The two homemade sheet metal capacitors between the tubes were for neutralization of the grid-plate capacitance to prevent parasitic oscillations. |
| Date | |
| Source | Retrieved 7 June 2023 from Smith, W. W. 1938 The Radio Handbook, Radio, Ltd., Los Angeles, p.343 fig.24 on archive.com |
| Author | W. W. Smith |
| Permission (Reusing this file) |
This book published in the US in 1938 would have the copyright renewed in 1966. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here [1]. Search of the Renewals for Periodicals for 1965, 1966 and 1967 show no renewal entries for The Radio Handbook. Therefore the work's copyright was not renewed and it is in the public domain. |
Licensing[edit]
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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 | 23:19, 7 June 2023 | | 383 × 627 (90 KB) | Chetvorno (talk | contribs) | Uploaded a work by This book published in the US in 1938 would have the copyright renewed in 1966. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here [http://onlinebooks.library.upenn.edu/cce/]. Search of the Renewals for Periodicals for 1965, 1966 and 1967 show no renewal entries for ''The Radio Handbook''. Therefore the work's copyright was not renewed and it is in the public domain. from Retrieved 7 June 2023 from [https://archiv... |
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