Tiedosto:Barkhausen-Kurz xmtr & rcvr 1938.png
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Barkhausen-Kurz_xmtr_&_rcvr_1938.png (661 × 406 kuvapistettä, 45 KiB, MIME-tyyppi: image/png)
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Yhteenveto
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English: An experimental 3 GHz microwave AM transmitter and receiver using a triode vacuum tube in Barkhausen-Kurz mode for both transmitting and receiving. In Barkhausen-Kurz mode the plate is biased near zero voltage while the grid is biased at a high positive voltage. The electrons oscillate back and forth through the grid, attracted by the grid and repelled by the low voltages on both the cathode and plate. The Barkhausen-Kurz was the first tube that could oscillate in the UHF range, and by the mid 30s could generate microwave frequencies. It was the only source of microwaves until the klystron was invented. The output frequency is determined by the geometry of the tube and the 4 cm half-wave antenna soldered directly to the grid terminal. The tubes and antennas are mounted at the focus of parabolic reflectors which are pointed at each other. In the receiver the Barkhausen-Kurz tube is operated below oscillation as an amplifier .
Alterations to image: Edited two images together and added label pointing out B-K tube |
| Päiväys | |
| Lähde | Retrieved March 30, 2015 from C. W. Palmer, "Transmitting and receiving on 15 cm" in Short-Wave and Television magazine, Popular Book Corp., New York, Vol. 8, No. 9, January 1938, p. 476 on http://www.americanradiohistory.com. The source said it was based on an article in a recent issue of the French magazine Toute le Radio but there is no indication that the images were from that magazine |
| Tekijä | C. W. Palmer |
| Käyttöoikeus (Tämän tiedoston uudelleenkäyttö) |
This 1938 issue of Short-Wave and Television magazine 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. Search of the Renewals for Periodicals for 1978 and later show no renewal entries for Short-Wave and Television. Therefore the copyright was not renewed and it is in the public domain. |
Lisenssi
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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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Tiedoston historia
Päiväystä napsauttamalla näet, millainen tiedosto oli kyseisellä hetkellä.
| Päiväys | Pienoiskuva | Koko | Käyttäjä | Kommentti | |
|---|---|---|---|---|---|
| nykyinen | 25. toukokuuta 2015 kello 23.51 | | 661 × 406 (45 KiB) | Chetvorno | User created page with UploadWizard |
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