Soubor:Resonant stubs in UHF transceiver 1938.jpg
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Popis
| Popis |
English: Resonant stub tank lines (Lecher lines) in portable 200-300 MHz UHF vacuum tube transmitter from 1938. These were part of a backpack transceiver for remote broadcasts developed by radio station KCMO in the 30s. Each pair of parallel rods constitute a length of open-circuited transmission line. They are connected to the plate circuit of the type 955 "acorn" vacuum tube oscillator and function as a high-Q W:resonant circuit to determine the frequency of the transmitter. The lefthand one oscillates around 200 MHz, the righthand one 300 MHz. The rods are 3/8 inch solid brass, spaced 3/4 inch apart, approximately 1/8 wevelength long, tuned by a trimmer capacitor near the ends/ |
| Datum | |
| Zdroj | Retrieved April 10, 2014 from L. C. Sigmon, "A 300 and 200 Mc broadcast pack transmitter and receiver" in Communications magazine, Bryan Davis Publishing Co., New York, Vol. 18, No. 4, April 1938, p. 21, fig. 4 on http://www.americanradiohistory.com |
| Autor | L. C. Sigmon |
| Svolení (Užití tohoto souboru) |
This 1938 issue of Communication 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 1965, 1966, and 1967 show no renewal entries for Communication. Therefore the copyright was not renewed and it is in the public domain. |
Licence
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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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| současná | 24. 3. 2015, 22:45 | | 465 × 632 (40 KB) | Chetvorno | User created page with UploadWizard |
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