File:Experimental 60MHz Lecher line transmitter 1934.jpg
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English: An experimental 60 MHz amateur radio transmitter using a Lecher line tank circuit, built by radio amateur George W. Shuart, W2AMN, in 1934. During the 1930s VHF and UHF frequencies were the frontier in shortwave research. It was difficult to get ordinary vacuum tubes to work at such high frequencies because of electrode capacitance and inductance. This oscillator uses a triode vacuum tube with two coupled shorted Lecher lines (parallel transmission line stubs) attached to the grid and plate circuit to act as the resonator. The frequency could be changed by sliding the shorting bar up or down the line, as Mr. Shuart is doing. |
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| Source | Retrieved March 21, 2014 from George W. Shuart, "New High Impedance Lines Replace Coils" in Short Wave Craft, Popular Book Corp., New York, Vol. 5, No. 6, October 1934, p. 332, fig. 2 on American Radio History] website |
| Author | George W. Shuart |
| Permission (Reusing this file) |
This 1934 issue of Short Wave Craft magazine would have the copyright renewed in 1962. 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 1961, 1962 and 1963 show no renewal entries for Short Wave Craft. Therefore the magazine's copyright was not renewed and it is in the public domain. |
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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.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
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| current | 08:29, 22 March 2014 | | 570 × 685 (62 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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