151:, constructed by James Millen in 1933. During the 1930s the frontier in radio research was the UHF wavelengths. Ordinary vacuum tube feedback oscillators would not reach these frequencies due to electrode capacitance and inductance. The Barkhausen-Kurz oscillator, the first transit time oscillator, was the first circuit which could produce power at UHF frequencies. It used a specially designed triode tube in which the electrons, instead of moving from cathode to plate, oscillated back and forth between cathode and plate through the grid, which was biased at a high voltage. The transmitter uses two coupled
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in front of the parabolic reflector, is fed by another parallel line. Millen is using another Lecher line to measure the output frequency. This transmitter radiated 5 W at 300-400 MHz.
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magazine would have the copyright renewed in 1961. Online page scans of the
Catalog of Copyright Entries, published by the US Copyright Office can be found here.
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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
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for US works (depending on the date of the author's death), such as Canada (70 years
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Note that it may still be copyrighted in jurisdictions that do not apply the
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184:, Popular Book Corp., New York, Vol. 3, No. 11, March 1933, p. 648, fig. 3
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James Millen, "Experimental 3/4 Meter
Transmitters and Receivers" in
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Click on a date/time to view the file as it appeared at that time.
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UHF Barkhausen-Kurz Lecher line transmitter 1933 closeup.jpg
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Add a one-line explanation of what this file represents
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UHF Barkhausen-Kurz Lecher line transmitter 1933.jpg
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Commons is a freely licensed media file repository.
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
