Resonant stubs in UHF transceiver 1938

Autor:

L. C. Sigmon

Shortlink:

https://czwiki.cz/b/dfe51

Zdroj:

Wikimedia Commons

Formát:

465 x 632 Pixel (41111 Bytes)

Popis:

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/

Komentář k Licence:

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:

Public domain

Credit:

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

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