Crystal radio tuning coil



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English: Tuning coil used in early crystal radios from a 1914 radio book. This was called a "two slider" coil because it had two adjustable contacts that slid up and down the coil. In a crystal radio receiver, one was used to tune the receiver to different stations, while the other was used to adjust the antenna impedance matching.
Date 1914(1914)
Source Downloaded 2010-02-08 from Alfred Powell Morgan (1914) Wireless Telegraph Construction for Amateurs, 3rd Ed., D. Van Nostrand, New York, p.151, fig. 124 on Google Books
Author Alfred Powell Morgan
(Reusing this file)

Public Domain in USA - published prior to 1923 in USA


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