Crystal_radio_receiver_from_wireless_era.png
Summary
Description Crystal radio receiver from wireless era.png |
English:
Early
crystal radio receiver
built by a radio amateur in Belfast, Ireland, during the pioneering
wireless telegraphy
era of radio around the first decade of the 20th century, showing examples of the early electronic components used. From a 1914 radio book. This example is a sophisticated inductively-coupled type, with an air-core antenna coupling transformer (called a
loose coupler
) to improve selectivity (Q factor) by adjusting the inductive coupling. This was used to receive long wave (148 - 283 kHz)
radiotelegraphy
broadcasts. Alterations to image: Added colored labels. The labelled parts are identified on p. 264 of the source text as:
(1)
Adjustable antenna coupling transformer, called a "loose coupler". The secondary coil, visible on the right, slides in and out of the primary coil in the box, to adjust the coupling of the antenna to improve selectivity. The switches on the front of the box select taps on the coil to adjust the impedance match between the antenna and the receiver
|
Date | |
Source | Downloaded 2009-11-14 from Rupert Stanley (1914) Textbook on Wireless Telegraphy, Vol. 1 , Longmans Green & Co., New York, p.265, fig. 151 on Google Books |
Author | Rupert Stanley |
Permission
( Reusing this file ) |
Public domain in USA - published in USA prior to 1923 |
Licensing
Public domain Public domain false false |
This media file is in the
public domain
in the
United States
. This applies to U.S. works where the copyright has expired, often because its first
publication
occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See
this page
for further explanation.
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This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the
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Annotations
InfoField
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This image is annotated: View the annotations at Commons |
Primary (antenna) tuning capacitor, 8 pF max, only used on lower part of band.
Adjustable antenna coupling transformer, called a "loose coupler". The secondary coil, visible on the right, slides in and out of the primary coil in the box, to adjust the coupling of the antenna to improve selectivity. The switches on the front of the box select taps on the coil to adjust the impedance match between the antenna and the receiver.
Earphones, electromagnetic type, 8000 ohm
Spare crystal detector.
Crystal detector, "Perikon" (zincite-chalcopyrite junction) type.
Secondary tuning capacitor.
Blocking capacitor, 8 pF.
Antenna loading coil, 15 mH, only used on lower part of band.