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February 1935 Short Wave Craft
 [Table
of Contents]
Wax nostalgic about and learn from the history of early electronics. See articles
from Short Wave Craft,
published 1930 - 1936. All copyrights hereby acknowledged.
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Before plug-in crystals
were widely available for band selection in radio receivers, LC tank circuits did all the
frequency discrimination heavy lifting. Accordingly, owners often had a selection
of swappable inductors on-hand to enable listening to a variety of shortwave transmissions.
During the time period of this article in a 1935 Short Wave Craft magazine, new
"all wave" radios were hitting the showroom floors that largely mitigated the need
for swapping components for the most popular frequency bands. "Short wave
listening" (SWL) was a big deal back in the day since it enabled anyone without
an amateur radio license to tune into conversations going on all over the world.
Most were content to merely listen, but many were inspired to obtain their
licenses in order to be able to transmit as well.
Here is a collection of vintage
Toute La Radio
issues (changed to Toute l'Electronique in 1962.
Improving Plug-In Coils
 By C.W. Palmer
In describing the construction of a new receiver,
a recent issue of Toute La Radio, a French magazine, included a useful
kink for improving the efficiency of plug-in-coils.
By cutting partly through the base of the coil with a hack-saw, between the various
pins which make contact with the socket, the length of insulation between pins is
increased and the amount of insulation is reduced, both of which are desirable features.
The trick shown above will considerably reduce high frequency losses in plug-in
coil forms.
Posted September 27, 2023
(updated from original post on 7/25/2017)
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