Impoverished Radio Experimenter #4
Some
people think store bought is always better. Even when talking about radios.
Some guys think you could never build a regenerative receiver as good as the
National's old SW-3, for instance. That's bunk. You should be able to build
something every bit as good, if not better. And the ideas needed to do that
are here.
First,
we start out with a demonstration receiver that will hit you with many ideas,
some of which you'll want to try. 
This
receiver is a four tube regenerative with an RF amplifier (TRF). The original
configuration uses two audio tubes with audio filter in the back end to drive
headphones, but the filter turned out to be more selective than needed. The
second version uses a simpler audio filter, and the second audio tube is replaced
by a power tube that will drive a loudspeaker to surprising volume. You'll
see how a National PW dial drive is mounted upside down for breadboard use,
how "plug-in" coil forms are fabricated, and more.
Next, the shortwave converter 
idea
of Vol 3 is taken to next step: a
modern tube and a crystal controlled oscillator. When this unit was put in
front of the TRF receiver, 15 meter (21 mhtz) amateur band signals came flooding
in from all over the planet, loud, stable, and distinct. The two units together
with a simple tube transmitter could put you on the higher DX bands.
Then to make tube experimentation easier and larger projects possible, we build a quality power supply capable of providing a wide range of voltages at high current levels.
Finally
we explore slide rule dials. These simple, inexpensive fabrications of string
and pulleys were used in millions of old broadcast radios, and they worked
beautifully. You'll see how one was built from aluminum plate and simple pulleys
that could be mounted on a homebuilt receiver. The result is a slow motion
dial drive with a long bandspread dial that makes your homebuilt receiver
fun to use and will impress the socks off your half-wit relation.
More useful ideas for the radio builder. With schematics, drawings, and photos. Jam-packed like the first three volumes. Get a copy! 5-1/2 x 8-1/2 booklet 48 pages
No. 22920 ...$6.95
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