On Fri, 10 Oct 2008, COLIN LAMB wrote:

A BC-453 tunes 455 kHz and converts to 85 kHz. The selectivity can be
increased by pulling out the plastic inserts. Audio is high impedance, but
can be used to feed into another audio amp or back into the receiver audio
chain. Lots of info available on the internet. Today, it is easy to build
a 24 volt supply, and they like that.

Used to be $4.95 - oh wait, that was 1959. But they are still available.

But are they still cheap?

I bought my one and only Command Set transmitter in 1972, for ten
dollars here in Canada. It was actual surplus, rather than bought
from someone who'd bought it surplus.

It's now been longer since I bought it than 1972 was from the end of
WWII.

Michael VE2BVW

Build a double conversion converter and you can tune a few hundred kHz. Or
build a converter with a synthesized oscillator. Makes a great mobile
receiver for your 1954 Buick Special. Build a solid state inverter onto
that dynamotor plate. In fact, you can use one of those cheap $6 12 - 120
volt inverters and use a voltage doubler to get the correct voltage.

Colin K7FM