[Milsurplus] Getting Those Ferrying Command Radios OTA.

[David Stinson]

Ya'll know that the little Ferrying Command and WASP radios
are a special interest of mine.  I have several complete sets 
and would like to use them on the air. 
Most of these sets transmit on 3 MC, but receive on Longwave.  
So I finally got enough time to work out 
the kinks in a simple converter that will allow me to use the sets
on the "AM Ghetto" of 3880-3890 KC.

The converter uses a color burst xtal to bring 3880 KC down to 
about 300 KC.  It only has one tuned circuit, so images from the 
3 MC broadcast band are in there, but they aren't a big enough 
problem to warrant spending the few minutes I get to tinker
fighting them.  This level of images is a fair trade-off for 
time and simplicity.   Besides- listening to the preacher rants 
and CHU are fun, and the "AM Ghetto" is clear of images.
Here's the circuit:

http://home.netcom.com/~arc5/converter.JPG

If you prefer no images, you can build a better input circuit.
If you do, let us know how you come out.
The hardest part was getting the input coil and cap right.
Grid dipper and spec analyzer did the trick.

If you decide to build the converter, you can adjust the 
B+ input resistor for whatever voltage you have.
If 6-volts, run it direct without the resistor.
If 24 volts, you'll need to go higher (I haven't tried that yet).
Use a 10K pot or something and go up slowly, because
voltages over about 9 will zap the chip.  If you have NE602,
SA602 or SA612, they will all work and are identical for hook-up.
I run the +12 volt input through my PTT circuit, so it turns the 
converter off  during transmit.
Next step is to convert a 150 watt CB "Lean-Yar"
brick to 75 meters.  Not all that hard, with this one.  
Perhaps you will be hearing my 150 watt WASP radio soon :-).

73 Dave S.