[Milsurplus] ATD

[Hue Miller]

Dave, why not get an RU just for display purposes with the Jeep, 
but only keep 2 or 3 coils for it.  When running the Jeep, on AM,
you need a better AM receiver, so you could use an ARB in a 
"Fantasy Installation".  As Mike H. pointed out, the ARB was 
intended as an identical-footprint replacement for the RU. Who's
to say it was never flown together with the GP ? ( Even if only
in YOUR ship, hi )
It occurred to me, that to get better selectivity from the RU, one
might (1) use a small converter to convert down to the 400-500
kcs. range, or (2) since that wouldn't get you that great selectivity
with its only 3 circuits, one might devote this receiver only to
CW, by backing off the bias on the biased detector, so it works
more as a product detector, or (3) add some selectivity by means
of a 2-terminal  oscillator connected as a Q-multiplier into the
RU, with control via an external pot in a small accessory box.
( Q mult uses the receiver tuned circuit, so it always "tracks". )

I also wonder if the ATD might be acting "squirrelly" on 20m
with that band switching arrangement.   -Hue Miller