[Lowfer] Old LF D/F Receiver

[Ed Phillips]

James Moritz wrote:
> 
> Dear LF Group, Lowfers
> 
> I recently bought a WWII vintage LF and MF receiver, which according to the
> label was "part of aircraft direction finder DZ-1", type CRV-46123,
> apparently made by RCA. Does anyone have any info on this RX?
> 
> It covers 15kHz to 1.5MHz in 6 bands, with a gap from 70kHz to 100kHz, so I
> imagine the IF is 85kHz. It has a 5 gang tuning capacitor, with separate
> input stages for loop and wire antennas, and facilities to select either or
> both antennas for non-directional, directional, or "unilateral" reception,
> with various gain and phase adjustments. The audio stages appear to have
> tuned transformers to improve selectivity. The valves are glass types,
> mainly on 6 pin bases. The tuning dial has main and vernier scales giving
> 0-1000 divisions, and there is a calibration chart on the front panel.
> 
> It is simple enough to get working without a manual, but I would be
> interested if anyone knows more about it.
> 
> Cheers, Jim Moritz
> 73 de M0BMU

	I have a DZ-1 (or DZ-2, FT-736 and other stuff piled on top of the case
and too lazy to take it off and read the label on top of the case, but
suspect the differences are trivial.  I also have, somewhere, a copy of
the schematic of the thing made a long time ago with a waxed-paper copy
process.  It was readable the last time I looked it about 20 years ago,
and probably still is.  That is actually quite a decent receiver, and I
used to use it to listen to the VVLF Navy transmissions in the 15-30 kHz
band.  The external power supply went off to other use a long time ago,
but the receiver still sits on the bench.  Used it both with a home made
loop and a long wire.  It works a lot better than my VLF Super Pro, but
doesn't have the convenience of a calibrated dial!

	If no one else comes up with any information let me know and I'll try
to move stuff around so I can get to the file cabinet in which I'm sure
the schematic resides.  As I recall it shows the complete wiring diagram
of the DF system, with connections to the loop unit.  There used to be
several of the latter floating around in LA surplus stores but suspect
they all went in the trash bin at least 40 years ago.

Ed