[Milsurplus] Re: DFing receiver re-radiation in WW 2?

[antqradio at juno.com]

I think that all of this concern for receiver (and by extension, local
oscillator) radiation is "boiler plate" left over from regenerative
receivers used prior to WW2.  The evidence for this comes from the
history of the Signal Corps which mentioned that the BC-312 was the first
superhetrodyne receiver in inventory.  That puts it in the field by the
late 1930s.  Not much time for the specs to be modified or updated before
rearmament and building all of those mil receivers.
Just an observation,
Jim

On Mon, 28 Jun 2004 13:41:09 -0400 "Richard Brunner" <rbrunner at gis.net>
writes:
> Re:
> > .................Did the US or its enemies have special gear for 
> DFing
> receiver reradiation? I really doubt that standard DF gear would do 
> the job.
> ............."
> 
> I have never seen special gear for DF'ing receiver radiation, nor found
> evidence that anyone did.  I have corresponded with Germans on this
point,
> and they never bothered, as they had better reliable resources.  Their
> underwater listening gear could hear ship's screws at minimum 20 miles
away.
> When a sub found a convoy it would sometimes, upon request, broadcast a
weak
> beacon for other subs to home on.  I have found no reference to special
> equipment, so the sub's beacon would be standard equipment at reduced
> output, certainly measured in Watts, vs milliwatts or microwatts from a
> receiver.
> 
> "The Metox Affair"  The Germans had a vhf receiver, the Metox, made in
> France, to detect radar, and when they were routinely caught on the
surface
> with no radar warning, they suspected we were homing on Metox's
receiver
> radiation.  This was plausible because it used a 955 local oscillator
and no
> rf stage.  They then conducted tests by flying a plane with a vhf
receiver
> over at various altitudes, and found that receiver radiation could
indeed be
> detected at respectable distance depending on altitude.
> 
> 500 m       12 sea miles/22 km
> 1,000 m    18 sea miles/33 km
> 2,000 m    25 sea miles/46 km
> 
> They then pulled the Metox receivers from service.  We were not
listening,
> rather had moved to microwave radar, which was undetectable on the 
Metox.
> 
> Reference: "Funkpeilung als alliierte Waffe gegen deutsche U-Boote
> 1939-1945," Arthur Bauer, 1997
> Their "955" has, I think, a different number, but is the same 
> construction.
> I have the Metox schematic here somewhere.
> 
> Richard Brunner, AA1P