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

[Bob Camp]

Hi

I'm not sure the issue went away with the regen era. The specifications 
certainly are still with us today. They have also made it over into the 
commercial side of things. This is particularly true in the European 
countries.

Of course after the Verona stuff the whole Tempest world got a lot more 
intensive ....

	Take Care!

		Bob Camp
		KB8TQ


On Jun 28, 2004, at 3:12 PM, antqradio at juno.com wrote:

> 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
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