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

[D C Macdonald]

I would guess that, as in many cases during WW II, facts had very
little to do with action being taken in response to possible threats,
real  OR  imagined.

It's sort of like having air raid drills in the middle of the afternoon
when there was no possible way for either German or Japanese
aircraft to reach 400 miles from the nearest ocean, to say nothing
about a direct launch from either of those countries!

It was probably as much a psychological ploy to convince the
general population that they were actually participating in the
overall war effort.  To that end, the drills were most probably
beneficial except for the minority that realized it was stupid!

73  ---  Mac, K2GKK/5


----Original Message Follows----
From: BOEING377 at aol.com
To: milsurplus at mailman.qth.net
Subject: [Milsurplus] Re: DFing receiver re-radiation in WW 2?
Date: Mon, 28 Jun 2004 11:41:26 EDT

There was apparently a lot of concern in WW 2 about receivers radiating
signals that would give away their presence and possibly allow direction 
finding by
enemies.  Some had special circuits to suppress such radiation before it
could reach the antenna (e.g., ARR 7).  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 had lots of experience with ARN 7 Radio Compass eqpt as
well as later commercial marine DF gear and it took a reasonably strong 
signal to
give a trackable null.  I don't doubt that you could detect a relatively low
powered radiated IF signal at some distance, but DFing it with a small loop
seems doubtful to me unless you were very very close.