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

[Radioman390 at cs.com]

In a message dated 6/28/04 12:06:10 PM Eastern Daylight Time, 
BOEING377 at aol.com writes: 
> 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. 

A TV ratings company introduced a truck which would drive down the street and 
could tell what TV channel was being watched by its radiated signal (local 
oscillator?).

Another ratings firm put up receivers alongside roadways to measure in-car 
audiences. Although with many $300 Toyotas with $4000 sound systems, your ears 
will do a good job in IDing the station, even from afar.

Currrently, low radiation devices are required in many applications; the 
standard is called "Tempest"