[Milsurplus] E. H. Scottr RCH or SLR-F?

[mikea]

On Tue, Jun 01, 2004 at 12:58:28PM -0500, Dave Merrill wrote:
> Suppose local oscillator radiation is the basis of this technology?
> Hard to see how else it could be done.
> 
> http://www.sacbee.com/content/news/story/5349258p-6338265c.html

Most likely. See Peter Wright's book _Spycatcher_ for how MI5 did it: 
very, very sensitive TRF receivers, if I recall correctly.

I expect that it's _loads_ easier on the freeway, with all those LOs
shrieking: just scan the spectrum for highest power, and change the
display content to suit. Judging by all the 10.7 MHz IF leakage I get
in my van, the average car radio is about as well RF-shielded as the
average Zip-Loc bag. It seems much easier in most ways than trying to
find the spy receiver with non-standard IF, though I suspect one might
have to use rather wide frequency buckets because any given receiver's
LO could be off a bit.

The only problem I see is deciding whether to scan for a low LO (RX
uses sum frequencies) or a high one (RX uses difference frequencies),
and it's easy enough to scan for both.

-- 
Mike Andrews
mikea at mikea.ath.cx
Tired old sysadmin