From: Michael Motyka <mmotyka@lsil.com>
Date: Fri, 6 Nov 1998 02:03:17 +0800
To: ravage@EINSTEIN.ssz.com
Subject: Re: TEMPEST laptops (fwd)
Message-ID: <3641E026.918@lsil.com>
MIME-Version: 1.0
Content-Type: text/plain



Jim,

***
True, the point I'm trying to make to you folks is that it *ISN'T* the
absolute level of the signal that you are necessarily concerned with but
rather the dynamic range in that signal. Simply knowing there's a 3mV
signal
out there won't do you a damn bit of good unless you have enough signal
range
to decode the contents. In actuality you could be emitting GW's of
signal and
if there was only say 1uV of signal range you'd never get anything off
it.
***

The distinction you are trying to express is that not all signals have
equal information content and that it is the levels of the high-content
ones that matter. Fine, but shielding is indiscriminate so shield away.
And run your Tesla coil and some Ramones music to increase the ambient
noise while you're doing sensitive computing.

BTW - Aren't most receivers sensitive to RF field strengths in the 1
uV/m range? 
With cryogenically cooled front ends the nV/m range is probably usable.
Look for MIB carrying Dewars in your neighborhood! 
How cold do Peltier junctions get? 
Probably good enough for a sidewinder or a low-noise rcvr.

Mike

Gabba-gabba hey!