The dish on TEMPEST

[Lucky Green <shamrock@netcom.com>]

The following is from a tread involving a friend of mine. An ex-military 
fellow. Take it for what you want. I believe him.



>>>     This depends in large part on the strength of the
>> >     degausser and how long it remains powered up.  The one
>> >     I have I used to "clean" 10.5 inch tape reels written
>> >     at FM broadcast quality to a noise level -20db down from
>> >     brand new tape - this back in my quadraphonic stereo
>> >     days.  It will not quite suck satellites out of orbit...
>> >     TWA planes, maybe.
>> 
>> 
>> -20dB down from new would be a better spec if new tape was typically 
>> nulled rather than just blank low-level white noise.
>> 
>> However, even so, a SQUID is a very scary thing....


    I've been out of commission for a week and found 276
    messages in my in-box today.

    The tapes I was writing about were those already
    "prepared" for recording "items of interest", and
    had already been degaussed in the preparation
    procedure to FM broadcast standards then/there.
    My little hummer would take whatever whit noise
    remained even then to a further 20 dBA DOWN from 
    the ridiculous levels then/there specified.

    In other words, it's pretty good.  Of course,
    IF Big Brother wants, there are any number of ways
    for him to obtain whatever information he wishes.

    I recall long, long ago, I was privileged to watch
    a demo of equipment (1955 or 1956, I forget exactly)
    in a truck parked a MILE away from our CommCenter,
    in the years before Faraday cages, TEMPEST, etc., 
    and watch these guys print out a 5x5 copy of our
    top secret traffic as it was read by the [elided upon request]
    one-time-tape encryption devices.

    Shortly after that demo, our CommCenter was moved 
    into a cave (no joke) and modified to "low level"
    dc signalling voltages.  And other measures were taken to 
    screen the area...

    I _have_ led an interesting life...


    As for Squids, only if you read Jules Verne are
    they scary. Otherwise, cleaned and fried with 
    a tangy dipping sauce,  well, that's another story!

--Lucky