From: Lyal Collins <lyalc@ozemail.com.au>
Date: Wed, 29 May 1996 19:54:22 +0800
To: Julian Assange <proff@suburbia.net>
Subject: Re: Tempest Info
In-Reply-To: <199605282356.JAA29834@suburbia.net>
Message-ID: <31AD02EB.5BF5@ozemail.com.au>
MIME-Version: 1.0
Content-Type: text/plain


Julian Assange wrote:
> 
> >
> > Bill Stewart writes:
> > >  Also, of course, your electrical power system needs to be
> > >  shielded and filtered, so only 60Hz gets through, unless you
> > >  plan to stick to laptops and bring in spare battery packs.
> >
> > At HoHoCon a few years ago, someone did a tempest demo and mentioned that
> > signals could be recovered from water pipes!  Fire sprinkler systems were
> > specifically mentioned...
> 
> Water pipes are often form the earth line. If only 60hz (US) can get through
> the power cables then only 60 hz can get into the water pipes (I'll ignore
> re-radiating, because water pipes are the least of your problems there).

As the water pipe can form a signal "drain", monitoring that with respoect to an 
artificial refernce "earth" allowsthe signal(s) to be reccovered, unless the waterpipe is of very low 
impedance.
lyal

-- 
All mistakes in this message belong to me - you should not use them!