----- Original Message ----- X-Loop: openpgp.net From: Steve Furlong <sfurlong@acmenet.net> Subject: Re: Burglar Politics, Tempesting PC's that watch TV and DVD regions
Lucky Green wrote:
Sunder wrote, quoting
It's my understanding that TV detector vans work by picking up the radiation emitted by cathode ray tube TVs - which should mean that, if you're rich enough to run an LCD monitor they'll never know you're a secret Paxman admirer.
A popular, but false, myth. The video cards radiate more than the CRT's. Laptops tend to be the worst offenders.
Cables are a problem, too. Video signals from a fully-shielded computer connected to a fully-shielded monitor by a regular, unshielded cable can be read. Effective snooping distance goes down, though I don't remember by what factor.
Which is a good reason to use a shielded cable, of the lowest practical length.. (check the resistance from one cable-end-housing to the other. If it's open it's NOT properly shielded. If it's shorted it MAY be properly shielded.) Further, whether or not the cable is shielded, putting one of those snap-on ferrite core filters at each end of the video cable, plus one each foot or so, does an excellent job preventing RF from propagating along the cable shield and radiating. Jim Bell, N7IJS.