[thecabal]

Thank you, that doesn't surprise me. I've always heard Tempest explained only in terms of CRT monitors, but I have a ham radio and I can tell you that my PCs splatter RF all over the spectrum. No wonder useful data can be extracted from it.

[Myrddin]

The front panel of my old Heathkit H-8 radiated so much trash that it could be heard on a 2-meter handheld with a rubber duck at 150 feet. I created primitive computer "music" using an AM radio to receive deliberately timed loops in 8080 assembler. A good spook shop can pick off Ethernet and keyboard controller emissions.

I made a service call on a tuna boat one day. The skipper complained of an awful buzz on his Collins HF receiver. My assistant was re-installing a VHF radio in the crow's nest. When I picked up the phone to call him, the "dial tone" buzz matched the buzz in the receiver. I traced the problem to a clipping diode across the dial tone generator. An .01 uF cap across the diode cleared the problem. Dumb luck on that one.