Let's also remember that, even if a villain intercepted your keystrokes, he'd have no way of knowing the context in which they're typed. He wouldn't know which strings of keystrokes represent passwords or which websites they apply to. He'd also have to know which computer it came from, given there might be dozens within his range.
Does anyone remember the TV detector vans that used to prowl the streets with the big aerials on top? And the claim made in their advert that they could even tell what channel you were watching?
YouTube - TV Detector Van Licensing Propaganda There are about two dozen of them on the road, and they do actually work! Well
some of them do up to a point....
In the days of analogue TV they would 'capture' the characteristic Intermediate Frequency signals off the set's tuner. More sensitive devices could pick up the stray re-radiation of video frequency signals.
I recall seeing one set of equipment demonstrated that could detect and re-construct the video frequency signal being used to drive the tube of a monitor (i.e. a set with no tuner). The point being to be able even to detect when recorded off-air broadcasts were being viewed on unlicensed premises such as offices and shops!
We were about to film it in fact. But unfortunately switching the camera on caused the whole thing to go absolutely mental! The report WAS eventually made though; Using a 16mm Bolex film camera ...A clockwork one (I kid you not!). The thing just couldn't deal with electrical noise....
And of course they're all useless beyone about 50 feet away anyway. The old joke back in the day was what do you call a man with a TV license in the Red Road Flats? ...Answer? A tourist!
The detector vans were
completely useless above about the 2nd floor. And as the number of sets increased and other devices that emitted RF interference became more and more common so the detector vans became less and less use!
Of course there's nothing more useful than a nice ready-salted packet of propaganda. and the myth of remote eves dropping is a very handy one to support for all sorts of reasons. And one of the favourite tools for maintaining that myth is this....
http://jya.com/emr.pdf And things like....
The Complete, Unofficial TEMPEST Information Page - Introduction From an engineering point of view it's certainly possible; But would be quite difficult to achieve. So difficult in fact that the equipment the U.S. Government are
rumoured to use for
this sort of purpose costs (supposedly) in the 'hundreds of thousands of dollars' range...
