As someone who has successfully carried out TEMPEST-style attacks against various kinds of devices and transmission lines for fun and profit, right up to reproducing the image from an LCD monitor in a different room, you have no clue what you’re talking about. For reasons that would take too long to explain here if you don’t already understand, it’s not going to let you read the ROM out of a microcontroller.
TV detector vans actually did
exist, at least in the UK, although I don’t know whether they were used in Germany. CRTs radiate a lot of electromagnetic energy, and older CRTs produced detectable amounts of X-ray radiation as well (the electron beam(s) striking the anode have high enough energy to produce X-rays, but newer CRTs use materials that provide better shielding). Big active matrix LCDs actually radiate even more energy than CRTs – the transparent conductive grid used to drive the pixels acts like a big radiating antenna, and there’s usually nothing in front of it providing significant attenuation. Surreptitiously recreating the image displayed on a monitor by detecting the electromagnetic emissions is generally referred to as Van Eck phreaking
, after Wim van Eck, who demonstrated it in the mid ’80s.
Radar detector detectors are real as well, and work by detecting electromagnetic emissions from the RF downconverters in the radar detectors. Newer radar detectors have far lower emissions, so they’re a lot harder to detect than the older ones were.