Andy Wade wrote:

I think you may be replying to the wrong post here...

John Rumm wrote:

But there is virtually no chance of detecting a TV that does not have
the aerial lead connected.


FSVO "no" such as "quite a high" :-). AIUI the detector vans have been
/ are being replaced by hand-held TV detectors, the operating principle
of which seems to be a closely guarded secret in the Beeb - but BBC R&D
at Kingswood had a hand in the development, so it could be something
quite advanced.

The linescan output, and that of the local oscilators in a typical TV
demodulating circuit are all easily detected with the right kit. Not
only that, but the nature of the signals makes them quite conspicous.


Line scan was used by the original detectors[1] in the 50s, replaced by
LO radiation in the later vans. If they've gone back to line scan
'radiation' (pedants read "induction field") it might make it quite
harder to find non-CRT displays, which are becoming very common.

I was not suggesting any particular technology is used, only
highlighting the fact that there are many ways to detect signal leakage
from largely unscreened boxes like TVs.

--
Cheers,

John.

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