Certainly the science of detecting a TV is possible, in fact tracing local oscillator radiation from a Superhet receiver on known frequencies was a proven method of spy detection.
Even for a modern TV with say digital freeview, or sky/cable?
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Television Licensing Authority enforcement officers
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Posted 1 year ago #
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Digital TV is, and always will be, transmitted in analogue.
The principles used in decoding the incoming signal are always the same.
Posted 1 year ago # -
Even Sky and cable? Sky is much higher frequency tho is it not? Will that not travel as far?
Posted 1 year ago # -
Yep.
With analogue TV you use a simple analogue decoder to recover an analogue signal. In the old days the signal was then amplified and fed straight into the CRT display.
With digital TV you use a much more sophisticated analogue decoder to recover a digital signal.
Whether its sat, terrestrial or cable, the incoming signal is converted into a common (analogue) frequency (used to be around 39Mhz) It was that frequency that the detector vans used for monitoring. Actually not strictly true, but I dont want to go into Local Oscillator principles here
Savvy license dodgers could change that frequency, but it needed sophisticated test gear to do properly.
Posted 1 year ago # -
Yes I understand how receiving the TV works. What I don't understand is the secondary radiation to which Z11 refers.
Posted 1 year ago # -
We had a visit from the Licence inspector man once. We hadn't had a licence for almost a year because the person in our student house who we'd given the licence money to (we later found out) had spent it on beer instead and had obviously hidden every TV licence letter that must have arrived.
The inspector could see the TV from the front door and wrote on his form "TV on and watching BBC1"
All he said was "best get a licence lads". We got a licence the next day and we never heard from them again.
Posted 1 year ago # -
Yes I understand how receiving the TV works. What I don't understand is the secondary radiation to which Z11 refers
The spy stories I'd heard where related to reading screens remotely, and this depended on an electron gun scanning the screen.. so LCD/plasma wouldn't work.
Don't know if modern TV's even use a superhet or replace it in software now?Posted 1 year ago # -
I have simply wrapped my house in bacofoil
Posted 1 year ago # -
When they come round, just cover yourself in chicken blood, and answer the door wearing only a balaclava and a pair of wellington boots.
They won't come back again....
Posted 1 year ago # -
Don't know if modern TV's even use a superhet or replace it in software now?
Signal is too fast and low level to do in software.
One day perhaps.
Posted 1 year ago # -
When they come round, just cover yourself in chicken blood, and answer the door wearing only a balaclava and a pair of wellington boots.
Ahh, that'll be why it didn't work. I used goats blood
Posted 1 year ago # -
Schoolboy error.
Posted 1 year ago #
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