"TV Detection" is actually just a civilian use of Radiation Intelligence, the kind of RF emanation that the USA has the entire TEMPEST hardening requirements https://en.wikipedia.org/wiki/Tempest_(codename) in order to prevent nation state attackers from being able to snoop data from their electronic equipment. This is a very real security principle and plenty of demonstrations out there to show how much information can be leaked from unshielded systems. You can check out gr-tempest which uses modern software defined radio hardware https://github.com/git-artes/gr-tempest. You can see pretty good demo of it here https://old.reddit.com/r/RTLSDR/comments/q59ofn/i_was_finall...
The basic truth is that over time it got harder and harder to build "simple" detectors to work out if people were using their TVs to watch the BBC (and this is the tricky part, a valid argument is "I don't watch the BBC", so they need to detect BBC channels being displayed on the TV and not detect other channels) and so it gradually became a less and less directly useful tool for the license enforcement teams to use, so it has sort of transformed from a genuine relatively accurate tool that doesn't need too much equipment, into a sort of mythical boogeyman that gets used to scare people into paying for the license, potentially backed up by cutting edge signals intelligence type equipment to occasionally prove it can be done and maintain the story. The wikipedia article is actually pretty good for explaining how the older detection mechanisms worked https://en.wikipedia.org/wiki/TV_detector_van#Detection_tech...
There was never an operational TV detector van (although there are dummy vans deployed). It was not an implementation of any RF technology. It was purely a PR campaign to improve compliance - obviously an effective one given your response.
I really can't agree with that view. While the modern versions are (and I did try to acknowledge this with my point about it being mostly a scare tactic now) extremely implausible. There exists ample evidence about how the old ones, particularly the first few generations, worked, all of which is rock solid electronic/radio technology theory stuff.
The wikipedia article I linked to references three separate old government documents over the span of nearly 20 years, each detailing subsequent method used for the first, second and third generation of TV detection equipment.
I'm not going to bat for the notion they have vans roaming the streets today with some sort of magically cutting edge NSA/CIA/GCHQ grade ELINT suite packed into a van that can sniff the digital signals leaking from the wiring from a flatscreen TV and run it through some sort of BBC only content ID while compensating for whatever distortions would obviously be introduced (and can be seen in the demo video in the reddit article I linked to) ... this notion is basically absurd, its clearly a scare tactic. No one is practically using the sort of technique documented by this 2013 research paper ( also linked from the wikipedia article, and showing with attached pictures that you can still theoretically do this sort of thing to a "modern" TV ) https://www.cl.cam.ac.uk/~mgk25/temc2013-tv.pdf to "detect" people watching The BBC on flatscreens TVs bought in the last 2 decades.
Whats not absurd, is that this clearly used to be pretty easy to do, like the circuitry for the first gen detector, could be built by any reasonably confident radio equipment person and definitely would work to detect the sort of TVs and TV broadcast technology used back in the early 50s. You can see it get more complex over time in each of the linked documents and obviously as it gets more complex it gets more expensive, and so you would probably see less of them built and operated... if they had a version that could actually do it in the 90's or early 00's then it probably cost them millions per van, so why would they ever risk that leaving the depot on off the chance it gets T-boned in an accident. This is classic mythos progression stuff, where the slightly extraordinary gets told and retold with each version seeming more implausible, turning ordinary events into mythic tales of heroes larger than life battling the gods... Except in this case its progressively more complicated and implausible sounding technology transforming into genuinely impossible for them to pay for it with their budget, transforming into a lie, into a myth, into a complete fabrication and conspiracy.
I agree that a myth has progressively grown, but maybe not the same one!
I’m not questioning the feasibility of the concept, but it is undeniable that no prosecution has ever arisen from evidence gathered by a TV detection van and the BBC refuses FOI requests for any details of investigations instigated by a detection. There were no detections.
The vans are and always have been a hollow deterrent.
Amusingly enough, I originally opened with a half paragraph about how the lack of prosecution shouldn’t be viewed as evidence of anything about the existence of the tv detector vans. But I cut it while drafting. Your completely right about the vans never being a source of evidence for a prosecution.
The complete lack of direct evidence tying a ban to a prosecution reminds me of the way the FBI are now treating Stingray cell site hijack tools… But it likely comes down to a combination of the enforcement agency’s limited powers and inherent ambiguities that couldn’t be eliminated from the technology. If they couldn’t prove that their signal couldn’t be coming from a TV in the neighbouring row house with perhaps a meter of separation and mirrored layouts placing rooms like master bedrooms and lounge rooms commonly back to back on the adjoining wall, and they lack the power to force someone to let them in, they effectively have their hands tied… but I can definitely see how it would be useful as a tool to quickly cull down lists of hundreds of potential unlicensed premises and to provide the sort of inadmissible hearsay that would provide internal evidence/justification for investigations using other means that could then actually be used for prosecution.
I suppose it was a hollow threat in the sense they could never just lock you up because some detector van snooped you out driving down the street. But in the sense that it was likely an efficient tool to help the agents doing the enforcement work over a large area, the side effect of selling it to the public was probably a bit of clever PR scam pulled by the enforcement agency, who needed all the help they could get since famously, you didn’t have to let them in which sort of cuts off a lot of ways for them to prove/investigate anything.
It was a hollow threat in that the vans deployed could not and did not make detections. There is no evidence that even a single operational van made a single detection. All known prosecutions and investigations were the result of human inspectors visiting residences without TV licenses. There’s no need for supposition or mental gymnastics about their secretive technological nature.
Thanks for catching that! Not living in the UK my familiarity is mostly with the topic as an example of civilian ELINT and the modern “anti-myth” that this stuff never worked/existed and it was a scam by the government since the 1950s. It’s past the edit window so I can’t fix that up in my comment unfortunately
The basic truth is that over time it got harder and harder to build "simple" detectors to work out if people were using their TVs to watch the BBC (and this is the tricky part, a valid argument is "I don't watch the BBC", so they need to detect BBC channels being displayed on the TV and not detect other channels) and so it gradually became a less and less directly useful tool for the license enforcement teams to use, so it has sort of transformed from a genuine relatively accurate tool that doesn't need too much equipment, into a sort of mythical boogeyman that gets used to scare people into paying for the license, potentially backed up by cutting edge signals intelligence type equipment to occasionally prove it can be done and maintain the story. The wikipedia article is actually pretty good for explaining how the older detection mechanisms worked https://en.wikipedia.org/wiki/TV_detector_van#Detection_tech...
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