Sounds like the phone conversations i had with TV licensing at uni... No I don't have a License... No, I don't have a TV... No, I don't care if you don't believe me... No, you can't come in and check... [It was student flats and the office wouldn't/didn't let the TV Licensing mob in anyway...] No, you're not getting any money from me... No, I won't be getting a fine, because I don't require a license, because I don't have a TV... *loses temper* ...y'know what? If you are really so convinced i'm watching TV sans license... ****ing prove it. Oh, you can't/won;t... well kindly do one then.
The second people hear my accent they assume I'm just patronising and fine me anyway... I was told to "Stop putting on a silly accent" while paying my Council Tax the other week...IN SODDING KENSINGTON & CHELSEA.
That's discrimination, man. Get your compo-face on and go to whatever local rag will give you airtime.
EDIT: That said, go round kensington and/or chelsea looking like Compo and someone might mistake you for a certain MP.
Exactly. What is the difference between a live stream on youtube and a facetime chat with multiple people? do i need a tv license for that?
Just dont pay it. I have no idea why you did. If i keep sending you letters with scary words on it that are empty threats will you send me £150 too?
The fun thing about autocorrelation is that the absolute value means naff-all, you just looks at the change in value. With enough dynamic range in the sensor, only a tiny bit of light leakage would be just as effective as an open window.
The other fun thing? That's not actually what they do. D'you want to know what's really in the back of the TV Detector vans? Same thing that used to be in the back of 'em when they were "detecting the flyback transformer" on CRTs with an accuracy capable of telling you what room it was in: absolutely nothing. Nada. Zip. Zilch. They're mobile advertising billboards, designed to guilt you into paying up. Nothing more than that. Seriously. Empty. The way the TV Licensing Authority really detects unlicensed individuals is a lot simpler than clever camera systems somehow capable of correlating tiny amount of light leakages from uncalibrated TVs in an uncontrolled environment to the live output of the 400 possible channels it could be tuned to at any given time: they have a database of addresses from Royal Mail, and a database of people with a TV licence, they run the pair through uniq -u, and they send a letter to anyone whose address exists on "people in the UK" but not on "people who already pay us" threatening fines for being a naughty noodle. They used to force retailers to take your name and address when you bought a TV, too, but then figured blanket-bombing anyone who doesn't already have a TV licence under the assumption they're a filthy thief was quicker and easier.
99% are indeed just empty rented vans with some vinyl slapped on the side (usually done via a subcontractor). Actual detector vans do exist (and lack branding) and mainly continue in use so their existence in order to be driven out to any location where they actually want to put the time, money and effort into direct enforcement and where the normal knock-at-the-door-may-we-come-in routine has already failed. Van does its thing, signal detection used to create warranty to entry, warrant used to enter and gain direct evidence, and that used for prosecution.
@Gareth Halfacree, To be fair that's what they claim though, I'm not saying i believe them just that it's what they told a judge.
that's okay my Tv is only ever used as an external monitor when my gf's eye starts playing up (shes got a blood clot in her right eye). TV licencing did take us to court over it a few years ago I went told that it wasn't connected to anything other than a PC and explained about her eye offered to provide medical proof if they wanted and they dropped the case since then all we get every 12 months or so is 'do you need a licence letters' I ring them say no and they mark us off for another 12 months.
Request for a warrant from a Magistrate's court using an optical detector van as the reason for application. Here's a paper on a variant used for ATSC (the terrestrial digital TV standard used in the US). Here's an interesting one on detection using the audio channel: while you'd use a much higher frequency signal from an optical sensor (and have the choice of a composite signal or separating into R, G and B channels, or Y' U and V channels), the techniques they employ for correlation and classification are the same.
That's a good one, that is. That's not: unless I'm missing something (which is possible, 'cos I can't see more than the abstract without paying IEEE All The Monies), that's talking about detection of the actual broadcast signal - nothing to do with optical detection or detecting receiving equipment. That one's good again, tho'. Interesting stuff, thanks! I'm still suspicious as to whether the TVLA's alleged equipment A) exists (though claiming it does in court and it turning out not to would be a Silly Move, so let's assume TVLA ain't that daft) and 2) actually works better than sticking your finger in the air and going "yeah, he's watching broadcast TV."
Actually, there'd be one more 'gotcha' between "point a camera at a window" and "use the audio detector, but faster": Flatscreen TVs do not update line-by-line like old CRTs (which could literally just correlate the optical signal with the broadcast demodulated RF because that's all the TV is outputting), but neither do the vast majority perform 'global refresh' of the entire panel neatly all at one time. Instead, they update in segments in sequence, with a varying number being in different states of refresh at the same time. You'd need to add a windowing function to your sampler to combine everything within a sliding 1/50sec window in order to grab an entire frame in full (sliding needed because you do not know the signal phrase to start with), but as you're already doing a sliding autocorrelation because of the unknown delay between reception and display, that's not a huge burden. ::EDIT:: The ATSC one is in the RF domain, but for a similar desired effect (identify the direction an ATSC source is emanating from) using directional antennae rather than directional optical detection.
I still think the *biggest* problem here is that you'd be having to do this for the live output of, what, 85 channels if Freeview, 200 channels (minus radio) if Freesat, humpty-tumpty hundred if Virgin, and 600+ if Sky - so let's say 600 channels, given the crossover. Live. With as little delay as possible. In the back of a van. Are you sure about that? There's nothing in the abstract or keywords to suggest it's about direction finding; it appears to be about locking on to an ATSC signal that would otherwise be too weak for reception and decoding.
Yep, the detector is the easy bit, the signal reception and demodulating to compare against is the hard bit! There's nothing to stop you just recording the received signal then doing the correlation offline in non-real-time using recorded TV signals though, but given how compact modern DVB-T2 receivers are a single antenna, a distribution amplifier (probably the most expensive and least common part) and an array of DVB-T2 receivers would easily fit within the back of a small van. If it weren't for the distirbution amplifier, it could probably be man-portable! A 'basic' version could be made that simply switches through channels one at a time using a single receiver, and that could be handheld and battery powered without much issue. ::EDIT:: This would be a fun little project, albeit a completely worthless one to anyone who does not already have access to one anyway.
