Author Topic: For the countries which need Radio and TV licenses. How TV Detector Vans work...  (Read 11201 times)

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Online Analog Kid

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OK, fine, you wrote about very carefully-shielded shortwave sets.
What about television receivers? Would it have been possible for an unmarked van parked outside someone's house to pick up the local oscillator frequency of their TV set?

(Forget parked outside an apartment bldg., with its jumble of mixed signals.)

To me, this falls in the same category as "yepper, them satellites can read your license plate from space!" misconceptions.
 

Offline BrianHGTopic starter

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Er, I don't think things ever worked that way; this is approaching tinfoil-hat territory. Would that even be possible (detecting someone's TV receiver IF frequency from far away)? I doubt it.

Oh really?  (DO this today...)

Get 1 FM radio and tune it to a blank station/static somewhere between 100mhz and 107mhz and keep listening.

Get a second old analog FM radio and manually tune its dial to ~10.7mhz below the the first radio and you will hear the static disappear as the first radio will now be tuned to the Local Oscillator of the second radio.

When I was a kid, I mangled an old clock radio with an audio jack tied through a cap to the supply voltage for the internal LO oscillation and made myself a pirate radio station which could be tuned in clearly for approximately 1 city block in both directions.

A TV van with a directional antenna can easily pick up any turned on radio and TV's LO within around a 2 to 4 house radius.  Since these vans use spectrum analyzers, they would see spikes for each channel come in and out as they would drive down a street.

In fact, during the second world war era, special radio tuners were developed which went through extravagant means to shield the LO from leaking out to prevent detection.   And you better believe that to do this, it was a nightmare.
« Last Edit: January 08, 2025, 01:31:54 am by BrianHG »
 

Offline Andy Chee

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In fact, during the second world war era, special radio tuners were developed which went through extravagant means to shield the LO from leaking out to prevent detection.   And you better believe that to do this, it was a nightmare.
I would imagine the LO emissions from vacuum tube equipment of that era, was far more easier to detect compared to today's low powered integrated semiconductor circuits.
 

Offline TimFox

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OK, fine, you wrote about very carefully-shielded shortwave sets.
What about television receivers? Would it have been possible for an unmarked van parked outside someone's house to pick up the local oscillator frequency of their TV set?

(Forget parked outside an apartment bldg., with its jumble of mixed signals.)

To me, this falls in the same category as "yepper, them satellites can read your license plate from space!" misconceptions.

Yes.
 

Online Analog Kid

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OK, a little online research reveals this. Admittedly not my preferred source (this is the Google "AI overview" in answer to my query), but it confirms what I believe to be true in this case, that at least in the era where it might have been possible for the surveyors to send out unmarked vans to snoop on unsuspecting viewers' LOs, that isn't at all what they actually did:

Quote
In the 1960s, Nielsen primarily conducted TV surveys using "viewer diaries," where selected households would manually record what they watched on television by filling out a paper log, providing demographic information about the viewers, which was then compiled and analyzed to generate audience ratings; this method was later supplemented with the introduction of "audimeters," small devices attached to televisions that automatically recorded viewing data and transmitted it to Nielsen via phone lines, providing more detailed minute-by-minute viewing information.

So while it might have been possible to do this electronically, it's quite doubtful that's how it was done. And it jibes with what I'd heard about the process of gathering TV audience surveys.
 

Offline BrianHGTopic starter

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In fact, during the second world war era, special radio tuners were developed which went through extravagant means to shield the LO from leaking out to prevent detection.   And you better believe that to do this, it was a nightmare.
I would imagine the LO emissions from vacuum tube equipment of that era, was far more easier to detect compared to today's low powered integrated semiconductor circuits.
Yes, older tube equipment and older simple transistor based radio tuners, especially those with good receivers did radiate quite a bit.  Especially old TV tuners as they usually outperformed the smaller tuners in VRCs and cable boxes.

As for scanning neighborhoods to determine viewership ratings in the USA, I do not think this ever happened country wide.  Perhaps as an experimental test in one city, but, it would take too long and there would be too many cross signals to isolate making the test a flop.
 
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Online coppercone2

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I don't know, I think in any normally populated area there would be so much crap that it would not be possible unless there was some guy on your roof next to the antenna

plugging a antenna into a 'power signal' in the power supply through a coupling capacitor is I think a bit more powerful then the natural emissions? are you sure thats a good comparison?

not to mention faulty equipment and crazy wiring making the signals go everywhere? Especially if its tuned to regions that are not empty.

Now, if a spy has a radio tuned in some RF 'dead zone' waiting for a signal, in some isolated place, that might be somewhat easier to pick up (waiting for numbers station broadcast), but if your listening in the normal 'fm band', in a normal populated area, with a normally hook up radio, I think it might be a bit of security theater going on.


and I think if it was that easy, it would be exploited and known, i.e. burglars known to listen to RF signals to wait till someone falls asleep before doing some 'cat work'. Especially when you had battery powered radios, you basically know nobody would leave that on after they went to sleep, because its expensive, and also annoying to replace batteries


I would fully expect that getting a job as a " RADIO DETECTOR VAN DRIVER" would be a appealing position for any half decent criminal. Lights out, radios dead, whats that give you like a 50% lower chance of having a close encounter with a occupant during a burglary? You can even get rid of that nagging urge to revisit the crime scene to issue a citation later. And they basically let you case the place at night, regularly, with zero suspicion, so you can learn the exact habits of targets. I think this would give you real life  'criminal superpowers' And you can probably weasel your way out of a arrest or lessen charges because you can say you got job frustration about 'in determinant signals' or some other crap that possessed you to enter someones property.


I suspect in practice this radio van did not work very well.
« Last Edit: January 08, 2025, 04:51:45 am by coppercone2 »
 

Online PlainName

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Quote
So while it might have been possible to do this electronically, it's quite doubtful that's how it was done. And it jibes with what I'd heard about the process of gathering TV audience surveys.

No idea what goes on over the pond, but here in the UK there was a strong rumour that the TV detector vans didn't actually detect anything and just went out for show. When they visited some area, the number of licenses being taken out increased...

I am sure they did do detection (and that some were just for show), but they didn't have a readout "No. 6 is illegal" and it came down to the skill of the operator, who didn't always get it right. And it's cheaper to drive an empty van around than to equip it with the stuff and pay skill wages, etc.

As to the relevant means of taxing, some countries did this out of general taxation and I think that was the wrong approach for public broadcasting. In the UK it's a license, and you only need to pay if you're watching the TV, so if you have some ideological reason against either paying or watching the solution is easy. And since the government isn't involved and doesn't get the dosh, the output isn't politically skewable (easily). Of course, the downside of licensing broadcast receivers is that it's relatively easy to freeload, whereas with paying from general taxation it isn't.
 

Online JPortici

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Why it has to be my problem what some TV station is required to do? If the Gov requires it, the Gov should pay for it.

Edit: and by the way, Public libraries are free, at least here.

And how do you think the government pays for any of these things?

with ~43% of my income?
I also pay for my internet connection (with VAT of course) so i don't think i need to pay a license because i own a screen with a TV receiver (not connected, of course. My home came with an antenna, amplifier and cables, i'll be more than happy to strip them away if i have to prove i can't get TV)
 

Offline tom66

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TV detector vans don't work in the UK (and I doubt they ever did).  They are purely a marketing ploy by Capita (the contractor) and the BBC.

There's a very simple way that the TV Licencing people know to write to you, because every time you buy a new TV the retailer is required to notify your address to the authority. 

But, owning a TV in and of itself doesn't require a licence; we do not consume BBC content any more and have gone licence free for some time. 

I think the BBC will need to reform how the licence fee is collected as currently any terrestrial consumer of content pays a licence fee (even if they do not watch BBC services) but no consumer of streaming content does; fundamentally what is the difference here? 
 
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Offline themadhippy

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because every time you buy a new TV the retailer is required to notify your address to the authority. 
no longer the case,it was scrapped around  2013
 
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Offline tom66

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Quote
because every time you buy a new TV the retailer is required to notify your address to the authority. 
no longer the case,it was scrapped around  2013

That probably explains why I got letters at my address despite only having a second hand TV.   They just seem to paper-bomb any house with an address.  I did fill out a "don't need a licence" form at one point but they kept sending letters so I don't bother any more, let 'em waste their postage.
« Last Edit: January 08, 2025, 12:36:14 pm by tom66 »
 

Offline themadhippy

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They just seem to paper-bomb any house without an address
how can you get post without an address  >:D

But yea it seems they just target every address  thats dosnt have a license.Heard crapias more recent misinformation  tactics is saying you need a license if your watching a  live stream online ,conveniently missing out  tv from the sentence.
« Last Edit: January 08, 2025, 12:38:03 pm by themadhippy »
 

Offline tom66

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Typo, corrected.
 

Online PlainName

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But, owning a TV in and of itself doesn't require a licence; we do not consume BBC content any more and have gone licence free for some time. 

I don't think you really know what the license covers. From the TV Licensing website:

Quote
Home or away, you could still need a TV Licence to cover you. Whether you’re watching on a TV or a different device.

For instance, if you're catching up on BBC iPlayer on your phone as you commute to work, you need a licence. Streaming a live YouTube channel via your game console? You need a licence. Getting stuck into Sky Sports action live on your laptop or tablet? You need a licence for this, too.

This includes recording and downloading.

TL;DR: You need it for reception of live broadcasting, not just BBC output.
 

Offline tom66

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I'm well aware of what the TV Licence covers, thank you very much.

We do not have an antenna connected to the TV, and whilst the TV is capable of accessing BBC iPlayer, that function is not used.

Only external HDMI devices and the integrated streaming functions are used - all of which do not require a licence fee to be paid.

There is some debate over what the "live streaming" statement covers; but it's generally accepted that unless the stream is also accessible terrestrially as it is broadcast, it is not covered by the licence fee.
 

Offline nctnico

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I always found the concept of TV licensing bizarre. It is like you pay for your own brainwashing.
Agreed. Especially with all the commercials you got anyway. TV licensing used to be around in the Netherlands as well but it got turned into a tax. But since the dawn of ADSL internet I have been downloading what I want to watch and have not watched TV ever since. Its OK to pay for the content through commercials as part of buying a product for as long as I don't have to consume the commercials. To add to the insult, the programs on public (government funded) channels I pay for with tax money are behind a paywall so I can't see those.  :palm: IMHO Netflix is a much better concept.
« Last Edit: January 08, 2025, 02:02:55 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Monkeh

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Why it has to be my problem what some TV station is required to do? If the Gov requires it, the Gov should pay for it.

Edit: and by the way, Public libraries are free, at least here.

And how do you think the government pays for any of these things?

with ~43% of my income?
I also pay for my internet connection (with VAT of course) so i don't think i need to pay a license because i own a screen with a TV receiver (not connected, of course. My home came with an antenna, amplifier and cables, i'll be more than happy to strip them away if i have to prove i can't get TV)

It's interesting how upset people get over the option not to pay for a service they don't use..
 

Offline m k

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Back in the day Nielsen households were top secret, maybe they still are.
Each of them represented quite a chunk of viewers.

There were also rumors that some were bribed by broadcasters.
Maybe some bad stuff had too good ratings.
Advance-Aneng-Appa-AVO-Beckman-Danbridge-Data Tech-Fluke-General Radio-H. W. Sullivan-Heathkit-HP-Kaise-Kyoritsu-Leeds & Northrup-Mastech-OR-X-REO-Simpson-Sinclair-Tektronix-Tokyo Rikosha-Topward-Triplett-Tritron-YFE
(plus lesser brands from the work shop of the world)
 

Offline tom66

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I think it's important to have some form of public broadcaster, for news and current affairs documentaries and such.  That can be funded by a tax on, for instance, all streaming subscriptions.

I am not sure it is appropriate to ask people to pay for Doctor Who (an entertainment show) if they want to watch, say, Sky Sports, when they had nothing to do with each other.  Since Sky supplies its own infrastructure there is no cost to the BBC or the government for Sky's operations.   Doctor Who is the kind of content that belongs on a streaming platform, where people can pay for it if they want to access it.
 

Offline Monkeh

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I am not sure it is appropriate to ask people to pay for Doctor Who (an entertainment show) if they want to watch, say, Sky Sports

But bear in mind that the funding isn't quite so clear cut. Yes, they receive the majority of their funding from the licence fee, but they also make something to the tune of £1b from commercial activities - like selling the broadcast rights to Doctor Who.
 

Offline DavidAlfa

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That worked for very old tvs (Unshielded wooden box full of radiating wires), I doubt they can sense and LO or IF frequencies in modern tvs.
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Offline Ranayna

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I wonder what happened when home computers became a thing, but you never tuned into any over the air TV broadcasts...

Were people nailed for that?
In my case, yes.
That must be now more than 35 years ago, I, as a small child, maybe 6 or 7, opened the door to a pair of license checkers. They asked me if i had a TV in my room, which i, having been taught not to lie, answered yes.
That it was not used to watch TV, but was only connected to my Commodore 128 did not matter.
In the end that truthful answer did cost around 600 Deutsche Mark.

The german TV licensing scheme required a license for each and every receiving device, wether TV or Radio.
I distinctly remember the big, fat warning in my Kosmos Electronics kit. That included an AM detector Radio, with a big warning that it is illegal to use without a license :D
 

Offline coppice

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I think it's important to have some form of public broadcaster, for news and current affairs documentaries and such.  That can be funded by a tax on, for instance, all streaming subscriptions.

I am not sure it is appropriate to ask people to pay for Doctor Who (an entertainment show) if they want to watch, say, Sky Sports, when they had nothing to do with each other.  Since Sky supplies its own infrastructure there is no cost to the BBC or the government for Sky's operations.   Doctor Who is the kind of content that belongs on a streaming platform, where people can pay for it if they want to access it.
Its not just paying for Doctor Who when you watch Sky. If you are a foreigner spending time in the UK, you never watch any UK broadcast TV, or use equivalent internet services like iPlayer, and merely stream the TV from your homeland over the internet, you need a UK TV licence.
 

Offline coppice

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I am not sure it is appropriate to ask people to pay for Doctor Who (an entertainment show) if they want to watch, say, Sky Sports

But bear in mind that the funding isn't quite so clear cut. Yes, they receive the majority of their funding from the licence fee, but they also make something to the tune of £1b from commercial activities - like selling the broadcast rights to Doctor Who.
I don't know if this has changed, but people who studied the economics of TV services used to complain about the BBC a lot for overpaying to get the broadcast rights to foreign TV shows (mostly American), while offering its own catalogue of highly desirable shows for the world market, like its rich natural history catalogue, at bargain basement prices.
 


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