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tv detector vans |
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#1 |
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Forum Member
Join Date: Sep 2011
Posts: 5,341
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tv detector vans
can someone clear this up once and for all.could they really track tvs or were they just a bluff to get people to buy tv licenses when they saw a van in their area
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#2 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
can someone clear this up once and for all.could they really track tvs or were they just a bluff to get people to buy tv licenses when they saw a van in their area
Back in the mid 70's I was taken inside one, and shown how it all worked - basically a lot of expensive professional radio and electronics gear, and two VERY highly skilled and qualified engineers to use it. They were able to pick out individual TV's in the workshop, and tell me which channels they were on - and they were completely right on every one. But as far as I'm aware there haven't been any for a number of decades now - far too expensive, and not cost effective. Much cheaper to send guys round knocking on doors. |
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#3 |
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Inactive Member
Join Date: Apr 2012
Posts: 2,021
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All valves radiate radio frequency signals. So when an old fashioned TV was busy processing the TV signal it would be re-radiating it's own signal. If I was doing it I would try to detect the output of the TV's largest valve, the CRT.
It's quite a simple process to scan the spectrum and detect a signal then to use directional aerials to get a bearing. Of course you'd need at east three bearings to triangulate a position and even then it might not be too accurate. It is claimed in various places on the internet that no detector van evidence was ever used in a UK court. But that's typical of the BBC, scaring people. |
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#4 |
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Join Date: May 2013
Location: Getting me coat
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Quote:
It is claimed in various places on the internet that no detector van evidence was ever used in a UK court.
Looks like it was discussed here at the time: http://forums.digitalspy.co.uk/showthread.php?t=1480075 |
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#5 |
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Join Date: May 2008
Location: Lancashire
Posts: 8,267
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Yes they could - but even back when they existed there were only ever a very small number of real ones, most were just dummy vans which scared people in to buying a licence.
Back in the mid 70's I was taken inside one, and shown how it all worked - basically a lot of expensive professional radio and electronics gear, and two VERY highly skilled and qualified engineers to use it. They were able to pick out individual TV's in the workshop, and tell me which channels they were on - and they were completely right on every one. But as far as I'm aware there haven't been any for a number of decades now - far too expensive, and not cost effective. Much cheaper to send guys round knocking on doors. |
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#6 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
Worked for BT and whilst I cannot remember the year(s) TV Detector Vans used to be parked overnight at the local exchange, very strange cone shaped aerial on the roof, and yes the engineer that went out with this vehicle was a very highly skilled engineer.
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#7 |
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Join Date: May 2005
Posts: 30,036
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Quote:
can someone clear this up once and for all.could they really track tvs or were they just a bluff to get people to buy tv licenses when they saw a van in their area
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#8 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
All valves radiate radio frequency signals. So when an old fashioned TV was busy processing the TV signal it would be re-radiating it's own signal. If I was doing it I would try to detect the output of the TV's largest valve, the CRT.
![]() Valves don't radiate particularly, and transistor sets were just as easily detected as valve ones. Specific signals looked for were the tuner LO emissions (which told them which channel you were on), and the colour sub-carrier oscillator emissions (at 4.43361875 MHz) which proved that it was a colour set. |
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#9 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
There's no such thing as detector vans.
![]() ![]() As far as I'm aware the last ones were old Commer vans?. |
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#10 |
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Join Date: May 2005
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Quote:
As I've always said - not THESE days
![]() As far as I'm aware the last ones were old Commer vans?.
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#11 |
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Join Date: Sep 2004
Posts: 14,718
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Quote:
But that's typical of the BBC, scaring people.
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#12 |
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Join Date: Oct 2007
Posts: 5,008
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Quote:
Worked for BT and whilst I cannot remember the year(s) TV Detector Vans used to be parked overnight at the local exchange, very strange cone shaped aerial on the roof, and yes the engineer that went out with this vehicle was a very highly skilled engineer.
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#13 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
The one I saw had 2 Wolesey colour king aerials on the roof mounted back to back so they were beaming in opposite directions. It was at the BBC TV Centre doing a test of some sort driving round and round the inner circle with a battery operated TV in the middle of the circle.
![]() More likely a test van of some purpose - perhaps used for doing coverage tests on new transmitters?. |
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#14 |
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Join Date: Oct 2007
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Quote:
That sounds nothing like a detector van
![]() More likely a test van of some purpose - perhaps used for doing coverage tests on new transmitters?. |
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#15 |
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Join Date: Jun 2011
Posts: 2,735
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detector vans do not exist
they have vans pretending to do detecting they have a database of people who have licences and check on people who dont i have no tv goodbye closes door exits thread |
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#16 |
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Forum Member
Join Date: Oct 2007
Posts: 5,008
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Quote:
detector vans do not exist
they have vans pretending to do detecting they have a database of people who have licences and check on people who dont i have no tv goodbye closes door exits thread |
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#17 |
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Join Date: Jun 2011
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Quote:
There may not be any now, but they certainly used to exist, and they were not pretending.
can you show us bbc accounts where they detail research cost and training costs for detecting equipment/staff training etc if anyone has been prosecuted , what evidence did the tv licencors produce in court aside from no tv licence and owns tv? answer all these i might believe they exist but since you wont be able to , they dont exist also tvs/monitors are so shielded you prob couldn't detect them while in same room, never mind outside on street |
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#18 |
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Join Date: Jun 2011
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wrong thread lol
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#19 |
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Join Date: Apr 2006
Location: North Derbyshire
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Quote:
It had the words "TV Detector Van" or similar on the side.
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#20 |
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Forum Member
Join Date: Apr 2006
Location: North Derbyshire
Posts: 41,789
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Quote:
could you explain the tech used to detect your tv?
Quote:
can you show us bbc accounts where they detail research cost and training costs for detecting equipment/staff training etc Quote:
if anyone has been prosecuted , what evidence did the tv licencors produce in court aside from no tv licence and owns tv? Quote:
answer all these i might believe they exist but since you wont be able to , they dont exist Quote:
also tvs/monitors are so shielded you prob couldn't detect them while in same room, never mind outside on street As I've said before, detector vans DID exist, but I don't believe they have done so for a considerable number of years. They were never cost effective, and simply knocking on doors is far more efficient (bearing in mind the detector van operators had to knock on the door anyway, if they detected a TV inside). |
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#21 |
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Join Date: Jul 2003
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Quote:
also tvs/monitors are so shielded you prob couldn't detect them while in same room, never mind outside on street With the TV turned off everything is fine, with it turned on then you'll need to angle it just right to hear anything but interference.
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#22 |
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Join Date: May 2004
Location: southern Ireland
Posts: 126
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Here's a picture of a TV detector van in Ireland, outside RTE, picture probably dates from the 1960s:
http://www.2rn.ie//vintage-gallery/p...office-014.jpg pt = Posts and Telegraphs |
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#23 |
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Join Date: Jul 2008
Location: West Yorks
Posts: 6,180
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Quote:
could you explain the tech used to detect your tv?
can you show us bbc accounts where they detail research cost and training costs for detecting equipment/staff training etc if anyone has been prosecuted , what evidence did the tv licencors produce in court aside from no tv licence and owns tv? answer all these i might believe they exist but since you wont be able to , they dont exist also tvs/monitors are so shielded you prob couldn't detect them while in same room, never mind outside on street |
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#24 |
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Inactive Member
Join Date: Apr 2012
Posts: 2,021
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Quote:
Sorry, but there's no accuracy anywhere in those sentences
![]() Valves don't radiate particularly, and transistor sets were just as easily detected as valve ones. Specific signals looked for were the tuner LO emissions (which told them which channel you were on), and the colour sub-carrier oscillator emissions (at 4.43361875 MHz) which proved that it was a colour set. I know because I did it many years ago whilst working for a sophisticated electronics organisation based in Cheltenham. |
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#25 |
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Forum Member
Join Date: Apr 2006
Location: North Derbyshire
Posts: 41,789
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Quote:
It's possible to receive a radio signal from Australia on a 1/2 watt transmitter so detecting the radiation from a valve such as a hot CRT from 30 yards is a piece of cake.
I know because I did it many years ago whilst working for a sophisticated electronics organisation based in Cheltenham. |
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