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[UK] Television detector

F

Frederick Williams

Jan 1, 1970
0
I haven't heard much about television detector vans lately but we used
to be told that they could detect a television even if it was switched
off and they could even tell which room it was in.

How do such detectors work?

[I know nothing about electronics but my guess is that televisions
contain circuits that resonate at characteristic frequencies*. When
those circuits have electro magnetic radiation of those frequencies
directed at them, they resonate and re-emit those frequencies and such
emissions can be detected. Something like that.

* I'm using the phrase "characteristic frequencies" loosely.]
 
J

John Tserkezis

Jan 1, 1970
0
Frederick said:
I haven't heard much about television detector vans lately but we used
to be told that they could detect a television even if it was switched
off and they could even tell which room it was in.

How do such detectors work?
[I know nothing about electronics but my guess is that televisions
contain circuits that resonate at characteristic frequencies*. When
those circuits have electro magnetic radiation of those frequencies
directed at them, they resonate and re-emit those frequencies and such
emissions can be detected. Something like that.
* I'm using the phrase "characteristic frequencies" loosely.]

They don't apply so much anymore, mainly because of technological changes.

CRT displays, have a number of deflection coils that direct the
electron beams to where it's supposed to go. The coils that do this were
driven by the analogue video stream, and the signal is easily
discernible by relevant radio receivers and directional antennas.

LCD displays don't use such driving technology, so can't be sensed with
any real accuracy. Same goes for PC tuner cards that translated the TV
display to a different resolution even though you may have a CRT monitor
attached to the computer.

However, doing that (TV vans) proved expensive.

The more reliable method, was to look up the database of who's already
paid up, assume that *everyone* has a TV, and just doorknock asking why
they haven't paid up yet.

The usual suggested course of action is to avoid them (so they need to
come back at a later time, hopefully getting tired of the exercise), or
leave them at the front door (there is no legal requirement to bring
them in) and simply state you do not watch the BBC (which are the only
channels legislated by these fees).

Of course, if you don't have a TV, you could invite them in and show
them (they'll take note and not bother you again).
Or if feasible, hide the TV, but might prove difficult if you have a
240" monster hanging off the wall. PC attached tuner cards are more
difficult to prove, they're not immediately visible, and the guys in
suits are not rocket scientists, and if it doesn't look like a TV it
probably ain't a TV.

If you really *don't* watch the BBC, good luck to you, you're going to
have a fun time trying to prove it.
 
J

Jasen Betts

Jan 1, 1970
0
I haven't heard much about television detector vans lately but we used
to be told that they could detect a television even if it was switched
off and they could even tell which room it was in.

How do such detectors work?

dunno. it's pretty hard to detect a TV that's turned off.
[I know nothing about electronics but my guess is that televisions
contain circuits that resonate at characteristic frequencies*.

Old style CRT tvs emit emit electromagnetic waves magnetic waves from
that magnets that control the vertical and horizontal scanning of the
electron beam.

To detect LCD tvs they probably use a directonal microhone and listen
for the audio track of the TV shows.


--- news://freenews.netfront.net/ - complaints: [email protected] ---
 
P

Phil Allison

Jan 1, 1970
0
"Frederick Williams"
I haven't heard much about television detector vans lately but we used
to be told that they could detect a television even if it was switched
off and they could even tell which room it was in.

How do such detectors work?


** Only details I ever read involved picking up spurious local oscillator
( ie VHF ) radiation from the TV set emitted via the owner's antenna using a
directional loop on top of a van.

Don't think it has been done much since the 1960s.



..... Phil
 
F

Frederick Williams

Jan 1, 1970
0
John said:
If you really *don't* watch the BBC, good luck to you, you're going to
have a fun time trying to prove it.

This hints at some misunderstandings.
 
B

Baron

Jan 1, 1970
0
John Tserkezis Inscribed thus:
If you really *don't* watch the BBC, good luck to you, you're going
to have a fun time trying to prove it.

Actually, a few years ago a local radio ham got prosecuted for not
having a TV license. He ended up in court and proved his case. I
don't remember the details but it ended up in the local papers and
eventually made national news. I do recall that the whole episode made
the TV enforcement people look quite silly.
 
J

John Tserkezis

Jan 1, 1970
0
This hints at some misunderstandings.

Does it?

Here in Australia, I never watch the ABC. (Similar to the UK BBC, it's
public funded, except we pay for it via taxes, not separate fees like in
the UK).

Truth be said, I *can't* watch it due to circumstances of positioning
and terrible antennas. That said, I watch very little commercial TV
either for that matter.

Anyway, we also had separate fee payments like the UK before some
politician before my time thought it would be a good idea to bundle it
up and do away with visible fees.
Quite sensible actually, amazing that a politician had come up with the
idea...

I don't have the patience to explain myself to them like that. I'd be
more likely to tell them to get f%#ked if they came round every so often.
Much like the Mormons and the Jehovas. I don't pay attention to
*their* particular brand of program material either.

Except the tax collectors don't ever go away...
 
This isn't true; watching ***any*** TV broadcast requires a TV licence
in the UK. Incidentally, one genuine exemption, foreign-language
satellite programming uplinked outside the UK was abolished in 2004.

If the program was abolished six years ago, I guess it makes sense that no
license would be required to receive it now.
 
J

John Tserkezis

Jan 1, 1970
0
This isn't true; watching ***any*** TV broadcast requires a TV licence
in the UK. Incidentally, one genuine exemption, foreign-language
satellite programming uplinked outside the UK was abolished in 2004.

Whoops, I stand corrected. I was under the impression it was similar
to the Australian ABC issue, where the fees only paid for the ABC.

Commercial channels were on their own as far as revenue raising was
concerned.
 
No "program" was abolished, an exemption was. (Is English not your
first language?)

Yes, in fact it is. It's obviously not be yours, however. Hint: the
independent clause doesn't modify the subordinate clause. In this case
"abolished" doesn't modify "exemption", rather "programming".
Until 2004, UK residents were exempt from the need
for a licence provided they only watched channels, from a non-EU
country, via satellite, provided that the channels was uplinked to the
satellite from outside the UK.

Then why didn't you say that (and I thought I used too many commas).
 
F

Frederick Williams

Jan 1, 1970
0
Frederick said:
I'm going away for a few weeks, but I'll try to remember to reply when I
get back.

It may be that I have misunderstood you, in which case I apologize, but
just in case it's you who have misunderstood me I'll make these points:

(i) In the UK one requires a licence to receive any TV broadcast, not
just those of the BBC.

(ii) I don't need to prove anything. If TV Licensing feels it needs to
prove something let it try, the matter is of no interest to me.

(iii) I asked about detecting the presence of a switched-off TV because
it's just that which I was interested in.
 
J

John Tserkezis

Jan 1, 1970
0
Frederick said:
It may be that I have misunderstood you, in which case I apologize, but
just in case it's you who have misunderstood me I'll make these points:
(i) In the UK one requires a licence to receive any TV broadcast, not
just those of the BBC.

Ah, I stand corrected. I've just checked (which oddly enough is what I
should have done in the first place) and yes, there are two licence
fees, one for colour, one for black and white.

There are exceptions, such as if you're over 75, or if you're blind. I
don't get the bit that old foegies get TV for free, but if you're blind,
you still have to pay. Half price, but still have to pay.

What's REALLY odd, if you're blind there are still TWO licensing
models, one for colour and one black and white.

Ah, money gouging with bureaucracy at it's best.
(iii) I asked about detecting the presence of a switched-off TV because
it's just that which I was interested in.

I'm pretty sure at least a couple had replied no, turned off TVs cannot
be detected.
 
F

Frederick Williams

Jan 1, 1970
0
John said:
Frederick Williams wrote:

I'm pretty sure at least a couple had replied no, turned off TVs cannot
be detected.

Do you mean we were lied to? Shankly I'm frocked?
 
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