Faraday cages

beamendsltd wrote:

> How that should be dealt with is a political matter,
> not technological.

.... and we all know the answer to that - ignore the possibility and
fleece the motorist yet again.

> My vehicle tracking system sounded a dangerous driving alert the other
> day. I was doing 144 mph in our office car park. Even better, I was
> sat at my desk with the keys in my pocket....

> The GPS had gone wobbly and jumped me across Barnsley and back in 18
> seconds.
Tim Hobbs

..Snipped a bit....Tim, Sorry had to laugh at this one. SSOH
Now that's interesting, a keyless car that scorches your arse, then
gives you one, then trys to get home denying it all ever happened
18 seconds for a jump is nearly as quick as me, and while it was wobbly
as well. Did it hurt? d;-))))) LOVL Dave

--
Amateur Radio Call Sign M1BTI, Located in Manchester England.
Locator square IO83TK
Chairman Of Trafford Radio Club. Club Call Signs G0TRG & M1BBP
Located at Umist, University Of Manchester Institute For Science And
Technology
Share What You Know, Learn What You Dont.

> Hi Guys, Just to use my tuppence worth. A car isn't a faraday cage. Take
> any hand held device used inside the vehicle like a hand held amateur
> radio, PMR 446, a mobile telephone, gatso detectors, a gps satellite
> detector and your on glass antenna for your radio, is inside as well.
> All of these work within the vehicle, so any signal that can be received
> can be transmitted. A car isn't an effective faraday cage atall.

The point I'm making here is, a car isn't a faraday cage, transmitting
or receiving signals is perfectly plausable.
Naaah I couldn't accept Darlings theories would work in any manner he
has given. He needs to go back to school and take his think tank with
him. Makes you wonder is it all scare tactics for some given reason??
May be to have people like our selves think for them; as we are doing
here. Are you lurking on this NG Mr Darling?


> Amateur Radio Call Sign M1BTI, Located in Manchester England.
> Locator square IO83TK
> Chairman Of Trafford Radio Club. Club Call Signs G0TRG & M1BBP
> Located at Umist, University Of Manchester Institute For Science And
> Technology
> Share What You Know, Learn What You Don't.

On 2005-06-17, Jeff <[email protected]> wrote:

> True if that were the case, but what about starting your journey from there,
> or coming from a junction where both roads intersect? Or the signal being
> lost and then re-acquired in a incorrect position after an outage some
> considerable time later?

Jeff, forget it, it's a non-issue, they'll just use the same methods
that the manufacturers of road navigation gear have been using for
ages. Just because we can't regurgitate them here in a landrover
newsgroup doesn't mean that it's not possible, if it wasn't possible
then road navigation systems wouldn't be as useful as they are.

--
For every expert, there is an equal but opposite expert

On Fri, 17 Jun 2005 14:49:52 +0100, Dave Piggin
<[email protected]> wrote:

>
>
>> Hi Guys, Just to use my tuppence worth. A car isn't a faraday cage. Take
>> any hand held device used inside the vehicle like a hand held amateur
>> radio, PMR 446, a mobile telephone, gatso detectors, a gps satellite
>> detector and your on glass antenna for your radio, is inside as well.
>> All of these work within the vehicle, so any signal that can be received
>> can be transmitted. A car isn't an effective faraday cage atall.
>
>The point I'm making here is, a car isn't a faraday cage, transmitting
>or receiving signals is perfectly plausable.
>Naaah I couldn't accept Darlings theories would work in any manner he
>has given. He needs to go back to school and take his think tank with
>him. Makes you wonder is it all scare tactics for some given reason??
>May be to have people like our selves think for them; as we are doing
>here. Are you lurking on this NG Mr Darling?
>

Voters thinking for themselves? That's not very New Labour is it?


--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'77 101FC Ambulance aka "Burrt"
'03 Volvo V70

Oh well back to the spray on mud then

Or Klingon cloaking technology.



--
Larry
Series 3 rust and holes

"Tim Hobbs" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 16 Jun 2005 19:45:43 +0100, "Larry" <[email protected]>
> wrote:
>
>
> Oh yes it does... You just take the same technology used by traffic
> light cameras to sense the presence of a vehicle. If the beacon
> doesn't have a signal and there is a vehicle there, you photograph it
> and issue a fixed penalty.
>
>
> --
>
> Tim Hobbs
>
> '58 Series 2 88" aka "Stig"
> '77 101FC Ambulance aka "Burrt"
> '03 Volvo V70

On 2005-06-17, Tim Hobbs <[email protected]> wrote:

> My vehicle tracking system sounded a dangerous driving alert the other
> day. I was doing 144 mph in our office car park. Even better, I was
> sat at my desk with the keys in my pocket....

Yes, my Garmin ETrex mounted in the landy put my peak speed at over
3,000 MPH on one trip, I know I've fitted a Fearns intercooler but I
doubt the accuracy on that one I'm afraid!

--
For every expert, there is an equal but opposite expert

On 2005-06-17, Larry <[email protected]> wrote:

> Or Klingon cloaking technology.

Would make parking in the multi-storey interesting! Not to mention
getting back to the car again..

--
For every expert, there is an equal but opposite expert

On 2005-06-17, MVP <mr.nice@*nospam*softhome.net> wrote:

> How the hell can a reciever jam a gps signal?

A receiver can generate frequencies of its own due to the process of
demodulating the signal, e.g. mixing the incoming frequency down to a
constant lower frequency before amplification and demodulation. This
can cause radio interference, and is how TV detector vans are able to
find a telly and tell you what channel it's on.

Normally it's not a problem but for very weak signals such as
satellite signals it could cause a problem. I've not noticed it yet
but I've not looked.

> Now a transmitter yes, granted.

The line between transmitter and receiver is entirely arbitrary ;-)

--
For every expert, there is an equal but opposite expert

In message <[email protected]>
"Jeff" <[email protected]> wrote:

> > That could be verified by sanity checking - implausible data could
> > be run through an expert system (as used very efftively by insurance
> > companies), and in the worst case simply generate an error for human
> > intervention. How that should be dealt with is a political matter,
> > not technological.
> >
>
> How can you sanity check, say a 100m error, when a road exists at that
> location??
>
> Jeff
>
>

The system knows which road you are on, suddenly it's told you
are on another road for a few seconds, or more likely, some
random swapping between the two. By monitoring the last x
transimissions it will be possible to be very (>99% I say)
certain which road you really are on.

Error correction in comms can detect and correct 99.95% of
errors, and I can see that tracking could be even better,
since the next position has a finite number of possibilities
that make any sense at all.

Richard
--
www.beamends-lrspares.co.uk [email protected]
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Helping keep Land Rovers on and off the road to annoy the Lib Dems

>> How the hell can a reciever jam a gps signal?
>
> A receiver can generate frequencies of its own due to the process of
> demodulating the signal, e.g. mixing the incoming frequency down to a
> constant lower frequency before amplification and demodulation. This
> can cause radio interference, and is how TV detector vans are able to
> find a telly and tell you what channel it's on.
>
> Normally it's not a problem but for very weak signals such as
> satellite signals it could cause a problem. I've not noticed it yet
> but I've not looked.
>


Exactly..... I have a scanner that when tuned to a particular frequency will
jam a GPS at up to about 30' !!!

Jeff

>
>> My vehicle tracking system sounded a dangerous driving alert the other
>> day. I was doing 144 mph in our office car park. Even better, I was
>> sat at my desk with the keys in my pocket....
>
> Yes, my Garmin ETrex mounted in the landy put my peak speed at over
> 3,000 MPH on one trip, I know I've fitted a Fearns intercooler but I
> doubt the accuracy on that one I'm afraid!
>


Yes this is the problem... a 95% success rate for a navigation system is
perfectly adequate, but 5% of people being mis-charged is a recipe for civil
unrest!!!!!

Jeff

Dave Piggin wrote:
> The point I'm making here is, a car isn't a faraday cage
......at the wavelengths of interest.
Steve