AndyC_772

iTrader: (2)

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pslewis

Careful doing that - you'll get a migraine!!

Pete

_Meridian_

iTrader: (1)

Unless I'm very much mistaken (not impossible) the speed reading of the car comes from a radar gun; the lines (and thus the double flash) are there to provide corroboration, not the main evidence. What Mr Edgar is attempting therefore, is simply to muddy the waters - standard defence trick #3: if you haven't got any real defence, try confusing the cr*p out of everyone. I'm assuming the radar is saying he was over the limit. Out of interest, does anyone know if the radar and flash calculation agree? If not, what's the difference? If if so, what the **** is he banging on about? It's a bit like someone blowing 105 on the breathaliser, then complaining about the fact that a policeman said he looked "very drunk" rather than "pretty drunk".


M

STi wanna Subaru

iTrader: (1)

If they are over-reading speeds then that statement is bollox! Still I'm pretty certain those disability carriages only have a top speed of 15mph so you’re safe whatever Pete

pslewis

Meridian - a bit of sense, at last

Pete

ps. They work on K band radar - the flash is, as you say, to back-up the evidence

pslewis

Ok, lets get some real info down:-

Gatso cameras are activated as the vehicle crosses a radar beam and takes two photographs half a second apart, whilst Truvelo cameras are activated as the vehicle travels over sensors in the roads. On-board computers instantly calculate the distance travelled between the two points.

It's basic maths - distance travelled over time = speed

The white line markings on the road surface provide a secondary back-up check, verified by an operative who examines the film taken by the camera.

Every camera is checked to ensure it is properly calibrated and working every single time it is placed inside its yellow housing. Twenty-four hours or so later, when the camera and film are removed, the camera is checked again to ensure that it has been working properly. In addition, the camera conducts a self-test every time it takes a photograph. Furthermore, every single photograph is subsequently checked 'by eye' by an operative.

The calibration and checking regime is rigorous in the extreme to ensure that no innocent motorists are accidentally caught by the cameras. In other words, the cameras are only capable of catching speeding motorists. So, if they catch you, you have been speeding!

The photos and flashes are just a back-up

He hasn't a hope in hell of getting off - throw your money down the drain, it will be more use!!

Pete

Sprint Chief

How exactly will moving affect the measurement of the time between two flashes?

Lets say he waits by the machine until a speeding car goes by (it does happen you know, otherwise the camera wouldn't be there) and measures the time between the two flashes?

Not that hard to work out is it?

Sprint Chief

The radar measurements are prone to error and cannot be used on their own as evidence in court. The photos are not just back up, they are essential to the case.

PS. Brunel has only been a university for the last 40 years or so. OK that might make you say late fifties early sixties if you were one of the first but suggests you ain't quite as old as you claim to be!

AndyC_772

iTrader: (2)

It doesn't - unless you count the difference in flight time from flash to car and back to the camera due to the car being 0.5 sec further away at, say, 30mph. The speed of light is about 186,000 miles/sec - work it out

pslewis

What stopped me doing my BSc when I was 50? You really MUST start applying logic to your posts!

Pete

ps. when you are caught in a police speed trap there are NO cameras and you don't GET-OFF!! They only need the RADAR evidence to do you - the film is so a human can check that they are not fining innocent motorists!

Sprint Chief

Ah so he measured the first flash, moved at near the speed of light to a point 39,000 km away, then measured the second flash.

What a blundering fool!

Sprint Chief

True... you could have been a "mature" student... just the concept of pslewis and mature was too much of an oxymoron to contemplate

Sprint Chief

The problem with gatsos which makes them different to police hand held radars is that they can be so easily triggered. My guess is that they have a very broad beam and a cheap crappy CW radar without single side band mixers that measure Doppler shift at baseband. (I assume your electronics background should ensure that all makes perfect sense )

As a result they can't differentiate positive and negative speed and the broad beam means they can be triggered by something other than the vehicle being monitored, I'm sure many here will have triggered a camera going in the opposite direction. I don't know what the tx beam pattern is but it may also have sidelobes that could result in a false trigger. You don't get done for it because you can't be seen by the camera which has a narrower field of view.

So the radar from the gatso is unreliable. You cannot be done without backup from the two photographs.

boomer

*****,

your diatribe seems to have an awful lot on content from http://www.safetycameraswestyorkshire.co.uk/info.asp and probably many more cash for cameras partnership web-sites.

Time to tell nanny to turn over the page

mb

wez_sti

Fact is that the white lines and second picture obviously are vital to speeding prosecutions in the case of Gatso's otherwise they wouldnt spend the time/money/effort putting the white lines down and doubling the amount of film they use by taking a second pic.

If the timing is wrong then the suggested speed would be wrong.

pslewis, if ANY of your supposed qualifications were real, then you would of known that a few metres travelling at the speed of light is something you can leave out of the equation.

Besides the fact he was only measuring the time between flashes anyway...

Its great to see you make a complete idot of yourself.


Wez
(an actual Physics A Level + others.)

wez_sti

PMSL!!

Thank you so much for that, just shows that all of his previous 'intelliigent' coments were purely copied and pasted from the writings of people who actually know what they are talking about!


pretend we are having a conversation about the theory of relativity..

pslewis says
copy/-
One of Einstein's great insights was to realize that matter and energy are really different forms of the same thing. Matter can be turned into energy, and energy into matter.
For example, consider a simple hydrogen atom, basically composed of a single proton. This subatomic particle has a mass of

0.000 000 000 000 000 000 000 000 001 672 kg..../-paste





HAHAHA!!!


YOU SUMMED IT UP PERFECTLY, *****!

Wez

pslewis

Not a REAL ACTUAL 'A' Level !!! Don't make me laugh kiddie

Pete

wez_sti

Did i miss something amusing in your post?

pslewis

Nothing wrong in using reference works from the internet!

You don't think I will expend too much energy on arguing with losers do you? If I can cut and paste to win my point I will

Ok? Mr Real Actual 'A' Level?? PMSL come back when you're older!

Pete

Sprint Chief

I thought an A level was slightly higher than anything from Brunel university these days?

johnfelstead

MUCH Cleverer? that just about sums up how smart you havn't been in this thread Pete.

My understanding is you cant be convicted of speeding on a Gatso unless you are 11MPH over the limit, is this chap being done for 41 in a 30? I would sugest this is because they already know Gatso's have poor calibration so have this 11MPH buffer to ensure no one gets falsely acused.

I would expect the magistrates have a document with the equipment they are allowed to accept as concrete evidence, and to get a device like a Gatso excluded you would have to start a new case in court to get this device struck off the accepted device register. I dont know if that is the case but it would make sense to me to do things that way.

pslewis

Have you seen how easy it is to get A levels and Degrees these days???

Not like in my day when it meant something - sad thing is ..... the people who get them actually think they still hold the old value - they don't!!

Pete

wez_sti

It was in reference to your blatently false qualifications you quoted. The funny thing is, you've relied on cutting/pasting, yet you've still been proved completely wrong on each of your points in this post...i know your old but bloody hell!

BTW

A) How do you know my age? i could of done my A Level at any age, as you so quoted earlier. Could be older than you for all you know


B) On what basis have you concluded i'm a loser? You dont know my educational background, job, earnings, IQ, political stance, anything?



to call you ignorant would be the same as calling Ian Dowie ugly.

pslewis

Interesting, is that true or just made up??

I would like to see where that has come from ..... if its true, then I would say he has no hope of proving he wasn't speeding then - thats 30% over the posted 30mph limit!

Pete

wez_sti

I'll give you that, getting an A'Level in your day would of been much harder, probaly because they didnt exsist...


I worked hard for my Physics A'Level, widely recognised as one of the hardest A'Levels. Plenty of 'boffs' dropped out of the subject.


You certainly wouldnt be able to get one, not with your show of knowledge so far.

Sprint Chief

Yep, I agree, Tony Blair and co have just watered down the value of these things

Anyway get back on topic "old chap" hope my introductory lecture on how the gatso radar system works was of help Or didn't you follow it? Not too complicated I hope, I could make it a bit simpler if you want. Had the Doppler shift effect been recognised when you got your degree?

pslewis

Yes, but, come on!!

Throwing in an 'A' Level as some indication of Scientific Intelligence is laughable ............. and only a kiddie would do such a thing!

And you are a loser because you don't agree with me - as I am a winner, you must be, by definition, a loser! Thats simple isn't it?? Even for someone with a REAL ACTUAL REALLY GOOD REALLY REAL ACTUAL 'A' Level?

Pete

johnfelstead

I cant remember where i got that info from, it was a long time ago when Gatso's first came out about 1991 i think, i normally only remember stuff like that when it has some foundation in truth. Might not be the case on newer trevelo's etc.

pslewis

Dopler Shift Effect??

Well, yes, you could have made it easier to understand, something like an example using cars maybe?

Like:-

Here's how to understand Doppler shift.

Let's say there is a car coming toward you at 60 miles per hour (mph) and its horn is blaring.

You will hear the horn playing one "note" as the car approaches, but when the car passes you the sound of the horn will suddenly shift to a lower note.

It's the same horn making the same sound the whole time.

The change you hear is caused by Doppler shift.

That would have made it easier for me

Pete

Sprint Chief

Wow

Nice explanation.

Now how about single sideband mixers