Am I driving too slow (1 Viewer)

Jul 5, 2013
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ALL GPS satellites are military run, therefore they can change things as and when they want ( and they do ) ever wondered why you have a great signal one second and then the next none!!!! - therefore you cannot rely on the speed displayed to be accurate NOT EVEN to +/- 0.5mph at worst.
That sounds like a conspiracy theory. They are used and relied upon for so much in civilian world, including aviation, shipping trucking etc, that they do not muck about with them. In fact if you pay them some (a lot of) money they will even unlock to allow pinpoint accuracy within a few millimetres. That is used for all sorts of things nowadays.

And anyway, as others have said there are plenty of alternatives to the US military system now. And if you were correct my sat nav would be forever losing where it was, but it doesn't most of the time. In fact it only happens in cities with lots of high rises, because of the canyon effect or when under tree cover in the summer. And if the signal is lost it is not be able to display the mph anyway.

As I said they are much more accurate than the speedo for the reasons I have given.
 

Vlad The Impaler

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Are you sure about this?


JJ :cool:
Well JJ I have no trip computer to tell me my mpg but do more or less the same routes thought the year . On my annual run to Scotland if I sit at 60 all the way I can get there on a full tank if I press on a bit I have to stop at a garage about 30 miles further away on a 7 hr drive I'd say that's negligible !


Vlad
 

Vlad The Impaler

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Well JJ I have no trip computer to tell me my mpg but do more or less the same routes thought the year . On my annual run to Scotland if I sit at 60 all the way I can get there on a full tank if I press on a bit I have to stop at a garage about 30 miles or so further away on a 7 hr drive I'd say that's negligible !


Vlad

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Vlad The Impaler

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Not the case In my experience I ,have driven a merc sprinter lwb for work for many year .Over that time I've had my fair share of punctures whilst driving front and back,I've never had a tyre explode !
If your switched on you'll sense the judder slow down and pull over.
When I think about it apart from our low loader driver who has wheels a plenty ,no one on our firm in the 18 yrs I've been there ,has had a blow out
And kissed their arse goodbye!

Vlad
 
Feb 24, 2013
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not long enough
we might have a different build to others, but without any doubt if we increase speed from 55 to 65 we will use loads more fuel, been to 70 once and excess fuel consumption flow curve continued to get even steeper, didn't look at on board computer, the gauge was dropping fast enough to slow me down

I am not telling anybody not to drive so fast, just don't exaggerate the fuel consumption too much :D

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Jaws

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I sit at 52 mph.. on the GPS.
The GPS has been checked and as long as we have clear skies is accurate to plus or minus 1.2mph ( compared to the speedo which is a constant 8 to 10% generous )

If I travel at 60 I drop 2 or 3 mpg.. Not a lot some folk will say, but when you are doing trips of 3000 miles the numbers soon stack up
At 52 mpg I average 24 ( but that may well change as I have just fitted one of Torquing Diesels control box's .. last time I used one I gained an extra 2+ mpg ), at 60 that drops to 21, and at 70, down to 18 to 19 mpg

But then, I do have a real motorhome and not a converted builders van !! LOL !!!
 

voyagerstan

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I sit at 70 ish and the extra fuel used between that and 60 is next too no
I couldn't help thinking he was the mad one for driving so slowly and causing the problem in the first place!

Re speed cameras in France I've been flashed by my fair share but never had anything through the post,so sleep easy.

cos the froggies wo'nt pay DVLA for driver information .:whistle:STAN


Vlad
 

Vlad The Impaler

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You've hit the nail on the head Jaws when I go away I take two young school kids with us and have to be back,it's a kind of job and knock,hence the builders van .
But on the plus side the reliability a builders van affords us means it can be loaded up to the max and thrashed like a tw&t.On my last trip to France we had a Fortnight away and about 3 days on the road and covered approx 2200 miles as said not worried about fuel consumption.
I can remember first buying my Mh and worrying about fuel consumption ,then hearing about people who sit behind lorries to follow their slipstream to save ? mpg :doh: Or you get those who swear blind at sticking to 50 mph.
Well I won't apologise for being me ,I'll drive like I like ,stop where I want and
Thank god I'm in a builders van !
Could be worse could be in a yank tank


Vlad

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Jaws

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D Q.. I am a bit unsure you know how a GPS works..
They ( the owners of the sats ) can:

Reduce or increase gain ( output power )

Reduce or increase beam pattern thereby changing positional accuracy

What they cannot ( for practical reasons ) is change the on-board telemetry clock time as THAT is controlled by the atomic clocks dotted around the world ( Wiki is your friend if you want more info as to how the clocks are controlled with maser pumps )
From memory they are accurate to less that 10 to the minus 9 seconds per day and autocorrect ( again from memory ) every 23 hours ( lord knows why 23 hours )

Sooooo what is all that squit about ?
Basically the speed on the GPS ( as said, providing you have clear sky ) is worked out by the times coding from a minimum of 6 satellites.
For your speed to be registering wrong the time coding of SOME of the sats would have to be changed by about 10 to minus 6 points ( and the result would be a right give away as the GPS would suddenly put you some considerable way from where you actually are ! )

There is also the legal side of the issue
If ANY instrument designed to indicate vehicle speed, it COULD be set to read generous, but cannot be set to read mean.
Why ?
Because if you get pulled for speeding and can prove the device being used is under reading, the kick back would be mind blowing.

Yes, you could still get nicked for speeding but you could, with absolute alacrity take the manufacturer of the device to court and sue them sockless !!!!
And once ONE person had a claim every tom dick and harry would jump on the band wagon !!


Basically, IF your GPS is in clear sky, you can trust it to be pretty accurate ;)
 

Jaws

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You've hit the nail on the head Jaws when I go away I take two young school kids with us and have to be back,it's a kind of job and knock,hence the builders van .
But on the plus side the reliability a builders van affords us means it can be loaded up to the max and thrashed like a tw&t.On my last trip to France we had a Fortnight away and about 3 days on the road and covered approx 2200 miles as said not worried about fuel consumption.
I can remember first buying my Mh and worrying about fuel consumption ,then hearing about people who sit behind lorries to follow their slipstream to save ? mpg :doh: Or you get those who swear blind at sticking to 50 mph.
Well I won't apologise for being me ,I'll drive like I like ,stop where I want and
Thank god I'm in a builders van !
Could be worse could be in a yank tank


Vlad

Could be MUCH worse.. Could be a Swift !!!! ROFL !!!!!!!!!!!
 

Vlad The Impaler

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Thank fu£k as a builder I wear good waterproofs ,or I would have been unprepared for a comment like that!


Vlad
 

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