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Re: speedometer not properly calibrated
"Ray O" <rokigawa@tristarassociatesDOT.com> wrote in message
news:c4279$438cd248$44a4a10d$20195@msgid.meganewsservers.com...[color=blue]
>
> "Gord Beaman" <gord@islandtelecom.com> wrote in message
> news:jdk8r1dvp0fho2m04ejsnskugaaa827uj8@4ax.com...[color=green]
> > "B. Peg" <bent_peg@worldnet.att.net> wrote:
> >[color=darkred]
> >>> How can you check if the speedometer is not properly calibrated and if[/color][/color][/color]
I[color=blue][color=green][color=darkred]
> >>> ask a mechanic to do it how much should it cost?
> >>
> >>If you belong to the Auto Club, they have a roving speedometer check
> >>vehicle. They post its location in their magazine, which is usually at
> >>one
> >>of their local offices. I believe it is a free check.
> >>
> >>The GPS idea is also good.
> >>
> >>B~
> >>[/color]
> >
> > But how accurate is the GPS?...I have a Magellan Meridan
> > Gold...not very expensive (or is expense a factor?)
> > --
> >
> > -Gord.
> > (use gordon in email)[/color]
>
> If the GPS is WAAS enabled, then it is probably accurate to within 10 or[/color]
12[color=blue]
> feet. Without WAAS, it is probably within 30 feet.
>
> --
> Ray O
> correct the return address punctuation to reply[/color]
Except he needs the accuracy measuring the speed, which isn't done by
evaluating the difference between positions, at least not typically:
[url]http://gpsinformation.net/main/gpsspeed.htm[/url]
As noted on the link, Garmin (a popular manufacturer, I have one of their
units) claims .1 mph accuracy. This probably depends on pretty good skyview
and satellite selection. On a highway in a fairly level rural location,
with no obstructions and the GPS placed where it can easily see the sky (or
at least the satellites currently in the sky), you'll get that accuracy. I
have a Sienna. If I put the GPS towards the front of the dash, it gets a
pretty good skyview. If it's reporting good positional accuracy, speed
measurement will probably be pretty accurate, too.
Got no money? Set your cruise to 60 mph and time mile markers over a
straight-ish 10 mile stretch of road. A stopwatch and I-80 in Nebraska are
handy for this.
Got $100 and an interest in radio, electronics, hunting, fishing, camping or
hiking? Get a cheap GPS and check your speed that way (have a passenger
actually work the GPS) and the GPS will provide entertainment later on. You
can use them in aircraft (after the pilot says electronics are OK - just
hold it up to the window), boats, woods, etc.
Got lotsa money? Get a mapping or navigating GPS unit.
To be sure you're using it right, check gpsinformation.net for more info and
be sure to read your product manual. GPS is not magic (it just seems that
way) and it does have its limitations. Look over gpsinformation.net BEFORE
you buy.
YMMV.
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