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Selective Availability (SA)?

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Hi Everyone out there ,


I own a magellan GPS 320 its about 3 months old and i've had a few problems ,


the thing is every so often my gps goes crazy ! it pin points me upto 5miles away . it always seems to happen at the wrong moment as well .


I've taken this paragraph from the magellan FAQ section on there site :-


"Q: What is Selective Availability (SA)?

A: SA is an intentionally introduced degradation in the accuracy of civilian GPS by the United States Department of Defense. SA errors can degrade the GPS accuracy up to 100 meters. However, this error is adjustable and random. Typically, errors of 30 meters or more are not unusual. Now that SA has been removed, typical GPS position accuracy is approximately 15 meters (50 feet)."


my case seems a bit more extreme than this ,

is there a fault with my gps ?

Does any other magellan user suffer from this ?

do any garmin users encounter this ?


HELP ME , Its Getting annoying


P.S. i bought the thing when on holiday in Australia so it'll be hard to return it :-(

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As the manual says, selective availability has been disabled, so that is not the problem. The only other thing I can think of that might produce a 5 mile error is poor reception. Does it happen when you are under trees or in built up areas?


Another possiblity is that it might default to an Australian datum (you bought it in Oz), but that would give you a consistent error - it would never be right.




The second ten million caches were the worst too.


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5 Miles is a big problem - SA would account for 100 meters if it was switched on. Sounds like something has gone wrong with the unit. You could try updating/reloading the onboard software,

post a message and have a look at the GPS-software board as someone else might have had the problem or else go back to the manufacturer.


You may have bought it in Australia but it is supposed to be a global system so they should support it globally - worth a try.



"We're not lost - we just don't know where we are"

London & UK Geocaching Resources: http://www.sheps.clara.net

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Or on the other hand you could sell the unit to someone without telling them of the problem and use the money to buy a Garmin ETrex.........Or would that be poor salesmanship. LoL.


All the best with it though.





Watch out its a Golfcourse... (Team Dan + Pid)

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I've currently have the newest software on the gps version v3.15 for europe so we can rule out the Australia stuff i think , and it is set too wgs84 .

there isn't really a time that i could say it does it , i can be in the woods or in a clearing ,


it happened when i was looking for the " take a walk to visit carl " (not a plug)cache . and if you've visited that you'll know its in moorland with perhaps excellant recption capabilities e.g. no trees , clear view of the sky . and the weather was great .


I've e-mailed Maggellan so we'll see what they say about it .


Thanks again for you're suggestions

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Just a quick message


I had a reply from magellan and they gave me the number of a company called Comar in the isle of wight .

I rang them and they said even though my unit is under australian warranty they will exchange it for me F.O.C. Which is good

I was out caching the other day and i got a 145mile error . and today it went absolutly mental all day . lets hope my new unit doesn't do this :-)

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