Garmin Iii+ Tracking Issues

[+smenzel]

Hey Folks --

 

I've been without a GPS lately so I haven't been doing much caching. Yesterday I bought a used Garmin III+ for $70. Seems like a sweet deal. Everything seems to work except that it the GPS coordinates appear to be a bit off. Here's what I mean.

 

I went out searching for GCJZ61 Bassett Pond Blue Berries this afternoon and the blasted GPS sent me south of the road when the cache is actually north of the road.

 

Thinking I might have made a mistake, I went to a cache whose location I happen to know (and is fairly easy to find). While standing right on top of GCD53A Merry Cache the GPS told me I needed to look another three tenths of a mile southeast.

 

Then I double-checked the waypoint I had created for my house. The coordinates created using this GPS were a good deal diffferent than the ones I had from my previous GPS (eTrex).

 

Am I dead in the water with this unit or is there some way to calibrate it? I don't have a lot of time because of the return policy where I bought the unit.

 

Thanks for any help.

 

Sandro

[+IBcrashen]

sounds like you have it set on the wrong map datum. My 3+ is borrowed out to a friend so I cant tell you how to change it.

[peter]

Yes, I agree with the cause of the problem. The two things that most commonly cause location errors are the map datum (should be set to WGS 84) and the location format (should be in degrees and minutes - HDDD° MM.mmm'). Errors of up to a few tenths of a mile are usually datum related while the location format frequently creates larger variations. But check both on any unit you get used or if someone else has had a chance to change the settings.

[+Sputnik 57]

I agree. Sounds like your datum may be set to NAD27 or something. Make sure your datum is set to WGS84, and that your coordinates are in the format of h dd mm.mmm (hemisphere, degrees, minutes.decimal minutes).

 

Edit: Peter types faster than me.

Edited October 21, 2005 by Sputnik 57

[+smenzel]

My unit was set to Bellevue (IGN) which, according to the PDF manual from Garmin (page 92) is Efate and Erromango Islands.

 

Restoring defaults set the unit to WGS 84. I'm off to test this setting. Thanks.

[+smenzel]

Thanks for the help. So far, so good. My house registers extremely close to where it used to be with my previous GPS. I'll try a cache ot two tomorrow and see what that yields.

[marty621]

Find an accurate benchmark near you and check the unit against the coord's published for that mark. Do not use a mark that has "scaled" coords.