How do I calibrate my Garmin III+ ?

[Guest a_calder]

I have noticed that my Garmin III+ seems to be way off when visiting a number of recent caches.

 

Is there a way to calibrate the unit so that I can be sure I am getting totally accurate info?

 

Also, I noticed that Geocaching.com is using the WGS-84 method when listing lat & long and in the Setup area of my unit, there are options for what appear to be hundreds of others. There is even a setting for 'Nad-27 Canada'. Should I be using that up here in Canada? Why or why not?

 

Thanks for anyone who can answer these two questions.

 

Alistair.

[Guest k2dave]

I would stick w/ WGS-84 - that's what is requested when you post your cache.

 

as for calibration - no but there is a way to reset internal tempature calabration - this will clear a table of values used to correct position based on the internal circuit temp.

 

Another thing I have noticed about my 3+ is it seems to get better the more I use it (or maybe I just learned to use it better).

 

If you use the gps in places where you don't get a good signal (and the 3+ is one of the best at getting a signal) then the placer proabally had trouble getting a signal and could be off.

[Guest alexm]

I had a similar problem with my Magellan recently.

 

Seems I had 'tweaked' the settings a bit too much, and tweaked a few things I shouldn't have been twucking with.

 

I don't know if the Garmin's have a 2d/3d elevation mode switch, but I'd definitely try to 'reset' or 'initialize' the unit and see if using it's defaul settings that it's any better.

 

Turns out I put mine in 2d mode. Seems 2d mode should only be used when you exactly where you stand and what your elevation really is. Otherwise, 700 feet of bad elevation = 300 feet of trailblazing.

 

Hope this helps!

[Guest k2dave]

IIRC the 3+ will only use the inputed elevation when it's in 2d mode. If it can get 4 sats then it automatically switches to it's own elevation - but maybe you can override it.

[Guest Gliderguy]

I had a III that had sat for months with no batteries installed. When I fired it up to compare a fix with my III+ that had been used regularly, the coordinates were several tenths of a mile off. After letting the III run continuously for about half an hour, it syncronized with the III+ and they both gave readings within a few feet of each other. I suspect that the unit has to download the entire almanac when it has been off for a while, and that this takes anywhere from 15 to 30 minutes of continuous on time to achieve. If you turn your unit on, get a fix, and turn it off a lot, your almanac data could be way out of date and you just need to let your unit sit motionless with a good view of the sky (4 sats or more strongly locked) for about half an hour or so.