Inaccurate Etrex Legend Cx?

[+Silny Jako Bek]

I just bought a new Garmmin Etrex Legend CX this week. Today I went out with two other cachers and my unit was consistently at least 40' off. Their Garmins would zero out right at the cache site and I would be standing somewhere else, obviously searching fruitlessly for a cache that was not where my Garmin said it should be. What the!?!

 

Anyone know of any obvious things I can try before I contact Garmin on Monday? Anyone else have this problem?

 

Thanks!

[+ghs]

Well, does that particular unit have a "battery saver" mode and a "normal mode"? Which one were you using? (It's a little more accurate in "normal mode.") Did you try turning your GPSr off and on again and stand still a little so it can stabilize? It's never a bad idea to call Garmin and see if they have any suggestions (I've found them to be very responsive via email), but I'd "play" with it some more before getting too worried. You might find another time that it's your GPSr that gets you closer than someone else's. One thing you could try is, go out some place. Turn your GPSr on in its most accurate mode. Let it stabililze. Mark a waypoint for that location. Move significantly away from there, turn your GPSr off and on again, and then see if you can navigate to the waypoint you just made.

Edited February 19, 2006 by ghs

[+Skidamarink]

Is your Map Datum set to WGS 84?

[+Silny Jako Bek]

Yes to both of your questions!

[Hertzog]

Is your Map Datum set to WGS 84?

 

This is gasping at straws a bit, but since you answered "yes" to this question, were your friends and the cache position also in WGS 84?

 

The only other thing I can think of is the quality of satellite reception. You didn't indicate what Gamin models your friends were using, or the quality of reception. If all were getting good reception I wouldn't expect that to be a factor, but under marginal conditions it might make a difference.

[+Hynr]

Another thing to try: when a GPS is first powered up it needs to acquire an almanac of GPS data from the satellites. Leave it on exposed to the satellites for about 20 minutes. Then try to see if you get improved positioning.

[+Kewaneh & Shark]

Along with the quality of signal reception theory: different models of GPSr may have different types of antennas, which can affect that quality of reception. Make sure that you hold the GPSr away from your body and that the top of your GPSr is generally pointed upward for the best signal reception.

 

WAAS could have also been a factor. Did your friends have the WAAS capabilities turned on on their units while yours was turned off (or vice versa)? If your ETrex has WAAS capabilities, turn it on and the inherent error of your GPSr will be about cut in half.

 

- Kewaneh

[+ghs]

If you tried the experiment I suggested and that appeared to work, I'd suggest trying it again later today to see if it still works. (If you do have some sort of systematic bias in your receiver, being able to navigate back to the same "wrong" point within a few minutes of defining the waypoint might not prove anything. However, there's a good chance that the effect of a systematic bias would still be affected by satellite geometry. If there's sufficient time for the satellite geometry to change in between the two navigation experiments and you can still get reasonably close to your waypoint, that would tend to indicate that your unit might be working as designed.)

Edited February 19, 2006 by ghs

[+Silny Jako Bek]

I tried the suggested "mark a waypoint, turn it off, go away and come back" today and found the Garmin was more accurate today. I did the test along with my previous GPSr, a Magellan SportTrack Pro, anad most of the time they were showing the same distances from the marked point. Feeling enboldened, I even went and did a few caches by myself today and found them without problem (although right as I narrowed in on one cache site, the distance to went from 4 feet to 265 feet for a couple seconds, then to 15 feet). I'll make sure I don't have this inaccuracy problem again by trying it out often in the next week before I contact Garmin. Thanks fofr all the suggestions - I hope this was just a transient problem!!!!

[+tourinct]

When I first got mine about three weeks ago, I was wondering the same thing. But after using it awhile am not having any problems. Though it does seem to take longer to settle than my GPS60 did. By the time I sign log and rehide it is usually reading single digits.

[+Silny Jako Bek]

When I first got mine about three weeks ago, I was wondering the same thing. But after using it awhile am not having any problems. Though it does seem to take longer to settle than my GPS60 did. By the time I sign log and rehide it is usually reading single digits.

 

Good to know. Hopefully I haven't made a mistake in purchasing the Legend CX.

[+ghs]

Even if there's something not quite right about your particular unit, I wouldn't conclude from that that you made a mistake regarding the model. I've seen posts from others here with etrex Legends that appear to like them. I met another geocacher with some variety of the etrex Legend. He didn't seem to have any complaints. He said he quite often gets close to the cache and his distance reading shows "0". My emap almost never shows a 0 distance. Good luck. Don't be reluctant to call or email Garmin. (As I've told them, I've found their customer service to be better than that of anybody else I've dealt with.)

[+Silny Jako Bek]

Okay, I've used the unit for another week and I am still having problems. When I mark a waypoint and come back later, the unit says I am 40-60 feet away from the marked spot. I think this is unacceptable. The only response I have had from Garmin is that I should make sure that WAAS is enabled (which it is and has been). I am starting to get annoyed...

[peter]

... I should make sure that WAAS is enabled (which it is and has been). I am starting to get annoyed.

Are you getting WAAS correction data when your LegendCx is leading you 60' astray? I.e. do you see the little "D's" on the signal strength bars on the satellite page?

[+tourinct]

Just after I had rationalized no problem, I had an issue yesterday. Pulled into parking and was about 140 feet away. Just to check I pulled out the 60 and it showed the same. Shortly thereafter, the etrex was showing .23 while the 60 held steady. Batteries were about done on the etrex so I shut her down and used the 60 to find. But, not sure there isn't a problem, need some weather out of the 20's to get in the field and really test.

[blang]

... I should make sure that WAAS is enabled (which it is and has been). I am starting to get annoyed.

Are you getting WAAS correction data when your LegendCx is leading you 60' astray? I.e. do you see the little "D's" on the signal strength bars on the satellite page?

 

I'm with peter on this one; have you actually acquired a WAAS satellite, given the unit a little time to download pertinent data from the sats and then seen the 'D' on your signal bars?

 

How many satellites do you typically acquire? Have you compared the number of and number on the sats with your friend's GPSr? What models are they working with?

[+Silny Jako Bek]

I'm with peter on this one; have you actually acquired a WAAS satellite, given the unit a little time to download pertinent data from the sats and then seen the 'D' on your signal bars?

 

How many satellites do you typically acquire? Have you compared the number of and number on the sats with your friend's GPSr? What models are they working with?

 

I generally have 9-12 signal bars, and usually all but a couple have the "D". The models that my caching friends had with them were a Garmin Geko and a Garmin Forerunner.

 

And now, to add to the problems, I seem to have "lost" my downloaded map data. Where did it go? It was there yesterday?

[+DangerJudy]

My Legend CX is accurate - cached with someone with a Vista C and someone with a Magellan color screen model, dunno which one. We all had similar readings. I suspect it's your unit.

[+Fudog1138]

First off I'm new to GPS units.

For starters are you using alkaline, NIMH, or Lithium Ion batteries?

You may have a bad battery that's causing your unit to malfunciton. It may be worth changing them out. It would be an inexpensive test. I've bought Energizer Lithium Ion batteries for my digital camera before and had it do all sorts of strange things. The batteries show 1.6 volts, I change them out with another set and bam, they work fine.

Just a suggestion. Best of luck.

[+RGS]

I just bought a new Garmmin Etrex Legend CX this week. Today I went out with two other cachers and my unit was consistently at least 40' off.

 

I'm having the same problem with my Legend Cx. Went with a friend last week to create WP's for an event we are having and i used my Cx and he used his Vista. Creating 11 WP's throughout the park, We were always 60-70 feet different. The N coords were ALWAYS the same, or 1 digit off (6 feet)However, the W coords were always about 60 feet off (W 90 35.123 and W90 35.133) Mine was always about 60' too far west.

 

Since that was really the first time I had compared my Cx with another GPS, I compared it with my original Legend today with both sitting on the driveway at my house. Again, the Cx was about 60' West of the coords with my old Legend. Looking for caches with the Cx was putting me off about 40-50 feet but I blamed that on normal tree cover and GPS errors.

 

Neither has WASS turned on since it's normally hard to get a WASS lock so It's never turned on. Batteries were good, Datum was WGS84, etc.

 

I was going to wait for a SW update but maybe I'll give Garmin a call on Monday.

[+Silny Jako Bek]

An update:

 

I returned my "faulty" Cx to the retailer after a number of unsatisfying communications with Garmin where they eventually (begrudgingly) admitted that there could be a problem. I received a replacement unit and it works great! So there really was something amiss with the first one.

 

To the previous poster: I would return yours as well for a replacement. It seems there might be a reoccurring problem with these units.

 

Thanks to all for their excellent input!!!