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poor Legend accuracy due to power lines?

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Hello all,


I've been geocaching since September 2002 but this is my first time on the forums. I have a question about Legend accuracy.


I got the unit in September 2002. The accuracy was OK at first (I could generally get 12-15 ft. accuracy). Then in December I went to a cache that was hidden right underneath a power transmission line. The GPS pointed me over 100 feet away (into a monster patch of thorns icon_rolleyes.gif) and we only ended up finding the cache by coincidence just as we were leaving. After that we went to look for another cache, that was hidden down the line under another tower - same thing, the GPS pointed me consistently to a point about 150 feet away.


Ever since then my accuracy has been shaky. Occasionally it works fine, but most of the time the spot indicated is about 40-50 feet off from the cache. It could be that the receiver is weaker under tree cover now than it was before.


Any suggestions? Does the unit need recalibrating? I think it might still be under warranty. I am inclined to return it because aside from the recent accuracy problems, the waypoint-marking function crapped out after about two and a half months and I haven't been able to use it since. I'd be grateful for any insight.





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Hello Sugar (I always wanted to say that and not get slapped) icon_wink.gif

Send an email to Garmin support with your question. I am sure that this has been brought to their attention before and they probably have some insight.

Fellow cachers will also chime in with their experiences.

Let Garmin know how much time you spent under the power lines...

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Upgrade the firmware if you haven't already. If you have, reflash it. I doubt the waypoint marking bit is hardware dependant, in which case a software reflash would fix it.


I doubt powerlines would affect your Legend. If it were a unit with a quad-helix antenna then I might think you were right. Word is that quad-helix antennas can be detuned when they are close to metal (for example setting your unit on the hood of your car). If that was the case, I could reasonably see how electo-magnetic radiation from a powerline would do the same.


However, the eTrex line all have patch antennas which I am told do not suffer from the detuning problem I described above.


A simple reflash could be your answer. Give it a try.


[This message was edited by GeneralBracket on May 07, 2003 at 01:50 PM.]

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Nothing that can be calibrated really. Powerlines can cause interference in themselves depending on the voltage and other issues.


Steel towers can be an "obstruction" in themselves and in conjunction with "interference" can combine to hassle any GPSr.


The cache your looking for isn't perfect either and all things being considered then it might all be normal. Might simply be circumstances (at this time).


Cheers, Kerry.


I never get lost icon_smile.gif everybody keeps telling me where to go icon_wink.gif

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I have used my Legend under high voltage power lines with no effects, temporary or permanent. Antennas cannot be permanently "detuned". GPSrs are radio receivers, and the presence of strong signals can overload the unit (or mix in the receiver), causing temporary performance problems. It may be possible to permanently damage your GPSr if you place it very close to an antenna transmitting at very high power.

The suggestion to reinstall/update the firmware sounds good.

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