Garmin Etrex

“I have an Etrex and whenever I am hiking in a mountainous area I seem to have problems locating enough satellites to fix my position. It is supposed to be not affected by tree cover but I dont know about being on the "wrong" side of a mountain. I sent e-mail to Garmin but havent gotten an answer yet. I was just wondering if any serious navigators in here could help.

Thanks”

“All GPS recivers can have some interferance from trees, to claim so is hogwash. A GPS recives the signal from satalites, they all get the same signal, which although is set to a frequency which minimizes the problems of stuff blocking signals, it is not 100% fullproof.

For one manufacturer to say their GPS will recive better under trees than another is like saying my mouthwash will make you breath fresher. Like I said, they all use the same signal. In order to get better reception, use the same principles you use when trying to get a good radio signa: seek high ground - line of site is important, avoid power lines and large metal structures, find clear spots in trees, and weather will affect your reception.

As for being on the wrong side of a mountain, you need to have a map anyway, and I belive a compass is essential - even with a GPS. Take out your compass and point it at the mountain top, if it is the wrong direction from your position based on your GPS coordinates, then your GPS is wrong. Belive me, this can happen, I have seen it.”

“I was in a car going west and in the middle of PA...when I looked at my GPS it indicated that i was over Lake Erie at a high altitude and going some ridiculous speed. No that your GPS is doing that, but it shows you how wrong they can be. I think it was a Gov test or something that caused it...or aliens.

You should rely on a map and compass more than your GPS. And use your GPS as additional confirmation as to your location. If you can create a waypoint and change the location t a specific location (ie. mountain peaks, stream confluences or whatever around you) and use them as reference to your location, the GPS display will give you a better reference as to where you are especially when comparing it to a map. KNow what I mean?”

“or acid.”

“I also have an Etrex and have yet to have any troubles with it at all. I've used it everywhere from mountains to fields. Although it did take longer to get a fix under heavy cover.
I agree with Budder about relying on your compass more than the GPS.”

“I would be very very upset if I had a GPS and it told me I was over Lake Erie if I wasn't. That disturbs me.

Question, though: SGT ROck, wouldn't reception have more to do with the unit? Ex., two radios get the same FM frequency, but a better brand will get clearer reception and perform better. Why wouldn't that be the same?”

“It has to do with two things: antennas and signal.

Signal you cannot control, the satalites send them out. No one gets a better signal sent to them because of brand.

Antennas rely on getting a clear signal from the satalite. Unless your GPS commes with a 50' mast that pokes above any cover, it is equally useless under cover as any other.

As for better brands radios, I have seen excellent radios get poor reception because they were attached improperly to an antenna, or had a very poor antenna (small and poorly located). I have also seen someone get excellent reception on a very crappy portable radio because they hooked it up to a very large and well placed antenna.

I have yet to see a personal GPS with an antenna that would give super reception, they all have those stubby ones. In the Army, we have these exterior antennas for our GPS systems, very powerfull covered dish type antenna, but get it under good cover it still will not recive.

Recently saw a survey GPS that had a similar antenna mounted on a mast for getting good reception, still haven't seen one for a handheld GPS.”

“I spend a lot of time using GPS units. I have three different brands, including an Etrex. I also have a magellan and a Lowrance. The Lowrance is by far the best. I can't really explain it, but when using all three units in the woods, the Lowrance will continue to stay locked on when both of the other units have lost their signal. I am still impressed with the etrex and what it will do for the money. It is a great unit. However, there is still no substitute for a good topo map and compass.”

“One other note. Sometimes the data from your GPS is wrong because you are using the wrong map datum. You must check the lower left of your map and see which datum is being used. In most cases of 7.5 minute maps from the USGS, the datum is NAD27. If your GPS is using some other datum, it can be off by a considerable distance.”