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GPS for under the trees
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Daniel Schmidt
(dschmidt) - F
GPS for under the trees on 03/24/2006 13:23:15 MST Print View

Any recommendations for a GPS receiver that would have reliable reception under the trees?
Some of the ones reviewed here at BPL look great for more clear alpine conditions, but if I am going to pay the money I'd rather it work if I get lost wandering aimlessly in the woods.

Daniel Schmidt
(dschmidt) - F
and is lightweight of course on 03/24/2006 13:46:44 MST Print View

or at least reasonably lightweight, say 5oz max. Or is it better/possible to add an antenna extenstion to the something like the Garmin Geko 301?

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: GPS for under the trees on 03/24/2006 15:05:32 MST Print View

Check out the recently upgraded etrex "Cx" models (there are three). They use a new processor chip that has lower power consumption and greater sensitivity--even indoors from what I've read so reception underneath a forest canopy should be considerably improved.

IIRC they're a little over 5 oz w/ batteries. They now take microSD cards and use USB interface.

Generally speaking, even the current crop of receivers can track your position under tree cover if it's running at the time you enter the woods. They have a much harder time acquiring a signal if you switch them on once in the woods.

Edited by halfturbo on 03/24/2006 15:07:40 MST.

Mike Barney
(eaglemb) - F

Locale: AZ, the Great Southwest!
Re: GPS for under the trees on 03/24/2006 18:43:05 MST Print View

The state of the art for sensitivity is the SIRF III GPS chip set, which powers the new generation of the ultrasensitive units.

One of those is the Garmin GPSMap 76CSX. I just got one, it's 7.6 oz, not cheap, but works under trees, in houses. But most amazing, it did the very initial fix in 30 seconds, very nice display, and waterproof.

MikeB

Douglas Frick
(Otter) - MLife

Locale: Wyoming
Re: GPS for under the trees on 03/25/2006 12:09:52 MST Print View

> Any recommendations for a GPS receiver that would have reliable reception under the trees?


Another recommendation for any of the new Garmin 60 or 76 series. I have a GPSmap 60C and I've never had a problem getting a fix except in heavy jungle. An external Gilsson antenna gets a fix anywhere.

My eTrex Legend had problems getting a fix under medium and heavy cover, and that's when I needed it the most. Not recommended. (No external antenna connector, either.)

Edited by Otter on 03/25/2006 12:10:24 MST.

Brian James
(bjamesd) - F

Locale: South Coast of BC
Garmin 60CSx vs. 76 CSx on 03/27/2006 09:55:07 MST Print View

Interesting; these two units have *identical* feature lists with the exception of one line: on the 76CSx it states "Unit floats when dropped in the water."

Is that the only difference? A housing that contains flotation?

Jeff Black
(thehikingdude) - F
Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 11:38:11 MST Print View

The main difference between the two is the placement of the buttons on the device. The 60CSx is more trail friendly in my opinion since the buttons are below the display, also I feel the 60CSx is more durable on the trail as well.

I just got one about 2 weeks ago and love it. On my first trip with it over the weekend I never lost the signal, under heavy tree cover while in a canyon. It's an amazing device.

-The Hiking Dude

Douglas Frick
(Otter) - MLife

Locale: Wyoming
Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 13:01:36 MST Print View

> Is that the only difference? A housing that contains flotation?


The 76 series is targeted toward sailors. It used to have (still does?) a database of nautical points, and it used to have more memory than was available in the 60 series. The housing is a bit bigger, which is why it floats. The 60 series is meant for land use, which is why it fits in the hand better and has grippy sides.


The 60 series has a thin rubber web on the antenna with a hole in it, the perfect size for a micro-biner or zip-tie. Don't do it. It's not very strong, and if it breaks you can lose the GPS (fortunately, I also had the leash clipped into the micro-biner).

Edited by Otter on 03/27/2006 13:11:47 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 15:51:22 MST Print View

Is there a leash attachement on both of these units? Please explain how it works or post a picture of the leash attachement on the 60 you have.

Sheldon McElhiney
(mcelhineysc) - MLife

Locale: Pacific Northwest
Re: Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 21:39:33 MST Print View

I think the 76 is easier for data entry/manipulation. It's simple to mash buttons using just a thumb without obscuring the screen while still maintain a good grip on the unit with one hand. The reception is significantly improved over older versions and the mapping can be quite functional depending on your intended use. After experimenting with the 76CSx for about a week, I still prefer the Geko 301; I just wish it had a neon colored case.

Douglas Frick
(Otter) - MLife

Locale: Wyoming
Re: Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 21:45:19 MST Print View

>Is there a leash attachement on both of these units?


I'm not sure if there is an attachment on the 76-series; my friend who uses one keeps his in a clip-holster. Here is a picture of the back of the GPSmap 60C. The post and black clip weigh 0.7 oz. The strap is 11" long. Instead of using the strap, a 3/32" zip-tie will fit through the leash slot. (I prefer the strap because I can keep it clipped close and also still keep it leashed when unclipped.) You can see the broken piece by the antenna where I used to have it clipped.



The smaller of the two ports visible on the back is for an external antenna. The Gilsson antenna works great and is much cheaper than the Garmin antenna. Be sure to get the 90-degree plug so the cable doesn't stick out of the back. You don't need an external antenna unless you're going to rely on the GPS in heavy jungle, but the Gilsson is great for mapping trails.


Edit: Gilsson Amplified GPS Antenna with 90 degree MCX connector, 3-foot cable: 2.8 oz. Cut a 2"x2" piece of thin steel to match (0.3 oz), and you can use the built-in magnets to secure it to a hat. The steel also acts as a ground plane for the antenna. You could save almost an ounce by removing the magnets, but be sure you've figured out how you're going to secure it first.

<http://www.gilsson.com/garmin_gps/antennas/mcx.htm>

Edited by Otter on 03/27/2006 23:07:21 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Garmin 60CSx vs. 76 CSx on 03/27/2006 22:41:03 MST Print View

Douglas,

Thanks for the explanation and picture.