Conquering Tree Cover

January 4, 2004

Anyone have tips to share on improving GPS success in heavily wooded areas? GPSr units that work well (or poorly)? Techniques that have been helpful? Walking vs. standing still? WAAS on or off? Clicking heels three times?

Edited January 4, 2004 by Karma Hunter

24.7k · January 4, 2004

I use a variation of triangulation.

There will be places you get reception. Use that to project a line. Walk around until you find another location with reception and use that spot to project another line. Do a third and that line should cross the other two you made a note of. Where they cross should be where you should look.

January 4, 2004

Anyone have tips to share on improving GPS success in heavily wooded areas? GPSr units that work well (or poorly)? Techniques that have been helpful? Walking vs. standing still? WAAS on or off? Clicking heels three times?

Buy a Magellan... :huh:

No GPSr will work 100% under a thick tree canopy. Yes moving around will help as that's the only way you will get updated data anyway. WAAS on or off (why would you turn it off anyway) makes no difference. If you get a WAAS signal more power to you. If not it won't matter. Get as much signal as you can and stand still for a bit for the averaging to work itself out. Don't forget that even out in the open if you are within 30 feet your not lost. You just have to look a bit harder..

January 4, 2004

Which GPS unit are you currently using?

I first had a Garmin (forget the model #) in 1997 that I was disappointed in when using under tree cover. I got rid of it soon for that very reason. This past fall I bought new Garmin Etrex Legend and I am amazed at the improvement in reception. Tree cover doesn't seem to be an issue, also I can often receive less than 25' accuracy inside the house.

3.8k · January 4, 2004

Anyone have tips to share on improving GPS success in heavily wooded areas? GPSr units that work well (or poorly)? Techniques that have been helpful? Walking vs. standing still? WAAS on or off? Clicking heels three times?

Some light reading for you :huh: Comparison of GPS Receivers Under a Forest Canopy

1.4k · January 4, 2004

From the various WAAS discussions, you probably should turn it off as it may create more problems then it solves in marginal conditions.

What units work well in the forest has long been debated, but the biggest improvement is likely to be when you use an external antenna.

January 4, 2004

From the various WAAS discussions, you probably should turn it off as it may create more problems then it solves in marginal conditions.
What units work well in the forest has long been debated, but the biggest improvement is likely to be when you use an external antenna.

I will never try to be an expert on WAAS. Reason is I am going to go by what my experience is and use that. I can't turn off WAAS on my Magellan. I wouldn't if I could. My GPSr will use the WAAS signals when available. And not if they aren't. As I have said in my previous post.......I have plenty of finds and hides with and without WAAS coords. I've NEVER had a problem with not being right on target anyplace. I've had WAAS during tree cover while another dasher was hunting for a signal. He was using an older unit (brand doesn't matter here). The difference was the antenna on the unit and both of us have internal.

January 4, 2004

I don't know what unit you have but I got a Titan III external antenna I use and it does a perfect job under all conditions hiking though out the White Mountains year round. It has more sensitiveity than stock 76S antenna and uses sat's better. Idid a lot of research about them and they do and will help.

I have mine located on top of my pack and record every hike from start to finish. Useually up to 10 hours. The only time I break in reception is if I flip top back too long. While getting lunch,etc.

Before the extennal antenna, no matter what I did I would lose reception. Same with the old GPS 48 I had.

Capt.

January 4, 2004

Buy a Magellan...

Why would he do that? If you cannot do this

I can't turn off WAAS on my Magellan.

Actually, you can turn it off. But there is a specific sequence of keystrokes that I cannot remember to get to the hidden menus to turn it off. I think it was hidden sub menu #3.

Great case in point as to why I do not own a Magellen. Why would you need to know a secret hidden code to turn off your own WAAS reception and extend your battery life. I guess that they figure Magellen owners are not to be trusted to make such hard decisions as "WAAS on or off?"

The WAAS signal is really only useful when you are in within sight of the two (one east coast, one west coast, only #'s 33 and above) satellites. It does not matter if it is tree cover or highrises blocking your reception, you either get it or you don't.

When you are navagating where you really need the WAAS accuracy, such as aviation or marine navigation, you can see and recieve the WAAS signal as there are hardly ever trees overhead blocking reception when I am in an airplane or a boat....... if there were there would be bigger problems than the GPS accuracy.

If you feel you NEED WAAS all the time, then get a remote antenna, mount it on a pole and raise it ABOVE the tree canopy like the surveyors do. Of course you need a unit with extrernal antenna capabilities and pretty darn long pole for some areas......

1.2k · January 4, 2004

I personally used to use a Garmin GPS III+, but had major problems with that once the tree cover got to even moderate amounts. I have a Rino 120 now and, while the reception is definitely improved, I'll still have occasional problems with thick tree cover. What I tend to do in those cases is go to a spot where the accuracy seems to be greatest, get a bearing and distance off of the GPSr, and just start walking in that direction. 9 times out of 10, that'll put me right on target.

I have a Meridian and GlobalSat Bluetooth GPSr as well, but haven't used either of those in the field (yet). Those were bought mainly for development testing and haven't yet found themselves in my caching pack.

1.2k · January 4, 2004

Actually, you can turn it off. But there is a specific sequence of keystrokes that I cannot remember to get to the hidden menus to turn it off. I think it was hidden sub menu #3.

This is it for Meridians (not sure about other units)...

Menu, Right, Left, Right, Left, 03 (up 3 times), Enter

After that, it's Enter to toggle WAAS on and off, and Esc twice to get back to where you were.

January 5, 2004

Use an external antenna, it makes a significant difference. WAAS on/off DOES matter. Turn it off. Currently, it's only meant to be used under IDEAL conditions, i.e. not under tree cover. It increases processing time considerably and can cause greater error when used under less than IDEAL conditions. For consumer grade handhelds, it's just another marketing ploy, for the most part. More info on this available here.

Poindexter

January 5, 2004

Great case in point as to why I do not own a Magellen. Why would you need to know a secret hidden code to turn off your own WAAS reception and extend your battery life. I guess that they figure Magellen owners are not to be trusted to make such hard decisions as "WAAS on or off?"

First of all it's MagellAn.

Second of all Yes I know how to turn off the WAAS on a model that I don't own. Third of all the reason they don't make it that easy to turn off is BECAUSE THEY KNOW YOU WILL WANT IT ON.

Fourth, how can something that's not being used (absence of WAAS sat) use more battery?

Fifth, this kind of banter can go on until the WAAS sats are dead or so much improved that the subject will no longer be viable.

Have a nice day.

January 5, 2004

Which GPS unit are you currently using?

Currently we have a Magellan Sportrak Map, which works great (although there is no leaf cover this time of year). It gets reception indoors, even with blinds down. It gets very good reception lying in the front seat of the car, although it's supposed to receive better when held upright. Seems to even get reception carried in a coat pocket. However last summer my wife borrowed a Garmin Vista that got good reception in the open, but was off by over 200 feet in heavy tree cover. We don't have the Vista now, so I can't do a good comparison of the two.

Edited January 5, 2004 by Karma Hunter

1.3k · January 5, 2004

I have a sportrak, and it uses the same method to turn off WAAS as the Meridians do. Also, I always leave the was on, but as far i can see, it doesnt use WAAS all the time. I like that feature because i dont have to think about whether i should turn it off or not. If i will get WAAS, then i do, if i wont recieve it, then it uses the standard satelites. I like that feature also because in times when i didnt think there would be any way that i could be recieveing WAAS, i was, and a pretty strong signal also. From my experience of a Vista, and my sportrak, the sportrak does seem to hold a signal better in the car, under trees, etc. I know that Magellans will sometimes "fake" the signal, so it seems like you are getting reception when you are not, so i have the alarm on that beeps when the signal goes out, and even then, it seems to hold a signal stronger than the Vistas.

Before this turns into a war, here is my disclaimer.

I HAVE NO INTENTION OF STARTING A BRAND WAR. I DO NOT NECESSARILY THINK THAT MAGELLANS ARE BETTER THAN GARMINS, I WAS JUST STATING MY EXPERIENCE. THATS ALL. THANK YOU.

There ya go

January 5, 2004

Yes moving around will help as that's the only way you will get updated data anyway.

Not sure I understand how this works. Does my GPSr stop gathering info when I stand still? I thought it was still receiving, but that being in motion gave it more "comparative" (for lack of a better explanation) information to process. I have noticed that as I'm walking toward a waypoint I can get down to less than 10 feet away, but that if I then stand still, the reading sometimes climbs back up to 20 or more feet. I then walk again and find a "better" location where the sub-10 distance stays. I haven't noticed my EPE in these situations, but will pay attention to it in the future. I guess I've diverged a little from the original intention of this thread, but if anyone has a quick explanation of still-vs.-walking readings I'd like to know more. Thanks.

January 5, 2004

I HAVE NO INTENTION OF STARTING A BRAND WAR. I DO NOT NECESSARILY THINK THAT MAGELLANS ARE BETTER THAN GARMINS, I WAS JUST STATING MY EXPERIENCE. THATS ALL. THANK YOU.
There ya go

Agree 100%

1.3k · January 5, 2004

Just to add something else that i noticed the other day. I turned my Sportrac Map on inside my house and i couldnt believe when it started to pick up satelites and then got a lock. I sat and watched the screen and it got such a strong lock, it amazed me. I wandered around my house and the signal still kept. I thought that was pretty cool considering that the Vista i was using before (and this is not a bash on Garmin ) would lose its lock inside the car.

1.4k · January 5, 2004

I thought that was pretty cool considering that the Vista i was using before (and this is not a bash on Garmin ) would lose its lock inside the car.

It all depends on the house and car. A house with a wooden roof doesn't do much to block the GPS signal. But a metal car with the right type of tint (or wrong type of tint depending on how you look at it) will severely kill the GPS signal.

I think your example has more to do with difference of location then difference in GPS.

Edited January 5, 2004 by GeckoGeek

January 5, 2004

It all depends on the house and car. A house with a wooden roof doesn't do much to block the GPS signal. But a metal car with the right type of tint (or wrong type of tint depending on how you look at it) will severely kill the GPS signal.

I would agree with metal and tint being strong signal blockers, but it seems that wood pretty effective too. After all, isn't a wood house essentially just a really solid form of tree/leaf cover?

24.7k · January 5, 2004

It all depends on the house and car. A house with a wooden roof doesn't do much to block the GPS signal. But a metal car with the right type of tint (or wrong type of tint depending on how you look at it) will severely kill the GPS signal.

I would agree with metal and tint being strong signal blockers, but it seems that wood pretty effective too. After all, isn't a wood house essentially just a really solid form of tree/leaf cover?

It's the water in the trees more so than the wood that block signals. It's also why your own body blocks signals if you keep the GPS too close or are are between the GPS and the critical satalite it's tracking.

The Vista has a patch anteana and the Sport Track Pro Quad Helix. The GPS V (and probably the III) have Quad Helix. Both will perform slightly better due to the better antanea than the Patch. The patch antenea does have advantages that come into play here in Idaho where I'm about as likely to be in a forest as near a canyon wall.

WAAS does work, but at least on the Garmins it noticably slows down the refresh rate. This can be an annoyance depending on how you use your GPS. I keep WAAS off. Losing 10' of accuracy is no big deal in geocaching. It also extends battery life in the Garmins.

I've been told that on or ff in the Magellans makes no difference in battery life. I haven't heard anything about refresh rate. I do know the Sport Track Pro's refresh rate can cause issues on the rubber band map page with too much detail in the background map turned on.

1.4k · January 5, 2004

After all, isn't a wood house essentially just a really solid form of tree/leaf cover?

Dead wood has a lot less moisture then a live tree. Moisture is the real enemy, trees are just a way of holding it over you.

January 6, 2004

Dead wood has a lot less moisture then a live tree. Moisture is the real enemy, trees are just a way of holding it over you.

So does that mean the petrified forest wouldn't be a problem?

1.4k · January 6, 2004

So does that mean the petrified forest wouldn't be a problem?

No worse then inside a wooden house - assuming there's no snow on the branches. At least that's my guess.

January 6, 2004

.
Fourth, how can something that's not being used (absence of WAAS sat) use more battery?

The unit will keep trying to find the sat and lock on and will use extra battery power to try so from what I've read.

Better off shutting it down. Also like I said earlier I use a external antenna from Titan III for my 76S and never lose fix and always find good accuracy even down in revines. But that's when I'm hiking. were not usually in a reveine all day and the WAAS correction is still applied for a while as long as at some point earlier you had a good lock onto it.

Hope this helped.

Edited January 6, 2004 by capt caper

1.4k · January 6, 2004

.
Fourth, how can something that's not being used (absence of WAAS sat) use more battery?

As best as I can determine from the technical side, having WAAS on prevents you from using battery saver. But having battery saver on can create other issues, so you may not be using it anyway.

January 6, 2004

I don't think my 76S has battery saver at all that I can find anywhere. I think originaly it was suppose to have it but the upgrades did away with it?

Maybe someone will prove me wrong.

Jim

January 6, 2004

First of all it's MagellAn.

Ya, whatever. You say toe-mayto, I say toe-ma-toe...., make ONE SMALL spelling mistake......

I can't turn off WAAS on my Magellan. I wouldn't if I could.

Second of all Yes I know how to turn off the WAAS on a model that I don't own

What? Are they all different? Can you turn it off or not? Or is it just the Sport trac units that have this option?

Fourth, how can something that's not being used (absence of WAAS sat) use more battery?

If it is busy searching for a WAAS Signal, it would be using more power than if the WAAS circuit was turned off.

Conquering Tree Cover

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