I crapped out on two mountain caches two weekends in a row because I lost GPS under the canopy. I think the problem can be solved if there is a nearby spot where coverage can be acquired and a compass bearing with an accurate distance to the point will get you where you need to be. I have a Suunto sighting compass I use professionally ($+-$100) but my pacing just isn’t close enough in rough terrain. For the distance, I bought a Bushnell Laser Rangefinder Pro which bounces an infrared beam off of an object and gives a distance. It is rated at 800 yards for a good reflective surface and 450 yards for a tree or rock. The accuracy is +- 1 yard. I checked that out on some known distances and it seemed to be as specified. I first ran a closed circuit and checked the misclosure. Those in orienteering will know what I’m talking about. That also checked out. The next check was on a mundane box in the park cache where I could get in the open and the cache was under the canopy 75 yards in. I got a good gps reading with the accuracy factor at 15 or so feet, waas enabled, and 6 satellites visible. I sighted the closest tree to the calculated bearing and took a distance. I needed to go 3 more yards beyond the tree and a couple more yards to the right. Using this I walked straight to the cache. I stuck my hiking staff in the ground and signed in and then observed the gps. It was giving me multiple readings, some as much as 60 feet away and some in a swamp! This a low end digital ranging device. I costs around $200 at Ben Meadows and the same at Sports Authority, but I got mine at the local Wallyworld gun department for $180. I wish it had an automatic slope distance reduction feature for steep slopes and the more expensive units will let you switch back and forth between meters, yards, and feet. I will keep you posted on my further trials with this device. I would not recommend buying one of these now if you think it is a plug and play, but if you are willing to do a few little simple calculations and understand its limitations, I do recommend on checking it out a little further.

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Originally posted by nasty george:
I crapped out on two mountain caches two weekends in a row because I lost GPS under the canopy.... This a low end digital ranging device.

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Huh? Low end? I understand the theory, but ...
Glad I'm just a 'desk jockey".

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... This a low end digital ranging device.

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What is a low end digital ranging device? The compass? The Bushnell Rangefinder? The GPSr?

For the distance, I bought a Bushnell Laser Rangefinder Pro which bounces an infrared beam off of an object and gives a distance.

You may still have an accuracy problem if you are at a very different elevation than the point you are ranging. I think that the GPS assumes the same altitude when computing distance to a waypoint, and if so, you would need to measure the angle from horizontal and do some trig to work out the right position. But maybe a few simple factors, for say 30°, 45°, and 60° would be enough to get close. Any comments?

CharlieP

You may still have an accuracy problem if you are at a very different elevation than the point you are ranging.

Yes. That is what I was talking about with the automatic slope reduction feature with the more expensive units. For example, say you are going up a very steep slope of about 10 per-cent and you measure a slope distance of 1000 feet. cos(arctan .1) x 1000=995 feet or 5 feet of difference. That is well within the limits of your handheld gps. Some military compasses also have a clinometer built in which could be used. I have a clinometer, but I will probably keep in in my pack for most hunts. As far as deviating from the horizontal azimuth, that brings you back to another of my statements regarding orienteering. This like any other measuring device requires some knowledge of what you are doing or it just ain't goin to help you. I will be using the rangefinder in my work as a professional land surveyor and will use it on recon surveys which are just sophisticated geocaches where you are looking for corner monuments. I also have programs in my calculator and in my palm pilot that do the number crunching.I would not advise anyone to buy one of these things unless they can use it in their noraml work and it is DEDUCTABLE. I would be happy to give a quick demom at a meeting sometime.
gw

I don't think one of these items will be a part of my caching gear anytime soon.

SporTrak $120
PPC $200
Misc Software $40
Premium membership $30
Cache loot $who knows at this point?

There's no way that I'll be able to justify another $200 expense for this "cheap" hobby.

It may take me a while to find them, but I'll have to stick to the standard way of hunting the caches.

- Mark (S-4-C)

Alas, when all is said and done, the cache is no closer to where the fanciest equipment says it is than the hider was when he took the coordinates with his cheap Garmin.