How close can you get?

[frogman911]

I have an old Magellan Sportrak and recently thought I would upgrade to newer technology. I ended up getting the Garmin Dakota 10 just because it was on sale locally and it did have some good reviews. Unfortunately it doesn't seem to be very accurate. I tried to find a cache and it had me about 70 feet off the first day. The next day it got me close enough to find it. A couple other cache's I could not find and it kept bouncing me around the spot within 30 feet or so. It seems slow to react to my movements. Actually not much better than my 8 year old Magellan, which I really didn't like either. The Garmin does have nicer features but not much better getting me there, which is why we have these things...

[hoosier guy]

Did cloud cover or vegitation play a part in the poor readings? Both of those will screw up your signal and you have to wait a little longer to get a good reading.

[+Jeep4two]

Make sure you have loaded the latest software/firmware updates for your Dakota. Use the Garmin Webupdater found here: http://www8.garmin.com/products/webupdater/howtoinstall.jsp

 

My unit (Oregon 400t) will get me within 20 feet assuming the cache is indeed where it is supposed to be. Keep trying and give it some time before you decide your unit isn't accurate enough. I've had caches be 80 feet (previous finders confirmed the bad coordinates) from where my GPSr said it should be as well as had my GPSr virtually read zero.

 

You'll find that some cachers have better coordinates than others as well. Some folks will drop their cache, turn on their GPSr and take a read as soon as they get a fix. Usually that's not very accurate.

 

Other cachers will choose their site, take an averaged reading then return several times over several different days to collect additional averaging samples before publishing. Those tend to be more accurate.

 

Regardless - expect a wide variance in the game.

[+Semper Questio]

A lot of things are going to make a difference. Nearby buildings, cliff faces, heavy tree cover, etc.

 

Also be sure you take the time to properly initialize your device mainly by turning it on on a clear day and sitting it out with a clear few of the sky and let it just sit there and think for a while. I do this periodically with mu 60CSx. I mean to only leave it 10-15 minutes, but I invariably forget it and leave it out there for a couple of hours!

 

As for how close you can get, there are a LOT of variables that come into play on both sides of the hide.

 

If your gizmo is having a good day it can put you very close (even sometimes right on) the entered coords. I find 10-15 ft. on mine to be about average, but it could easily be double that on any given day.

 

Then you have to deal with how good the coords are in the first place. This depends on the device the hider used, what the conditions were the day the hider placed the cache and took the coords, and how well they actually got the coords. Did they just do a "snap mark" on a heavily overcast day? Did they let their device sit there and average for 10-15 minutes on a clear day? Obviously, you won't know these things, but it does add to the potential perimeter error range.

 

So, assume they had a sorta bad day and their numbers are 30' off. Your gizmo says your error rate is 17'. You have a total error RADIUS of 45'. So when you get 40-50 ft. from GZ, you start thinking like a hider and look for places a cache as the one described could be hidden. Keep in mind I said "RADIUS". That gives you a total 90-100 ft. diameter search area.

 

Typically, I will start looking for a hiding spot about 50' away, looking ever-closer as I approach my gizmo's GZ. When I get as close to GZ as my device will take me I start there and start searching in an ever wider range. Sometimes I spot the cache or the hiding spot as I'm approaching, other times, as I'm working my way out from center. You just never know.

 

Hope all this helps a little.

 

Happy hunting!

[frogman911]

Thanks for the info! I guess technology still hasn't advanced as far as I thought. When they advertise within feet, I wasnt expecting 50 - 80 feet! It's wierd how it gives you different locations with the same coordinates. My last one I used for finding shipwrecks, so I never knew if I was on the spot until I geared up and dove in. When you're off, it's a little inconvenient, especially when your going down 130 feet to find nothing in low vis. I'll take into consideration clouds as well. I guess I'll get used to it.

[+StarBrand]

Don't worry about clouds - it will not affect the readings hardly at all.

 

http://gpsinformation.net/gpsclouds.htm

[+Gitchee-Gummee]

Thanks for the info! I guess technology still hasn't advanced as far as I thought. When they advertise within feet, I wasnt expecting 50 - 80 feet! It's wierd how it gives you different locations with the same coordinates. My last one I used for finding shipwrecks, so I never knew if I was on the spot until I geared up and dove in. When you're off, it's a little inconvenient, especially when your going down 130 feet to find nothing in low vis. I'll take into consideration clouds as well. I guess I'll get used to it.

No commercial-grade GPSr can guarantee you spot-on accuracy. Most cachers get to 20 - 30 ft and start looking for the cache, not at the GPSr.

Two things (plus other variables) come into play here.

1. A cache is placed (supposedly) by using GPSr coords -- and we accept about a 20 ft. variance as the norm;

2. A cache is found (supposedly) by using a GPSr -- and we accept about a 20 ft. variance as the norm;

Other unknown/unseen aberrations can affect both/either of those readings...

 

Can you see where I am going with this? You could expect a geocache to be within a 20 ft. circle, BUT that circle can easily extend to 40 ft. or more.

 

Your 30 ft. "bouncing circle" can be expected because as you close in on the "spot" (aka Ground Zero), your GPSr is reading signals from moving satellites. That's the time to start paying attention to the hunt, and not the GPSr. Let your eyes and brain take over from that spot and start looking for the hiding place.

 

EDIT: As far as advertising goes... But wait, there's more! Order in the next 10 min....

Edited May 20, 2010 by Gitchee-Gummee

[+NgaiHill]

I have the Dakota 10 and find it is a great, accurate wee device. Cloud cover does not affect it much and I have even had it put me at 0 metres to the cache. I recently found a cache that the CO said was 4m away from the coords. With my Dakota held next to the cache container in situ it was reading 4m away, so spot on!

Here is a couple of things you can try if you think it is off course;

 

1. Tell it to recalculate off road then walk around in a 4-5m circle, give a minute or two to recalculate.

2. Switch back to recalculate on road and repeat the circle.

3. Go to Where to? and stop navigation. Walk away from the cache site 10-20m, call up the cache info again and hit the go button. Walk around in despairing circles again and again give it time to recalculate.

Hasn't failed me yet! Good luck

[+briansnat]

Thanks for the info! I guess technology still hasn't advanced as far as I thought. When they advertise within feet, I wasnt expecting 50 - 80 feet! It's wierd how it gives you different locations with the same coordinates. My last one I used for finding shipwrecks, so I never knew if I was on the spot until I geared up and dove in. When you're off, it's a little inconvenient, especially when your going down 130 feet to find nothing in low vis. I'll take into consideration clouds as well. I guess I'll get used to it.

 

50-80 feet of is a bit much. If you are consistently getting that then you might have a defective unit. You can usually expect to find the cache 10-30 feet from where your GPS says it is, though 40+ isn't unheard of.

[+StarBrand]

I have the Dakota 10 and find it is a great, accurate wee device. Cloud cover does not affect it much...

 

Reiterate - clouds have virtually no affect on any GPS receiver. See above.

[hoosier guy]

I see the data, but experience tells me clouds do make a difference. May just be my unit I am willing to say.

[+journey4truth]

I've been curious about this myself. I'm not using a traditional GPS receiver, and while traveling around in the Adirondacks in New York, the accuracy was usually off by 20-30 feet. It was my understanding that GPS receivers with better antennas can regularly bring you as close to 8-10 feet unless the conditions are pretty bad.

 

I had one scenario where I had to find a micro, and I could only get within 30 feet, with no hint. I was in the middle of a field. Seriously? And I get no hint at all? It was maddening since 30 square feet was a lot of ground to cover for a micro, but I blamed my GPS for not being accurate enough to make a find easier.