Dakota 20 Compass

[Swallows2]

Reading the forum I decided to get a Dakota 20. As the compass was well thought of. But using it today, it was useless. It took me near the cache but was then all over the place. Pointing in all different directions! I re-calibrated it but still the same. Am I doing something wrong or is it really that bad?

Bri

[+Gitchee-Gummee]

It took me near the cache but was then all over the place. Pointing in all different directions!

 

Simple, really.... When you near the cache, put the device away. It has done its job. It is designed to take you to the area of the cache. Not the cache proper. If you keep looking at the device, you are wasting your eyesight. Look for the cache or its hiding spot instead. If you keep looking at the GPSr, you'll probably never spot the cache.

 

Typically, you should expect it to get you within 6-10 meters of the cache. When the compass (pointer, really) starts jumping around, it is time to put it away. Recalibrating it does you no good, you cannot make it do something it is incapable of doing -- giving you the cache on a silver platter.

 

They all do it, no matter the make, type or model. Sure, upon occasion it can steer you directly TO the cache, but more often not.

Remember, you are hunting for a cache, not being led like a lamb.

 

The "pointing all over the place", jumping around, pointing here then there then over that way... these are questions asked repeatedly in these forums and the answer is (most) always the same.

[Swallows2]

It took me near the cache but was then all over the place. Pointing in all different directions!

 

Simple, really.... When you near the cache, put the device away. It has done its job. It is designed to take you to the area of the cache. Not the cache proper. If you keep looking at the device, you are wasting your eyesight. Look for the cache or its hiding spot instead. If you keep looking at the GPSr, you'll probably never spot the cache.

 

Typically, you should expect it to get you within 6-10 meters of the cache. When the compass (pointer, really) starts jumping around, it is time to put it away. Recalibrating it does you no good, you cannot make it do something it is incapable of doing -- giving you the cache on a silver platter.

 

They all do it, no matter the make, type or model. Sure, upon occasion it can steer you directly TO the cache, but more often not.

Remember, you are hunting for a cache, not being led like a lamb.

 

The "pointing all over the place", jumping around, pointing here then there then over that way... these are questions asked repeatedly in these forums and the answer is (most) always the same.

[Swallows2]

Thank you so much for the intelligent reply. I will do as you say. The only thing I can't understand is why it does it! I bought this as I thought it would take me to the area and still stay stable. But leaping about all over the place, I can't understand.

Best Regards

Bri

[+ecanderson]

+1. Once you're close enough to the cache, the device's accuracy and drift will eventually have you wandering the area.

 

However, there is a technique you can use that may improve your approach to the use of the compass.

 

Back away from ground zero about 30 feet. Holding your unit level, take a look at where the compass points. Now, move around ground zero in a wide arc. Keep watching where the compass is pointing. Eventually, you'll find that you've triangulated the position that your Dakota really believes belongs to the cache coordinates. Of course, there's still a lot of guesswork since you don't know how accurately or carefully the CO has taken his own readings when placing the cache.

 

Another example of using that technique that has been especially useful to me in the mountains here in Colorado and in downtown Denver...

 

I've had issues where a cache was placed up against against steep vertical wall or near a tall building. In those situations, your unit is shaded from at least 50% of the available sky, and reception can be pretty poor. At times, I've had good luck stepping back away from ground zero and taking a couple of readings with the compass at 30 to 40 feet out away from the wall/building in (again) an attempt to triangulate a position. If the CO was very careful to do some long averaging and the coordinates are actually good, and if you don't want to replicate that kind of exercise due to time, just backing away and getting a bit more clear sky can really help.

 

Over time, you and your compass will no doubt become friends, but you need to understand where and how it is best used. Once you reach a point about 30~40' from ground zero, take a moment to look at where it's pointing, and just count down the distance and ignore the arrow!

[+ecanderson]

You keep repeating your disdain for this feature, but don't seem to qualify your comments. Nothing points to the cache if you're practically standing on top of it. Did my examples above not help you understand why some of us find this tool very useful, especially when we can't keep moving quickly to cause the then useless 'GPS compass' to work at all?

Edited December 1, 2013 by ecanderson

[+Gitchee-Gummee]

The only thing I can't understand is why it does it!

 

Well, the why is a little obscure. First and foremost, it is a consumer-grade device. Commercial and/or military grade can be a bit better, but mostly then just at delivering the coordinates location -- not necessarily with the compass going "haywire" when it is too close to that location.

 

It is the directional pointer, not really the compass that you are looking at. It's trying to point you in the proper direction, but when you get within a certain distance from the coordinates, it has a difficult time deciding whether you are AT, YET APPROACHING or ALREADY BEYOND that point.

 

As an example... if you have a compass that could read only True North and you are standing at or really, really close to the North Pole, which way is it going to point?

I know, it is an absurd comparison, but there is a parallel to it.

[+ecanderson]

One thing that I would encourage all users to do is to include the current EPE as one of the items on the active screen. Knowing what the unit believes the horizontal error to be (in feet or meters) says a LOT about how far away you will need to be before the compass will remain reasonably accurate, and will also give you a very good idea of how wide your search area might need to be as you approach the cache. Again .. all assuming that the CO did a decent job with the coordinates to begin with. I don't favor using the geocaching dashboard only because of the information I can display on the compass screen instead.

 

Attached is a pretty gross example (74 feet EPE!!) but that number is very important when closing on on GZ with a compass, or even if you're NOT using a compass.

 

Well nuts ... forgot you can't upload images to this site (too cheap to supply the server space!). I'll try to add a link or two. Hope they come up properly. If not, I'll add another post.

 

Point being .. look at the information on the compass page, in particular, the 'GPS Accuracy' number. The difference in how one uses the compass, or just plain approaches a cache, should take that number into account.

 

[+ecanderson]

OK - try this silly thing again:

 

Nope... I've lost my embedded image mojo here entirely. Here are the links. It's the importance of the circled region on the compass view that I'm trying to point out.

 

http://www.mediafire...hing%20Page.jpg

http://www.mediafire...pass%20Page.jpg

[Swallows2]

Thank you so much to everybody. I now have an idea of what is happening. I thought that I had done something wrong or that my Dakota was faulty. I am full of confidence again now.

Bri

[39_Steps]

It's why I never bother with an electronic compass. Folks say their advantage is they 'always point to the cache' but, as you've discovered, they don't

Perhaps I am somewhere between 'never' and 'always' in my concern with recalibrating the voltage dependent electronic compass in gps devices. However, sussamb's 'never bother' comment did get me out into an open space for some simulated geocaching with and without the electronic (magnetic) compass enabled in my primary device, which is not a Garmin.

 

For someone old and sedentary (ahem), but somewhat device savvy, the electronic compass seems more likely to help than hinder when looking for a cache. However, I can see that a more active cacher on the run (faster than 2 mph?) might consider the electronic compass a nuisance.

[+ecanderson]

... recalibrating the voltage dependent electronic compass in gps devices. ...

That's been my one gripe with Garmin and their electronic compass (which I use to my advantage frequently). Why on earth isn't their compass chip using one of the internally regulated supplies? I got around this a few years back by using NiZn AA cells. Their discharge profile is pretty much dead flat. In other words, the voltage remains relatively constant over the entire duration of the discharge. Fresh, their voltage makes them look like a lithium cell. However, when you see them start to drop bars on the gas gauge, you have mere minutes to swap out for a new pair. So I calibrated once after about 5 minutes of use, and have never calibrated again as long as I have been using NiZn cells.

 

NiZn was being considered as a battery chemistry 100+ years ago, but the things wouldn't hold together in actual use back then. PowerGenix was the first to make them practical due to some clever manufacturing and process engineering. Unfortunately, PowerGenix never seems to have achieved any retail traction with their technology, and gave up on AA retail buyers. They're back to making automotive and other larger custom batteries now. After a couple of years of use, mine are starting to get a little tired, and when these go, I suppose that it will be another 100 years before anyone does anything with NiZn again (sigh). They were great little cells.