Help with DUSI

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Re: Help with DUSI

Postby Squeamish » Apr 30, 2011 3:53 pm

I recently got a DUSI for some underground surveying work. Accuracy is very important to this project. I followed the calibration directions in the "About" menus, but the unit still believes north (0º) is in the southeasterly direction. Immediately after calibration, the unit read 160º when pointed due north, 225º when pointed due east, 50º when pointed due south, and 80º when pointed due west. Does anybody have any idea what could be going on? These values are from indoors so I'm guessing the inconsistencies between them (aka not 90º) are caused by magnetic distortion, so that should be OK when I'm underground. I think the only real issue is that it thinks north is southeast.
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Re: Help with DUSI

Postby WVCaver2011 » May 2, 2011 11:42 am

The DUSI is very sensitive to magnetic distortions. I have to calibrate it in cave all the time because I cant find a place outside that has no magnetic anomalies. As long as you calibrate it in cave you should be fine. Every time you vary 50-100 feet in elevation you will need to recalibrate it. At least that's what i've figured out. It seems to work, I get good loop closures just about every time. If you find rust stains on the walls you better pull out your Suuntos.
There's nothing that makes me more excited than finding a place underground that no one has ever seen or been in!

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Re: Help with DUSI

Postby Squeamish » May 2, 2011 9:44 pm

Thanks! Do you think the issue with the unit thinking north is southeast is the type of error you'd expect from magnetic distortion? It just strikes me as odd given how consistently it's off. If my recollection is correct, it thought north was southeast both after the first calibration attempt, and after I cleared out the first and attempted to calibrate it a second time. The consistency makes me feel there's more wrong with the unit than just magnetic distortion, but I defer to your expertise.
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Re: Help with DUSI

Postby WVCaver2011 » May 3, 2011 8:29 am

Squeamish wrote:Thanks! Do you think the issue with the unit thinking north is southeast is the type of error you'd expect from magnetic distortion? It just strikes me as odd given how consistently it's off. If my recollection is correct, it thought north was southeast both after the first calibration attempt, and after I cleared out the first and attempted to calibrate it a second time. The consistency makes me feel there's more wrong with the unit than just magnetic distortion, but I defer to your expertise.


Anything can happen in magnetic anomalies. The only real way to test it out and make sure your instrument is working properly is to go underground and see if it aligns itself with the correct directions. It takes a while to get used to the DUSI and it's sensitivity. When it's in cave the DUSI is pretty good in most cases but make sure you bring your Suuntos along with you.

I've had issues with my DUSI not wanting to turn on, or turning on only to show a blank lite up screen. It was really frustrating! However, more times than not, I would end up pulling out my Suuntos and taking a shot or two and the DUSI would turn back on the proper way. The DistoX will be superior to the DUSI. When it comes out, i'm selling it and getting a DistoX.
There's nothing that makes me more excited than finding a place underground that no one has ever seen or been in!

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Re: Help with DUSI

Postby Squeamish » May 5, 2011 3:11 pm

OK, thanks for the advice! I'll try it underground and see if it works there.
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