SAP vs DistoX

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SAP vs DistoX

Postby JSDunham » Sep 21, 2010 2:18 pm

I'm seriously looking at getting one of these for surveying here in the northeast--with the caves mostly small, tight, contortionist nightmares filled with mud, setting reasonable survey stations that allow one to get behind a suunto is difficult, and many short shots lengthen the time needed for an accurate survey. It seems like in reading about the SAP and DistoX that these tools would be godsends for surveys in tight passage where many short shots are needed. But how effective are they and how do they compare? In particular, I'm curious about how people using either or both of these feel about ease of use, reliability, water and dirt resistance, ease of calibration, accuracy of calibration, price tag comparison, etc. Any advice is appreciated!
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Re: SAP vs DistoX

Postby NZcaver » Sep 21, 2010 3:38 pm

John - if you haven't already searched the forum, check out this topic.
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Re: SAP vs DistoX

Postby wyandottecaver » Sep 21, 2010 4:02 pm

we have used both in the blowing hole system. The SAP seemed far far superior. The disto had trouble getting enough reflectiveness for readings. Then again we were in pretty dark passage.
I'm not scared of the dark, it's the things IN the dark that make me nervous. :)
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Re: SAP vs DistoX

Postby JSDunham » Sep 21, 2010 4:04 pm

NZcaver wrote:John - if you haven't already searched the forum, check out this topic.


I did see that one, thanks--I was mostly interested in side-by-side comparisons. Thanks, though.
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Re: SAP vs DistoX

Postby LWB » Sep 23, 2010 9:42 pm

Here is an old comparison chart. Perhaps some people have gotten good Pony data, but I haven't (by good I mean Foresights and Backsights that match within a reasonable limit. And even the Disto X - with a fresh calibration - does not always produce FS/BS errors of a degree or less. (But the next time the same Disto X is calibrated it may produce FS/BS errors within a degree). However, the Disto X rarely exceeds a 2 degree FS/BS errors (with a fresh calibration). I can't say that for the Pony. 8 degrees has not be uncommon in my experience.

Image

This chart is a comparison to Theodolite data with a plot of the Az and El errors. Some of the Pony data is off the scale.

The DUSI with the Beta software did well, but the DUSI v2 has not lived up to that promise (at least in my testing).

I'm not comfortable recommending anything other than the Disto X at this point. And all indications I have is that they need calibrated (and I have worked with 4 of them) at least once a month. The fact that the Disto X is first a Disto has some disadvantages to the DUSI and Pony. Unless Phil has improved the algorithm the Pony uses (like going to the Disto X / DUSI method) I think it will be limited. And Unless Sean sorts out what is wrong with the DUSIv2 software, it is also limited.

I like the Disto X - but it can be frustrating at times. I have gotten what appears to be a good (or even great) calibration (based on the calibration output), produce a tight grouping in a plot like above and yet fail the compass test course basic FS/BS test. One day I calibrated 4 Disto Xs and only one passed the test. Very annoying.

I recently tried demagnetizing batteries as one poster here claimed the cause of Disto X's going out of calibration was dominated by change in the batteries magnetic properties as they discharge - and if you demagnetized before each trip you could avoid a recalibration. I used the DUSI gaussmeter to check the field to verify the batteries were demagnetized. I was using a commercial demagnetizer and found that quite often it took a very large number of attempts to actually get some batteries demagnetized (while some only took one try). I was using lithium anyway because of they don't change as much as they discharge. The original advocate of demagnetizing the batteries didn't say how he verified that his batteries really were demagnetized. He was using regular batteries, not the lithium ones, so maybe his batteries were easier to demagnetize. I haven't had a chance to get the data to prove / or disprove this theory.
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Re: SAP vs DistoX

Postby LukeM » Sep 24, 2010 8:19 am

http://www.forums.caves.org/viewtopic.php?f=26&t=7478

The above topic may be useful as well. This particular person seems to have gotten accurate readings using the SAP.
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Re: SAP vs DistoX

Postby JSDunham » Sep 25, 2010 10:14 pm

That's all very helpful, thanks.
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Re: SAP vs DistoX

Postby lleblanc » Sep 27, 2010 12:30 pm

Hi,

I never used a SAP other than for implementing Bluetooth communication with it in Auriga, but I really can't complain about the DistoX. I was in Lechuguilla last May on a loop-fixing trip. Some loops had previously been surveyed (by other teams who shall remain unnamed) with closure errors as bad as 17%. Our two teams each used a pair of DistoX. We had set two test stations near camp and we checked DistoX calibration every morning. If a pair of DistoX didn't agree within a degree, we would recalibrate both. When surveying, measurements were repeated until foresight and backsight azimuth and slope agreed within a degree, and distance within two inches. The closure error of re-surveyed loops is now down to 0.4% !
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Re: SAP vs DistoX

Postby lleblanc » Oct 13, 2010 5:09 pm

Even better: we just redid the line plot of the river and fossil passages of the Cueva del Agua in the gypsum karst of Sorbas in Southern Spain. We then joined the two entrances at each end of the cave by a surface survey we had to do at night in order to see the laser dot (invisible under the desert sun). With 2 DistoX and backsisghts, and even with some surface shots of up to 55 metets, we reached a 0.14% (2.84 m) closure error over a 1968-m loop made up of 223 survey shots! Can't complain :)
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Re: SAP vs DistoX

Postby WVCaver2011 » Dec 24, 2010 8:09 am

Well,

After reading these posts i'm pretty determined to say that I would rather own a DistoX. It seems to be more accurate and less costly. However according to this site http://paperless.bheeb.ch/ the company thats currently making the upgrade kits are currently not making them due to some of the key parts not being manufactured any longer. Does anyone know where I could get one of these upgrade kits used but in good working condition if I buy the Disto A3 to put it in? DistoX just seems so much better overall. I figure if one of the "Key parts" broke there would be no further use of the DistoX correct? Has anyone been able to reproduce these "Key parts" besides the company that makes the upgrade kit? :shrug:
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: SAP vs DistoX

Postby Martin Sluka » Dec 24, 2010 10:01 am

WVCaver2011 wrote:Has anyone been able to reproduce these "Key parts" besides the company that makes the upgrade kit? :shrug:


Nobody knows for which purpose originally custom made chip which this "one-man company" ;) used as main part of the upgrade kit.
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