Thanks for the link. No distance measurements are taken. We placed the azimuth targets (PVC pipes placed in sockets on the ground) farther away in order to get a more precise azimuth alignment. But the details are dependent on the user, and how good their eyesight is, and how steady the hand.
Of course if you have several X2s for calibration check, we also just compare standard readings in two directions, FS & BS, because it is faster. It is always best to check cal at the cave since the magnetics at home may be different. That 3-D printed fixture (and others seen on the internet) are quick and easy, but if your laser beam is not aligned with the flat sides of the unit there could be a slight error. I have also heard of people shimming the sides of their unit with tape, which is good if you are using the quick fixture. - Pete On Jul 23, 2019, at 3:32 PM, mmin...@caver.net wrote: Pete, The hardware is the same. You can get the firmware update here: <https://paperless.bheeb.ch/download.html>. Scroll down to DistoX2 Firmware. Current is version 25. As I understand it, you don't need to take distance measurements at all for calibration (which means the laser doesn't need to hit a target). What is important is holding the unit at the proper angles and rotations. Dwight Livingston used a 3-D printer to create a stand that has all of the positions built in. It was only about a foot long on each side. I've seen other similarly small frames for calibration made of wood or PVC. Mark On 2019-07-23 16:54, Pete Lindsley wrote: > So Mark, can you update previous X2 conversions? > We use a Brunton/Suunto compass course at Fort Stanton which has a > center point with 6 radial points ~ 50 feet away. We have extra > sockets near one of the radial points just 4 feet away for the +\- 45 > degree inclination shots. We use the 50 foot points for the Az compass > shots, and multiple calibrations can be done at the same time, usually > at dusk. > At home, I reduced this to three posts 15-20 apart, and two more 4 > feet away. See attached sketch. > - Pete > On Jul 23, 2019, at 2:30 PM, mmin...@caver.net wrote: > On most expeditions I've been on, Distos are calibrated, or at least > checked, on site. At Carlsbad Caverns a couple of years ago, we > calibrated the Distos _in_ the cave at the beginning of survey. We got > great backsight agreement and awesome closures. One very large loop > closed with under a foot of error. We've had similar closure success > in Warm River Cave, where we closed a 2300-foot loop with 0.1% error. > Of course if the data are good, large loops should close better than > small ones because minor random errors will tend to cancel out. Not so > for systematic errors like from miscalibrated instruments. > The current DistoX2 firmware has a feature that compares the last > three shots and if they agree to within 2 degrees (or whatever), the > instrument beeps and displays three dots. That way you know whether > your shots are good without having to look back and compare manually. > If you rotate the unit between shots it uses different sensors, and is > good for catching calibration errors. Of course taking actual > backsights is still advisable because that's the only way to detect > possible magnetic anomalies. > In actual practice we find that if treated well, the DistoX2 generally > stays within calibration over long periods of time and from one place > to another, within reason. > Mark Minton > On 2019-07-23 14:07, Pete Lindsley wrote: >> DIsto X2s are great in a cave when they are calibrated. I have >> modified 6 units so far with 2 more on the bench. One of those I >> suspect has a bad daughterboard. I found out the other Disto had an >> issue before I took it apart. It helps to calibrate the units before >> going into a cave. At Stanton we have found bad calibrations both >> during a survey or afterwards. Ditto for Bruntons & Suuntos. So you >> need to be able to calibrate the DIsto X2 in the cave, which means you >> need to carry in your Android phone or tablet. (The Brunton is more >> rugged than those smart devices, and may be a worthy backup unit.) >> All of the Suuntos I have bought have only lasted for 3-4 years before >> you have to replace the clouded up “smart part”, at just slightly >> less cost than a brand new Suunto. The Suuntos can also have compass & >> inclination errors (like Disto & Bruntons) but few people bother to >> check calibration. At least the Suuntos are waterproof. Suuntos & >> Bruntons work well in the daylight, not so much the Distos. >> For the Disto units where the laser does not align with the sides of >> the unit, you certainly need to carefully run a calibration that >> rotates the unit on all 4 sides. Some of the calibration videos out >> there don’t do that. >> I started off with a used tripod-mounted quadrant Brunton using the >> Shadow Method. We ran the closure data in Carlsbad against Tom >> Rohr’s theodolite and precision level survey using the >> Hardy-Corcoran Fortran program on an IBM 360. Overkill for your >> smaller caves, but we made pretty good FS/BS measurements out to ~ 100 >> feet. Over the last 15+ years the Fort Stanton Snowy River surveys >> have used all of these devices and our sketching techniques have >> improved 200%, partially because it is so easy to use the Disto to >> accurately shoot in the key sketched items. The Suuntos apparently >> introduced blunders, and perhaps lazy FS/BS techniques, because some >> of those older surveys appear to show that water runs uphill. >> Our new trick is an Arduino controlled data logging barometer that we >> hope will help sort out these past elevation errors. I am hoping we >> can kill off some of our 20 foot elevation closure errors from old >> Suunto surveys with the baro units quickly checking the route. When >> your 12 mile long stream passage has an average inclination of ~0.2 >> degrees, careful backsights become very important. It might even help >> to mount your Disto-X2 on a tripod and take instrument height / light >> height data like we were doing 50 years ago with the lowly Brunton. >> Hand-held 200 foot Disto shots usually have quite a bit of >> “wiggle” if you are trying for 0.5 degree precision. >> - Pete -- You received this message because you are subscribed to the Google Groups "Southwestern Cavers of the National Speleological Society" group. To unsubscribe from this group and stop receiving emails from it, send an email to swrcavers+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/swrcavers/ed2066bae1cc5efad687ea0a10257fa1%40caver.net. _______________________________________________ Texascavers mailing list | http://texascavers.com Texascavers@texascavers.com | Archives: http://www.mail-archive.com/texascavers@texascavers.com/ http://lists.texascavers.com/listinfo/texascavers
