Southern DistoX's

[BruceMutton]

Has anyone successfully calibrated a DistoX in the southern hemisphere?

I have one that is refusing to be calibrated, and although I doubt the position on the planet is the problem, I guess I just need to check all avenues…

Bruce

[Ayayema]

Mine works fine. What sort of problems are you having?

A

[BruceMutton]

Hi Ayayema

Newly assembled upgrade (from Beat Heeb) to a Leica A3 Disto.

Appears to work fine and communicate with my desktop computer and Recon pda in all respects except for the rms error achieved during calibration.
I did a first rough calibration and got 0.9. Since then my best careful calibration has yielded 1.5, but typically 2.5.

Using it without calibration (I have no choice at this stage) - repeatability of readings is fine when sitting on a bench, but, for example if it is rolled about it's axis the magnetic values vary quite a bit - 6 to 10 degrees sometimes but 2 to 3 degees often. Gravity values are within 1 deg usually. Also when turned 180 degrees in a simple jig, the backbearing is about 8 deg out, whereas the back clino is within 0.2 deg usually.

It is as though it is extremely sensitive to vibration or under damped in a magnetic sense, as every few calibration shots gives spurious data. These may be correlated to the roll position(?). I have paid particular attention to achieving 3 sec focus times, avoiding movement on pressing the button (making a jig), avoiding such things as wristwatch, spectacle, headtorch magnetic interference, and checking that batteries do not rotate in the case.

I have yet to go to a really remote site and try to get it right to the nth degree, so until then I won't admit complete defeat.

[Ayayema]

It really sounds like there's something loose in there. I guess you've asked Beat for a diagnosis?

Mine was very close to correct the first time I switched it on and the calibration only made it better.
I've calibrated using a laptop (don't have a pocket PC), and with Auriga/Palm.

Palm in both south (Sydney-Jenolan) & north(southern Mexico) hemispheres.

I got a ~0.3 cal in the local inner-city park. I got about the same a long way from any known source of interference, So I figure that 0.3 is about the limit of how well I can point the laser hand-held but braced against a tree/rock/etc...and much better than I can do in a cave or with a Suunto.

The only bad reading problem I've had when the battery was low - started flipping the vertical by 90 degrees and the compass by 180.

A

[LWB]

Bruce,

Have you tested repeatability with the distance measurements? Perhaps the problem is in the A3 rather than the Disto X board, the calibration process, or Beat's firmware.

[BruceMutton]

LWB
Yes, distance, compass, clino are repeatable to a few mm and (often much) less than half a degree if the instrument is braced in EXACTLY the same place.

If it is hand held and using 'real survey conditions' natural uneven targets, repeatability is 10 to 20mm (half to 3/4 inch) and about half a degree.

The batteries are a snug fit, have marked and labelled them, they do not roll around or swap themselves over in the casing!
As soon as the instrument is rolled (so that the display is pointing to the right, say) errors in compass are apparent. Similarly if a back bearing is taken. Therfore I presume these errors are entirely related to callibration(?)

Bruce

[LWB]

Bruce,

It sounds like it is related to the laser alignment. For the Disto X, that is done with the first four shots (which is why you need fixed points for those). But, that doesn't answer why the laser alignment is working for others and not for you.