No more DistoX calibration!

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No more DistoX calibration!

Postby saycomp » Jun 5, 2010 10:07 am

Hello!

Sory for my horrible english.

I think, I solved my problem with calibrating Disto X after each battery changing. Now, you must calibrate unit to the specified battery magnetisation.
After each battery changing you must recalibrate unit to other level and direction of batteries magnetisation. On this situation will be better every time use batteries with te same magnetisation (impossibile) or demagnetised. I construct very simply battery demagnetiser. It's 400 V coil from relay, box and switch. You must put battery into hole, switch demagnetiser on and slowly pull out battery to distance about 15 cm over demagnetiser. It's necessary repeat it on the
other side of battery. Sufficient time of "pulling out" the battery is about 3-4 seconds. It's necessary repeat battery demagnetisation before each Disto X use. It works!

It is good practice use this same type of batteries, best of all - rechargeable type. In my opinion best choise is Sony's CycleEnergy.

If you want realize measurments in other geographical region, you must recalibrate Distox, because of other magnetic inclination. Previous calibration can be saved (during calibration) and used again after come back. It's good practice make short, 5 shoot test of calibration before each use. Description of this procedure was recently added on DistoX page.

Now I think to construct mobile, AA battery powered demagnetiser. Sometimes it's not possibile connect to ~230V network
or generator.

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Best regards

saymon
saycomp
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Re: No more DistoX calibration!

Postby LWB » Jun 20, 2010 10:13 am

I'm not sure exactly what your device is doing, but I have found that all the Disto X's (4 total) that I have experimented require at least monthly calibration to produce data within acceptable foresight/backsight requirements. And the batteries (lithium) last about 6 months. And I occasionally have one that does not produce acceptable results immediately after recalibration (despite the calibration numbers appearing to be good). But the same Disto X will be okay after recalibrating again. A mystery...

I would certainly run a compass test course checking foresights and backsights before each use. The elevation errors seem to stay the same after a month, but the azimuth error spread seems to about double (if 1/2 a degree after a calibration it will be about 1 degree a month later - if 1 deg after calibration it will be 2 degrees a month later).

I certainly recommend monthly recalibration as a minimum. And run a test course before using regardless.
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Re: No more DistoX calibration!

Postby saycomp » Jun 21, 2010 1:58 pm

Hello!

I'm not sure exactly what your device is doing


Please read my previous post attentively. I explained my idea shortly but clear (I hope). :-) It's simply. Just reduce magnetization of battery to very low value. Like degauss function in old, CRT displays.

the Disto X's (4 total) that I have experimented require at least monthly calibration to produce data within acceptable foresight/backsight requirements. And the batteries (lithium) last about 6 months


A large majority of batteries contains ferromagnetic (iron) parts. These parts are subjected to slowly magnetization caused by earth magnetic field (during measuring this field disturb the earth magnetic field). I made a lot of tests (with 3 units) and I confirm, that DistoX's sensors are very stable. When I use this same (rechargeable), demagnetized before each use batteries I achieve error less than 1 deg without recalibration.

Best regards

saymon
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Re: No more DistoX calibration!

Postby LWB » Jun 27, 2010 4:05 pm

Saymon,

Okay. Maybe demagnetizing the batteries will result in a longer lasting calibration. I'm willing to test it. Are you selling these units? How do you get one? I don't happen to have any demagnetizers laying around the house.
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Re: No more DistoX calibration!

Postby lowmoor » Feb 26, 2011 8:13 pm

:kewl:

Thanks for a really good and practical idea! :clap:

I have made and used demagnetizers before for other purposes, and plan to use your method in the future.

Thank you again for the very good idea!

Regards: Bill Gordon
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Re: No more DistoX calibration!

Postby Bob Thrun » Feb 28, 2011 8:34 pm

saycomp wrote:I think, I solved my problem with calibrating Disto X after each battery changing. Now, you must calibrate unit to the specified battery magnetisation.

Is that the reason the Disto X and similar instruments have to be calibrated? I have never seen or used a Disto X. With hindsight, I think I would have noticed puting steel-cased batteries into a compass unit. Most surveyors keep their light a a couple feet away from the compass when reading it.

Better than demagnetizing the batteries would to use non-magnetic batteries. Most batteries are sheathed in steel since Ray-O-Vac's patent expired. I have a marine compass that lights up a red dot in the viewfinder. It uses a carbon-zinc AAA cell with no steel sheath. I have to go to a battery store to get it. Carbon-zinc batteries are the oldest chemistry for flashlight batteries and have lower energy than alkaline cells. I have not seen an alkaline cell with no steel sheath. I do not know about lithium or rechargeables. It may be possible to remove the steel sheath from the batteries.
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