SMC micro rack and DistoX2

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SMC micro rack and DistoX2

Postby bobby49 » Oct 20, 2019 3:24 pm

Some vertical cavers might use the SMC micro rack for descending, and they might use either stainless or aluminum bars on it. Stainless seems to be preferred. I do not know which alloy of stainless SMC uses, and I don't know how magnetic it might be. Does anybody have a magnet handy?

Some cave surveyors use a DistoX2, and it contains a sensitive magnetometer. This might get screwed up if the micro rack has too much of a magnetic property.

If I am trying to use both items, I might need to park my micro rack a ways down the passageway while I survey. Then I will forget it and it will be lost.

If anybody has both items, could you see if there is any magnetic interaction?
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Re: SMC micro rack and DistoX2

Postby trogman » Oct 21, 2019 5:52 pm

I have a BMS mini rack made out of stainless. It is not an SMC, so I have no idea whether or not they use the same grade of stainless. However, I tested it with my Disto X, and observed the following:
There was no influence at all until the rack was less than 1 foot away. I steadily moved it even closer, and even right next to the device it only changed the azimuth reading by .1°. When I approached the front of the instrument, the effect was greater, with a change of .5°.
I would surmise that as long as you keep the Disto more than a foot away it shouldn't be a problem. Even then, if it throws it off by .1°, that is not enough to be concerned about (in my opinion). Of course this is assuming that the SMC rack is made of the same type of stainless as the BMS.
I've taken multiple shots from the same spot and gotten .3° variation on many occasions. In such a case I will usually take an average.

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