[TowerTalk] Smart Phone Compass

[James Wolf]

I can't speak for all smartphones, but those that use real magnetic
information for direction use a magnometer.  Some use a 2 axis and some a 3
axis.  
With the latest chips, there is some compensation for any close magnetic
material during calibration, but it can't do it all.  The closer you are to
other magnetic objects the more error will be introduced.  Calibration done
correctly is also somewhat critical.

The use of a demagnetizer on the phone is sometimes needed to remove
residual magnetism to get accurate results.   The wildcard is this:  How
much magnetic material is in the phone and how accurate do you need to be.
The chips are usually accurate to about 1 degree, but that is usually
optimistic when installed in the final device.

Jim - KR9U


------- Original message -------
> From: Wayne Kline <w3ea at hotmail.com>
> To: towertalk at contesting.com
> Sent: 23.12.'14,  21:37
>
>  OK  I do not want this to morph into the many proven ways to find 
> TRUE north.
>
> The compass extra on a I phone..... True north .... I assume it is via 
> GPS tribulation ??/
>
>
>   Wayne W3EA
>
> PS   Merry Xmas  and Hpy Holidays to ALL  TT'ers
>
>
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