Clayton, One issue in using magnetometers for azimuth determination is the fact that the sensitivity to bias and scale factor errors increases when crossed instruments are used to measure the field. In a system I designed in the past we used a single axis magnetometer and rotated it to null out the reading. The angle to the magnetic field was measured by the angle of rotation required. The instrument was mounted on a ~ 1 ft. plastic shaft to isolate it from the rotation motor and other sources of error. You could mount the magnetometer on a simple stepper motor rotator and get better performance as the expense of some complexity. But it might be a fun DIY project. Another thing I could offer is I do have some software which calculates the vector field at any location from the current geomagnetic field model which is available on the internet. But you can do just about as well with any current aeronautical chart.
BTW - Thanks for our QSO of earlier today on AO-85.
Regards, Al Watts - AF5VH
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Clayton W5PFG Sent: Thursday, February 18, 2016 11:58 AM To: AMSAT-BB amsat-bb@amsat.org Subject: [amsat-bb] Remote sensor for antenna array orientation
Has anyone ever mounted a mutli-axis accelerometer or a magnetic compass sensor to their antenna crossboom for making adjustments to point of aim?
I'm currently using Hall Effect sensors but experiencing several degrees of drift over a short period of a few days.
73 Clayton W5PFG
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