Magnetic contamination can be a problem, though rarely. Most often this is caused when a “permanent” magnetic component was accidentally attached to or close to one of the sensors. This can cause big shifts randomly in the data from one or both sensors. Check by removing the sensor door and visually inspect the two MFAM sensors and their surrounding areas for anything unusual.
If you have another magnetometer, like the G-864, you can also measure the magnetic signature of the sensor part of the MagArrow with the following instructions.
- Turn on the magnetometer
- Wave the sensor part of the MagArrow above the magnetometer (as close as possible but not touching)
- Wave in both west and east directions
- Check whether this is any magnetometer reading change when the MagArrow passes by
- If reading changes are observed, there must be some contamination.