Compassmot exceeding limits

I have done the compassmot and got a value of 220%. Way to high.
Can anyone give tips on reducing this to an acceptable level? I know twisting of cables etc. But wonder if a metal shield between the pdb an the fc can help.
Or is an external compass the only feasible solution?

I assume that you are using an APM2.5 with an onboard compass?
Yes, switching to an external compass will allow you to move the compass to a position that will be less affected by magnetic fields.
TCIII Developer

Correct, I have the onboard compass only. I already have a GPS unit. Is there an external compass I can fit in combination with the external GPS, or is the combo GPS/Compass the only solution? E.g. this one … th-compass.

Guess that a separate compass will do.

Your options are to increase distance between the PDB and APM, or to get an external magnetometer.

Shielding will not affect the DC (unchanging) magnetic field from the PDB.