Compass settings

Merry Chrismas guys,

i’ve a compass issue with firmware V 3.1 on my old (standard) APM 1.4. After compass calibrating is is never showing exactly north (compared with a magnetic compass). There is a difference of approx 15 degree.

However, i tried a flight in simple mode. After takeoff, i noticed a small continous yaw but the quad was stable in the air and the feeling for the trottle was really great.

Possibly i did a mistake when calibrating in mission planner. Which compass type i shouldchoose (intern, extern, manual and which orientation)?

The heading that shows up in the mission planner is true north instead of magnetic north. The difference will come from the declination which will be automatically looked up from an internal lookup table using the GPS location.

 For the continuous yaw, that could be a number of things so we'd probably need to see a log file to know for sure.
        a) radio not calibrated or trim set on the transmitter
        b) compass orientation being off
        c) motors not balanced
        d) magnetic interference from the power lines under the APM

 I'm not totally sure what the orientation should be for the APM1 but my guess is that it should be either NONE (i.e. 0) or ROLL_180 (i.e. 8).  If it were me I'd point the vehicle North and then connect to the mission planner, go to the Flight Data screen, click the "Status" tab at the bottom and check the size of the mx, my, mz.  If the orientation is correct, X will be about 0, Y and Z numbers will be positive.