i have the 3dr compass ( see pic ) its facing front as is the apm. yet when i point it north the compass things its facing south. i have calibrated it several times and still it does this.
any suggestions???
What is that APM board? If it’s a very old APM (pre 2.6), you need to disable to onboard compass to use the external one. If it’s a clone, good luck to you 
Did you select the correct compass orientation in Mission Planner on the compass calibration page? If you select the external 3DR GPS/compass it should give you the correct orientation. But if not, you can manually change it towards the bottom of that page.
yes its a 2.6 and yes i disabled the compass. and yes i did select the correct one on mission planner. its really weird.
if its backwards what should i sect to correct this from the many options listed?
ok switching rotation to non seems to have fixed that issue. lets see whats next