have another noob question. I was taught To Calibrate my compass every time I fly. I have been reading & looking at some videos. There are several that say not to calibrate unless you are more than 200 miles away from last flying location or having flight problems, etc. My question is if you do not calibrate before flight & you loose contact & try RTH, how does it know where to return to? I was under the impression that calibrating the compass before flight set your RTH point. If not, what sets the RTH point? I appreciate all the help trying to understand this complicated machine.