I just got my XRX and i'm awaiting an auxillary power plug to be completed in the aircraft, so i've been playing with the unit in my car. My understanding from the manual is that the XRX is "calibrated at the factory" and should not need calibration. I looked at the heading/altitude indicated on the unit and it was way off (heading wise at least) i reset it to 360 and it seemed to track okay. I backed into my driveway starting by facing north and doing a 90 to face west and the compass indicated a heading of 180 instead of 270. I've re-calibrated, turned the unit off, placed it to 270 and turned the unit on and it was still off.

Am I somehow having this problem because i'm using it in a car and not an airplane?? How often would one reasonably have to recalibrate a unit that is taken in and out of the plane after each use?

Also, i may have missed it - but you may want to make it clear in the manual that the external audio alerts only occur when the traffic is getting close as opposed to when it is first picked up. I racked my brain for a while trying to figure out why a target 5 miles out didn't beep when it first was acquired, I thought the unit was broken.