I have two 3DR Pixhawk Minis and neither will detect a RC signal for calibration using QGC. I've tried various firmware, latest stable / master / some previous and no luck. When I go to calibrate radio i get the above error message and the lights go out on my FrSky X4R-SB. I've tried two seperate X4R-SB receivers, both SBUS and PPM, and a R-XSR all of which work fine with other drone builds. I'm lost as to what to do next.
If anyone could help me I'd really appreciate it. Thanks