A stick's calibrated range is too small

What ArduPilot says:

• PreArm: … radio min too high
• PreArm: … radio max too low

For roll, pitch, throttle and yaw, ArduPilot expects the calibrated minimum (RCn_MIN) to be 1300 µs or lower and the maximum (RCn_MAX) 1700 µs or higher. The message names the stick whose range falls short: the calibration did not see it travel end to end.

What to do, most likely first

1. The radio calibration was never done, or the stick was not moved to both ends during it.

   CheckIn the Radio Calibration screen move the named stick end to end: the bar should run from about 1000 to about 2000.

   FixCalibrate the radio again, moving every stick and switch to both ends several times before finishing.

2. The transmitter limits that channel's travel (end points, rates or a mix).

   CheckIf the bar stops well short of 1000 or 2000 with the stick at its end, look at the model's outputs in the transmitter.

   FixSet the channel's travel to 100% and remove rates and expo in the transmitter (ArduPilot has its own), then calibrate again.

3. The stick is on another channel than ArduPilot thinks.

   CheckMove one stick at a time and see which bar moves; RCMAP_ROLL, RCMAP_PITCH, RCMAP_THROTTLE and RCMAP_YAW say which channel ArduPilot reads for each.

   FixUse the AETR channel order in the transmitter, or set the RCMAP parameters to match yours and reboot; then calibrate.

Parameters to look at

Where to do it:Setup & Tuning Guide