Deviation between the values of C3_MAX and RC3_MIN and the PWM signal output from the radio

Issue: I am experiencing a discrepancy between the configured RC3_MAX and RC3_MIN values and the PWM output from my FUTABA T6K transmitter when connected to my PC via WSC-1 and used as a joystick in Mission Planner. This has led to a pre-arm check error stating “throttle is not neutral.”

Environment: I’m using Mission Planner along with ArduCopter (V4.4.3) running on SITL.

Details: After conducting radio calibration in Mission Planner, I set RC3_MAX to 1820 and RC3_MIN to 1180. However, when I checked the values again post-calibration, I could only get a range between 1704 and 1295, which does not meet the full parameter setting for RC3_MIN, triggering the pre-arm check error. I have also observed similar discrepancies (attenuation) between the configured MIN-MAX values and the actual PWM outputs for other RCn channels. This issue did not occur when using a Nintendo ProController as a joystick, leading me to believe that the problem may not be with Mission Planner itself.

Any advice or insights would be greatly appreciated.