Spektrum issues with Pixhawk

Hey everyone!

I’m really having trouble determining why my Spektrum 4651T receiver won’t communicate with my Pixhawk flight controller.

I’m using ArduPilot Mission Planner V1.3.72 and ArduCopter V4.0.3 to set everything up.
The 4651T receiver is connect to the SPKT/DSM port on the Pixhawk. I can get my Spektrum DX8 G2 transmitter to bind to the 4651T receiver if I manually push the bind button. So there is power going to the receiver from the Pixhawk. But when trying to calibrate the radio in Mission Planner, there is no indication of a connection. No green bars, not signal input, just blank. Therefore of course, my UAV will not fly.
I’ve been trying to find an answer on many forums as to why a Spektrum receiver may not communicate with the Pixhawk without any luck yet.
The receiver and transmitter are bound on DSMX at 11ms frame rate.

Below is all the equipment listed for reference:

Really hoping someone can help??

Thank you,


@Deloyer You’ll likely need to provide quite a bit more detail for any help to be provided. Some suggestions:

  • Clearly show all connections (create a simple wiring diagram if needed, or copy one)
  • Have you gone through all Pixhawk configurations and changed from RC to serial input (sounds like it’s waiting for RC input still)
  • Double-checked that the pinout from the serial receiver is the same as the Pixhawk
  • Double-checked the settings for the communication (port and baud rate if they can be changed)

Thanks for your response:)

I have swapped radio systems to FrSky and will try this out soon. I’ve seen too many other forums with Spektrum Pixhawk issues without conclusions. The FrySky seems to be much more common and reliable. I’ll post how this works out.


I have recently purchased a Spektrum SPM4651t receiver to replace the original spm4649t that my quadcopter came with. I also am having issues with the receiver not showing any signs of life after binding and I have all Spektrum components. If you have had any luck getting yours to work I would appreciate any tips on how you did it. I am currently waiting for a response from Spektrum technical support regarding this issue so if I get a fix for this problem I will gladly share it with you. If you have given up on the Spektrum I understand as that will be my next choice. It’s helpful to hear that someone is having the same issue.