RFD 900x Telemetry Issues w/ QGroundControl/Mission Planner

Hello! My name is Ethan Roe, and I am a student at Indiana State University. I am emailing you because we are in an Unmanned Systems Mechanics class, and are building a quadcopter with the stock Pixhawk Cube and the RFD900X. I have CC’d my instructor, my 2 TA’s, and my other group members.

We have not been able to enable the RC functionality of the modem. We attempted to change baud rate, but were unsuccessful in Mission Planner. We were attempting to find the setting based on a tutorial on the Pixhawk website but were not able to because the setting was not present in the program. We weren’t able to do a loop-back test because of hardware limitations. We weren’t actually able to configure the hardware to perform the test safely. We also tried updating both modems to the 3.07 firmware as we were advised to by RFDesign, the manufacturer that made the RFD 900x.

We are currently engaged in a quadcopter build, with a pixhawk cube and the RFD900X and the Spektrum FPV Racing Serial Receiver. Our issue is that in Mission Planner and QGroundControl, we are unable to receive any telemetry information, and are unsure where our actual issue is. We have posted on several forums, and looked at different pinouts for the cube and the RFD900x, but have yet to find anything that can resolve the issue.

Any help is greatly appreciated!

When you power the RFD900 after a few second what is the red and green LED behavior?

Have you posted to discuss.ardupilot.org?
First two things I’d check: reset both radios to defaults, and make sure the air radio is powered separately from your autopilot (not via the telemetry port).

Hello dear friend
Good luck in developing knowledge

you may need to change the baudrate of telemetry port which you have connected you RFD900 to

you can do it through mission planner by searching Serial_X baudrate which x is the number of serial port on your px4

tell me what you get after testing it


Is this true?
The FCC and Industry Canada regulations link the maximum transmitter
output power and the number of hopping channels in a frequency hopping
system. A transmitter with 50 or more hopping channels is allowed up to
1W of output power. A transmitter with at least 25 channels is allowed up
to 0.25W of output power.

ı had same problem, ı could connect rfd 868x in rfd interface, also see in mission planner sik radio but could not connect in mp. ı realized that ı connect rx tx pins in the telemetry on UAV backwards. just changed them then worked well. the problem is original pixhawk pinout dataseet in the internet where ı looked for is wrong.