No Green Bars in Radio Calibration

QX7 - R9M - R9MM - Pixhawk 2.4.8 - MP 1.3.7
I can do the Accelerometer and Compass calibration but when I get to Radio Calibration there are no green bars. The radio is on and bound to the receiver. The receiver shows a green light and the radio is receiving telemetry (RSSI) but there does not seem to be any information going out to the Pixhawk on stick or switch positions. The channels are set as in the Pixhawk manual. What am I doing wrong? I hope it is something stupid that I have missed.

Did you plug the receiver into the RCIN port of the flight controller ? (First from left, not the second marked SBUS, that’s an output)

Thanks for the quick response. Yes, I did plug the receiver into the RCIN port with the black I(-) wire on top and the signal wire at the bottom. I also know the wiring to the receiver is correct because I had no trouble programming it or binding it.

Any other thoughts?

The fact that you see no green bars indicates the Pixhawk is not getting information from the receiver. That new receiver has an inverted s.bus signal which might be causing your problem. I would get/borrow a cheap older “normal” frsky receiver and see if it works.

I’m thinking the same way. I’m a snowbird in Arizona so I don’t have access to another receiver so I have been pricing a X8R that I can get in 3 business days and go back to 2.4 GHz and get it to work and then work on going to the R9MM. Your thoughts?

I’m using the S.port/F.port? Is that right or should I be using the Sbus_Out port?

I found a video on Youtube showing connecting the signal wire from the Pixhawk to the Sbus-out of a R9Slim receiver. I did not realize you use the S.port only for flashing the firmware to the receiver and then use the SBus-Out to connect to the Pixhawk. My Bad and as I thought, a stupid mistake that is actually easy to solve.

I have not done this yet but could someone confirm what I just said before I go ahead. Thanks!


I am using Pixhawk Cube Orange , FrSky Taranis X9D+ 2019, +R9, M.P. 1.3.78 and ArduCoptor V4.0.2.

I have the same issue.

My R9 is connected with R9M. Somehow I can’t see green bars on Mission Planner. I use Taranis X9D+ 2019
Cable is connected as it should be, SBUS Out (R9) to RCIN Pixhawk Cube.

Weird thing is If I select PPM Mode in taranis it immediately works. As soon as I select R9M EU mode Green bars in mission planner disappears. For both of the modes Green light on receiver is present that means transmitter is connected to receiver.

Just to mention RX8R with internal RF works perfectly.

I don’t know if the R9M (EU) protocol isn’t compatible with Pixhawk Cube.