Using QGroundControl with PixHawk + Taranis X9D

Hello, another puzzled RC noob here.

It’s been a learning curve, a lot to take in and understand. I looked for a more specific subcategory, where I could ask system specific questions about my mix of Transmitter (RC Controller) , flight controller, ground control software & communication protocols.

I have posted in Using QGroundControl subcategory, a specific question about GGC. Pretty quiet over there…

I have a nearly complete Tarot hexacopter on which I haven’t been able to test spin the 6 motors.

I believed I’ve narrowed it down to the fact that QGC, running on my Android tablet, can’t “hear” my Taranis X9D Controller.

When I attempt to pass preflight, it fails unless I connect the PixHawk flight controller directly to GGC with a USB cable. Even so, QGC insists “Not Connected” and the Transmitter icon is gray.

When I try to Calibrate the joysticks using QGC, I get an error message
"0 channels detected. PixHawk needs at least 5 channels’

I’ve searched that error message online with few results, no solutions

I have 8 channels configured in the X9D so far. And please note I get good RSSI readings between the X9D controller and the Receivers onboard the hexcopter.

I do have the WiFi enabled on the tablet, but maybe I need some specific antenna for the X9D to communicate (using radios frequencies) with the tablet (running GGC)?

QGC informs me on the Radio setup menu that it “already knows” most common comm protocols. But maybe it needs extra hardware to communicate?

Maybe my theory is completely off track. Any thoughts? Thanks.

Replying to my own post.

I’ve started looking at the idea that
my PixHawk is not detecting the onboard Receiver
plugged into the RC In pins.

Receiver is getting powered by the RC In - and + pins, and is bound to my RC Controller
showing good RSSI values.

QGC reports error “0 radio channels detected. PixHawk needs at least 5 channels”.

Maybe that error message originated from the PixHawk, and somehow
QGC got the message. MavLink? was it via WiFi? I don’t know!

More later.

The symptoms you describe look to me that your pixhawk is not receiving a RC signal from the reciever. You have to consult the docu.

It’s clearer to me now. I was thinking “two way radio communication”.
It is, but not exactly. It’s more like two one way streets side by side.

The RC Controller is called a Transmitter for a reason…
it sends commands from joysticks, switches, etc. one way,
to the Receiver on the aircraft.

Getting telemetry back down is a separate one way path. A flight controller
usually has a port for a telemetry radio transmitter, which is paired to
a telemetry radio receiver, usually connected to some form of ground control software.

Mine is a YRRC implementation of a 915MHz Radio Modem running
Sik firmware, plugged into TELEM 1. The YRRC’s default baud rate
is same as that of TELEM 1.

The error message is from the flight controller, coming back on
the telemetry channel to wherever you saw the message. In my case
it was QGroundControl.

I hate to say it, but I think my Receiver issue was a signal pin not “locked” in the connector. It pulled back just enough to lose contact. No radio channel signals passing into the flight controller.

I hope this information proves useful.