We are having the issue in Q ground control with it not recognizing the transmitter whenever we go to calibrate in the radio section. It says to turn it on, but the issue is it already is on and it says that it is connected to the RC. We suspect it might have something to do with the Pixhawk not recognizing the transmitter. We tried different things like unbinding and rebinding the transmitter to the RC and disconnecting and reconnecting the connections between the Pixhawk and RC but nothing seems to solve the issue and in QGroundControl the same error appears “Radio Not Ready, please turn on transmitter”.
Can you post some pictures and show us your setup, how things are connected, etc?
Something seems like it may be incorrectly connected.