Thank you for responding, you are the first to report the problem. Indeed, fixing this one line does not solve the problem, as I mentioned it together with the other settings. The monitor ribbon cable and the shielding between the RPi and the pcb greatly improve the quality of the incoming signal. What you did is the first step towards a good solution. I also went through these steps. The device in its delivered state cannot be used as described. What is described in the topic leads to the solution.
Indeed, I started using jtdx around 2017, following the childhood diseases of programming and using the radio, modem, PC I never encountered this message.
I was surprised when I searched with google and people complained about similar messages with wsjt-x. Mostly caused by RFI, lack of shielding, tangled wires. In this case, everything is in one place, so a more careful solution was needed.
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Gyula HA3HZ
HA3HZ