One or two times per operating session my recently assembled Rev 4 QDX fails to return to receive mode after a transmission completes. I'm using VOX and currently don't have a good way to use CAT to toggle between TX/RX.
The LED repeats the two flashes indicating low audio level from the PC. However, no audio is being sent to the QDX at all so it should return to receive mode.
Things I have checked/tried while the 2 flashes are happening:
- Both lowering the volume on the PC and muting it - No effect, flashes continue
- Unplugging the QDX's USB cable from the PC - No effect, flashes continue
- Checking Input Analysis shows NO SIGNAL
- Transmitting from the Transmitter Test menu in the QDX terminal (No changes to PC) - Flips it back to receive/normal function.
- Power cycling the QDX - Returns to normal operation
As this doesn't stop even when the USB cable is removed I don't think there's anything on the PC causing it. The QDX otherwise works great. It has happened both when transmitting into my antennas and on my test bench into a dummy load so I don't think it is an RF problem.
My best guess would be a firmware bug but I don't see any mention of others seeing this issue. Maybe not a lot of VOX users?
QDX Rev 4 with 1_10 firmware.
I would be open to it being an assembly issue but I can't think of anything that would make the QDX think a stream of bits are being sent to it when the USB cable isn't even connected. If anyone has an idea of something I should check let me know.?
