On Mon, Mar 31, 2025 at 09:00 AM, Erik Larson wrote:
My QMX+ is showing some signal every 500Hz in USB mode (and in DIGI mode) on RX.
This is also happening on my QMX+ in Digi mode into WSJT-x.
So it should have nothing to do with AGC or with the SSB update - ?the SSB firmware should not have changed the Digi signal path, excepting some bug, and AGC is not in the data path in Digi mode, nor is any of the audio output or microphone wizardry.?
?
Their amplitude is quite low, even on 6m where they are most prominent - but in my case, the positions of the birdies are somewhat different on the lower bands except 10m.? I can reduce the amplitude a bit by touching or messing around with the 6m BPF and LPF, but they are still there, with the ones at 1500 and 3000 most prominent by far.? And they are there at the same amplitude even with a dummy load and different power supplies, so their source seems likely to be internal to the QMX+.
