Additional information for using the I/Q output as a PC Panadapter. Note that I have no hardware low-pass filter on the I/Q signal.
1. My desktop has a discrete connector for the stereo microphone input. My laptop has a TRRS (tip, ring, ring, sleeve) connector for both stereo sound output and mono mic input - can't use a mono mic input for I/Q - must be stereo.
2. In SDR#, the source selection must be "IQ from sound card". Also on my PC, SDR# won't work for IQ input if external speakers are plugged in - in which case all I get on the display is noise - don't know why.
3. Of course, in Windows 10, whatever stereo microphone input that one is using must be the selected/default microphone in the sound settings and the levels must be properly set.
To get rid of the above VFO severe birdie/aliasing, I set the VFO for 7073 and displayed 7074-7076.5. Here's what the FT8 signals looked like: