I am not really that much closer to figuring out why opposite sideband rejection is so poor, but I downloaded a couple of different SDR programs in the hopes that they might provide some diagnostic which might point more at the exact cause. Rocky still seems to be the best. PowerSDR seemed to work and has many cool features, but also seemed to pop and glitch occasionally. I also tried KGKSDR, which is a nifty program too, but which gave a glitch or two as well. I think the take away from all this is that sound cards suck.

But, a couple of interesting milestones with this: I decoded my first SSB signal with it yesterday (nifty!) and also my first PSK31 signal (Rocky has a built in decoder).

Oh, and I spent some time looking for a new scope. No luck yet.