The issue has been pinpointed. It's a D-Star signal from a new repeater on Contractors Peak [www.ircradio.org] that's in test coordination. A small amount of it makes its way into the San Gabriel Valley, causing interference in some regions. I'm in one of those regions right now.

In any case, it's a TASMA issue, or it will be if/when the interested repeater trustees get to work on it. After that, take a look around and play some fun free music games; it's also a good idea for starting classes in Elden Ring.