I tuned to CO this morning, and saw another trace on the spectrogram, about 500 up from its frequency:
As you can see, it's quite weak here - just barely visible on the waterfall, and barely perceptible by ear. It's weak and irregular enough that I can't tell if it's a regular recurring beacon, if it's half of a conversation, or if it's a steady carrier that I'm only getting sporadically. Anyone else see this?