I have a Pi 3, setup with the satnogs image. Configured details and its showing as online. I can receive commercial radio with the V antenna set at the correct length but all my observations are coming up blank.
Having said that, when I get a “purple” waterfall - I reboot my station (sudo reboot), and that seems to solve the issue (for me). I’m sure you’ve already tried that, but if not - give it a whirl.