As I’ve worked satellites over the holiday break I’ve been confused a couple of times as a pass has happened and there’s been no audible traffic at all. At first, I worried I had messed up my antenna somehow. It turns out that satellite operators, from time to time and for various reasons, turn off the radio functionality on the satellites!
Mark Hammond seems to be in the know about when this happens and regularly shares info on his Twitter feed. Check there to see if the satellite you’re planning to work early tomorrow morning has its radio turned on!
You can also see user-contributed status updates on satellite statuses at AMSAT.