They change sometimes then don't why
Try turning airplane mode on and off. This usually works for me. It beats having to reboot. My DX does this sometimes, but I can't explain why.
Droid 1 (was my back up, then let my son have it, and he drowned it within a week)
Chevy01 SS 4.8
ChevyNo1 1.1 Ghz MedV
Baseband --> C_01.43.01P
Droid X (My current back up, and he's not getting it)