[Erythros]

Changing radios gave me this problem at times. Certain radios which didn't work particularly well for my area did this rather often. My most current radio does not do this at all. I now get great coverage from my radio. A PRL Update shouldn't necessarily fix this issue for you, but if it does then leave it alone. Otherwise I would suggest sampling different radios until you fine one that provides the best coverage for your location.
The nice thing about a radio update is that you do not have to Hard reset your device.