tampa, fl here having the same issues. thought it was FB app specific but now its happening with almost every app i use. ive tried power cycling the phone, going to airplane mode, force closing apps it loses signal on. NOTHING has worked and its become very inconvenient. going to vzw store today to see wut my rep says. temporarily have the fone set to 3g (cdma) for now. will keep posted with whatever i find out.