me neither..after upgrade my iphone 4 to ios5..more frequently didnt get signal..it was full bar but actualy no coverage as i notice why phone kinda 'silence?' when i turn it off n on back,msg n miscal gettng in..now i have the solution as i juz on the cellular n 3g signal n it will be ok..no need to turn my phone off n on back..so far i notice it happen when i off my phone or batery kong dy ..