Same thing happend to me
I noticed the same thing yesterday morning. Being in IT and thinking I know everything I started to troubleshoot the problem. I uninstalled the few Apps I had installed on Wed night, rebooted 5 times, *18 to reset the signal, *226 - 2 to register. But to no avail, I ended up backing up my phone and Master resetting it, still nothing. I use tether my phone everyday to my laptop at work and have never had a problem so I was very confused when my signal kept completely dropping, then going to 4 bars, then to 3g, then dropping. I'm still not sure whats going on, but for some reason at work (Mid Michigan Area) I get no 3g and 1-4 bars (they tend to change every 15 sec or so) but at home (West Michigan) I get full 3g with no problem. I'm guessing one of the towers was damaged in our heavy storms a few days ago.
Verizon tech support called me back yesterday at 4pm when I was leaving home and everything was working, I agreed that the problem was solved and they closed the ticket, now I have to call them back and reopen another ticket:icon_eek:. Over all I don't think this is a problem with the phone as much as with the cell towers.
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Also I heard that turning Airplane mode On then Off sometimes resets the signal, but this also did not work.