My phone can be sitting on my desk & it still has less signal than my 3G. I did put a "bumper" type case on but that is only for protection. I talked to an AT&T rep in person (a really nice guy who seems honest) & he said that AT&T is doing such a massive upgrade that towers get shut down so all traffic goes thru fewer towers. I'll give them the benefit of the doubt because their reputation is fast going down the chute & Apple will be exerting MAX pressure with the threat of switching carriers. Still love my iPhone(s).
This. Has. Nothing. To. Do. With. AT&T.