Having problems with my 4S's reception with AT&T in a place (my home) where reception previously was great. Went to the Apple store yesterday and got a new 4S...It has the same reception problems. The conversation sounds fine at my end for a few minutes, and then it sounds as if the other person is underwater. The other person on the other end of the call hears me fine. My wife also has a 4S and her reception is great so I don't believe it's a tower issue. Ideas?