Eerily this has been happening to me alot of late. It is pretty frustrating. Once I upgrade to 4.2.1 I also was upgraded to the GA02 radio and for a while my signal was greatly improved. Now especially at home I will pick up my phone and the data bars will be completely grey. Nothing fixes it. Soooometimes a restart makes me atleast get 3G. But yeah I have even had dropped calls recently and that had not happened to me ever since I purchased my phone. At home I am talking about 1 2 bars on 3G (when just a couple days ago it was full bars and sometimes even 3 on 4G) and yeah everything is all over the place here... when I go to different cities like Gardena, Torrance, Long Beach, Downey though I get great 4G and if not great 3G. The fastest LTE I have gotten on my phone is 19MB in Downey, CA.