When I turn on LTE, I get 1 bar but when I turn it off I get 5 bars 3G. I live on the 14th floor (unobstructed) in a busy neighborhood in Brooklyn that is listed as having good service. My neighbor has 5 bars but me, merely 1. I just got a replacement 5S at the Apple Store in case the antenna was defective but now it is still stuck at 1 bar. Help. I have the newest IOS update.