I have generally -75 to -90 dB of 4G and 3G signal at both work and home in Metro DC. In both places, I have seen the phone lose all data connectivity randomly AND it drops whatever call is currently taking place. I initially thought it was because I kept changing the 3G/4G settings via the *#*#4636#*#* setting, so I did a factory reset. But again, I've seen it lose all connectivity. Does it sound like my phone is faulty?