Casio G'zOne Type-V

I am on my third type V. After a period of time, the antenna signal is very weak and I can't get any reception in fringe areas. When the phone is new it works great but over time something degrades. Verizon has swapped out the phone each time.

Anyone have any idea what may be going on? Other phones in the precise spot show a stronger signal. *228 has no effect on the problem. Thanks