Is there a truely effective cellphone amplifier system out there that works well in remote areas? I park my RV in a poor reception area the National Seashore on the tip of Cape Cod where the signal comes and goes sporatically. The towers with a direct line of sight are concentrated to the west 20 miles across Cape Cod Bay. There are a few to the South that aren't too effective. I tried a unit from Digital Antenna and determined it to be not very good after much frustration trying to keep it working. It only worked well in good reception areas. Any amplifier or antenna suggestions? JAHMAX