T-Mobile indicated that since my plan had roaming included, I was always connected to the strongest signal regardless of who the carrier was. The conclusion was, it was bad luck that all my lab locations had poor cell coverage from all the cellular providers.
High Tech House Calls changed to Verizon for all our cellphone needs. We have "3 bar" signal strength throughout the lab. The test for signal strength used similar model Blackberry models that should have eliminated differences a cellphones antenna.
Is it time for you to switch to a better cellphone network? www.verizon.com