Have wireless broaband signal that bounces between 3 different towers. Verizon Tech Support did not even know how to access the field test in VZAccess Manager( Ctrl+D; password-diagvzw;click on Field Test)! Field Test reveals my signal bounces from Cellular Band 800MHz to PCS Band 1.9GHz; back and forth; back and forth. I know that an external directional antenna will solve this problem by allowing me to home in on the tower with the strongest signal. My question, which Verizon Tech Support seems unable to answer, is which frequency of a directional Grid antenna do I order--an 800MHz antenna or an 1.9GHz antenna? Unfortunately antenna doesn't come in 'dual' frequencies.