Well my best guess would be to use signal check pro so you can locate the sites you connect to. It will be a trial an error on finding which carrier is colocated with t mo. Most verizon sites here are very distinct compared to the other carriers. I know I've put pics up of all the carriers here in colorado. Here we are a samsung market for sprint. You will need to check out the equipment section so you can see what sprint equipment looks like and use process of elimination. Some at&t and T mo sites here can have different setups compared to others.