Either AT&T has no roaming agreement or it's GSM technology isn't broadcast. At Trailjam with the 2watt and 3watt system I had 2-3 bars of service with Verizon on Extended Network (Roaming). On the Nile road I had 3-4 bars of service with the 2watt booster. Off the Nile Rd on Cloversprings Road I had 2 bars of service at the Cattle Guard. 4 bars of service at the Woodshed.
I had 2 bars of service on most of Kaner Quartz Eastbound. Up until I severed the antenna wire against a tree I had 2 bars of service on Rocky Saddle. I still had the antenna wire temped around the windshield frame. I saw the tree. Figured the new armor would handle it. Oops.
I had quite a few people use the booster in camp to call for parts. I made various calls while on the trail. Never had a problem. Very pleased with the performance.
93' YJ w/factory hood