i was very skeptical about this product after reading some of the negative reviews. after trying a couple of different installations, this thing works awesome. my office is an old industrial building with a tin roof, att got barely 1 bar inside but full coverage outside. we initially tried installing the large antenna against the outer wall, with the repeater about 50ft away. this didn't work, the repeater's signal constantly interfered with the large antenna. then we installed the large antenna on the outside of the building, about 80 ft away. this was the trick, being on the outside, the signals never interfered and now we get full coverage inside the building.totally worth the money!