Yes it does work if you have cell signals hitting your roof area. Before buying, I went into the attic and checked that I was receiving a good enough cell signal on my phone (3-4 bars). We have a two story home. I installed it in the attic, at the top of the roof line and ran the cable through a hole I drilled in a closet ceiling. I was concerned that I needed to bring the cable all the way to the first floor, but when I connected the sending unit upstairs in the bedroom, I received a good enough signal downstairs in the family room that I just kept the unit there and had a very simple install. There are still weak areas in our house where calls are dropped and during peak times when outside signal strength is low, we only get 1-2 bars inside, but just getting calls downstairs is a big improvement for us. If I wanted to move the sending unit downstairs I think I could make it work better. After 10+ years of frustration with lack of cell phone signal I am very pleased to have found this product!