I use this Dual Band booster at a lake house. Metal roof and down in a valley at a lake. Outside if I hold my cell phone up in the air I get a good signal. Inside the house, nothing. With this booster I get 4-5 bars. Dual-band device works with 800/1900 MHz frequencies from all major carriers--AT&T, Sprint, T-Mobile, Verizon, Alltel, Cricket, and more (not compatible with Nextel). We got the dual band, a little more expensive, because I have ATT and my brother has T-Mobile. They use different technologies/bands. I am very happy with the results. As stated above, you place an antenna outside and run a cable to the unit inside. It also boost my signal when out in the yard. I had one for about 2-3 years and I think it was fried by lightning. I did not hesitate to spend the money on a replacement. I have had the current one for about 5 years. You can disconnect it when you are not there to reduce that risk.
About $200.
Link to unit on Amazon
