Boosters duplicate your outside signal strength for about a 25 feet radius through walls INSIDE your home. If the outside signal is weak, a Yagi antenna can help a great deal. The YX500 Cel booster is a half Watt. I wish it were 5 Watts. Depending on the signal strength atop my roof, I can walk around my home of 1800 square feet and still drop a call. The Yagi usually adds two bars of signal strength to the zero bars outside. My phone often works with less than one bar.