I always wanted to know if the towers have to be able to almost see each other to communicate? If there are mountains in between must there be another tower to act as a repeater? I will soon have a new tower about 3 miles as the crow flies from my home but it will have a mountain in between. Not sure if I will get any signal from it and don't have any signal now, absolutely zero bars and Searching for service is all I get. So, the question is, do the towers have to be close to line of sight or can the signals travel over and up and down ground obstructions? Even the best phones on the market such as IPhone 5 and other smart phones are dumb as a box of rocks at my place.