Areas needed DAS coverage that are long an narrow, such as tunnels, often utilize a special type of coaxial cable, called ‘radiating coax’ or ‘leaky feeder’. The coax cable is constructed with sealed perforations or slots along it’s entire length, that literally ‘leak’ out small amounts of radio signals to provide radio coveage in each area as the signals travel down the length of the coax. These can practically cover distances of up to a mile or more when coupled with the proper repeaters or other signal sources. And in-line booster amplifiers can be added to extend the total distance that can be covered to many miles.