What is a Passive DAS? A passive distributed antenna system (DAS) uses dedicated backhaul (leased line) per operator connected to a signal source AKA base station (3G, 4G etc), the signal of which is blasted with very high power via thick COAX cable direct to radio antennas. Passive DAS is very cheap as there are no active components, just COAX cable and antennas. However, they are suitable to a very limited size of building because the further the antenna is from the signal