What are the differences between active DAS and passive DAS?
Active DAS (also known as fiber DAS) typically refers to distributed antenna systems that use fiber optic cable to connect into a wireless carrier’s network via a base station. The high cost (typically $3–5 per square foot of coverage), lengthy implementation time (often 12 to 18 months), and carrier approval and licensing process for an active DAS system make it the right choice only for the largest buildings with high traffic (convention centers, airports, shopping malls, etc.).
Passive DAS uses antennas connected to one or more amplifiers via coax cable (usually 400-type or ½-inch coax) or fiber optic cable. Passive DAS systems gather wireless cellular signal with one or more antennas mounted on the roof of the building. The outdoor antennas are connected to one or more cell signal amplifiers, which boost the signal and broadcast it inside the building via ceiling-mounted antennas. Passive DAS systems have a much lower implementation cost (typically 50–70¢ per square foot of coverage), shorter implementation times (often only a few weeks), and use equipment preapproved by the carriers, making them the right choice for all but the largest buildings.
Active and passive DAS systems can both be implemented for general use, or as public safety systems for use by first responders.