What do these system consist of?
They are often called BDA systems which stands for Bi-Directional Amplifier or signal booster systems. Though there's a lot more to them than just the BDA. In most systems a rooftop donor antenna picks up RF signals from the emergency responder's radio network. The signal is transported by cable to the BDA where it is amplified by up to a billion times it's original strength. Then via a network of coaxial cables, splitters, couplers and indoor antennas the RF signal is distributed throughout the building. It also operates in the opposite direction to pick up the transmissions from first responders inside the building, relays the signal to the BDA where it's amplified and transmitted toward the public safety radio network, assuring critical communications are heard loud and clear.
