The HDA Series of 19″ rack mount headend distribution amplifiers are completely self-contained broadband devices, specifically designed for the distribution of digital and analog CATV signals in the frequency range from 47 to 860 MHz. The HDA is unique in the fact that it integrates the abilities of a passive combiner and a distribution amplifier into a single high performance unit. State of the art hybrid power doubling amplifier modules enable the unit to operate at high output levels while maintaining low distortion characteristics. Four combiner configurations of 16, 12, 8 and 4 ports are available. A -30 dB low-level back matched test port is externally accessible enabling easy in-service testing and adjustment. The chassis design affords excellent heat dissipation allowing operation at high ambient temperatures without sacrificing reliability. Plus, the HDA has a built-in standby power supply with automatic switching capabilities.