Contemporary Research

QCA9-33 Active Combiner

QCA9 33 Active Combiner

The Contemporary Research QCA9-33, is an active RF combiner that features eight high-level inputs and one low-level input, combining with high isolation and amplifying up to a 33 dBmV output level.

Designed for QMOD HDTV applications, the eight RF inputs typically receive 29 dBmV RF from QMOD HDTV modulators. The ninth input is for up to 19 dBmV RF signals, such as incoming cable feed, a control channel from an ICE-HE Head End control modulator, or another QMOD or QCA9-33. Up to 8 QCA9-33 combiners can feed a single combiner to deliver up to 76 channels.
The extremely low-noise, wideband 860 MHz amplifier compensates for combining losses and adds 3 dBmV of gain, typically supplying a total output of up to 33 dBmV. Employing new RF technology, the QCA9-33 delivers higher isolation, quality, and noise performance over analog-era components; the noise factor is a very low 1.8, four or more times less than other active combiners.
The compact QCA9-33 mounts two-across in a single rack space using CR RK1 and RK-2 rack kits, and can be mixed with QMOD HDTV modulators using the same rack kits. The units are wholly designed and manufactured in the USA.


  • Combines 8 high-level channels (QMOD 29 dBmV) and one low level input (Cable, ICE-HE at 10-18 dBmV), cascade multiple QCA9-33 units for up to 72 channels in one array
  • Amplifies with a 3 dBmV net gain, up to maximum 33 dBmV output level
  • Provides high-isolation combining
  • Operates with an exremely low noise figure of 1.8, low power of less than 2W


  • Combine 9 inputs to drive a medium-sized RF system
    • 9 QMOD Modulators
    • 8 QMOD Modulators plus ICE-HE Head End
    • 8 QMOD Modulators plus cable feed
  • Feed output to a second CCA9-33 to combine up to 17 channels
  • Feed 8 QCA9-33 units to one QCA9-33 to combine up to 72 channels without signal loss
  • Feed combined output to a launch amplifier for larger systems
  • Mount separately from next-gen QMODs, unit will block airflow


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