Contemporary Research

QDA4-45 RF Amp Combiner

QDA4 45 RF Amp Combiner

The Contemporary Research QDA4-45 is an amplified RF combiner that can switch between one or four inputs, with adjustable amplification up to 50 dB. 

Designed for QMOD HDTV applications, the QDA4-45 can receive an RF feed from QMOD modulators or QCA9-33 Active Combiners. Inputs can be switched between one or four inputs, with selectable gain. 
The compact QDA4-45 mounts two across in a single rack space using CR RK1 and RK2 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.


  • Switches between one input or four input combiner
  • Adds up to 32 dBmV gain for one input, 25 dB for 4 inputs
  • Front-panel gain adjustment and LCD level display
  • Provides a maximum output level of up to 50 dBmV
  • Wideband, low noise amplifier 
  • Low power, draws less than 8.5 watts
  • Compact metal enclosure, mounts 2 across in 1 RU using RK1 and RK2 rack kits


  • Combine up to 4 QMOD Modulators
  • Combine 4 QCA9-33 Active Combiners for 36 channels
  • Use as launch amp for RF system
  • Use as booster amp to merge QMOD channels with existing 50 dB analog modulator systems
  • Mount separately from QMOD modulators. Unit can block flow-through ventilation in new-generation QMODs


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