Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner

Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner

Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner

B&H # COQDA445 MFR # 5092-001
Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner

Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner

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  • 1Description

The Contemporary Research QDA4-45 is an amplified RF combiner that can switch between one or four inputs, with adjustable amplification up to 50 dBmV. You can add up to 32 dBmV gain for one input, and 25 dB for four inputs. Designed for QMOD HDTV applications, the unit 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. This compact unit mounts two-across in a single rack space using CR RK1 and RK-2 rack kits (available separately), and can be mixed with QMOD HDTV modulators using the same rack kits.


  • QMOD HDTV modulators
  • QCA9-33 active combiner

Product Highlights

  • Switches between one input or four input combiner
  • Adds up to 32 dBmV gain for one input, 25 dB for four inputs
  • Adjusts RF gain from front-panel controls and LCD display
  • Provides a maximum output level of up to 50 dBmV
  • Wideband, low-noise amplifier
  • Low power, draws less than 8.5W
  • Compact metal enclosure, mounts 2 across in 1 RU using RK1 and RK2 rack kits (available separately)
  • Made in USA


  • Use the QDA4-45 as a 4-channel, 45 dB amplifier for larger RF applications
  • Combine up to four QMOD modulators
  • Combine four QCA9-33 active combiners for 36 channels
  • Use as launch amplifier for the RF system
  • Use as booster amplifier to merge QMOD channels with existing 50 dB analog modulator systems
In the Box
Contemporary Research QDA4-45 RF Distribution Amplifier & Combiner
  • PS12-1 1A 12 VDC Power Supply
  • Limited 2-Year Warranty
  • Table of Contents
    • 1Description
    Front Panel Input Selection: 1 or 4 inputs (green LED indicators)
    RF Gain Selection with LED Display: 0 to 25 dB for four inputs, 0 to 32 dB for one input
    Back Panel 4 x Input F connector
    1 x Amp out F connector
    1 x DC power input (2.1 mm coaxial jack, inside center conductor positive)
    Maximum Input 40 dBmV
    Isolation 38 dB typical, 30 dB minimum, 54 to 860 MHz
    Return Loss Input: 30 dB typical, 13 dB in single input mode
    Output: 17 dB typical
    Output Input 1: 0 to 32 dBmV gain, low noise, linear performance through 860 MHz
    All Inputs: 0 to 25 gain (7 dBmV loss from combiner)
    Maximum Output Level +50 dBmV
    Composite Triple Beat -60 dB, 134 channels at +44 dBmV per channel
    Noise Figure 4.5 typical
    LED Indicators 1 x Power LED 2 x Green LEDs for input selection
    Power Requirements 11.5 to 13 VDC, 12 VDC typical
    700 mA maximum
    Enclosure Durable metal enclosure, rack mountable
    Dimensions (W x H x D) 8.5 x 1.75 x 6.0" (216 x 44 x 153 mm)
    Weight 1.1 lb (500 g)

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