Contemporary Research QDA4-45 RF - Manual (Page 5)

Contemporary Research 5 QDA4-45
Installation
Basic Setup
The QDA-4-45 is designed for QMOD applications, but can be used with other RF channels at similar levels.
Use only the included 12 VDC power supply, do not use with shared 4 or 6 amp DC power
supplies.
Connect one source to Input 1
 Connect to the In 1 RF Input (not 2-3)
 Select Input 1 on the front panel
 Adjust Gain up and down, 0 – 32 dB, add in input level for total RF level. For example to amplify one
QMOD (typical 29 db) to 45 dB, add +16 dB of gain. For amplifying QCA9-33 Active Combiners that
are fed from QMODs (typical 32 dB), add +13 dB for a 45 dB level output.
Connect up to four sources to Inputs 1-4
 Connect to the Inputs 1-4
 Select All on the front panel
 Adjust Gain up and down, 0 – 25 dB, add in input level for total RF level. The gain setting
compensates for the 7 dB loss in the combiner, so you just add the gain setting to the input level.
For example to amplify four QMODs (typical 29 db) to 45 dB, add +16 dB of gain.
RF Amp Out
The QCA9-33 accepts up to 38 dBmV RF level, and you can amplify up to +50 dB.
RF Levels
If the RF level is too strong, the TVs can act as if there is no RF signal.
 The input RF level and the QDA gain level should not exceed 50 dBmV; the goal is to average about
45 dBmV or less. If the total gain is too strong, the amplifier can be overloaded, which could appear
as No Signal to TVs.
o If you’re combining one to four QMODs, the gain should be no more than 16-20 dB
o If you’re combining one to four QCA9-33s, the gain should be no more than 13-17 dB
 The RF level at the TVs should be about 0 to 20 dBmV. Digital RF channels are very flexible, and
we’ve found that some TVs can receive the channel at about 29 dB. However, if the RF level to TVs is
too high, the TVs can respond as if there is no signal.
2-Way Operation
The QD4-45 is not designed for 2-way operation, but that could be performed using 2 sub-channel diplexers.