Contemporary Research SW-DX Integration Guide - Manual (Page 3)

Contemporary Research 3 iC-Net Tips – RF Design and Installation
Step Two
– Install ICC Head End
The ICC-HE or ICE-HE Head End will receive the RS-232 or Telnet commands from the
software and translate them to a small RF channel that runs between channels 4 and 5. It
also sends out a test command every second. The display installers can use this “pulse”
feature to confirm that the controller is “on the network”.
A common error for first-time installers is to attach the main cable feed to the RF In on the
Head End and attach the other end of the feed into RF Out. Nope. The RF In is for special 2-
way control signals. You use an external combiner to mix the control channel with the other
channels.
The key step in this part is to insert the RF Out of the Head End into the RF cable system.
Generally, you’ll use a combiner or splitter to combine the control channel with the main RF
feed. To do so, you want the control channel set to about the same strength as the RF
system. The Head End broadcasts at 50 dB, and includes a couple filters to knock that down
when needed.
The best technique is to use an RF meter to measure the main feed’s level, then match the
output of the Head End. The blunt approach would be to combine the Head End, then look
at how it affects other channels. If the other channels are affected, drop in a 20 dB
attenuator.
In other sites, you’ll be mixing the output of the Head End with other sources into and RF
Combiner, then amplifying the total output to the main system. Again, all the sources need
to be combined at approximately the same RF level. The best way is to use an RF meter to
measure all the sources to match. Generally, digital channels are set about 6 dB less than
analog channels. Measure the control channel as an analog channel.
Typical outputs are
RF Modulator – 45-55 dBmV
Cable Feed – 15 dBmV
Head End – 50 dBmv
QMOD Modulator – 29 dBmV