Mocomtech CRS-300 - Manual (Page 140)

CRS-300 1:10 Redundancy Switch Revision 16
Cables and Connections MN/CRS300.IOM
4–80
4.11 IF Cable Connections
There are two different possible IF configurations: single transponder and multiple transponders.
1. For a single transponder, all the modems are connected to the same user Up/Downconverter.
2. For multiple transponders, the modems may be grouped and connected in various
combinations to multiple up/down converters. The CRS-280 (70/140 MHz) IF Switch is
required for multiple transponder operation.
If using the CRS-280L (L-Band) IF Switch, additional installation information can be
found in the CRS-280L Installation and Operation Manual.
Proceed with the transponder configuration method applicable to your system.
4.11.1 IF Cable Connections – Single Transponder (without CRS-280/280L)
IMPORTANT
To prevent problems resulting from impedance mismatch, ensure that the
impedance for the modem’s cables and combiner are the same.
Referring to Figure 4-36 (L-Band operation shown):
For single transponder IF configurations, connect the user-provided IF cables as follows:
► For Transmit (Tx) IF Connections:
• Connect the appropriate user-provided IF cables from each modem’s “Tx IF” connector
(BNC for 70/140 MHz, Type ‘N’ for L-Band) to a single user-provided power combiner.
• Connect the output of the power combiner to the user Upconverter.
► For Receive (Rx) IF Connections:
• Connect the appropriate user-provided cables from each modem’s “Rx IF” connector
(BNC for 70/140 MHz, Type ‘N’ for L-Band) to the output ports of a single user-
provided splitter.
• Connect the input of the splitter to the output of the user Downconverter.
When a modem is taken offline, its Tx IF is automatically muted (shut down) by the CRS-300.