Comtech EF Data KPA - Manual (Page 90)

KPA Ku-Band Indoor Solid-State Power Amplifier Revision 1
Appendix B MN/KPA.IOM
B–4
B.3.1 Redundancy Kit Control Cabling
For either a 1:1 or a 1:2 redundant system, two control cable assemblies are required for setup as
shown in Figure B-3. Other RF coaxial cables and waveguides are required as shown in Figure B-4.
Figure B-3. KPA Redundancy System – Control Cabling Schematics
The redundant loop cable used for interconnection of the KPAs via their J4 REDUNDANT
LOOP connectors, as shown in Figure B-3 and Figure B-4, has the following characteristics:
• The cable assembly is not a “straight through” cable.
• The cable assembly is labeled “BACKUP” on one end, and “KPA#1” on the other end.
• The cable assembly is wired so that, when connected to two KPAs, one KPA will
automatically configure itself as the Backup Controller and the other KPA will automatically
configure itself as the ‘Primary KPA’.
• The backup KPA communicates to the primary KPA via a serial interface that is also
provided by this cable assembly. This interface is used by the Backup KPA to acquire
configuration information from KPA #1. This interface additionally provides the link for
virtual addressing as described in this manual in Appendix C. REMOTE CONTROL.
• Also included in this cable assembly are summary fault relay contacts that are used by the
backup KPA as an input to its switching logic.
For 1:2 redundancy systems, note that the functionality described for the 1:1 cable assembly also
applies to the 1:2 cable assembly; the only difference is that there is now a third connector, labeled
“KPA#2”, daisy-chained onto the cable assembly. When a third Comtech EF Data KPA is
connected via this cable assembly, it will automatically configure itself as ‘Primary KPA #2.’
A second cable assembly – a six-wire assembly – connects the Backup Unit’s J7 RF SWITCH
connector to the Waveguide Switch.
1:1 System Control Cabling 1:2 System Control Cabling