Users Manual

MDS 05-6399A01, Rev. G MDS™ Master Station 119
6.7 Duplexer Tray
Current Master Station offerings always include a Duplexer tray whether or not an internal du-
plexer is included. The duplexer tray is cabled to the Alarm Relay Module, in a redundant unit,
or to the Radio Module if non-redundant. This is cabled on the front of the master station from
TX to RF-1 and from RX to RF-2. The cabling inside of the duplexer tray is dependent on the
frequency plan, whether transmit or receive is on the higher frequency. If the master station was
ordered with an internal duplexer and the user is changing from transmit high to transmit low, or
vise versa, the cabling inside the duplexer tray may need to be modified.
For master stations ordered before January 2017, the cabling to the duplexer depends on the fre-
quency plan. In this case, the duplexer tray will be labeled HIGH and LOW. For those units, ca-
ble as directed in Table 6-23 below.
Table 6-23. Cabling to the Duplexer Tray Faceplate for pre-2017 Master Stations
Duplexer
Option
Frequency
Plan
Cable
From - To
Antenna Connection
on Back
Comment
Internal TX > RX TX - HIGH
RX - LOW
COMBINED OUT Cable by Frequency Plan to High/Low
Internal TX < RX TX - LOW
RX - HIGH
COMBINED OUT Cable by Frequency Plan to High/Low
Simplex TX > RX
TX = RX
TX < RX
TX - HIGH
RX - LOW
TX
RX
Software configurable single or dual
antenna port.
External TX > RX
TX < RX
TX - HIGH
RX - LOW
TX
RX
Wire TX to High always, independent
of Frequencies
Table 6-24. Duplexer RF Performance
Duplexer Type
Frequency
Loss (dB) +/
-
0.1 dB
No Duplexer
400 MHz 0.35
700 MHz 0.55
900 MHz 0.75
Notch Duplexer
400 MHz 1.20
Bandpass Duplexer
700 MHz 1.50
900 MHz (9MHz Split) 2.10
900 MHz (24 MHz Split) 1.50