User's Manual
Doc. No.
Rev.
Date
DRAFT
1.01
2012-01-27
Damm Cellular Systems A/S, Denmark
TetraFlex
®
7.5 Manual - BS421 Configuration
TetraFlex® 7.5
Manual
2-72
2.6.4.1 Diversity configuration
Two TR421 may be used without the RF coaxial connection between them. In this case the
system will behave normally as a 2 carrier system, but will NOT support diversity.
When using diversity set-up (Standard configuration), the RF coaxial connection must be
installed and RX-B input (6dB pre gain) must be set
This configuration also applies to the 4 carrier configuration, where the carriers are defined as
two 2 carrier systems.
2.6.4.2 RX-B setting (Diversity) in TetraOM:
24 Display setting
24+ Select RX-B input Cascaded (Standard setting)
24- Deselect RX-B input Cascaded
NOTE: This must be configured in both BS421
2.6.4.3 3 And 4 carrier operation
NOTE: Operation with 3 and 4 carriers with redundant BSC require a change to the HW of
the BS421 and the SB421 (See the SB421 section for details) if the HW version stipulated on
the serial number label is v1.
HW version v2 and forth has the possibility to change the setting via the TetraOM program.
This change is required to ensure correct BSC handover and synchronization of the carriers
The change cannot be made in the field. The system must be ordered for 4 carrier operation
or the units may be returned to DAMM for modifications.
NOTE: For change in the field (trained staff only), please order a change kit from
DAMM This kit includes a manual dealing with this issue and the necessary
hardware, jumpers, screws, markings etc.
For a 4 carrier system, 2 of the BS421 is marked “MASTER” and 2 are marked “SLAVE”
One master and one slave are to be connected to each SB421, the master being TR1/TR3
and the slave TR2/TR4.
NOTE: A GPS antenna should at least be connected to TR1 and TR3
2.6.4.4 Synchronization
The TETRA Base Station TR's need to be time synchronized to operate correctly.
Most important, all TR's in a radio cell shall be time synchronized to ensure correct timing for
the mobiles, when switching from the control channel to a traffic channel on another TR.
For a multi-cell systems, all radio cells are also recommended to be time synchronized to
enable use of seamless handover (cell re-selection).