User's Manual

Code: D148X01PT_DDS06
MBS USER AND
INSTALLATION
MANUAL
Date: 19-Dec-2012 Page: 36 of 36
01.01.00/1 Rev.1
8. INCIDENTS
The MBS Unit must be repaired by authorized technical personnel only. There
will not be performed any repair of the MBS Unit and it will have to be sent to
factory except for the change of the pressure equalizer or the overvoltage
protections.
8.1. INTERFERENCE AT MBS UNIT
This alarm is monitored in the NEBULA (NMS) management and configuration module.
See the infrastructure event list (F067516) in NEBULA Technical Manual.
Any interference in the MBS Unit is activated when there are a large number of
consecutive invalid events in the MBS Unit. A reception fault is considered when a level
higher than the threshold for reception of the carrier, but is not recognized as a valid
signal. Depending on the signal level, interference is considered low or high. So, if the
level of signal is above the threshold for reception and below the threshold set to high
interference and is not recognized as a valid sign, it will be a low interference alarm. If the
signal level is above the threshold set to high interference and is not recognized as a valid
signal, the low level alarm would disappear (if it happened) and high interference would
produce.
These alarms are turned off with any valid signal reception for low interference case, and
with more than one consecutive right reception for high-level interference.
8.2. OVER VOLTAGE PROTECTION
The MBS Unit has several protections against lightning and surges, in any case the action
of these protections generate an alarm in the NMS client which disappear when the
protective element is replaced by authorized technical staff.
a) Protection against lightning and power surges
This protection is located within the MBS Unit. It should be changed every time it
breaks even if the MBS Unit continues functioning properly. An alarm in the NMS
Client is reported showing that the replacement of this type of protection is needed.
b) Protection against lightning and surges in the RF connections
This protection is located inside the connectors themselves (ANT and DIV_IN).
These connectors have a gas discharger that when it is broken, it ceases to
receive/transmit signal through the connector. The NMS Client provides a reflected
alarm when the ANT discharger fails and diversity alarm when the DIV_IN
discharger fails.