[Hamanta Mech]

How can I cease the rx divercity lost alarm.
( I had check the antenna to Bts feeder/jumper connections, replace the Tx-Rx cable. reinstall the IDB,but still the alarm exist. )

[oleg]

to aman
tell me why the diversity alarms are arrise in two sectors…

u probably have X-connection of RX feeders between two sectors.

[OLeg]

Fault name RX diversity lost
Description The imbalance in signal strength between the receiver A- and B-side is
supervised on a TRU basis. The fault arises when one or several TRUs have
reported a signal strength imbalance of at least 12 dB during 50 minutes.
This indicates that an RX path to one or several TRUs is faulty. The
receiver sensitivity for these TRUs is reduced by about 3.5 dB. Note: This
fault is not raised if one of the faults SO CF I2A:7 (RXDA), SO CF I2A:11
(TMA current), SO CF I2A:34 (TMA voltage) or SO CF I2A:39 (RX cable)
is active.
Action Enable the diversity supervision monitor in OMT for each TRU, to find out
which TRUs are affected and which side (A or B) is faulty. The diversity
supervision measurements are only taken every 5 minutes so it takes some
time to notice changes. The measurements give signal strength imbalance
(SSI, expressed in dB) on each TS. The SSI is equal to RX signal A-side
minus B-side so positive values indicate that A-side is better and vice-versa.
Check that all cables on RX-path are properly connected (including HLin/
HLout). Also check the antennas. If several cells are affected then maybe
two RX feeders have been switched. If only one TRU is affected, then
check RX cable between TRU and CDU. Try moving TRUs, CDUs and
cables in the cabinet to see if the fault follows the unit(s).

[michael]

i had an alar in a 2106 ericsson rbs or rx path lost on b reciver side and i already change the feeders jumper cables antenna and cdu rf conectorrs an the alarm goes off and after a coople hours comes back can somebody help me

[Oleg]

To Michael:

The fault arises when one or several TRUs have
reported a signal strength imbalance of at least 12 dB during 50 minutes.

Use OMT/Maitenance/monitor/Diversity supervision meas/… check all TRUs (You should wait 5-10 min during monitoring). Select TRU with worse SSI(Side A-B), try to exchenge DTRU betwin cells, perfom monitoring again, if fault (bad SSI)goes with DTRU – install a new one, ather case – try to replase CXU. Monitor again.

[prince]

Frequency interference can also cause Rx diversity alarms so please check your frequencies.

[Bijoy]

Hi Prince
Please elaborate how this could happen??I’m really curious!!!

Br\\
Bijoy

[Jim]

Does Anyone if you can set up 2106 BTS with LNAs without the use of the TMA Card?

[hari]

I need to know the value rx path imbalance.the value is in between 12 to -12 db or else only +ve values or -ve values

[Ratan Deep]

Is DRU faulty may lead to
VSWR.

[abdul nkrumbih]

I get the rx diversity lost on B receiver side when TMA is activated in rbs 2106
How can I go about to solve the problem.Please help.

Again when calling from the site,called part can hear me but I cant hear fro him.

[Rex]

Hi Abdul,
in cases when you can’t hear called party the problem is his Uplink. Check connections with TMA whether they are wrong connected or change TMA.
Regards,
Rex

[abdul nkrumbih]

What is the problem actuaaly,some sites have rx diversity lost but still people communicate while in othersites it is vice versa.
Can anyone clearly elaborate more?

[Jason]

Hi All;
I seem to be having a similar issue with the ‘RX path imbalance’ alarm. I need some assistance also. I don’t believe that this is a hardware issue because it seems to be randomly coming and going on our 2106 sites.

My First thought:
I am wondering if we have a parameter problem. Defining this alarm I can adjust:
Class 1 Alarm(dB): mine is set to “Off”
Class 2 Alarm(dB): mine is set to 6.0 the default
Supervision Window Time(minutes): mine is set to 1440 the default
Minimum Number of Samples: mine is set to 7000 the default.

I know if I set the Class 2 Fault Limit to “Off” I will get rid of the alarm, but that will not solve anything.

So I have thought about tuning these parms, but I am not sure where to start with these.

Second Thought:
In the RBS OMT I have the ability to “Define the loss” Currently we have no TMA’s and our value for this is set to “0”. The documentation I found on this said we should set this to “0” for non-tma configurations.

Please help with any thoughts or ideas. Thanks.

[abdul nkrumbih]

I have noted the following scenario:
One leg was affected by VSWR and thus cause one dtru to be out of service.

After measurement of distance to fault using site master i found there was water inside the polyphaser connected between feeder and jumper.

However i was not able to dry he polyphaser due to its shape,thus i decided to bypass the polyphaser.
when that is done you also get the rx diversity lost on that dtru.
when the plyphaser is reconnected the diversity alarm disappears.
We may start frm there to re-establish a complete sln towards the diversity lost alarms.
Any one can volunteer

[Author]

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