imbalance signal strength (NO VSWR ALARM)Causing high drop [Archive]

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wael

2011-08-22, 01:21 AM

Dears
we have issue imbalance signal strength(NO VSWR alarm) even after check the feeder and jumber we didnt face any issue (No cross feeder and NO VSWR )

the cell have Single BCCH the underlaid GSM 900 and overlaid is DCS1800

the imbalance signal strength is on the Sector A &C in the DCS1800 GRFU only .

pls advise

Justradio

2011-08-22, 01:39 AM

how u perform the VSWR check?

wael

2011-08-22, 01:43 AM

i dont know , this was a feedback from FM eng .

Justradio

2011-08-22, 01:59 AM

please refer the below link. hope it help u.

http://www.finetopix.com/live-optimization/12217-rx-path-imbalance.html

tremalnike

2011-08-22, 02:01 AM

May be a different antenna vertical pattern ? What's the antenna's type ? If this is the reason it can be solved with different tilts

wael

2011-08-22, 02:12 AM

please refer the below link. hope it help u.

http://www.finetopix.com/live-optimization/12217-rx-path-imbalance.html

the imbalance signal strength stats showing the problem in the TX path not RX !!!!

callme_eez

2011-08-22, 02:25 PM

Which equipment ?

If Huawei please try to check BTS Power output. Also check RF Send and Receive Mode on every TRX and make sure the configuration is matched with requirement.

wael

2011-08-23, 01:54 AM

Which equipment ?

If Huawei please try to check BTS Power output. Also check RF Send and Receive Mode on every TRX and make sure the configuration is matched with requirement.

Thanks the BTS is BTS3900L and send mode =DTIC and receive mode=MAINDIVERSITY ,board is GRFU 4Trx and the Power level is 0 and power type is 20 watt

I did not fine the setting of the Send and Receive Mode in doc for this kind of BTS &GRFU

could you pls provide me with setting

cougsnoopy

2011-08-23, 02:45 AM

Multiple Items with the assumption of correct datafill that I've come across:

1. Bad connectors (Not Tight or cross threaded)
2. Cables within the cabinet between the radios and PAs are faulty or even mismatched for a different frequency band
3. Cut Lines/Missing Antenna (Don't ask how those happen but they do)
4. Bad PAs (Don't always alarm)
5. Power Issues with BTS (Although This typically alarms)
6. TMA Issues (Although someone said this was a DL, not UL issue although I didn't see the actual imbalance measurement)

So basically what we go through is the sanity checks of the parameters, sweeps going out of the cabinet, then checking cables and connectors going backwards in the cabinet.

faisalusuf

2011-08-23, 03:04 AM