L-25 Cellcomm's Amplifier

Discussion in 'Wireless & RF Design' started by Masud, Jul 8, 2010.

  1. Masud

    Thread Starter New Member

    Oct 4, 2009
    Dear Experts,I'M BADLY IN NEED OF YOUR SUGGESTION ON BELOW QUERY:I'm working in a GSM operator in Bangladesh.we are trying to share an IBS network of one local operator in a 8 storied building.Our BTS Output Power 33 dBm with two TRX (Ericsson Micro BTS)Other operator's BTS O/p Power 46 dBm (Siemens).Cable coming from Both BTS injected into a Hybrid coupler.Then one o/p of the coupler is terminated by a 50 ohm load and another cable goes to the 3 way splitter located at 6th floor.we placed a L-25 Line Amplifier before the splitter.the amplifier run by 220v ac supply.The I/P of the amplifier should not be more than 10 dB.Now........... at the I/p of amplifier, there are 2 signals of two different operator within DCS 1800 band. But the power level is not equal.we manually calculate the power of our signal is around 17 dB and the other operator signal's power is 30 dB.But the I/p should be within 10 db.so........ to reduce the i/p power, we placed few couplers in series (15 DB+10 DB) before the i/p of amplifier to make it less than 10 DB.The other ports of the couplers were terminated by dummly load.We were concern about the power level of other operator's signal...while the power level of our signal also goes very down due to the addition of couplers.Now...after doing the above things...we measure the O/P power of amplifier was 41 dB....But when we go for walk test by using the tools in different places of the 6th floor, there we found the Rx-Level of both operator's signal goes very poor comparing with the level we got earlier without adding the amplifier.The Rx-Level was very poor and inside the IBS locations, outdoor macro sites were working as the server there.PLEASE HELP ME TO FIND OUT THE REASON.WHY IT HAPPENED THOUGH WE MEASURE THE O/P OF AMPLIFIER WAS 41 DB WHICH GOES TO THE SPLITTER AND FROM THAT SPLITTER TO THE DISTRIBUTED ANTENNA SYSTEMS.UNFORTUNATELY WE DONT HAVE ANY MANUAL OF THAT AMPLIFIER ALSO NOT AVAILABLE IN THE NET OR IN CELLCOMM'S SITE....................THANKS IN ADVANCE
    Last edited: Jul 8, 2010