Issue Description
The configuration for this link is HSB 1+1 38 GHz
Equipment: RTN 950 equipment
Version: V100R001C00_02
NE: DMR054 - DMR163
Date: 2011-03-27.
Description: installation Microwave link but the RX level is not like customer design there is 3.2dB difference between site A and site B
Alarm Information
No alarms, just design mismatch.
Handling Process
I.Check the alignment again
II.Check the ODU received IF signal power level by use following command with Navigator: Refer to attachment for more information
III.Check the antenna polarization:
IV.Test the hardware parts:
1-First disconnect the protection ODU and the hybrid coupler in site A & B, in this case the link configuration is 1+0 after that we did the re alignment; we get the correct RSL.
2-I disconnect the main ODU and connect the protection ODU in site A & B, the link configuration is 1+0 after that we did the re alignment; we didn’t get the correct RSL.
3-Change the protection ODU in site A and keep the main ODU in site B; we didn’t get the correct RSL.
The RX level:
Site RX level TX Power
DAM-163 (A) -37.7 dbm 6 dbm
DAM-054 (B) -34.5 dbm 6 dbm
4-Change the main ODU in site A and keep the protection ODU in site B; we get the correct RSL.
The RX level:
Site Main RX level TX Power
DAM-163 (A) -34.7 dbm 6 dbm
DAM-054 (B) -34.5 dbm 6 dbm
In this case the sensitivity of one ODU in site A is more than default it’s about 4 dbm, the default value is + - 2 dbm
5-Re installs the hybrid coupler in both site and installs the main ODU’s; we get the correct RSL.
The RX level:
Site Main RX level Protection RX level TX Power
DAM-163 (A) -36.5 dbm -42.0 dbm 6dbm
DAM-054 (B) -36.3 dbm -41.8 dbm 6dbm
Root Cause
ODU sensitivity Problem
Suggestions
A.The sensitivity of one protection ODU is more than default value. it’s about 4 dbm, the default value is + - 2 dbm.
B.Before installation, it’s better to check all the equipment if it’s matched, and test it if it’s possible.
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