User's Manual Part 2

RBS 2109 User’s Guide
11. Click on Start Monitor and read the value of the cable attenuation. The
displayed value is given in deci dB (10 deci dB = 1 dB). Make a note of
the value in the test record.
12. Add the measured cable attenuation values. The value given by Lin Att
PCM A (C) is the cable attenuation to the previous RBS in the chain, so
the measured value must be added to the value for the previous RBS(s) to
obtain the total cable attenuation for the RBS in question.
13. Use the total cable attenuation value to find the long haul parameter value
for LBO A (C) in the table below.
Table 41 Long Haul Parameters for Different Maximum Input Signal Levels
Long Haul Parameters for Different Maximum Input
Signal Levels at the Far End
Cable
Attenuation (dB)
0 dB -7.5 dB -15 dB -22.5 dB
0 – 7.5
0
-7.5
-15 -22.5
7.5 – 15
0 0
-7.5
-15
15 – 22.5
0 0 0
-7.5
> 22.5
0 0 0 0
14. If there is another RBS in the chain, then set LBO B (D) to ‘‘Long h., 0
dB’’. Used B (D) ports in multidrop configurations should always be set
to ‘‘Long h., 0 dB’’.
If this is the last RBS in the chain, then set LBO B (D) to ‘‘Short h., 0 – 133
feet’’. Unused ports are always set to ‘‘Short h., 0 – 133 feet’’.
15. If there is another RBS in the chain, then repeat steps 7 to 14.
Example of an Automatic LBO Parameters Calculation for Long Haul
P010474A
Far End
RBS 2
A C B D
RBS 3
A C B D
RBS 1
A C B D
Measured cable
attenuation =
9 dB
Measured cable
attenuation =
3 dB
Measured cable
attenuation =
5 dB
Maximum
input signal
level=
-15 dB
Figure 64 Calculating LBO Parameters Automatically for Long Haul
131EN/LZT 720 0090 Uen R1A 2004-09-17