User's Manual Part 2

RBS 2308 and RBS 2309 User’s Guide
See figure in this chapter for feeders and jumpers
mentioned in the example.
The frequency band is GSM 900.
The feeder length has been measured at 40 m.
1. Cables used:
RBS jumper (A):
Andrew 3/8-in. LDF2
Length: 2 m
The attenuation is 0.110 dB/m.
See the table in this chapter.
Total cable attenuation for the RBS jumper:
2 x 0.110 = 0.22 dB
Feeder (B):
Andrew 1/2-in. LDF4
Length: 40 m
The attenuation is 0.069 dB/m.
See the table in this chapter.
Total cable attenuation for the antenna feeder:
40 x 0.069 = 2.76 dB
2. Total attenuation:
0.22 + 2.76 = 2.98 dB
3. Enter the results in the test record.
Example 2 Calculating the Total Feeder Attenuation
6.6 Calculating the Feeder Delay
This s ection describes how to calculate the total delay in the feeder system.
1. Use the feeder length measured in Section 6.3.3 Measuring Feeder Length
on page 96.
2. Find the delay value (ns/m) for the cable type in Table 21 on page 100.
Calculate the total attenuation for each feeder and jumper, by multiplying
the length in metres with the delay per metre.
3. Add the delay for the feeder and the jumpers.
4. Enter the result of the calculation in the test record.
5. Calculate the feeder delay for all antenna feeders.
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/LZT 720 0027 Uen R8A 2006-06-27