User's Manual Part 2

RBS 2109 User’s Guide
Table 14 Velocity Factor and Attenuation for Different Cables
Attenuation, dB/m (CABLE LOSS)
Feeder Type
Andrew
Velocity
Factor
(PROP
VEL)
GSM 800 GSM 1900
7/8” LDF5
0.89 0.037 0.060
1 1/4” LDF6
0.89 0.027 0.043
1 5/8” LDF7
0.88 0.022 0.036
Note: If the cable type is not found in the table above, the values must be
taken from the manufacturer’s specifications.
6.3 Performing DTF Tests
The purpose of the Distance To Fault (DTF) test is to verify that there are no
bad connections or other faults (for example sharp bends) in the feeder system.
This test also measures the length of the feeder system to be used in the feeder
attenuation calculation.
It is recommended to perform the DTF tests during the installation phase,
before the antennas and TMAs are connected.
6.3.1 Connecting DTF Test Setup
This section contains test setups and information about how to connect the test
equipment for the DTF tests. The test setups are described for the following
antenna systems:
• Passive antenna systems (no TMA)
• Antenna systems with ddTMA
Connecting Test Setup for Passive Antenna Systems (No TMA)
This section describes how to connect the DTF test setup for passive antenna
systems (without TMA).
1. Connect the 50
standard load to the antenna jumper. See figure below.
2. Connect the test equipment to the RBS jumper. See figure below.
79EN/LZT 720 0090 Uen R1A 2004-09-17