22
Chapter 3
Making Measurements
Making Return Loss Measurements
Making Return Loss Measurements
Purpose
Some of the energy incident upon a device can be reflected back towards the
source. A return loss measurement quantifies this reflected energy. Return loss is
used to determine the health of an antenna system and its associated cabling by
measuring the amount of transmitted power reflected back from the antenna
system and therefore not passed over the air interface to the mobile user.
Cables and antennae are often subjected to harsh weather conditions resulting in a
performance which deteriorates over time, leading to an eventual failure. By
monitoring return loss over time, cable and antennae performance can be
monitored and preventive action taken when required.
Making the measurement
A return loss measurement requires the use of a signal separation device such as a
directional coupler or bridge in addition to the device being tested for return loss.
The spectrum analyzer must be in spectrum analyzer mode for this measurement.
Procedure
For the following procedure, use the appropriate 50 ohm or 75 ohm cables and
accessories listed in
1. Connect the tracking generator, signal separation device, device being
measured and the spectrum analyzer input as shown in
Table 3-2
Cables and Accessories
Cable/Accessory
Quantity
50 Ohm Setup
Part Number
75 Ohm Setup
Part Number
Coaxial cable
2
8121-0101
5062-6452
RF Bridge
1
86205A
86207A
Coaxial load
1
909A Option 012
909E
Coaxial short (50 ohm only)
1
11512A
n/a
6 dB Attenuator (50 ohm only)
2
0955-0826
n/a
Adapter 75 ohm N(f) to
75 ohm BNC(f) (75 ohm only)
2
n/a
1250-1536
Summary of Contents for ESA-E Series
Page 4: ...iv ...
Page 6: ...vi Contents ...
Page 7: ...1 1 Getting Started This chapter describes the process for installing the personality ...
Page 14: ...8 Chapter1 Getting Started Installing the Optional Measurement Personality ...
Page 16: ...10 Chapter2 Menu Maps and Key Descriptions Menus Menus Mode and Measure Menus ...
Page 21: ...15 3 Making Measurements ...
Page 44: ...38 Chapter4 If You Have a Problem Before You Call Agilent Technologies ...
Page 46: ...Index 2 Index ...