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Chapter 15
Using Cable and Antenna Analyzer
JD700B Series User’s Guide
531
Performing reflection measurements
The Reflection measurement can be used to characterize cable and antenna system to ensure transmission
line impedance performance and signal reflection characteristics of cell-site across a specific frequency
range in voltage standing-wave ration (VSWR) or return loss.
Making a measurement
Procedure
1
Make a proper cable connection as described in “Connecting a cable for reflection, DTF, 1-port
phase, and Smith Chart measurements” on page 528.
2
Press the
MEASURE SETUP
hot key.
3
Press the
Data Points
soft key to change the resolution of your measurement, and then select
the data point option:
126
,
251
,
501
,
1001
, and
2001
. Changing the data point does not affect
current calibration.
NOTE
The larger number you choose, the higher resolution you get and the longer the
instrument takes to sweep and display results. Selecting the data point larger than what
you need for a measurement will result in unnecessarily long sweep time. It is
recommended that you select high resolution data points only for an instance of
measuring wide frequency bands or requiring precise measurement data.
4
Optional
. To turn the bias tee on, complete the following steps:
Toggle the
Bias Tee
soft key and select
On
.
Enter a value between 12 and 32 with 0.1 V step, and then press the
V
soft key.
NOTE
The instrument’s built-in bias tee function (option 002) supplies 12-32 VDC bias to active
devices through the
RF In
port, eliminating the need of an external power supply.
5
Optional
. To select the output power, toggle the
Output Power
soft key between
0 dBm
and
-30 dBm
.
NOTE
When an amplifier’s reflection is measured, it is recommended that you change this
output power level to -30 dBm and then re-calibrate. Changing to -30 dBm may result in
reduced measurement dynamic range.
6
Optional
. To turn the interference rejection on, toggle the
Interference Rej
soft key between
On
and
Off
to enable or disable the feature.
NOTE
It is recommended that you use this feature only when you suspect interfering signals in
the area as turning this on slows down the measurement.