Technical data

Chapter 10 285
Distance to Fault
Measuring Distance to Fault
Distance to Fault
20 For Custom Cables
only (Cable
Type =
Cust), you must
specify the
characteristics of your
cable. Use [Cable
Atten] and [Prop Vel] to
do this.
Specify your custom cable’s attenuation [Cable
Atten.] in dB per 100 m (or in dB per 100 ft.)
Specify also your custom cable’s propagation
velocity [Prop Vel], measured as a percentage of
the speed of light in a vacuum.
The values you enter here will be used for the
measurement, and will be displayed at the upper
left of the display.
Most cable manufacturers provide a table showing
attenuation versus frequency for each type of cable.
Remember that attenuation varies with frequency,
so select an attenuation value that corresponds as
closely as possible to the center of the frequency
range you are using.
21 Check whether your
analyzer has already
been calibrated over the
frequency range and
with the correct cable
type that you wish to
measure. If it is already
calibrated over the
correct frequency range
and cable type, you can
omit the next steps
(Step 22 and Step 23)
and go straight to Step
24.
The analyzer displays its calibration status on the
top left of the measurement screen. You only need
to re calibrate if you:
• power off the test set
• change the start frequency to a new value that
lies below the start frequency of your previous
calibration
• change the stop frequency to a new value that
lies above the stop frequency of your previous
calibration
• change any of the jumper leads that you used
for the calibration
• change any of the attenuators that you used for
the calibration
• change the type of cable specified under the
[Cable Type] menu key.
For more information, see “Calibration -
Minimizing your Workload” on page 281.
Step Notes