Cable Measurements
R&S FSH
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Calling the function:
Press the MEAS key.
Press the MEASURE softkey.
The measurement function submenu opens.
Using the cursor keys or the rotary knob, select the
DISTANCE TO FAULT menu item and confirm
your selection with the ENTER key or the MEAS
softkey.
The R&S FSH turns on the "Distance To Fault"
measurement function.
Cable type
DTF status
Cable length
Softkey menu for
DTF measurement
Connected VSWR
bridge
To perform distance-to-fault measurements, the R&S FSH needs to “know” the type of cable and its
approximate length.
The cable type must be known to determine the speed of propagation and so the distance to any fault
along the cable. The attenuation of the cable must be known to determine the size of the fault correctly.
The R&S FSH automatically sets the span according to the approximate length of the cable.
Cable selection
Frequency-dependent cable models can be generated with the supplied R&S FSH View Windows
software package and loaded into the R&S FSH. The procedure is described in the R&S FSH View
manual. The R&S FSH can store up to 100 different cable types in its internal memory. The total
number of storable limit lines, transducer factors and cable models is 100. If transducer factors, channel
tables, limit lines or data sets are stored simultaneously, the maximum number of cable models
decreases correspondingly (see "Saving and Loading Instrument Settings and Measurement Results" in
this chapter).
Frequency-dependent cable models can also be defined directly on the R&S FSH in the corresponding
menu. In this way, cable models not generated with R&S FSH View can be added.
If the distance to a cable fault is to be located precisely, it is essential to use the appropriate cable
model. If not, the R&S FSH will not be able to correctly determine the distance of the fault from the
measurement plane and the magnitude of the reflection at the fault.
