S820E UG PN: 10580-00343 Rev. H 3-11
Cable and Antenna Measurements 3-5 Distance-To-Fault (DTF)
Transmission Line Selection
The Microwave Site Master 820E is capable of measuring either coaxial cable
or waveguide feeder lines. Selecting the correct coaxial or waveguide type is
critical for accurate DTF measurements. Incorrect propagation velocity (or
Cut Off Frequency in the case of waveguide) values affect the distance
accuracy, and inaccurate attenuation values affect the accuracy of the
amplitude values.
Selecting the line type or creating a custom type is described in the following
sections.
Cable List
The Microwave Site Master S820E is equipped with a built-in, predefined
cable list (Freq/Dist > DTF Setup > Cable List), which includes most of the
common cables that are currently in use. After the correct cable has been
selected, the instrument updates the propagation velocity and the cable
attenuation values to correspond with the cable. For setups with several
different cables types, choose the main feeder cable.
For cables not on the list, select NONE and manually enter the Prop Velocity
and Cable Loss in DTF Aid or the DTF Setup submenu.
Custom Cables can be created and uploaded to the instrument by using Line
Sweep Tools (LST). Instructions for using the LST Cable Editor are available
in the LST software Help menu. The latest version of LST is available from
the Anritsu web site: http://www.anritsu.com/.
The name, propagation velocity, and cable loss of the selected cable is
displayed below the graph during distance measurements (Measurement >
DTF Return Loss or DTF VSWR) as shown in (Figure 3-6).
Note
If the Cable list button is not displaying, then toggle
DUT Line Type to Coax
Note
Custom cable settings that are entered manually are not saved
when the instrument is preset, reset, or turned Off.
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