Tempo Fitness Cable Scout TV90, Operating Manual

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Time-Domain Reflectometer Principles
A Time-Domain Reflectometer (TDR) is a device using a principle similar to
radar to measure time and distance over a length of cable. A TDR sends out a
pulse of energy and measures the reflections to events along the length of the
cable. The TDR measures the time taken for the reflections to return and con -
verts this into distance along the cable. The results are shown on the screen.
The events that a TDR can detect are normal occurrences such as Taps,
Splitters, Couplers, Loop Extenders, etc., as well as accurately pinpointing
trouble such as Shorts and Opens. A TDR can also provide a rough estimate of
the total amount of cable that is wet, and the exact location of the wet section.
The TDR displays a graph of the tested cable with distance (time to reflection)
on the horizontal axis. The on-screen cursor helps by displaying feet or meters
to a point on the cable. The vertical axis on the TDR display shows the type
and severity of fault. Several kinds of problems, as well as normal occur-
rences, are demonstrated in the next sections of this manual.
Typical TDR Display
Marker
Fault or Normal
Occurrence
Initial Pulse
(Instrument)