Operating Instructions
1502C MTDR User Manual 1–15
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ac 20.000 ft
Short
Figure 1–9: Short in the Cable
When the entire cable is displayed, you can tell if there is an open or a short.
Essentially, a large downward pulse indicates a short (see Figure 1–9), while a
large upward pulse indicates an open (see Figure 1–10). Less catastrophic faults
can be seen as smaller reflections. Bends and kinks, frays, water, and interweav-
ing all have distinctive signatures.
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ac 20.000 ft
Open
Figure 1–10: Open in the Cable
3. To find the distance to the fault or end of the cable, turn the
n
o
POSITION
control until the cursor rests on the leading edge of the rising or falling
reflected pulse (see Figure 1–10). Read the distance in the distance window
in the upper right corner of the display.
A more thorough inspection might be required. This example uses a longer
cable:
4. When inspecting a 452-foot cable, a setting of 50 ft/div allows a relatively
fast inspection. If needed, turn VERT SCALE to increase the gain. The
higher the gain, the smaller the faults that can be detected. If noise increases,
increase the NOISE FILTER setting.