Fluke DTX-1800 Technical Reference Handbook page 281

Table 10-3.
Large reflective event with high loss (top) or excessive tailing (bottom). May be identified as an
end event though it occurs before the end of the cabling. May be caused by the following:
•
A dirty, scratched, cracked, misaligned, or unseated connector. Misaligned or unseated
connectors can also cause large reflections that produce ghosts. Bad connectors should be
cleaned, repolished, or replaced.
•
A good connector with a sharp bend or crack within its deadzone. If the cable is tightly bent
the tester may indicate a break, especially at longer wavelengths or in Manual OTDR mode
with smaller resolution settings. Use a visual fault locator to precisely locate the fault.
•
A crack in the fiber. Use a visual fault locator to precisely locate the fault.
•
A connection between mismatched fibers (different backscatter coefficients, core sizes,
numerical apertures, or other parameters). The top example could be caused by a larger core
(on the left) connected to a smaller core.
amd160.eps
Diagnosing OTDR Test Failures (cont.)
Diagnosing Fiber Cabling Faults
Diagnosing OTDR Test Failures
10
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10-7