Versiv Series Cabling Certification Product Family
Technical Reference Handbook
436
Ghost Source
A reflective event that
causes an ghost.
Caused by a dirty or unseated connector, a
connector with solvent on its endface, a
highly-reflective connector, a connector with
the wrong polish, a sharp bend, or a crack in a
fiber.
On traces with multiple ghosts, the event table
possibly shows only the strongest ghost source.
You can usually see that other reflections are
ghosts because they occur at multiples of
distances to connectors and they show almost
no loss.
Verify that the connector is seated properly.
Inspect connectors that cause ghosts. If a
connector is apparently not the ghost source,
use a visual fault locator to look for bends or
cracks in the fiber near the ghost source.
Gainer
An apparent gain in the
strength of the returned
signal. A gainer shows as a
negative value of loss.
Page 501 shows OTDR
traces gainers.
Caused by a splice or connection between two
fibers that have different backscatter
coefficients, numerical apertures, core
diameters, or mode field diameters.
The tester compares the loss of non-reflective
gainers to the limits for splice loss to give the
event a PASS/FAIL status.
If a gainer occurs at a connection, the gainer
shows as a Reflection event with negative loss.
The tester compares reflective gainers to the
limits for reflective events to give the event a
PASS/FAIL status.
Strong reflections at or before an event can
cause tailing after the event, which can cause
a measurement of negative loss.
To find the cause of a gainer, see if the fiber
type is different before and after the splice or
connection. Replace fiber if necessary. Fibers
that are the same can possibly have different
tolerances, which can cause gainers at a splice.
When this occurs, the splice is usually good
and does not require rework.
-continued-
Table 17. Event Types in the Event Table (continued)
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