Fluke DTX-1800, Техническое справочное руководство

Страница: 219 / 398

Certifying Fiber Optic Cabling
Essentials for Reliable Fiber Test Results
8-11
8
W
Caution
Do not disconnect the test reference cords from
the testers' output ports after setting the
reference. Doing so may alter the amount of
optical power launched into the fiber and
invalidate the reference.
Reference values should not change by more than a few
tenths of a dBm from day to day. Larger changes may
indicate a problem with the test reference cords or
connections.
See the sections on Smart Remote, Loopback, and Far End
Source modes for details on setting the reference for each
mode.
After you set the reference, you can enter the lengths of
the test reference cords used for reference and test
connections. The lengths are included with saved results to
meet TIA reporting requirements for fiber test results.
Selecting Test Reference Cords
The DTX Fiber Modules come with high-quality test
reference cords.
To ensure that your measurements are accurate and
repeatable, use test reference cords provided by Fluke
Networks or cords of the same quality. See "Replacing Fiber
Test Reference Cords" on page 14-8.
W
Caution
When testing links with APC (angled physical
contact) connectors, use only test reference cords
with APC connectors on the ends connected to the
link, and UPC connectors on the ends connected
to the testers. Connecting non-APC connectors to
the link will produce large reflections that affect
loss measurements.
Testing Your Test Reference Cords
You must test your test reference cords at regular intervals.
Use the procedure given in Appendix A to test the cords
initially. After that, use the procedure given with the
procedures for certifying cabling to monitor the condition
of the cords.