Fluke OF-500-01 OptiFiber, Technical Reference Handbook, Page: 80 / 278

OF-500 OptiFiber Certifying OTDR
Technical Reference Handbook
3-4
Note
Avoid using hybrid patch cords to connect to the
cabling under test. Connect the launch and receive
fibers directly to the cabling under test, using a
launch fiber with the appropriate connectors. This
provides the best measurement of the connectors
at the ends of the cabling. Hybrid launch fibers
with various connector styles are available from
Fluke Networks.
Compensating for Launch and Receive Fibers
The launch fiber compensation function marks the end of
the launch fiber and the beginning of the receive fiber, if
used, on OTDR traces and labels these events in the event
table. It also removes these fibers’ losses, lengths, and
attenuation coefficients from overall OTDR results. The
losses of the connections at the launch and receive fibers
are not removed from the results.
Launch compensation also provides a more accurate ORL
(optical return loss) measurement, provided that the correct
backscatter coefficient for the fiber under test is entered on
the Cable tab in SETUP.
The compensation function does not affect ChannelMap
and real time trace results.
Types of Compensation
The tester offers three types of compensation:
•
Launch Only: Lets you compensate for a launch fiber.
•
Receive: Lets you compensate for a launch
fiber and a receive fiber.
•
Fiber + Receive: Lets you compensate for a
launch and receive fiber if you have forgotten to do so
before the receive fiber was taken to the other end of
the cabling.
Notes
Receive compensation usually provides
the most accurate measurements.
Avoid using Fiber + Receive
compensation on fibers longer than 8 km. Doing
so may degrade measurement accuracy.
Setting the Launch Fiber Compensation
1 Select the fiber type to be tested on the Cable tab in
Setup.
2 Press
F
; then select Set Launch Fiber
Compensation.
3 On the SET LAUNCH METHOD screen highlight the
type of compensation you want to do, but do not press
t
.