Manual

19
OTDR Testing During the Maintenance Phase
During the maintenance phase, a launch cable is placed between the OTDR and the base station connector (10 –
20 m recommended) allows the loss and reflectance of the base station connector to be measured. Because of a
limited access to the top of a tower/rooftop on the far end, the fiber is plugged into the RRU equipment.
Before performing the OTDR measurement, make sure that the fiber being tested has no signal and that the
equipment is shut down.
Recommendation: overall loss <3 dB; reflectance per connector >–35 dB.
TEST
PP
Launch
Cable C1
Inspect
C1-1
C1-2
Male patch cord
inspection
B
Female bulkhead
inspection
RRU jumper 1-3m
B
PP
B
PP
PP
PP
JB/RRU
BBU
Test the local end (at the BBU at the bottom of the
tower):
. Inspect and, if necessary, clean connectors C and C.
. Inspect and, if necessary, clean OTDR port.
. Connect C to the OTDR port.
. Inspect and, if necessary, clean BBU jumper.
. Connect C to the BBU jumper using a bulkhead adapter.
. Launch OTDR acquisition.
. Check if results pass or fail (use schematic view).
. Save results and generate certification report.
. Inspect and, if necessary, clean BBU port.
. Make the connection.
The OTDR troubleshoots cabling component problems:
y Fiber breaks
y High loss and reflective defects
y Dirty connectors
y Fiber mismatch (two different fiber types spliced or connectorized)
y Misalignment (fiber not perfectly aligned at mating point)
y Macrobends/kinks