Manual

17
OTDR Testing During the Construction Phase
Testing Tx and Rx Fibers Using a Loopback (recommended)
During construction, a patchcord loop (20 m) is placed on each duplex pair after tower/rooftop installation: a
patch cord is looped at the top for a test of the duplex pair. A patch cord allows the two duplex pairs to be
measured for loss and reflectance. A launch cable placed between the OTDR and the base station connector and
a receive cable placed on the far side of the down-loop base station connector (10– 20 m recommended for each)
allows the loss of each of the base station connectors to be measured. On the far end of the receive cable, a
non-reflective terminator or an APC connector is recommended to minimize the reflectance on the far connector.
Recommendations: overall loss should be <6 dB; reflectance per connector should be >–35 dB.
TEST
PP
PP
PP
PP
Launch
cable C1
Inspect
C1-1
C1-2
C2-1
L1-1
L1-2
Male patch cord
inspection
Female bulkhead
inspection
Bulkhead
Loopback
B
PP
PP
PP
PP
PP
B
PP
PP
PP
Receive Cable C2 with
non-reective termination
JB/RRU
BBU
Non-reflective termination
Test the remote end (at junction box JB/RRU at the top
of a tower):
. Inspect and, if necessary, clean connectors L and L of the
loopback device.
. Connect the loopback device on the fiber pair under test using
a bulkhead adapter.
. Wait for the end of OTDR acquisition from the BBU.
. After the OTDR test is complete, disconnect loopback, inspect, and,
if necessary, clean the RRU port.
. Make the connection.
Test the local end (at the BBU at the bottom of a tower):
. Inspect and, if necessary, clean connectors C and C
. Inspect and, if necessary, clean the first BBU jumper connector.
. Inspect and, if necessary, clean the OTDR port
. Connect C to the OTDR port.
. Inspect and, if necessary, clean connectors C and C
. Inspect and, if necessary, clean the second BBU jumper connector
. Connect c to the second BBU jumper using a bulkhead adapter.
. Launch OTDR acquisition
. Check if results pass or fail (use schematic view)
. Save results and generate a certification report.
. Inspect and, if necessary, clean BBU ports.
. Make the connection.