Cambium Networks PTP 820 Series, User Manual, Page: 1070 / 1149

Chapter 25: Fault Finding Troubleshooting Tips
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Page 25-3
Troubleshooting Tips
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For dual-polarization and XPIC links, if one of the polarizations has significantly reduced performance, check to
make sure the antenna’s rectangular interface was replaced with a circular adaptor.
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For dual-polarization and XPIC links, the RSL should be similar for both polarizations. For XPIC links, the XPI
value should be similar for both polarizations; the difference should not be more than 2 dB.
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In case of a Radio loss of frame alarm on an PTP 820F unit, the problem is most likely with the RFU or the RFU-
antenna connection rather than the IDU.
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For PTP 820F, a Radio unit communication failure alarm generally means a problem with the radio cable, faulty
cable grounding, or faulty cable quality. If in addition to this alarm a Cable open is raised and the RFU is
receiving power via an external power source rather than PoE from the IDU, check the Radio Unit
configuration to make sure
Power Admin is set to Disable . See Configuring the IDU-RFU Connection (PTP 820F
only). Check also for a Cable short alarm, which would indicate a problem with the IDU-RFU cable.
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For PTP 820F, a Radio unit communication failure alarm is often the result of a physical cable failure. If the
interface LED on the RFU (RJ-45 or SFP) displays Orange, it means this alarm is raised without Loss of Carrier.
This probably means the cable is not connected well. Otherwise, problem is probably with the IDU.
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For PTP 820F, there is an automatic software upgrade process to ensure that the RFU is always aligned to the
IDU. Sometimes, usually due to excessive switching of the physical RFU unit by the user, this process fails.
When this happens, the IDU makes five recovery attempts. If the failure persists, a
Radio unit not aligned to
IDU alarm is raised. To resolve this alarm: (i) Disable, then enable the RFU in the Radio Unit page ( Configuring
the IDU-RFU Connection (PTP 820F only)), and (ii) Reset the IDU chassis.
If this alarm occurs
other than as part of a hardware installation or after a software upgrade, there is probably
a problem with the RFU, and the RFU should be replaced. After replacing the RFU, Disable, then enable the
RFU in the Radio Unit page (
Configuring the IDU-RFU Connection (PTP 820F only).
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For RFU-D, RFU-D-HP, RFU-E, and RFU-S: If there is a problem with the RFU while using an RJ-45 connection,
try using an SFP connection. If the problem is eliminated, the problem was probably with the cable or cable
grounding.
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If during or right after a software upgrade the message Your session has expired, please login again appears
and you cannot log in, it is recommended to refresh the Web EMS page (F5) after completion of the upgrade.
If pressing F5 does not help, clear the browser’s cache by pressing Ctrl+Shift+Delete.