Cisco Cisco WT2750 Multipoint Broadband Wireless System Guia De Informação
Wireless Point−to−Point Troubleshooting FAQ and
Checklist
Checklist
Document ID: 14241
Contents
Introduction
What must I do or look for when my link does not work?
How can I check to determine if there is interference?
What must I do when I confirm that I have an interference problem?
Can you give a short troubleshooting checklist for a point−to−point link?
Related Information
How can I check to determine if there is interference?
What must I do when I confirm that I have an interference problem?
Can you give a short troubleshooting checklist for a point−to−point link?
Related Information
Introduction
This document provides questions and answers for wireless point−to−point troubleshooting.
Refer to Cisco Technical Tips Conventions for more information on document conventions.
Q. What must I do or look for when my link does not work?
Symmetrical Signal LossConfirm that the receive signal level at each receiver end
is close to the expected value. The value must not be lower than 4 dB below the
original value. If the value is lower, especially if the value is lower by the same
amount at both ends, you can suspect a problem with the antennas or cabling or
connectors. Symmetrical signal loss can occur doe to misaligned antennas.
is close to the expected value. The value must not be lower than 4 dB below the
original value. If the value is lower, especially if the value is lower by the same
amount at both ends, you can suspect a problem with the antennas or cabling or
connectors. Symmetrical signal loss can occur doe to misaligned antennas.
♦
MoistureMoisture can also damage antennas or connections. If not properly sealed
at installation, moisture can condense inside antenna feedhorns and fill them within a
few weeks! Moisture that gets into coax cabling is even more insidious and the
damage that moisture causes is both invisible and severe. Most coax cable types have
a foam−type internal dielectric, which can act like a sponge, soaking water into the
coax for a significant portion of its length.
at installation, moisture can condense inside antenna feedhorns and fill them within a
few weeks! Moisture that gets into coax cabling is even more insidious and the
damage that moisture causes is both invisible and severe. Most coax cable types have
a foam−type internal dielectric, which can act like a sponge, soaking water into the
coax for a significant portion of its length.
Note: Do not merely cut off a few inches from the affected end and re−install the
connector! If you find that moisture has ingressed into your coax cable, replace the
entire run length.
connector! If you find that moisture has ingressed into your coax cable, replace the
entire run length.
♦
Outdoor System FaultsFaults that develop within the outdoor parts of a system, for
example the antennas and cables, manifest in a receive−signal level that is degraded
by the same amount at both ends of a link. That is, the entire outdoor system acts
bilaterally. Therefore, if you note a degraded receive−signal power measurement at
the first end that you measure, do not assume that the fault is with components at that
end; the fault can also be at the other end.
example the antennas and cables, manifest in a receive−signal level that is degraded
by the same amount at both ends of a link. That is, the entire outdoor system acts
bilaterally. Therefore, if you note a degraded receive−signal power measurement at
the first end that you measure, do not assume that the fault is with components at that
end; the fault can also be at the other end.
♦
Asymmetrical Signal LossFinally, if the receive−signal level is low at one end but
not the other, you can conclude that the outdoor system inherently functions properly.
Such asymmetrical situations are commonly either the result of improper setup or
configuration of the radio units (for example, TX power is set too low at one end), or
of interference. Therefore, do not re−align antennas or take RF connections apart. If
the setup is deemed to be correct and equipment failure is ruled out, interference is
the likely issue.
not the other, you can conclude that the outdoor system inherently functions properly.
Such asymmetrical situations are commonly either the result of improper setup or
configuration of the radio units (for example, TX power is set too low at one end), or
of interference. Therefore, do not re−align antennas or take RF connections apart. If
the setup is deemed to be correct and equipment failure is ruled out, interference is
the likely issue.
♦