Verifying Isolation - Cisco Aironet 1400 Series Hardware Installation Manual

Chapter 4 Stacking Bridges
At each site location, temporarily install the second link 2 bridge, positioning the antenna toward the
Step 4
intended location of the corresponding link 2 remote antenna.
Note

Verifying Isolation

Isolation measurements are valid only if the link 1 bridges are operating at maximum power. By default,
the bridge operates at maximum power.
To verify signal isolation, refer to
Ensure that the link 1 bridges are operating at full power and bridge A is configured as the root bridge.
Step 1
At Site 1, measure the isolation between bridges A and B:
Step 2
a.
b.
c.
Go to the remote Site 2 location to measure the isolation between bridges A and D:
Step 3
a.
b.
c.
d.
Step 4 At Site 2, measure the isolation between bridge C and D by following these steps:
a.
b.
c.
OL-4072-04
You can improve system isolation by using different polarizations for the two local antennas. For
example, if the link 1 system has vertical polarization, assemble the link 2 system for horizontal
polarization.
Activate the link 2 bridge (bridge B) as a non-root bridge and let it associate to bridge A (the root
bridge).
Connect a voltmeter to the RSSI port of bridge B, and verify that the voltage is 1.95 V (–40 dBm)
or less. If the voltage exceeds 1.95 V, move the bridge farther away and repeat this procedure.
Slowly rotate the bridge B antenna a few degrees to the left and to the right and verify that the RSSI
level does not rapidly spike above 1.95 V. If the voltage peaks above 1.95 V, move the bridge farther
away and repeat this step.
Activate the link 2 bridge (bridge D) as a non-root bridge and let bridge D associate to bridge A (the
root bridge).
Connect a voltmeter to the RSSI port of bridge D and align the bridge D antenna with bridge A so that
the RSSI voltage is maximized.
When the antennas are fully aligned, if the RSSI voltage level is greater than 1.95 V, the bridge sites
are very close. Reduce the output power on all bridges at both sites (bridges A, B, C, and D) to 12
dBm.
If you are still unable to reduce the RSSI voltage level to 1.95 V, change the polarization of the link
2 bridges (bridges B and D). For example; change the antenna polarization from vertical to
horizontal.
Turn off bridge A for this measurement.
Activate the link 2 bridge (bridge D) as a non-root bridge and the link1 bridge (bridge C) as a root
bridge and let bridge D associate to bridge C.
Connect a voltmeter to the RSSI port of bridge D and verify that the voltage is 1.95 V (–40 dBm) or
less. If the voltage exceeds 1.95 V, move the bridge farther away and repeat this step.
Cisco Aironet 1400 Series Wireless Bridge Hardware Installation Guide. OL-4072-03
Figure 4-1 as you follow these steps:
Verifying Isolation
4-3