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Before physical installation takes place the units to be installed should be set up as described
in the Section 8.3.6. This process will give the installer the opportunity to set the units IP
address to one that is in the desired address range and set each unit up with the MAC address
of its peer unit ready to establish a radio link. It is recommended that this procedure be carried
out on the bench before physical installation commences. Providing it is safe to do so the
installer should take the process to the point where a radio link is established before
proceeding to the installation site.
7.7.10 Aligning the ODUs
The following is a description of the steps taken to establish a radio link between the two units
forming the bridge and align the units for the best signal strength.
The 30/ 60 Mbps Backhaul uses audible tones during installation to assist the installer with
alignment. The installer should adjust the alignment of the ODU in both azimuth and elevation
until highest pitch tone is achieved
State Name
Tone Description
Band Scan
Regular beep
Scanning
Slow broken tone
Synchronized
Fast broken tone
Registered
Solid tone
The term 'wanted signal' refers to that of the peer unit being installed.
In each of the states detailed above the unit should be aligned to give the highest pitch tone. It
should be noted that if, when in the Synchronized or Registered state the tone varies wildly,
you may be suffering from interference or a fast fading link. Installing in this situation may not
give a reliable link. The cause of the problem should be investigated.
For the ease of alignment both Master and Slave units use the install tones in the same way
but with some small behavioral differences. This allows the installer to install the Slave unit first
and carry out the initial alignment with the Master unit if desired. However due to the Behavioral
differences of Master and Slave units it is recommended that the Master unit is installed first
and the initial alignment carried out at the Slave unit.
The following behavior should be noted:
When first started up and from time to time the Master unit will carry out a band scan to
determine which channels are not in use. During this time, between 10 and 15 seconds, the
Master unit will not transmit and as a consequence of this neither will the Slave unit. During this
3
The pitch of the alignment tone is proportional to the power of the 5.8 GHz wireless signals.
The best results are usually achieved by making small incremental movement in angular
alignment.
Issue 3.1, July 2006
3
. The tones and their meanings are as follows:
State Description
Executing band scan
Not demodulating the wanted
signal
Demodulating the wanted signal
Both Master and Slave units
exchanging Radio layer MAC
management messages
Table 5: Audio indications from the ODU
Pitch Indication
(Higher pitch =
higher power)
N/A
Rx Power
Rx Power
Rx Power
Page 46 of 162
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