Motorola PTP 500 - Manual (Page 16)

Before installing the units, Please ensure that any new obstacle has been entered in the
LINKPlanner and that a new report has been printed.
The Motorola PTP 300 and PTP 500 Series use audible tones to assist the installer with ODU
alignment. The pitch (frequency) of the tone is relative to the received signal strength. The
higher the received signal strength the higher the frequency of the tone emitted.
Once the link is in the ‘Registered’ state optimum alignment is achieved by aligning for maxi-
mum frequency of the tone. If the link is affected by slow fading the frequency of the tone will
vary. Under these conditions it is necessary to spend several minutes slowly adjusting the
alignment to ensure the maximum average frequency is achieved.
The meanings of the audible tones are shown in the table below:
Table 3 - Audio indications from the ODU
The term ‘wanted signal’ in the table above refers to that of the paired unit being installed. In
each of the states detailed in the table, the unit should be aligned to give the highest pitch
tone. It should be noted that if, when in the Synchronised or Registered states, the tone var-
ies wildly, you may be suffering from interference or a fast fading link. Installing in this situa-
tion may not give a reliable link. The cause of the problem should be investigated before fi-
nalizing the installation.
Due to the behavioural differences of Master and Slave units it is highly recommended that
the Master unit is installed first and the initial alignment carried out at the Slave unit. Use the
LINKPlanner report which provides installations notes such as bearing, tilt, power settings,
antenna heights, etc.
Once the optimum performance has been achieved by directing the Slave unit (indicated by
highest frequency of tone or voltage output on the BNC connector of the ODU, which gives
an indication of RX signal strength) then adjustment of the direction of the Master unit should
be done without moving the Slave. Repeat as necessary at the Slave and then the Master
until optimum alignment has been obtained.
It is also possible to use the ‘Graphical Install’ from the main HTTP management interface.
State Name Tone Description State Description
Free Channel
Search Regular beep Executing band scan.
Scanning Slow broken tone Not demodulating wanted signal.
Synchronized Fast broken tone Demodulating the wanted signal.
Note: During acquisition there may be cycling be-
tween Scanning and Synchronized states until the
alignment is sufficient to maintain the link up.
If the fast broken tone disappears after 3 seconds,
the unit may be pointing at the wrong PTP 500. Alter-
natively it may be detecting the correct PTP 300/500
but the signal is too weak to establish a link.
Registered Solid tone Both Master and Slave units exchanging Radio MAC
layer management messages.
Installation and Commissioning
16