Motorola PTP 400 Series - Manual (Page 64)

62
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 time the installation tone on the master unit will drop back to the band scan state and the
Slave unit will drop back to Scanning state with the pitch of the tone set be the background
noise level. Alignment of the unit should cease during this time.
The master unit can take between 30 seconds in 0-5km (0-3 miles) mode to 300 seconds in
0-200km (0-124 miles) mode to determine the range of the link being installed 14 . The Master
unit will remain in the Scanning state until the range of the link has been established. The
Master unit will only move to the Synchronized state when the range of the link has been
established.
If at the end of the ranging period the ‘Registered’ state is not achieved due to interference or
other reasons, the Master unit will retry twice more on the same channel before moving to
another available channel. Should this occur it might take a number of minutes to establish a
link in the ‘Registered’ state.
The Slave unit does not have a ranging process. The slave unit will change to the
Synchronized state as soon as the wanted signal is demodulated.
When the alignment process is complete the installer MUST REMEMBER TO DISARM BOTH
UNITS in the link as described in section 8.3.5. This is necessary for the following:
• Turn off audible alignment aid.
• Enable Adaptive Modulation
• Fully enable Dynamic Frequency Selection
• Clear unwanted installation information from the various systems statistics
• Store the link range for fast link acquisition on link drop
• Enable Higher Data Rates
14 If the unit is operating where mandatory radar avoidance algorithms are implemented the ranging
behavior for the 400 Series Bridge may be affected. The Master has to monitor the initially chosen
channel for 60 seconds to make sure it is clear of radar signals before transmitting. If radar is
detected during any of the installation phases a further compulsory 60 seconds channel scan will take
place as the master unit attempts to locate a new channel that is free of radar interference.