Motorola PTP 500 User Manual download pdf (Page 21)

Installation and Commissioning

Behaviour During Installation

The following behavior should be noted:

• Band scan: 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 the Scanning state with the pitch of the tone set to

the background noise level. Alignment of the unit should cease during this time.

• Radar detection: If the unit is operating where mandatory radar avoidance algorithms are

implemented, the ranging behaviour for the 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 a 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.

• Ranging: The PTP 300 and PTP 500 Series do not require the user to enter the link range.

The Master unit typically takes less than 60 seconds to determine the length of the link being

installed. 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.

• Retrying same channel: 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.

• Slave unit: 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.

DVM Alignment

It is possible to use the BNC connector on the PTP 500 Series ODU and a digital voltmeter (DVM) to help

with the alignment process. The BNC connector provides an analogue voltage which is proportional to the

received signal strength. To use, remove the protective cap from the case mounted BNC connector and

connect a DVM. You may have to invert the pole for correct reading. The user guide shows the relationship

between measured values and the receive signal strength.

More information:

PTP 300 Series User Guide

or PTP 500 Series User Guide

Section: “Establishing a Radio Link”

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Motorola PTP 500 User Manual Page 21