What should be monitored?
The elements of the network that should be monitored are:
- RF Equipment
Many new base stations come with advanced monitoring functions built in, and third party devices are capable of monitoring transmitter power and antenna system malfunctions. The extent to which the RF equipment should be monitored depends on the needs of each system owner, but monitoring output of all transmitters is the recommended minimum.
Repeater functions and parameters that should be monitored include:
- Tx output power (out of repeater and into the antenna system),
- Tx modulation level,
- VSWR (Voltage Standing Wave Ratio),
- Tower Top Amplifier operation (where applicable),
- Rx channel interference.
You should monitor base stations’ receive frequencies for interference, and take them out of service remotely if necessary – either automatically or manually.
If you are using your own microwave or fiber network, these technologies have network monitoring built in and can trigger alarms/switchovers when transmission parameters are compromised. If your backhaul is provided by a third party, include monitoring as part of your service agreement, with clearly identified performance parameters.
Paradoxically, even though backhaul service providers often use sophisticated technologies, they do not operate in a mission-critical environment, and backhaul failures commonly affect Public Safety radio systems, especially dispatch.
Site monitoring can employ techniques from motion detectors, contact closures on doors, to live video monitoring at high risk sites. Sites should be monitored for:
- high or low temperature inside the shelter,
- humidity/moisture ingress,
- power disruption,
- generator fuel/battery bank voltage levels,
- tower light malfunctions (where applicable),
- grounding system malfunction,
- back-up generator malfunction.
Systems and devices that remotely monitor the technical parameters of subscriber units can detect some problems early, especially those related to transmitter performance and antennas, saving you time, money and grief.
Traffic reports from network management tools can provide information about the activities of individuals and groups, that can identify misuse, capacity problems or technical issues that subscribers may be unaware of.
The biggest challenge for dispatch centers is backhaul network failure. The actual dispatch positions do not need much technical monitoring, assuming they are manned 24/7 and that dispatchers recognize and report issues quickly.
Some industry practitioners recommend monitoring and analyzing dispatch position usage stats, such as number of PTTs in a given period of time. This can be useful in managing workload efficiently.
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