Operator's Manual

OM-E 2072-09689-00
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Figure A-1. Network Occupancy
Use the chart to determine the best sounding cycle for your particular network, bearing in mind
network occupancy, propagation conditions and other considerations.
The following examples demonstrate how to read the chart.
• In a network of nine channels used by eight members, a 30-minute sounding cycle would result
in 80% occupancy; a 60-minute cycle would result in 40% occupancy; a 90-minute cycle would
result in 27% occupancy and a 120-minute cycle would result in 20% occupancy.
• If there are only two or three channels in the network, a sounding cycle of 30 minutes allows
enough channel-free time, even for as many as ten users.
Under field conditions, occupancy will usually be less than the value obtained from the chart because
not every station receives all the soundings that are being broadcast on all channels.
To increase channel-free time for the users by reducing network occupancy, you can try one of these
four methods (in this order):
1. Increase the sounding cycle time (to 90 or 120 minutes).
2. Reduce the number of channels in the network (for example, by using different nets for different
times of day).
3. Reduce the number of stations in the network by re-arranging the hierarchical subgrouping of
stations.
4. Request all stations to set the fast scan rate option.
A-3.2 Manual Sounding
When it is necessary to perform a rapid sounding cycle on all channels instead of, or in addition to the
automatic sounding cycle, manual sounding can be used.