73
2.048Mb
p
s Wireless Modem
TECHNICAL: 0118 931 2233
The RSSI per channel test displays in graphic format the strength of the received signal on
each of the RF channels used by the 2.048Mbps Wireless Modem. Each vertical column
represents the level of the received RF signal on one of the channels. Available channels are
from 0 to 100 (0 representing 2.400GHZ and 100 representing 2.500GHz), depending on
hopping sequence setting.
Note: In the diagram, 1 represents channel number 10, 2 represents channel 20, and so on;
channels 5, 15 and so forth are marked as +, while the other channels are marked as =.
The height of the column (# signs) represents the relative signal strength. At the top of the graph the
maximum and minimum RSSI levels are given in dBm. An empty column indicates that this is the
channel(s) with the minimal RSSI (channel 47 in the example above). A column with a – sign at the
bottom (channel 39 in the example above) represents a channel that is either blocked or is not
included in the hopping sequence
Note: This graph is used only for measuring an operational link. Note that it measures the
received energy in the band, including possible emissions from other sources. See page82 for
further information on measuring the energy received from undesired sources.
For good fade margin, RSSI levels should allow for at least a 10 dB margin above the
minimal level, determined by the sensitivity at the applicable rate. The following table
provides the RSSI levels required for 10dB fade margin:
Table 3-16. RSSI Levels
Note: The maximum RSSI level must not exceed -10dBm (-25dBm for a Radio Link Rate of 3Mbps)
In the Counters and Tracers menu, type 3 to view the Channel Tracer errors per channel graph.
Figure 3-10. Errors Per Channel Graph