Symbol WS5000 Series System Reference Manual page 691

Figure 14.13 Without the antenna, many packets had 1 to 4 retries.
The "raw" stats also accumulate the number of packets received, the sum of all signal values on those packets,
and the sum of all each signal value squared. Taking the delta of each of those values over both the interval
with the antenna present and absent, results in average signal readings with corresponding standard
deviations.
With the antenna absent, the average signal was –88.5 dB with a stddev of 3.4, (meaning that 67% of packets
had signal values of –91.9 to –85.1 dB).
Note The greater variance while the antenna is present can be explained by the
fact that the AP radio has a certain floor of receive sensitivity, probably around –
91 dB. This fact compresses the range of possible values.
With the antenna present, the average signal was –63.6 with a stddev of 10.2 dB. Assuming the signal
readings fit a normal distribution, those curves would look approximately as shown in
these values match very close to the values, (–89 and –67 dB), shown in
Enhanced RF Statistics
Figure 14.14. Note that
Figure 14.10.
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