User's Manual Part 1

6: Installation & Diagnostic Tools
APCD-LM043-8.0 (DRAFT C) 99
Table 15 Radio RSSI Data
The procedure for aligning the EUM antenna is discussed in more detail in Positioning the
Antenna
on page 149.
Data Description
dBm Received radio power measured in dBm.
RX The number of polls received from the CCU. A number between 16
and 700 is normal.
TX The number of payloads transmitted and acknowledged on the first
try from this EUM. This number will always be 0 unless there is
some traffic from the EUM to the network.
R1 The number of payloads transmitted and acknowledged on the
second try from this EUM, implying that the first transmission was
not acknowledged (i.e., failed).
R2 The number of payloads transmitted and acknowledged on the
third try from this EUM, implying that the first two transmissions
were not acknowledged (i.e., both failed).
R3 The number of payloads transmitted and acknowledged on the
fourth try from this EUM, implying that the first three transmissions
were not acknowledged (i.e., all failed).
F The number of payloads not acknowledged after the fourth try from
this EUM. The payload was discarded.
Retry % Total percentage of packet retries over the total number of sent
packets.
SQ SQ is a measure of signal quality. The lower the value, the better.
For EUM and CCU installations, an average value of
8 or less is
good. The “rad rh” command displays a histogram of SQ values,
which indicates the long term quality of the link. It is acceptable to
have occasional values of SQ that are greater than 8, however, if
SQ is consistently above 8, this suggests the radio has trouble
tracking the carrier signal, possibly due to severe multipath or
interference, or low signal-to-noise ratio.
RNA RSSI Noise A (RNA) is an estimate of the signal to noise ratio at
the A antenna in dB. Values above 20 indicate a good signal to
noise ratio, while links with values below 15 are likely to
experience significant packet error rates.
RNB RSSI Noise B (RNB) is the same as RNA above, except it applies
to antenna B.