CALAMP WIRELESS NETWORKS INC. MCUC5 Manual Do Utilizador

This indicates a possible antenna or feedline
problem which affects SWR (Standing
Wave Ratio).

 

Approximate measure of reverse (reflected)
power. The value is returned differently for on-
line and offline diagnostics:

 

Online: The value returned is 0 if reverse power

is within acceptable limits, 1 if reverse
power is too high. The threshold is set to
approximately 1/4 of the forward power
value.

 

Offline: Value is in watts to the nearest tenth.

This value is intended as an indication of
antenna problems and will normally be used
for trend monitoring. Ideally it should close
to be zero, but values up to about 15% of
Forward Power may be encountered  in
properly operating systems.

A reverse power reading above zero is an indi-
cation that the antenna, feedline or connectors
are damaged, corroded or improperly tuned.
This creates standing waves which are reported
as a Standing Wave Ratio (SWR).

The following table, which is based on a for-
ward power of 5 watts (it may be scaled for
lower power settings) gives guidelines to inter-
preting these figures:

1:1

0

ideal situation

1.5:1

0.2

normal operation

2:1

0.6

should be investi-
gated

3:1 or

greater

1.25 or
greater

defective antenna,
feedline or connec-
tors.

In the case that the values returned by the built-
in diagnostics seem to indicate a problem, we
recommend verification by means of proper ra-
dio shop equipment.

This is the number of good received data trans-
missions out of the last 15.

The receive quality indicator value returned by
any remote unit to the master station is an indi-
cation of the reception quality on the outbound
path.

If the master station is monitored, either from a
remote station or by using a local GET STATS,
users should note that the receive quality indi-
cator thus returned is a composite value which
represents the average reception from the last 15
remotes. Any significant drop in the receive
quality indicator returned by the master station
is therefore likely to indicate a problem with the
master station receiver itself, rather than any one
remote station.

Offline diagnostics are returned in response to a
specific request to a particular station. Requests
are issued using the Integra-T RDS, either lo-
cally or remotely from another station. This may
cause slight temporary network disruption.

The diagnostic information available is similar
to that available from online diagnostics with
the following additions:
Demodulated signal voltage: peak-to-peak
Analog 1 input voltage: 0 – 10 V in tenths
Analog 2 input voltage: 0 – 10 V in tenths
Reverse power: tenth of watts rather than a good
or poor value.

Note: Analog 1 and 2 have 8 bits of resolution.