Spread Spectrum Wireless Data Transceiver User Manual
A
NTENNA
R
EFLECTED
P
OWER
This is a measurement of the transmitted power that is reflected back into the transceiver from
mismatched antennas or cables, or loose connections between the transceiver and antenna. A reading
of 0-5 is good; 5-30 is acceptable; 30+ indicates that the connections should be inspected for loose
connections and cable quality.
T
RANSMIT
C
URRENT
(
M
A)
This measures the current draw of the radio in milliamps. Refer to Transceiver specs for typical values.
A
VERAGE
N
OISE
L
EVEL
The average noise level indicates the level of background noise and interference at this transceiver and
at each of the Repeaters in the link. The number is an average of the noise levels measured at each
frequency in the transceiver’s frequency hop table. The individual measurement values at each frequency
hop channel are shown in the frequency table. Pressing the
Enter
key on the keyboard when the Radio
Statistics menu is displayed accesses the frequency table.
Ideally, noise levels should be below 70 J units and the difference between the average signal level and
average noise level should be 26 or more. Noise levels significantly higher than this are an indication of a
high level of interference that may degrade the performance of the link. High noise levels can often be
mitigated with band pass filters, antenna placement or antenna polarization.
A
VERAGE
S
IGNAL
L
EVEL
The average signal level indicates the level of received signal at this transceiver and at each of the
Repeaters in the link. For each of these, the signal source is the transceiver that transmits to it. The
number is an average of the received signal levels measured at each frequency in the transceiver's
frequency hop table. The individual measurement values at each frequency hop channel are shown in the
frequency table. Press the
Enter
key on the keyboard when the Radio Statistics menu is displayed
accesses the frequency table. For a reliable link, the margin should be at least 26 J units. Low Average
Signal Levels can often be corrected with higher gain antennas, better antenna placement, additional
Repeaters and/or antenna amplifiers.
Note:
Later revisions of the firmware show the signal level in RSSI units.
O
VERALL
R
CV
R
ATE
(%)
The Overall Receive Rate measures the percentage of data packets that were successfully transmitted
from the Master to the Slave on the first attempt. A number of 75 or higher indicates a robust link that will
provide very good performance even at high data transmission rates. A number of 15 or lower indicates a
weak or marginal link that will provide lower data throughput. An Overall Receive Rate of 100% will
provide approximately 100 Kbaud of bandwidth with an RF Data Rate setting of 3 and approximately 150
Kbaud of bandwidth with an RF Data Rate of 2. These numbers are reduced approximately 50% if there
are one or more Repeaters in the network.
R
ADIO
T
EMPERATURE
The radio temperature value is the current operating temperature of the radio in degrees Celsius. For
proper operation, FreeWave radio transceiver must be in the temperature range of -40° to +75° C.
MultiPoint Parameters
When installing MultiPoint systems it is important that some planning is done up front. Unlike Point-to-
Point networks, a Point-to-MultiPoint network requires that several parameters are set consistently on all
transceivers in the network. This includes RF data rate, min and max packet size, number of Repeaters,
and frequency key.
Furthermore, if several independent MultiPoint systems are to be located in close proximity the
planning becomes more critical. In this scenario it becomes very important to include as much
LUM0002AD Version
6.1
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