User guide

DATA-LINC GROUP
29
PLR580D / DA User Guide
PN 161-09889-001B
rev 3/2005 ver 6.33c
Main Menu Option (4): Show Radio Statistics
Option (4) in the main menu allows the user to view data transmission statistics, which have been gathered by the
Transceiver during the most recent session. Statistics are gathered during each data link and are reset when the next
link begins. Ideally, noise levels should be below 30, and the difference between the average signal level and average
noise level should be 15 or more. High noise levels tend to indicate other sources of RF interference, while low signal
levels indicate a weak link. The “Local” stats are the statistics that are being gathered by the modem you are connected
to while “Remote1, Remote2, and Remote3” are the stats of the repeater(s) that the modem you are attached to is using
to get back to the master modem. The following sections provide information useful to the process of troubleshooting
and improving radio links.
Average Noise Level
The average noise level indicates the level of background noise and interference at this modem and at each of
the modems used as repeaters in the link. The number is an average of the noise levels measured at each
frequency in the modems’ frequency hop table. The individual measurement values at each frequency hop
channel are shown in the frequency table. The frequency table is accessed by pressing the ENTER key on the
computer when the radio statistics menu is displayed. Average noise levels will typically fall in the range of 15 to
30. Average 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 improved with bandpass filters, antenna
placement or antenna polarization. Please contact Data-Linc Group for more information.
Average Signal Level
The average signal level indicates the level of received signal at this modem and at each of the modems used as
repeaters in the link. For each of these, the signal source is the modem that transmits to it. The number is an
average of the received signal levels measured at each frequency in the modem’s frequency hop table. The
individual measurement values at each frequency hop channel are shown in the frequency table. The frequency
table is accessed by pressing the ENTER key on the computer when the radio statistics menu is displayed.
For a reliable link, the average signal level should be at least 30 higher than the average noise level reading. The
table below provides an approximate conversion of average signal level values into the more common dBm
(decibel milliwatts). Low Average Signal Levels can often be corrected with higher gain antennas, antenna
placement, and use of repeaters. Contact Data-Linc Group for more information.