Parameter
Description
rssi_bkgnd
Received background noise signal strength in dBm for open channel
(integer).
For reliable operation, this value should consistently be less than
(more negative) than
-93
dBm:
rssi_bkgnd
>= -90 dBm
Bad (not likely to work)
rssi_bkgnd
<= -93 dBm
Marginal
rssi_bkgnd
= -97 dBm
OK
rssi_bkgnd
<= -100 dBm
Good
rssi_bkgnd
<= -105 dBm
Great
rssi_sat
Received signal strength in dBm for packet from satellite (integer)
snr
Signal to noise ratio in dB for packet (integer)
fdev
Frequency deviation in Hz for packet (integer)
time
Date and time (UTC) of received packet
sat_id
Device ID of satellite heard (hexadecimal)
Notes:
See the section
for a description of
<error_type>
.
<rate>
is a value between 1 and 2147483647 (2
31
-1). It will be the number of seconds in
between each message. If
<rate>
is 0, no messages will be sent, and no packets received
from a satellite will be displayed.
For reliable performance, the noise floor can be measured with an antenna connected to the
device in the final built-up configuration. The
rssi_bkgnd
value reported by
$RT
should be less
than (a more negative number) than
-93
dBm. If the
rssi_bkgnd
noise floor is more than (a less
negative number, e.g. -88 dBm)
-93
dBm, then the customer should relocate the device to a
different location, reconfigure the device ground plane, and also check that their DC-DC power
supplies on their own PCB are not injecting RF background noise into the device.
© 2022 SWARM TECHNOLOGIES
SWARM M138 MODEM PRODUCT MANUAL · REV 1.20 · FEBRUARY 2022
PAGE
68