2. Modem Transmission - Swarm-Technologies/Getting-Started GitHub Wiki

Q: Why is my device not transmitting?

Step 1: Is the device placed outside with a clear unobstructed view of the sky?

  • If not, please move the device to an outdoor location that has a clear unobstructed view of the sky. Some options could be an open field, a parking lot, or a rooftop.

Step 2: Is the background RSSI between -95 and -105 dBm?

  • Background RSSI measurements can be enabled by using the $RT command such as $RT 1*17
  • If not, please try a different testing location.
  • If you are still unable to achieve low enough background RSSI measurements, please email [email protected] with clear high-resolution images of your test setup, a serial log of the device during testing, along with all applicable device schematic and layout files.

Step 3: Are there messages queued on the Modem for transmission?

  • The number of outgoing message packets can be checked by using the $MT C=U*12 command.
  • If there are no messages queued for transmission, please queue some messages using the $TD - Transmit Data command. More information regarding this command can be found in the Modem’s Product Manual.

Step 4: Please choose a satellite pass of at least 45° elevation over your testing location using the Swarm Satellite Pass Checker.

  • Ensure that there are messages queued on the Modem for transmission
  • Set the background RSSI polling rate to once every second using $RT 1*17
  • Monitor the serial output for satellite beacon packets represented in the format $RT RSSI=<rssi_sat>,SNR=<snr>,FDEV=<fdev>,TS=<time>,DI=<sat_id>*xx
  • Are the SNR values greater than 0?
  • Were any of the queued transmission packets transmitted and acknowledged as indicated by the $TD SENT unsolicited message using the format $TD SENT RSSI=<rssi_sat>,SNR=<snr>,FDEV=<fdev>,<msg_id>*xx?
  • If no messages were queued, please repeat the test after adding messages to the transmission queue. A few sample messages are: $TD "Test 1"*17 $TD "Test 2"*14 $TD "Test 3"*15

Step 5: If there are no message packets transmitted after following the steps above, please email [email protected] with the following information:

  • All applicable information regarding the device setup including pictures, schematics, PCB layouts, and wiring diagrams.
  • A description of the testing environment including pictures.
  • A serial log file recorded while following the test procedure outlined in Step 4 above.
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