Here are some things I have found that help with reliability
- Give the thing plenty of power and multiple power options
There is a surge in power demand when trasmitting to a satellite that easily causes the modem to reset
Modem has to transmit before it receives so you will never receive anything if it can’t check in with the satellite
I have 4 18650s in parallel running to the pins on the breakout board plus a USB C PD power bank
Messages going down from the satellite to the modem
Go to ONE satellite that is expected to pass over you at some point
This means you might be waiting a while
It’s just finicky when it comes to getting the M138 and the satellite to talk
This is a tiny satellite network. TINY. It is not startlink or iridium. We are here because the service is cheap.
I added an HC-05 bluetooth serial adapter to the M138 and have the whole thing in a box on the roof of my car. This has helped a LOT in getting messages sent and received as I happen to move the car daily. YMMV.
There are particulars when dealing with the connectors and ground planes
TBD
Note the eval unit at Swarm that has a tripod and an angled solar panel as a ground plane. I would assume a smart engineer made those choices for a reason.
Help with serial, wiring, power, etc I’m not covering (yet?). I would like to update this post with more info as available.
Make sure to use the Spark Fun M138 Modem GUI and be nice to Paul!
