I did the math on my the -107dBm of signal my meshtastic device (heltec meshpocket: fun toy, recommend) was successfully receiving messages with, and that's 20 x 10^{-15} watts. That's not 20 milli-, not 20 micro-, not 20 nano-, not even 20 pico-, but 20 FEMTOwatts, y'all. That's absurd. One Joule in 50 trillion years. I hope I'm not overselling because I did the math wrong.
making direct connections on a good day with someone 2-3 miles away, and like 6-7 hops away from youngstown, OH?? wild

@jcreed don't expect it to be spectacularly secure: IIRC a friend had a bit of a poke and found it wasn't too hot there

but then, if the grid's down, better any communication capability than none

@flippac yeah, I used the word "toy" on purpose to remind myself the level at which I should rely on it in any particular engineering quality criterion. But it is neat!