My First Impressions of MeshCore Off-Grid Messaging

51 points by mtlynch

benjajaja

The good news is that all that hardware can be used with Meshtastic, which is open source.

thombles

I'm not here to argue anything in particular, but if you're enthusiastic about open source you may want to know that LoRa (the radio technology underpinning meshtastic) is proprietary and you have to buy a licensed chip to create compatible hardware. There are other radio modulation techniques of course but they're not as polished and... well, you know the drill.
- Bernerd
  
  Modulation-wise there are only three ways to go: fast, long, and random :D Fast: Put as much info into one symbol as is still discernible. OFDM Wifi, n-QAM for big n Long: Stretch the "same" symbol over longer time then integration increases the signal to noise distance. Here the linear chirp spread spectrum like in LoRa is nearly optimal in signal processing sense. Random: Each symbol is a pseudo-random sequence of signal states. This ultrawideband tech was dropped for data transmission purposes. Used in location tracking, synthetic aperture and encrypted radar
hoistbypetard

My wife has many wonderful qualities, but, if I’m being honest, “enthusiasm for encrypted off-grid messaging” has never been one of them.

Same. But "tolerating my enthusiasm for encrypted off-grid messaging as long as it doesn't become a cripplingly expensive or time consuming hobby" is. Also, her tolerance for that is inversely related to the number of words she needs to hear about it.

Thanks for sharing this. I was interested in a T-Deck, and now I'm a lot less interested.
- wrs
  
  This is funny because it's my wife who is the prepper in our household. I never know when a new giant battery pack or insulated car camping tent or twig fire USB charger (yes, that is a thing) will arrive. Maybe I should ~~fight back~~ go along by getting into off-grid messaging.
  - Vaelatern
    
    twig fire USB charger
    
    This is ungoogleable since Amazon makes a Fire Stick that needs a charger. What is this?
    
    wrs
    
    BioLite CampStove 2+
    
    It's a camping stove that burns twigs, with a thermoelectric generator and a USB jack.
    
    Vaelatern
    
    That's nifty, thanks for sharing!
    
    eduard
    
    I’m not exactly a doomsday prepper, but I plan for realistic disaster scenarios like extended power outages, food shortages, and droughts.
    
    This is definitely a valid concern, this year's power outage in Spain and Portugal is a good example of an event in which having alternative communication methods pays off.
    
    lenny
    
    Having been there during the outage in person on a vacation, the mobile communications networks were surprisingly resilient! Traffic lights were off, no power outlet worked, but 4/5g worked fine.
    
    koala
    
    In some places. At least in the zone of Madrid where I was at the moment, 4/5G was mostly dead. The outage was quite uneven. (My family was in a zone of Barcelona where power was restored in 4-5 hours, whereas it was over 10 hours for me, and even longer in other places.)
    
    mtset
    
    Be aware that the default settings in the US are probably against the law; at only 61.5kHz bandwidth and no FHSS, they're in violation of 47 CFR § 15.247.
    
    mtlynch
    
    Thanks for the heads up. Do you know what settings would comply with the law?
    
    mtset
    
    I use a bandwidth of 500kHz with spreading factor 12 to make up the link budget a little. The range is very poor.
    
    matheusmoreira
    
    I wonder what the privacy situation is. The end-to-end encryption is awesome but I assume your broadcasting location is visible to anyone in range. The automatic mesh network routing also prevents radio silence.
    
    duncaen
    
    meshcore by design is a lot more silent than meshtastic.
    
    If you mean the (GPS) coordinates by "broadcasting location", then this is configurable, you don't have to disclose your exact location or a location at all, "routing" does not use that. Otherwise, there is nothing on the protocol level to hide your identity or to avoid being triangulated, in that case the noise of meshtastic might even be better.
    
    Repeaters and "companions" (what you use as client) are separate firmware, the companion will never repeat any packets or advertise itself automatically.
    
    An automatic "route" is established once when you want to send a message or when the old "route" fails I think 3 times in a row. In that case it will will flood out a "path"/"trace" packet out that will be repeated by up to 64 repeaters, those repeaters will add their own "id" to the packet and when the intended recipient sees the packet it will send back an ack with all those repeaters in it and the first ack that comes back will be used as the new "route".