Mesh radio is a fun way to chat with radio nerds in your area. Not a serious infrastructure.
Meshtastic should be the obvious answer for this but in my limited experience the app(s) and code are buggy on even the most typical hardware. Wish it wasn’t the case but it is.
If you're talking about a few miles/KMs between nodes, plain old LoRaWAN might be more than sufficient, esp. for the sensor use case. The nice thing about using LoRaWAN is that's it's literally providing an IPv6 overlay so you can run e.g. MQTT or a text-based messaging protocol designed for regular TCP/IP use. UDP is preferable to avoid frequent session resets and keepalive traffic chewing up your available bandwidth.
Meshtastic and MeshCore can theoretically provide "infinite" range so long as there are peers between the nodes you want to connect. Theoretically, mobile peers can also serve as store-and-forward nodes so that reachability doesn't need to be constant, just frequent enough to handle the messaging you want to do.
I would absolutely not rely on either for a safety-critical application, though. If you want emergency comms in case something happens while you're out on the mountain, use a satellite communicator. There are a ton of these marketed for outdoor/portable use, and they have much more robust "SOS" capabilities (up to and including direct dispatch of search-and-rescue).
Of course, for real emergencies I have a Garmin SOS device. It would just be "nice" to have something for local 2-5 km communication that doesn't need a clear view of sky, works partially underground, etc. GMRS is "fine" but from a physics perspective a digital signal with Chirp encoding should go further and be more reliable.
Seems like JS8Call or Packet radio might more in line with what I want. It's just surprising that something like Meshtastic hasn't replaced them.
From what I recall, meshcore de duplication only tracks like the last 256 messages so that could quickly fail to de duplicate.
I think people need to think more about what the actual scenario they have in mind is because it seems most people think of mesh radio as some backup for the government shutting the internet down. When in reality it’s almost useless for that since it’s so easy to jam or flood mesh radio.
Not LORA.
The mesh networks are dealing with, by definition, a sparse and widely distributed set of devices which are independently configured and controlled, and in their current widely available form are only dealing with terrestrial communication. Without that point of centralisation you would need to focus on targetted regional jamming, as from a practical standpoint you cannot perform wideband RF jamming over an entire country - signal jammers don't scale that well, and geographic features come into play. As an example you might effectively block mesh networks from operating reliably in a given city, but if people were to move outside of that area then the mesh would operate again. Geography is both a strength and a weakness here: a mountain range will impede direct communication with someone on the other side, but it will also have the same effect on jammers which will vastly increase the cost to deploy them in a ubiquitous fashion.
Jamming is done in military scenarios too, but in that case it’s limited by the fact that a jammer is a big transmitter painting itself with a big sign that says “fire missile here.” Civilian mesh doesn’t have that fallback.
Also, it might not be jamming. It might be that whoever is operating the satellites at the time denies access unless you enable inspection, and then sells that info to somebody who would hurt you--or whatever other can't-trust-the-middleman dystopia you care to imagine.
I've been tinkering with the tech to make city-wide flrc meshes joined together over the internet, my estimates are that it should be at least able to support thousands of users per region.
