Technology

That's pretty much exactly what they are. Text message in walkie-talkies. With the added benefit that if your friend can't hear you, but another friend is in between, your message automatically gets relayed through their walkie-talkie.

Sucks you can’t charge it and have to instead go to a central bank to exchange minted coins for notes that you can exchange for the commodity that is the radio.

It is cool! The barrier to entry is relatively low. The only thing to really worry about is:

1. What band/frequency is appropriate for you country.
2. Are there others around to which you can connect?

If there's not a lot of people around it's not the end of the world. Nodes can connect over the Internet via MQTT servers. Yes, this defeats the purpose of having an offline/decentralized communication platform, but it is a good stop gap until more nodes are put up.

Here's a sample of what I can see in a somewhat large-ish Midwest City in the US (there's about 63 nodes I can reach by hopping through relays).

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It allows us to make a mesh network (interconnected nodes where you can contact a node even if it's not in range for you, by using other nodes) with Lora radio devices. Lora is slow but has long range. I think it works better when you have line of sight, like if someone can put a node on a mountain, it would help everyone.

I think people might have sent audio with it but it's mostly useful for text messages. It could be useful if the Internet is down, maybe, but it's more like a toy.

Sure, but they could at least put that in the title as well so people who are familiar w/ it don't need to click through.

Yeah this is not SMS! Its probably text that looks like:
¥¢¥^=¶√•€¢√°=¶}{°÷™π^™¥π¥¥° °{}}∆∆×÷°%^¢¢°{]]×=%π¥®√™^%÷

Exactly. I was hyped because I'd like to send and receive SMS w/o a mobile phone. I was hoping someone implemented the protocol so I could integrate it into my desktop, the "no wi-fi or cell service" was merely a bonus.

But no, this is just a way to communicate over a different radio protocol than mobile phone standards.

Theoretically you can get 50 ish miles or more with line of sight. In practice, you can get around 10 ish with repeaters. With around 30 devices, our city has effective coverage.

You also have options to use MQTT if you want to make sure a message gets through. But that requires an internet connection.

I'm running about 1w per device ATM.

So yeah it sips energy. There's a lot of nodes in the mountains that are solar powered. They work.

Easiest and least expensive are a little different, so I'll talk briefly about both.

The easiest is to go on Etsy and search for Meshtastic. You will find plenty of people who will build you a ready-to-go unit, both individual radios and solar-powered repeaters. (If you plan to put your repeater somewhere with power you can use any radio as a repeater, just put a good antenna on it.) Pre-built units start at around $60 and can go up into the hundreds, but $60 to $90 will get you a great personal radio.

The least expensive is to order a kit from one of the many companies that sell them. If the kit does not come with a case, check Etsy for cases that match your kit. Most kits do not require soldering, you just have to plug in various cables and connectors, then fit everything into the case. Some actually come fully assembled. This approach generally costs somewhere between half and two-thirds of what a pre-built setup will run. Kits start as low as $10, although most or $20 to $40, and cases are mostly $20 to $35.

One of the harder parts is to figure out which radio kit you want, but there are just two major types. Those built around the ESP32 processor tend to be a little less expensive and offer the option of WiFi, but they have a much shorter battery life. Those built around the nRF52 processor cost a little more, do not offer WiFi, but have nearly 10 times the battery life. WiFi is only used in a few specific cases, usually by repeaters and not personal units, so you may well not need it. Battery life is not usually an issue for personal radios, since nearly all of them will go for a full day between charges, but sometimes you may want more than that. Stand-alone repeaters that run off solar panels are almost all based on the nRF52 because of the battery life.

The most common starter radios are based on the Heltec V3 kit, which is based on the ESP32. It has been around a long time, it is relatively inexpensive, and it can do pretty much everything. The only downside is battery life, which may or may not matter to you. Unless that's a concern, you can't go wrong with a V3. My personal favorite is the T114 kit, also from Heltec, which is based on the nRF52. It is much like the V3, but without WiFi and with much better battery life.

I would wait until you've played with a personal radio before buying a repeater. Every Meshtastic radio acts as a repeater, so you don't necessarily need a dedicated repeated. Find out how many nodes are in your area and what kind of coverage you get. If there aren't many nodes, or distance is limited, you can consider a dedicated repeater.

Basically, a repeater is just a node with a good location that's put in a good location, up as high as possible. Because Meshtastic radios use very little power, it is practical to make completely self-sufficient solar repeater units that never require charging. You can put one of those on your roof, up in a tree, or on top of a nearby hill or mountain, without having to worry about regularly climbing back up there.

I strongly recommend that you go to meshtastic.org and read through the Getting Started documentation. It provides a lot more detail (and less personal opinion). And check out the Meshtastic communities on Lemmy. Have fun!