Mesh Radio Networks
Should "prepared civilians" build a mesh radio network?
A Meshtastic radio antenna with the waterproof case that will eventually house it outdoors
Should Prepared Civilians Use Mesh Radio Networks?
Are mesh radio networks useful for prepared civilians? The answer, as with so many things, is “it depends.” Situational awareness tools like TAK[i] depend on mesh connectivity. If you plan to use TAK or a similar tool for your team or organization, then a mesh radio network is useful for you. If voice communications satisfies your requirements, then mesh radio networks may be more than is required.
What is a “mesh radio network?” Let us start at the beginning by reviewing the meaning of the word “mesh.” Like many words in English, mesh is “function overloaded.”[ii] In simple language, it has multiple meanings.
The meaning of mesh that is useful for radio networks is “material like a net with spaces in it, made from wire, plastic, or thread.”[iii]
A mesh radio network is a net of radios with spaces in it where the connections are radio waves rather than “wire, plastic, or thread.”
Mesh radio networks extend the communications range of the radio network. Each antenna has a repeater connected to it. The repeater is a small computer with its own radio receiver and transmitter. The repeater rebroadcasts (repeats) everything it hears. The repeater network described in the earlier article had one repeater at the center of the network. Mesh networks have many repeaters.
The repeater network in the earlier article depended on height above ground and transmitted power to extend the network. Mesh radio networks rely on repeaters (with antennas) that are relatively close to each other to relay the broadcast to radios that are farther away.
Mesh radio networks, at least in their current state, are primarily for digital device to digital device communications. Audio messages can be transmitted but the technology is a little bit of a “force fit” for audio communications. It is a digital medium and offers more communications options than a pure voice network.
The picture below shows how a mesh radio network might relay messages. Team Member 1 (TM 1 at the lower right corner) is out of range of everyone except Team Member 2 (TM2). TM2 repeats all messages from TM1 and several other radios hear the message. Each of them repeats it until Team Member X (TMX at top left) and all other stations hear the message. To limit network traffic, you can set a limit for how many times a message is repeated. In this case the message must be repeated at least three times to get to TMX. The limit is set in a parameter called “Max Hops.” In the network shown above, “Max Hops =3” lets every radio hear every message.
In the next article, we’ll dive into Meshtastic. The first mesh radio network that I build and test will be a Meshtastic network. Meshtastic is a DIY approach to building a mesh network. It is fairly technical but well within the reach of a diligent prepared civilian.
The picture at the beginning of this article shows a Meshtastic radio that I built. You can see the waterproof case with solar panel that will eventually house the radio at the top and bottom in the picture. The center part is the Meshtastic radio built on a (temporary) clear acrylic stand/housing. I’ll dive into the radio hardware in the next post.
The steps in building a Meshtastic network are: procure the hardware, build the radios, install and configure the software, and then test it using devices that can communicate with Meshtastic. Each step has decisions and trade-offs. I’ll devote at least one post to each step.
After Meshtastic, I hope to get GoTenna to loan me some of their mesh radio antennas. After that, it’s on to really high function mesh networks.
[i] https://tak.gov/products
[ii] https://en.wikipedia.org/wiki/Function_overloading
[iii] https://dictionary.cambridge.org/dictionary/english/mesh