I’ve spent some time over the last year or so playing with mesh networking. It’s an exciting technology that I think will really enhance the amateur radio hobby.
The interesting thing from a ham perspective is that the lower half of the Wi-Fi portion of the spectrum overlaps the amateur service 2.4GHz allocation. This means we hams can use power levels and antenna gains available to us (in the U.S.) under FCC Part 97 rules.
There’s a project you may already be familiar with called Broadband Hamnet that developed and maintains firmware for mesh nodes. It can be installed on some (but not all) varieties of Linksys WRT54G Wi-Fi routers and a variety of Wi-Fi devices from Ubiquiti Networking. I have personal experience with both Linksys routers and Ubiquiti NanoStation M2 Loco devices. The Linksys routers are nice because the have two detachable antennas, so you could run high gain directional antennas from one or both antenna ports. They are not weatherproof, though, so to install them outdoors, you need an enclosure. The Ubiquiti devices are made for outdoor use. Installation instructions and other documentation can be found at the Broadband Hamnet website.
I have also set up a number of nodes on Raspberry Pi computers. In fact, the Raspberry Pi I wrote about recently is set up as a mesh node, along with a Raspberry Pi Zero I was lucky enough to acquire. The software and installation instructions can be found at the HSMM-Pi github repository. I have found this setup to be a little bit fiddly, and the fiddliness is usually related to the particular Wi-Fi adapter used with the Raspberry Pi. If you have trouble getting the Pi to see the other nodes in your network, try plugging the adapter into a powered USB hub, or try a different adapter. That seems to solve about 90% of the communication issues I’ve encountered. The other 10% are because I’ve entered the network SSID incorrectly on the HSMM-Pi admin page. If you only have Pi nodes on your network, the SSID can be whatever you want (as long as they are all identical). If you have Linksys or Ubiquiti devices mixed in, the SSID has to be Broadband-Hamnet-20-v3.
The advantage, in my view, of the Raspberry Pi as a node is that you have a reasonably capable computer and mesh node all in one tiny package. With the Linksys or Ubiquiti devices, the capacity to host services on them is pretty limited; you need a separate computer connected via Ethernet cable to host and share services that make the mesh actually useful. I’ll have another post about a few of those services I find useful or interesting in the near future, but the bottom line is that anything you could offer on the Internet, you can offer on a mesh net. This has obvious potential to be a huge asset for emergency communications.
Have you dabbled in mesh networking? tell me about your experiences in the comments.