Meshtastic: Open-source, off-grid, hiking, climbing, GPS mesh communicator (opens in new tab)

I looked at the same thing for a project a couple years ago. We wound up writing a simple script using the TUN interface to send the IP packets over Digi's XBee radios (there's a 900MHz edition). Of course, sending all the packets through a userspace Python script was by no means efficient and the radios had only a 100K RF data rate to begin with, so the data rate was like 800bytes/second or something like that IIRC. Probably would be enough to cause some applications to timeout or give up on the network, but it was good enough for SSH and simple REST APIs.

There's no way 802.11ah will deliver 15Mbps, but if the standard is designed with that kind of data rate its gonna be a lot faster than what we were using (main reason is Wi-Fi is direct sequence spread spectrum while the XBees are frequency hopping, allowing a larger RF bandwidth). The one thing that is good about the XBees is they will support repeating messages for each other and they have a nice mesh functionality as opposed to Wi-Fi's client-AP model. Additionally, we were just using the small wire antenna on the XBee, which only outputs a fourth of the legal maximum power to begin with, limiting the range. The chipsets OP linked support the full 1 Watt output power.

As an aside, I also saw a serial modem using MURS that you could theoretically run a dialup program over. Also ridiculously expensive.

Yeah, this has been my experience too. Generally you use the frequency that has been legalised for use in the region you operate it in. I wonder if this automatically switches to the suitable frequency based off coordinates (when using a gps’d board) I’m sure it would be trivial to implement. Ah good ole opensource. This really is a great solution, riding around New Zealand the only solution is a SPOT tracker which charges like a wounded bull so I love that this is disrupting this space (and using clever tech - heck might throw one of these on the moto just to use it for security)

Right, it uses that in Europe as they don't have 900MHz. I think in the US there's some periodic use only requirements for 433.

I would buy one, as well as few naked one that I would solder myself. Those things could become very nifty. Solving problems that mesh-wifi can't quiet get right for organic deployment.

Intriguing. Power consumption might not be as big a problem on a portable device.

Han, that's fun.

Not very, but the point is that the necessity to set up an assembly line is a sticking point for adoption. You need to deploy a lot of these to make it useful so skill or time bottlenecks are a big disincentive.

I'm in mountain rescue and I'll second all of this. It's why we will set up repeaters, or station people as repeaters if we have enough people, but more often than not, we are out of radio communication for hours on end, despite all parties having the necessary equipment. More often than not, we'll use inReach texting to maintain comms.

But projects like this excite me for future directions. Sometimes when we've been in areas with cell phone coverage (some wilderness in SoCal has coverage), we will be able to see tracks in SARTopo update live from teams in the field. It's really cool when it works!

> I would recommend a SPOT or inReach as a your primary safety device with this as a (neat) backup. All they need is a line of sight to the sky which is much easier to do than either LoRA, VHF or HF.

I have quite a bit of experience with both, and wouldn't recommend either as a primary safety device. PLBs are far better.

SPOT is based on Globalstar, which leaves one without coverage in many areas. I also found it to be incredibly flaky even in areas of allegedly great coverage with a totally open sky.

inReach is vastly more reliable, and with global coverage, so if I was buying one for a (secondary) safety that would be the easy winner of the two. It also has the added benefit of bringing a convenience that PLBs don't, as one can grab weather updates and easily text others for information.

That said, it's not difficult to get into a situation where terrain makes quick satellite acquisition very difficult, and one could wait hours for a message to get out. PLBs are much more reliable in adverse situations (N-S slot canyons), have higher power output than satellite messengers, and are generally built to higher standards. They also don't require a monthly fee.

A legitimate PLB would give one more paths to a swift rescue, especially if SAR aircraft are already up and looking for you.

More info: https://www.backcountrychronicles.com/delorme-satellite-gps-...

I think that the mesh aspect of this would be a substantial improvement over VHF/HF radios. I'm sure I'm wrong, but I don't know of anyone that is running a mesh VHF or HF system in the mountains. I always carry my HAM when I'm out, just in case anyone else is, but obviously that's truly local communication and has the downsides that you mention.

With a strategically placed mesh network and some solar panels, you could potentially overcome a lot of the downsides of radio because you could target high areas, such as mountain peaks, to help bridge those obstructions.

I definitely don't disagree that the #1 safety device is a GPS/sat phone, but those are prohibitively expensive and most people don't have them. If we could get some solar powered radios along ridges, and a decent percentage of people carrying them, I think there could be a very comprehensive mesh network that would work for most needs. Bearspray is already pretty ubiquitous, I don't think it'd be that hard to get people to bring a $30 mesh radio with them as a routine thing.

Do you know if there's an open source PLB like the inReach?

Right, I was more thinking a mesh network solar operated to let people report their location and status across rough terrain. I may try making a few of these over the year for next hunting season, and place them in a mile or so radius from basecamp for the duration of my trip, anyways. That way we could split up but still maintain contact, get help if we shoot an elk, etc. We're definitely outside direct walkie-talkie range, and I'm in the only one in the group with a HAM, so this could be pretty useful.

That's similar to what I had, you also need a gps receiver, so your investing close to 650$, not great for when your dog smacks it on a rock or tree. The problem is in a mountainous area you need line of sight, so it became practically useless, I would constantly loose the signal. Combined with the battery life in cold weather... The only solution was a satellite connection or creating some sort of mesh coverage like the OP link suggests.

ps. Most dog trackers also do not work outside usa.

Having trouble figuring out the subscriptions costs on their website.

Codec2 is part of it but you need a lot more pieces on top(framing, modulation, etc). LoRA doesn't really have the bandwidth for Codec2(for a few reasons, mostly power and the way LoRA handles channel congestion).

M17[1] has been making really big strides in this space and really excited to start seeing a proper open hardware/open source digital radio stack.

[1] https://m17project.org/

Antennas and height make a huge difference. I’ve got a hop from my place to a friend that’s a little over 3km non line of sight (terrain/hill between). Can’t do that with the stock rubber ducky antennas, but with a swr meter tuned home made dipole antenna on a 4m pole on my roof it’s rock solid (using 433MHz, not sure if 815/915 would get that far).

Ah I see. Got too excited.

My current node is line of sight to the U.S. mountains south of Victoria, so if that's your location and you have line of sight, you can probably connect to me right now!

Can you elaborate on specifically what you have that's getting a couple miles? I tried out Meshtastic with a bog standard board exactly as it existed. I carried it down the road and found it got ~500m of reliable range with no obstructions. Has the software improved significantly, or is there different hardware to support getting multiple miles?

That's cool! Might try it out

I believe so, yes. But in all seriousness a line has to be drawn somewhere about open source'ness.

For example, there's a few ways to remediate that. My preferred is a reference Gnuradio flow that, with an SDR, allows for communication with their device network. Secondarily, open firmware would be good... but with open firmware still results in closed silicon (and not everyone has access to a fab!).

Closed source isn't always enough to run me away. Closed and closable interoperability does.