Hold on to your hats, HaLow is here

22 July 2026

I’ve been waiting a long time for WiFi HaLow (802.11ah) to show up. For the unaware, this is a standardised variant of WiFi using the 900 MHz ISM band to provide range over 1 km with a corresponding lower throughput—up to tens of Mbps.

The standard was published in 2017 but for a long time the only available hardware was pretty specialised and I stopped paying attention. Manufacturing has increased and around 18 months ago Heltec started selling a properly convenient USB/ethernet bridge device, the HT-HD01. Now that I know they exist, I have ordered four of them for mesh experiments. These units use a chip designed by Morse Micro, which I am proud to discover is an Australian company[1].

So what’s the big deal? Well, general consumers have had a pretty annoying range of communication technologies to choose from. We have regular fast WiFi, of course, with its tens-of-metres range. 2.4 GHz goes a bit farther than 5 GHz but competition for channels is fierce and microwave ovens are a natural predator. Bluetooth 5 Low Energy has its wonderful Coded PHY which lets you trade off bandwidth to get up to 1 km range, but it’s really very slow and you’ll be lucky to find an API for it outside of Android. Then there’s LoRa, which can work up to around 10 km, again with very low throughput. I’ll have more to say about LoRa shortly.

We’ve always been missing the happy middle. Now HaLow is here and that’s exactly what it offers. What can we do with it?

Of course, we’re not strictly limited to what we can buy off the shelf. There’s always amateur radio, the main downside of which is that you can only talk to other radio amateurs. For community/mesh networking this has some upsides—amateurs are generally well-behaved and the legal requirement to identify stations gives you out-of-band ways to deal with bad actors, which means you don’t have to solve every aspect of abuse handling in the protocol itself.

One thing that’s particularly cool about the HT-HD01 is that it supports 802.11s, a standard protocol for mesh networking. Here, stations can work together to form an encrypted mesh network. With the appropriate configuration your end devices can see a flat Ethernet segment, as if they were connected to the same switch, and the mesh routing is handled for you behind the scenes. That’s pretty neat.

Still, not everybody is satisfied with 802.11s as a multihop router. One of the most popular mesh-routing protocol families is called BATMAN, which is implemented in the Linux kernel as batman-adv. Using something like OpenMANET it happens that you can use 802.11s for all of its underlying connectivity and encryption but disable just the mesh forwarding, stacking batman-adv on top instead to cover that aspect.

I am curious to see how well these could work for a community WiFi deployment. It’s a bit of a harder challenge to get going. Even if the advertised 1–2 km range is realistic you need significant density to get a usable mesh. Within that usable mesh, though, suddenly so much is possible. Not just IRC: actual web pages, forums, email, images, PDFs, even VoIP or games if the latency is good enough. This is the kind of speed where it’s no longer just a poor backup to the “real internet”. If you rig it up in a sufficiently reliable and convenient manner it could be your first choice for local communications, not just something you reach for when Discord stops working.

And that’s my main gripe with MeshCore/Meshtastic, which are based on LoRa. They work for a low-volume text-based group chat containing only short messages. On the popular MeshCore “Mid” preset a 100-byte packet takes 0.55 seconds of airtime. That’s fine for what it is but it doesn’t really supplant anything. Good for an emergency or bushwalking; an idle curiosity when life is proceeding normally.

My other gripe with LoRa is that it’s a proprietary modulation scheme. The devices may be inexpensive but at the end of the day it’s using a patented and licensed technology. I would prefer to use an open standard where possible.

So I am looking forward very much to playing with these devices and seeing what they can do. If you live in Hobart and feel interested in doing some HaLow meshing, drop me an email.

  1. I was moved to take a peek at their careers page but, alas, all of their technical roles are on-site up in Sydney. That’s not happening. ↩︎

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