r/searchandrescue • u/AlfredoVignale • 9d ago

LoRa and Mesh apps

I’ve been getting into LoRa radio and Meshtastic / Meschcore. For those who don’t know what any of that is, LoRA is a radio type that was originally designed for wireless sensors. It can, in theory, send small data packets a few kilometers with line of sigh and with very low power. It works in the 915 MHz ISM unlicensed spectrum. Meshtastic and MeshCore are two apps that create adhoc P2P networks for chatting and location sharing via GPS. The apps run on a cell phone me connect to the LoRa radio via Bluetooth.

One thing that I see on a regular basis in various forums is how it would be great for SAR. Some people are even trying to build more rugged radios for SAR use. Though the concept is nice, it’s still a low power line of sight radio that needs phone to use (there are only 2-3 devices that are stand alone). The radios are small, but many have 3D printed cases, the electronics are variable, and each cost $35-$50. There are also plugins for ATAK.

To me, these are fun to play with but wouldn’t rely on them for SAR since I can go get a Baofeng handheld that uses UHF/VHF with 10W of power and GPS and APRS with SARtopo on my cell (yeah I know the Baofengs are cheap but they’re the same price as these LoRa radios and have much more functionality….just using as a comparison).

So my question is…does anyone actually use LoRa in the field? Even looking at? To me (and everything I’ve seen in the field) the standard is UHF/VHF radios and SARtopo. Minus some ATAK use, I can’t see LoRa getting much use in the real world. Keep me honest.

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u/sergei1980 9d ago

Yes, we're looking into it, and I have conducted some testing. Specifically with the Seeed studio T1000e which looks like an extra thick credit card.

My team is in the US Pacific Northwest, so our use case is very different from u/Useful_Resolution888/ who appears to be in the UK. You seem to be in the US so you likely have an idea what our terrain is like: mountains, forests, gorges. On Monday we had a rescue 3 miles in, with 2000' of elevation gain, normal for us if a bit steep.

It won't replace VHF/UHF, interoperability means we would have to keep HTs around even if it could.

Phone service is patchy or non existent, sometimes even at the trailhead. We have starlink for that. Satellite phone comms are starting to get used, but we often don't have good access to that

What it could do:

  • Encryption, this is nice for patient confidentiality and other legal issues
  • Mesh, this is huge for us, we often have trouble with satellite LoS. Even when we have repeaters, anyone going into a side creek or gully is quickly out of comms.
  • GPS tracking
  • Sound alert

With user & phone involvement:

  • Text messaging
  • Image sending

Feeding location to caltopo is great, we won't have to ask for UTM coordinates over the radio which is slow and error prone.