[2024-06-01] OFF-GRID COMMS WITH MESHTASTIC
Meshtastic is an off-grid communication platform that carries encrypted messages over 915mhz (915mhz in US; other regions use different frequencies) using the LoRa protocol.. That means that you can send messages even if you have no access to a cellphone tower, WiFi, or any other infrastructure-dependant methods of communication. A message intended for one user can also bounce off other devices that are part of the same mesh.
Why?
Imagine a scenario where WiFi or cell phone towers are unavailable. During some large events like music festivals sometimes cell phone towers become overloaded and attendees have difficulties communicating over the network.
Even more concerning imagine a situation where you cannot depend on the local infrastructure either due to censorship or due to natural disasters.
Meshtastic also has the option to use a callsign if you’re a registered radio operator, but does not require it. If used with a callsign, then [legally] communications cannot be encrypted but you can transmit at more than 2 watts of power. You can communicate from one meshtastic device to another up to 254km away (this is the current record over absolute perfect conditions. You will not get this far.), but any device can also work as a repeater or a router. This means that with a big enough network (or mesh) of devices you can reach much farther.
Meshtastic can be a decent resilient, decentralized, private and secure (*read Issues below) option for communications.
How?
The cheapest and easiest Meshtastic setup I’ve used (so far) requires a Heltec V3 LoRa development board, some power source and an android phone. The Heltec V3 LoRa board comes with an ESP32-S3, USB C, a PH2.0A battery plug, battery charging controller (only charges if the cable used is a USB C to USB A. Will not charge on USB C to USB C cables; not sure why), and an SSD1306 OLED display. Flashing Meshtastic is very simple.. Once flashed, connect it to your phone via Bluetooth using the official Meshtastic app.
Your Heltec LoRa board will need power. You can either connect it to a USB power bank, or you can buy a battery separately. I used a generic 3.7V LiPo battery with a PH2.0A plug off amazon.
Once the board is flashed and connected to your phone via bluetooth, you can either use the default channel or create a new one. As far as I can tell, you can only be part of one network at once.
To achieve a longer range some users install repeater devices in high places. Some devices (not the Heltec mentioned above) are so low power that they can be left unattended with nothing but a solar panel and a waterproof case.
Issues
There’s a few issues that I’d encourage any users to consider.
- Meshtastic is FOSS and distributed under the GNU General Public License v3.0 but LoRa is proprietary. However, it is only a “physical proprietary radio communication technique” and not necessarily software.
- If you want to broadcast with more than 2 watts of power you’ll need to be a licensed radio operator, which means you can no longer use encryption.
- LoRa has a very distinct waveform. I don't understand well enough how this works, but it means that someone could potentially recognize LoRa device's broadcasts from other signals. See https://www.youtube.com/watch?v=dxYY097QNs0.
- Encryption should be good enough for most users’ threat models but you should at the very least read the docs overview on encryption: https://meshtastic.org/docs/overview/encryption/.
- In my testing any kind of physical barrier lowers the range dramatically. Line of sight is ideal.
Meshtastic is a really cool technology. I personally use it when I’m outdoors, camping or hiking. It’s worth a look for anyone interested in comms, prepping, radio, or anyone who needs some way to communicate off grid without a radio license.
- gousse