Meshtastic
What is Meshtastic?
Meshtastic is an open-source platform for off-grid text messaging, location sharing, and telemetry over LoRa radio. Nodes form a mesh: each device can relay traffic for others, so coverage grows as more people participate. Phones and laptops connect to a small radio over Bluetooth or Wi-Fi—no cellular network required for local chat and maps.
When is it useful?
Meshtastic shines when infrastructure is thin, congested, or unavailable: after storms, in remote areas, during large events, or simply as a resilient “side channel” for community coordination. Messages are low-bandwidth and optimized for range rather than streaming—ideal for check-ins, situational awareness, and lightweight coordination alongside amateur radio voice and digital modes.
Who uses it?
Typical users include hikers, sailors, emergency-preparedness groups, clubs, and neighborhoods experimenting with community-owned networks. Many teams overlap with amateur radio values: self-reliance, experimentation, and public service—without replacing traditional ham operations.
CARS mesh project
The Cayman Amateur Radio Society is rolling out an island-wide Meshtastic network, starting on the Long Fast channel plan so early nodes stay compatible and the mesh can grow predictably.
Join the CARS mesh
To talk with the rest of us, configure your node for Long Range - Fast on LoRa and point MQTT at the Cayman LongFast topic. Internet-connected nodes then share traffic with the island mesh via the public Meshtastic broker.
Screenshots below are from the iOS Meshtastic app (Settings → LoRa Config / MQTT Config). Android menus use the same values under Module / Radio config.
LoRa settings
| Setting | Value |
|---|---|
| Region | United States |
| Use Preset | On |
| Presets | Long Range - Fast |
| Ignore MQTT | Off |
| Ok to MQTT | On |
| Transmit Enabled | On |
| Coding Rate | Preset Default (4/5) |
| Follow Preset Coding Rate | On |
Region United States is the correct 915 MHz ISM plan for Cayman—it is a frequency plan, not a claim that you are operating in the US.
MQTT settings
Enable the MQTT module, then set:
| Setting | Value |
|---|---|
| Root Topic | msh/KY/LongFast |
| Address | mqtt.meshtastic.org |
| TLS Enabled | On |
Also enable Uplink and Downlink on your Primary channel (Channels → Primary). Without both, the node will not exchange traffic with the MQTT mesh.
The root topic is easy to get wrong. The app may suggest nearby topics like msh/US/George… because Region is United States and GPS places you near Georgetown. Use msh/KY/LongFast instead—KY is Cayman, and that is the topic the CARS mesh uses today.
Turn TLS Enabled on — the public broker requires it (see the app helper text). If your screen still shows TLS off, flip it before saving.
Host a node
We want to work with you. The best sites are often roofs or second-floor windows with a clear view of the horizon—each well-placed node materially extends coverage and resilience for everyone. If you can host a solar- or mains-powered node, or want help planning an install, please contact the club and mention Meshtastic in your message.
Meshtastic® is a registered trademark of Meshtastic LLC. CARS is an independent community group using the open Meshtastic firmware and ecosystem.