LoRa Mesh 101

General Guides

What LoRa is

LoRa is a radio modulation scheme (chirp spread spectrum, from Semtech) that trades speed for range and sensitivity. It runs in license-free sub-GHz bands and a receiver can decode signals several dB below the noise floor at the slower settings. The cost is bandwidth: useful data rates are measured in single-digit kilobits per second, not megabits.

That budget buys you short text messages and telemetry. Payloads are a couple hundred bytes. Nobody is browsing the web over this, and that is the point: tiny messages travel a long way on very little power.

What "mesh" means here

A single LoRa link is point to point. A mesh forms when nodes rebroadcast each other's packets, so a message hops around hills, buildings, and dead spots. Your handheld only needs to reach one node with a good perch; the network does the rest. Every packet carries a hop limit so it cannot circulate forever.

How Meshtastic routes

Meshtastic uses managed flooding. When a node hears a packet it has not seen before, it rebroadcasts it, with timing tricks so that nodes hearing a weaker signal (probably farther away) rebroadcast first. The default hop limit is 3, the maximum is 7. Most nodes participate in relaying by default, and dedicated ROUTER role nodes get rebroadcast priority.

Flooding is simple and robust: no routes to learn, no state to go stale. The tradeoff is airtime. Every relayed packet occupies the channel everywhere it is heard, so very dense meshes (hundreds of nodes in one city) can congest, which is why Meshtastic documentation pushes settings discipline and role hygiene in large deployments.

How MeshCore routes

MeshCore splits the network into roles. Companion nodes (the one paired to your phone) do not relay at all. Dedicated repeaters do the forwarding, and room servers host shared channels with store-and-forward: post while a member is offline and the room holds the message until they reconnect. Discovery uses flooding, but direct messages then follow a learned path through specific repeaters rather than flooding the whole mesh.

The result is less airtime per message and predictable coverage, at the cost of needing somebody to actually place repeaters well. A MeshCore mesh is more like community infrastructure than an ad hoc swarm.

So which one?

Meshtastic has the larger community, more mapped nodes, and mature Android and iOS apps, so in most areas it is the network that already exists. MeshCore's routing spends less airtime and its store-and-forward rooms cover offline delivery, but you inherit the repeater-placement work. The firmware decision is not permanent: most boards flash either one in minutes, and many people run both on different boards. Check the node maps for your area and see who is actually out there.