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PathBe useful when the weather turns· step 5 of 5
🚨 EmComm· intermediate

Mesh in a grid-down

What Meshtastic and MeshCore can and can't do when the towers are dark - and how to set up so they still can.

2 min readUpdated 3w1 contributor

Cellular fails in two ways in a disaster: the towers lose power or backhaul, or they stay up and collapse under load. LoRa mesh is immune to both. A $30 radio in your pocket talks to another one across town by bouncing off rooftop nodes that nobody has to maintain in the moment. That's the promise. Here's the reality.

What it does well

  • Short text, city-wide. "We're OK, at Mom's." "Tree on Elm blocking road." A message needs no tower, no account, no payment.
  • Position. Nodes with GPS share where they are. A family group with nodes knows where everyone is without asking.
  • Days on a battery. A companion node on an 18650 cell runs for days. A rooftop router on a small solar panel runs indefinitely.
  • Store-and-forward on MeshCore. Room servers hold messages until your companion is back in range - a message board that survives you being offline.

What it doesn't

  • No photos, no voice, no web. Text, a couple of hundred characters at a time.
  • No guarantee of delivery. Acks tell you it arrived; no ack means try again.
  • Range is line-of-sight-ish. Hills, buildings and trees eat it. A node in a window beats one in a pocket; a node on a roof beats both.
  • Throughput is tiny. If everyone talks at once, nobody gets through. Keep it short and infrequent.

Set up before, not during

  1. Get on the local mesh now. Your state hub's map shows the nodes near you. Add yours, learn who's around, send a message on a normal Tuesday.
  2. Agree a family channel. A private Meshtastic channel with a shared key, or a MeshCore group, so family traffic doesn't compete with the public channel.
  3. Put one node high. A router/repeater on a roof or a tall tree with a solar panel is the single thing that makes a neighbourhood mesh work. Check the state group - someone may already cover you.
  4. Weather channel. Some meshes run a weather bot or a dedicated channel that carries NWS alerts over the air. If yours does, join it; if it doesn't, the state MeshCore or Meshtastic group is where to ask.
  5. Charge it. A companion on a dead battery is a paperweight. Same power bank as your phone.

Bridging to the wider world

The mesh reaches across town; radio reaches across the state. The useful pattern is a person with both: a ham or GMRS operator who also runs a node and relays what matters. If that's you, say so in your state group. If it isn't, find out who it is before the sirens.

Meshtastic or MeshCore?

Both work. Meshtastic has the bigger install base and the most rooftop nodes in most cities; MeshCore's roles (repeaters that relay, room servers that store, companions that don't flood) hold up better under load. Plenty of people carry one of each. The Meshtastic and MeshCore paths get you from a box to a first message in an afternoon.