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Off-grid and emergency

A LoRa-only mesh for situations where there's no internet, no cell service, and no shared infrastructure: disaster response, expeditions, remote worksites, off-grid communities. This page is the practical baseline. Everything below works on battery power and stays within the radio band.

When to use this​

Reach for an off-grid mesh when one of these is true:

  • Cellular and internet are down or never existed (storm, blackout, backcountry).
  • You need group messaging that survives without any provider.
  • You want a private radio channel that won't be confused by other meshes nearby.

This is messaging-grade comms: text, position, short status. LoRa is not a video link. Don't plan on streaming anything. Plan on sending sentences.

Hardware​

Minimum viable off-grid kit:

  • One handheld per person. Either a Ratdeck or rsCardputer for standalone LoRa messaging, or a phone/laptop running Ratspeak connected to a separate RNode over BLE, USB where the platform allows it, or a local RNode TCP bridge if your field kit supplies its own LAN. Ratdeck has BLE bridge support; rsCardputer can be used as a standalone handheld or booted into RNode mode for BLE/USB host use.
  • Optional always-on transport node. A Raspberry Pi + RNode + battery + small solar panel, sited high. One transport node can stitch together handhelds that can't directly hear each other.

You don't need IP, you don't need Wi-Fi, you don't need a backbone. The only exception: if you want to bridge a single laptop into the mesh in the field, a Ratdeck can run as a Wi-Fi access point and the laptop joins it. That's local-only, no upstream internet involved. Treat that AP bridge as experimental and test it before the deployment.

Power budget​

LoRa is a low-power protocol, but TX bursts still cost real current. Sensible numbers to plan around:

  • RNode TX draw: ~100-200 mA on transmit, much lower idle/RX. A handheld goes a full day on its internal pack with normal use.
  • Always-on transport node: a 20 W solar panel + 100 Wh battery keeps a Pi + RNode running 24/7 in normal weather. In persistent overcast, double the panel or accept a daily downtime window.
  • Carry a spare battery pack for handhelds. Two cheap USB-C power banks are worth more than one expensive one — redundancy beats capacity.

If the transport node is on a tower or roof, mount the panel where you can reach it for cleaning. Snow and dust kill more solar deployments than hardware failure.

Picking a LoRa preset​

Reticulum exposes the standard RNode presets. For an off-grid group, start here:

  • Long Fast (SF11, BW250): good baseline. Reasonable range, tolerable throughput for short messages.
  • Long Moderate (SF11, BW125): drop to this if signal is marginal. Narrower bandwidth = more range, but every message takes noticeably longer to send.

Higher spreading factor means longer range and slower throughput. Don't switch presets mid-deployment unless every node switches together — mismatched presets won't hear each other at all. Pick one preset per group and write it on the inside of the case if you have to.

Frequency and regs​

Use the right ISM band for where you are:

  • 915 MHz — Americas, Australia
  • 868 MHz — Europe
  • 923 MHz — most of Asia

You're responsible for staying within local regulations on power, duty cycle, and band edges. Don't transmit on bands that need a license unless you actually have one. If you're crossing borders during the deployment, plan the radio config for each leg before you leave.

Setting up a transport node​

A transport node is a node that relays for others. On the always-on Pi, add this to the rsReticulum config at ~/.rsReticulum/config.

[reticulum]
  enable_transport = yes

That single setting turns the node into a relay. Without it, the node only handles its own traffic. With it, handhelds out of direct earshot of each other can still talk through the relay. Site the node high — antenna height beats transmit power every time.

Confirm the transport node is announced and being heard before you scatter. Have each handheld send a test message to the others. If the message routes through the transport node, you're set.

Locking the mesh with IFAC​

Use IFAC even in emergencies. Especially in emergencies. IFAC stops random unrelated mesh nodes — somebody's hobby gateway in the next valley — from polluting your routing tables. Every node in your group sets the same network_name and passphrase on the LoRa interface in the node's Reticulum config:

[interfaces]
  [[Field LoRa]]
    type = RNodeInterface
    port = /dev/ttyUSB0
    network_name = your-group-name
    passphrase = use-a-strong-shared-secret-here

Both fields must match exactly across every node. Treat the passphrase like a shared key: write it down, hand it out in person before deployment, don't post it. If somebody loses their handheld, rotate the passphrase across the group.

Field tips​

A few things that come up every real deployment:

  • Pre-share contacts before the emergency. Trade announces and confirm pairs while you still have power and time. In a crisis, nobody wants to debug destination hashes.
  • Test the mesh in good weather. Walk the perimeter, check fringe coverage, find the dead spots before they matter. Note where you needed to drop to Long Moderate.
  • Label every device. A piece of tape with the node name and owner saves arguments later.
  • Don't expect interactive throughput. Compose messages, send, move on. Treating LoRa like SMS works. Treating it like chat doesn't.
  • Keep one node off when not in use. Rotating which handheld is powered up extends collective battery life across a multi-day event.
  • Antennas matter more than radios. A clear sky and a good vertical antenna beat a high-end RNode buried in a backpack.

When the grid comes back, your mesh keeps working. That's the point.