Text and position
Party positions, canned messages and check-ins over a channel with no subscription.
Platform · Off-grid communications
No tower. No satellite. Still linked.
Mesh radio is the channel that costs nothing per byte and works in the terrain that kills everything else. NavTrax speaks Meshtastic and MeshCore over 868 and 915 MHz, with per-message key rotation and dead-node repair inside two seconds.
01 / By the numbers
915MHzISM band868 MHz in Europe
240BFrame sizeFragmented, ordered, acknowledged per hop
<2sDead-node repairBeacon gap to first retry on a new path
6.4kmTypical hopTerrain-dependent; RSSI shown per link
02 / How it works
The mechanism, not the promise.
- Per-message keys
- Rotated every message, giving forward secrecy rather than a shared channel key that leaks the whole history when one node is captured.
- Fragmentation
- Payloads split into 240-byte frames, ordered, with acknowledgment per hop rather than end to end only.
- Hop rerouting
- A missing acknowledgment within two seconds marks the node down and recomputes the path. The message does not wait for a human to notice.
- Beacon cloaking
- Jittered intervals to reduce the RF signature, which matters more the further from recreation you get.
- Bridge to IP
- Any node with cellular or satellite becomes the group’s gateway. The bridge is a role, not a device you have to designate.
03 / Capabilities
What you actually get.
Store and forward
Unattended relay caches hold traffic for a bounded window and report what they are still holding.
Sync transport
The mesh is a first-class sync channel, not a chat sideline. Trip edits travel over it as compacted digests.
SOS flood
Hop-limited flood with per-hop acknowledgment, as the second link in the escalation chain.
Link quality visible
RSSI and hop count per peer, so a marginal link is a number rather than a surprise.
Jam and spoof response
Channel hop, mode change and dead-reckoning fallback when the RF environment turns hostile.
04 / Specification
| Property | Value | Note |
|---|---|---|
| Bands | 868 / 915 MHz ISM | Region-dependent |
| Frame | 240 bytes | Fragmented and ordered |
| Key rotation | Per message | Forward secrecy |
| Repair time | < 2 s | Beacon gap to retry |
| Stacks | Meshtastic, MeshCore | Off-the-shelf hardware |
| Cost per byte | None | The reason it matters |
05 / Process
Traced, node by node.
Every node in this graph names the file it came from, so the diagram can be audited against the codebase rather than taken on trust.
The channel that costs nothing.
Mesh radio is on Pro. Self-healing behavior and cloaking are documented on the defense pages.