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LoRa Scanner: a MeshCore preset, and its packets read

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- MeshCore joins the presets (EU/UK Narrow: 869.618 MHz, 62.5 kHz, SF8,
  CR 4/8, sync 0x12), after the Meshtastic ones so stored choices keep
  their number; `lora preset MeshCore` on the console
- lib/meshcore reads what MeshCore sends in clear: header, path, and a
  node's advert (name, kind, key, position)
- the list row, the details, a Capture's viewer and the console echo read
  a packet by the sync word it was received on
- the bandwidth is printed as 62.5, not 62

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk
This commit is contained in:
twisla
2026-10-09 20:30:29 +02:00
co-authored by Claude Opus 5.5
parent 861a60b73d
commit 8ba41f72b6
23 changed files with 622 additions and 62 deletions
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site/content/guide/lora-scanner.md
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@@ -13,14 +13,38 @@ The Scanner uses the **Cap LoRa-1262**. It **never transmits**: it listens and s
The first view lists what the radio hears, newest first: the time, the RSSI (signal strength, in dBm) and the SNR (signal over noise, in dB). For a **Meshtastic** packet it also shows the sender and the receiver (the last four hex digits of their numbers) and the number of hops.
For a **MeshCore** packet it shows what the packet is, who it concerns and how many repeaters are in its path:
| Row | Is |
|---|---|
| `adv Brussels-R1 2h` | A node saying who it is, by its name, heard through 2 repeaters |
| `txt a3>7f` | A private message from the node whose key starts with `a3` to the one starting with `7f` (`req`, `rsp` and `path` look the same) |
| `chan #11 1h` | A message on a channel; `#11` is the channel's byte, and `11` is the public channel's |
| `ack`, `anon`, `trace`, `ctl` | An acknowledgement, a login, a trace, a discovery |
| Key | Does |
|---|---|
| <kbd>Enter</kbd> | The details of a packet: the Meshtastic header, which is never encrypted, and a hex dump |
| <kbd>p</kbd> | Picks one of the 7 Meshtastic presets allowed in EU868 (LongFast by default) |
| <kbd>Enter</kbd> | The details of a packet: what is never encrypted (below), and a hex dump |
| <kbd>p</kbd> | Picks what to listen to: one of the 7 Meshtastic presets allowed in EU868 (LongFast by default), or **MeshCore** |
| <kbd>c</kbd> | Starts or stops a **capture** |
| <kbd>Tab</kbd> | Switches to the Sweep |
The Scanner shows the header and the bytes; it does not decrypt the message itself, which Meshtastic encrypts with the channel's key.
The Scanner shows the header and the bytes; it does not decrypt the message itself, which Meshtastic and MeshCore both encrypt.
**One network at a time.** The radio listens on one frequency with one setting, and the two networks share neither: on a Meshtastic preset no MeshCore packet is heard, and the other way round.
### MeshCore
The **MeshCore** preset is the setting its networks use in Europe, "EU/UK (Narrow)": 869.618 MHz, 62.5 kHz wide, SF8, coding rate 4/8. A network set up differently needs `lora custom` in the [Shell](/guide/shell/).
<kbd>Enter</kbd> on a MeshCore packet shows:
- what it is and how it travels: **flood** (every repeater passes it on, and adds itself to the path) or **direct** (it carries the route to follow);
- the path, one repeater a hop, each named by the first byte of its key;
- for an **advert**, which is signed and never encrypted: the node's name, its kind (chat node, repeater, room server, sensor), the start of its key, and its position if it gives one;
- for a message: the first byte of the sender's and the receiver's keys, or the channel's byte, and how many bytes are encrypted.
A byte is all a packet says about who it is from: two nodes can share it. The name comes only with a node's advert, which a node sends now and then, so a quiet network can take a while to show its names.
## Capture