twislaandClaude Opus 5.5
34e6714785
Every screen's keys are constant tables in lib/core/src/app_keys.h (52 of them, each under an `// id: Title` comment). An App's help() picks the table of the state it is in. site/tools/gen_dev_docs.py reads the same file and writes site/data/keys.toml; the `keys` shortcode shows a screen's tables on its guide page, and /guide/keys/ shows all of them. The Site job fails when the data file is out of date or a page asks for a table that doesn't exist, and now also runs when app_keys.h changes. A key added to an App shows up on the website without anyone editing a page. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT
2.3 KiB
+++ title = "LoRa Scanner" description = "Listen to the radio: every packet it hears, a survey of signal strength from 863 to 870 MHz, and captures for Wireshark. It only listens." weight = 2 [extra] tag = "LoRa Scanner" screens = ["sniffer.png", "sweep.png"] +++
The Scanner uses the Cap LoRa-1262. It never transmits: it listens and shows.
Sniffer
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.
| Key | Does |
|---|---|
| Enter | The details of a packet: the Meshtastic header, which is never encrypted, and a hex dump |
| p | Picks one of the 7 Meshtastic presets allowed in EU868 (LongFast by default) |
| c | Starts or stops a capture |
| Tab | 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.
Capture
A capture records packets into a pcap file with LoRaTap headers in /captures/lora/ on the SD card, to open in Wireshark. It keeps recording with the App closed (the Status Bar shows CAP); the radio sleeps when the App is not open and no capture is running. Captures are never deleted unless you ask, in the Storage App, which can also show a pcap's packets on the device.
Sweep
Tab switches to the Sweep: the signal strength across 863 to 870 MHz in 100 kHz steps, drawn as bars with a mark at each peak, and a waterfall under them. The frequency the Sniffer listens on is marked. The Sniffer is paused during a Sweep and picks up where it was. The Status Bar shows SW.
The GNSS receiver raises the noise
The GNSS receiver on the same Cap makes the radio's noise floor about 8 dB worse while it runs. Settings → Pause GNSS for LoRa (off by default) puts the receiver on standby while the radio listens, except while a Track is being recorded.
The keys, as the device lists them
What Fn + h shows on these screens. These tables are generated from the firmware's own lists, so they are always the current ones.
{{ keys(scopes=["lora", "lora-packet", "lora-presets", "lora-sweep"]) }}