User guide · LoRa Scanner

LoRa Scanner

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.

The LoRa Scanner's Sweep view: bars of signal strength from 863.0 to 870.0 MHz with peak marks, a waterfall under them, and a footer reading floor -100, 863.2 MHz at -89 dBm
LoRa Scanner, Sweep
The LoRa Scanner's packet list on LongFast 869.525 MHz while a Capture is recording: three packets, each with its time, RSSI, SNR and Meshtastic sender and hops
LoRa Scanner, packets

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.

KeyDoes
EnterThe details of a packet: the Meshtastic header, which is never encrypted, and a hex dump
pPicks one of the 7 Meshtastic presets allowed in EU868 (LongFast by default)
cStarts or stops a capture
TabSwitches 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.