Scanning the Band
Edit on GitHubUsing SEARCH mode systematically: sweep ranges, channel steps, and how to identify what you find on each frequency.
Scanning the Band
SEARCH mode turns the beacon into a receiver and shows the band’s occupants. This page is the systematic scan: what ranges to sweep and what the peaks mean.
The sweep ranges
| Goal | Range | Step |
|---|---|---|
| Find the beacon’s own band | 433.000 - 434.000 MHz | 25 kHz |
| Check PMR446 (receive only) | 446.000 - 446.200 MHz | 12.5 kHz |
| Survey the whole ISM segment | 433.050 - 434.790 MHz | 25 kHz |
The firmware’s scan engine handles these (see Firmware Scan Engine); the numbers here are the tactical choices.
Interpreting the peaks
| Peak | Likely source |
|---|---|
| Exactly at 433.920 | The most common device frequency: remotes, sensors |
| Wide, loud plateau | A nearby transmitter saturating the front end |
| A regular burst pattern | A beacon! Match the pattern to the schedule |
| Moving peak | A mobile transmitter (car remote in use) |
The identification procedure
- Note the frequency of a strong peak.
- Switch to fixed-frequency RX on it (see Mode Search).
- Listen or decode: a Morse burst is a beacon; continuous noise is a device.
- Log it (see Beacon Log Template).
The quiet-channel choice
When deploying, scan first and pick the quietest channel with adequate separation from the peaks. A channel 25 kHz from a loud device is usable; on top of it is not. The Frequency Planning Examples page has worked examples.
Related pages
- Mode Search for the mode
- Firmware Scan Engine for the engine
- Frequency Table Reference for the channels