Scanner, bookmarks and scenes in RTL-SDR mode
The scanner, bookmarks and stations share the side panel. Bookmarks are the frequencies you keep; the scanner watches many of them, or a whole range, for activity.
How the scanner works
Because the stick captures megahertz at a time, the scanner does not step from channel to channel. It measures every channel inside the capture in one go, many times a second. Only when your channels do not fit in one capture does it hop between captures, and while it hops the spectrum pauses and the VFOs fall silent. Keep the range within the sample rate where you can, and scanning is both faster and quieter.
The scan uses the active VFO: when a channel opens, that VFO moves there and you hear it. When you stop, it goes back to where it was.
Setting up a scan
- Scan: a Range (from, to and a step; the default is 144.700 to 146.000 MHz in 12.5 kHz steps), your Bookmarks (all, or one group), or a List you type, one frequency per line, such as
145.5M,7074kor162.4/12.5k. - Threshold: the VFO’s own squelch, Auto (10 dB above the noise) or a level you set in dBFS.
- Dwell and Resume after: how long it listens before deciding, and how long a channel must be silent before the scan moves on.
- On signal: Stop and listen, Stop until I skip, or Log and keep scanning.
While the scan holds a channel you can Skip it or Lock out one that is always busy (a carrier, a local noise source), and the scan passes it by from then on; lockouts are kept with your settings. The Activity view lists what opened and when, and the hits can be exported as CSV. A scan keeps running while you read a guide page.
Bookmarks
Add a bookmark with the bookmark button in the VFO bar, the B key, or + in the Bookmarks tab. Besides the frequency, a bookmark can keep the mode, bandwidth and squelch, a group, tags, a colour and notes. Show on the spectrum labels it where it sits, and Include in bookmark scans puts it in the scanner’s bookmark list. In Signals in view (Output bar), B saves the selected signal as a bookmark.
Bookmarks are stored in this browser only. Use Import, export to back them up as JSON.
Scenes: a whole setup in one click
A scene is a bookmark that saves the whole receiver: the capture centre, sample rate and decimation, plus every VFO with its frequency and mode. Make one for a set of airband frequencies, or for listening to several repeaters at once, and Apply brings it all back. Scenes are never scanned or drawn on the spectrum. You can keep up to 100.
Importing from other programs
The import dialog reads the app’s own JSON, CSV, SDR# frequencies.xml, the SDR++ frequency manager file and GQRX bookmarks.csv. Before you import, it shows how many bookmarks and groups the file holds and how many you already have. For duplicates (same frequency and name) choose Merge, Replace mine or Skip; replacing overwrites only what the file actually states, so a CSV without notes keeps your notes. Nothing is uploaded.