SpectraSentry / RF Spectrum & Waterfall

RF Spectrum & Waterfall

An AirSpy/SDR#-style stacked view — a live 2D spectrum directly above a frequency-aligned waterfall — the default landing display for real RF analysis.

Combined 2D spectrum over the waterfall with device panel
Combined 2D spectrum over the waterfall with device panel
What it is

The RF Spectrum tab shows a 2D amplitude trace stacked over a scrolling waterfall spectrogram that shares the same frequency axis, so a signal lines up vertically between the two. Sweep data comes from a connected analyzer (TinySA4, RF Explorer) or the RTL-SDR. The 2D trace supports live, max-hold, average and reference traces with peak callouts; the waterfall renders at up to 60 fps. Standalone 3D-surface and live-trace displays share the same data, and any tab can be popped out to its own window for multi-monitor work.

What it's for

Surveying the RF environment of a site (what is transmitting, and where in the band).

Watching a specific frequency or span for new or anomalous signals over time.

Lining up a signal’s instantaneous shape (2D) with its history (waterfall).

Documenting findings — export the trace to SVG for reports.

How to use it
  1. Connect a sweep device. Plug in a TinySA4, RF Explorer, or Nooelec RTL-SDR. It appears in the device panel.
  2. Start Skanning. Press the Start button (or F5). The 2D trace and waterfall populate with live RF.
  3. Pick a color map. Open the waterfall gear to switch maps (airspy, intensity/radar, inferno, viridis, ghost-green, grayscale) and set history depth.
  4. Zoom in on weak signals. Scroll the wheel or drag-select over the waterfall; the spectrum stays frequency-locked. Use +/−/Fit to magnify telemetry compressed across the span.
  5. Pop out. Right-click the tab → Pop Out to Window for a dedicated/secondary-monitor view.
Details
Color mapsairspy (default) · intensity/radar · inferno · viridis · ghost-green · grayscale
TracesLive, max-hold, average, reference · peak callouts · noise-floor line
WaterfallUp to 60 fps · configurable history depth · left/right stream direction
DevicesTinySA4 (100 kHz–960 MHz) · RF Explorer (15 MHz–2.7 GHz) · RTL-SDR (52–2200 MHz)
ExportSVG vector export · detachable pop-out windows · HiDPI
Screenshots
Filled 2D spectrum with peak frequency callouts
Filled 2D spectrum with peak frequency callouts
Tab context menu — pop out / full screen
Tab context menu — pop out / full screen
Detached spectrum window for multi-monitor work
Detached spectrum window for multi-monitor work
← All features Download for macOS (.pkg)