Read the spectrum and waterfall

The spectrum is an immediate view of signal power. The waterfall adds time, which helps you identify activity and drift.

Read signal level

Peaks above the noise floor usually indicate signals. A narrow fixed line can be a carrier, a birdie, or center-frequency interference.

Use the receiver passband overlay to see which energy enters the demodulator. Tune or change the passband when adjacent energy enters it.

Change the view

Open Settings > Spectrum to set the display FLOOR and RANGE, the waterfall ROW RATE and ROW HEIGHT, and the VIEW SPAN.

The same page sets trace SMOOTHING, peak HOLD, and the waterfall PALETTE.

Follow the background level

Select Auto beside Floor, or enable Auto floor in Settings > Spectrum. Auto follows the received background in the visible RF span. It holds during transmission or missing data.

Turn Auto off to hold the current floor. Moving Floor also returns to manual control. Range stays manual. These are display controls and do not change receiver gain.

RF and FSK save separate floor, range, Auto and palette settings. Configure the FSK waterfall from its own toolbar or settings page.

Pan and zoom

Zoom changes the visible part of the captured span. Pan moves that view without changing the SDR source.

Keep the tuned passband inside the source span. Retune the source center when you need signals outside the current capture.

Select an FFT window

The WINDOW selection changes the balance between frequency selectivity and the visibility of weak signals beside strong ones. Radio Bench uses a fixed analysis resolution, so there is no FFT size control.