Shape synthetic RF noise with per-channel controls¶
Shape the simulated RF environment when using the built-in Demo radio by enabling or disabling individual noise sources and adjusting their levels.
Before you start¶
- Connect to the built-in Demo radio from the Settings > Connect to Radio... dialog or the Connect panel
Steps¶
- Open the Demo Mode applet from the Applet Panel tray (the DEMO tray button appears only when the Demo radio is connected).
- In the applet, find the Noise channel toggles section. Each checkbox controls a separate noise source: pink noise, white noise, QRM bursts, birdies, and others.
- Check a checkbox to enable that noise source; uncheck it to disable.
- For each enabled noise source, adjust its Noise level slider to set the intensity.
- Optionally, click a Scene presets button to set all channels at once for a specific scenario (storm, night-40m, contest pileup, quiet band, etc.).
What each control does¶
| Control | Action |
|---|---|
| Noise channel toggles (checkboxes) | Enable or disable individual noise sources. Sources available: pink noise, white noise, QRM bursts, birdies, and others. |
| Noise level sliders | Adjust the level of each enabled noise source independently. |
| Scene presets (buttons) | Apply a pre-configured combination of noise channels and levels to simulate a specific band condition. |
Noise source reference¶
Hover over any noise channel toggle or level slider to see a one-line description of what that sound is and what causes it on a real HF rig. Sources include:
| Source | What it simulates |
|---|---|
| CW tone | A Morse code signal — a wanted signal that filters and notch should spare |
| Voice (speech) | An SSB voice signal — the wanted audio that noise reduction must preserve |
| White / AWGN | Flat thermal noise from the receiver itself — the baseline hiss that sets sensitivity |
| Pink / hiss | Atmospheric band noise, strongest on the low bands |
| QRN crackle | Lightning static from distant thunderstorms; noise blankers help |
| Power-line | Mains buzz (50/60 Hz plus harmonics) from power lines or arcing insulators |
| Static crash | Loud crashes from a nearby storm front |
| Birdie carrier | A steady unwanted carrier (heterodyne) — the classic notch-filter target |
| SMPS hash | Broadband hash from switch-mode power supplies (phone chargers, LED lamps, solar inverters) |
| Woodpecker | A pulsed rasp from over-the-horizon radar |
Tips¶
- Start with all noise sources disabled (all checkboxes unchecked) to hear the cleanest simulation, then enable sources one at a time to understand their character.
- Use scene presets as a quick starting point, then fine-tune individual sliders.
- The noise source tooltips double as an HF primer: they explain the cause of each sound on a real band and what to do about it.