🎵 Audio Effects

Realistic HF conditions with QSB, QRM, chirp, and noise effects

🌊 Why Realistic Audio Effects?

Real-world amateur radio conditions include fading, interference, and equipment characteristics. Training with these effects prepares you for actual on-air conditions and improves your copying skills dramatically.

🎛️ Available Audio Effects

📡 Signal Strength (S-Meter)

S1-S3: Very weak signals (DX stations)
S5-S7: Moderate signals (normal conditions)
S9: Strong signals (local stations)
Purpose: Practice with varying signal strengths to improve weak signal copying skills.

🌊 QSB (Fading)

Effect: Gradual signal strength changes

Cycle: 7-second fade in/out pattern

Depth: 20% to 100% volume variation

Cause: Ionospheric propagation changes

Purpose: Simulate real HF propagation conditions where signals fade in and out.

🎵 Chirp Effect

Effect: Frequency slides at tone start

Amount: 50 Hz frequency shift

Duration: 50ms chirp period

Sound: "wee" on each dit/dah

Purpose: Practice with older transmitters that have frequency instability.

🔑 Straight Key

Effect: Human keying irregularities

Timing: ±20% element duration variation

Keying: Variable rise/fall times

Realism: Operator "fist print"

Purpose: Learn to copy imperfect hand-sent Morse code with timing variations.

📻 QRM (Interference)

Type: Competing CW station

Frequency: +75 Hz offset

Level: 30% of main signal

Pattern: Random morse at 25 WPM

Purpose: Practice copying through interference from other stations.

🔊 Background Noise

Type: Pink noise (1/f spectrum)

Levels: S3, S5, S7, S9 noise floor

Effect: Atmospheric HF noise

Realism: Band-specific characteristics

Purpose: Train your ears to pick out signals from atmospheric noise.

🎛️ How to Use Audio Effects

📋 Step-by-Step Instructions

  1. Start a training session in any training mode
  2. Open Advanced Settings panel during training
  3. Enable audio effects by checking the desired options
  4. Adjust intensity levels using the sliders
  5. Practice copying with realistic HF conditions
  6. Gradually increase difficulty as you improve
💡 Training Tips
  • Start with one effect at a time
  • Use lower settings initially
  • Combine effects as you improve
  • Practice regularly with effects enabled
  • Focus on the rhythm, not individual elements
🎯 Progressive Training
  • Beginner: Clean audio only
  • Intermediate: Add QSB fading
  • Advanced: Include background noise
  • Expert: Full QRM + all effects
  • Contest: Maximum realism

⚙️ Technical Implementation

🔬 Audio Processing

Real-time Processing:
  • Web Audio API implementation
  • Low-latency audio effects
  • Professional DSP algorithms
  • Hardware-accelerated when available
Authentic Modeling:
  • Based on real HF measurements
  • Frequency-dependent characteristics
  • Time-varying parameters
  • Amateur radio specific effects
Previous: Troubleshooting & FAQ Next: Statistics & Progress