Natural Noise Sources

These are inherent to the environment and cannot be eliminated but can be mitigated.

Earth Noise

  • Soil moisture and temperature variations

  • Earthquakes, volcanic eruptions

  • Thermal noise from soil and vegetation

  • Man-made in-ground structures

  • Variations in conductivity

Atmospheric Noise

  • Source: Lightning, thunderstorms, natural electrical discharges.

  • Characteristics: Bursts of static, most prominent below 30 MHz.

  • Identification: Increases during storms, varies seasonally.

  • Mitigation: Use directional antennas, signal averaging, and DSP noise blankers.

Ionospheric Noise & Effects

  • Source: Solar activity, geomagnetic storms, auroral events.

  • Characteristics: Causes signal fading, warbling, or absorption.

  • Identification: Correlates with solar indices (Kp, A indices), satellite data.

  • Mitigation: Operate on frequencies less affected (e.g., NVIS for low bands, higher frequencies during storms).

Galactic Noise

  • Source: The Sun, Jupiter, and background cosmic radiation.

  • Characteristics: Affects VHF/UHF bands, appears as steady broadband noise.

  • Identification: Stronger when pointing an antenna at certain celestial objects.

  • Mitigation: Use directional antennas to avoid pointing at strong sources.Dk:1