# 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