Electron

Sources of Noise Cosmic (Big Bang, Galaxy, Sun, Planets) Atmospheric (Lightning - 40 per second) Man-made (Electrical, EMI) Ground (Nuclear Decay) Thermal (Electron Movement) Junction (Transistor)

Sources of Noise

Cosmic Radio Noise (1932) Galactic radio noise is random noise that originates outside the Earth's atmosphere. It is experienced at frequencies above 15 MHz when highly directional antennas are pointed toward the sun or to certain other regions of the sky. Sources are: Sun, Planets and center of Galaxy. In 1932, Karl Jansky, a physicist working for Bell Telephone Labs, build a rotating 20.5 Mhz yagi and discovered a source of noise was from the center of the Milky Way.

Karl Guther Jansky 20.5 Mhz (1932)

Atmospheric Noise The sum of all lightning worldwide flashes (40 per second) results in atmospheric radio noise. It is the combination of white noise (coming from distant thunderstorms) and impulse noise (coming from a near thunderstorm). The power-sum varies with seasons and nearness of thunderstorm centers. Although lightning has a broad-spectrum emission, its noise power increases with decreasing frequency.

Man-made Noise

Light Dimmer Noise

Electrical Noise External Internal

Street Light

Vertical vs Horizontal Antennas Noise Vertical vs Horizontal Myth or True? If true then why.

Radioactive Decay

Junction Noise

Mosfet

Thermal Noise

Noise Detector

Internal vs External Noise Internal noise is -52 dbm External noise is -30 dbm Ratio is 158 times.

Noise Cancelling Signal Enhancer