Field Guide · term

Also known as: noise floor

The noise floor is the constant background level of random energy present in any receiver — thermal noise in the electronics plus environmental RF.1 It is measured in dBm and sets the bar a signal must clear.

noise floor — the level a signal must rise above frequency →
The noise floor is the ever-present background from receiver and environmental noise.

How it works

Bandwidth, receiver quality, and local interference all raise or lower the floor. A signal is only useful when it pokes above it; the margin is the SNR.

Relevance to SDR

A low-noise amplifier and a quiet install lower the effective floor, while nearby electronics (USB, chargers, LED lighting) raise it.

Sources

  1. Noise floor — Wikipedia, the background noise level in a measurement system. ↩

See also

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