Field Guide · term

Also known as: wavelength

Wavelength (λ) is the physical distance a wave covers in one complete cycle.1 For a radio wave it is inversely proportional to frequency: higher frequency means shorter wavelength.

λ = one cycle λ (m) ≈ 300 ÷ frequency (MHz)
Wavelength is the physical length of one cycle — inversely proportional to frequency.

How it works

Since radio travels at the speed of light, λ = c / f. A handy approximation is λ (metres) ≈ 300 ÷ frequency (MHz) — so 150 MHz is about 2 m and 460 MHz about 0.65 m.

Relevance to SDR

Wavelength sets antenna size (a quarter-wave whip is λ/4) and influences how signals bend around obstacles, making it central to antenna choice and propagation.

Sources

  1. Wavelength — Wikipedia, on the spatial period of a wave and its inverse relation to frequency. ↩

See also

Learn it step by step