Wavelength guide

Frequency → wavelength quick reference

Convert MHz inputs into free-space and velocity-factor-adjusted lengths for antenna and feedline work.

Frequency (MHz)

Velocity factor

Full wavelength (free space) 21.1121 m

Half-wave length 10.5561 m

Quarter-wave length 5.2780 m

Eighth-wave length 2.6390 m

Velocity factor (applied) 0.950

Quarter-wave length (with VF) 5.0141 m

Half-wave length (with VF) 10.0283 m

Full wavelength (with VF) 20.0565 m

Velocity factor accounts for slower propagation inside coax or ladder line. Typical solid-PE coax ranges 0.66–0.8, while foam PE reaches 0.82–0.88.

Tip: use the electrical quarter-wave result when cutting matching stubs or phasing lines.

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