Skip to content
Open calculators

Quarter-Wave Antenna Length

Estimate a quarter-wavelength radiator length with an explicit user-supplied velocity factor.

Inputs

Inputs

Range: 1–300,000 MHz

Enter intended resonant frequency in MHz; the result is a free-space electrical quarter wavelength adjusted by velocity factor.

Range: 0.1–1

Enter actual conductor/insulation velocity factor. Use 1.0 only for a free-space reference; this is not a universal shortening factor.

Result

Quarter-wave electrical length (ft)
1.599987
Quarter-wave electrical length (m)
0.487676

Formula

Calculation logic

Formula definitions and substituted values.

Related calculators

Screening tool. Verify the result against the manufacturer's published rating, the actual equipment, route, floor, and applicable local requirements before ordering, installing, or relying on it.