Antenna Calculator

Calculate practical starting lengths for common amateur-radio antennas.

Select an IARU region and band. Band plans are guidance; national regulations prevail.

IARU region

Calculated dimensions

½-wave dipole

Total length

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Each dipole leg
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¼-wave vertical radiator

Radiator length

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Full-wave loop

Total wire length

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Square · per side
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Equilateral delta · per side
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Physical reference

Free-space wavelength used as a physical reference.

Wavelength (λ)
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Loop reference perimeter (λ)
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Methodology

  1. 1 · Band and reference

    Select the IARU region and band. We use the midpoint of the range as the mathematical calculation reference.

    It is not a recommended operating frequency.

  2. 2 · Starting dimensions

    We calculate practical starting dimensions for a dipole, quarter-wave radiator and loop using the reference frequency.

  3. 3 · Adjust after installation

    The calculated dimensions are a starting point. Height, surroundings, materials and nearby objects can change antenna behavior, so measure and adjust it after installation.

Data Sources

IARU · Band plans · NIST · Speed of light · ARRL · Dipoles · ARRL · Verticals · ARRL · Loops