20m Dipole Length Calculator

This tool calculates the physical dimensions of a 20 meter (m) dipole antenna.

20 m refers to the wavelength of the transmitted and/or received signal.

Using the calculator below at 20 meters,

  • the dipole length (L) is 31.2 feet
  • the length of each element of the dipole (l) is half of that at 15.6 feet


The total length (L) of the dipole antenna is calculated as:

L = 468 / f

where f is the frequency in MHz.

f is calculated from the wavelength. For 20 m the frequency is 15 MHz.

The length of each arm of the dipole

l = L/2

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