Coil-Shortened Dipole Antenna Calculator

Build an effective dipole antenna that needs much less space by adding two loading coils. This online calculator tells you how.

Coil-Shortened Dipole Diagram

Total length of antenna in feet
Open the dipole length calculator in a separate page.


Distance from center of antenna to the center of the coil in feet (Must be less than half the total antenna length given above)

Diameter of the conductor in inches (14 gauge is .065", 12 gauge is .08")
Open the wire gauge and diameter calculator in a separate page.


Operating frequency in megahertz




Use the Coil Inductance Calculator to design your loading coil. (Calculator opens in a separate page.)
To calculate the length of a full-size dipole, use the Dipole Antenna Length Calculator.


"The complete set of equations is expressed in the mathematical relationship below as Eq. 1, presented here primariliy for mathematics buffs or those having access to electronic computers." -- Jerry Hall, K1PLP, QST, September 1974

Equation for calculating the inductance of coils for a shortened dipole antenna
Eq. 1 (This is the equation that is used to make the calculation on this page.)
LuH = inductance required for resonance
ln = natural log
f = frequency, megahertz
A = verall antenna length, feet
B = distance from center to each loading coil
D = diameter of radiator, inches