# Dipole Calculator

By Łucja Zaborowska, PhD candidate
Last updated: Jul 28, 2020

Our dipole calculator is a simple tool that allows you to compute the length of a simple antenna - it'll also provide you with the value of the wavelength and the adjustment factor [k].

In the text below, we will cover the basic rules of antenna construction, how to calculate dipole antenna length, and explain how to put our wire antenna calculator to work.

## How to use the dipole calculator?

In order to use our antenna calculator, you'll need to know the frequency on which you want your antenna to operate.

• Your total antenna length (L);
• Length of one arm of the antenna (l); and
• Wavelength, as well as its portions: 1/2, 1/4 (it'll also allow you to use it as a 1/2 wave dipole calculator).

You may enter the diameter of your conductor to obtain the adjustment factor [k]. You may need it for high frequencies and thick wires, or if your antenna will be made out of the tube.

 💡 The lengths used in our dipole calculator are inches, centimeters and all other popular units. Feel free to play with the numbers however you like!

Try our other essential tools:

## How is dipole antenna length calculated?

The antenna length formulas used in our dipole length calculator are as follows:

`L = 468 / f`

`l = L / 2`

Where:

• L - the length of the total dipole antenna in feet (ft);
• l - the length of the arm of the dipole antenna in feet (ft); and
• f - the desired frequency.

We also used the simple wavelength formula:

`Wavelength = c / f`

Where:

• c - the speed of light: 299,792,458 m/s; and
• f - frequency.

If you want to use the adjustment factor [k], you'll need the following version:

`L = 0.5 * k * c / f`

Where:

• c means the speed of light; and
• k is the adjustment factor, calculated with a following equation (simplified version):

`k= 0.9787 - [(11.86497 / (1 + (R/0.000449)1.7925)0.3)]`

Where:

• `R = ½ wavelength / Diameter of a conductor`.

## Dipole FM antenna length and construction

Dipole antennas are the easiest and probably the cheapest antennas to construct. They can give you a great insight into how antennas work and can be an excellent start for a beginner.

What will I need?

• Some wire - usually made out of copper;

• Insulators - should be placed on both ends of the wire;

• A dipole centerpiece (an insulator can serve this purpose);

• ... with a feeder attached to it - usually a coax cable with an impedance of 50 Ω (remember to seal the endings!);

• Fixings;

• Two high-located, obstruction-free points to plant the antenna - the dipole's length is the most crucial feature to consider; and

• Of course - our simple dipole calculator to assess the length of the device

It is recommended to cut the wire a little bit longer than calculated, and then trim it to the length that provides you with the best results.

Łucja Zaborowska, PhD candidate
Frequency
MHz
Results
Antenna length (L)
ft
Dipole leg length (l)
ft
Wavelength
ft
½ wavelength
ft
¼ wavelength
ft
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