Frequency
MHz
Results
Antenna length (L)
ft
Dipole leg length (l)
ft
Wavelength
ft
½ wavelength
ft
¼ wavelength
ft

# Dipole Calculator

By Łucja Zaborowska

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