The Dipole: A Simple and Effective HF Antenna

The Dipole: A Simple and Effective HF Antenna



If you're a newcomer to radio and have recently obtained your license, you may be in need of an antenna for your transceiver. However, you don't want to spend a lot of money on one. Luckily, there is a cheap and effective option available: the dipole antenna.

What is a Dipole Antenna?

A dipole antenna is the simplest and most cost-effective HF antenna available. It consists of a half-wave length wire, with a gap in the middle where it is fed. When properly constructed, a dipole antenna can provide excellent performance.

My Experience with the Dipole

When I first became licensed many years ago, one of the first antennas I put up was an 80m dipole. I was fortunate to have a fairly large garden, so I had plenty of space to string up the wire. I used some twin flex wire, measured out the dipole length, and connected it to my homebuilt transmitter. Despite not having the best equipment or knowledge at the time, the dipole worked well and allowed me to make contacts on the 80m band.

Why Choose a Dipole?

The dipole antenna is a great choice for beginners due to its simplicity and effectiveness. It is easy to construct and doesn't require any complex matching networks. Additionally, it is a resonant antenna, meaning it efficiently radiates energy at a specific frequency, resulting in good performance.

Understanding the Dipole Antenna

A dipole antenna consists of two equal-length wire elements, each measuring half the wavelength of the desired frequency. These elements are connected to a feed point in the middle, creating a balanced antenna system. When viewed from above, the dipole radiates energy in two main directions, known as the broadside radiation pattern.

Radiation Pattern

The broadside radiation pattern of a dipole antenna is directional, with the maximum radiation occurring perpendicular to the wire elements. There is still some radiation in other directions, but it is weaker. The pattern can be affected by the height of the antenna above the ground and nearby objects, such as buildings or trees.

Adjusting the Dipole

To achieve resonance on a specific frequency, the length of the dipole antenna needs to be adjusted. The formula for calculating the length of a dipole is based on the desired frequency. It is recommended to make the antenna slightly longer than the calculated length, as it is easier to shorten it if needed. The wire used for the dipole can be any conductive material, such as copper wire or speaker wire.

Connecting the Dipole

To connect the wire elements of the dipole to the feedline, a balun is commonly used. A balun helps match the impedance of the dipole to the coaxial feedline and prevents unwanted radiation on the outer shield of the coaxial cable. It is also important to use insulators at the ends of the dipole to prevent short circuits and ensure proper performance.

Installation Considerations

When installing a dipole antenna, ideally, it should be placed between two supports, such as masts or trees. However, this may not always be possible due to space limitations. In such cases, alternative configurations, such as an inverted V shape or dropping the ends of the dipole, can be used to fit the antenna into a smaller space without sacrificing performance.

Adjusting the Dipole for Resonance

Once the dipole antenna is installed, adjustments may be necessary to achieve resonance on the desired frequency. This can be done using an antenna analyser or a VSWR meter. By measuring the VSWR at different frequencies and making adjustments to the length of the dipole, the resonant point can be fine-tuned for optimal performance.

Using an Antenna Analyzer or VSWR Meter

An antenna analyzer or VSWR Meter can provide valuable information about the resonant point of the dipole antenna. By plotting the VSWR measurements on a graph, it becomes easier to identify the resonant frequency and make the necessary adjustments. It is important to keep in mind that variations in height above the ground and nearby objects can affect the resonant frequency of the dipole.

Line Isolator

When connecting the coaxial feedline to the transceiver, it is recommended to use line isolator to prevent unwanted RF currents on the outer shield of the coax. This helps maintain accurate VSWR measurements and ensures optimal performance of the dipole antenna.


The dipole antenna is a simple and effective choice for beginners in the world of radio. With its low cost and ease of construction, it provides a great opportunity to make contacts on the HF bands. Whether installed horizontally or in alternative configurations, the dipole can offer good performance with the right adjustments. So, if you're looking for a budget-friendly and reliable antenna option, give the dipole a try!

About the Author – Peter Waters

Peter Waters has been a licensed HAM radio operator for many years and has extensive experience with various antenna types. He is passionate about helping newcomers to the hobby get started and enjoy the world of radio communications.