The Ultimate Guide to the Yagi Antenna: Great Tips Anybody can use

Yagi Antennas fron Novotech

Have you ever wondered how two-way radios and cellular towers can transmit signals over vast distances? The answer to this mystery lies in an engineering marvel known as the Yagi antenna or Yagi-Uda antenna. It has been used for years to extend the range of radio frequencies. It is useful in various applications, such as television reception, WiFi connections, amateur radio communication, and cellular connectivity.

This article will explain everything from how a Yagi antenna works and its benefits to the various types and designs. Additionally, we will explain how to install and test a Yagi antenna for the optimization of your setup. 

Whether you want better reception for your television or radio receiver or are looking for improved signal coverage in your area, understanding the operations of the Yagi antenna will give you greater insight into how to fulfill your goal.

What Are Yagi Antennas?

A Yagi antenna is a directional antenna with dipole and several parasitic elements. It's made from aluminum or other metal alloys. It looks like a long transmission line with a series of antenna elements connected along its length — the most prominent being the driven element and reflector. These elements are responsible for the antenna’s directional properties, meaning it can focus signal strength in one direction while rejecting signals from other directions.

The directors and the driven element work together to create a waveguide in which radio waves are amplified and re-radiated into the desired direction. It's possible to tune the Yagi-Uda antenna to a specific frequency band. It's most efficient when used in line-of-sight scenarios. 

What Is a Yagi Antenna Used For?

A Yagi antenna is most commonly used to increase signal reception strength in areas with a weak signal or if there are obstructions. It can also increase the directive gain values of the antenna, enabling it to reach farther or receive signals from distant sources. Its gain allows lower strength. It is especially beneficial for fringe reception in areas far from broadcast towers.

This antenna is great for boosting a WiFi signal, allowing you to connect better even in regions with weak coverage. It is useful in receiving signals from dual-band HAM radios, two-way communication systems, and television broadcasts. 

How Does a Yagi Antenna Work?

Yagi antennas use antenna arrays to amplify and direct electrical signals from a transmitting source to a receiving device. This is made possible by increasing the antenna's radiation resistance, making it more efficient than other antennas. It works by having a radiating element that serves as the antenna's main radiation source and parasitic elements that act as reflectors and directors. The position of the reflector is behind the main element and reflects the signal back to the driven element. The Yagi antenna propagation pattern is from the driven element to the directors. It has an end-fire radiation pattern, with the antenna axis parallel to the main lobe. 

Elements of Yagi Antennas

These Yagi antenna features affect performance:

  • Antenna length
  • Antenna element diameter
  • Antenna spacing

You achieve these measurements through a Yagi antenna calculator, for optimal performance. The basic designs of this antenna have the following array of elements.

Driven Element

The driven element or dipole is the main component of the antenna. It is the active antenna system that radiates or receives radio waves. It has a feed point at the center for attachment of the coax cable from the transmitter to transfer energy to the antenna. For it to be resonant, driven element lengths are about half wavelength. The driven element has a larger diameter than the other elements. This enables it to absorb more energy levels for increased bandwidth. It also helps ensure that the antenna can receive signals from a wide range of frequencies.

Reflector Element

This is the longest element found at the rear of the dipole. Yagi antenna reflector length is 5% longer than the driven element. The spacing between the reflector and the dipole is approximately 1/10λ to 1/4λ. This spacing depends on the side lobe and yagi antenna gain pattern specifications, bandwidth, and F/B ratio. The reflector's role is to add gain by reflecting the energy produced at the driven element and sending it in a single direction. This greatly increases the power of the signal transmitted and thus increases the range of the antenna. The reflector element also helps improve unwanted side lobe suppression.

Director Element

This element sits in front of the driven element in a direction with high sensitivity. It is the shortest parasitic element, being about 5% shorter than the dipole. It has a smaller diameter than the other elements. This helps ensure the antenna is resonant on a particular frequency or range. The director helps achieve the desired directional pattern and gain. The number of directors doesn't determine the gain of the antenna, but the length of antenna arrays does.

How To Install and Test a Yagi Antenna

  1. Assemble the antenna by fastening the reflector, directors, and dipole onto the boom.
  2. Connect the coax cable to the driven element. You may need antenna connectors.
  3. Mount the antenna horizontally with vertical elements.
  4. Tune the antenna by adjusting the lengths of each element until you achieve the desired level of sensitivity.
  5. Connect the coax cable to the transmitter. You have a usable antenna!

Testing a Yagi antenna requires positioning it in an open space with little obstruction and away from interference. You then need to measure the signal strength of the transmitted and received signals. This is done using a signal meter, in which you observe the strength of the signal from the antenna in decibels. This enables you to determine if the antenna is operating at its maximum potential.

Where To Buy Yagi Antennas 

Yagi antennas can be purchased from local electronics stores, websites, and online antenna manufacturers. Research the various distributors through Yagi antenna reviews to determine which one best suits you. Proper installation and testing will ensure you get the most out of your Yagi antenna.

Novotech is the leading provider of antennas, modules, cellular routers, and signal boosters. With our wide range of products and years of experience in the industry, we should be your go-to for all your antenna needs. Shop now and get the best Yagi antenna.