How to Design a Yagi

By Teresa Rodriguez

Man carrying a basic Yagi antenna showing all elements.
i Phil Goodwin/Getty Images News/Getty Images

A Yagi antenna is an old and proven antenna design for radio frequencies. Originally developed in 1926 by Shintaro Uda and Hidetsugu Yagi, the antenna was first used in World War II for radar communications. The ubiquitous nature of radio waves, however, means that a Yagi antenna can be built for Wi-Fi, radio and TV reception and any other programming that is transmitted over radio waves. Just include the three basic elements: the reflector, the driven element and the director in a multiple of the radio band that you wish to capture.

Construct the boom. The boom can be metal, wood or PVC pipe. The elements bisect the boom, creating the dipole arrangement that is indicative of the Yagi design.

Measure and cut the elements. The elements are multiples of a specific frequency or frequency range sought to be captured. For example, Wi-Fi is 2,400 MHz, CB radio is 2,700 MHz and 3G cellular communications are 3,000 MHz.

Attach the elements to the boom. Each element should be a quarter wavelength from the preceding element.

Attach a cable, USB or other connector to the antenna elements to carry the signal to the receiver.

Connect the connecting cable between the Yagi antenna and the receiving source, and position the antenna for the strongest signal reception.