Yagi Antenna

A Yagi antennaAn antenna transmits and receives radio-frequency signals, allowing a two-way radio to communicate. Antenna type, frequency, height and location can all affect radio performance and coverage. is a directional radio antenna designed to transmit or receive radio signals primarily in one direction. Yagi antennas use a combination of metal elements arranged along a boom to focus the radio signal, providing increased gain and improved performance compared with many conventional omnidirectional antennas.

Yagi antennas are commonly used where radio coverageRadio Coverage is the geographical area in which a two-way radio system can provide reliable communication. Coverage depends on the radios, antennas, frequency, terrain, buildings and system infrastructure. needs to be directed towards a particular area or where a radio link needs to be established between two specific locations.

What is a Yagi antenna?

A Yagi antenna consists of several metal elements mounted along a supporting boom. These elements work together to concentrate radio energy in a preferred direction.

Unlike an omnidirectional antenna, which is designed to radiate a signal around the antenna, a Yagi antenna has a directional radiation pattern. This means it can provide greater signal strength in the direction in which it is pointed.

Why are Yagi antennas used?

Yagi antennas are useful when a radio systemA Radio System is a complete communication solution comprising two-way radios and, where required, equipment such as repeaters, antennas, base stations, mobile radios and network infrastructure. needs additional coverage or signal strength in a particular direction.

They can be used to improve communication between radio infrastructureRadio infrastructure is the equipment and supporting systems behind a professional two-way radio network, including repeaters, antennas, base stations, network connections, power systems and dispatch equipment. and a remote location, particularly where the required coverage is not evenly distributed around the antenna site.

The directional nature of a Yagi antenna can also help reduce unwanted signals arriving from other directions.

Yagi antenna vs omnidirectional antenna

An omnidirectional antenna is designed to provide coverage around the antenna, making it suitable for many general two-way radio systems.

A Yagi antenna concentrates its performance in a particular direction. This makes it more suitable for applications where coverage needs to be focused towards a specific location.

The correct antenna type depends on the design and coverage requirements of the radio system.

Yagi antennas and two-way radio

Yagi antennas can be used as part of professional two-way radio systems where a directional signal is beneficial.

For example, a radio system may use a directional antenna to establish or improve a connection between a fixed radio site and another location. The antenna must be suitable for the frequencyAn antenna transmits and receives radio-frequency signals, allowing a two-way radio to communicate. Antenna type, frequency, height and location can all affect radio performance and coverage. being used and correctly aligned to achieve the required performance.

Yagi antennas and radio repeaters

Yagi antennas can be used with some radio repeaterA Repeater receives a two-way radio transmission and retransmits it, usually from an elevated location, to extend the coverage and reliability of a radio communication system. installations where directional coverage is required.

A repeater receives a radio transmissionTransmission is the process of sending voice, data or signalling from a radio using a radio-frequency signal to another radio, repeater or communication system. and retransmits it, extending the usable coverage of a radio system. The choice of antenna is an important part of the overall system design.

A Yagi antenna may be appropriate where the repeater needs to provide focused coverage towards a particular area rather than equally in every direction.

Yagi antennas and VHF and UHF

Yagi antennas are available for different radio frequencyFrequency is the number of cycles a radio wave completes each second, measured in Hertz. In two-way radio, frequency determines where a transmission operates within the radio spectrum. ranges, including VHF (Very High Frequency)VHF (Very High Frequency) is the 30 MHz to 300 MHz radio-frequency range. VHF two-way radios are widely used for professional communications across outdoor, rural and open areas. and UHF (Ultra High Frequency)UHF (Ultra High Frequency) is the 300 MHz to 3 GHz radio-frequency range. UHF two-way radios are widely used for professional communications, particularly in buildings and urban environments..

The antenna must be designed for the frequency range being used. A Yagi intended for one frequency range should not simply be assumed to be suitable for another.

A professional radio system designer will consider frequency, gain, bandwidth, installation location and the required coverage when selecting an antenna.

Yagi antenna gain

One of the key characteristics of a Yagi antenna is its gain. Antenna gain describes how effectively the antenna concentrates radio energy in a particular direction.

Higher gain does not simply mean that a radio system will work better in every situation. Because a Yagi is directional, its increased gain is achieved by concentrating the signal rather than distributing it equally in all directions.

The required gain depends on the application and the design of the wider radio system.

Yagi antenna alignment

Because a Yagi antenna is directional, its alignment is important.

The antenna needs to be pointed towards the intended coverage area or remote radio site. Incorrect alignment can reduce the effectiveness of the antenna and may result in weaker or unreliable communications.

For installations involving long distances or difficult terrain, professional planning and alignment can be particularly important.

Yagi antennas and radio coverage

A Yagi antenna can form part of a wider radio coverage solution where terrain, buildingsAn antenna transmits and receives radio-frequency signals, allowing a two-way radio to communicate. Antenna type, frequency, height and location can all affect radio performance and coverage., distance or other environmental factors affect communication.

However, changing the antenna alone does not necessarily solve a coverage problem. Radio frequency, antenna height, cable losses, repeater location, terrain and surrounding structures can all influence the final result.

A site surveyA Site Survey is an assessment of a location to determine whether a two-way radio system will provide the required coverage, reliability and performance. can help determine the most appropriate approach where reliable coverage is critical.

Yagi antennas for point-to-point radio links

One common application for directional antennas is a point-to-point radio link.

In this type of installation, antennas at two locations are directed towards each other to establish a communications path. This can be useful where radio infrastructure needs to connect separate buildings, sites or areas.

The feasibility of a point-to-point link depends on factors such as distance, frequency, antenna height, line of sight and the surrounding environment.

Yagi antennas and DCS 2 Way Radio

At DCS 2 Way Radio, antenna selection forms part of designing reliable two-way radio communication systems.

Where a directional antenna such as a Yagi is appropriate, the requirements of the site and the wider radio system need to be considered before installation. This can include the radio frequency, required coverage, antenna position, height and direction.

For organisations requiring dependable communications across larger or challenging sites, professional radio system design can help identify the appropriate combination of radios, antennas, repeaters and other infrastructure.

Related radio terms

• Antenna
• Radio Frequency (RF)Radio Frequency (RF) refers to electromagnetic waves used to transmit voice and data wirelessly. Two-way radios use RF signals to communicate between radios, repeaters and other system infrastructure.
• Repeater
• VHF (Very High Frequency)
• UHF (Ultra High Frequency)
• Site Survey
• Radio System
• Coverage
• Wide Area Network (WAN)A Wide Area Network (WAN) connects networks across large geographical areas. In professional radio systems, WAN connectivity can link repeaters, radio sites and control rooms to provide wider-area communications.