CONSTRUCTION OF YAGI ANTENNA
ABSTRACT
An Antenna is a device to transmit and/or receive electromagnetic waves (often referred to as radio waves). Antenna also radiates energy as possible because radiation is the primary function of the transmitting antenna.
The constructed Yagi Antenna can operate with the range of UHF Channels or band.
It has a high gain factor that can be in all channels such as UHF and VHF. The Yagi Antenna has better selectivity.
Aluminum rod of 0.86m was equally bent to form the dipole of 0.43m. a 75mm coaxial cable, BNC plug, screws and support grip were used in the construction. They were separately cut to required measurement.
One wire of the Coaxial cable was joined to dipole; the others to the parasites (directors and reflectors). The spacing between the parasites and the dipole is 0.15.
The constructed antenna was tested with a television set and it received UHF and VHF transmitted by Enugu State Broadcasting Service and Nigeria Television Authority.
Due to the omni-directionality of the Yagi Antenna, it was tuned to a particular transmission area to have a better selectivity. The antenna has to bring a clear reception.
CHAPTER ONE
1.0 INTRODUCTION
An antenna is a specialized transducer that converts radio- frequency (RF) fields into alternating current (AC) or vice versa. There are two basic types: the receiving antenna, which intercept RF energy and delivers AC to electronic equipment, and the transmitting antenna, which is fed with AC from electronic equipment and generates an RF field.
A Yagi antenna, also known as Yagi-Uda array or simply a Yagi is a unidirectional antenna commonly used in communications when a frequency is above 10MHZ. this type of antenna is popular among amateur Radio and citizens Band radio operators. It is used at some surface installations in satellite communication systems.
A basic Yagi consists of two or three straight elements, each measuring approximately ½ electrical wavelengths.
The Yagi antenna or aerial is one of the most successful RF antenna designs for directive application. It is used in a wide variety of applications where an RF antenna design with gain and directivity is required. It has become particularly for television reception, but is used in very many other applications where an RF antenna design is needed that has gain.
1.1 BACKGROUND OF THE STUDY
The idea of project writing and construction at the undergraduate level of higher learning is aimed at encouraging students’ participation in research activities and at the same time prepares them to face challenges after graduation.
Antennas are commonly used in Nigeria as television receivers and may not require much technology to design and construct one. This project is borne out of the need of promoting and encouraging indigenous method of constructing antenna, which If done, can save the money that have been used to buy one in the market.
1.2 OBJECTIVE OF THE STUDY
To construct a practical Yagi antenna that can be demonstrated at homes, offices or laboratories.
1.3 STATEMENT OF PROBLEM
Complete knowledge of a course is the combination of both theory and practical. Theories are better understood and interpreted in constructed piece that represents them. Nigeria has been noted as a Nation that depends solely on imported items for her electronic needs thereby giving rise to unfavorable balance of trade in her National Income accounting. There are no good facilities or industries to encourage the fabrication and construction of standard electronic equipment that will meet the international standard. This negating factor equally affects the quality of materials used for the construction of this Yagi antenna.
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