How to build antenna

       January 1, 0000    1372

 

Antenna is an electronic device. It is an arrangement of aerial electronic conductors. These are designed to transmit or receive radio waves or electromagnetic waves. Heinrich Hertz discovered an antenna in 1886. Basically the antennas convert radio frequency electric current into an electromagnetic wave. Antennas have a wide range of usage. They are used in radio and television broadcasting, communication, radar, and space exploration. The antennas mainly work in air or outer space. The modern technology has made them to work under water, through soil, and rock at certain frequencies for short distances. The antennas generate a radiating electromagnetic field in response to an applied alternating voltage and the associated alternating electric current. The electromagnetic field induces an alternating current in the antenna. It also induces a voltage between the terminals. The antennas were first used to prove the existence of electromagnetic waves.

How to make a folded antenna:

An antenna is made from 300-ohm twin lead, a brown or black ribbon like TV line. There should be two conductors running along the edges of the ribbon. The frequency of the ribbon should be known before constructing an antenna. A certain frequencies for few of the channels should be set first. Each end of the antenna should be able to twist the conductors together and solder. It is nothing but a folded dipole antenna. Now this should be connected to a long section of twin lead to bring the signal to the TV. The long piece that leads to the TV is nothing but the transmission line. One of the conductors of the antenna at the midpoint should be cut, and a half-inch should be stripped off. From the conductors of the long piece of twin lead should have strip insulation.
Transmission line to the wire should be attached at the midpoint of the conductor. Also the opposite end of the transmission line should be attached to the 300-ohm input of the TV.

Uses of antennas:

Antennas have wide range of usage in the modern days. It is used in all the fields. Each and every electronic device has its antenna. The devices like TV, radio, cell phone, and other devices use antennas. These antennas are used in radar systems, telecommunications and marine systems also.
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