Antenna is a device used to capture or transmit electromagnetic radio signals which are then forwarded through a conductor such as a cable to be broadcasted on electronic devices such as TV.
Antennas have an important role in an electronic device related to electromagnetic waves or radio equipment. Examples such as television, radio, cell phones, Wi-Fi, and others.
Based on the beam, the antenna is divided into two types, namely:
- Omni Directorial Antenna, which is a wide beam type antenna with a larger beam angle, but the distance can be shorter. This antenna is used to receive or transmit signals in all directions. Examples of omni-directory antennas are hotspot transmitters, dipoles, cellphone antennas, and others.
- Directorial Antenna, which is a kind of narrow beam width antenna. This means that this antenna only has a small beam angle but is more directional. Examples of directorial type antennas are satellite dish antennas, sectoral antennas, Yagi, grids, bolic pans, and others.
How the TV Antenna Works in General
The purpose of a TV antenna is to receive electromagnetic waves and then convert them into electrical signals or transmit them from electrical signals to electromagnetic waves.
Based on the working principle of antennas, antennas can be classified into transducers. This is because this tool is able to convert one form of energy into another form of energy.
The antenna is composed of elements made of metal. These elements will later be connected to the transmission line contained in a transmitter or receiver of the transmitted wave.
For example, in the workings of a UHF TV antenna, the results from camera recordings are converted into electrical signals. Then the electrical signal will be amplified and flowed through the cable to the antenna.
Electrical signals that move back and forth are able to produce electromagnetic radiation in the form of waves, then the electromagnetic waves are emitted into free space.
When you turn on the television with a certain frequency, the electromagnetic waves that have been sent will be picked up by the receiving antenna.
The wave will move back and forth which can produce an electrical signal. Well, the electrical signal is what will be forwarded to the receiver on the TV so that the TV will produce the appropriate image.
Generally, to amplify the signal, a booster is added to the path between the antenna and the TV. So that later the resulting image and sound will be clearer.
That is how TV antennas work in general. TV antennas can be divided into three types, namely loop antennas, slot antennas, and dipole antennas.
How TV Antennas Work According to Type
1. Loop Antenna
Loop antennas are designed to capture electromagnetic waves more efficiently than other types of antennas. Loop antennas are more efficient because they are mobile, which means they use less electricity, and can work on various frequencies according to their needs.
While the good or bad quality of the loop antenna itself depends on the placement and construction of the antenna itself. Although, several other things can also be another determining factor. When the loop antenna finds a location that has good signal strength, the communication and signal quality will improve.
Loop antennas generally have a design with one copper or metal loop acting as the other conductor with both ends connected to the same capacitor.
You can adjust the capacity on the loop of the antenna. While the frequency itself is adjusted in reverse. Therefore, to increase the frequency you need to increase the capacitance in the loop.
In addition, if you decrease the capacitance in the loop, the frequency will also decrease. This happens because the loop capacitor on the antenna holds the electric current and then releases it for a certain time.
In other words, the longer the charge is held by the capacitor, the more electromagnetic waves will be channeled with a lower frequency level.
2. Antenna Slot
The slot antenna is an antenna created by Alan Blumlein in 1938. The slot antenna was created to support practicality in VHF (Very High Frequency) TV broadcasting with horizontal polarization, narrow vertical radiation pattern, and omnidirectional horizontal radiation pattern.
The design of the slot antenna is shaped like a flat plate that has several holes, commonly called a sliding slot. The material for this antenna is metal.
The way the loop antenna works is that if the plate is moved, the slot will emit an electromagnetic wave which is like what a dipole antenna does. Antennas are commonly used at microwave and UHF (Ultra High Frequency) frequencies.
3. Dipole Antenna
The dipole antenna is one of the simplest types of antenna compared to other types of antennas. Also, this antenna is the most used antenna.
Dipole itself is one class of antennas with radiation patterns approaching elementary electric dipoles which have a transmitter structure that functions as a support for roaring currents. These antennas generally consist of two conductive elements similar to metal rods or wires.
The way the dipole antenna works is that when a driving current is applied to the signal transmitter to receive the output signal, it will then be forwarded to the signal receiver. Where each side of the feedline to the receiver or transmitter is directly connected to one of the conductor devices.
TV Antenna Performance Parameters
Each antenna has performance parameters as a measure of the quality of the antenna itself. The first parameter is the radiation pattern, where the parameter relates to the strength of the electromagnetic waves emitted or it could be the quality of signal reception to the antenna.
The second parameter is directivity, in measuring the directionality of an antenna, the power it has must be compared at a certain point using radiation emitters in all other directions.
All parameters of the TV antenna are related to the principle and workings of a TV antenna. Therefore, you can use this as a benchmark for choosing the type of antenna you need.