The antenna is basically composed of wires that are shaped differently. Your antenna will receive the selected television channel’s broadcast signal by contacting that particular station. Antennas receive the signals from local stations and of course the major ones. The place you live in and the height at which the antenna is installed plays an important role in deciding how many stations your antenna will be receptive to.
The design of a TV antenna is such as to receive specific over-the-air broadcast television signals. The frequency of these signals ranges from 47 to 250 MHz in the VHF band and 470 to 960 MHz in the UHF band.
The exact frequency differs from country to country. Antennas use tropospheric bending of signal, which is transmitted from originating stations to capture the signal. It basically intercepts radio waves from respective television stations and converts them into radio frequency alternating currents. This current is then fed to the television’s tuner that extracts the main signal.
The direction of the antenna
A basic television antenna can be called “low tech.” The elements in a TV antenna are specifically cut out so that the resultant product is compatible with a given frequency that the broadcasting station transmits. The antennas function according to the direction. They need to be placed in the direction of a station in order to capture the signals flawlessly.
In earlier days, television antenna elements were aligned horizontally for horizontal polarization. Nowadays, circular polarization is more often used. This allows the antenna to catch signals in any orientation.
Important specifications
TV antennas work on the basis of a number of parameters and characteristics. The important technical terms related to the working of an antenna are listed below.
- Gain- It is the ability of an antenna to receive signals pertaining to a particular frequency. Higher the gain, better the quality of the antenna. Generally, antennas with higher gains are longer in length and comprise of more parts.
- Front to back ratio- This ratio is a comparison of the front face of your antenna to its back face. The front face is necessarily that side which faces the direction of the television station. Higher front to back ratio means the antenna has more surface area on the front face rather than the back. This allows better reception of signals from the source of the broadcast.
It is imperative to note the following in order to understand the working of an antenna better.
- The boom of the antenna should be placed in the same direction as the originating station.
- The direction of polarization of the cross pieces of the antenna should be in line with the transmission pattern of the source.
- Grains- These are glitches that might appear on your television screen due to bad reception by the antenna. It can indicate a technical flaw or a weak signal from the TV station.
- Ghosting- This causes the images on your TV screen to appear faded. If the antenna reflects the same signal multiple numbers of times, this abnormality can occur. This usually indicates that your signal is clashing with the signals of other neighboring antennas.
HDTV antenna
The stream has changed from obsolete analog signals to digital signals. Digital signals enable HD quality transmission. The HDTV providers compress their signals to ease the transmission of enormous data. Local stations uncompress the signal so that your antenna receives the best quality signal.
An HDTV antenna receives electromagnetic signals from stations. An HDTV antenna is capable of providing better signals and hence better picture quality than the conventional TV antennas. Usually, the HDTV antenna receives the signal from the station as programs which are then converted into audio and video by the tuner present on the TV.