Constantly paying subscription fees for using satellite or cable television services forces users to look for other ways to watch television. For owners of television receivers with a built-in digital tuner, the best option may be to receive digital terrestrial television. This becomes relevant due to the fact that in the very near future Russia is planning a complete rejection of broadcasting TV in analog format and switching to digital broadcasting. A great influence on the quality of watching television programs has the right choice of receiving antenna. In large communities near transmitting centers, users often prefer indoor antennas with amplifiers. You can find out how to choose it correctly in the article.
Types of television indoor antennas
The appearance of television antennas can determine its main parameters. These include:
- the range or frequency band in which the antenna operates;
- antenna gain.
Frequency and wavelength are directly related. Television broadcasts are carried out in the range of meter and decimeter waves. The geometric dimensions of the elements that make up industrial or homemade antennas are related to the wavelength of the received signal. The higher the frequency or the shorter the wavelength of the signal, the smaller the geometric dimensions of the antenna structure.
The range of meter waves of television broadcasting (1-12 channels) corresponds to wavelengths from 5 meters to 1 meter. Vibrators of this range are made in the form of "whiskers", the length of which can be changed depending on the number of the active channel.
This design corresponds to a meter wave antenna. Decimeter waves, which broadcast digital television broadcasts (25-60 channels), correspond to a wavelength of 1 meter to 10 centimeters. Antenna elements of this range are open frames, rings, elongated ellipses with a set of horizontal plates or metal rods mounted on a common traverse. The length of each of them does not exceed (10-30) cm.
The presence of only such structural elements allows us to call the antenna decimeter. An all-wave antenna is a combination of both antennas - meter and decimeter.
There are no special indoor antennas with an amplifier for digital television. Broadcasting of DVB-T2 standard transmissions in Russia is carried out in the decimeter wave range. For reception, any antenna of this range is used in conjunction with a decoding digital television tuner.
The antenna gain (without an amplifier) can be estimated by the number of elements mounted on a horizontal traverse. More horizontal elements correspond to a higher gain value. The presence on the traverse of a lattice located behind the vibrator (frame, ellipse) significantly increases the gain of the antenna of the decimeter wave range.
Application of antenna amplifier
Indoor antennas with an amplifier for a TV belong to the class of active antennas. The antenna itself does not amplify the received signal. The value of its gain shows the ability of the antenna to concentrate the energy of the received signal in the direction of the source of useful radiation, while reducing the intensity of the signals from other directions. It is directly related to the directional coefficient, which is determined by the design of the antenna. The gain value is expressed in decibels (dB) and is a relative value. A value of 1 dB corresponds to the amplification of a vertical pin vibrator that receives signals from all directions. The antenna amplifier amplifies all the signals arriving at the antenna (receiver) from any direction.
Its main purpose is to reduce the attenuation of the signal in the cable through which the received signal is transmitted to the TV.
When choosing a room antenna with an amplifier for a TV, the buyer should first of all pay attention to the design of the antenna itself. The accompanying documentation provides the values of the total coefficient (taking into account the amplifier). It is worth paying attention to the diameter of the cable connecting the antenna to the television plug connector, and its length. A larger cable diameter corresponds to a lower signal attenuation in it. The length should match the location of the indoor antenna with the amplifier to ensure the best reception of the television signal. Amplifier efficiency increases with increasing cable lengths.
Connecting a room antenna with an amplifier
Any amplifier incorporates active elements (transistors) that require a direct current power source for their operation. Structurally, the antenna can have an amplifier integrated in its housing or it can be made as a separate device. In the first case, a connector must be present on the active antenna housing for connecting a separate mains adapter.
When using a stand-alone antenna amplifier, the power is connected to it through a connector on the housing, and it is connected to the antenna with a television coaxial cable through a high-frequency connector. Another RF connector of the amplifier is used to connect it with a coaxial cable to the antenna input of the TV.
Features of using indoor antennas with an amplifier
It is advisable to use active antennas when removing a television receiver more than 5 kilometers from the transmitting center, taking into account the terrain and the presence of dense buildings along the path of propagation of radio waves. The installation location of the antenna in the room is selected empirically. With a limited length of the antenna cable, an indoor TV antenna with an amplifier can be placed near a TV located near a window aimed at the television center (repeater). Do not forget about the need for a power outlet to power the antenna amplifier. A large coefficient of its amplification does not always lead to an improvement in the quality of reception in urban conditions.
Conclusion
After reading the material presented in the article, an interested reader will be able to choose one that provides reliable reception of high-quality television programs from a large number of indoor antennas with an amplifier that trading offers. The location of the indoor antenna is determined empirically for each specific case.