Classification of Digital TV-Antennas
Hello everyone! The other day I was looking for a new antenna and I realized that there is a huge variety of such devices on the market. I have a technical background, so I had no difficulties while choosing antenna for myself. But I thought that for many others it would be quite complicated and I decided to write this post.
I am not going to talk about any particular models of antennas. The purpose of this article is to provide you with a detailed classification of antennas for those people who are not familiar with this technology: it will clarify all the questions. If you do not want to go into details or you do not have time, I recommend this post on PrizedReviews with reviews of the best outdoor antennas for HDTV.
Before buying an antenna, it is important to think over several basic criteria:
• distance from TV tower;
• power;
• presence of other buildings in the immediate vicinity;
• degree of interference;
• which direction do your windows face?;
• number of floors;
• features of the landscape.
There are several criteria of classification of antennas. All devices for digital television are divided into several categories:
• in accordance with the place of mounting;
• technical capability to amplify the signal;
• by a frequency range that this model can intercept.
Indoor antenna
The antenna is to be located in the room. The use of indoor antenna is possible provided that the TV receives a good quality signal. The house should be in the immediate vicinity of the TV tower. There are not many places like that because the signal is obstructed by buildings, power lines and so on. Indoor antenna is quite counterproductive in the country house and in the settlements located far from the city.
Two conditions necessary for high-quality functioning of an indoor type device:
• the distance to the nearest TV tower is under 20 km;
• insufficient housing density.
The statement that the indoor antenna can be installed in any room and that the signal will be equally great anywhere is not correct. It is necessary to select a certain model of antenna for each room individually.
Outdoor devices
They are considered universal and are used in any geographical location, including out of town. Installation should be handled by a specialist, since it is necessary to have certain technical knowledge. Competent installation will provide a reliable high-quality signal, regardless of the distance from TV tower and presence of any obstacles.
Technical ability to amplify the signal
Passive antennas
Features of performance characteristics and design:
• amplifies television signal due to the technical design of the device;
• works without using power line;
• there are no active elements capable of amplifying the signal such as transistors or microcircuits;
• a passive device cannot interfere with the signal;
• quite often the power of such device is not sufficient for receiving good images.
Models of the passive type are sufficient for premises located in the immediate vicinity of the TV tower, provided that there are no high-rise buildings around, and the device will be located ten meters or higher above ground.
Active antennas
Amplification of the signal takes place due to the technical design features and a built-in amplifier, which is mounted inside the device or is located separately. The device operates from the power line through a power supply unit.
They recommend installing it if the house is located far from the TV tower.
Sometimes the device creates noise and distortion in the received signal. There can be several reasons why it happens:
• digital antenna is used in the zone of a steady digital signal
• device was not selected correctly — do not choose a model with a gain ratio that is greater than necessary!;
• the product is of poor quality.
By received frequencies
Channel devices
They are used to broadcast certain channels with a certain frequency; as a rule, ordinary viewers don’t need such models.
Wide-band antennas
They are used where it is necessary to receive wavelengths in a certain frequency range. In particular, for broadcasting digitally, a device that operates in the decimeter range is sufficient.
All-wave antennas
They intercept channels in two frequency ranges.
Technical characteristics
Despite a huge number of digits specified in the product passport, only one parameter is important to an ordinary consumer — the gain ratio.
The performance characteristics are measured in decibels, where the higher the digit, the higher the antenna efficiency and the higher the device’s ability to amplify the signal. However, not in all cases the gain ratio can ensure a good picture. It is important that gain ratio of the device corresponds to the location of its installation. If the goods are of poor quality, it is highly likely that the indicated ratio in the technical description is non-existent.