TV Antennas: specifications, types

Types of broadcasting for which the antenna is designed. Different types of broadcasting differ in the frequencies used and signal characteristics, which requires appropriate features in the antennas.

— Analogue TV. Classic terrestrial broadcasting in analogue format. Due to the low quality of the signal and the tendency to interference, today it is considered completely obsolete, it is found mainly in those regions where DVB-T/T2 (see below) digital broadcasting has not yet been deployed. However, the requirements for antennas for analogue television broadcasting are no different from those for "digital" ones; therefore, almost all modern models, even those originally created for DVB-T/T2, work with an analogue signal without any problems.

— DVB-T/T2. Digital terrestrial television, which replaced the analogue described above. Its main advantages are the ability to work with HD formats, as well as the fact that the quality does not depend on the signal level: either the viewer receives a full-fledged "picture" and sound, or they disappear completely (with a critical decrease in the signal level). Technically, DVB-T and DVB-T2 are different standards that are not compatible with each other; however, they have the same antenna requirements, so in this case, both types of broadcasting can be described together.

— FM radio. The FM range (more...precisely, the standard) is very popular among music radio stations due to the high quality of the transmitted sound, including stereo capabilities. FM broadcasting is carried out in the range of 87.5 – 108 MHz, which is not used in television broadcasting; therefore, for devices with FM tuners (TVs can also be equipped with such receivers), you should choose antennas in which compatibility with this range is directly stated.

Implied way to install the antenna.

— Street. Models designed for outdoor use. Such an installation does not impose special restrictions on size and design, which allows to focus on technical specifications. Thanks to this, outdoor models are generally more advanced than indoor models, a properly installed external antenna allows you to achieve reliable reception even in places with a rather weak signal. Another difference from indoor models is the improved protection from dust, water and other adverse factors. Most outdoor antennas are equipped with mounts for permanent installation on a horizontal or vertical surface (such as a roof or wall).

— Room. Antennas designed for indoor installation. Usually, they have a relatively compact size, a rather elegant design compared to their outdoor counterparts, and they are also easier to install — you just need to install the device on any suitable surface. At the same time, the specifications of such models are noticeably inferior to other types, they are suitable only for places with a high TV signal level (for example, upper floors in low-rise buildings and a small distance from the repeater). And even in such cases, in order to achieve reliable reception, it may take a long and troublesome search for the optimal location for the antenna.

The amount of received signal amplification provided by the antenna. The higher this indicator, the more confidently the antenna will work in conditions of poor reception, the lower the signal level at which it will be ineffective. At the same time, it is worth considering that a high amplification coefficient is not a guarantee of high quality. Firstly, unscrupulous manufacturers and sellers may indicate figures in the specifications that do not correspond to real indicators. Secondly, the antenna amplifies not only the useful signal, but also various interferences, and in some cases a low amplification coefficient is preferable (for example, in dense multi-storey buildings, when the signal reaches the antenna from different directions and with different delays). And thirdly, performance above 40 dB can only be achieved using amplifiers (see below) — and amplifiers are also a source of noise, which in some situations can be quite noticeable.

The frequencies in the VHF range for which the antenna is designed. VHF includes frequencies from 30 to 300 MHz antennas with full coverage of this range are quite rare, but this is not required, because TV broadcast frequencies occupy only a part of VHF, and this part usually overlaps quite well.

Antenna sellers generally choose to sell models that are compatible with local frequencies. Therefore, in general, the frequency range is a rather specific parameter that the average user rarely needs — except when buying an antenna in another country. Also note that FM broadcasting in Europe and America uses the 87.5 – 108 MHz range, and antennas for such broadcasting (see "Signal Reception"), by definition, must cover these frequencies.

The frequencies of the UHF range for which the antenna is designed. UHF includes frequencies from 300 MHz to 3 GHz, however, frequencies above 900 MHz are practically not used in terrestrial television broadcasting, so TV antennas cover only the lower part of UHF. Also note that some manufacturers indicate a general range for their models, without dividing it into VHF (see above) and UHF; in such cases, this range is also indicated in this section.

Antenna sellers generally choose to sell models that are compatible with local frequencies. Therefore, in general, the frequency range is a rather specific parameter that the average user rarely needs — except when buying an antenna in another country.

The internal resistance of the antenna to alternating current. The standard value for modern TV antennas is 75 ohms; it is this impedance that the connecting cable used to connect the antenna to the receiver should have — otherwise there can be no question of normal use.

The presence of an active signal amplifier in the design of the antenna.

Any antenna amplifies the received signal due to its shape only, however, in some models, the design is supplemented by a separate electronic unit that increases the signal level at the output — an active amplifier. Antennas with this feature have the advantage of high amplification coefficient, which can also be achieved at a much smaller size than in models without amplifier. On the other hand, the amplifier requires an external power supply and is a potential source of interference since its circuits inevitably create their own noises. Therefore, in fact, the use of such antennas is justified only in areas with a weak signal level and the absence of interference and reflections — for example, in rural areas at a great distance from the repeater. In conditions of confident signal reception, the amplifier can turn out to be not only useless, but even harmful.

The ability to control the built-in amplifier allows to stabilize the wave impedance between the antenna cable and the receiver. This prevents overloading, which in turn affects signal quality. Often, television antennas with a gain control option are equipped with their own 12 V power supply.

The capability to change the tilt angle of the antenna relative to the stand or mount (for indoor and outdoor, respectively, see "Installation type"). This feature can greatly facilitate the selection of the optimal position, especially if the antenna has a narrow directivity or is used in urban areas with an abundance of reflected signals.

The length of the connecting cable supplied with the antenna (often non-detachable). Quite a lot of models come with a cable right away, which eliminates the need to purchase it separately. And knowing the length of the cable, you can evaluate whether it is enough to reach the TV without additional cables.