Amplification coefficient
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.
UHF frequency range
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.
Amplifier
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.
