All TV antennas can be divided into two groups: active and passive, and are more expensive than the second. But they differ not only in cost but also structural features. In the active TV antenna includes a printed circuit Board, the elements of which share of the received frequency into necessary and unnecessary.
Passive receivers, as a rule, consist of vibrators – receivers. In the device using the vibrator occurs the underlying frequency distribution-that is, those elements keep the plates in the "working" frequencies and transmit them to the receiver.
On purpose TV antenna klassificeret stationary antenna of television (antenna for the city and for the house), as well as the interior. Choosing a stationary TV antenna, note that it must be installed on a four-foot distance from the roof. Higher quality signal is transmitted to the stationary antenna of television.
Choose the in-car TV antenna is not easy. Regular TV antenna works conditionally. For best signal reception the antenna should be as high as possible above the surface (it is not necessary to mount in the bumper).
When selecting antenna of television attention should be paid to the parameters of this device. One of them is the operating frequency range. Besides, important figures – the directivity factor (indicates how many times the signal of this antenna of television more reference), the ratio of the traveling wave (alignment of the antenna with the cable), the coefficient of protective action (determines the noise immunity of the antenna).
Another parameter antenna of television – directional diagram. This indicator characterizes the level of the signal issued by the antenna.