When considering the choice of a television antenna, pay close attention to the correct formulation of the problem. The seeming triviality of the search hides the true complexity of the selection process. Satellite reception is a hyperbolic antenna, which puts the provider of television or a special master. The article does not apply to satellites.
TV reception
With towers much more confusion. It is difficult to understand where the favorite channel's repeater is located, the broadcasting is conducted from different directions, at different distances. Experts say: Moscow Ostankino tower has a zone of confident coverage of a radius of at least 50 km. Room antenna is enough for any needs of the evening show lover, exciting movies, ardent admirers of Andrei Malakhov.
Skyscrapers, high-rise buildings block direct visibility to the tower, the signal is reflected, the electromagnetic wave is attenuated, and a multipath effect occurs.
In the light of these facts, a careful choice of antenna for the TV is required.
Frequencies of broadcasting
Go to the store before expanding the outlook. For general information useful information about the bands broadcast:
- HF: 3 - 30 MHz;
- VHF:
- MW( VHF): 30 - 300 MHz;
- UHF( UHF): 300 MHz - 3 GHz.
Each state promotes its own standards, it is necessary to penetrate into the fan of soap operas and in foreign designations.(given in brackets above).
Most commercial channels have occupied the range of 100 - 900 MHz, the list shows which band the channel belongs to.
There are three known broadcast standards. There is no sense for the average viewer to go into detail in every document, but know that the frequency increases with the channel number. When buying, focus on the recording in the instructions on the capabilities of the device. Often the information is duplicated on the packaging box. Selection of a television antenna is carried out according to the need of receiving frequencies. Today's provider avoids the NE and DV, going to European standards.
Obvious ways to solve the problem. Classification of antennas
The presence of a single tower, located at a distance of several kilometers at a distance of direct visibility, will allow to maintain a steady reception room antenna. We offer to read a brief excursion into the world of reception of electromagnetic waves, presented below.
Distinguish between the indicated types of television reception devices( excluding satellite dishes):
- by location:
- are indoor;
- outdoor( street);
- hybrid.
- depending on the possibility of signal amplification:
- active;
- passive.
- range:
- broadband;
- narrowband.
Global is the division by location, the remaining signs are secondary and are present in various combinations. This covers all variety.
Indoor antennas
Active and passive
Selecting an antenna with a signal gain will greatly increase the probability of reception. The cost of room execution varies around $ 30( HAMA H-44269), complaints about the quality of the image transmitted by the said tower will not arise. The difference of the active modification is manifested by the presence of a power adapter, cumbersome design, additional service options.
For $ 6( Ramo Volga MV) buy a passive indoor antenna( without amplifying the signal).It differs from a simple piece of wire with two key features:
- The possibility of flexible adjustment of the telescopic antennae to the wavelength.
- Guaranteed impedance matching with cable.
If the terms mentioned above cut a rumor, they are not familiar - you should not try to make an antenna yourself. It will be necessary to maintain the geometrical dimensions of the product, to carry out adjustment, using the help of special devices.
Radio lovers will be pleased with the fact that choosing the right antenna will help catch the FM band.$ 14( Bandridge VTV200) is a passive model, confidently exciting popular radio stations.
Broadband antennas
The term broadband means: all, or at least most, broadcasting stations can be received. This type of antenna is chosen if it is not known in advance which frequency is required to catch. We will recommend this type of and thrifty owners - in case of the emergence of new channels in the vicinity.
How to distinguish a broadband product? First, ask the seller, and secondly, in the instructions or on the box is written something like CF / UHF / VHF.This lists the broadcast bands. Thirdly, in addition to the telescopic whiskers, such an antenna reveals a similarity of the frame - that is, in fact, two types of antenna devices in one package. This is due to the inability to cover the entire width of the broadcast individually telescopic or frame varieties.
For $ 50, buy an excellent active( with signal amplification) broadband antenna with an additional option like a clock, alarm clock, remote control.
Narrowband antennas
When the channel frequency is known, give preference to narrowband modifications. When choosing a indoor TV antenna, inquire about local broadcasting. After learning the frequency, choose a product that supports the specified range. The channel matching list is listed above.
A narrow-band antenna is easy to learn from a relatively simple design - a simple frame or telescopic rods.
Outdoor antennas
An outdoor antenna is purchased when the receiving point is not visible from the window and the indoor antenna does not catch the signal. In this case, you must attach the device to the roof and hold down the cable to connect the TV.
The difference of external antennas in the design - telescopic options are suitable only for the room where a person has the right to adjust the antennae. The product is installed on the roof once and for all, therefore the principle of operation is different.
The robust housing hides the electronics, the metal parts are protected from corrosion, the dimensions are significant, a special mount helps installers to install the product as efficiently as possible.
More often other things are used on the street variety "wave channel."This pin is studded with a series of horizontal rods. Directed such a design in the direction of the broadcasting station. It looks like log-periodic antennas.
Not necessarily the cost of the product will be high. The hybrid model for rooms and streets is estimated at around $ 30( GAL DA-600).A slightly more expensive active broadband outdoor antenna Rolsen RDA-410, made of metal.
With such an abundance of options, it is worth thinking twice. The hybrid version may be somewhat inferior in appearance, but if you need to remove the product from the roof, installation on the balcony should not cause any hassle. A typical "wave channel" in the room does not work in the absence of direct visibility to the tower.
The external design, therefore, differs from the indoor structure and the design of the receiving elements.
Specifications and Recommendations
Gain
An important parameter is the antenna gain. Under the parameter sometimes means different things. But in the instructions and advertising brochures only active models own the gain. The signal is received, amplified and then enters the TV.
As for passive modifications, they only increase in the azimuth direction due to the design features.
Directionality of
Most products are characterized by an uneven radiation pattern, that is, with individual azimuths, the reception is better. This is done to ensure the best quality with minimal resources.
The indicated factor allows to fight with multipath. The station radiates a wave that is repeatedly reflected from the walls of houses and other objects. A number of reflected rays come to the receiving point. Despite the high speed of propagation of electromagnetic waves in space, the phase is unequal. The television image is doubled, tripled. ..
The pronounced direction of reception allows you to select a single beam - streams coming from other azimuths are ignored.
Internal resistance
Ignorance of the laws of physics plays a bad joke with ignorant buyers. The antenna is characterized by internal resistance, which should coincide with the analogous parameter of the connecting cable, two types are known:
- 50 Ohm( radio).
- 75 Ohm( television).
If additional wires are required besides those that are bundled, it is worth buying a variant with a characteristic impedance equal to the antenna. According to accepted agreements, 75-ohm cable TV.Find out about the internal resistance of products from the seller.
Design
Despite the apparent monotony, the designer vein antenna designers do not sleep. Look at the wide-band active model OFA SV 9385( $ 52) in order to verify the validity of wise words.
Similar to the panel, the modification will fit into any interior with an inconspicuous and austere appearance.
Remo Inter 2.0 costs $ 30, does not catch the radio, paying for the lack of forethought with original design.
