Device for improving TV signal. Terrestrial digital television in the country

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Instructions

Please note during installation antennas terrain characteristics. Guaranteed television reception area signal but it depends on the terrain. If possible, install the antenna on the most high point adjacent to your home. To ensure the required height antenna device if necessary, use an additional mast, securely strengthening it with guy wires.

Choose the optimal reception design antennas. The requirements for it are as follows: simplicity and reliability, sufficient spatial selectivity, the ability to pass a wide frequency band, low input impedance and high gain signal A. For an area of uncertain reception, the level ratio is also of particular importance signal and to the level of interference.

If you are at a short distance from the telecentre (several tens of kilometers), use it to improve the received signal and an antenna of the “wave channel” type with a simple or loop vibrator, consisting of three elements. Antennas of this type are produced by industry, but if you have minimal amateur radio skills, you can make it yourself.

Check for correct installation antennas and configure it. To do this, select the optimal ratio of element sizes antennas required for admission signal and the selected stations. Correctly orient the structure in space by aiming the antenna at the broadcast center or repeater.

Use for improvement signal a special antennas th amplifier. The dimensions, design and connection method of such a device can be very different. When choosing an amplifier, pay attention to the information indicated in technical documentation frequency characteristics and noise level. Setting up the amplifier used for specific model TV receiver, have it done by a professional. Otherwise, the efficiency of the device will be low.

To improve the quality of the received image and “catch” previously inaccessible channels, it is not necessary to buy a new powerful antenna. The receiving ability of the antenna depends on various external factors, from the shape and design, changing which you can adjust the image quality.

Antenna location

Quality TV signal directly depends on the location of the antenna. Concrete walls, metal fences and structures greatly interfere with the passage of the signal, so most often it is located outside the house, on a wall or. If you know where the nearest transmitting tower is, the antenna should be pointed in its direction.

Changing the antenna design

Almost any antenna can be equipped with a special television signal amplifier. It operates on a 220 V network; you can buy the amplifier at most electronics stores. For the right choice it is important to know some parameters: noise figure (it should be as low as possible, preferably no more than 2 dB), gain Ku (calculated based on the presence of branches and its length).

Most often, the antenna design is thought out taking into account standard search air signal. It can be changed using any metal object that conducts current: wire, cable, balcony dryer, central heating radiators, etc. Aluminum and copper items with a large surface area work best. Metal objects that are not in contact with the antenna, on the contrary, interrupt the signal.

Some antennas require special settings before use. You should check whether the correct frequency range is set to receive a particular signal.

Common-mode grating effect

If you take several identical antennas and space them horizontally so that the signal phases in them are the same, you can achieve significant amplification. For example, if a single antenna gives a coefficient of 7 dB, then a double antenna - up to 10 dB, consisting of four parts - up to 12 dB, etc.

Basic rules of the common-mode array: the parts can be purchased or made independently, but must be the same. It is important that the “floors” and “rows” are completely symmetrical, with the same length of lines and cable jumpers. For fixation, frames made of insulating materials, such as wood or plastic, are used.

Reception of digital TV signal (DVB-T2) in extremely harsh conditions.
Due to the greyhound nature of Tricolor, I decided to “finish off” digital terrestrial TV at my dacha.
The first (winter) attempt ended in failure: it worked in cold weather, but at zero and above there was not enough signal. Reasons: in summer the absolute humidity is much higher than in winter, lowland near the river and nearby forest. Let me remind you that my directional relief to the repeater gives a completely “closed interval”, i.e. the signal should not pass through... A relief with a refractive ellipse is attached. A
I bought a highly sensitive receiver (-82dBm) and moved the antenna from the house away from the forest (to the summer kitchen). Now it’s 100 meters to the forest, but it was probably 20 meters (an acute angle towards the repeater).
I bought and connected/stretched 23-25 meters of RG-6U cable.
I installed an antenna lightning arrester at the receiver input. We should probably install it at the output of the amplifier, but we won’t get around to it yet. And at the input, the antenna amplifier has short circuit according to direct current, so I think it is protected well.
Result, in general, positive (compared to what it was before): at 650 MHz the signal strength is 80%, and at 722 MHz - 48%. On both, “quality” is 100%, which I don’t believe. Of course, 48% is not enough, but it works. On the verge. When the receiver warms up and as the play progresses, there are signal interruptions... Moreover, the antenna had to be very precisely aligned in the direction.
I didn’t like it and decided to “finish off” further.
I installed a second amplifier in the house in front of the receiver (an ancient one, from an old antenna).
At the same time, I had to overcome the excitation of the amplifier and the too strong signal.
A strong signal won out over splitters, which is right for me, because I want to distribute DVB-T2 around the house.
Now both multiplexes have a signal level above 90%. And the quality... - see Note-3.
Liked.
Lightning protection:
I attached a meter-long thick aluminum lightning rod to the top of the antenna mast, and organized it through an aluminum-to-copper adapter With his lower part(and not from the bottom of the mast!) a copper descent to the grounding, for which I bought and hammered a galvanized pipe 1.6 meters under the antenna. A steel cable was welded to the same grounding, to which it was tied antenna cable, going from the summer kitchen to the house. Copper to steel pipe - through stainless washers.
Note-1:
It is assumed that the TV (at least) and the rest are grounded, otherwise interference may form at the receiver input (up to 100-150 Volts), which, with the antenna grounded and temporarily open antenna input may (when connected) break through the mast antenna amplifier at the output. And this is not a theory, but a cruel truth of life.
Note-2:
It’s strange that my signal quality indicator is almost always 100%. I do not believe!

Update dated July 11, 2015:
Note to those who insist that reception does not deteriorate when it rains.
The other day we had a wild downpour. So during it, the signal at 722 MHz completely disintegrated, and was added to 650...
It’s clear, because My signal-to-noise ratio is borderline. And the antenna is not the longest-range...
I scratched my turnips and tore up the ones that were lying around old antenna, made 6 directors about 14.5 cm long (this is the length of the directors of the purchased part of the antenna), screwed them to the main antenna. After this, the signal level, deliberately roughened to 50%, rose to 65% (compared to a purchased antenna). How many in decibels, of course, is unknown...
We're waiting, out of the rain!
Update dated July 21, 2015:
Result of antenna modification:
Today we had a very heavy downpour again, both of my Tricolors (I temporarily have two antennas pointing at 36E) went off for 5-10 minutes, and my CETV didn’t turn off for a second...
Here, by amplifying the antenna itself, I raised the signal-to-noise ratio and therefore the signal was no longer “on the edge” and the effect was no longer noticeable. However, the signal level during rainfall decreased from 91% to 72% (at the minimum point).

Now the antenna looks like this:

Addition to the antenna modification results:
There were heavy rains and thunderstorms. I noticed that at the moment of a distant lightning discharge the image is disrupted for 2-3 seconds...
Note-3:
I bought a slightly different receiver from the same company for a friend and was additionally convinced that the almost constant 100% signal quality on my receiver was a fiction. This new receiver"measures" more or less normally. The quality on it (from the same antenna-feeder system) is 60-70%. By the way, its software menu and controls are different.
Apparently, I will shake the manufacturer/representative to provide a software update, which is much better in terms of convenience.
Note-4:
Forum member about static electricity during snowfall from an antenna on the 27 MHz band ( copper wire vertical):
Note-5:

We decided to write an article for people who do not have the opportunity to connect to cable television. This is rarely seen now, mainly in towns or villages. In such cases, you will have to use a regular television antenna, with which you can receive TV signals and watch TV. You can buy good and powerful antenna to improve the quality of the channels you watch. We will tell you how to strengthen the signal of the television antenna that you have at home with your own hands at home.

How to strengthen the TV antenna signal?

Let's look at four simple and popular ways to boost a TV antenna signal at home:

Method No. 1

The easiest way is to use a television signal amplifier. With this device, which we connect to our antenna, we can strengthen the received signal. The device can be easily purchased at any store.

Method No. 2

Using more than one antenna. We take several antennas and take them outside your home, and you need to combine them. Two or more antennas that are combined together will work the same as installed antenna on high level(roof of a high-rise building). This will make it possible to make the signal stronger. The ideal option would be to mount the antenna on the roof, or at another high point - the higher, the better.

Method No. 3

You can expand (enlarge) your antenna using a regular television wire, which will significantly improve the quality of the received signal. Reduce or enlarge the piece of wire (that you attached using adhesive tape), change its location. After testing several options, you will see an improvement in the signal.

Method No. 4

Objects that can conduct electricity (metal, iron, etc.) significantly degrade the signal. All these elements greatly affect the quality of the signal your home antenna receives.

It's hard to imagine life modern man no TV. At the same time, some take full advantage of the advanced smart functionality of receivers, while others choose to watch programs and movies using the old proven method - using broadcast signals digital or analogue broadcasting. At the same time, the pleasure of watching programs is often spoiled by the poor quality of TV signal reception. In our article we will try to talk in as much detail as possible about the methods of strengthening them.

What determines the quality of TV broadcasting?

There are several factors that influence the quality of the transmitted image:

The television receiver is located at a great distance from the signal repeater.
The presence of external obstacles, both natural and artificial. These can be the walls of high-rise buildings, hills, lowlands and a large number of trees.
Poor quality connecting cable.
The antenna is installed in the wrong location or is poorly oriented in space.
The presence of significant metal structures in the signal path or in the immediate vicinity of a television tower.

In almost each of the listed cases, the leading role is given to the TV antenna. If this attribute is correctly selected and configured accordingly, then there is a real chance of improving the quality of received signals and stabilizing the broadcast.

The industry produces both indoor and outdoor antennas. Where they are installed is clear from their name. Let's look at each type in more detail.

Antennas for indoor use

Portable antennas are quite affordable prices can perform their functions perfectly if the place of their use is close enough to the repeater. This means a distance not exceeding thirty kilometers. And the highest effect can be achieved when the TV tower, as they say, is visible from the window. In this case, the signals will not deteriorate due to multiple reflections from the walls of buildings.

For indoor antennas, it is customary to divide them into two categories, depending on the design features:

Frame. This type of antenna has an open metal frame. Their operating range is UHF (decimeter). It includes frequencies from 300 MHz to 3 GHz, but, as a rule, frequencies above 900 MHz are not used for television broadcasting.
Rod. “Horned” as they were popularly called. With their help, television signals are reliably received in the meter range (VHF), that is, at frequencies from 30 MHz to 300 MHz.

For effective use indoor antenna it is necessary to find a place where it will work most effectively. This means that it must encounter as many obstacles as possible on the path from the broadcaster to the receiver of television signals.

If all conditions are met, but a high-quality picture cannot be achieved, then you can try using an antenna that has active amplifier. In addition, there are also autonomous signal amplifiers, which we will discuss below.

If the user lives in close proximity to the translator, then he may have to purchase a device diametrically opposed to the amplifier, which is called an attenuator. But it serves to attenuate the signal, which helps prevent picture and sound distortion that appears as a result of a too strong TV signal.

Outdoor antennas

Half-wave vibrators.
Wave channels.
Log-periodic antennas.
Common-mode antenna arrays.

In order to cover the meter and decimeter ranges, it is recommended to use a combined solution, in which one design contains elements of several of the above types of antennas.

The quality of the received TV signal is directly dependent on the height at which the antenna is installed. A significant impact may be caused by nearby high-voltage power lines.

Depending on the type of signal amplification, there are several other types of outdoor antennas. Passive outdoor antennas belong to the class of the simplest passive devices, since their design does not contain components capable of amplifying the TV signal.

IN active antennas The signal is amplified due to the presence of a special microcircuit in them. Amplifiers can be either built into the antenna structure or independent of it.

Types of antenna amplifiers

When selecting a television signal amplifier, it is necessary to take into account its technical parameters:

Frequency range. The majority of antennas sold on the domestic market are designed to work with local frequencies. However, there are exceptions.
Gain. For the meter range this figure is 10 dB, and for the decimeter range - from 30 to 40 dB.
Noise figure. The recommended size is no more than three decibels.

The secondary parameters in the selection process are supply current (from 30 to 60 mA) and voltage (from 5 to 12 V). There are also differences in the place where the amplifier is located (directly on the receiver or near it).

However, even the use of components High Quality and reliably operating equipment does not always guarantee satisfactory quality of received television programs. This indicator may be negatively affected by low-quality coaxial cable, used for connection, and poor-quality elements for its connection. It is recommended to purchase a cable that has a thick central core and a standard characteristic impedance of 75 Ohms.

In addition, sources of interference in the picture may be Appliances and external sources. The latter are most often radio stations and cellular transmitters. There is only one protection against them - antennas with a narrow radiation pattern.

Antenna reception of signals digital television broadcasting or analog is not significantly different. It’s just that for digital it is necessary to support the UHF range, provided that there is a DVB-T/T2 receiver in the TV itself. If it is not there, you will have to purchase an external TV tuner.

In conclusion, let's say a few words about satellite dishes. The diameter of their bowls can range from fifty centimeters to five meters. The sensitivity of the antenna is directly dependent on the size. Correctly installing and configuring a satellite dish is not at all easy, and therefore the involvement of highly specialized specialists is necessary to carry out this work.

After working at your site during the day, in the evening you want to relax and watch an interesting film or evening concert on television.

But often, especially for summer cottages remote from large cities, the pleasure of viewing is sharply reduced due to Bad quality reception of a television signal. In this case, more attention needs to be paid to the television antenna. Let's figure out when you might need an amplifier for a TV antenna in the country and how to choose it.

Currently, satellite dishes or antennas are used to receive television signals in suburban areas. terrestrial television.

Satellite dishes

A good solution to the problem of getting quality signal is the use satellite dish. Satellite channels televisions broadcast television programs from satellites and do not depend on terrestrial television transmission centers. Modern satellite television covers the entire Earth. You only need to purchase and install a satellite dish with the appropriate equipment.

Advantages of satellite dishes:

receive a large number of TV channels;
reception does not depend on the terrain;
have a low weight structure;
do not require special maintenance.

A typical receiving satellite antenna consists of a reflector, which is a so-called dish (paraboloid of rotation) and an irradiator (receiver) installed at its focus. More often used offset antennas, in which the focus is located below the geometric center of the antenna, which increases its stability and sensitivity. The received high-frequency signal is amplified and converted, and then transmitted through cables for further conversion into a television signal.

A satellite antenna can have a diameter from 0.55 to 5 m. Depending on this diameter, the sensitivity of the antenna also changes.

To receive programs from various satellites, sets of satellite receiving systems are available. For example, satellite dish kits are sold that allow you to connect to the most popular television satellites"Tricolor" or "NTV-Plus".

Installing and configuring a satellite dish is quite a complex job, so in most cases it is better to contact a specialized company to install a satellite dish, although this is an expensive undertaking. For example, a set satellite television“Tricolor TV” with the GS 6301 receiver costs 7,190 rubles, and with installation - 9,700 rubles.

Terrestrial television antennas

More common for country houses and cottages are terrestrial television antennas.

Terrestrial television antennas can be indoor or outdoor.

Indoor

can be used if the cottage is located close to the repeater and the level of the received signal is quite high. When receiving a signal with an indoor antenna, there are a number of features. These features include:

weakening of the signal inside the building;
multiple reflections of this signal from various objects.

As a result of reflections at different points in the room, the signal has different magnitudes. Therefore, when using an indoor antenna, it is necessary to determine the most effective location for its installation.

Indoor antennas come in frame and rod types. The former operate in the decimeter range, and the latter in the meter range.

External

If you are far away from the repeater, you must use an external antenna.

Main characteristics of antennas:

operating frequency range;
antenna radiation pattern;
gain;
input resistance.

The operating frequency range of the antenna determines the range in which the antenna provides all specified characteristics. The radiation pattern determines the directional actions of the antenna and is measured by the width of the main lobe at some given level. The gain shows how this antenna amplifies the signal compared to a simple antenna. Gain is measured in decibels.

Antenna input impedance varies by design and affects matching with the rest of the circuit. If this impedance differs from the standard characteristic impedance of 75 Ohms, then a special high-frequency transformer is used to match the antenna.

External antennas come in the following types:

half-wave vibrator;
wave channel;
log-periodic;
common mode antenna array.

Half-wave vibrator represents the simplest antenna with a gain of 1 dB and a figure-of-eight pattern in the plane of the antenna.

Antenna - wave channel consists of an active vibrator, reflector and large number directors, which form a narrow antenna radiation pattern.

To cover a wide decimeter range it is used log periodic antenna , consisting of a large number of vibrators of different lengths. A wide operating band in such an antenna is ensured by the fact that at each frequency its own vibrators are excited, ensuring reception of a given frequency. Other vibrators do not affect the operation of the antenna at this frequency.

Example common mode antenna array The so-called “Polish” antennas of the ASP-8 type, which were very common in dachas back in the 90s and continue to be sold today, can serve. Such an antenna is a system of omnidirectional antennas spaced apart in space. Due to the phase difference, a narrowly directional diagram is formed. The antenna covers the range of television channels from No. 6 to No. 69, has a gain of 14 dB and an input impedance of 75 Ohms.

Combined

In order to cover the meter and decimeter wavelength ranges, combined antennas are also used. For example, in antennas such as “Locus” or “Delta” a vibrator is used for the meter wavelength range, and a log-periodic antenna for the decimeter wavelength range.

Factors affecting television signal deterioration

Outside the city, even a very expensive TV sometimes produces poor image quality. The reasons for poor image quality may be the following:

long distance of the TV from the broadcaster;
poor quality connecting cable;
presence of artificial or natural interference.

At weak signal Noise appears on the TV screen that is usually not visible. If they look like “snow”, then these are the noises of the TV amplifier. In order to increase the signal in this case, it is necessary to adjust the orientation of the antenna or increase its installation height. If these measures do not help, then if you are far away from the transmitter, you can try using an antenna signal amplifier.

The signal at the TV input may be weakened due to poor quality connecting cable. For example, when connecting cable sections by twisting. In any case, connections can only be made by soldering. And it is best that the cable is intact from the antenna to the entrance to the television receiver. If the cable has worked for more than 20 years, it is recommended to replace it.

If stripes, loss of synchronization, or shaking images appear on the TV screen, then, apparently, interference is passing through to the TV. This interference may be due to the operation of household electrical appliances and the operation of external sources, such as radio stations, cellular transmitters, electric train sparking and the like. If Appliances can be turned off, then you can tune out external sources by using antennas with a narrow radiation pattern.

Using an antenna amplifier

When the TV is located at a great distance from the TV broadcaster, a weak TV signal can be increased using antenna amplifier.

Most commercially available television antennas are active. This means that they include an antenna amplifier.

An example is a Polish-made antenna of the ASP-8 type. This antenna offers several amplifier options with different gains. The type of amplifier is selected depending on the distance between the broadcaster and the television antenna.

The gain of the amplifier in the UHF range (21-60 channels) is 30-40 dB, in the meter range (1-12 channels) it is about 10 dB, and the noise figure of the amplifier is 3 dB. Power is supplied from a separate stabilized source of 12 V with a current consumption of 65 mA.

When choosing an antenna amplifier, you need to consider the following parameters:

gain in decibels (dB);
noise figure in dB;
supply voltage;
current consumption.

To reduce the influence of loss noise in the supply cable, the amplifier is mounted directly on the antenna. Power is supplied to the amplifier transistor through a coaxial cable. The price of such an amplifier is only 120 rubles.

Setting up the amplifier is done by selecting the appropriate type of amplifier. At the same time, sellers usually give a couple of weeks to check the amplifier in the antenna. During this time, it is allowed to replace the purchased amplifier with another. Experience shows that sometimes when tuning it is necessary to slightly change the gain by adjusting the supply voltage. But this must be done carefully so as not to damage the amplification device.

DIY antenna amplifier

If you wish, you can assemble the antenna amplifier yourself. For example, a broadband amplifier circuit for the range 30-850 MHz using imported S790T transistors is proposed. The amplifier is a two-stage resistor-based amplifier. Each stage provides a gain of 10 dB.

The amplifier is powered from a source direct current with a voltage of 9−12 V. The circuit is designed as printed circuit board. It can be installed near the TV.

Antenna for digital television reception

In accordance with Federal program The country is transitioning to digital television. IN Lately masts of such television are installed in different parts of the country. For example, in the city of Zaraysk, Moscow region, a mast was installed digital broadcasting, with the help of which free transmission of RTRS-1 channel packages is carried out on channel 59 with a frequency of 778 MHz. The package includes 10 of the most famous channels.

In order to receive digital television at the dacha with an antenna operating in the UHF wavelength range, there is no need to upgrade it. If you have a TV with a built-in DTV-T2 tuner, no changes need to be made. In other cases, the upgrade concerns the TV, to which you need to connect the DTV-T2 tuner set-top box.

When receiving television programs in a country house, various interference often occurs and the image deteriorates.
To receive high-quality TV programs in your dacha, you must have good antenna — satellite dish or a high quality outdoor antenna.
To increase the value of the received signal, it is necessary to use antenna amplifiers, and to tune out interference, an antenna with a narrow radiation pattern.
Outdoor UHF antennas are quite suitable for receiving digital television, but for an old TV you need to connect a DTV-T2 tuner set-top box.

The following video will help you decide on the choice of antenna amplifier: