TV antenna signal amplifier by hand. TV signal amplifier: what is it and what is it for. Why DMV

Despite the rapid development of satellite and cable television, the reception of terrestrial television broadcasts still remains relevant, for example, for places of seasonal residence. It is not at all necessary to buy a finished product for this purpose; a home UHF antenna can be assembled with your own hands. Before moving on to considering the designs, we will briefly explain why this particular range of the television signal was chosen.

Why DMV?

There are two good reasons to choose designs of this type:

The thing is that most channels are broadcast in this range, since the design of repeaters is simplified, and this makes it possible to install a larger number of unattended low-power transmitters and thereby expand the coverage area.
This range is selected for digital broadcasting.

Indoor TV antenna “Rhombus”

This simple, but at the same time, reliable design was one of the most common in the heyday of on-air television broadcasting.

Rice. 1. The simplest homemade Z-antenna, known under the names: “Rhombus”, “Square” and “People’s Zigzag”

As can be seen from the sketch (B Fig. 1), the device is a simplified version of the classic zigzag (Z-design). To increase sensitivity, it is recommended to equip it with capacitive inserts (“1” and “2”), as well as a reflector (“A” in Fig. 1). If the signal level is quite acceptable, this is not necessary.

The material you can use is aluminum, copper, and brass tubes or strips 10-15 mm wide. If you plan to install the structure outdoors, it is better to abandon aluminum, since it is susceptible to corrosion. Capacitive inserts are made of foil, tin or metal mesh. After installation, they are soldered along the circuit.

The cable is laid as shown in the figure, namely: it did not have sharp bends and did not leave the side insert.

UHF antenna with amplifier

In places where a powerful relay tower is not located in relative proximity, you can raise the signal level to an acceptable value using an amplifier. Below is circuit diagram device that can be used with almost any antenna.

Rice. 2. Antenna amplifier circuit for the UHF range

List of elements:

Resistors: R1 – 150 kOhm; R2 – 1 kOhm; R3 – 680 Ohm; R4 – 75 kOhm.
Capacitors: C1 – 3.3 pF; C2 – 15 pF; C3 – 6800 pF; C4, C5, C6 – 100 pF.
Transistors: VT1, VT2 – GT311D (can be replaced with: KT3101, KT3115 and KT3132).

Inductance: L1 – is a frameless coil with a diameter of 4 mm, wound copper wireØ 0.8 mm (2.5 turns need to be made); L2 and L3 are high-frequency chokes 25 µH and 100 µH, respectively.

If the circuit is assembled correctly, we will get an amplifier with the following characteristics:

bandwidth from 470 to 790 MHz;
gain and noise factors – 30 and 3 dB, respectively;
the value of the output and input resistance of the device corresponds to the RG6 cable – 75 Ohm;
the device consumes about 12-14 mA.

Let's pay attention to the method of power supply; it is carried out directly through the cable.

This amplifier can work with the simplest designs made from improvised means.

Indoor antenna made from beer cans

Despite the unusual design, it is quite functional, since it is a classic dipole, especially since the dimensions of a standard can are perfectly suitable for the arms of a decimeter range vibrator. If the device is installed in a room, then in this case it is not even necessary to coordinate with the cable, provided that it is not longer than two meters.

Designations:

A - two cans with a volume of 500 mg (if you take tin and not aluminum, you can solder the cable instead of using self-tapping screws).
B – places where the cable shielding is attached.
C – central vein.
D – place of attachment of the central core
E – cable coming from the TV.

The arms of this exotic dipole must be mounted on a holder made of any insulating material. As such, you can use improvised things, for example, a plastic clothes hanger, a mop bar or a piece of wooden beam of appropriate size. The distance between the shoulders is from 1 to 8 cm (selected empirically).

The main advantages of the design are fast production (10 - 20 minutes) and quite acceptable picture quality, provided there is sufficient signal power.

Making an antenna from copper wire

There is a design that is much simpler than the previous version, which only requires a piece of copper wire. We are talking about a narrow band loop antenna. This solution has undoubted advantages, since in addition to its main purpose, the device plays the role of a selective filter that reduces interference, which allows you to confidently receive a signal.

Fig.4. A simple UHF loop antenna for receiving digital TV

For this design, you need to calculate the length of the loop; to do this, you need to find out the frequency of the “digit” for your region. For example, in St. Petersburg it is broadcast on 586 and 666 MHz. The calculation formula will be as follows: L R = 300/f, where L R is the length of the loop (the result is presented in meters), and f is the average frequency range, for St. Petersburg this value will be 626 (the sum of 586 and 666 divided by 2). Now we calculate L R, 300/626 = 0.48, which means the length of the loop should be 48 centimeters.

If you take a thick RG-6 cable with braided foil, it can be used instead of copper wire to make a loop.

Now let's tell you how the structure is assembled:

A piece of copper wire (or RG6 cable) with a length equal to L R is measured and cut.
A loop of suitable diameter is folded, after which a cable leading to the receiver is soldered to its ends. If RG6 is used instead of copper wire, then the insulation from its ends is first removed, approximately 1-1.5 cm (the central core does not need to be cleaned, it is not involved in the process).
The loop is installed on the stand.
An F connector (plug) is screwed onto the cable to the receiver.

Note that despite the simplicity of the design, it is most effective for receiving “digits”, provided that the calculations are carried out correctly.

Do-it-yourself MV and UHF indoor antenna

If, in addition to UHF, there is a desire to receive MF, you can assemble a simple multiwave oven, its drawing with dimensions is presented below.

To amplify the signal, this design uses a ready-made SWA 9 unit; if you have problems purchasing it, you can use a home-made device, the diagram of which was shown above (see Fig. 2).

It is important to maintain the angle between the petals; going beyond the specified range significantly affects the quality of the “picture”.

Despite the fact that such a device is much simpler than a log-periodic design with a wave channel, it nevertheless shows good results if the signal is of sufficient power.

DIY figure eight antenna for digital TV

Let's consider another common design option for receiving “digits”. It is based on the classic scheme for the UHF range, which, because of its shape, is called “Figure Eight” or “Zigzag”.

Rice. 6. Sketch and implementation of the digital eight

Design dimensions:

outer sides of the diamond (A) – 140 mm;
inner sides (B) – 130 mm;
distance to the reflector (C) – from 110 to 130 mm;
width (D) – 300 mm;
the pitch between the rods (E) is from 8 to 25 mm.

The cable connection location is at points 1 and 2. The material requirements are the same as for the “Rhombus” design, which was described at the beginning of the article.

Homemade antenna for DBT T2

Actually, all of the examples listed above are capable of receiving DBT T2, but for variety we will present a sketch of another design, popularly called “Butterfly”.

The material can be used as plates made of copper, brass, aluminum or duralumin. If the structure is planned to be installed outdoors, then the last two options are not suitable.

Bottom line: which option to choose?

Oddly enough, the simplest option is the most effective, so the “loop” is best suited for receiving a “digit” (Fig. 4). But, if you need to receive other channels in the UHF range, then it is better to stop at “Zigzag” (Fig. 6).

The antenna for the TV should be directed towards the nearest active repeater, in order to select the desired position, you should rotate the structure until the signal strength is satisfactory.

If, despite the presence of an amplifier and reflector, the quality of the “picture” leaves much to be desired, you can try installing the structure on a mast.

In this case, it is necessary to install lightning protection, but this is a topic for another article.

This wideband amplifier has a total gain of 10 to 15 dB in the frequency range 400 - 850 MHz. UHF can be used where the television signal is too weak to make do with just one, even a good, antenna. For reliable operation of the antenna amplifier, you need to cut the contacts as short as possible. Capacitors C1, C2, C6, C7 SMD type (surface mount). The antenna amplifier must be assembled inside a metal box and then connected next to the TV antenna.

Scheme printed circuit board for a TV antenna amplifier using a 2sc3358 transistor.

Amplifier components:

T1 transistor 2sc3358
C1 - 10mF/35v C2, C9 - 1nF C3, C4 - 10 nF C5, C6, C7, C8 - 10 pF
R1 - 470 Ohm R2 - 2.2 kOhm, R3 - 1 kOhm, R1 - 5 kOhm
L1, L2 - 2 turns 0.5 mm, 3 mm. L3, L4 - 10uH or 10 turns, 0.2 mm on ferrite.
12 volt power supply.

The amplifier operates from a 12V power source. A simple stabilized source is enough - a diode bridge and a 1000 μF electrolyte. The TV antenna amplifier can be connected directly to the power source via a coaxial cable, but do not forget about the 10 - 100uH choke on the power line. The TV will be connected to the amplifier through a small capacitor. The adjustment is very simple, just move resistor P1 to the middle and then adjust it when you receive best quality images on the screen.

In modern conditions, the transmission of a television signal and the transmission of images to the screen can occur with interference, which affects the quality of the image transmission. To solve this problem, you can use antenna amplifier for TV.

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What is an antenna amplifier and how does it work?

An active antenna amplifier for a home TV for a summer cottage or a compact TV in a car is a device used to increase the level of the received signal. Using a TV amplifier will correct the situation if the owner of the house has chosen the wrong model antenna adapter

to a satellite dish or cable television.

The adapter structurally consists of two transistor components, which are installed in the housing and connected according to a special circuit. Its use will reduce the amount of noise generated during the operation of a television device. In order to adjust the device to work in a specific frequency range, a special capacitor is used, which is installed in the oscillating circuit.

The ChipiDip channel spoke in detail about the principle of operation of the amplification device.

The input circuit of the circuit is placed on special elements and is a high-frequency filtering device. The frequency value at which it operates is approximately 48.5 MHz on the first band and around 160 MHz on the second. The use of resistor circuit elements allows you to set the operating mode.

The adapter itself can operate from a 12-volt power source, which allows it to be installed in cars. To ensure correct operation, the device can operate from a diode bridge and an electrolyte rated at 1000 μF.

The test of the T2 antenna amplifier is shown in the video from the Rem Zone channel.

One of the main characteristics of the device is the presence of two identical stages that provide signal amplification. These components are installed on special transistor elements with low noise levels. New TV devices may not have such amplifiers, but in order to avoid the problem of a bad signal in the future, it is still better to install them.

Varieties

Indoor and outdoor antenna devices that allow you to receive and amplify a television signal can be of several types.

Broadband

These devices can be used to improve the quality of the receiving signal on several television devices simultaneously. They are widely used in everyday life and are often installed in the entrances of apartment buildings. This type of amplification device can operate in two ranges - MV and UHF.

Band

Allows you to receive signals from stations located at great distances. Band type antenna amplifiers can improve image reception quality while eliminating interference.

Multi-band

Allows you to improve the quality of the signal transmitted to the TV from receivers located on high masts. Devices of this type have found application in televisions operating in small collective reception systems.

The “Garden at All Latitudes” channel provided a review of a high-quality amplification device that allows you to work with long distances.

How to choose a signal amplifier for your TV

To choose a high-quality antenna amplifier for your TV, when purchasing you need to base your purchase on the following parameters:

Gain value or antenna coefficient, this parameter- not less than 40 decibels. This indicator must be calculated in advance, taking into account the approximate distance between the mast where the signal source is installed, and the TV. The gain of the device is no more than 150 kilometers. If the distance between your TV and the antenna mast is less than 10 kilometers, then there is no point in increasing the quality of the received signal, you just need to purchase the type of antenna that is suitable for you. If there are more than ten kilometers between the TV and the tower, then you should not buy an amplifier with a coefficient greater than required. This can lead to a conflict and provoke the opposite effect; as a result, there will be no high-quality picture on the screen and interference will appear.
Type of antenna used. For example, if you have an array antenna installed, an SWA type amplification device will do.
The frequency range in which the antenna operates. For an external receiver, the best option would be a broadband amplifier, since it allows you to receive frequencies in any range. But in fact, devices designed to operate in a specific range show good results in terms of receiving signals without interference.
Noise figure. With a low setting, the image quality will be higher. Buy amplifiers with minimal noise factor. It is recommended that this value be no higher than 3 decibels.
Parameter of the signal at the device output. Practice shows that the best option in this matter would be amplifiers operating with 100 decibels per microvolt.
Amount of current consumption. Experts advise buying devices rated at 30-60 amperes.

The ChipiDip channel talked about the features of the choice and reviewed several popular models of antenna amplifiers for connecting to a TV.

Advantages and disadvantages

Advantages of amplification devices:

Thanks to the operation of the amplifier, television equipment will be able to receive even the most weak signal from the towers
With the right choice, you can achieve a minimum noise figure. This ensures high-quality signal reception with little interference.
Possibility of improving image quality over a wide frequency range in various ranges.
Large selection of devices on the market. The consumer can purchase an amplification device according to his preferences and budget.
Easy to install. To use, the consumer only needs to connect the cable to the device and connect the wire from it to the TV.

Disadvantages specific to amplifiers:

Possibility of overloading the TV due to receiving powerful impulses in the meter range.
The probability of self-excitation of the device. Ultimately, this may cause it to break.
Boosting devices may be susceptible to lightning current. In the absence of an additional fuse, this may damage the television equipment.
Passive losses may appear at the output of amplifying devices.

Where to buy and how much it costs

According to reviews, the price of the device directly depends on:

manufacturer;
type;
technical characteristics;
quality of execution.

You can purchase an antenna amplifier in a specialized store, on the market, or from online sellers. The cost of the cheapest devices today is about 500 rubles. The most expensive options can cost the buyer 2-4 thousand rubles.

How to make an antenna amplifier with your own hands

You can build an amplification device for television equipment yourself.

Roman Nochnoy told how to improve a working antenna amplifier to avoid interference during a thunderstorm.

What materials will be needed?

To create a device you will need:

power cord, length determined by owner;
a special connector through which the device must be connected;
two tin cans, suitable for beer or other drinks;
two self-tapping screws;
electrical tape or tape;
wooden stick, an old trempel will do.

Scheme

You can assemble the device based on one of the diagrams below.

First scheme

Let's start with a description of the simplest one:

VT—microboard MAX2633;
R - resistor element per kilohm;
C1, C2 and C3 are capacitor devices, each rated at 1 nF.

The board is powered from a constant current source, the voltage of which ranges from 2.8 to 5.2 volts. The first scheme is characterized by a reduced noise level of about two decibels, as well as good parameter gain - approximately 13 decibels. If you need to reduce this parameter, you can increase it using a resistor device.

The main advantage of the circuit is that there is no need to configure it after assembly; in practice, such devices are excellent for connecting to radios and apartment TVs. This circuit is not broadband, despite the misconception of many experts, since it was originally intended for the VHF range.

Second scheme

Designations of the second scheme:

VT1 — transistor device KT368;
resistance elements made in the form of resistors, R1 and R4 - designed for 100 Ohms, R2 - for 470 Ohms, R3 - for 51 kOhms;
capacitor elements, the first of which is rated at 1000 pF, the second at 33 pF, and the third and fourth (C3 and C4) at 15 pF each.

The Engineerium channel talked about the creation and assembly of an amplifying device for receiving digital signals.

The special feature of this antenna amplifier board is that it is easy to assemble and does not require any configuration.

The gain, as well as the frequency properties of the device, depend on the installed transistor elements. Transistors have high gain and low frequency properties. The device is powered from a source supplying a voltage of 9 volts. This method with the connection of a transistor device is characterized by a reduced gain and an extended frequency range.

Third scheme

Designations of the third scheme of the “common” base:

VT1 - transistor device, KT315 board;
resistor components, each of which is designed for a specific resistance: R1 - 51 Ohm, R2 - 10 kOhm, R3 - 15 kOhm and R4 - 1 kOhm;
capacitor devices, their operating parameters are the same as those of the capacitors for the previous circuit.

In this case, the inductor must be wound on a special ferromagnetic ring, its permeability value will be 600 N. If the range is meter, then three hundred turns will need to be made, and the power cable must be used only PEF with a diameter of less than 0.1 mm.

Fourth scheme

If you need to achieve a higher gain, then you can assemble an amplification device using a two-stage circuit, but this option is more complex in terms of execution:

VT1 and VT2 - two boards of the GTZ11D standard;
resistor devices, the first is designed for 680 Ohms, the second - for 75 kOhms, the third - for 1 kOhms, and the fourth - for 150 kOhms;
capacitor elements - the first, second and fourth are designed for 100 pF, the third - for 6800 pF, the fifth - for 15 pF, and the sixth - for 3.3 pF;
choke devices, the first is designed for 100 μH, the second for 25 μH, and the third is made in the form of a coil on a frameless base with a diameter of 4 mm.

Two and a half turns are wound on the last coil, and the connection cable complies with the PEV standard with a diameter of no more than 0.8 mm. The circuit is powered from a 12-volt source. There is no need to configure the amplifier device.

Photo gallery

1. The first diagram for assembling the amp 2. Second option for assembling the circuit for the amplifier 3. Diagram of the “common” base for amplifier assembly 4. Complex circuit of a two-stage device

Step-by-step assembly instructions

Regardless of the circuit, the amplifier is assembled in the following order:

Two tin cans along with a stick from an old trempel must be connected to each other using electrical tape. Please note that the distance between the cans will be approximately 7 cm. If the cans have rings, you can fix the power cord to them.
Then you need to screw self-tapping screws into the cans. To do this, the ends of the power wire should be trimmed with a utility knife. After this, the cable is fixed with screws.
Using electrical tape, you need to connect the stick to the power cable. This will make the amplifier device more stable.
Tin cans need to be covered with a plastic flask. You can make it by cutting out the middle of an ordinary bottle, removing the neck and bottom.
A hole must be made in the central part of the container; a wire will be laid through it.
All elements are fixed and soldered on the board in accordance with the diagram. After assembling the device, pour a little boiling water onto the nylon bottle. This will give the device the required shape and ensure high-quality tightness of the hole through which the wire passes.
Then the amplifier device is connected. For the above circuits, amplifier tuning is not required, but it will be relevant if other options are used. After setup, the device will function flawlessly.

How to connect an amplifier to a TV?

The easiest option to improve the quality of a weak signal at home transmitted via communication channels is to install the device in close proximity to the TV. If you place the device at a great distance, then in conditions of remote reception it will not be possible to increase and increase the quality of the signal.

The adapter can be connected using a coaxial wire conventional antenna for TV, but for this purpose a special choke is located along the power supply line. To improve the effect of a powerful amplifier, the device is connected to a TV device through a low-capacity capacitor element. The adjustment procedure is carried out quickly; to do this, the resistor element must be moved to the middle and adjusted so that the picture quality on the device is optimal.

How to connect a homemade or branded amplifier device, for example, from the manufacturer Delta or any other brand:

The amplification device must be installed as close as possible to the television equipment. This is due to the presence of losses, which can lead to deterioration in the quality of the broadcast image. This requirement is relevant for homemade devices and branded amplifiers. The exception will be indoor devices that have a short power cord. But such devices are usually used within a reception radius, where there is no need to use an amplification device.
Before connecting, you must carefully study the service manual. It may describe certain nuances.
If after the antenna amplifier the quality of the broadcast image has not improved, then you need to check the integrity of the antenna itself. Perhaps the reason for incorrect operation is a frequency mismatch.
All actions regarding connection must be carried out with de-energized electrical appliances and equipment.

Connecting a TV amplifier without lightning protection for the antenna is not allowed.

Review of popular models

The “Garden at All Latitudes” channel provided a review of a high-quality television signal amplification device with a range of more than two hundred kilometers.

Popular models of amplification devices:

Delta K331. The device of this model is characterized by a different gain for each individual range. For a narrowband format this is about 14 dB, for HF it is about 6 dB. The highest quality signal can be provided with digital broadcasting. To operate in such a wide frequency range, the device is equipped with separate wireless devices, which allows for better quality of the broadcast image. General parameter gain depends on the characteristics of the antenna device itself. Due to the different polarization of radio and television broadcasts, for tuning in the first case, the antenna is installed sideways, but the television signal will disappear, and vice versa.
Televes 5523. Italian-made antenna amplifier, equipped with five outputs. It is characterized by an increased gain of 16 decibels, which reduces the likelihood of interference and noise. To operate the device, you will need a power source included in the package.
Satellite signal amplifier Gecen A05-02. The reception quality when installing this model of device will be up to 21 dB. The device works perfectly in the ranges from 5 to 950 MHz for terrestrial television and in the range from 950 to 2400 /MHz for satellite television. Power is provided by the broadband device and is supplied via coaxial wire from the receiver. To obtain better image quality of the on-air signal, you will need to additionally purchase another power source.
SWA amplification devices. Such devices are mounted mainly on grid devices and are characterized by different gain factors depending on specific model. The devices can operate in the frequency range from 49 to 790 MHz. The supply voltage is 9 volts. The device is installed using a threaded connection.

Why does the amplifier not work and what should I do?

Failure of amplifier devices usually occurs for several reasons:

lightning strikes the antenna, causing transmission static electricity via device;
overvoltage, as a result of which the power supply breaks.

The photo below shows the board from the SWA-2000 device; the transistor elements that are used for amplification and protection are demonstrated here.

SWA-2000 device board

When a lightning strike occurs on an antenna, the first thing to fail on such boards is usually the transistor device in the first stage and the capacitor element. To repair cascade 1, it is recommended to use transistor devices with an F-cutoff frequency of 1.4 - 3 GHz and a reduced intrinsic noise.

For example, details:

KT391A-2;
KT3101A-2;
KT3115A-2, etc.

Their use does not contribute to the deterioration of noise properties, but the use of devices 2T3124A-2, KT3132A-2 and other similar ones will reduce this parameter to 1.5 decibels. Therefore, it is advisable to install such transistor devices on working boards, this will ensure high-quality signal reception in the presence of interference.

To repair the second cascade, the use of cheaper, but still powerful devices is allowed:

KT391A-2;
KT371;
KT399 and others.

It is important that the cutoff frequency of the transistor elements be 2 GHz.

If difficulties arise in performing repairs or choosing transistor devices, you can install KT399 and KT316 elements in cascades; these are common models. Their use will not lead to a decrease in the quality of the transmitted signal. Installation of new parts is carried out on the opposite side of the circuit; for installation it is necessary to drill holes in the board with a diameter of no more than 0.8 mm. You need to drill the circuit so that the hole touches the edge of its surface.

Video “How to drill an amplifier board correctly?”

M Khromov showed how, when repairing an amplification device, to correctly drill a microcircuit using a tester so as not to damage the internal elements of the board.

The receiving television antenna receives electromagnetic radiation from the television center, which induces currents on its conductive elements that enter the coaxial cable. Depending on the design of the antenna with directional properties, it is possible to obtain a signal of different strengths. In this regard, the concept of the directional coefficient of a TV antenna is introduced, which shows how many times the signal at its output exceeds the signal from a half-wave vibrator if it is placed in the same place in space.

TV antenna with amplifier

The actual power gain taking into account losses will be:

K p = KND∙η,

where η is the efficiency factor taking into account losses.

Application

The level of the electrical signal coming through the TV antenna input does not always suit the user. To improve the performance of the receiver, you need a signal amplifier located nearby. It is especially required outside the city, where there is no cable network.

At the dacha, signal reception conditions are worse than in the city. It is affected by interference and distance from the television center. Despite the fact that a TV amplifier slightly distorts the input signal, experts recommend using it.

In high-rise buildings, the signal comes from top to bottom and weakens significantly at the end. If it has low power, it is largely attenuated to the connection socket. In the cable, the signal is lost by 0.2-0.7 dB/m.

Amplifier selection

The antenna amplifier is connected as close as possible to the TV antenna. Placing it near the receiver will increase the noise along with the transmitted signal, and the image will be worse. The power supply can be placed near the amplifier, or separately.

Home antenna made together with an amplifier

Parameters that determine right choice amplifiers are as follows:

distance from the television center;
required frequency range;
the type of antenna for which the signal is amplified.

The maximum distance to the signal transmission source should not exceed 150 km. At a distance of less than 10 km, an amplifier is usually not installed, since the signal level is quite high. To obtain a normal signal, it is advisable to choose a good antenna. How to make a TV antenna with your own hands from wire.

The gain should not be too high, otherwise significant noise may appear from self-excitation. Many models produced have different characteristics. Here you should contact a specialist who knows how to improve the technique and will help you choose required device. Installing a broadband amplifier on the antenna makes it possible to cover the entire television broadcast range.

In Russia, antennas with amplifiers made in Poland (ANPREL) are common. Their own gain is small, and the parameters are mainly determined by the additional amplifier. It has the following disadvantages: self-excitation, high level of generated noise, overload from powerful signals in the MV range, damage from lightning discharges, passive output losses.

In most TV amplifiers, they operate according to a standard two-stage circuit based on bipolar transistors high frequency with a common emitter.

Amplifiers on two stages: SWA-36 (a) and SWA-49 (b)

The amplifier stage captures the wideband band. The input signal is fed to the base of the transistor (T1) through a capacitor (C1). The necessary linear characteristic in it is created by applying a bias voltage through a resistor (R1). But at the same time the gain decreases. The next stage is created according to a similar circuit with stabilization of the transistor (T2) in the emitter circuit by feedback through a resistor (R4).

It is not recommended to significantly increase the Kp of the antenna amplifier, since it creates its own noise, which increases along with the input signal. It is not difficult to make the circuit yourself.

You can improve the circuit using the SWA-49 model. This is ensured by using filters L1C6, R5C4 and increasing Kp by adding capacitors (C5) and (C7).

Other ANPREL models differ slightly from the above diagrams in the presence of frequency correction circuits at the output and organization feedback, on which the gain value depends. If it is close to the stability threshold, there is a high probability of self-excitation of the amplifier.

TVs themselves have significant signal amplification. The larger it is, the higher the intrinsic noise becomes. Therefore, it is necessary to understand that reception capabilities may be influenced to a greater extent by their own noise interference than by a weak signal at the input. The signal must be at least 20 times higher than the noise voltage. Closer to this value the image becomes poor and fine details can no longer be distinguished.

The transistor of the first stage has the maximum influence on the self-noise level of the antenna amplifier. Amplifiers should be selected correctly based on noise level, which should not exceed 2 dB. It may not be indicated in the instructions, but it can be found on the Internet or company catalogs.

The gain is needed mainly to compensate for losses in the cable. They are especially large on channels 21-60 and amount to 0.25-0.37 dB/m. An industrial splitter adds losses, which are indicated on the housing. It should be taken into account that the indicated signal attenuation value (usually 3.5 dB) may differ at different wavelength ranges. This may be the maximum or average value. In any case, you need to take a factory product, not a homemade one. Then 12-14 dB should be added to the total attenuation so that weak signals are captured.

What does an antenna splitter look like?

Antenna signal power

There may be several reasons for the weakening of the signal from a satellite dish:

Failure to adjust the antenna position. Sometimes it is enough to turn it just a little. If the fastening screws are loose, they should be tightened.
The appearance of an unexpected obstacle that must be removed or the antenna location changed.
Cable failure. The best option is its replacement. It is important to make a good fastening so that it does not dangle from the wind.
Excessive cable length. A better quality one is selected or an amplifier is installed.
If everything is in order, but the signal is not enough, you should purchase an antenna with a larger diameter.

A signal amplifier for a satellite TV antenna is installed between it and the receiver. With a cable length of 40 m, the signal attenuation will be 40x0.37 = 14.8 dB, and with a splitter - 18.3 dB. The receiver input level is 48-75 dB. If it is close to the lower limit, an amplifier will be needed. If we take a 20dB IF model, it has a gain of 20 dB, which is sufficient to compensate for attenuation.

The frequency range of satellite antennas is 950-2400 MHz, for which this amplifier is suitable (Fig. below a). You can also purchase the Gecen A05-20 model with similar parameters (Fig. b).

Satellite antennas (a) and amplifier for them (b)

You should purchase amplifiers designed for the frequency range of a television antenna. The upper limit for terrestrial television is 950 MHz, and for satellite - 2400 MHz.

DIY amplifier

Even a beginner can assemble a simple device on a microcircuit with his own hands. It does not create much interference, consumes virtually no energy and operates at frequencies up to 900 MHz.

Amplifier chip that you can assemble yourself

The basis of the circuit is a low-noise low-voltage amplifier microcircuit (power supply 2.7-5.5 V). The circuit consumes only 3 mA current. Voltage is supplied to input (1). The displacement into the working area is created by a resistor (R1) connected to the input (2). The input signal from the antenna arrives at pin (6), and the amplified signal is removed from pin (3) and goes to the receiver. Capacitors (C1-C3) are added to the microcircuit, separating alternating signals from the direct component of the power source voltage. If assembled correctly, the circuit does not need to be configured.

You can also make devices with your own hands according to the previously given schemes, for example, such as SWA amplifiers.

How to improve the signal. Video

The video below will tell you how to improve the signal of a television antenna.

It is better to purchase factory-made antennas and TV amplifiers, since they are made according to calculations. If you make the devices yourself, their quality will be an order of magnitude lower. For TV reception in the country you need to have devices High Quality due to the distance from the television center and the availability large quantity interference

Kirill Sysoev

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Content

The device is used to improve the quality of reception of television channels on the antenna. As a rule, amplifiers are used in the decimeter or meter range, but they can also be installed at a considerable distance from the receiver.

What is an antenna amplifier

To increase the signal reception level of the antenna, an amplifier is connected to it. It is useful in cases where the distance from the television center to the receiver is significant or the wrong model of cable or satellite antenna is selected. Using the device you can significantly improve the quality of the picture shown on your TV. The installation is considered correct of this device directly next to the receiver, since the signal coming from it along the cable gradually decreases. In conditions of long-distance reception, however, an amplifier located nearby will be of no use.

Types of devices

TV antenna amplifiers have different parameters and can be broadband, multi-band, or range. In addition, excellent types of devices are designed for long-range and short-range reception, and are installed next to outdoor and indoor receivers. Distinctive features different types devices:

Broadband. This type of antenna amplifier for a TV is designed to improve picture reception on several TVs at once (often installed in apartment buildings and entrances). The broadband model can operate in both UHF and HF bands.
Range. Thanks to them, you can receive a signal from very distant stations. Range models improve reception by eliminating noise.
Multi-band. Provides improved television images from receivers mounted on high masts. Multi-band devices are used in small collective reception systems.

How to choose a signal amplifier for your TV

The modern market presents many different models, for this reason, many ordinary people find it difficult to decide which device suits them best. To make the right choice, you should consider several important parameters:

Gain. It should be calculated based on the approximate distance between the TV and the signal source (tower). It should not exceed 150 km. At a distance of no more than 10 km, there is no need to amplify the signal; you just need to choose a suitable antenna. If the distance between your home and the source is more than 10 km, you should not purchase a device with a coefficient higher than necessary - this will lead to the opposite effect and instead of a high-quality image you will see new interference.
Antenna type. For example, swa models are suitable for array receivers, which operate in the frequency range from 49 to 790 MHz. Some of the most popular modern Locus models are perfectly compatible with LSA amplifiers.
Frequency range. A good solution for a conventional outdoor receiver (which receives waves of any frequency) would be to install a broadband model, but a better result is shown by a device that operates only in a certain range.
Noise figure. The lower this parameter, the better the image on the TV screen will be.

Where to buy and how much it costs

A huge selection of devices that improve the signal of television receivers is presented in online stores, points of sale of electronics, and hypermarkets with corresponding departments. The price of these devices varies greatly and depends not only on the parameters, but also on the regions where the TV antenna amplifier is sold. Average cost of popular models:

Alkad – from 800 rub.;
Luxmann - from 550-600 rubles;
Lance - from 700 rub.;
Planar - from 2000-2300 rubles;
Surmount – from 600 rub.

How to make a TV signal amplifier with your own hands

An indoor antenna with an amplifier allows you to provide a better picture on the TV screen, minimize noise and find more channels. At the same time, it is not necessary to buy a device, because it is not very difficult to make it yourself using beer cans. An amplifier for a TV antenna of this type can be made in 10-15 minutes and functions perfectly. To create it you need:

power cable;
plug;
2 tin cans;
screwdriver;
2 screws;
sticky tape/duct tape;
stick (old wooden trempel).

Scheme for creating a device for dvb:

Connect the beer cans and the stick using electrical tape, ensuring a distance between the cans of approximately 7-7.5 cm. If the cans have rings, then it is better to attach the cable to them.
Next, screw the screws into the cans, strip the ends of the cable and attach it with screws.
Use adhesive tape to connect the stick and cable to stabilize the receiver.
Cover the jars with a large plastic bottle with the bottom and neck cut off. Make a hole in the center of the container through which you can pull the cable.
When the device is assembled, pour a little boiling water onto the nylon bottle, which will help change the shape of the plastic and ensure greater tightness of the hole.
Connect the device and configure. If desired, the design can be improved by adding several sections.

Since television channels are in the UHF range, there is no need for balancing. The characteristic impedance of the half-wave vibrator is between 72 and 76 Ohms, which is in excellent agreement with the cable. To configure the receiver, you must adjust the distance between the banks. As the diameter of the wire (can) increases, the signal bandwidth will increase.

Video: how to install a digital TV signal amplifier at your dacha

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