Making an antenna for digital TV with your own hands. A simple antenna for digital television DVB-T2 with your own hands How to make a TV antenna in the country

Despite the rapid development of satellite and cable television, the reception of terrestrial television is still relevant, for example, for seasonal residences. It is not at all necessary to buy a finished product for this purpose; a home decimeter (UHF) antenna can be assembled by hand. Before proceeding to the consideration of designs, we will briefly describe why this particular range of the television signal was chosen.

Why DMV?

There are two good reasons to opt for this type of structure:

1. 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.
2. This range is selected for broadcasting "numbers".

Indoor antenna for TV "Rhombus"

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

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 the 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 acceptable, this is not necessary.

As a material, you can use aluminum, copper, as well as brass tubes or strips with a width of 10-15 mm. If you plan to install the structure on the street, then 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 contour.

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

Decimeter 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 a schematic diagram of a device that can be used with almost any antenna.

Rice. 2. Antenna amplifier circuit for the UHF range

Item List:

• 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 with copper wire Ø 0.8 mm (2.5 turns must be made); L2 and L3 are 25 µH and 100 µH high frequency chokes, 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 coefficients - 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 way the power is supplied, 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 perfect for the arms of a UHF 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, not aluminum, you can solder the cable, and not use self-tapping screws).
• B - places for fastening the shielding braid of the cable.
• C - central vein.
• D - the 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 the 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 quality of the "picture", provided that the signal strength is sufficient.

Making a copper wire antenna

There is a design that is much simpler than the previous version, which requires only a piece of copper wire. This is a narrow band loop antenna. This solution has undeniable 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, it is necessary to calculate the length of the loop, to do this, you need to find out the frequency of the “numbers” for your region. For example, in St. Petersburg it is broadcast on 586 and 666 MHz. The calculation formula will be: 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 Peter 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 that the length of the loop should be 48 centimeters.

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

Now we will tell you how the structure is assembled:

• A piece of copper wire (or RG6 cable) is measured and cut off with a length equal to L R .
• A loop of a suitable diameter is folded, after which a cable is soldered to its ends, which goes to the receiver. If RG6 is used instead of copper wire, then the insulation is first removed from its ends, by about 1-1.5 cm (the central core does not need to be cleaned, it does not participate 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 "numbers", provided that the calculations are carried out correctly.

Do-it-yourself indoor antenna MV and UHF

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

To amplify the signal in this design, a ready-made SWA 9 block is used, if there are problems with its acquisition, you can use a home-made device, the circuit of which was given above (see Fig. 2).

It is important to observe 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, nevertheless, it shows good results if the signal is of sufficient power.

Do-it-yourself figure-eight antenna for digital TV

Consider another common design option for receiving "numbers". It is based on the classic scheme for the UHF range, which, due to its shape, was called the "Eight" or "Zigzag".

Rice. 6. Sketch and implementation of the digital eight

Construction dimensions:

• the outer sides of the rhombus (A) - 140 mm;
• inner sides (B) - 130 mm;
• distance to the reflector (C) - from 110 to 130 mm;
• width (D) - 300 mm;
• step between the bars (E) - from 8 to 25 mm.

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

Homemade antenna for DBT T2

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

As a material, you can use plates made of copper, brass, aluminum or duralumin. If the structure is planned to be installed on the street, then the last two options are not suitable.

Outcome: which option to stop?

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

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

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

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

Today, almost all homes are connected to cable or satellite TV, and almost all channels are of good quality. But what if you just rent an apartment? Here a homemade antenna for digital television will come to the rescue - as a reliable and inexpensive alternative to the factory one. How it is done, read on.

To make this device, you will have to use plywood 550 by 70 mm, several self-tapping screws, and a forty-centimeter copper wire 40 cm long (the central core is 4 mm in diameter).

The basis of the product is a board. Next, cut 8 pieces of wire, the length of which is 375 mm, while they should be stripped in the center by 20-30 mm. This is necessary to ensure good contact in signal transmission.

Now, cut out 2 wires, the length of which is 220 mm and, based on the size of the plank, they should be stripped where the connections will be. After that, the remaining wires (eight pieces) must be bent so that they acquire a “V” shape.

An antenna for digital television is absolutely no different from a conventional decimeter antenna.

First, you should start buying a special plug, after which the antenna and cable should be connected to it. This is easy enough. With a desktop soldering iron, the plug is attached to the wire. This cable is installed over the bottom connection of the instrument. At this stage, the production of the antenna can be considered completed. She's ready to be turned on.

an antenna for digital television is absolutely no different from a conventional decimeter one.

The second method of making a digital television antenna from cans

Here, we will not use the finished device as a basis. The device will be completely assembled from improvised means. A homemade antenna for digital television is made using:

• wooden trempel;
• adhesive tape or electrical tape;
• soldering iron;
• two tin cans;
• several meters of wire (about 3-5 m);
• plugs.

First, you need to finalize the standard television cable. To do this, you need to slightly incise its soft shell. Under the shell, you will see a silvery "foil". This material covers the cable with several layers. For this reason, in order to see the wire itself, you will need to cut off about 10 cm from the edge. After that, the foil layer should be twisted in order to make a cut of its middle layer by about 10 mm. The reverse end of the cord is equipped with a plug used to connect to a TV.

Finished with the cable, banks are next in line. If we talk about dimensions, then a tin container with a volume of 750-1000 mm is enough to receive a digital signal. The end of the wire that is with the “foil” is attached to one bank (otherwise, the channel display will be incorrect). The core of the cable is screwed onto the second can. It is preferable to connect the cable and cans by soldering. If the wire is fixed with adhesive tape, most likely the product will not work.

The only use case for this material is when cans are placed on top of the trempel. However, even here it is impossible to deviate from the technology of application. Namely, the location of the cans should form a straight line. Tin containers should be located at a distance of about 7-8 cm from one another.

That's all, a homemade antenna for digital television is ready. Now you can start searching for a suitable signal and fixing your device. Such an antenna will allow you to view several channels, up to 10-15, if the signal is not password protected.

Video: homemade antenna for digital television

It has always been difficult to get high-quality antennas - the Soviet industry practically did not produce them, so people themselves made them from improvised means. Today, the situation has not changed much - in stores you can only find lightweight aluminum Chinese crafts that do not show good results and rarely live more than a year. What to do if you like to watch TV, but there is no quality reception? The answer is simple -With free time and a pair of skillful hands, anyone can handle this.

Most recently, analog television operated in Russia, but now almost the entire country has switched to digital broadcasting. Its main difference is that it works in the decimeter range.

You can create a homemade antenna for the digital range at home

This was done for reasons of economy and safety - care for transmitting antenna-feeder stations is actually not required, their maintenance is minimized, and harm from contact with powerful transmitters for masters is minimal. But such stations have one serious drawback - low power. And if in a big city the signal can often be caught even on a piece of copper wire, then far from the transmitter, reception can be difficult. If you live outside the city, in remote areas or villages, you will have to assemble your own antenna and take it outside to catch the desired signal.

Attention:signal problems can occur even in the city center. Decimeter waves are practically not muffled by other sources, but are reflected from thick reinforced concrete walls. In modern high-rise buildings there are many places where they are completely attenuated, not reaching the TV receiver.

It is also worth noting that DVB-T2 (the new television standard) offers a fairly constant but weak signal. With a noise level one and a half to two units above the norm, the TV reproduces the air quite clearly, but as soon as the noise exceeds 2 dB, the signal disappears completely. Digital television is not sensitive to electromagnetic interference - it is not knocked down by a working refrigerator or microwave. But if there is a mismatch anywhere in the system, then the picture stops or falls apart. qualitysolve this problem, but in some cases, it will have to be taken out onto the street or onto the roof.

Basic requirements for antennas

The television standards in force in the USSR do not fit modern realities - the protective and directional coefficients today have practically no effect on signals. The air in the cities is clogged and contains a lot of dirt, so you should not pay attention to these coefficients. You are guaranteed to receive interference on any antenna, so you do not need to achieve a reduction in DRR AND NPV. It is better to improve the gain of the antenna so that it receives a large range of air and selects the desired stream, rather than focusing on a specific signal. The processor of the set-top box or TV itself will isolate the necessary signals and create a normal picture.

Classic Polish antenna with amplifier

So, Experienced engineers recommend building band antennas. They must be correctly calculated by taking signals in the classical way, and not by engineering "optimizations" and traps. The ideal option is that the device fully complies with theoretical calculations and geometry. Also, the constructed antenna must be consistent with the cable at operating ranges without the use of matching devices. In this case, it is best to create a frequency response smooth and even, since phase distortions appear when the amplitude-frequency characteristic fails or jumps.

Attention: analog antennas with ferrite USS, which provide full-fledged reception of the old signal, practically do not work with DVB. It is necessary to build a “digital” antenna.

In the article we will analyze modern types of antennas that work with new digital broadcasting.

Antenna types

What do-it-yourself digital TV antennas can be collected at home? There are three most common options:

1. All-wave, or as radio amateurs call it, is frequency independent. It assembles very quickly, does not require high knowledge or specialized tools. Well suited for the private sector, villages, summer cottages - where the air is not littered with garbage, but not far from the transmitter.
2. log-periodic range. It has a simple design, well receives a signal at a close and medium distance from the transmitter. It can be used as a remote if the transmitter is located far away, or as a home wall antenna.
3. Z-antenna and its variations. Many radio amateurs are familiar with meter-long "zashkas" - they are quite large and require a lot of effort to assemble. But in the decimeter range, they are quite compact and do their job well.

The nuances of construction

If you want to build a quality antenna, you must master the art of soldering. You can not twist the contacts and guides - during operation they are oxidized, the signal is lost, the picture quality deteriorates. Therefore, all connections are soldered.

Such connections are not allowed - be sure to solder them

You also need to deal with zero-potential points where currents occur even when there is no voltage. Experts recommend making them from a single piece of metal, without using welding at all. Even high-quality welded pieces can make noise at the boundary values, while a solid strip will “pull out” the signal.

Also when creating homemade antenna for digital TV you need to deal with soldering cables. Today, copper is practically not used for braiding, since it is expensive and quickly oxidizes. Modern braid is made of steel, which is not afraid of corrosion, but it is very poorly soldered. It must not be overheated or squeezed. Use 36-40 watt soldering irons, flux and light solder to connect. Dip the winding well in the flux and apply solder - it is perfectly taken with this method of application.

All Wave Antenna

The all-wave antenna has a fairly simple design. It consists of triangles, copper wire and wooden slats. You can study the design in more detail in the picture - it does not represent something supernatural.

The thickness of the wire can be any, the distance between adjacent wires is 25-30 mm, the distance between the plates is no more than 10 mm. The design can be improved by abandoning the plates and using textolite. It needs to be given the appropriate shape or just remove the copper foil in the shape of a triangle.

The remaining proportions are standard - the height of the device must match the width, the plates diverge at a right angle. Zero potential is on the extreme line home tv antenna , just at the intersection of the cable with the vertical guide. To avoid quality losses, the cable must be pulled to it with a tie - this is enough for coordination. Such an antenna, hung out on the street or directed at a window, receives virtually the entire frequency range, but has a small dip, so you need to set the correct angle when fixing the antenna.

By the way, this design can be upgraded with ordinary aluminum cans from beer and cola. The principle of its operation is as follows: with an increase in the span of the shoulders, the working band expands, although the rest of the indicators remain within the original limits. The Nadenenko dipole, often used in military developments, works on the same principle. Aluminum cans fit perfectly in shape and size, creating vibrator arms in the decimeter range.

Double Can Antenna for TV

You can create a simple canned antenna by simply soldering two cans to a cable. This do-it-yourself indoor TV antenna suitable for viewing channels at a small to medium distance from transmitters. Nothing needs to be coordinated in this scheme, especially if the cable length is less than 2 meters.

You can complicate the design by assembling a full-fledged lattice from eight cans and using an amplifier from an ordinary Polish antenna. This design is great for hanging outdoors in areas remote from the transmitter. To enhance the signal, a metal mesh can be placed behind the structure.

Z antenna

There are complex Z-antenna designs with multiple loops, but in most cases they are not needed. You can easily assemble a structure from ordinary copper wire 3 mm thick. If you don’t have one, then just buy a single-core copper wire 3 mm long, 120 mm long - this will be enough for you to work. This design consists of two segments. We bend the wire according to the following scheme:

1. The starting section is 14 centimeters long. Its edge is bent into a loop to connect with the last one (loop 1 cm, total length of the first piece - 13 cm).
2. The second piece is bent at 90 degrees (it is better to bend with pliers to keep the angles). Its length is 14 cm.
3. The third piece is bent at 90 degrees parallel to the first, length 14 cm.
4. The fourth and fifth pieces are 13 cm each, the bend does not reach the loop by 2 cm.
5. The sixth and seventh pieces are 14 cm each, bent at 90 degrees.
6. Eighth - returns to the loop, length 14.1 cm goes to a new loop.

Next, you need to clean the two loops well and solder them. The opposite corner is also cleared. The cable contacts are soldered to them - to one central, to the second - a braid. There is no difference to which contact to solder.. It is advisable to insulate the soldered places, for this you can use sealants or hot melt adhesive. The ends of the cable are soldered to the plug and also insulated with cambric.

You can assemble such an antenna in half an hour

To avoid displacement of the segments, the edges can be reinforced. To do this, take an ordinary plastic cap from a five-liter bottle, cut 4 slots in it so that the wire sinks to the base. Cut the fifth hole for the cable. Then put the antenna into the cover (after checking the quality and reliability of the soldering), and fill it with hot glue. The resulting design will be practically eternal - it is capable of receiving a stable signal at a distance of up to 10 km from the source.

So you already know what can be used instead of a TV antenna. In fact, the designs are much larger than those that we have described, but even these will be enough for you. If you live far from the signal source, then you will need amplifying antennas - you can get by with the classic “polka” with gain. Well, if everything is bad with the ether, then use satellites.

The era of digital signals has arrived. All broadcasting TV companies began to work in a new format. Analog TVs are dying out. They are still in working condition and are available in almost every family.

In order for the old models to successfully finalize their resource, and for people to use them when watching digital broadcasting, it is enough to connect the DVB-T set-top box to the TV receiver and pick up TV wave signals with a special antenna.

Any home master is able not to buy an antenna in a store, but to make it with his own hands from improvised means for watching digital TV programs at home or in the country. The two most accessible designs are described in this article.

A bit of theory

The principle of operation of the antenna for digital packet television

Any television signal propagates in space from the emitters of the transmitting TV tower to the TV antenna as an electromagnetic wave of a sinusoidal shape with a high frequency, measured in megahertz.

When an electromagnetic wave passes through the surface of the receiving beams of the antenna, a voltage V is induced in it. Each half-wave of the sinusoid forms a potential difference with its own sign.

Under the action of an induced voltage applied to a closed receiving circuit of the input signal with resistance R, an electric current flows in the latter. It is amplified and processed by the digital TV circuitry and output to the screen and speakers as picture and sound quality.

For analog models of TV receivers, an intermediate link works between the antenna and the TV - the DVB-T prefix, which decodes the digital information of the electromagnetic wave into a normal form.

Vertical and horizontal polarization of digital TV signal

In television broadcasting, state standards adopted electromagnetic waves to radiate in only two planes:

1. horizontal.

In this way, the transmitters direct the radiating signals.

And users simply need to rotate the receiving antenna in the desired plane to maximize the power potential removal.

Requirements for a digital packet television antenna

TV transmitters propagate their signal-waves over short distances, limited by a line-of-sight zone from the top point of the TV tower emitter. Their range rarely exceeds 60 km.

For such distances, it is sufficient to ensure the power of the emitted TV signal of a small value. But, the intensity of the electromagnetic wave at the end of the coverage area should form a normal voltage level at the receiving end.

A small potential difference, measured in fractions of a volt, is induced on the antenna. It creates currents with small amplitudes. This imposes high technical requirements for the installation and workmanship of all parts of digital reception devices.

The design of the antenna must be:

• made carefully, with a good degree of accuracy, eliminating the loss of electrical signal power;
• directed strictly along the axis of the electromagnetic wave coming from the transmitting center;
• oriented according to the type of polarization;
• protected from extraneous interference signals of the same frequency coming from any sources: generators, radio transmitters, electric motors and other similar devices.

How to find out the initial data for calculating the antenna

The main parameter affecting the quality of the received digital signal, as can be seen from the explanatory first figure, is the length of the electromagnetic radiation wave. Under it, symmetrical arms of vibrators of various shapes are created, and the overall dimensions of the antenna are determined.

The wavelength λ in centimeters can be easily calculated using a simplified formula: λ=300/F. It is enough just to find the frequency of the received signal F in megahertz.

For this, we will use the Google search and ask it for a list of regional TV communication points for our area.

As an example, a fragment of the data table for the Vitebsk region is shown with a red rectangle highlighting the transmitting center in Ushachi.

The frequency of its wave is 626 megahertz, and the type of polarization is horizontal. These data are sufficient.

We perform the calculation: 300/626 \u003d 0.48 m. This is the length of the electromagnetic wave for the antenna being created.

We divide it in half and get 24 cm - the desired half-wave length.

The tension reaches its maximum value in the middle of this section - 12 cm. It is also called amplitude. Under this size, a whip antenna is made. It is usually expressed by the formula λ/4, where λ is the length of the electromagnetic wave.

The simplest TV antenna for digital television

It will require a piece of coaxial cable with a characteristic impedance of 75 ohms and a plug to connect the antenna. I managed to find a ready-made two-meter piece in an old stock.

From the free end with an ordinary knife, I cut off the outer shell. I take the length with a small margin: when adjusting, it is always easier to bite off a small segment.

Then I remove the shielding layer from this section of the cable.

The work is done. It remains to insert the plug socket into the connector on the TV signal set-top box and direct the bare wire of the inner core across the incoming electromagnetic wave, taking into account horizontal polarization.

The antenna should be placed directly on the windowsill or fixed on the glass, for example, with a piece of adhesive tape or tied to the blinds. Reflected signals and interference can be shielded with a strip of foil located at a small distance from the central core.

Such a design is done literally in ten minutes and does not require special material costs. It's worth trying it out. But, it is able to work in the zone of reliable signal reception. My building is screened by a mountain and a multi-storey building. The transmitting TV tower is located at a distance of 25 km. Under these conditions, the digital electromagnetic wave is reflected many times and is poorly received. I had to look for another technical solution.

And for you, on the topic of this design, I suggest watching the video of the owner Edokoff “How to make an antenna for digital TV”

Antenna Kharchenko at 626 MHz

To receive analog broadcasting signals of various wave frequency ranges, the design of a zigzag broadband antenna, which does not require complex manufacturing, worked well for me before.

I immediately remembered one of their effective varieties - the Kharchenko antenna. I decided to use its design for digital reception. The vibrators were made from a flat copper bar, but it is quite possible to get by with a round wire. This will make it easier to bend and align the ends.

How to determine the dimensions of a particular antenna

Online calculator

Let's use the all-knowing Google search. We write on the command line: "Calculation of the Kharchenko antenna" and press Enter.

Choose any site you like and perform an online calculation. I went to the first one that opened. Here's what he gave me.

I presented all his data with a picture with the designation of the name of the size of the Kharchenko antenna.

Manufacture of antenna design details

I took the information provided as a basis, but did not accurately withstand all dimensions. I know from previous practice that the antenna works well in the broadband wave range. Therefore, the dimensions of the parts are just slightly overestimated. The half-wave of each harmonic of the sinusoid of the electromagnetic TV signal will fit into the shoulder of each vibrator and will be accepted by it.

Based on the selected data, I made blanks for the antenna.

Vibrator Design Features

The connection of the ends of the shank for the "eight" was created in the center at the bending stage. Soldered them with a soldering iron.

It was created for me according to the “Moment” principle, made with my own hands from old transformers, it has been working for two decades. I even soldered a copper wire of 2.5 squares to them in a thirty-degree frost. Works with transistors and microcircuits without burning them.

I plan to describe its design in the near future in a separate article on the site for those who also want to make it with their own hands. Follow the publications, subscribe to notifications.

Connecting the Antenna Cable to the Vibrator

I simply soldered the copper core and braid to the figure-eight metal from different sides in its center.

The cable was tied to a copper bar, bending it with a loop in the shape of a semi-square vibrator. In this way, the resistance of the cable and antenna is matched.

Shielding grid design

In fact, the Kharchenko antenna often works fine without signal shielding, but I decided to show its manufacture. For the base, I took a wooden block. I did not paint and impregnate with varnish: the structure will be used indoors.

I drilled holes in the back side of the bar for attaching the screen wires and inserted them, and then wedged them.

The result was a screen for Kharchenko's antenna. In principle, it can also be made of a different design: cut out of a piece of the frontal armor of a tank or cut out of food foil - it will work in about the same way.

On the reverse side of the bar, I fixed the design of the vibrator with the cable.

The antenna is ready. It remains to install it on the window to work in vertical polarization.

When a television receiver is at a great distance from the transmitting generator, then the power of its signal gradually weakens. It can be increased by special electronic devices - amplifiers.

You just need to clearly see the difference between the signals received by the antenna, which can be:

1. just weakened;
2. contain high-frequency interference that distorts the shape of a digital sinusoid to the shape of some kind of "karyabola".

In both cases, the amplifier will fulfill its role and raise the power. Moreover, the TV will clearly perceive and show a weakened signal, and with an enhanced “karyabola”, playback problems will arise.

To eliminate such wave interference are called upon:

• h/h filters;
• screens.

They must be measured with an oscilloscope, and the ways of using various designs should be analyzed in each specific case individually. The antenna is not to blame.

In the days of huge tube TVs, a good antenna for high-quality analog TV reception was in short supply. Those that could be bought in stores were not of high quality. Therefore, people made UHF television antennas with their own hands. Today, many are interested in homemade devices. And even when digital technologies are everywhere, this interest does not fade away.

Digital era

This era also affected television. Today, T2 broadcasting is developing especially widely. It has its own characteristics. In those places where the signal level slightly exceeds the interference, a fairly high-quality reception is obtained. There is simply no further signal. The digital signal does not care about interference, however, in a situation of cable mismatch or various phase distortions, almost anywhere in the transmitting or receiving path, the picture can go in squares even with a strong signal level.

In modern television, other changes have taken place. So, all broadcasting is carried out in the UHF band, the transmitters have good coverage. The conditions under which radio waves propagate through cities have changed dramatically.

Antenna parameters

Before you start manufacturing, you need to determine some parameters of these structures. They, of course, require in-depth knowledge in various areas of mathematics, as well as the laws of electrodynamics.

So, the gain is the ratio of the power at the input of the reference system to the power at the input of the antenna used. All this will work if each of the antennas creates the values ​​of the intensity and flux density with the same parameters. The value of this coefficient is dimensionless.

The directional factor is the ratio of the field strength that the antenna produces to the field strength in any direction.

It must be remembered that parameters such as KU and KND are not interconnected. There is a UHF antenna for digital TV, which has a very high directivity. However, its enhancement is small. These designs are directed into the distance. There are also designs with high directivity. Here it comes in combination with a very powerful level of amplification.

Today, you can not look for formulas, but use special programs. They already take into account all the necessary parameters. You just have to enter some conditions - and you will receive a complete calculation of the UHF antenna, so that you can then assemble it.

Manufacturing nuances

Any structural element in which signal currents flow must be connected using a soldering iron or a welding machine. Such a node, if it is in the open air, suffers from a breakdown in contact. From this, various antenna parameters and the reception level can become significantly worse.

This is especially true for points with zero potentials. According to experts, voltage can be observed in them, as well as current antinode. To be more precise, this is the maximum current value. Is it available at zero voltages? No wonder.

Such places are best made from solid metal. Creeping currents are unlikely to affect the picture if the connections are made by welding. However, due to their presence, the signal may disappear.

How and what to solder?

Do-it-yourself UHF antenna is not very easy to make. This involves working with a soldering iron. Modern television cable manufacturers no longer make it copper. Now there is an inexpensive alloy that is resistant to corrosion. These materials are difficult to solder. And if they are heated long enough, there is a risk of burning the cable.

Experts recommend using low-power soldering irons, low-melting solders, and fluxes. Do not spare the paste when soldering. The solder will lie correctly only if it is under a layer of boiled flux.

Catch T2

In order to enjoy digital TV, it is enough to purchase a special tuner. But it does not have a built-in antenna. And those that are offered as special digital ones are too expensive and meaningless.

Now we will learn how to catch T2 on a completely homemade design. Homemade UHF antenna - it's simple, cheap, high quality. Try it yourself.

The simplest antenna

To assemble this design, you will not even need to go to the store. For its manufacture, a conventional antenna cable is sufficient. You need 530 mm of wire for the ring and 175 mm from which the loop will be made.

The TV antenna itself is a ring of cable. The ends must be stripped, and then connected to the loop. And to the latter you need to solder a cable that connects to the T2 tuner. So, on the ring, the screen and the central core are connected to the screens of the loop. At the last, the central veins are also connected. And the cable to the tuner is soldered as standard to the screen and the central core.

So we got the UHF antenna, made with our own hands. Its construction turned out to be very cheap and practical. And it works no worse than expensive store options. It must be fixed on plywood or plexiglass. For this, construction clamps are perfect.

"People's" antenna

This design is an aluminum disc. The outer diameter of the element should be 365 mm and the inner diameter 170 mm. The disc must be 1 mm thick. First you need to make a cut in the disk (10 mm wide). In the place where he drank, you should install a printed circuit board made of textolite. It should be 1 mm thick.

The board must have holes for the M3 screws. The board must be glued to the disk. Then you need to solder the cable leads to it. The central core should be soldered to one side of the disk, the screen to the other. In terms of quality, such a TV antenna will receive better with two discs, especially if it is far from the TV repeater.

Universal Antenna

Nothing supernatural will be used to make this design. We will make it from various improvised materials. However, although it is homemade, it will work perfectly in the entire decimeter range. So, this UHF antenna, quickly made with your own hands, is in no way inferior to store-bought, more expensive designs. To receive T2, it will be enough completely.

So, to assemble this design, you will need empty cans of canned food or beer. You need 2 cans with a diameter of 7.5 cm. The length of each is 9.5 cm. You also need to stock up on strips of textolite or getinax, always with foil.

Our cans need to be connected to the textolite strips using a soldering iron. The plate of this material, which will connect the containers at the top, must be completely covered with copper foil. On the bottom plate, the foil should be cut. This is done for easy cable connection.

It is necessary to assemble the structure in such a way that the total length is not less than 25 cm. This antenna (UHF band) is a broadband symmetrical vibrator. Due to its surface area, it has large gains.

If suddenly you cannot find suitable jars, then you can use containers with a smaller diameter. However, then the foil will have to be cut on the upper connecting plate as well.

"Beer" antenna

Love to drink beer? Don't throw away cans. You can make a good antenna out of them. To do this, you need to fix two beer cans on any dielectric material.

First you need to choose the right cable, and then bring it to mind. To do this, the cable must be stripped. You will see shielding foil. There will be a protective layer underneath. But under it, you can directly observe the cable.

For our antenna, you need to strip the top layer of this wire by about 10 cm. The foil must be carefully twisted to end up with a branch. The protective layer for the central core must be cleaned by 1 cm.

On the other hand, you need to solder the plug for the TV to the cable. If you were a subscriber of cable networks, then this part and cable will not even have to be purchased separately.

Now for the cans. It is advisable to use beer containers with a volume of 1 liter. However, good German beer in such cans is expensive, and domestic beer is not sold.

Banks must be opened very carefully. Then you need to free the container from the contents, and then dry it well. Next, use a self-tapping screw to connect our screen on the cable and the jar. To the second you need to fasten the central core.

For a better image quality, it is better to connect the containers and the cable with a soldering iron.

It is necessary to fix the banks on some dielectric material. It should be noted that they should be located on the same straight line. The distance between them depends on the capacity. All this is selected only by experience.

Zigzag

The UHF zigzag antenna has the simplest possible design. The item itself is broadband. Its device allows you to allow various deviations from the original design parameters. At the same time, its electrical parameters are almost not violated.

Its input resistance in a certain range depends on the size of the conductors that will form the basis of the web. There is a dependency here. The greater the width or thickness of the conductors, the better the antenna will be matched to the feeder. In general, any conductors can be used to make a web. For this, plates, and tubes, and corners, and much more are suitable.

In order to increase the directivity of such an antenna, it is permissible to use a flat screen, which will play the role of a reflector. The latter will reflect high-frequency energy towards the antenna. Such screens are often large, and the phase depends mainly on the distance.

On the practical side, the reflector is only rarely made from a single sheet of metal. More often it is made in the form of conductors that are connected in the same plane. For design reasons, it is not necessary to make a screen that is too dense. The conductors from which the screen itself will be made are attached by welding or soldering to a metal frame.

This design is made very simply. It works well in the UHF range. In the USSR, it was a real folk irreplaceable model. It has a small size, so it can be used as a UHF indoor antenna.

The material will be copper tubes or aluminum sheet. The side parts can be made of solid metal. Often they are tightened with a net or covered with a tin. If one of the indicated methods is used, then the structure should be soldered along the contour.

The cable must not be bent sharply. How to carry out this element, you can see in the pictures presented.

It must be guided in such a way that it reaches the side corner, but does not go beyond the antenna or side square.

Indoor antenna MV UHF

This design is designed for easy and reliable reception of digital television signals. It can be made easily and very quickly. To do this, you need an aluminum or copper bar. Its length should be up to 1800 mm. This antenna can also be used as an outdoor antenna.

The design is a frame in the form of a rhombus. There should be two. One acts as a vibrator, the second works as a reflector. To receive T2, it is necessary that the side of our rhombus is approximately 140 mm, and the distance between them is 100 mm.

After the frame is made and the structure becomes rigid, a dielectric is mounted between the two ends of our rod. It could be anything. Shape and size are completely irrelevant. The distance between two points of the bars should be approximately 20 mm. The upper parts of our rhombuses need to be connected.

The feeder can be made from a cable. It must be connected to brass or copper petals, which should already be fixed on the antenna output.

If the resulting design does not meet your expectations, for example, poor reception quality or the repeater is far away, you can supply the antenna with an amplifier - and as a result you will get an active UHF antenna. It is used both in the city and in the country.

The simplest UHF loop antenna

This design resembles the number "zero". By the way, this is the coefficient of its amplification. It is ideal for T2 reception. This part is able to work better than the products that are offered in stores.

It is also called digital, because with it you can perfectly catch digital broadcasts. It is narrowband, and this is a significant advantage. It works on the principle of a selective valve, which allows us to talk about reliable protection against interference.

For assembly, you will need an ordinary coaxial cable with a resistance of 75 ohms, as well as a regular TV plug. It is better to choose a cable with a large diameter of all options. As a stand, you can use a cardboard box or something else.

How long the frame will be, we determine using programs for calculating antenna parameters. The material for the manufacture of the frame can be used the same as in the cable. By the way, for calculations you need to know the frequencies of digital broadcasting in your city.

The central core of the cable in the frame design is not needed. The stripped wire is twisted together with the core and braid of the frame. Then this connection must be soldered.

The structure must be placed on a dielectric base. Better to keep it away from your tuner. It is important that there is no voltage at the antenna input.

So, we found out how the UHF antenna is made with our own hands. As you can see, this is not such a difficult task. But now you can watch your favorite TV shows in digital quality. And such a design is installed in the same way as a regular store - on the roof. You can use screws or bolted connection. It should be installed in a safe place so that during gusts of wind it does not fly off along with a piece of slate. It is desirable that the antenna is mounted at the highest possible height. Thus, you will exclude the appearance of interference during the display of cable or digital television.