Drawing of a decimeter antenna for digital TV. Antenna for T2 - DIY - Various equipment - - Radio circuits, magazines, repairs, modding

Once upon a time, a good television antenna was in short supply; purchased ones did not differ in quality and durability, to put it mildly. Making an antenna for a “box” or “coffin” (an old tube TV) with your own hands was considered a sign of skill. Interest in homemade antennas continues to this day. There is nothing strange here: the conditions for TV reception have changed dramatically, and manufacturers, believing that there is and will not be anything significantly new in the theory of antennas, most often adapt electronics to long-known designs, without thinking about the fact that The main thing for any antenna is its interaction with the signal on the air.

What has changed on air?

Firstly, almost the entire volume of TV broadcasting is currently carried out in the UHF range. First of all, for economic reasons, it greatly simplifies and reduces the cost of the antenna-feeder system of transmitting stations, and, more importantly, the need for its regular maintenance by highly qualified specialists engaged in hard, harmful and dangerous work.

Second - TV transmitters now cover almost all more or less populated areas with their signal, and a developed communication network ensures the delivery of programs to the most remote corners. There, broadcasting in the habitable zone is provided by low-power, unattended transmitters.

Third, the conditions for the propagation of radio waves in cities have changed. On the UHF, industrial interference penetrates weakly, but reinforced concrete high-rise buildings are good mirrors for them, repeatedly reflecting the signal until it is completely attenuated in an area of ​​seemingly reliable reception.

Fourth - There are a lot of TV programs on air now, dozens and hundreds. How diverse and meaningful this set is is another question, but counting on receiving 1-2-3 channels is now pointless.

Finally, developed digital broadcasting . The DVB T2 signal is a special thing. Where it still exceeds the noise even just a little, by 1.5-2 dB, the reception is excellent, as if nothing had happened. But a little further or to the side - no, it’s cut off. Digital is almost insensitive to interference, but if there is a mismatch with the cable or phase distortion anywhere in the path, from the camera to the tuner, the picture can crumble into squares even with a strong clean signal.

Antenna requirements

In accordance with the new reception conditions, the basic requirements for TV antennas have also changed:

• Its parameters such as the directional coefficient of action (DC) and the coefficient of protective action (CPA) are now of no decisive importance: modern ether is very dirty, and side lobe directional pattern (DP), at least some kind of interference will get through, and you need to fight it using electronic means.
• In return, the antenna's own gain (GA) becomes especially important. An antenna that “catches” the air well, rather than looking at it through a small hole, will provide a reserve of power for the received signal, allowing the electronics to clear it of noise and interference.
• A modern television antenna, with rare exceptions, must be a range antenna, i.e. its electrical parameters must be preserved naturally, at the level of theory, and not squeezed into acceptable limits through engineering tricks.
• The TV antenna must be coordinated with the cable over its entire operating frequency range without additional devices coordination and balancing (USS).
• The amplitude-frequency response of the antenna (AFC) should be as smooth as possible. Sharp surges and dips are certainly accompanied by phase distortions.

The last 3 points are determined by the requirements for receiving digital signals. Customized, i.e. Working theoretically at the same frequency, antennas can be “stretched” in frequency, for example. antennas of the “wave channel” type on the UHF with an acceptable signal-to-noise ratio capture channels 21-40. But matching them with the feeder requires the use of USSs, which either strongly absorb the signal (ferrite) or spoil the phase response at the edges of the range (tuned). And such an antenna, which works perfectly on analogue, will receive “digital” poorly.

In this regard, from all the great variety of antennas, this article will consider TV antennas, available for self-production, of the following types:

1. Frequency independent (all-wave)– does not have high parameters, but is very simple and cheap, it can be done in literally an hour. Outside the city, where the airwaves are cleaner, it will be able to receive digital or a fairly powerful analogue, no great distance from the television center.
2. Range log-periodic. Figuratively speaking, it can be likened to a fishing trawl, which sorts the prey during fishing. It is also quite simple, fits perfectly with the feeder throughout its entire range, and does not change its parameters at all. Technical parameters are average, so it is more suitable for a summer residence, and in the city as a room.
3. Several modifications zigzag antenna , or Z-antennas. In the MV range, this is a very solid design that requires considerable skill and time. But on the UHF, due to the principle of geometric similarity (see below), it is so simplified and shrunk that it can well be used as a highly effective indoor antenna under almost any reception conditions.

Note: The Z-antenna, to use the previous analogy, is a frequent dragster that scoops up everything in the water. As the air became littered, it fell out of use, but with the development of digital TV, it was once again on the high horse - throughout its entire range, it is just as perfectly coordinated and keeps the parameters as a “speech therapist.”

Precise matching and balancing of almost all antennas described below is achieved by laying the cable through the so-called. zero potential point. It has special requirements, which will be discussed in more detail below.

About vibrator antennas

In the frequency band of one analog channel, up to several dozen digital ones can be transmitted. And, as already said, the digital works with an insignificant signal-to-noise ratio. Therefore, in places very remote from the television center, where the signal of one or two channels barely reaches, the good old wave channel (AVK, wave channel antenna), from the class of vibrator antennas, can be used for receiving digital TV, so at the end we will devote a few lines and to her.

About satellite reception

There is no point in making a satellite dish yourself. You still need to buy a head and a tuner, and behind the external simplicity of the mirror lies a parabolic surface of oblique incidence, which not everyone can perform with the required accuracy. industrial enterprise. The only thing homemade people can do is set up a satellite dish, about that.

About antenna parameters

Accurate determination of the antenna parameters mentioned above requires knowledge of higher mathematics and electrodynamics, but it is necessary to understand their meaning when starting to manufacture an antenna. Therefore, we will give somewhat rough, but still clarifying definitions (see figure on the right):

• KU is the ratio of the signal power received by the antenna on the main (main) lobe of its DP to its same power received in the same place and at the same frequency by an omnidirectional, circular, DP antenna.
• KND is the ratio of the solid angle of the entire sphere to the solid angle of the opening of the main lobe of the DN, assuming that its cross section is a circle. If the main petal has different sizes in different planes, you need to compare the area of ​​the sphere and its cross-sectional area of ​​the main petal.
• SCR is the ratio of the signal power received at the main lobe to the sum of the interference powers at the same frequency received by all secondary (back and side) lobes.

Notes:

1. If the antenna is a band antenna, the powers are calculated at the frequency of the useful signal.
2. Since there are no completely omnidirectional antennas, a half-wave linear dipole oriented in the direction of the electric field vector (according to its polarization) is taken as such. Its QU is considered equal to 1. TV programs are transmitted with horizontal polarization.

It should be remembered that CG and KNI are not necessarily interrelated. There are antennas (for example, “spy” - single-wire traveling wave antenna, ABC) with high directivity, but single or lower gain. These look into the distance as if through a diopter sight. On the other hand, there are antennas, e.g. Z-antenna, which combines low directivity with significant gain.

About the intricacies of manufacturing

All antenna elements through which useful signal currents flow (specifically, in the descriptions of individual antennas) must be connected to each other by soldering or welding. In any prefabricated unit in the open air, the electrical contact will soon be broken, and the parameters of the antenna will deteriorate sharply, up to its complete unusability.

This is especially true for points of zero potential. In them, as experts say, there is a voltage node and a current antinode, i.e. its greatest value. Current at zero voltage? Nothing surprising. Electrodynamics has moved as far from Ohm's law on direct current as the T-50 has gone from a kite.

Places with zero potential points for digital antennas are best made bent from solid metal. A small “creeping” current in welding when receiving the analogue in the picture will most likely not affect it. But, if a digital signal is received at the noise level, then the tuner may not see the signal due to the “creep”. Which, with pure current at the antinode, would give stable reception.

About cable soldering

The braid (and often the central core) of modern coaxial cables is made not of copper, but of corrosion-resistant and inexpensive alloys. They solder poorly and if you heat them for a long time, you can burn out the cable. Therefore, you need to solder the cables with a 40-W soldering iron, low-melting solder and with flux paste instead of rosin or alcohol rosin. There is no need to spare the paste; the solder immediately spreads along the veins of the braid only under a layer of boiling flux.

Types of antennas

All-wave

An all-wave (more precisely, frequency-independent, FNA) antenna is shown in Fig. It consists of two triangular metal plates, two wooden slats, and a lot of enameled copper wires. The diameter of the wire does not matter, and the distance between the ends of the wires on the slats is 20-30 mm. The gap between the plates to which the other ends of the wires are soldered is 10 mm.

Note: Instead of two metal plates, it is better to take a square of one-sided foil fiberglass with triangles cut into copper.

The width of the antenna is equal to its height, the opening angle of the blades is 90 degrees. The cable routing diagram is shown there in Fig. The point marked in yellow is the point of quasi-zero potential. There is no need to solder the cable braid to the fabric in it; just tie it tightly, and the capacity between the braid and the fabric will be enough for matching.

The CHNA, stretched in a window 1.5 m wide, receives all meter and DCM channels from almost all directions, except for a dip of about 15 degrees in the plane of the canvas. This is its advantage in places where it is possible to receive signals from different television centers; it does not need to be rotated. Disadvantages - single gain and zero gain, therefore, in the interference zone and outside the zone of reliable reception, the CNA is not suitable.

Note : There are other types of CNA, for example. in the form of a two-turn logarithmic spiral. It is more compact than the CNA made of triangular sheets in the same frequency range, therefore it is sometimes used in technology. But in everyday life this does not provide any advantages, it is more difficult to make a spiral CNA, and it is more difficult to coordinate with a coaxial cable, so we are not considering it.

Based on the CHNA, the once very popular fan vibrator (horns, flyer, slingshot) was created, see fig. Its directivity factor and coefficient of performance are something around 1.4 with a fairly smooth frequency response and linear phase response, so it would be suitable for digital use even now. But - it works only on HF (channels 1-12), and digital broadcasting is on UHF. However, in the countryside, with an elevation of 10-12 m, it may be suitable for receiving an analogue. Mast 2 can be made of any material, but fastening strips 1 are made of a good non-wetting dielectric: fiberglass or fluoroplastic with a thickness of at least 10 mm.

Beer all-wave

The all-wave antenna made from beer cans is clearly not the fruit of the hangover hallucinations of a drunken radio amateur. It's really very good antenna for all cases of reception, you just need to do it correctly. And it’s extremely simple.

Its design is based on the following phenomenon: if you increase the diameter of the arms of a conventional linear vibrator, then its operating frequency band expands, but other parameters remain unchanged. In long-distance radio communications, since the 20s, the so-called Nadenenko's dipole based on this principle. And beer cans are just the right size to serve as the arms of a vibrator on the UHF. In essence, the CHNA is a dipole, the arms of which expand indefinitely to infinity.

The simplest beer vibrator made of two cans is suitable for indoor analogue reception in the city, even without coordination with the cable, if its length is no more than 2 m, on the left in Fig. And if you assemble a vertical in-phase array from beer dipoles with a step of half a wave (on the right in the figure), match it and balance it using an amplifier from a Polish antenna (we will talk about it later), then thanks to the vertical compression of the main lobe of the pattern, such an antenna will give good CU.

The gain of the “tavern” can be further increased by adding a CPD at the same time, if a mesh screen is placed behind it at a distance equal to half the grid pitch. The beer grill is mounted on a dielectric mast; The mechanical connections between the screen and the mast are also dielectric. The rest is clear from the following. rice.

Note: the optimal number of lattice floors is 3-4. With 2, the gain in gain will be small, and more is difficult to coordinate with the cable.

Video: making a simple antenna from beer cans

"Speech therapist"

A log-periodic antenna (LPA) is a collecting line to which halves of linear dipoles (i.e., pieces of conductor a quarter of the operating wavelength) are alternately connected, the length and distance between which vary in geometric progression with an index less than 1, in the center in Fig. The line can be either configured (with a short circuit at the end opposite to the cable connection) or free. An LPA on a free (unconfigured) line is preferable for digital reception: it comes out longer, but its frequency response and phase response are smooth, and the matching with the cable does not depend on frequency, so we will focus on it.

The LPA can be manufactured for any predetermined frequency range, up to 1-2 GHz. When the operating frequency changes, its active region of 1-5 dipoles moves back and forth along the canvas. Therefore, the closer the progression indicator is to 1, and accordingly the smaller the antenna opening angle, the greater the gain it will give, but at the same time its length increases. At UHF, 26 dB can be achieved from an outdoor LPA, and 12 dB from a room LPA.

LPA can be said to be an ideal digital antenna based on its totality of qualities, so let’s look at its calculation in a little more detail. The main thing you need to know is that an increase in the progression indicator (tau in the figure) gives an increase in gain, and a decrease in the LPA opening angle (alpha) increases the directivity. A screen is not needed for the LPA; it has almost no effect on its parameters.

Calculation of digital LPA has the following features:

1. They start it, for the sake of frequency reserve, with the second longest vibrator.
2. Then, taking the reciprocal of the progression index, the longest dipole is calculated.
3. After the shortest dipole based on the given frequency range, another one is added.

Let's explain with an example. Let's say our digital programs lie in the range of 21-31 TVK, i.e. at 470-558 MHz in frequency; wavelengths, respectively, are 638-537 mm. Let’s also assume that we need to receive a weak noisy signal far from the station, so we take the maximum (0.9) progression rate and the minimum (30 degrees) opening angle. For the calculation you will need half the opening angle, i.e. 15 degrees in our case. The opening can be further reduced, but the length of the antenna will increase exorbitantly, in cotangent terms.

We consider B2 in Fig: 638/2 = 319 mm, and the arms of the dipole will be 160 mm each, you can round up to 1 mm. The calculation will need to be carried out until you get Bn = 537/2 = 269 mm, and then calculate another dipole.

Now we consider A2 as B2/tg15 = 319/0.26795 = 1190 mm. Then, through the progression indicator, A1 and B1: A1 = A2/0.9 = 1322 mm; B1 = 319/0.9 = 354.5 = 355 mm. Next, sequentially, starting with B2 and A2, we multiply by the indicator until we reach 269 mm:

• B3 = B2*0.9 = 287 mm; A3 = A2*0.9 = 1071 mm.
• B4 = 258 mm; A4 = 964 mm.

Stop, we are already less than 269 mm. We check whether we can meet the gain requirements, although it is clear that we can’t: to get 12 dB or more, the distances between the dipoles should not exceed 0.1-0.12 wavelengths. IN in this case for B1 we have A1-A2 = 1322 – 1190 = 132 mm, which is 132/638 = 0.21 wavelengths of B1. We need to “pull up” the indicator to 1, to 0.93-0.97, so we try different ones until the first difference A1-A2 is reduced by half or more. For a maximum of 26 dB, you need a distance between dipoles of 0.03-0.05 wavelengths, but not less than 2 dipole diameters, 3-10 mm at UHF.

Note: cut off the rest of the line behind the shortest dipole; it is needed only for calculations. Therefore, the actual length of the finished antenna will be only about 400 mm. If our LPA is external, this is very good: we can reduce the opening, obtaining greater directionality and protection from interference.

Video: antenna for digital TV DVB T2

About the line and the mast

The diameter of the tubes of the LPA line on the UHF is 8-15 mm; the distance between their axes is 3-4 diameters. Let’s also take into account that thin “lace” cables give such attenuation per meter on the UHF that all antenna-amplification tricks will come to naught. You need to take a good coaxial for an outdoor antenna, with a shell diameter of 6-8 mm. That is, the tubes for the line must be thin-walled, seamless. You cannot tie the cable to the line from the outside; the quality of the LPA will drop sharply.

It is necessary, of course, to attach the outer propulsion boat to the mast by the center of gravity, otherwise the small windage of the propulsion boat will turn into a huge and shaking one. But it is also impossible to connect a metal mast directly to the line: you need to provide a dielectric insert of at least 1.5 m in length. The quality of the dielectric does not play a big role here; oiled and painted wood will do.

About the Delta antenna

If the UHF LPA is consistent with the cable amplifier (see below, about Polish antennas), then the arms of a meter dipole, linear or fan-shaped, like a “slingshot”, can be attached to the line. Then we get a universal VHF-UHF antenna excellent quality. This solution is used in the popular Delta antenna, see fig.

Delta antenna

Zigzag on air

A Z-antenna with a reflector gives the same gain and gain as the LPA, but its main lobe is more than twice as wide horizontally. This can be important in rural areas when there is TV reception from different directions. A decimeter Z-antenna It has small dimensions, which is essential for indoor reception. But its operating range is theoretically not unlimited; frequency overlap while maintaining parameters acceptable for the digital range is up to 2.7.

The design of the MV Z-antenna is shown in Fig; The cable route is highlighted in red. There in the lower left there is a more compact ring version, colloquially known as a “spider”. It clearly shows that the Z-antenna was born as a combination of a CNA with a range vibrator; There is also something of a rhombic antenna in it, which does not fit into the theme. Yes, the “spider” ring does not have to be wooden, it can be a metal hoop. "Spider" receives 1-12 MV channels; The pattern without a reflector is almost circular.

The classic zigzag works either on 1-5 or 6-12 channels, but for its manufacture you only need wooden slats, enameled copper wire with d = 0.6-1.2 mm and several scraps of foil fiberglass, so we give the dimensions in fraction for 1-5/6-12 channels: A = 3400/950 mm, B, C = 1700/450 mm, b = 100/28 mm, B = 300/100 mm. At point E there is zero potential; here you need to solder the braid to a metallized support plate. Reflector dimensions, also 1-5/6-12: A = 620/175 mm, B = 300/130 mm, D = 3200/900 mm.

The range Z-antenna with a reflector gives a gain of 12 dB, tuned to one channel - 26 dB. To build a single-channel one based on a range zigzag, you need to take the side of the square of the canvas in the middle of its width at a quarter of the wavelength and recalculate all other dimensions proportionally.

Folk Zigzag

As you can see, the MV Z-antenna is a rather complex structure. But its principle shows itself in all its glory on the UHF. The UHF Z-antenna with capacitive inserts, combining the advantages of “classics” and “spider”, is so easy to make that even in the USSR it earned the title of folk antenna, see fig.

Material – copper tube or aluminum sheet with a thickness of 6 mm. The side squares are solid metal or covered with mesh, or covered with a tin. In the last two cases, they need to be soldered along the circuit. The coax cannot be bent sharply, so we guide it so that it reaches the side corner, and then does not go beyond the capacitive insert (side square). At point A (zero potential point), we electrically connect the cable braid to the fabric.

Note: aluminum cannot be soldered with conventional solders and fluxes, so “folk” aluminum is suitable for outdoor installation only after sealing the electrical connections with silicone, since everything in it is screwed.

Video: example of a double triangle antenna

Wave channel

The wave channel antenna (AWC), or Udo-Yagi antenna, available for self-production, is capable of giving the highest gain, directivity factor and efficiency factor. But it can only receive digital signals on UHF on 1 or 2-3 adjacent channels, because belongs to the class of finely tuned antennas. Its parameters deteriorate sharply beyond the tuning frequency. It is recommended to use AVK under very poor reception conditions, and make a separate one for each TVK. Fortunately, this is not very difficult - AVK is simple and cheap.

The operation of the AVK is based on “raking” the electromagnetic field (EMF) of the signal to the active vibrator. Externally small, lightweight, with minimal windage, the AVK can have an effective aperture of dozens of wavelengths of the operating frequency. Directors (directors) that are shortened and therefore have capacitive impedance (impedance) direct the EMF to the active vibrator, and the reflector (reflector), elongated, with inductive impedance, throws back to it what has slipped past. Only 1 reflector is needed in an AVK, but there can be from 1 to 20 or more directors. The more there are, the higher the gain of the AVC, but the narrower its frequency band.

From interaction with the reflector and directors, the wave impedance of the active (from which the signal is taken) vibrator drops the more, the closer the antenna is tuned to the maximum gain, and coordination with the cable is lost. Therefore, the active dipole AVK is made into a loop, its initial wave impedance is not 73 Ohms, like a linear one, but 300 Ohms. At the cost of reducing it to 75 Ohms, an AVK with three directors (five-element, see the figure on the right) can be adjusted to almost a maximum gain of 26 dB. A characteristic pattern for AVK in the horizontal plane is shown in Fig. at the beginning of the article.

AVK elements are connected to the boom at points of zero potential, so the mast and boom can be anything. Propylene pipes work very well.

Calculation and adjustment of AVK for analog and digital are somewhat different. For analog, the wave channel must be calculated at the carrier frequency of the image Fi, and for digital - at the middle of the TVC spectrum Fc. Why this is so - unfortunately, there is no room to explain here. For the 21st TVC Fi = 471.25 MHz; Fс = 474 MHz. UHF TVCs are located close to each other at 8 MHz, so their tuning frequencies for AVCs are calculated simply: Fn = Fi/Fс(21 TVCs) + 8(N – 21), where N is the number of the desired channel. Eg. for 39 TVCs Fi = 615.25 MHz, and Fc = 610 MHz.

In order not to write down a lot of numbers, it is convenient to express the dimensions of the AVK in fractions of the operating wavelength (it is calculated as A = 300/F, MHz). The wavelength is usually denoted by the small Greek letter lambda, but since there is no default Greek alphabet on the Internet, we will conventionally denote it by the large Russian L.

The dimensions of the digitally optimized AVK, according to the figure, are as follows:

• P = 0.52L.
• B = 0.49L.
• D1 = 0.46L.
• D2 = 0.44L.
• D3 = 0.43l.
• a = 0.18L.
• b = 0.12L.
• c = d = 0.1L.

If you don’t need a lot of gain, but reducing the size of the AVK is more important, then D2 and D3 can be removed. All vibrators are made of a tube or rod with a diameter of 30-40 mm for 1-5 TVKs, 16-20 mm for 6-12 TVKs and 10-12 mm for UHF.

AVK requires precise coordination with the cable. It is the careless implementation of the matching and balancing device (CMD) that explains most of the failures of amateurs. The simplest USS for AVK is a U-loop from the same coaxial cable. Its design is clear from Fig. right. The distance between signal terminals 1-1 is 140 mm for 1-5 TVKs, 90 mm for 6-12 TVKs and 60 mm for UHF.

Theoretically, the length of the knee l should be half the length of the working wave, and this is what is indicated in most publications on the Internet. But the EMF in the U-loop is concentrated inside the cable filled with insulation, so it is necessary (for numbers - especially mandatory) to take into account its shortening factor. For 75-ohm coaxials it ranges from 1.41-1.51, i.e. l you need to take from 0.355 to 0.330 wavelengths, and take exactly so that the AVK is an AVK, and not a set of pieces of iron. The exact value of the shortening factor is always in the cable certificate.

IN lately domestic industry has begun to produce reconfigurable digital digital video cameras, see fig. The idea, I must say, is excellent: by moving the elements along the boom, you can fine-tune the antenna to local conditions reception. It is better, of course, for a specialist to do this - the element-by-element adjustment of the AVK is interdependent, and an amateur will certainly get confused.

About “Poles” and amplifiers

Many users have Polish antennas, which previously received analogue decently, but refuse to accept digital - they break or even disappear completely. The reason, I beg your pardon, is the obscene commercial approach to electrodynamics. Sometimes I feel ashamed for my colleagues who have concocted such a “miracle”: the frequency response and phase response resemble either a psoriasis hedgehog or a horse’s comb with broken teeth.

The only good thing about the Poles is their antenna amplifiers. Actually, they don’t let these products die ingloriously. Belt amplifiers are, firstly, low-noise, broadband. And, more importantly, with a high-impedance input. This allows, at the same strength of the EMF signal on the air, to supply several times more power to the tuner input, which makes it possible for the electronics to “rip out” a number from very ugly noise. In addition, due to the high input impedance, the Polish amplifier is an ideal USS for any antennas: whatever you attach to the input, the output is exactly 75 Ohms without reflection or creep.

However, with very bad signal, outside the zone of reliable reception, the Polish amplifier no longer works. Power is supplied to it via a cable, and power decoupling takes away 2-3 dB of the signal-to-noise ratio, which may not be enough for the digital signal to work in the outback. Here you need a good TV signal amplifier with separate power supply. It will most likely be located near the tuner, and the control system for the antenna, if required, will have to be made separately.

The circuit of such an amplifier, which has shown almost 100% repeatability even when implemented by novice radio amateurs, is shown in Fig. Gain adjustment – ​​potentiometer P1. The decoupling chokes L3 and L4 are standard purchased ones. Coils L1 and L2 are made according to the dimensions in the wiring diagram on the right. They are part of signal bandpass filters, so small deviations in their inductance are not critical.

Digital coding TV signal allows you to deliver it to the receiver, minimizing any losses. To support the technology, the TV needs an antenna for DVB-T2. Making such a device with your own hands is much cheaper than buying a ready-made one, paying about 3 thousand rubles for it. Terrestrial digital television displaces all similar types of signal transmission, while offering high-quality broadcasting and a variety of channels.

Changes on air

Making an antenna for an old-style tube TV was considered prestigious in its time and showed the level of skill, in modern world interest in homemade devices does not fade, and many make terrestrial antennas DIY DVB-T2. Manufacturers of industrial equipment adapt to changing reception conditions by connecting modern electronics to standard well-known designs, completely ignoring the fact that the main condition for the operation of the antenna is its interaction with the terrestrial signal.

In recent years, almost all broadcasting takes place in the DVB-T2 range, which reduces the cost and simplifies, from an economic point of view, the antenna-feeder system of transmission stations. Periodic maintenance requires less highly qualified personnel, and their work becomes less harmful and dangerous.

Television broadcast transmitters cover all large cities and sparsely populated villages with signals, so catching waves from unattended low-power stations in remote areas becomes important if you install an antenna for DVB-T2 reception, made with your own hands from scrap materials.

Due to the expanded construction of reinforced concrete buildings within the city, the conditions for signal propagation in populated areas have changed significantly. Multi-storey buildings with a metal frame are like mirrors, reflecting waves several times until they are completely attenuated.

There are many TV channels broadcast on the air today. A digital signal differs from others in that it either exists or it doesn’t; there is no middle position. Other transmission systems differ in that the channels perceive interference differently, which reduces their broadcast quality, and sometimes the image may simply disappear. A self-made antenna for DVB-T2 will allow you to receive the same signal for all channels that show the same high-quality picture.

The digital broadcasting signal is special in that it is not affected by interference; if it exceeds noise by one and a half decibels, then good welcome. Signal dropout is affected by cable mismatch or phase distortion at any point in the transmission from the camera to the tuner, and the image can be scattered into small pieces even with a strong signal.

Basic features for making an antenna

Before making DVB-T2 with your own hands, you should study the principle of its operation.

To capture a digital signal, it is required that it can be very simply constructed, even from a simple cable, after making the correct calculation.

The theory says that digital signals are easily transmitted in the UHF range and can be received by any type of antenna, but in reality this does not always work out.

You can make a television antenna yourself with minimal costs and without the help of strangers, but it should be remembered that the resulting device is inferior in reception quality to professional devices.

Requirements for antennas

New conditions for broadcasting, distribution and on-air reception have changed the basic requirements that DIY TV antennas must meet. DVB-T2 has abolished the previously significant directional and protective coefficients. In modern devices they do not matter, since the air is polluted, and even small penetrating interference can only be dealt with using electronic means. At the same time important role plays the antenna's own gain (GA).

An antenna that tracks the air well has a power reserve for the received signal, which allows the electronics to sift it from interference and noise. A modern antenna for DVB-T2, made with your own hands, preserves electrical parameters naturally, and does not adapt to acceptable parameters using engineering techniques. It is consistent over the entire operating frequency range without the use of balancing devices.

Antenna amplitude and frequency characteristics

The antenna is made as smooth as possible; phase distortions arise due to sharp emissions and dips. Single-frequency antennas are stretched to an acceptable noise-to-signal ratio, thus allowing them to receive up to 40 channels. But they are additionally equipped with matching amplifiers, which absorb waves or distort phase indicators.

The most effective digital DVB-T2 antenna is made by yourself:

• frequency-independent - with low performance, but cheap and easy to manufacture, constructed in a short period of time, intended for reception in relatively clean air on a short distance from the transmitting station;
• periodic band, catching all waves in space, ideally sorting them, which has a simple design, ideally works in tandem with a freeder throughout the entire reception range.

If we talk about the design, then the most simple antenna DVB-T2 is made with your own hands in the “eight”, “Polish” and “square” versions.

Figure-of-eight antenna

Refers to easily constructed devices, made like a standard figure eight, from which the reflector is removed. The ideal material is an aluminum strip, corner, tube, tire, or other profile. Top size 140 mm, side length 130 mm, but these dimensions are given as a guide; during manufacturing they should not be kept exactly to the millimeter.

To begin with, cut a wire 112 cm long, begin to bend the first part 140 mm long, of which 130 mm goes to the antenna, and 10 mm remains for the loop. The next two sections are bent equally to a length of 140 mm, the next two - 130 mm, the next pair - 140 mm, then another 140 mm, then - 130 mm and make a second loop. The connections are pre-cleaned, connected and soldered; they are also contacts for fastening the cable core.

Stripping the cable and plug is done using a scalpel and a file. After soldering, the joints are sealed and secured with glue from a hot gun. If we talk about the plug, then the glue is poured into the solder joint, then into the cavity of the cap, the excess is then removed. The joint is assembled so quickly that the adhesive mass does not harden. The result is an eternal, strong and elastic connection. To make contact, we strip the ends of the cable from the plug side by 1 cm, from the antenna side by 2 cm.

When connecting by soldering, a do-it-yourself indoor digital DVB-T2 antenna is also sealed with glue, where it is recommended to install a rigid frame at the point of contact according to the size of the joint. If the device is made for yourself and will be rigidly fixed during operation, and transfer is not needed, then the frame is not made. A device made of this type easily picks up digital signals in the direct line of sight of a television tower at a distance of up to 10 km when installed outdoors.

Using a “Polish” antenna

The “Polish” antenna received its name during the times of the former Soviet Union as a reliable device for receiving signals from Soviet television, as well as channels in the UHF range. Digital broadcasting is practically not received on it due to its low efficiency. Some amateurs are trying to bring the design to ideal by shortening the long decimeter mustache and removing the reflector. Such a change in some cases allows you to adjust the image in digital format, but talking about guaranteed receipt there is no reliable result. Speaking about Polish devices, we can note the high-quality operation of the amplifier, which works effectively with a digital signal.

Antenna type "square"

This DIY indoor DVB-T2 antenna is a modified copy of the standard design, known as “three squares,” which has six components and a matching transformer. A homemade antenna of this type confidently copes with the reception of TV channels digital format up to 10 km in a straight line, longer distances require a signal booster.

The antenna design is simple to implement. The main structural element consists of round aluminum wire and single-core wires. The wire is bent to obtain six squares and a matching tap is made, which is a transformer high frequencies so that the signal matches the cable and the DVB-T2 antenna with the amplifier. With their own hands they solder the wires to the points, wrap them with copper wire and tin them with a soldering iron.

The cable is attached to the antenna with special clamps or using ordinary insulating tape. The cable is connected by placing a support, using a wooden plank or other material. When installing indoors or outside a building, the main condition is precise alignment with the television tower. This is done using a navigator; if there is no line of sight, the direction is clarified until the effect of receiving a powerful signal.

Antenna made from beer cans

The manufacturing technology is like this efficient antenna very simple and does not require special skills.

Using a thick awl or screwdriver, make neat holes in the neck of each of the two cans, then screw screws into them. The cable ends are freed from the braid, the copper wires are cleaned of varnish with a knife, and they are attached under the screw heads. It is very good to solder the resulting connection, but not necessary.

The DVB-T2 digital antenna is almost made with your own hands; it remains on the prepared rail or pipe to secure the cans so that there is a distance of 7.5 cm between them. The second cable end is equipped with a standard plug that is connected to the receiver; the device is installed in the place where the signal is best recorded. Placing this type of device outdoors requires reliable protection from the weather. This is done with any waterproof material, often plastic bottles are used. large size. The antenna receives up to 15 channels satellite television and digital broadcasting.

Using Instruments and Amplification

At a certain distance from the television tower, the antenna is capable of receiving signals without installing additional amplifying devices. To receive a signal from greater distance stocked with a wave amplifier with separate power supply. The device is installed near the tuner, and the matching device is made additionally; for its manufacture you need:

• potentiometer for gain adjustment;
• standard decoupled throttles L4 and L3;
• coils L2 and L1 are wound according to dimensions from the directory;
• a metal screen to separate the output circuits from the device circuit.

The amplifiers are placed no further than 3 meters from the place where the DVB-T2 cable antenna is installed, which receives power from its own unit with its contacts. When installing an antenna near a broadcasting tower, it is not recommended to use an additional amplifier, since a strong signal degrades the image and has an additional effect on the entire structure. The recommended cable length is three meters; a larger wire will lead to imbalance of the balun.

Application of a symmetrizer

This device is needed for any type of antenna, and it does not matter whether it was made at a factory or in a craftsman’s workshop. Antenna for DVB-T2, made by yourself, gives good quality images when connected to a tuner. If the cable length is more than 10 m, then when installed outside the building, inconsistencies in the resistance of the external space and the cable arise. In this case, it is necessary to use a balunizer in a comprehensive antenna solution, which greatly improves the quality of the image on the screen.

Cable laying and antenna installation

The main rule is to install the antenna at a height. If this cannot be done in the room, you need to move the device to an external wall. To install an antenna in a private building, digital broadcasting operators rely on a device height of 10 m. If the antenna is located on the ground floor of a house, then nearby metal structures and industrial objects cause poor reception.

When placing the antenna under a canopy or the roof of a house, pay attention to the roofing material - it should not contain a metallized coating or spraying. Metal tiles, corrugated sheets, iron or foil insulation create significant interference with signal reception digital television.

For high-mounted receiving antennas on a metal mast or pin, a steel rod of at least one meter in size is provided, to which a grounding wire is connected. The device located on the roof is included in common system grounding of the house.

The cable is not routed through smoke and ventilation ducts, and is not hung on existing electrical wires, even if they look more than reliable. The holes in the walls are placed at an angle so that moisture from the street does not flow into the room; special commercially available plugs are used. If the antenna is made well and correctly, take a cable and wall sockets of high quality, since after the final finishing of the walls it is difficult to redo the cable in the wall and replace it with a more reliable one.

Compliance with safety precautions when installing the antenna

Before installing or adjusting an already mounted antenna at a height, make sure that this action is safe:

• do not climb onto weakly secured and shaky structures; if working at height is associated with danger, be sure to wear a mounting belt and attach it to a fixed part of the building structure;
• The assistant is not allowed to hold the end without first securing it; if he falls, the assistant will not be able to hold his body weight in his hands;
• It is forbidden to climb to a height alone, when structures are icing, to walk on an old roof, or to step on connecting seams;
• It is prohibited to install the antenna in rain and fog.

In conclusion, it should be said that it is quite easy to do it yourself receiver in order to watch digital television. DVB-T2, a home-made antenna, is almost as good in quality (if you follow the right technology) as store-bought counterparts. The cost of materials will allow you to save a decent amount of money, which is important for some people.

High-quality antennas have always been difficult to obtain - the Soviet industry practically did not produce them, so people made them themselves from improvised materials. Today the situation has practically not changed - in stores you can only find light 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 and quality reception No? The answer is simple -Given free time and a pair of skillful hands, anyone can handle this.

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

Create homemade antenna for the digital range it is possible at home

This was done for reasons of economy and safety - maintenance of transmitting antenna-feeder stations is virtually not required, their maintenance is reduced to a minimum, and the harm from contact with powerful transmitters for masters is minimal. But similar stations have one serious drawback- low power. And if in a big city the signal can often be caught even for a segment copper wire, reception may be difficult away from the transmitter. 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 dampened 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 before reaching the TV receiver.

It's also worth noting that DVB-T2 (the new TV standard) offers a fairly constant but weak signal. When the noise level is one and a half to two units higher than normal, the TV reproduces the broadcast 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 a mismatch occurs anywhere in the system, the picture stops or falls apart. High qualitywill solve this problem, but in some cases it will have to be taken outside or onto the roof.

Basic requirements for antennas

The current television standards in the USSR are not suitable for modern realities— protective and directional coefficients today have virtually no effect on signals. The airwaves in cities are clogged and contain a lot of dirt, so you shouldn’t pay attention to these coefficients. You are guaranteed to get interference on any antennas, so there is no need to reduce the efficiency factor and efficiency factor. It is better to improve the antenna gain so that it receives a wide range of airwaves 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.

So, Experienced engineers recommend building band antennas. They must be correctly calculated, receiving signals in a classical way, and not through engineering “optimizations” and traps. Ideal option— 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 that is smooth and even, since when the amplitude-frequency response dips or jumps, phase distortions appear.

Attention: analog Antennas with ferrite USS, which provide full reception of the old signal, practically do not work with DVB. What you need to build is a “digital” antenna.

In the article we will analyze modern types antennas working with new digital broadcasting.

Antenna types

DIY antennas for digital TV Can you assemble it at home? There are three most common options:

1. All-wave, or as radio amateurs call it, frequency-independent. It assembles very quickly, does not require high knowledge or specialized tools. Well suited for the private sector, villages, dacha cooperatives - where the airwaves are not clogged with garbage, but not too far from the transmitter.
2. Log-periodic range. It has a simple design and receives the signal well at close and medium distances from the transmitter. Can be used as a remote antenna 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 “zeshki” - 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.

Nuances of construction

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

You also need to deal with points of zero potential, where currents arise even in the absence of voltage. Experts recommend making them from a single piece of metal, without using welding at all. Even well-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 figure out how to solder cables. Today, copper is practically not used for braiding, since it is expensive and quickly oxidizes. Modern braiding is made of steel, which is not afraid of corrosion, but it is very difficult to solder. It should not be overheated or squeezed. For connections, use 36-40 watt soldering irons, flux and light solders. Dip the winding well into the flux and apply solder - it takes up perfectly 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 anything 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 eliminating plates and using PCB. It needs to be given the appropriate shape or simply 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 right angles. Zero potential is on the extreme line home antenna for tv , just at the intersection of the cable with the vertical guide. To avoid loss of quality, the cable must be tied to it with a tie - this is enough for coordination. Such an antenna, hung outside or directed at a window, receives virtually the entire frequency range, but has a slight dip, so you need to set the correct angle when fixing the antenna.

By the way, this design can be modernized using ordinary aluminum beer and cola cans. The principle of its operation is as follows: as the shoulder span increases, the working band expands, although other indicators remain within the original limits. The Nadenenko dipole, often used in military developments, works on the same principle. Aluminum cans are ideal in shape and size, creating vibrator arms in the decimeter range.

You can create a simple can antenna by simply soldering two cans to a cable. This DIY indoor TV antenna Suitable for viewing channels at a short to medium distance from transmitters. There is no need to coordinate anything in this scheme, especially if the cable length is less than 2 meters.

You can complicate the design by assembling a full-fledged array from eight cans and using an amplifier from a regular Polish antenna. This design is perfect for hanging outdoors in areas remote from the transmitter. To enhance the signal, a metal mesh can be placed at the back of the structure.

Z antenna

Complex Z-antenna designs with multiple loops exist, 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 3 mm single-core copper wire 120 mm long - this will be enough for your work. This design consists of two segments. We bend the wire according to this pattern:

1. The starting section is 14 centimeters long. Its edge is bent into a loop to connect with the last one (the loop is 1 cm, the total length of the first piece is 13 cm).
2. The second piece is bent at 90 degrees (it is better to bend it with pliers to maintain 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 thoroughly strip the two loops and solder them. The opposite corner is also cleaned. The cable contacts are soldered to them - one is central, the other is braided. There is no difference which contact to solder to.. It is advisable to insulate the soldered areas; 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.

To avoid displacement of segments, the edges can be strengthened. To do this, take a regular plastic cap from a five-liter bottle, cut 4 slits in it so that the wire is recessed to the base. Cut the fifth hole for the cable. Then place the antenna in the cover (after checking the quality and reliability of the soldering), and fill it with hot-melt adhesive. 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 an antenna for a TV. In fact, the structures are much larger than those we described, but even these will be quite enough for you. If you live far from the signal source, then you will need amplifying antennas - you can get by with a classic “polka” with amplification. Well, if everything is bad with the airwaves, then use satellites.

A super simple and super quick to make antenna from a coaxial cable for receiving digital television channels can be made with your own hands in about 5 minutes. For this you will need absolutely nothing except the cable itself. And this is the main advantage of this antenna.
You can't live without a TV now.

This design will definitely help you out, for example, when you have just moved into your home and have yet to install a cable or install a stationary antenna. Of course, this is not the only example where this truly simple loop antenna will help.
Now in the comments someone will definitely write that there are even simpler antennas, like a whip one. To make it, it will be enough to simply remove two insulations from the cable and everything will work. Of course, I agree with this, but the loop antenna that I will make from coaxial cable will have much greater gain, due to its directivity and resonant closed circuit.

Making an antenna from coaxial cable

Antenna location

The test showed excellent results

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:

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 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.

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.

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 with copper wire Ø 0.8 mm (2.5 turns must 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.

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 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 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.
• The 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”.

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 “digits” (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.