Homemade antennas for receiving digital TV. A simple but effective indoor antenna for digital television reception

). Thus, an antenna is a kind of transmitter (receiver). In this article we will understand what antenna is needed for receiving DVB-T2 signal.

Antenna types:

By type, antennas can be divided into indoor, outdoor and long-distance antennas. We are interested in antennas that able receive standard signal DVB-T2. They can be divided into two groups: indoor and outdoor. In turn, they are divided into active and passive.

The digital terrestrial television signal of the DVB-T2 standard is transmitted in decimeter ( DMV) range. This range (UHF) is within 470–862 MHz. In Russia, these frequencies fill the channels from 21st to 69th television channel (TVK) inclusive.

We would like to immediately make a reservation that there are no special antennas for DVB-T2 reception, all these are ordinary decimeter antennas with or without a signal amplifier. Choose An antenna for DVB-T2 reception will not be difficult. There are two main criteria to consider here: distance to the transmitter and relief terrain. Two services will help us with this:

Next, we proceed directly to the selection of a DVB-T2 UHF antenna. If the terrain of your area is more or less flat and the distance to the transmitter is no more than ten kilometers, then the usual UHF antenna without amplifier. Although, if the price difference is not big, then we recommend purchasing an active antenna (with an amplifier), because you can always turn it off.

Indoor DVB-T2 antennas:

As an example of a passive indoor DVB-T2 antenna, let's take the Sirius 2.0 antenna, manufactured by REMO. You can read it on our website.

As an example of an active indoor DVB-T2 antenna, let’s take the “MINI DIGITAL” antenna, from the same manufacturer “REMO”. You can also find it on our website.

Outdoor DVB-T2 antennas:

Outdoor antennas are also classified into active and passive. They must be used when the distance from the transmitter is more than 10 kilometers. It is recommended that these antennas be pointed accurately at the transmitting station.

As an example of an outdoor DVB-T2 antenna, let's take the SELENA MINI antenna, manufactured by REMO.

As an example of an outdoor active DVB-T2 antenna, let’s take an antenna made by REMO.

Outdoor DVB-T2 antennas for long-distance reception:

If the distance to the transmitting equipment is over 30 kilometers, then you will need highly directional antennas with increased sensitivity. These antennas can receive signals at a distance of up to 100 kilometers. Also do not forget that such antennas must be installed on an appropriate height.

As an example of an outdoor active DVB-T2 antenna for long-distance reception, let’s take an antenna made by REMO.

Television today is in every home. With the development of technology, the quality of television signals and methods of their transmission change. And if just yesterday antediluvian analogue broadcasting was used, today exclusively digital broadcasting is persistently discussed.
In Russia, television and radio broadcasting is carried out by the state company RTRS. Since 2012, a government decree has recognized a single standard digital terrestrial television DVB-T2, multiplex digital broadcasting standard. The RTRS company, as the only on-air operator, offers two multiplex packages (RTRS-1 and RTRS-2) to free viewing. All you need is a modern receiver-antenna, one of the options of which today we propose to make with your own hands.

This homemade product is based on the development of engineer Kharchenko K.P., who proposed similar antennas for the decimeter range (DCV), popular in the 90s of the last century. This is the resemblance aperture antennas, based on a zigzag-shaped irradiator. The signal is accumulated by a flat reflector, which is at least 20% larger in size than the vibrator.
The television signal is transmitted by waves with horizontal polarization. In a simplified form, such an antenna consists of two horizontal loop vibrators connected to each other in parallel, but disconnected at the feeder (cable) connection point. Overall dimensions are given on the basis of Kharchenko’s article “Antenna of the DCV range”, and are calculated according to the proposed formulas. According to this technology, such antennas can be designed even for a weak signal of about 500 MHz.

What is needed to assemble the antenna

Materials:

• Barbecue grill;
• Aerosol paint for cars;
• Solvent or acetone;
• A set of drills for a conventional drill;
• Coaxial tv cable– no more than 10 m;
• Half a meter PVC pipes HV, diameter – 20 mm;
• Metal dowels for drywall;
• Copper wire for the antenna vibrator, core diameter – 2-3.5 mm;
• Two thin metal plates.

Tools:

• Soldering iron powerful 100 W;
• Screwdriver with attachments;
• Hot glue gun;
• Pliers, hammer, wire cutters;
• Painting knife, tape measure, pencil.

Let's start making the antenna

Making a vibrator frame

We measure the required length of copper wire with a margin of about 1 cm. You can also use a copper or aluminum tube with a diameter of up to 12 mm.

We clear the copper core from the insulation and level it with a hammer on a hard surface. Mark the middle and make a 90° bend. The most accurate way to do this is in a vice, lightly pressing the copper core and leveling it with a hammer.

According to our calculations, the sides of the squares will be 125 mm. We mark them with a tape measure and make bends.

Using side cutters, we bite off a small fragment from one end, making the tip pointed at 45°. After bending the second square, we carry out the same procedure, biting off the final end of the core. The squares can be slightly bent for this purpose.

On the middle bends of the squares we achieve a distance of 10-12 mm. At the ends we make shallow cuts with a needle file. This will help us pull both free ends together and secure them with thin copper wire.

Using liquid rosin or flux, we tin the middle bends with a soldering iron. This must be done on all sides of the copper core of the vibrator.

We strip the coaxial cable by 4-5 cm. We twist the braid or outer conductor into a single wire and wrap it around one of the bends. We solder it to the copper core with a soldering iron.

We strip the insulation of the inner conductor and also wrap it around the next bend of the frame. You need to solder it carefully, holding the insulation with pliers, since the temperature can simply move it away from the center. We first heat the frame in the soldering zone, and only then the conductor itself.

We fix the coaxial cable connection with a nylon tie, degrease it with a solvent and isolate the soldering points with hot glue using a gun. You can correct defects in the resulting cast form of glue with a hairdryer.

Preparing the reflector

We use an inexpensive barbecue net as a reflector or reflective screen. This is a good material, since even steel samples of such products are covered with a corrosion-resistant anodized coating, not to mention stainless steel. A heat exchanger from a modern refrigerator or a dish drying rack would also be suitable. The main thing is that this element, if possible, does not rust in the air.
The reflector grid must be larger than the vibrator frame, but does not have to be symmetrical. We cut off the handles from the grille; they will be superfluous in our design.

We place the antenna frame in the middle of the reflector and mark its mounting locations. For fastening, you can use two plates of any metal. We bend them along the grid and drill holes with a diameter of 5 mm.

Assembling the antenna

We cut two pieces of PVC pipe 75 mm long, and screw a self-tapping screw into the end of each, cutting off the protruding parts. We break off the pointed ends of the plasterboard dowels and screw them into the opposite end of the tubes.

We screw both PVC stands to the strips on the reflector with self-tapping screws. We tin the frame at the ends suitable for the racks for better heat transfer.

On the racks we mark the height of 68 mm, and put it at risk. We heat the ends of the frame with a soldering iron and solder them into the racks to the required marks.

Digital terrestrial television - good budget alternative satellite TV. Its main advantages are the ideal picture and sound quality and the absence of a subscription fee. For reception you only need a set-top box (receiver) and an antenna for digital television, and excellent images are guaranteed with any TV. An impeccable image is achieved through a qualitatively different method of signal transmission than in the case of analog television. The digital signal is not subject to interference and interference and is much less dependent on the distance to the transmitter.

What channels can I receive with a digital TV antenna?

IN first and second already available today in Moscow and in many regions for free reception of multiplexes (packages) of channels, 20 federal ones are included (Channel One (1TV), "Russia-1", "TVC", "NTV", "Channel 5" (St. Petersburg) , “Russia-2”, “Russia-24”, “Russia-Culture”, “Carousel”, “OTR” (1st multiplex); “REN-TV”, “STS”, “Domashny”, “TV-” 3", "SPORT-PLUS", "SPAS", "STAR", "MIR", "TNT", "MUZ-TV" (2nd multiplex). The broadcasting area of ​​the third federal multiplex of 10 channels continues to expand. During 2015 the third multiplex was launched, total number at least 10 channels, including HD. Digital television is already broadcast in more than 80 regions of Russia.

Antenna for digital television - how to choose?

Depending on the location of installation, antennas can be indoor or outdoor, respectively for home and garden. They are also divided into active and passive, depending on the presence of a built-in signal amplifier operating from the network. If you live near a TV tower, passive (without an amplifier) ​​reception is recommended. indoor antenna: Amplifying the signal may cause distortion. When moving away from the TV tower, for example at a dacha or in country house and the presence of obstacles (trees, buildings), an external antenna with a built-in or external signal amplifier is required. The main condition when choosing an antenna for digital television should be reliable reception in the UHF range. Attention, you can find outdoor antennas in the section Outdoor antennas for digital television

Is it possible to make the antenna work for two TVs?

You can connect two or more TVs to one antenna for digital television. However, if you use one receiver for reception, then each TV will show the same channel. To watch different channels at the same time, you need to purchase receivers for other TVs.

The delivery department will deliver the goods you have chosen to any point in Moscow and the Moscow region.

Digital television these days continues to spread every day. Providers offer their services in this area by selling expensive devices. However, you can “catch” terrestrial digital television using a homemade antenna.

We invite you to watch a video on making an antenna:

So, we need:
- decimeter antenna;
- calculator;
- antenna cable;
- cable connector;
- ruler

First of all, it should be noted that to receive digital TV channels you need a TV that supports the DVB-T2 format, otherwise the antenna will not fulfill its purpose. It should also be clarified that providers often advertise so-called digital antennas, which are supposedly created specifically for receiving digital TV channels. This is not true, since you can catch such channels even with a wire. Now that you've sorted out the materials and the introductory part, you can get to work.

Next, we find our district or city on the website to find out the advisory support center or, more simply put, the broadcasting center. The next thing is to call the support center and find out on which channel the digital television is broadcast. The author, for example, broadcasts on channel 27. At the end of this stage, we find out the channel frequency.

Now, using a calculator and a special formula, we have to find out the required length of our antenna. The formula is extremely simple: 7500 must be divided by the number of channel frequencies. The author’s channel frequency is exactly 522000 kHz, that is, you need to divide 7500 by 522. It turns out to be approximately 14.3. We round the result obtained after division and get the length of the antenna in centimeters.

Next, take a regular antenna cable, strip it on one side and insert the connector.

The next thing is to take a ruler and measure the result obtained by dividing, leaving 2 centimeters at the base. That is, if the author needs a cable 14 centimeters long, he measures 2+14 cm.

Cut off the end. After this, we make a cut on the base line and clean it to the edge. We remove the cable protection because we don’t need it. We also cut off the foil.

After this, we bend the cable at the base line at a right angle. The antenna is ready. All that remains is to install it outside so that it faces the transmitting antenna. It is worth noting here that if the distance from the transmitting antenna is more than 15 km, then you will have to use an antenna amplifier.

Today, the DVB-T digital standard has been used for broadcasting television signals. To receive broadcasts on analog TVs, you can make an antenna for digital TV with your own hands, which is connected to a special set-top box that converts the signal.

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Requirements for a digital packet television antenna

To ensure signal reception and transmission to the amplifier, the antenna must meet the following requirements:

1. The collecting elements must be located along the axis of the waves coming from the transmitter.
2. Have protection against interference with a frequency close to the television signal. Sources of interference may be other radio signals, interference from operating electric motors and generators.
3. The antenna design should minimize signal power loss during transmission.
4. The antenna circuit must be oriented according to the type of polarization.

Types of TV antennas

Antennas for receiving television signals are divided into several types, differing in the frequencies of the received signals.

The following types are widespread:

1. An all-wave antenna that can receive digital and analog signals. Reception distance analog signals is not large and does not exceed the line-of-sight range of a television tower.
2. Log-periodic antenna capable of receiving meter and decimeter waves.
3. A decimeter antenna designed to receive only short waves.

The author of the video, Dmitry, will talk about making a simple antenna for digital TV.

How to find out the initial data for calculating an antenna

The key parameter on which the quality of reception depends digital signal, is the wavelength of the radiation. Based on this length, select dimensions antenna whiskers. To determine the wavelength, a calculation is used using the formula λ=300/F, where F is equal to the frequency of the transmitted signal in MHz. This parameter is publicly available and can be easily installed through any Internet search engine.

Made from a cardboard box

The simplest version of a home antenna, which you can quickly make yourself using available materials, is a device based on a cardboard shoe box.

For production you will need:

• food grade aluminum foil;
• a piece of standard coaxial cable;
• masking or stationery tape;
• a tube of quick-drying glue, for example, rubber “Moment”.

The manufacture of the antenna is as follows:

1. Cut the foil to the shape of the bottom of the box. Lubricate the box with glue and stick the foil, smoothing it evenly along the bottom.
2. Cut two pieces of coaxial cable 500 mm long.
3. Remove the cable shielding insulation from each end to a distance of no more than 25 mm.
4. Move the screen and twist it into a separate core.
5. Bend each segment into a circle shape.
6. Secure the sections on the outside of the box lid in the shape of a number 8 using tape. The ends of the cable should be directed towards the center of the figure eight and located at a distance of at least 10 mm from each other.
7. At a length of about 100 mm, strip external insulation cable that will connect the antenna to the receiver.
8. Twist the screen into a separate core.
9. Gradually remove the insulation of the central conductor until a section of bare wire with a length of about 95-100 mm is obtained.
10. Pierce the bottom of the box along with the foil and insert the cable inside.
11. Lead the wire through the cover and run it along the contour of one of the parts of the “eight” to the central part. Secure the cable.
12. Connect three braid strands together. Then fasten the three terminals of the central wire. Re-secure the knot with tape.
13. Install the plug on reverse end coaxial cable.
14. Place the antenna in place best regards, which is determined empirically.

If everything is done correctly, the antenna will allow you to receive the main television channels in DVB T2 format. The photo below shows the main stages of antenna manufacturing.

Covering the bottom with foil Laying rings on the lid Main cable supply Connection of conductors

How to make an all-wave antenna

Those who want to save on purchases can make an antenna for receiving a digital signal themselves by choosing one of the designs described below.

From coaxial cable

The simplest antenna design can be considered a piece of coaxial cable 2-3 m long, which has a plug at one end. The free end is cleared of the outer layer of insulation, the screen is woven into a separate conductor and taken to the side. Then the insulation of the central wire is cut off in small pieces. After this, the wire is placed on a window or sill, selecting appropriate place empirically.

It should be noted that this design is only effective at a range of reliable reception, where the singal is quite powerful. If you are far away from the repeater or the receiver is located in a densely built area, it is necessary to use other antenna designs.

Of two petals

This version of the TV antenna is made from a pair of small metal plates having the shape isosceles triangle, and two wooden or plastic slats. Copper wire with a diameter of 2-4 mm is stretched between these elements.

Lobe antenna circuit

The pitch of fastening the wire on the slats is 25-30 mm. The triangular bases are connected to each other by soldering at a distance of 10 mm from each other, the wire is also soldered to the triangles. To connect to the television receiver, a coaxial cable RK75 is used. The wire screen is connected to the rail (the place is indicated by a yellow dot), and the central wire is connected to the junction of the triangles. In areas of poor reception, it is recommended to use the antenna in conjunction with an amplifier.

Butterfly

For more stable reception of the terrestrial television signal, a “butterfly” antenna is used. Homemade device similar design can be used at home and in the country. It will provide good quality reception only with a stable broadcast signal.

To make a receiving device, you will need materials and tools from the list:

• a board with a length of at least 600 mm and a width of about 70 mm, the thickness can be any, but preferably 15-20 mm;
• single-core copper wire with a conductor diameter of at least 4 mm;
• wood or metal screws and washers;
• coaxial cable RK75;
• plug connector for antenna;
• roulette;
• side cutters;
• Phillips screwdriver;
• wire stripper;
• soldering iron with a power of 40-60 W;
• solder and flux for soldering.

A do-it-yourself digital TV antenna is assembled as follows:

1. Mark the board that will serve as the antenna frame in accordance with the schematic drawing below. The distance between the vertical rows of holes is 25 mm. The holes are located at the same distance from the edges of the board.
2. Cut the wire into 8 pieces of 375 mm and two pieces of 220 mm.
3. Remove approximately 25mm of insulation from the center of each long piece.
4. Bend the cables into a V shape with equal lengths. The distance between the ends should be 75 mm.
5. Install the V-shaped sections on the board using self-tapping screws. For tight fixation, washers should be placed under the heads of the screws.
6. Before tightening the screws, install additional short connectors. On short wires, it is necessary to remove the insulation at the points of contact with the V-shaped conductors.
7. Connect the coaxial cable to the bottom row of screws. The installation diagram is shown below.

Can antenna with protective cover

How to make a log periodic antenna

To make the frame of such a device, the following are used:

• aluminum U-shaped profile with a side height of about 15 mm;
• studs with a suitable diameter and length or smooth tubes and rods are used as antenna whiskers;
• a small piece of aluminum tube with a diameter of 10-15 mm, which is used as a support.

The sequence of manufacturing a simple antenna is as follows:

1. Flatten the tube at both ends and bend it into a U shape. One flattened end should be attached to the U-shaped profile using self-tapping screws.
2. Make pairs of antenna whiskers with lengths of 70, 85, 100, 120, 140 and 170 mm. Cut a thread on one side.
3. Drill holes in the U-shaped profile to install the mustache. The distances between the holes are indicated in the diagram.
4. Screw a nut onto each whisker and install the assembled part into the hole of the U-shaped profile.
5. Secure the mustache inside the profile using nuts. Place a connecting terminal under each nut, which can be factory-made or homemade from a copper conductor.
6. Solder the mustache outputs in a certain sequence (shown in the diagram).

Ring antenna diagram: 1 - ring, 2 - additional loop, 3 - main cable

In the form of a frame

Another option is a frame structure called a Kharchenko antenna, made of thick copper wire with a diameter of 30-4 mm.

The antenna assembly looks like this:

1. Cut the wire 112 cm long.
2. Strip and tin the ends of the wire that will be bent into loops.
3. Bend it in the form of two rectangles in the following sequence - a fixation loop of 10 mm, then a rib 130 mm long, then two ribs of 140 mm, two of 130, two of 140, the last rib is 130 mm long and ends with a loop that The last 10 mm of wire goes away.
4. Connect the loops at the ends and solder the joint.
5. Move this angle apart from the opposite one by 20 mm (shown in the photo below). Tin the wire located opposite the joint of the loops.
6. Strip the coaxial cable 20 mm for the screen and 10 mm for the central core.
7. Solder the leads to the tinned corners on the frame.
8. Make a central body from plastic cover suitable size.
9. Place the squares of the frame with the cable into the housing and fill it with hot glue. After the glue has hardened, install the antenna in the place of best signal reception.

To calculate the parameters of the Kharchenko antenna, there are specialized online calculators that calculate all the product data.

Amplifier based on the MAX2633 circuit

To make an amplifier, you will need three capacitors with a capacity of 1 nF and a resistance with a nominal value of 1 kOhm. To power such a device, a constant voltage of 3 to 5 V is used. The device does not require adjustment, but the degree of amplification is adjusted by setting a resistance of a different value (to reduce the degree of amplification, it is necessary to increase the resistance). Such an amplifier is not broadband and is applicable only for the shortwave range.

For wideband amplification when receiving a signal on long distances transistor devices are used circuit diagrams which are given below.

Amplifier based on the common emitter of the KT368 transistor Amplifier based on the common base of the KT315 transistor Two-transistor amplifier

In progress self-assembly similar devices need to be manufactured printed circuit boards with paths. When using wires to connect elements, the amount of interference increases, which will reduce the gain of the device.

For an amplifier based on KT368 you will need resistances and capacitors with the following parameters:

• 100 Ohm (R1 and R4);
• 470 Ohm (R2);
• 51 kOhm (R3);
• 1000 pF (C1);
• 33 pF (C2);
• 15 pF (C4 and C3).

The assembled amplifier is installed as close as possible to the receiver and can be used for any type of antenna. It does not need configuration and works from the source direct current with a voltage of 9 V.

To expand the frequency range, amplifiers built on a common transistor base are used. These devices also do not require additional adjustment of operating parameters.

During the assembly process you will need the following components:

• 51 Ohm (R1);
• 10 kOhm (R2);
• 15 kOhm (R3);
• 1 kOhm (R4);
• The capacitors have the same rating as in a common emitter circuit.

The amplifier circuit uses a choke coil, which is wound from 300 turns of 0.1 mm wire (PEV type) on a ferrite ring.

In the case of a very weak signal, it is possible to use multi-stage circuits operating from direct current with a voltage of 12 V and built on two transistors of the GT311D type.

The amplifier circuit for long-range antennas uses:

• 680 Ohm (R1);
• 75 kOhm (R2);
• 1 kOhm (R3);
• 150 kOhm (R4);
• 100 pF (C1, C2, C4);
• 6800 pF (C3);
• 15 pF (C5);
• 3.3 pF (C6);
• 100 µH (L1);
• 25 µH (L2);
• homemade choke made of 25 turns of PEV2 wire with a diameter of 0.8 mm (L3).