Methods for manufacturing DVB-T2 antennas for receiving digital television

If you do not want to buy
a DVB-T2 antenna for digital TV , you can make it yourself using available tools. Since there is no design that could successfully function in various conditions, you need to choose the most suitable version of a home-made device, depending on the specific situation.

Simple Antennas

If there is an urgent need to build a DVB T2 antenna, and the list of improvised materials is limited, you can assemble an elementary device yourself.

“Tin” (can) antenna

Assembles quickly and easily. For good reception, you need a high-quality signal without barriers. The greatest effect can be obtained in suburban areas and small towns. For manufacturing you need:

• beer cans – 2 pcs.;
• screwdriver, bolts, self-tapping screws;
• plug, cable;
• copper wire (small piece);
• adhesive tape or insulating tape;
• wooden sticks – 2 pcs.

For the antenna, it is necessary to make a cruciform frame from wood. Then we perform the following steps:

1. We make holes for the bolts in the middle of the bottom of the cans.
2. We remove the cable insulation without affecting the outer contour, equal in length to three jars + another 20 cm.
3. We stretch the cable through one hole to another, setting the cans with their necks in parallel. We fix the cable at the end with a bolt or self-tapping screw.
4. We fix the cable from the hole and its bare part between the banks and the wire.
5. We fix the jars with tape or insulating tape (one turn is enough) to the frame bar, located horizontally.
6. We attach the plug.

When bending, do not damage the cable, otherwise you will not get a good signal. Do not skimp on the bare cable section – you have a margin of 0.2 m.

Now we determine the required interval between jars. We connect the plug and move them along the bar until a stable signal is received. As a rule, the greatest effect is achieved at a distance of 7 cm from one jar to another. After that, we firmly attach them to the contour. If the antenna is used outdoors, it is necessary to cover it with polyethylene or make a plastic frame. You can mount the device on a hook. If more than 2 cm of bare cable remains at the exit from the hole, wrap the excess section with insulating tape. How to make a simple antenna out of cans is shown in this video: https://www.youtube.com/watch?v=kt8u3U-Hp8g

“The loop”

The active part is the TV cable. This antenna is made like this:

1. Disconnect the cable from the faulty antenna.
2. We clean up the end.
3. We measure 0.4 m, remove the insulation by 20 mm, trying not to harm the external circuit.
4. The bare area and the segment that was cleaned are tightly fastened in parallel with wire.

The result should be a circle (a little more than 0.15 m in diameter) from the cable as a receiver. After that, in the center opposite the side of the bonding point, measure 40 mm and remove the insulation. Now the antenna can be used. The disadvantage of the device is its noise, since the cable end is open. But for temporary use, such an antenna will do. How to make a simple cable loop antenna is shown in the video below: https://www.youtube.com/watch?v=XdD3nANJbQY

For such an antenna, it is necessary to have a T2 tuner or the TV must have a built-in T2.

Antenna out of the box

The starting material for the manufacture of the device is a cardboard box. We cut out 2 rectangles of 0.25×0.3 m from it. You also need to prepare:

• TV cable with plug;
• bolts, nuts (2 pcs.);
• screwdriver, razor blade;
• wire (preferably copper);
• food paper or foil;
• glue (clerical is suitable).

We cut out 2 squares from food paper (the perimeter should be like cardboard blanks). Glue them firmly to the cardboard blank. We remove the rest of the glue.

When applying foil to cardboard, avoid gaps and protrusions, otherwise reception will be poor.

The squares made will become the receiving part of the antenna. Now we connect the cable. With a blade we make holes for the bolts – at the corners of the squares (adjacent sides). Then we draw the inner contour to one of the holes, and the outer contour (metal casing) to the other. We fasten the contacts with bolts. We find a stable reception by connecting the cable to the TV. We move the squares while maintaining the parallelism of adjacent sides. Having found the required distance, we attach the squares to the frame. Watch the video showing step by step how to make such an antenna: https://youtu.be/gwqKRAePtZw

Use the device only as
an indoor antenna , as the foil does not withstand the external environment well.

Z-antenna – decimeter antenna for digital television DVB-T2

This homemade device is also called “Square”, “People’s Zigzag”, “Rhombus”. The figure below shows a simplified version of the classic zigzag. To increase sensitivity, it is equipped with capacitive inserts (1, 2) and reflector A. If the signal level is acceptable, this is not required. To make an antenna with your own hands, you will need tubes made of copper, aluminum, brass or strips of 0.1-0.15 m. When installing the structure outdoors, aluminum is least suitable for this because of its susceptibility to corrosion. For the manufacture of capacitive inserts, foil, tin or metal mesh is suitable. After installation, they need to make contour soldering.

Cable laying should be carried out without sharp bends and within the side insert.

The classic version of the Z-antenna is characterized by operation on 1-5 or 6-12 channels. To make it, you need to stock up:

• wooden slats;
• copper enameled wire 0.6-1.2 mm;
• scraps of fiberglass (foil), dimensions for the corresponding 1-5 / 6-12 channels:
  • A = 340/95 cm;
  • B, C = 170/45 cm;
  • b = 10/2.8 cm;
  • H = 30/10 cm.

E – this point is characterized by zero potential – the braid must be soldered to the metallized plate for support. Reflector parameters (also for corresponding channels 1-5/6-12):

• A \u003d 62 / 17.5 cm;
• B = 30/13 cm;
• D = 320/90 cm.

Another diagram and additional explanations that will help in assembling the antenna are presented below:

Do-it-yourself tunable active antenna for digital TV:

https://youtu.be/l1PuJLS7BlM

figure eight antenna

It is considered one of the most commonly used homemade devices for receiving digital TV. She also has another name –
Kharchenko’s antennaor a biquad. It is a double diamond-shaped square. This device can be successfully used in various conditions, with the exception of super-dense buildings, as they interfere with the reception of reflected signals. When designing the “eight” it is necessary to make the correct calculations, taking into account the wavelength. All sides of the square and the half-length of the wave section must match. As a consequence, the perimeter will be equal to the length of the wave itself. For example, for a DTV in the metropolitan area, it will be 0.6 m, respectively, one side is 0.15 m. To make such an antenna, you need to stock up on copper (2-3 mm) or aluminum (5-6 mm) wire. According to the design concept, it will be necessary to manufacture two squares. It is necessary to cut off 2 cm from the wire ends and fasten them to each other so that

Be sure to isolate the fastened ends of the wire pairs from each other, otherwise the antenna will only emit a signal.

For the frame, a simple beam is usually used. If all actions are performed correctly, the receiver is immediately firmly fixed, since it is not necessary to check the functionality. The cable is soldered exactly in the middle, at the junction of the wire ends to one of the points. Watch the video on how to make a biquadratic antenna with your own hands: https://www.youtube.com/watch?v=3o0ZBUcL2f0

Three-element or four-element wave channel

The classic type of “wave” three-element antenna is characterized by the presence of the following components:

• director, which has the smallest length and is directed towards the TV tower;
• rectangular vibrator;
• reflector.

Gain device – up to 6 dB. The antenna is capable of picking up a reflected DVB-T2 signal from a television center approximately 5 km away or in direct vision up to 30 km. Not giving a lot of gain, such a device is not suitable for long-range reception of the indicated signals. To increase the gain, you need to equip the structure with ten or more elements. It is very difficult to make such an antenna yourself. It is optimal to have three or four elements. The algorithm of actions is as follows:

1. It is necessary to stock up on copper wire or a tube from 0.2 to 0.5 cm in diameter. We solder the reflector, director and vibrator to the guide of the device.
2. The structure is attached to a dielectric pole located next to the cable. The antenna is coordinated with it by a section of the antenna cable – a U-elbow, with a wave resistance of 75 ohms. Its length is multiplied by the shortening factor inherent in the brand of cable used.
3. The antenna vibrator is soldered on both sides with the central cores of the U-elbow. The latter are connected in the same way to the screens of the outgoing cable, and its central core is connected to the antenna vibrator.

The addition of one director will help to increase the gain by a maximum of 2 dB, which will give a four-element antenna at the output and increase the stable reception area by several kilometers.

The manufacturing process of a three-element “wave channel” antenna is shown in this video: https://www.youtube.com/watch?v=aLY0_7brvbo

Double (triple) square

Self-manufacturing of this antenna is similar in calculations with a biquad device. The design feature is the arrangement of several identical squares one after the other. The main difference from the G8 antenna is the lack of reception of a stable signal from a TV repeater, which is removed at a considerable distance. The purpose of the double (triple) square is to receive signals at a high radiation background. Often a television tower in highly compacted buildings, although it is close, there may be other receiving towers of various frequencies that jam the decimeter wave. This homemade device is capable of receiving waves of a certain length without problems, and the multilevel design of the device serves as an amplifier. Squares are easily mounted on a bar. To mount the device vertically,

Connect the squares to each other not on the active site, but only with the help of outgoing fuel cells. If this does not work out, expose the cable more and solder it to the bottom corners of the squares, then fasten it to the bar.

After completing the assembly of several squares, temporarily fix them and, by changing the distances between them, reveal the optimal signal reception, then fix them firmly. How to make an antenna from several biquads to increase the gain is shown in this video: https://youtu.be/6mCVeQgPqvE

Antenna DVB T2 “Butterfly” (“Moth”)

Structurally, such an antenna is characterized by antennae located vertically. In some ways, such devices are similar to pin factory devices for digital TV made in Poland, but differ in that they use a frame instead of a phased array. To make a “butterfly” with your own hands, you need to stock up:

• drill and screws;
• ruler and protractor;
• wire cutters;
• wire (6 mm) made of aluminum 3 m long;
• bolts with nuts (16 pcs.) or a soldering iron;
• wooden stick.

As a rule, Polish-made digital TV antennas are designed for outdoor installation, which means that this design will also need to be installed outdoors. To withstand strong winds, it is better to use not copper (3 mm) wire for long antennae, but thicker aluminum.

Digital TV programs operate with 21 physical TV channels (frequency 314 MHz, wavelength 0.63 m). This correlates with the maximum repeater radiation of the RTRS. The required length of the active area is 0.16 m, for all the “antennae” – 2.56 m. Therefore, a three-meter wire will be enough.

The stick is used as a frame, its length must be at least 0.6 m. On the frame, it is necessary to make markings for the “antennae”. This is done like this:

1. We mark 4 points at an equal (0.2 m) distance.
2. We draw lines from the points, they should lie parallel to one another and perpendicular to the frame.
3. We measure adjacent angles of 30 degrees (2 to the left and 2 to the right) from straight lines and put points.
4. We draw lines at an angle to the designated points from the central ones. These lines will serve as a pointer to install the “antennae”.

Taking into account the half-length of the wave cross section of 0.15 m, we will analyze two options for the independent manufacture of such an antenna.

Making using a soldering iron

In this case, the construction of the structure will take much less time. Metal products are fixed in parallel on a wooden stick. For this, 4 pieces of steel are used (they are subsequently connected) or wire. To see the markup of the TE, it is necessary that the wooden frame remains open. The places of antennal adhesions will serve as the main points on the markup, and the lines drawn at an angle will serve as their location. We take the wire, cut off 16 segments (0.15 m each) with wire cutters and solder the antennae made from them, grouped in 4 pieces, to all the indicated points.

It is desirable that all groups of elements are wrapped with insulating tape.

Bolting

In this embodiment, no metal additions to the wooden structure are required – accordingly, the device will be lighter. The stick is chosen with the following parameters: width – 4 cm, thickness – from 2 cm. First, “pits” for the antennae are prepared with a drill. They are made on the side of the stick at an angle inward along the line on the markup. After that, holes are drilled through and through along the tangent of the pits. The frame is done. We cut off pieces of 0.17 m from the wire (with a margin), deepen the prepared antennae into the holes by 2 cm, then firmly fix them with nuts and bolts. We wrap the antennae with a thin wire, connect each other.

Making an antenna in this way takes more time, but the output is more durable than soldered design.

How to make a bolt-on butterfly antenna is shown in this video: https://www.youtube.com/watch?v=zGpHdvDyt6s

Antenna N. Turkina for receiving digital television

The device consists of 6 rings of metal wire, which serve as active vibrators and passive elements and are fixed on a dielectric guide. This antenna has better reception performance than the triple square, so it is often installed for long-range reception of DVB-T2 signals. N. Turkin’s antenna is narrow-band, so precise settings will be required during its installation. It must be installed in the region where there is only one multiplex (if there are two, then they must be on close channels). When they are spread over a larger number of channels, the reception will be of poor quality. The device consists of the following parts:

• dielectric rod on which the installation is carried out;
• directors D1÷D3 with reflector R – passive elements;
• V1, V2 – vibrators;
• ferrite rings (put on the cable near the connection to the vibrators) – a matching device.

The connection of active vibrators is based on the Swiss square: a cross-shaped connection of rings with lower cuts from below.

For installation you will need:

• determine the DVB-T2 frequency range;
• make an accurate calculation of the dimensions of the device;
• make parts, solder the electrical circuit.

The initial frequency data and channel numbers for calculation can be found on the services of DVB-T2 television operators. We will consider digital television on channel 40, a frequency of 626 MHz. Distance (L) between elements – 29, 72, 96, 60, 96 mm (total – 353 mm). The circumferences are 470, 465, 460, 484, 489, 537 mm.
Having decided on the parameters, let’s get to work:

1. We select a bar of wood (its length should be slightly more than 353 mm) for an insulating rod, copper wire (preferably 2.5 sq. Mm. And 4 m long).
2. We mark the holes on which the rings will be attached, and drill them.
3. We manufacture active vibrators and passive elements. We cut the copper core along the circumference of each ring. We bend all the segments into rings. For active vibrators, the ends of the rings are made with a gap, so we increase the length of the segments by 8 cm, bend them at a right angle to the side. We solder crosswise to the beginning of the next.
4. We make the cascades of passive elements shorter, subsequently mounting them on a dialectical rod. We solder the ring ends.
5. We install the directors in the traverse. We pass a jumper made of thin copper, push the vibrator ring on both sides. We wrap the jumper over the tinned place on both sides and solder it.
6. Installing vibrators.
7. Install reflector.
8. We connect the cable.
9. We check the quality of the reception.

Before you start manufacturing an antenna for digital TV, you need to know which one will best accept the DVB-T2 format. After reviewing several types of homemade antennas, you can choose the best option for your case.