Digital coding of a television signal allows you to deliver it to the receiver, minimizing any loss. To support the technology, the TV needs an antenna for DVB-T2. Do it yourself is much cheaper to make such a device than to buy a ready-made one, having paid about 3 thousand rubles for it. On-air digital television displaces all similar types of signal transmission, while offering high-quality broadcasting and a variety of channels.
Changes on the air
To make an antenna for an old-style lamp TV set at one time considered prestigious and showed a level of skill, in the modern world, interest in home-made devices does not fade, and many people make DVB-T2 broadcast antennas with their own hands. Manufacturers of industrial equipment are adapting to the changing reception conditions by connecting modern electronics to standard well-known designs, completely ignoring the fact that the main condition for the antenna to work is its interaction with the broadcast 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 economy of transmission stations. Periodic maintenance requires fewer highly qualified personnel, their work becomes less harmful and dangerous.
Television broadcasting transmitters cover all major cities and sparsely populated villages with signals, so it’s important to catch waves from unattended low-power stations in the wilderness if you install a DVB-T2 antenna yourself made from improvised materials.
Due to the expanded construction of reinforced concrete structures within the city, the conditions for the propagation of signals in settlements have significantly changed. Multi-storey buildings with a metal frame are a kind of mirrors, several times reflecting the waves until complete attenuation.
A lot of TV channels are broadcast on modern air. A digital signal differs from the rest in that it either is or is not, a middle position is not given. Other transmission systems differ in that the channels perceive interference in different ways, which is why their broadcast quality is reduced, sometimes the image may simply disappear. An antenna for DVB-T2, made by yourself, will allow you to receive the same signal for all channels that show the same high-quality picture.
The digital broadcast signal is special in that it is not affected by interference, if it is one and a half decibels higher than noise, then good reception is achieved. The disappearance of the signal is affected by inconsistency with the cable or phase distortion in any part of the transmission from the camera to the tuner, while the image may crumble into small parts even with a strong signal.
Basic Features for Antenna Manufacturing
Before you make a DVB-T2 antenna yourself, you should study the principle of its operation.
To capture a digital signal, a decimetric antenna is required , which is very simple to construct even from a simple cable, making the correct calculation.
The theory says that digital signals are easily transmitted in the decimeter range and can be received by any type of antenna, but in reality this does not always work out.
It is possible to make a television antenna on your own at minimal cost and without the help of outsiders, but you should remember that the resulting device is inferior to professional devices in the quality of reception.
Antenna Requirements
New conditions for broadcasting, distribution and reception on the air have changed the basic requirements that do-it-yourself TV antennas must meet. DVB-T2 canceled previously significant directional and protective factors. They are not important in modern devices, since the ether is contaminated, and it is possible to fight even with small penetrating noise only by electronic means. At the same time, an antenna gain (KU) plays an important role.
The antenna, which tracks the broadcast 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 by one’s own hands, preserves electrical parameters in a natural way, and does not adapt to acceptable parameters using engineering techniques. It is consistent across 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 stretch in an acceptable ratio of noise to signal, thus exposing them to receive up to 40 channels. But to them are additionally installed matching amplifiers that absorb waves or distort phase performance.
The most effective digital antenna DVB-T2 do-it-yourself is made:
- frequency-independent - with low performance, but cheap and easy to manufacture, designed in a short period of time, designed to be received in relatively clean broadcast at a small distance from the transmitted station;
- periodic range, captures all the waves in the open, ideally sorting them, which is characterized by a simple design, works perfectly together with the feeder for the entire length of the reception.
If we talk about the design, then the simplest DVB-T2 antenna is manufactured in the “eight”, “Polish” and “square” versions.
Eight Antenna
Refers to easily designed devices made according to the type of standard eight, with which the reflector is removed. The ideal material is copper wire, but an aluminum strip, corner, tube, bus, other profile are used. The upper size is 140 mm, the lateral part is 130 mm long, but these dimensions are for reference only, they should not be kept exactly to the millimeter during manufacture.
To begin with, they 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 of 140 mm, then another 140 mm, then 130 mm and make a second loop. The joints are pre-cleaned, connected and soldered, they are also contacts for fastening the cable core.
The cable and plug are stripped using a scalpel and needle file. After soldering, the joints are sealed and fastened with glue from a hot gun. If we talk about the plug, then the glue is poured into the adhesive 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 solidify. It turns out an eternal strong and elastic connection. For contact, we clean the ends of the cable from the side of the plug by 1 cm, from the side of the antenna by 2 cm.
Do-it-yourself digital DVB-T2 digital antenna, when soldered, is also sealed with glue, where it is recommended to install a rigid frame at the junction size at the contact point. If the device is made for itself and will be rigidly fixed during operation, and the transfer is not needed, then the frame is not made. A device made of this type easily picks up digital signals on a straight line of sight of a television tower at a distance of up to 10 km for outdoor installation.
Using a “Polish” Antenna
The "Polish" antenna got its name in the days of the former Union as a reliable device for receiving signals from Soviet television, as well as channels in the decimeter range. Reception of digital broadcasting on it is practically not carried out due to low efficiency. Some lovers try to bring the design to an ideal by shortening a long decimeter mustache and removing the reflector. Such a change in some cases allows you to adjust the image in digital format, but it is impossible to talk about guaranteed receipt of a reliable result. Speaking of Polish devices, one can note the high-quality operation of an amplifier that works effectively with a digital signal.
Type of antenna "square"
Such a self-made DVB-T2 indoor antenna is a modified copy of the standard design, known as the "three squares", which has six components and a matching transformer. A home-made antenna of this type confidently copes with the reception of digital-format TV channels at a distance of up to 10 km in a straight line, for longer distances a signal amplifier is required.
The antenna design is simple to implement. The main structural element consists of round-section aluminum wire and single-core wires. The wire is bent to obtain six squares and a matching tap is made, which is a high-frequency transformer so that the cable and the DVB-T2 antenna with the amplifier are combined according to the signal. With their own hands, they solder the wires to the points, wrap them with copper wire and tin with a soldering iron.
The cable is attached to the antenna with special clamps or with an ordinary insulating tape. The cable is connected with the support, using a wooden plank or other material. When installing indoors or outdoors, the main condition is the fine tuning to the television tower. This is done using the navigator, if there is no line of sight, the direction is specified before the effect of receiving a powerful signal.
Beer can antenna device
The manufacturing technology of such an effective antenna is 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 the screws into them. The cable ends are freed from the braid, the copper wires are cleaned with a knife from the varnish, they are attached under the caps of the screws. It is very good to solder the resulting compound, but not necessarily.
The DVB-T2 digital antenna is almost made with its own hands, it remains to fix the banks on the prepared rail or pipe so that there is a distance of 7.5 cm between them. The second cable end is equipped with a standard plug connecting to the receiver, the device is installed in the place of the best signal fixation. Placing this type of device on the street requires reliable protection from the weather. This is done with any waterproof material, often large plastic bottles are used. The antenna receives up to 15 channels of satellite television and digital broadcasting.
Use of instruments and amplification
At a certain distance from the television tower, the antenna is able to receive signals without installing additional amplifying devices. To receive a signal from a greater distance, they are stocked by a wave amplifier with separate power supply. The device is arranged near the tuner, and the matching device is made additionally, for its manufacture it is necessary:
- potentiometer for gain adjustment;
- standard chokes L4 and L3;
- coils L2 and L1 are wound in size from the directory;
- a screen of metal to separate the circuits at the output from the circuit of the device
Amplifiers are placed no further than 3 meters from the place where the DVB-T2 antenna is installed from the cable, which receives power from its own unit with the contacts of the antenna cable . When installing the antenna near the broadcasting tower, it is not recommended to additionally use an amplifier, since a powerful signal degrades the image and has an additional electronic load on the entire structure. The recommended cable length is three meters, a larger wire will lead to an imbalance of the balancer.
The use of a balancer
This device is needed for any type of antenna, while it does not matter, they made it at the factory or in the workshop of a craftsman. The antenna for DVB-T2, made by hand, produces good image quality if it is connected to the tuner. If the cable length is more than 10 m, then when installing outside the building, inconsistencies in the resistance of the external space and the cable arise. In this case, it is required to use a symmetrizator in the integrated solution of antenna management, which greatly improves the image quality on the screen.
Cable routing and antenna installation
The main rule is to set the antenna to a height. If this cannot be done in the room, you need to take the device to the outer wall. To install the antenna in a private building, digital broadcasting operators rely on a device height of 10 m. If the antenna is located on the first floor of the house, the nearby metal structures and industrial facilities cause reception degradation.
When placing the antenna under a canopy or roof of the house, pay attention to the roofing material - it should not contain a metallized coating or spraying in the composition. Metal tile, decking, iron or foil insulation creates significant interference with the reception of digital television signals.
For highly placed receiving antennas, a steel rod of at least one meter in size is provided on a metal mast or pin to which a ground wire is connected. The device located on the roof is included in the general grounding system of the house.
The cable is not led out 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 inclined, so that moisture from the street does not flow into the room, use special plugs available on the market. If the antenna is made soundly and correctly, they take a cable and high-quality wall outlets, since after the final decoration of the walls it is difficult to remake the cable in the wall and replace it with a more reliable one.
Observance of safety measures when mounting the antenna
Before installing or adjusting an already mounted antenna at a height, make sure that this action is safe:
- do not climb on loosely fixed and shaky structures, if high-altitude work is dangerous, they must put on a mounting belt and fasten it to the fixed part of the building structure;
- it is not allowed to hold the end of the mounting belt to the assistant, without first securing it; in the event of a fall, the auxiliary does not hold the weight of the body in hands;
- it is forbidden to rise to a height alone, when icing structures, walk on the old roof, step on connecting seams;
- Do not install the antenna in rain or fog.
In conclusion, it should be said that it is quite simple to make a receiving device on your own in order to watch digital television. DVB-T2 - a self-made antenna, - in quality (if you follow the right technology) is almost not inferior to store counterparts. The cost of materials will save a decent amount of money, which is important for some people.