Digital coding of the TV signal allows you to deliver it to the receiver, minimizing any loss. The TV needs a DVB-T2 antenna to support the technology. 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 replaces 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 at one time and showed the level of skill, in the modern world, interest in home-made devices does not fade away, and many make DVB-T2 terrestrial antennas with their own hands. Manufacturers of industrial equipment are adapting to 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 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,antenna-feeder economy of transmission stations. Periodic maintenance requires fewer highly trained personnel, making their work less harmful and dangerous.
TV broadcast transmitters cover all major cities and sparsely populated villages with signals, so catching waves from unattended low-power stations in remote areas becomes important if a do-it-yourself DVB-T2 antenna is installed, made from improvised materials.
Due to the expanded construction of reinforced concrete buildings within the city, the conditions for signal propagation in settlements have changed significantly. Multi-storey buildings with a metal frame are a kind of mirrors, reflecting waves several times up to complete attenuation.
A lot of TV channels are broadcast on the air today. A digital signal differs from the rest in that it either exists or it does not exist, there is no middle position given. Other transmission systems differ in that the channels perceive interference differently, which reduces their broadcast quality, sometimes the image may simply disappear. A DIY antenna for DVB-T2 will allow you to receive the same signal for all channels that show the same quality picture.
Digital broadcasting signal is special in that it is not affected by interference, if it is one and a half decibels higher than the noise, then good reception is carried out. The signal disappearance is affected by cable mismatch or phase distortion in any section of the transmission from the camera to the tuner, while the image may scatter intosmall parts even with strong signal.
Basic features for making an antenna
Before you make a DVB-T2 antenna with your own hands, you should study the principle of its operation.
To capture a digital signal, a decimeter antenna is required, which is very simple to construct even from a simple cable, having made the correct calculation.
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 is not always the case.
You can make a television antenna yourself at minimal cost and without the help of outsiders, but you should remember that the received device is inferior to professional devices in terms of reception quality.
Antenna Requirements
The new conditions of broadcasting, distribution and reception on the air have changed the basic requirements that do-it-yourself TV antennas must meet. DVB-T2 has canceled previously significant directional and protective factors. They do not matter in modern devices, since the air is polluted, and even small penetrating interference can be de alt with only by means of electronics. At the same time, the antenna's intrinsic gain (GA) plays an important role.
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 by hand, retains electrical performance in a natural way, and notadapts 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 occur due to spikes and dips. Single-frequency antennas are stretched in an acceptable noise-to-signal ratio, thus allowing them to receive up to 40 channels. But matching amplifiers are additionally installed to them, which absorb waves or distort phase indicators.
The most efficient do-it-yourself DVB-T2 digital antenna is made:
- frequency-independent - with low performance, but cheap and easy to manufacture, designed in a short period of time, intended for reception in relatively clear air at a short distance from the transmitted station;
- periodic band, catching all waves in space, ideally sorting them, which has a simple design, ideally works in tandem with a frieder throughout the entire length of the reception.
If we talk about the design, then the simplest DVB-T2 antenna is made by hand in the "eight", "Polish" and "square" options.
Figure 8 Antenna
Refers to easily constructed devices, made like a standard figure eight, from which the reflector is removed. The ideal material is copper wire, but aluminum is usedstrip, corner, tube, tire, other profile. The top size is 140 mm, the side part is 130 mm long, but these dimensions are given as a guide, during manufacture 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 each, the next pair 140 mm each, 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 attaching the cable core.
Stripping the cable and plug is done with 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 solder joint, then into the cavity of the cap, then the excess is removed. The joint is assembled so quickly that the adhesive mass does not harden. 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 DVB-T2 indoor digital antenna, when soldered, is also sealed with glue, where it is recommended to install a rigid frame at the contact point according to the size of the joint. 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 in the direct line of sight of a television tower at a distanceup to 10 km outdoor.
Using a "Polish" antenna
The "Polish" antenna got its name in the days of the former Soviet Union as a reliable device for receiving Soviet television signals, as well as channels in the decimeter range. Reception of digital broadcasting on it is practically not carried out due to low efficiency. Some amateurs are trying to bring the design to the ideal by shortening the long decimeter mustache and removing the reflector. Such a change in some cases makes it possible to adjust the image in digital format, but it is impossible to speak of a guaranteed receipt of a reliable result. Speaking about Polish devices, we can note the high-quality work of the amplifier, which effectively works with a digital signal.
Antenna type "square"
This DIY indoor DVB-T2 antenna is a modified copy of the standard design, known as the "three squares", which has six components and provides a matching transformer. A self-made antenna of this type confidently copes with receiving digital TV channels at a distance of up to 10 km in a straight line, for longer distances a signal amplifier is required.
The design of the antenna is simple in execution. The main structural element consists of round aluminum wire and solid wires. The wire is bent to obtain six squares and a matching tap is made, which is a high-frequency transformer,to combine the signal cable and DVB-T2 antenna with an amplifier. 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 ordinary insulating tape. The cable is connected with a support, a wooden plank or other material is used. When installing indoors or outdoors, the main condition is precise tuning to the television tower. This is done using the navigator, if there is no line of sight, the direction is specified to the effect of obtaining a strong signal.
Beer can antenna device
The manufacturing technology of such an efficient antenna is very simple and does not require special skills.
Using a thick awl or a 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 varnish, they are attached under the caps of the self-tapping screws. It is very good to solder the resulting joint, but not necessary.
The do-it-yourself DVB-T2 digital antenna is almost made, it remains on the prepared rail or pipe to fix 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 attaches to the receiver, the device is installed in place the best signal capture. Placing this type of device outdoors requires reliable protection from the weather. This is done by anyonewaterproof material, large plastic bottles are often used. The antenna receives up to 15 channels of satellite TV and digital broadcasts.
Using fixtures and amplification
At a certain distance from the TV tower, the antenna is able to receive signals without installing additional amplifying devices. To receive a signal from a greater distance, they are stocked with a wave amplifier with separate power supply. The device is arranged near the tuner, and the matching device is made additionally, for its manufacture you need:
- potentiometer for gain adjustment;
- standard decoupled chokes L4 and L3;
- coils L2 and L1 are wound according to the dimensions from the reference book;
- metal shield to separate the output circuits from the device circuit.
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 its contacts of the antenna cable. When installing the antenna near the broadcasting tower, it is not recommended to additionally use an amplifier, since a strong signal worsens the image and puts additional electronic load on the entire structure. The recommended cable length is three meters, a larger wire will unbalance the balun.
Using a symmetrizer
This device is needed for any type of antenna, it does not matter whether it was made at the factory or in the craftsman's workshop. Antenna for DVB-T2, made by hand,produces good picture quality 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 outer space and the cable occur. In this case, it is required to use a symmetrizer in the complex solution of the antenna economy, which greatly improves the quality of the image on the screen.
Cable laying 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 an external wall. To install an antenna in a private building, digital broadcast 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, industrial objects cause reception degradation.
When the antenna is located under a canopy or roof of the house, pay attention to the roofing material - it should not contain a metallized coating or sputtering in the composition. Metal tiles, corrugated board, iron or foil insulation create significant interference with the reception of digital television signals.
For highly located receiving antennas on a metal mast or pole, a steel rod of at least one meter in size is provided, 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, it is not hung on existing electrical wires, even if they look more than reliable. Holes in the walls are inclined, soso that moisture from the street does not flow into the room, use special plugs that are commercially available. If the antenna is made well and correctly, they take high quality cable and wall sockets, since after the final finishing of the walls it is difficult to remake the cable in the wall and replace it with a more reliable one.
Antenna Mounting Safety Practices
Before installing or adjusting an already mounted antenna at a height, make sure that this action is safe:
- do not climb onto weakly fixed and shaky structures, if working at height is associated with danger, be sure to put on a mounting belt and attach it to a fixed part of the building structure;
- it is not allowed to hold the end of the mounting belt to an assistant without first securing it, if the helper falls, the helper will not hold the weight of the body in his hands;
- it is forbidden to climb to a height alone, when structures are iced, walk on the old roof, step on the connecting seams;
- It is forbidden to install the antenna in rain and fog.
In conclusion, it should be said that it is quite simple to make your own receiving device in order to watch digital television. DVB-T2 - a do-it-yourself antenna - in quality (if you follow the right technology) is almost as good as store-bought counterparts. The cost of materials will save a decent amount of money, which is important for some people.
