Indoor decimeter antennas for digital TV. Do-it-yourself "wave channel" antenna for MV and UHF, calculation and diagram. All you need to make is
Digital television T2 is gaining momentum in popularity. And this is natural, analogue television is being replaced by digital television and this is an irreversible process. Moreover, in the near future, analogue broadcasting will be stopped altogether. What should users who have TVs without a T2 receiver and no cable television do? The answer is simple - buy a T2 set-top box. Today, the price of T2 consoles has dropped greatly and does not look exorbitant. The advantages are quite large: you get many channels in digital quality, without a monthly fee, at minimal costs and without buying a new TV. Only by comparing the quality of digital and analog TV will you never regret your choice.
Quite a lot has been written on the choice of T2 receivers. Moreover, new models are constantly being released. I would advise you to take an inexpensive, but new model, after reading reviews on online store sites. As a rule, any receiver works, but the antenna is of great importance. Even if you are close to a TV tower, but are blocked by high-rise buildings, etc. - and this is almost always the case, then a good antenna is the key to problem-free (and most importantly, stress-free) high-quality reception of the maximum number of digital TV channels.
But an expensive antenna is not always a good antenna. Especially if you are 50 km or more away from the TV tower. Stores offer “special” antennas for T2. In fact, there is nothing “special”; you need a good antenna for the DCM range. If you still have an old DCM antenna, try connecting it first. Widespread "Polish" antennas are not suitable for receiving T2 digital channels.
I offer a proven option that is simple, but at the same time has proven itself, homemade antenna for T2. The shape of the antenna is not new; it has been used for a long time and when receiving DCM analog television, but the dimensions are optimized for receiving T2 digital channels.
It is worth noting that the Internet offers a large number of options for homemade antennas for T2: from beer cans, from the antenna cable itself, a converted Polish one, etc. This is for the completely lazy, and you shouldn’t expect quality from such antennas.
So. The long-known “figure eight” was taken as the shape of the antenna. The antenna body is made of any conductive material of suitable cross-section. This can be copper or aluminum wire with a thickness of 1 to 5 mm, a tube, strip, busbar, corner, profile. Copper is, of course, preferable. I used 6mm diameter copper tube. Copper wire is also a good option. I just had such a pipe.
Dimensions
The outer side of the square is 14 cm, the inner side is slightly smaller - 13 cm. Due to this, the middle of the two squares does not converge, leaving a gap of about 2 cm.
In total, you will need a tube, wire or other material 115 cm long (with a small margin).
The first section is 13 cm + 1 cm for a loop (for strength), if made of wire, or riveted for overlapping soldering for a tube. The second and third - 14 cm each, the fourth and fifth - 13 cm each, the sixth and seventh - 14 cm each, and the last eighth - 13 cm + 1 cm, again for connection.
We strip the ends by 1.5 - 2 cm, twist the two loops behind each other, and then solder the joint. This will be one cable connection pin. After 2 cm another.
From a copper tube it looks like this
It’s a little more difficult to bend the tube, but we don’t need much precision. Minor flaws in the shape do not affect the performance of the antenna. But the fact that the conductor area increases is a plus. Well, the conductivity of copper is higher than that of aluminum and, especially, steel. The higher the conductivity, the better the antenna reception.
The connection prepared for soldering is first riveted and cleaned. For soldering you need to use a powerful soldering iron (from 150 W). Simple amateur radio at 30 watts. don't solder. You can use acid for soldering.
Check the geometry again and solder the connection
If you are not particularly bothered by the aesthetic appearance, you can simply attach the antenna to a glazing bead or any other available holder. This antenna was located in the attic, so the simplest mounting method was used - electrical tape. If the antenna will be placed outdoors, take care of more aesthetic and reliable mounting.
This is a version of the T2 antenna made of aluminum wire with a diameter of 3 mm. Secure with one screw to the window. The distance to the TV tower is about 25 km. True, it’s the 6th floor, I didn’t check it below, but under these conditions the signal level is 100% and the quality is 100%. The cable is old, 12 meters to the TV. Receives all 32 channels. At first I was worried that it wasn’t copper, but as it turned out, it was in vain. Everything worked out perfectly on ordinary aluminum wire (which happened to be available). That is, if you have a reliable reception zone, then you don’t have to bother and feel free to use aluminum (I don’t know, maybe steel will do).
This antenna does not use any amplifiers. It is set up very simply - turn it according to the maximum signal level and quality on the channels of your tuner. Check other channels and fix the antenna. If reception is poor, you can experiment with not only rotating, but also changing location and height. Very often, the signal can be many times stronger if the antenna is shifted only 0.5-1 m to the side or in height. Good luck - the antenna has been tested - 100% operational and better than at least half, or even more, of purchased antennas, where they save on everything and sell garbage for good money.
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
This is what the version made from black cable looks like.
Now let's start making the antenna in order. All we need is less than half a meter of coaxial cable of any color. I took the white one.
We retreat 5 cm from the edge of the cable and remove the top insulation.
Next, remove the insulation from the central core.
Now we twist everything together neatly and tightly.
Then, from the edge with the insulation removed, we retreat 22 cm and cut out a 2 cm piece of the top insulation and the shielded wire from the hose, without touching the insulation of the central core.
Now we measure another 22 cm from the end of the cut and make a cut 1 cm wide only by removing the top insulation. We do not touch the cable shield.
Next, take the end of the cable from which we started. And we wrap it very tightly at the last cut, forming a circle of the antenna.
At this point, our antenna is ready for use. Of course, this is not necessary, but if you hang the antenna outside, it is better to insulate all exposed areas of the cable with electrical tape. You can also add a rigid frame, but this is optional.
Antenna location
We direct the antenna to a repeater or television tower. The direction can also be selected experimentally by rotating the antenna.The best option would be to place it outside the window, since the walls of the house greatly dampen the high-frequency signal.
The test showed excellent results
Which antenna to choose for digital television? How are antennas different? How to supply power to an active antenna? Which antenna is better? These and other questions on the site
Hi all! Due to my line of work, I have to deal very closely with connecting and setting up antennas for digital terrestrial television.
Therefore, based on the experience gained, I have the opportunity to share how to choose an antenna for digital television and set up dvb-t2 - free 20 channels.
Quick navigation through the article
Which antenna is suitable for DVB-T2 digital television
With the advent of digital terrestrial television, many people have questions related to the choice of antenna for DVB-T2. For example!
- Can I use my old antenna, if I had one?
- Is an antenna of the “Lattice” type, also known as “Polish”, suitable for this?
- Do I need an antenna with or without an amplifier?
- if there is a question about purchasing a new one?
- Is the advertised “Key to Free TV” antenna necessary?
Let's first figure out what kind of antennas there are.
Antennas of the meter (MV) and decimeter (UHF) ranges are used to receive television signals. There are broadband antennas, this is a “hybrid” when elements of the MV and UHF bands are used in the antenna design.
These antennas are easy to distinguish from each other by size.
The MV range has longer elements. Everything is according to the name.
So in MV antennas the elements are approximately half a meter to one and a half meters in length.
And the elements of the UHF antenna are only about 15 to 40 cm long.
It is the UHF antenna that is needed for digital terrestrial television.
VHF Antenna 
Example of a UHF antenna 
Broadband antenna, MV and UHF ranges. 
Array antenna 
Broadband antenna "Hummingbird" So - To receive digital terrestrial television you need a UHF antenna, i.e. antenna with short elements. Or broadband.
Now you can evaluate whether your old antenna is suitable for receiving television in the DVB -T2 format. The only question that remains open is its serviceability and efficiency in your area.
In addition to dividing by received ranges, antennas are also divided into...
Indoor and outdoor (External) - I think everything is clear with the application here.
And also active and passive - more on that a little later.
Well, a brief excursion into the difficult topic of terrestrial antennas has been carried out. Let's continue...
Features of television signal propagation
The distance over which the signal is transmitted in the UHF range does not have a large coverage area. It is much less than in the meter range.
For example:
If you have used a radio, you may have noticed that you cannot catch distant foreign radio stations in the FM or VHF bands, but only those nearby, local ones.
But on the other hand, you can catch a whole bunch of foreign ones in the CB or HF bands.
This is because medium and short waves, like meter ones, propagate over long distances, and ultrashort waves, like UHF, over short distances.
This disadvantage of the UHF range for digital TV is compensated by the location and number of television transmitters - by analogy with cell towers, there are many of them.
Also keep in mind that the television signal is perfectly reflected from objects encountered along the way.
This allows you to receive broadcasts when it is not possible to point the antenna towards the TV tower. Or there are obstacles to the direct passage of the signal.
Look around! Is it possible to receive a reflected signal?
So if you choose the right antenna and install it correctly, you will surely achieve success.
What else should you consider when choosing an antenna?
The conditions for receiving a television signal are very different in different places and these conditions must be taken into account when choosing an antenna.
Here are some factors that will determine which antenna you need to purchase and how to install it.
- TV transmitter power and
- Terrain - mountains, lowlands, plains.
- Standing nearby and blocking the antenna in the direction of the tower are tall, dense trees.
- The presence of high-rise buildings and your location in relation to these buildings and the tower.
- The floor you live on - the higher you are, the simpler the antenna you will need.
- Possibility or impossibility of turning the antenna towards the transmitting tower.
Active and passive antennas - what is the difference?
Antennas of any type can be either active or passive.
Passive antennas are those that amplify the signal only due to their design, without the use of electronic amplifiers; such antennas are used in areas with a strong signal.
Active antenna - has an amplifier in its design; such an antenna needs to be connected to a power source.
The amplifier helps to increase the level of the received signal in areas of poor reception.
How to connect power to an active antenna amplifier, several ways
Antenna amplifiers are powered by 12 or 5 volts. But recently, more and more, manufacturers are focused on producing antennas with five-volt power supply.
And there is a reason for this! Such antennas are easier to connect for those who use a DVB-T2 set-top box.
Three connection methods
A) Use a special power supply with a separator that produces a voltage corresponding to your amplifier.
The purpose of a separator is to separate. It passes voltage to the antenna, but does not pass it to the TV socket. However, this does not interfere with the signal from the antenna amplifier entering the TV.
B) If a DVB-T2 set-top box is used. A voltage of 5 volts can be supplied directly from the set-top box. Moreover, for any amplifiers, both 5 and 12 volts.
This does not require any additional wire, power supply, etc. The voltage is 5 volts, from the antenna socket of the set-top box, directly through the antenna cable, it will go to the amplifier.
You just need to turn on this power directly from the set-top box menu. Go to the settings section and find the item “Antenna power ON-OFF”, select ON, and exit the menu (the names of these items may differ in different models of set-top boxes)
B) If you have an LCD TV with a built-in DVB-T2 tuner, then in addition to the method under letter A) you can do the following.
You will have to purchase a special adapter to power the amplifier from any USB port; first of all, consider the USB port of the LCD TV itself. But you can connect to any charger with a USB output
Which antenna to choose - let's look at examples
As you understand from all of the above, when choosing an antenna for yourself, you need to evaluate various factors.
A few examples:
Distance to the tower 5-15 km
You live in a city where there is a DVB-T2 signal transmitter. Or in a populated area, not far from the transmitter, 5-15 km.
Most likely, an indoor antenna, even the simplest one, will be suitable for you. Especially if you live above the first floor.
And being not far from the tower, even a simple piece of wire instead of an antenna may be enough.
Considering the prevalence of towers and a fairly large number of places with a reliable signal, scammers take advantage of this, offering various, essentially
Under the conditions described above, they will work well.
But keep in mind that the number of channels will not be more than that broadcast by the TV tower in your area! But not 100 or 200 as the advertisement promises.
Therefore, the question arises: is it necessary to shell out several hundred, or even thousands, for a regular indoor antenna from an advertisement?!
Here are several inexpensive, compact antenna options for conditions where there is a good signal.
Indoor antenna for places close to the tower. 
Indoor antenna for places close to the tower. Another option 
This option may work in slightly more difficult conditions than the previous two, especially the amplified version. Indoor antenna - application features
The right place for an indoor antenna is not where it will look good and stand comfortably, this is where it will receive the signal well. And these two circumstances - “look” and “accept” - do not always coincide.
Because often the best, and sometimes the only place where you can catch a signal is a place at the window facing the TV tower. Take this into account!
To solve this problem, you can add a cable of the required length, and for some antennas (for example, those in the photo above) this is not difficult.
But there are indoor antennas that have a built-in power supply in their housing. They also have a power cord for connecting to an outlet. And of course a cable for connecting to a TV.
This may seem convenient, but unfortunately it is not always the case.
Often, the place where the antenna is capable of receiving a TV signal is not near the TV and outlet, but, for example, near a window.
And in this case, a short power cord will become an obstacle to placing the antenna in the right place. In addition to the cable, you will also have to pull an extension cord. Basically a lot of wires.
You live at a distance of about 25-30 km or more from the TV tower.
Of course, a lot depends on the power of the transmitter.
But in general, at a distance of 25 km, a small outdoor antenna is sufficient. Like, for example, those depicted at the very beginning of this post, we mean the UHF antenna or the broadband “Hummingbird”.
In my area, from a distance of 25 km in line of sight, a passive UHF antenna with an arm length of approximately 80 cm provides reliable reception without the need to raise the antenna above two meters from the ground.
You can also receive reception using a good active indoor antenna.
In some houses, even from the first floor, if there is a window towards the tower or the ability to receive a reflected signal from neighboring buildings.
A floor above the second significantly increases the likelihood of success.
There is a simple principle on how to determine the power of an antenna - the longer the antenna arm, the greater the coefficient of its own gain, and not due to the amplifier.
Antenna for difficult signal reception conditions
For example, the active antenna in the photo below, in our area, pulls out a signal from a distance of 60 km or more. It is successfully used in the most difficult places, in houses located in deep lowlands, its length is approximately 1.7 meters, but there are antennas up to 4 meters in length.
In addition to the length, in difficult conditions or at a great distance from the TV tower, the presence of an amplifier plays an important role, i.e. the antenna must be active.
There are options for powerful antennas, where instead of one boom, three are used at once, so the ability of the antenna to amplify the signal due to the design alone is greatly increased.
And in tandem with an amplifier, this antenna becomes a very powerful trap for a television signal.
But once you’re impressed with this antenna, don’t rush to run after it. It is only needed under really, really difficult reception conditions.
In most cases, other, much cheaper options are sufficient. In addition, if the signal in your area is already strong, then the amplifier in the antenna will only interfere.
This is exactly the case when porridge can be ruined with butter. An example of this is described below.
Polish antenna array for digital television
In some cases, the “Grid” antenna can work quite successfully when receiving digital television. Especially if you are not very close to the transmitting tower.
More than once, however, I came across a situation where, using their old antenna - Polyachka (Grid), people could not get a digital broadcast signal from it.
Either at all, or the signal periodically “fell off”; the picture crumbled into cubes, and there was freezing of the image and sound. One of the digital television packages could disappear, while the other was working normally.
The problem with these phenomena is over-amplification of the signal.
There is a way out, let's consider the options...
1) Sometimes it’s just enough to unplug the antenna’s power supply from the outlet and that’s it. But this does not always help and then more serious measures are needed.
2) Reduce the amplifier supply voltage using an adjustable power supply. Or supply power directly from the set-top box, bypassing the separator of the standard antenna power supply, by installing a regular plug.
3) Get to the amplifier board, the board that is on the antenna itself, and connect everything without an amplifier.
4) Throw away this old dilapidated antenna and buy a normal UHF antenna.
P.S. New type grille.
I hope this article will be useful to someone, leave your reviews, comments, and share your experience.
P.S. If you are purchasing a new antenna, but are not sure whether it will suit you, ask your local antenna dealers.
Sometimes they are quite knowledgeable about which antenna is best to take based on your place of residence.
And agree on the possibility, if it suddenly doesn’t work, to change it to a different type of antenna. At least in my store this is possible.
Dear readers of the NskTarelka.ru blog, if you are interested in the answer to the question - Which antenna to choose for digital terrestrial TV? - then this article is just for you.
Before we start talking about choosing a television antenna for digital television of the DVB-T2 standard, let's talk a little about terrestrial television itself.
Terrestrial television - broadcast formats, signal broadcast
Free television channels, which we watch by receiving the signal on indoor or outdoor (street) antennas, are the same terrestrial television. A television (radio) signal is transmitted from a repeater into the air, that is, into the surrounding space, via electromagnetic waves. We, as users, use terrestrial antennas to receive this television signal.
To transmit a television signal, meter VHF (VHF) and decimeter UHF (UHF) waves are used.
Digital terrestrial television of the DVB-T2 standard is broadcast via UHF decimeter waves. Accordingly, in order to watch “digital” you need to have the “correct” antenna. It must be either all-wave (VHF + UHF) or UHF decimeter range. With an antenna that receives only VHF band, watching digital terrestrial television will not be possible.
MV and UHF are ultrashort wave (VHF) bands dedicated to the transmission of television signals. The frequency band is from 48 to 862 MHz, conditionally divided into 5 ranges combined into two groups:
- 1-12 channels meter or HF (VHF), bands I, II, III (47-160 MHz);
- 21-60 UHF channels, otherwise UHF (UHF), bands IV, V. (470-862 MHz).
Broadcasting of analogue terrestrial television occurs in both bands, both in HF and UHF. Previously, it was planned to turn off analog TV in Russia by the end of 2015, but now the deadline has been pushed back to 2018.
Which antenna to choose for digital TV?
Since we are choosing an antenna for digital TV, it is assumed that we have a DVB-T2 standard set-top box, or a TV with a built-in DVB-T2 tuner. We have accurate information that in the place we are interested in, where we want to enjoy watching digital television, it is already available.
Not that I’m “captain obvious” or as if for those who are “in the tank,” but you never know, just in case. Suddenly, someone reading is not in the know, and thinks that to watch digital television, the “necessary” antenna is enough. No, that's not true.
So, before you spend money on an antenna, let’s check what’s available. It is quite possible, just connect to the old antenna and everything will work.
If your antenna previously received analogue terrestrial television channels in the UHF range, then digital television will quite possibly work without problems. All you have to do is connect everything and scan the channels.
Why did I write quite possibly? Because there are some nuances. There are such concepts as the difference in altitude between your location and the available repeaters transmitting the television signal.
Collective antenna
First of all, if you live in an apartment building and it uses a collective antenna, try connecting through it. If everything works, great.
If not, contact your service organization with a request to sort out the television signal or install your own.
Indoor antenna
Whether an indoor antenna is enough for high-quality digital television reception depends on the distance of the repeater (transmitter), as well as its power. The power of the transmitter you are interested in can be found at the advisory support center.
Or, as an option, on the RTRS website, in the upper right corner, click on “Select region”, select your region (republic, region, district). After that, click on “Digital TV” in the menu. On the page that opens, click on the link “Digital broadcasting objects of the RTRS-1 package.” The table that opens will contain information about the transmitter power.
On average, the coverage radius of a DVB-T2 digital transmitter in the decimeter range, under the most ideal conditions (receiving antenna height 10 m, flat terrain, line of sight):
- 10 W - about 3 km.
— 50 W — about 5 km.
-100 W - about 15 km.
— 500 W — about 25 km.
-1 kW - about 30-35 km.
- 2 kW - about 35-40 km.
- 5 kW - about 40 - 50 km.
RTRS group VKontakte
When the TV tower is in direct view from the window, reception without an antenna is even possible. It is enough to connect a piece of coaxial cable, popularly called an antenna.
When connecting one TV, choosing between the options of a passive antenna or an active one, we give preference to the passive one. Passive is the one without an amplifier. Active with amplifier.
To broadcast the DVB-T2 standard to several TVs, an active antenna is purchased. Since the signal is split into two or more TVs using a divider, losses occur that are compensated by the amplifier. If there is a choice, purchase an antenna with adjustable signal gain. Thanks to this, we can control the signal amplification power.
The proposed selection of indoor antennas may give you a headache. Which one should I buy?
The upper price line is usually not good. Many expensive ones are not good at all.
There is no need to focus on those promoted as specialized for DVB-T2. Often this is beautiful junk for a lot of money. There are no specialized DVB-T2 antennas - this is a marketing ploy.
As I said above, the television signal broadcasts at frequencies of the meter - MV (VHF), and decimeter UHF (UHF) VHF ranges. The UHF range is currently allocated to the DVB-T2 digital terrestrial television standard. And the right one would be a UHF antenna, not a DVB-T2 antenna.
Therefore, if the box says super duper for DVB-T2, this does not mean anything.
If the TV tower is not visible from your window, but it is relatively nearby, it is advisable to purchase an indoor directional antenna. In this case, the signal comes to you reflected from other houses - an indoor directional antenna is the best option here.
In terms of price-quality ratio, an excellent option would be to purchase one of the brands - LOCUS (Locus) Moscow or Delta St. Petersburg.
If possible, before buying an indoor antenna, try to borrow it to test the signal from friends. Or if you buy in a specialized store, you may be able to negotiate a return with a replacement for a street one.
Outdoor (outdoor) antenna
When you can’t catch it with an indoor antenna or, due to the distance, it doesn’t even make sense to try, we use an outdoor (street) antenna. If there is an old one that is already on the roof or on the balcony, or outside the window, first we try to catch it. No antenna, let's go to the store.
What should you consider when choosing an outdoor (street) antenna? To begin with, using a map of the DVB-T2 digital television coverage area, we determine the distance from the antenna installation site to the repeater from which we plan to catch the signal.
When choosing an antenna, take into account the signal strength of the repeater. The power of a tower determines its reception area.
If the terrain is not flat, it makes sense to find out the difference in altitude between your location and the available repeaters transmitting the television signal.
When connecting one TV, as in the case of an indoor antenna, choosing a passive outdoor antenna is preferable to choosing an active one.
When distributing a signal to two or more TVs, we use an active antenna, i.e., with an amplifier. If there is a choice, we purchase it with adjustable gain.
When purchasing, we give preference to an antenna made only for the decimeter range - UHF (UHF). If you plan to watch analogue channels in parallel with digital ones, until they are turned off, purchase an all-wave one that supports both bands. Both meter - MV (VHF), and decimeter UHF (UHF).
In addition to choosing the antenna parameters, remember something equally important that needs to be taken into account during installation. We are talking about the height of the installed antenna. There are cases, and they are far from isolated, when even the most powerful antenna for signal reception will not help. But it is enough to raise the antenna height by a couple of meters, and it turns out that the old, less powerful one would be enough.
International standards for the area of reliable television reception are published based on the calculation of the height of the antenna:
For rural areas at least 10 m
- suburb, at least 20 m
- city 30 m
Therefore, the best solution for mounting the antenna is the highest point, i.e. the roof.
And at the end of the article, I bring to your attention a video from RTRS - How to set up an antenna for receiving digital terrestrial TV. Possible problems and ways to solve them.
In contact with
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 not changed much - in stores you can only find lightweight aluminum Chinese crafts, which do not show good results and rarely last more than a year. What to do if you like to watch TV, but there is no quality reception? 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.
You can create a homemade antenna for the digital range 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 such stations have one serious drawback - low power. And if in a big city the signal can often be caught even on a piece of copper wire, then far from the transmitter, reception may be difficult. 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 running 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 do not fit modern realities - the protective and directional coefficients today have virtually no effect on the 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.
Classic Polish antenna with amplifier 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. The ideal option is that 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 phase distortions appear when the amplitude-frequency response dips or jumps.
Attention: analog Antennas with ferrite USS, which provide full reception of the old signal, practically do not work with DVB. You need to build a “digital” antenna.
In the article we will analyze modern types of antennas that work with new digital broadcasting.
Antenna types
DIY antennas for digital TV Can you assemble it at home? There are three most common options:
- All-wave, or as radio amateurs call it, frequency-independent. It is assembled very quickly and 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.
- 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.
- 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.
Such connections are unacceptable - be sure to solder them 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 shaped accordingly 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, operates on the same principle. Aluminum cans are ideal in shape and size, creating vibrator arms in the decimeter range.
Two-can antenna for TV 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:
- 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).
- 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.
- The third piece is bent 90 degrees parallel to the first, length 14 cm.
- The fourth and fifth pieces are 13 cm each, the bend does not reach the loop by 2 cm.
- The sixth and seventh pieces are 14 cm each, bent at 90 degrees.
- 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.
You can assemble such an antenna in half an hour. 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.
