Homemade antennas: outdoor, home. Homemade antenna for digital television T2 Do-it-yourself digital television T2
Despite the rapid development of satellite and cable television, the reception of on-air broadcasting is still relevant, for example, for places of seasonal residence. It is not at all necessary to buy a finished product for this purpose; a home decimeter (UHF) antenna can be assembled by hand. Before proceeding to the consideration of designs, we will briefly describe why this particular range of the television signal was chosen.
Why DMV?
There are two good reasons to opt for this type of structure:
- The thing is that most channels are broadcast in this range, since the design of repeaters is simplified, and this makes it possible to set more unattended low-power transmitters and thereby expand the coverage area.
- This range is selected for broadcasting "numbers".
Indoor antenna for TV "Rhombus"
This simple, but at the same time, reliable design was one of the most common in the heyday of on-air television.
Rice. 1. The simplest homemade Z-antenna, known under the names: "Rhombus", "Square" and "People's Zigzag"As can be seen from the sketch (B Fig. 1), the device is a simplified version of the classic zigzag (Z-design). To increase the sensitivity, it is recommended to equip it with capacitive inserts ("1" and "2"), as well as a reflector ("A" in Fig. 1). If the signal level is acceptable, this is not necessary.
As a material, you can use aluminum, copper, as well as brass tubes or strips with a width of 10-15 mm. If you plan to install the structure on the street, then it is better to abandon aluminum, since it is susceptible to corrosion. Capacitive inserts are made of foil, tin or metal mesh. After installation, they are soldered along the contour.
The cable is laid as shown in the figure, namely: it did not have sharp bends and did not leave the limits of the side insert.
Decimeter antenna with amplifier
In places where a powerful relay tower is not located in relative proximity, you can raise the signal level to an acceptable value using an amplifier. Below is circuit diagram device that can be used with almost any antenna.
Rice. 2. Antenna amplifier circuit for the UHF range Item List:
- Resistors: R1 - 150 kOhm; R2 - 1 kOhm; R3 - 680 Ohm; R4 - 75 kOhm.
- Capacitors: C1 - 3.3 pF; C2 - 15 pF; C3 - 6800 pF; C4, C5, C6 - 100 pF.
- Transistors: VT1, VT2 - GT311D (can be replaced with: KT3101, KT3115 and KT3132).
Inductance: L1 - is a frameless coil with a diameter of 4 mm, wound copper wireØ 0.8 mm (it is necessary to make 2.5 turns); L2 and L3 are 25 µH and 100 µH high frequency chokes, respectively.
If the circuit is assembled correctly, we will get an amplifier with the following characteristics:
- bandwidth from 470 to 790 MHz;
- gain and noise coefficients - 30 and 3 dB, respectively;
- the value of the output and input resistance of the device corresponds to the RG6 cable - 75 Ohm;
- the device consumes about 12-14 mA.
Let's pay attention to the way the power is supplied, it is carried out directly through the cable.
This amplifier can work with the simplest designs made from improvised means.
Indoor antenna made from beer cans
Despite the unusual design, it is quite functional, since it is a classic dipole, especially since the dimensions of a standard can are perfect for the arms of a UHF vibrator. If the device is installed in a room, then in this case it is not even necessary to coordinate with the cable, provided that it is not longer than two meters.
Designations:
- A - two cans with a volume of 500 mg (if you take tin, not aluminum, you can solder the cable, and not use self-tapping screws).
- B - places for fastening the shielding braid of the cable.
- C - central vein.
- D - the place of attachment of the central core
- E - cable coming from the TV.
The arms of this exotic dipole must be mounted on a holder made of any insulating material. As such, you can use improvised things, for example, a plastic clothes hanger, a mop bar, or a piece of wooden beam of the appropriate size. The distance between the shoulders is from 1 to 8 cm (selected empirically).
The main advantages of the design are fast production (10 - 20 minutes) and quite acceptable quality of the "picture", provided that the signal strength is sufficient.
Making a copper wire antenna
There is a design that is much simpler than the previous version, for which only a piece is required copper wire. This is a narrow band loop antenna. This solution has undeniable advantages, since in addition to its main purpose, the device plays the role of a selective filter that reduces interference, which allows you to confidently receive a signal.
Fig.4. A simple UHF loop antenna for receiving digital TV For this design, it is necessary to calculate the length of the loop, to do this, you need to find out the frequency of the “numbers” for your region. For example, in St. Petersburg it is broadcast on 586 and 666 MHz. The calculation formula will be as follows: L R = 300/f, where L R is the length of the loop (the result is presented in meters), and f is the average frequency range, for Peter this would be 626 (the sum of 586 and 666 divided by 2). Now we calculate L R, 300/626 = 0.48, which means that the length of the loop should be 48 centimeters.
If you take a thick RG-6 cable, where there is a braided foil, then it can be used instead of copper wire to make a loop.
Now we will tell you how the structure is assembled:
- A piece of copper wire (or RG6 cable) is measured and cut off with a length equal to L R .
- A loop of a suitable diameter is folded, after which a cable is soldered to its ends, which goes to the receiver. If RG6 is used instead of copper wire, then the insulation is first removed from its ends, by about 1-1.5 cm (the central core does not need to be cleaned, it does not participate in the process).
- The loop is installed on the stand.
- An F connector (plug) is screwed onto the cable to the receiver.
Note that despite the simplicity of the design, it is most effective for receiving "numbers", provided that the calculations are carried out correctly.
Do-it-yourself indoor antenna MV and UHF
If, in addition to UHF, there is a desire to receive MV, you can assemble a simple multiwave oven, its drawing with dimensions is presented below.
To amplify the signal in this design, a ready-made SWA 9 block is used, if there are problems with its acquisition, you can use homemade device, the scheme of which was given above (see Fig. 2).
It is important to observe the angle between the petals, going beyond the specified range significantly affects the quality of the "picture".
Despite the fact that such a device is much simpler than a log-periodic design with a wave channel, nevertheless, it shows good results if the signal is of sufficient power.
Do-it-yourself figure-eight antenna for digital TV
Consider another common design option for receiving "numbers". It is based on classical scheme for the UHF range, due to its shape, called the "Eight" or "Zigzag".
Rice. 6. Sketch and implementation of the digital eight Construction dimensions:
- the outer sides of the rhombus (A) - 140 mm;
- inner sides (B) - 130 mm;
- distance to the reflector (C) - from 110 to 130 mm;
- width (D) - 300 mm;
- step between the bars (E) - from 8 to 25 mm.
The cable connection point is at points 1 and 2. The requirements for the material are the same as for the Rhombus design, which was described at the beginning of the article.
Homemade antenna for DBT T2
Actually, all the examples listed above are capable of receiving DBT T2, but for a change, we will give a sketch of another design, popularly called the “Butterfly”.
As a material, you can use plates made of copper, brass, aluminum or duralumin. If the structure is planned to be installed on the street, then the last two options are not suitable.
Outcome: which option to stop?
Oddly enough, but the simplest option is the most effective, so the "loop" is best suited for receiving the "digit" (Fig. 4). But, if you need to receive other channels in the decimeter range, then it is better to stop at the "Zigzag" (Fig. 6).
The antenna for the TV should be directed towards the nearest active repeater, to select the desired position, rotate the structure until the signal strength is satisfactory.
If, despite the presence of an amplifier and a reflector, the quality of the "picture" leaves much to be desired, you can try to install the structure on the mast.
In this case, it is necessary to install lightning protection, but this is a topic for another article.
Digital terrestrial television(DVB-Digital Video Broadcasting) is a technology for transmitting television images and sound using digital video and sound coding. Digital encoding, unlike analog, provides signal delivery with minimal losses, since the signal is not affected by external interference. At the time of writing, 20 digital channels are available, in the future this number should increase. This number of digital channels is not available in all regions, learn more about the ability to catch digital channels you can visit www.rtrs.rf. If there are digital channels in your area, in this case, it remains to make sure that your TV supports DVB-T2 technology (this can be found in the documentation for the TV) or buy a DVB-T2 set-top box and connect the antenna. The question arises - What antenna to use for digital TV? or How to make an antenna for digital television? In this article, I would like to dwell in more detail on antennas for viewing digital television, and in particular, I will show how to make a digital tv antenna.
The first thing I would like to emphasize is that digital television does not need a specialized antenna, it is quite suitable analog antenna(the one you used earlier to watch analog channels). Moreover, only a television cable can be used as an antenna ...
In my opinion, the simplest antenna for digital television is a television cable. Everything is extremely simple, a coaxial cable is taken, an F connector and an adapter for connecting to a TV are put on one end, and the central core of the cable is exposed at the other end (a kind of whip antenna). It remains only to decide how many centimeters to expose the central core, since the quality of reception of digital channels depends on this. To do this, you need to understand at what frequency digital channels broadcast in your region, to do this, go to the website www.rtrs.rf/when/ here on the map, find the tower closest to you and see how often digital channels broadcast.
More detailed information you will get if you click the "More Info" button.
Now we need to calculate the wavelength. The formula is very simple:
where, λ (lamda) - wavelength,
c - speed of light (3-10 8 m/s)
F - frequency in hertz
or easier λ=300/F (MHz)
In my case, the frequency is used 602 MHz and 610 MHz, for the calculation I will use the frequency 602 MHz
Total: 300/602 ≈ 0.5 m = 50 cm.
Leave half a meter of the central core coaxial cable it is not beautiful and inconvenient, so I will leave half, maybe a quarter of the wavelength.
l=λ*k/2
where l is the length of the antenna (central core)
λ- wavelength (calculated earlier)
k - shortening coefficient, since the length of the entire cable will not be large, this value can be considered equal to 1.
As a result, l=50/2=25 cm.
From these calculations, it turned out that for a frequency of 602 MHz, I need to strip 25 cm of coaxial cable.
Here is the result of the work done
Here is what the antenna looks like when installed.
View of the antenna while watching TV.
If you live in the city, then you do not need to have a large and bulky TV antenna, much less throw it on the roof and pull the cable. Digital television channels of the DVB-T2 standard can be perfectly received in the room, since the power of the transmitting towers is quite enough for confident reception. I'll show you how to make a miniature biquadrat home antenna in 15 minutes. I also call it the Kharchenko antenna. This master class will save you from buying expensive Chinese counterparts.
Typically, the calculation of such structures is carried out at 1/4 wavelength. Such an antenna will well receive all channels even outside the city at a considerable distance, but at home (in the city) its dimensions may seem a bit large. And actually such sensitivity will be nothing. You can reduce all dimensions by half and take 1/8 of the wavelength as a calculation. The current antenna will be very tiny, but with sufficient sensitivity.
It will take
Making a miniature home antenna for digital television
The antenna circuit itself. This is perhaps the simplest and most common option, and we will make it even smaller.
We take the wire and, without removing the insulation, bend two identical squares with sides of 67 mm with pliers.
We solder the connected ends and clean off a little insulation from the middle and tin.
Then, on small wires, solder the socket. In the lid with a clerical knife we will make cuts under the shoulders of the vibrators.
Fill everything with hot glue.
In the second cover, we drill a hole for the nest and also glue it with hot glue. We connect the covers and solder them with a soldering iron so that there is one whole. The antenna is ready.
Everything fits in the palm of your hand, therefore, with the question “Where to place it?” there shouldn't be any problems.
The result of the work
We connect and send to the tower.
I will compare the antenna with the same one, only full-sized at 1/4 wavelength.
A Chinese set-top box for receiving digital television will serve as a level sensor.
Result:
- Kharchenko's classic antenna 1/4 wavelength, the prefix gave out - 40% sensitivity.
- Our reduced version of 1/8 wavelength - 22% .
- And for comparison, let's stick a regular piece of wire - 1% .
At home, the antenna proved to be excellent. All channels are caught and received steadily, just like on the full-size version. Recommended for repetition. How to make a T2 antenna with your own hands or from an old antenna
Below is a "butterfly antenna". Which is used by your obedient servant. It is made of copper, absolutely no amplifiers! Antenna, cable, TV. Hangs inside the balcony and gives an excellent uninterrupted signal. I also sat quietly on such an antenna as in the video above. For Ukraine, the length is 13 cm, for Russia, 14 cm. I cleaned even to the wire, but it quickly oxidizes. Generally shows.
God help you.
Modernization of the "Polish" antenna under T2
You can use the "Polish" antenna as a whole assembly with an amplifier without alteration, but as experience shows, some frequency channels have a weak signal level.
Here we are all surprised at the versatility of the "Polish" antenna, and the Polish antenna is nothing more than the simplest combination of the simplest universal "butterfly" antenna, widely known since the 60s, with a vibrator length of 1150 mm and an opening angle of 38 ° for reception from 1 to 12 th channel in line of sight conditions
And a primitively designed "antenna wave channel" and not a single size fits into any calculations and GOSTs. That is, we have an ordinary, practically, dummy UHF antenna in a "Polish" antenna for receiving UHF (I'm talking about directors-passive selectors). It turns out that only a "butterfly" works in this antenna, or rather several "butterflies" are active selectors, and I also note those designed for a certain range (they are all the same length), and SWA Amplifier.
If you remove the SWA amplifier, then the antenna will not work. I lead to what it is enough to bend such an active vibrator of a certain size (we will talk about this below), connect the SWA amplifier. get much better "Polish"
ATTENTION: the cable is routed along the arm of the active vibrator, which is connected to the “case” of the amplifier circuit! At the midpoint of the vibrator, where the RF potential is equal to zero, the cable is smoothly bent and directed along the traverse, then - to decrease.
In short, any homemade antenna + SWA amplifier works much better than any "Polish".
But what we already have is what we have. Let's try to bring it a little into a normal DMV look. "Meter" mustaches (long active vibrators, see fig. 1) are absolutely not needed, if we use an antenna for T2 (UHF wave range), you can cut them to the same length with decimeter active vibrators. If one of the received channels is weaker than the others, it is necessary to try to remove the reflector sheet from the active vibrators. With this adjustment of the antenna, its output impedance increases and changes frequency response. Changing the antenna impedance does no harm at all, since the input impedance of the amplifier is higher than the antenna impedance. Radio amateurs with experience with antenna amplifiers, can drop matching-balancing elements on a ferrite ring from the amplifier circuit, this will expand the range of operation of the active antenna. One of the input terminals of the antenna is connected to the input of the amplifier, and the second - to the "case" of the amplifier circuit.
Antenna resistance at equal received power is related to the output voltage
P=U2/R. U=(P*R)½.
From this follows the conclusion - it is necessary to increase the output impedance of the antenna (the input impedance of the amplifier is greater than the resistance of the antenna). With success, you can use antennas with an impedance above 300 ohms. This connection method is also suitable for a wide-range antenna of the "wave channel" type (more on this later), and in a log-periodic antenna, the output cable is symmetric, passing through the antenna element (according to the principle of Fig. 2).
Something I have a lot of abstruse quirks, you still think that I'm smart already .... yes, no, everything is simple - Would you google with mine
I'll try to keep it simple
I do not advise cutting "long mustaches" if you do it for yourself, if you are lazy or for "uncle" I advise you to shorten it with the calculation L (vibrator length) = 1/2j (half the average length of a weak frequency channel)
And for ourselves, we bend two rhombuses and remove the reflector from the back of the rhombuses, or insert the bushing into the mount and bend it 10 cm
Now let's conjure with the directors. I already mentioned the "wave channel" antenna, this is a miracle known from the time of black and white TV
So let's take the dimensions of the directors and the distances between them with the "grandfather" antenna tested over the years.
Attention Critical here is the distance from the active vibrator "two rhombuses" or "butterfly" (cut off long mustaches) as someone did, also for other "butterflies" to the first director (unless of course there is a desire to change wires (tubes), here segments from long mustache
The last figure shows the sizes and distances for the frequencies of the channels in the band 21 ... 41. For the remaining frequency channels, the sizes can be calculated using the Antwu15 program
So, let's start with the program. With its help, you can calculate various options for antennas tuned to different ranges. We launch. We are only interested in the first point.
Everything is simple. We enter the data for which the antenna will be tuned, and the program will do everything itself.
For example:
The center frequency of the antenna refers to the broadcast frequency of the last 61-69 channels. The number of elements determines the length of the traverse. We set the diameter of the elements 1-5 (not so significant).
Way of fastening of elements - through a traverse. We agree, and as a result we get the finished dimensions for our product.
Below is the result obtained, according to which one of the variants of the UHF antenna was made. This option provides a stable reception of a signal from a tower 80 km distant through splitters for two TVs and a PCI-TV tuner in a computer.
It remains only to collect. The length of the antenna is determined by the number of elements
I advise you to put directors for one frequency range on each "butterfly" (they will all be the same length) - four "butterflies" correspond to four frequency channels of Ukraine
Here is another table of director lengths for a universal log-periodic antenna (counting from the "butterfly") from 21 .... 64
vibrator no. length in mm distance in mm
7…………………………..107...............0
6…………………………..129..............80
5…………………………..155..............94
4…………………………..186..............77
3…………………………..225..............63
2…………………………..272..............53
1…………………………..330...............43
0.......................................
Do-it-yourself simple UHF TV antenna
1. Ring-coaxial cable PK75, 530mm long.
2. Loop-coaxial cable PK75, 175mm long.
3. To the console.
Assembly:
To assemble this antenna, you do not even have to run around the shops.
To do this, you need to take the PK75 antenna cable 530mm long (for the ring) and 175mm. (for loop).
Connect as shown in the picture.
Fasten to a sheet of plywood (plexiglass) using wire ties.
Direct to telecentre.
Here you have a UHF antenna that will work no worse than a purchased one.
And if you still go to the market or to the store, buy an SWA amplifier (we put the SWA amplifier instead of a loop) and a power supply unit for it (40 UAH), then it’s even better to buy it.
Do-it-yourself television antenna DMV "Narodnaya"
The antenna is an aluminum disk with an outer diameter of 356mm and an inner diameter of 170mm. and 1mm thick., in which a 10mm wide cut was made.
A printed circuit board made of fiberglass 1 mm thick is installed in place of the cut. This board has two holes for fixing with M3 screws.
TO printed circuit board attached to the antenna, solder the leads of the matching transformer T1.
For a transformer, it is best to use a ring core with an outer diameter of 6 ... 10 mm., An inner diameter of 3 ... 7 mm. and 2…3 mm thick.
The transformer windings are superimposed with a single-layer insulated wire with a diameter of 0.2 ... 0.25 mm. and have the same number of turns, from 2 to 3 turns. The length of the turns of the turns is 20mm.
In the presence of such a transformer, reception is possible in the meter and decimeter range at a distance of 25 ... 30 km. At a distance of up to 50 km. the antenna works satisfactorily only on UHF channels.
Without a transformer, the reliable reception distance is halved.
However, there is a circuit that allows you to get similar results without a transformer, for this you need to assemble the following circuit:
Here you can also use an SWA amplifier (we put an SWA amplifier instead of a transformer) and a power supply unit to it. But as experience shows, it is better to use a transformer to which we supply power to the power supply unit from the "Polish"
UHF television antenna with a simple do-it-yourself reflector
Taking this antenna as a basis, I bent a big mustache on the "Polish"
1. aluminum strip frame
2.amplifier
3. mast
4. reflector
A. Braid Solder Point
B. central conductor soldering point
Assembly:
1. First, a frame is assembled from aluminum plates, overlapping, as shown in the figure, with the help of bolts (after fastening, the fastening points should be painted with paint to avoid oxidation).
2. Further, a coaxial cable is soldered at points A and B.
3. bolt the frame to the mast
4. make from rods with a diameter of 3 ... 10 mm. (Or you can just a reflector from a collapsed polish or fittings for wall ticking), attaching the reflector to the mast with brackets
5. fix the amplifier on the mast, bring the coaxial cable to it.
Assembly is possible without a reflector, however, the gain of such an antenna will be lower.
Do-it-yourself television antenna UHF with a complex reflector
1. a frame made of aluminum strips (a reflector from a collapsed polish or fittings for wall ticking)
2.amplifier
3. mast
4. reflector
Assembly:
1. First of all, a frame is assembled, from aluminum plates, as for a simple reflector
2. Next, a reflector of the "dilapidated box" type is assembled as shown in the figure (The design of such a reflector can be very different, it all depends on your capabilities).
3. the reflector is attached to the mast on metal brackets
3. then the amplifier is attached to the mast, and the coaxial cable is soldered, too, as with a simple reflector
On decimeter waves in the range of 470-638 MHz (channels 21-41), directional antennas can be used as indoor antennas, since their dimensions at these waves are relatively small. As directional indoor antennas of decimeter waves, antennas of the “wave channel” type are most convenient.
Figure 1 shows appearance room antenna of decimeter waves ATCD-2 of the "wave channel" type, operating without tuning on channels from 21 to 41 in the range of 470-638 MHz. The geometric dimensions of the antenna are shown in Fig. 2a. The antenna consists of a base with a stand and a removable antenna sheet. The antenna sheet contains an active vibrator 1, a reflector 2 and two directors 3 and 4, which are made of brass or steel tape and attached to a plastic boom.
Drop cable 5 is connected to the antenna through a short-circuited balancing bridge (Fig. 2b), the length of which is equal to a quarter of the wavelength at the middle frequency of the 470-638 MHz range. The bridge is formed by a two-wire line, one conductor of which is the metal screen of the drop cable, the second is section 6 of the MGShV mounting wire with a cross section of 0.35 mm2. At a distance of 140 mm from the antenna input terminals, equal to the required length of the bridge (a quarter of a wavelength at a frequency of 550 MHz), the mounting wire is soldered to the cable shield. The gain relative to the half-wave vibrator is not less than 5.5 dB.
Here is another version of the bending of the "long mustache" of the Polish antenna and the replacement of directors (for the range of 42 ... 64 length and distance we calculate the program)
Do-it-yourself high-quality MV-UHF antenna "wave channel"
OUR FRIEND: https://forum-t2.com/
Unofficial support for T2 digital television users
This type of antenna belongs to purposeful UHF antennas.
Since the gain of the purposeful UHF antenna is better than that of the Polish array, it was decided to make a "hybrid" from the old domestic UHF antenna and the ASP-8 Polish array with its amplifier. Happened! The image quality of the weak improved markedly. The idea of \u200b\u200bmanufacturing was proposed somewhere by someone, it only remained to implement it.
I will tell simply, without any abstruse expressions and formulas.
For self-manufacturing antenna needed:
Special program for calculating Antwu15;
1 or 2 amplifiers from the grid (with cases);
Aluminum pipe section? o 25mm and length? 2m. (traverse);
3 aluminum tubes with a cross section of up to o10mm, two lengths of? 1m. (MV) and more? 2.5-3m. (for cutting UHF elements);
2 sheets of textolite 3-5 mm thick, dimensions: 300mmx150mm (for mounting MV);
You will also need self-tapping screws (? 20 pcs. 15 mm) and bolts with nuts (thread x3 6 pcs. 20 mm) (for fastening DMV and MV elements);
How to use the program we discussed above in Modernization of the "Polish" antenna under T2
We get the dimensions calculated by the program. It remains only to assemble. The length of the antenna is determined by the number of elements, you can calculate 1.4m, but the gain will be less. In general, the choice is yours.
To obtain better shielding from the reflected signal, the role of a reflector can be performed by a grating-screen from the ASP-8 "Polish" antenna, dimensions: long - as in the calculation of the program, height 300 mm. Curved edges point forward. You can also use other material in the form of sheet iron, aluminum, or use old UHF antennas.
Now we are preparing an MV antenna from two meter vibrators. It's much easier here. Its role will be played by 2 tubes with a cross section of 10 mm and a length of 1 m, folded at an unfinished angle of 120 degrees. This part of the antenna can not be assembled if we collect strictly meter waves for T2. And what do we have for the antenna?
Here is a sketch of the resulting "monster":
Before us is the well-known .... "crow", which was used by our fathers and grandfathers from the 60s, looking through the lens of black and white TV. So, it’s not necessary to throw 100 UAH into the wind - half a day of effort and forty hryvnia
Well, back to my "sheep" - we'll finish assembling the antenna.
Next we take the traverse. We make its length 5 cm longer for mounting the MV antenna. The traverse is an aluminum tube with a sec. 25mm. and make notches on it at the points of attachment of the elements, the loop vibrator and the reflector. Distance, according to the calculated table. We drill 10mm holes through them at a right angle, and insert elements into them. Elements can be attached different ways: using self-tapping screws from above, cutting threads in the elements with bolts or, putting rubber tubes on the elements, firmly insert them into the holes of the traverse.
The heart of the antenna is a loop vibrator, which can be made from a 13mm wide aluminum plate, or a 10mm aluminum or copper tube.
The size of the loop vibrator is selected empirically, already on the assembled antenna.
The loop is not needed, instead we use an amplifier from the "Polish" antenna. We fasten its body with bolts into the holes of the vibrator.
Attention And now we are furnishing the “crow”, we don’t put a long mustache - this is a meter-long part of the antenna, we put a reflector from the “Polish woman” and bend it in this way like a UHF antenna with a complex reflector
We fasten the antenna to the mast well, install the mast - preferably higher, direct it and the "crow" is resting. Good luck
Do-it-yourself television log-periodic antenna of the UHF range
To make a web, the tubes of two hoops should be unbent, and then bent according to the given template and both halves of fig.
On the tubes at the bends, notches should first be made (after about 200 mm). The antenna can be attached to the mast with getinax plates or wooden blocks (three are enough). The cable is laid along the canvas in accordance with the upper figure.
To protect against corrosion, the soldering points and the joints of the strips with the canvas are smeared several times with BF glue (such protection is enough for several years). The braid must be soldered to the strip of that half of the antenna along which the cable is laid. To get the maximum signal, you need to add a reflector from metal strips (screw directly to the mast with screws). The distance between the antenna web and the reflector is selected according to the best image (110 ... 160 mm). The dimensions are given in accordance with the setting for the 30th channel fig.
Well, if there is no desire to steam, we make a transformer as in the "folk" or put an SWA amplifier.
However, due to the wide band, the antenna receives signals well in the range from the 21st to the 40th channel. Such an antenna, even without a reflector, gave better results than a 16-element wave channel, all other things being equal. As you can see, this antenna is more powerful for the "butterfly" and "wave channel" and, as I said in the "Polish" antenna of the director, this is a dummy, that's we throw out all the "butterflies" and from an aluminum wire with a diameter of 6 mm we bend two halves of semi-diamonds according to the template, inserting them into the mounts instead of butterflies. Well, we move the reflector to the desired distance (here's another option for upgrading the "Polish")
Added after 53 minutes 13 seconds:
Do-it-yourself universal car television antenna
All-wave car television antenna with a circular radiation pattern in the horizontal plane. This antenna can also be used in stationary conditions, i.e. not only on a car, but also for home TV. You can also take the modernization of the "Polish" antenna as a basis - bend the "long mustache" with a ring of a certain diameter, or rather bend it like this, connecting with a neighbor's butterfly - this is one mustache, and the second bend as in indoor antenna decimeter waves "wave channel" active loop vibrator for example (I remind you, we take the size of 1/2 wavelength of a poorly showing range)
car television antenna consists of
1. 2 aluminum rings (d=270mm and d=130mm)
2. wooden rail (3x3cm.)
3. TV cable
Assembling a car television antenna
Such an antenna can be built using a commercially available 300/75 ohm plug (see figure) with a matching transformer inside it for imported TVs.
Two aluminum rings are attached to the plug using the screws on it: one with a diameter of 270 mm for the MV band (channels 6-12), the other with a diameter of 130 mm for the UHF band (channels 23-51). Since the MV ring does not suit us (we need a channel range of another 51 ... 64), we change it to a calculated diameter of 90 mm. The antenna made in this way is attached to a wooden rail with a cross section of 3x3 cm with a hole for the plug plug. The plug is attached to the rail with electrical tape, and the rings are fixed with two insulators to stiffen the system. The rail is bolted to the trunk frame located on the roof of the car. Using a typical industrial cable (plug-socket) RK-75-4-11, the antenna is connected in the rear of the car to the car TV.
The antenna can be equipped with an amplifier (SWA-7 or SWA-9) powered by the vehicle battery to increase efficiency.
Added after 1 hour 48 minutes 11 seconds:
Do-it-yourself universal "can" television antenna of the UHF range
The proposed antenna uses improvised materials. But, nevertheless, it works in the entire range of TV UHF, and is not inferior in terms of parameters to a standard six-element log-periodic antenna, which is commercially available.
To make this antenna, you will need two empty cans with a diameter of 7.5 cm, a length of 9.5 cm and two small strips of filtered fiberglass.
The cans are connected with strips of fiberglass using soldering. The upper strip is solid, and the foil on the bottom is cut, (as shown in the figure)
for connecting a 75-ohm power cable.
The total length of the antenna for operation in all UHF channels must be at least 25 cm.
This antenna is something like a symmetrical broadband vibrator. Due to the large surface area, it has a high gain. When using cans of small diameter, it is necessary to cut the foil in the upper strip.
Added after 16 minutes 44 seconds:
Do-it-yourself frame television antenna UHF range
This antenna has a high gain and can be used both indoors and outdoors. Differs in ease of manufacture, availability of materials, small size, aesthetic appearance.
The design of the antenna is shown in the figure, the dimensions are in the table:
Based on a three-loop antenna. For the manufacture of the antenna, any wire made of copper, brass, steel, aluminum, etc. with a diameter of 3 ... 8 mm is taken and bent according to the pattern. At the joints, the wires are soldered. Antenna cable soldered to points A and B. At point C, the cable sheath is connected to the antenna material.
It is possible to take this antenna as the basis for the modernization of the "Polish" antenna - bending a long mustache in the form of an average square, taking into account that B (Polish) \u003d 1 / 2B (frame)
Tags: How to make an antenna, T2, with your own hands, or, from, an old, antenna, quickly, simply, free of charge, antenna t 2, russia, ukraine
| Updated 15 Jan 2018. Created 29 Feb 2016 | |||||||||
The era of broadcasting analog signals on television is over. Modern scientific developments completely replace old technologies.
People, when purchasing new equipment, are forced to make antennas for digital television with their own hands in various ways or buy ready-made industrial designs.
I want to draw your attention to the fact that antennas for DVB T2 digital TV are not at all difficult to make on your own. I specifically tested four schemes that take into account the different living conditions of people. I present them to you for your reference. See my photos and available assembly drawings.
How does a digital TV antenna work: I explain simply
Before you start assembling any of the four models of receiving antennas, you should have a good understanding of the processes that should take place in them.
Electromagnetic waves propagate in all directions of the horizon from the generator of the transmitter of electrical signals installed on the TV tower.
They have coverage for their area, but with increasing distance, their signal weakens. Its magnitude is also affected by the terrain, various electrical and magnetic obstacles, and the state of the atmosphere.
In a vibrator oriented perpendicular to the movement of an electromagnetic wave, according to the laws of induction. The positive and negative half-wave of the harmonic create their own sign.
The voltage reaches its maximum value - the amplitude at the points of time corresponding to ¼ and ¾ of the period or 90 and 270 degrees from the sinusoid of the electromagnetic wave strength.
Any shape and size of active vibrators is created for the most efficient voltage induction with minimal energy loss. Accounting for the position of these points is calculated from the wavelength or harmonic frequency.
The voltage, closed to, generates in the created circuit. Its shape and direction change and proportionally repeat the signals of the transmitter on the active load.
Due to the use of various types of digital modulation on the transmitter side, information signals are received and processed inside the television receiver circuit.
I will not go further to consider the question of how a digital antenna for a TV works when it is created.
What technical characteristics of the antenna determine the quality of TV signal reception
The antenna is classified as a reversible device because it works the same way on the transmitter and receiver sides. When analyzing the characteristics, its inclusion as a generator is used.
For effective reception of a digital signal, it is necessary to take into account that on the side of the generator, the emitter of electromagnetic waves can be placed at any angle to the horizon, but only two directions are legally accepted: horizontal and vertical.
Our task is to repeat this orientation for our own TV.
Direction of polarization and other transmission data digital signals can be found on the operator's website through a search engine.
We go to the site, select the necessary information.
We are primarily interested in 3 characteristics:
- channel number and its frequency, for which we will create an antenna according to strict dimensions;
- the radius of the transmitter coverage area, which affects the signal quality and the choice of vibrator design;
- polarization direction.
The distance of the TV from the transmitting TV tower greatly affects the design of the antenna.
The higher the antenna is installed, the better the quality of the received signal will be, but the length of the cable can significantly weaken it. In this regard, residents of the upper floors of multi-storey buildings have a significant advantage over their neighbors below.
For the zone of reliable reception, I tested the simplest Kharchenko models and loop assemblies made of coaxial cable and wire, which have a wide range of reception frequencies.
For long distances, it is better to collect a wave channel or a log-periodic scheme. Of the simple designs, the Turkin antenna, modified by Polyakov, has proven itself well.
For example, in my area, the distance from the TV tower was 25 km, which is included in the zone of reliable reception, and the signal frequency was 626 MHz of vertical polarization.
I calculate the length of the electromagnetic wave through the speed of light in frequency: λ=300/626=0.48 meters. A half wave will be 24 cm, and a quarter - 12.
Under these characteristics, I made 4 test antennas for digital television with my own hands, which I describe below.
Antenna Kharchenko for digital TV: how confident it works
I show a general view of the structure I assembled with a photograph. Given the vertical polarization, it is located in the shape of a figure eight, and for the horizontal orientation it is rotated like a butterfly.
For clarity of consideration, he turned it over with its reverse side: with a screen to the transmitting center, and with an active vibrator made of a copper bar - into the room.
The TV cable is simply taped on one side of the square with electrical tape, fixed on the stand and in my case also serves as a fastener: it is simply thrown over the curtain rod: an antenna hangs on it.
My design has already been repeated by many neighbors. I see it like this window design.
People hang the figure eight even on curtains, they began to make it without a screen and a mounting rail: one active vibrator confidently provides reception. This simplifies assembly. However, in the event of the appearance of extraneous interference, I advise you to collect the screen.
I conclude that the Kharchenko antenna in the zone of reliable reception works quite reliably. Since its calculation and installation is simple, it does not require scarce parts, I recommend it for assembly.
How to calculate the dimensions of an antenna for digital television with your own hands in simple ways
To determine the dimensions of Kharchenko's structure, I found many recommendations that, to put it mildly, do not fit together, but work. In the picture I give only 3 methods of calculation.
There are also online calculators that calculate different sizes. I explain all this by the fact that such a design is not critical to manufacturing accuracy, which I consider to be its advantage.
For verification, I chose the technique where the side of the square is 0.25 of the wavelength of the electromagnetic oscillation λ. Here you need less material, and the working conditions are the most complicated.
I multiply the wavelength 48 by 0.25 and get the side of the square 12 cm.
Then it will capture a slightly larger range of signals due to the fact that such a form of the vibrator processes all the amplitudes of half-waves of tension that fit inside it. Due to this, its broadband is ensured.
How to make a Kharchenko antenna: personal experience of "assembly on the knee" with photos
An active vibrator was made from a copper bar of rectangular section 1x4 mm.
Such a profile is difficult to bend. You have to work under pressure. It is easier to work with a round section. I cleaned the middle part of the varnish and soldered the contact pads with a soldering iron.
On one side of the square, I wound a coaxial cable with electrical tape and soldered its current-carrying wires to the prepared sites.
Due to the created half-loop, an angle of matching of the wave impedances of the cable and antenna is formed. This is the simplest design to implement. But she plays an important role.
I show this connection with additional photos on the finished antenna.
Marked out a wooden rail, drilled thin holes in it.
I inserted pieces of wire into them, the length of which slightly covers the area of \u200b\u200bthe active vibrator, wedged them with matches. You can also add glue.
It turned out such a Kharchenko antenna for digital TV with a cable connected to it.
Here I show its location on the window during work last summer.
And I took this picture recently: I show another view of it.
At this time, I had already abandoned the use of an antenna for digital TV DVB T2 after Beltelecom Yasna.
Antenna for digital TV from cable: how to quickly make
To assemble this circuit, you only need a piece of coaxial TV cable about a meter long, a knife, a soldering iron, although you can do without it.
The loop works in the zone of reliable reception, has good performance even inside a dense building of multi-storey buildings made of reinforced concrete slabs. Since a fairly simple assembly took me about 5 minutes of time, it can be checked at least for the sake of curiosity.
I explain the technology of installation.
The size of the circumference of the assembled loop corresponds to the wavelength of the electromagnetic oscillation. I have, as shown above, it is 48 cm.
I cut one end of the coaxial cable at a distance of about 5 centimeters. For clarity, I put a matchbox next to it with standard dimensions 3x5.
From the beginning of the cut, I measured the half-wave distance: 24 centimeters. Next, you need to make a section where the shielding braid will be broken.
We make its distance 2 cm. On this segment, carefully check the absence of wires and electrical connections. Only the polyethylene insulation of the central core should be visible.
Then, along the length of the cable from the created gap, I measure another 24 cm and remove the upper protective sheath made of polyethylene along a ring 1 centimeter wide.
You have to work carefully. The shield braid and its electrical connections must be preserved.
I show this area in close-up.
Now there is just a little left: I check the absence of corrosion on the stripped braids, tightly twist the conductive screen with the central core between my fingers. They need to be short-circuited.
A twisted end is formed about 5 centimeters long. It remains to wrap it tightly around an open section of insulation 1 cm wide. The loop is ready.
On the reverse side of the cable, a plug is soldered for connection to the TV socket. I omit this trivial operation. There are no difficulties in it.
An antenna for digital TV from a cable with its loop plane is oriented perpendicular to the direction of the transmitting station.
On a positive note: the material of the loop is made of the same material as the subsequent feeder for connecting to the TV. They have the same wave impedance. Nothing needs to be agreed upon.
Antenna made of wire: the easiest assembly for a TV
You can receive a digital signal on a TV in a zone of up to 30 km on a simple single or double wire ring made of copper wire, taken with a piece of electrical wiring 2.5 mm square.
I show the technology of its assembly from two rings. If you are interested in a simplified version, then do not mount the second element.
The length of the circumference of the ring must correspond to the wavelength of the TV signal of the transmitter. In my example, this is 48 cm. I bite off two pieces of wire: L1 and L2 with a centimeter margin to connect the ends.
I bend future vibrators into rings, and I clean their ends. On a short segment, I make small rings to connect the second workpiece.
I insert one vibrator into another, I crimp the rings with pliers.
I show this process on a larger scale.
I prepare the end of the coaxial cable for connection by removing the insulation.
I twist all the ends.
I solder the joints with a soldering iron.
It turned out like this simple antenna from a wire, consisting of two rings.
Orient it with the side of the long wire to the transmitter. Rings can be bent into a hexagon shape. Then they will take a more stable position.
The photo below simply shows the principle: I did not deal with giving special dimensional accuracy to a geometric figure. Do better for yourself.
The antenna is assembled from wire. We turn it on and check the quality of the received signal on the TV.
Any soft toy will help to give decorative properties to the design. This antenna should be placed near the TV or receiver. It is undesirable to exceed the length of the coaxial cable more than half a meter.
It takes less than 10 minutes to assemble such a design, it does not present any difficulties, like the previous scheme, and its work is due to the assembled loop.
Turkina Antenna: DIY Long-Range Design for DVB T2
Initially, the operation of the receiver of this electrical circuit was developed and practically tested by the radio amateur Turkin.
Its description can be found in an article in the magazine Radio No. 11 for 2000.
Then engineer Polyakov through computer program MMANA finalized it and published an article in the same Radio. See Issue #1, 2002. A diagram of the improved design is shown in the picture below.
Metal rings of vibrators are located on the dielectric rod due to strictly defined distances in the space of the digital TV signal broadcast zone. Their role:
- D1-D3 - passive elements;
- V1, V2 - active part, collected by the scheme double Swiss square;
- R is the anti-interference shield function.
All dimensions of the vibrators and the distances between them are tied to the length of the received wave. You can calculate them according to the formulas shown in the picture.
However, I propose an easier way: an online calculator for calculating the Turkin antenna. Enter your channel frequency value in it, expressed in megahertz, and immediately get all the dimensions in millimeters.
DVB-T2 channel numbers (click for reference)
| Channel | Frequency, MHz | Channel | Frequency, MHz |
| 21 | 474 | 46 | 674 |
| 22 | 482 | 47 | 682 |
| 23 | 490 | 48 | 690 |
| 24 | 498 | 49 | 698 |
| 25 | 506 | 50 | 706 |
| 26 | 514 | 51 | 714 |
| 27 | 522 | 52 | 722 |
| 28 | 530 | 53 | 730 |
| 29 | 538 | 54 | 738 |
| 30 | 546 | 55 | 746 |
| 31 | 554 | 56 | 754 |
| 32 | 562 | 57 | 762 |
| 33 | 570 | 58 | 770 |
| 34 | 578 | 59 | 778 |
| 35 | 586 | 60 | 786 |
| 36 | 594 | 61 | 794 |
| 37 | 602 | 62 | 802 |
| 38 | 610 | 63 | 810 |
| 39 | 618 | 64 | 818 |
| 40 | 626 | 65 | 826 |
| 41 | 634 | 66 | 834 |
| 42 | 642 | 67 | 842 |
| 43 | 650 | 68 | 850 |
| 44 | 658 | 69 | 858 |
| 45 | 666 |
They, when viewed from behind, immediately formed concentric circles with a clearly defined axis, which must be directed to the transmitter.
It remains for me to solder the antenna coaxial cable to the active terminals of the Swiss double square.
I pay attention to the method of mounting the feeder. Conclusions of the rings forming the Swiss double square, are connected oppositely diagonally, and not in parallel.
Look at the layout of the vibrators in the first picture, which shows the Turkin-Polyakov antenna. An air gap of a few millimeters must be created between the bare connecting wires. It will eliminate the short circuit of the potentials of the output voltage.
I put on a ferrite ring at the cable connection point to match the wave impedances of the cable and antenna.
Its magnetic permeability should be within 400-600. I didn't check mine. It just came up.
The antenna immediately started working right out of the room. True, the distance to the transmitter at the dacha is only 40 kilometers. Haven't tested further.
For horizontal polarization of the signal, the Turkin antenna is rotated from the position indicated in the photo by 90 degrees. Then her cable immediately hangs down vertically from the center of the circles, and not from the side.
Here are 4 do-it-yourself antenna schemes for digital television that you can assemble without spending too much money and time. You can see for yourself that their designs are quite simple.
All four tested circuits worked for me immediately without connecting any amplifiers.
I believe that for residents of rural areas living in the zone of reliable reception of digital signals, the Kharchenko antenna is best suited.
With dense residential buildings in the city, I recommend checking the loop antenna made of cable or wire. It fights well with the interference that the air is saturated with from household equipment.
For those who need to catch a signal weakened by a long distance, it is best to immediately assemble the Turkin-Polyakov antenna. Her specifications practically in no way inferior to either the wave channel or the log-periodic products.
As you can see, in the article I tried to do without technical terms. He did not give the gain and standing wave, radiation pattern and other characteristics. These options can be discussed in the comments section.
Have questions? Ask, discuss, choose the most affordable and acceptable result for your case.
