Basic antenna made from a bicycle wheel. Homemade antennas: outdoor, home. A simple Wi-Fi antenna made from a metal can

On this page I posted detailed photo instructions for making a whip antenna for VHF transmitters, without delving into the very essence of transmitting radio signals through the air. However, the article provides a calculation of the length of a quarter-wave whip antenna.

A quarter-wave VHF whip antenna (in the world of security alarms, just a “pin”) costs 200-300 rubles at retail. Branded antennas from the C.NORD company are called CN AGV and are sold in various sizes (the length of the pin is adjusted to the frequency of the radio transmitter). Since such antennas are designed for radio transmitters of a fairly wide frequency range (146-174 MHz), then you must initially select an antenna of the required size or adjust it (bite off the excess, but do not increase it, in which case change it to another antenna). Sometimes you have to “bite off” excess from a whip antenna when switching an object from one private security system to another, because the frequency of the transmitter changes and signals from a pin of the wrong length do not go well.

Now we will essentially make a copy of the CN AGV antenna, but we will make it for a specific frequency.

It all starts with preparing the necessary material, tools and with calculating the length of the pin at a frequency of 163,325 kHz (I chose the frequency as an example, I don’t know which private security system works on it).

For a homemade whip antenna, we will need the following tools: soldering iron, hair dryer (you can use a gas lighter, wire cutters, sandpaper; material: galvanized wire 2-4 mm in diameter, solder, soldering acid, pl-259 connector, heat-shrinkable tube.

Let's get back to the calculations. On a notepad I described in detail how the length of a quarter-wave whip antenna is calculated. You should also know that the length of the whip antenna is measured from the end of the washer of the pl-259 connector.

As a result, after all the calculations, we understand that the length of the pin, taking into account the soldering of the pl-259 connector, should be 49.9 cm. For the pin, I use ordinary galvanized wire with a thickness of 2-4 mm. It is rigid enough to serve as a whip antenna.

We bend a piece of wire so that it becomes even. The quality of the antenna depends on this, so it will be even better if you can find a stiffer metal pin/wire/spoke of a suitable thickness.

Let's try on how our wire will fit into the connector. If it doesn’t fit, as in our case, then we grind/sharpen the end of the wire using sandpaper, but only as far as the end should fit into the connector.

Let's try how the pin will fit into the plug

A screwdriver caught my eye, so I was able to quickly sharpen the end of the wire:

After the end of the wire begins to fit freely into the pl-259 connector, we stop sharpening. It will be even better if it fits tightly inside the central hole of the connector.

The part of the wire that goes into the central plug of the connector must be treated with soldering acid and soldered with tin.

Place the VHF plug on the soldered end of the wire and mark for yourself the part of the wire that will touch the connector washer. Isolate this part from the washer as best as possible using heat shrink as shown in the figure and photo.

Also insulate the entire pin with another heat-shrinkable tube, because the antenna essentially must be insulated.

Isolation of "dangerous" areas. In these places, the central core may short-circuit with the common wire

Now the plug can be soldered. After soldering, be sure to check with a multimeter to see if there is a short circuit between the central core and the nut of the pl-259 plug.

Now the antenna is ready, you can insert it into the radio transmitter. Be sure that the signals from such an antenna will “reach” the repeater / base receiver.

Buy good antenna going to the dacha is not always advisable. Especially if she is visited from time to time. The point is not so much the cost, but the fact that after a while it may not be there. Therefore, many people prefer to make an antenna for their dacha themselves. Costs are minimal, quality is good. And the most important point- A TV antenna can be made with your own hands in half an hour or an hour and then, if necessary, can be easily repeated...

Digital television in the DVB-T2 format is transmitted in the UHF range, and there is either a digital signal or it is not. If the signal is received, then the picture appears good quality. Due to this. for reception digital television Any decimeter antenna is suitable. Many radio amateurs are familiar with the TV antenna, which is called “zigzag” or “figure eight”. This DIY TV antenna can be assembled literally in a matter of minutes.

To reduce the amount of interference, a reflector is placed behind the antenna. The distance between the antenna and the reflector is selected experimentally - according to the “purity” of the picture
You can attach foil to the glass and get a good signal...
Copper tube or wire is the best option; it bends well and is easy to bend.

It is very simple to make; the material is any conductive metal: tube, rod, wire, strip, corner. Despite its simplicity, she accepts it well. It looks like two squares (rhombuses) connected to each other. In the original, there is a reflector behind the square for more reliable signal reception. But it is more needed for analog signals. To receive digital television, you can do without it or install it later if the reception is too weak.

Materials

Copper or aluminum wire with a diameter of 2-5 mm is optimal for this homemade TV antenna. In this case, everything can be done in literally an hour. You can also use a tube, corner, strip of copper or aluminum, but you will need some kind of device to bend the frames to the desired shape. The wire can be bent with a hammer, securing it in a vice.

You will also need a coaxial antenna cable of the required length, a plug suitable for the connector on your TV, and some kind of mount for the antenna itself. The cable can be taken with a resistance of 75 Ohms and 50 Ohms (the second option is worse). If you are making a TV antenna with your own hands for installation outdoors, pay attention to the quality of the insulation.

The mounting depends on where you are going to hang your homemade antenna for digital television. On the upper floors, you can try to use it as a home decoration and hang it on curtains. Then you need large pins. At the dacha or if you take a homemade TV antenna to the roof, you will need to attach it to a pole. For this case, look for suitable fasteners. To work, you will also need a soldering iron, sandpaper and/or file, and a needle file.

Do you need a calculation?

To receive a digital signal, there is no need to count the wavelength. It is simply advisable to make the antenna more broadband in order to receive as many signals as possible. To do this, some changes were made to the original design (pictured above) (further in the text).

If you wish, you can make a calculation. To do this, you need to find out what wavelength the signal is broadcast on, divide by 4 and get the required side of the square. To obtain the required distance between the two parts of the antenna, make the outer sides of the diamonds slightly longer and the inner ones shorter.

Drawing of a figure-of-eight antenna for receiving digital TV

• The length of the “inner” side of the rectangle (B2) is 13 cm,
• “external” (B1) - 14 cm.

Due to the difference in lengths, a distance is formed between the squares (they should not be connected). The two extreme sections are made 1 cm longer so that you can fold the loop to which the coaxial antenna cable is soldered.

Making a frame

If you count all the lengths, you get 112 cm. Cut off the wire or whatever material you have, take pliers and a ruler, and start bending. The angles should be 90° or so. You can make a little mistake with the lengths of the sides - this is not fatal. It turns out like this:

• The first section is 13 cm + 1 cm per loop. The loop can be bent immediately.
• Two sections of 14 cm each.
• Two 13 cm each, but with a turn in the opposite direction - this is the point of inflection onto the second square.
• Again two 14 cm each.
• The last one is 13 cm + 1 cm per loop.

The antenna frame itself is ready. If everything was done correctly, there will be a distance of 1.5-2 cm between the two halves in the middle. There may be small discrepancies. Next, we clean the loops and the bend point to bare metal (treat it with fine-grain sandpaper), and tin it. Connect the two loops and crimp them with pliers to hold them tightly.

Cable preparation

We take the antenna cable and carefully clean it. How to do this is shown in step by step photo. You need to strip the cable on both sides. One edge will be attached to the antenna. Here we strip it so that the wire sticks out 2 cm. If it turns out more, the excess (later) can be cut off. Twist the screen (foil) and braid into a bundle. It turned out to be two conductors. One is the central monocore of the cable, the second is twisted from many braided wires. Both are needed and need to be tinned.

We solder the plug to the second edge. A length of 1 cm or so is sufficient here. Also form two conductors and tin them.

Wipe the plug in the places where we will solder with alcohol or solvent, and clean it with emery (you can use a needle file). Place the plastic part of the plug on the cable, now you can start soldering. We solder a monocore to the central output of the plug, and a multicore twist to the side output. The last thing is to crimp the grip around the insulation.

Then you can simply screw on the plastic tip and fill it with glue or non-conductive sealant (this is important). While the glue/sealant has not hardened, quickly assemble the plug (screw on the plastic part) and remove the excess compound. So the plug will be almost eternal.

DIY DVB-T2 TV antenna: assembly

Now all that remains is to connect the cable and the frame. Since we were not tied to a specific channel, we will solder the cable to the middle point. This will increase the broadband of the antenna - more channels will be received. Therefore, we solder the second cut end of the cable to the two sides in the middle (those that were stripped and tinned). Another difference from the “original version” is that the cable does not need to be routed around the frame and soldered at the bottom. This will also expand the reception range.

The assembled antenna can be checked. If the reception is normal, you can finish the assembly - fill the solder joints with sealant. If the reception is poor, try first to find a place where the fishing is better. If there are no positive changes, you can try replacing the cable. To simplify the experiment, you can use regular telephone noodles. It costs a penny. Solder the plug and frame to it. Try it with her. If it catches better, it’s a bad cable. In principle, you can work on “noodles”, but not for long - they will quickly become unusable. It is better, of course, to install a normal antenna cable.

To protect the junction of the cable and the antenna frame from atmospheric influences, the soldering points can be wrapped with regular electrical tape. But this method is unreliable. If you remember, you can put on several heat-shrinkable tubes before soldering to insulate them. But the most reliable way is to fill everything with glue or sealant (they should not conduct current). As a “case” you can use lids for 5-6 liter water cylinders, ordinary plastic lids for jars, etc. We make indentations in the right places - so that the frame “sits” in them, do not forget about the cable outlet. Fill it with a sealing compound and wait until it sets. That's it, your DIY TV antenna for receiving digital television is ready.

Homemade double and triple square antenna

This is a narrowband antenna that is used if you need to receive weak signal. It can even help if a weaker signal is “clogged” by a stronger one. The only drawback is that you need precise orientation to the source. The same design can be made to receive digital television.

You can also make five frames - for a more confident reception
It is not advisable to paint or varnish - reception deteriorates. This is only possible in close proximity to the transmitter

The advantages of this design are that reception will be reliable even at a considerable distance from the repeater. You just need to specifically find out the broadcast frequency, maintain the dimensions of the frames and the matching device.

Construction and materials

It is made from tubes or wire:

• 1-5 TV channel MV range - tubes (copper, brass, aluminum) with a diameter of 10-20 mm;
• 6-12 TV channel MV range - tubes (copper, brass, aluminum) 8-15 mm;
• UHF range - copper or brass wire with a diameter of 3-6 mm.

The double square antenna consists of two frames connected by two arrows - upper and lower. The smaller frame is a vibrator, the larger one is a reflector. An antenna consisting of three frames gives a higher gain. The third, smallest square is called the director.

The upper boom connects the middle of the frames and can be made of metal. The lower one is made of insulating material (textolite, gettinax, wooden plank). The frames must be installed so that their centers (the points of intersection of the diagonals) are on the same straight line. And this straight line should be directed towards the transmitter.

The active frame - the vibrator - has an open circuit. Its ends are screwed to a textolite plate measuring 30*60 mm. If the frames are made from a tube, the edges are flattened, holes are made in them and the lower arrow is attached through them.

The mast for this antenna must be wooden. At least the upper part of it. Moreover, the wooden part should start at a distance of at least 1.5 meters from the level of the antenna frames.

Dimensions

All dimensions for making this TV antenna with your own hands are given in the tables. The first table is for meter range, the second - for decimeter.

In three-frame antennas, the distance between the ends of the vibrator (middle) frame is larger - 50 mm. Other sizes are given in the tables.

Connecting an active frame (vibrator) via a short-circuited cable

Since the frame is a symmetrical device, and it must be connected to an asymmetrical coaxial antenna cable, a matching device is required. In this case, a balancing short-circuited loop is usually used. It is made from pieces antenna cable. The right segment is called the “loop”, the left one is called the “feeder”. A cable is attached to the junction of the feeder and the cable, which goes to the TV. The length of the segments is selected based on the wavelength of the received signal (see table).

A short piece of wire (loop) is cut at one end by removing the aluminum screen and twisting the braid into a tight bundle. Its central conductor can be cut down to insulation, since it does not matter. The feeder is also cut. Here, too, the aluminum screen is removed and the braid is twisted into a bundle, but the central conductor remains.

Further assembly proceeds like this:

• The braid of the cable and the central conductor of the feeder are soldered to the left end of the active frame (vibrator).
• The feeder braid is soldered to the right end of the vibrator.
• The lower end of the cable (braid) is connected to the feeder braid using a rigid metal jumper (you can use wire, just make sure there is good contact with the braid). In addition to the electrical connection, it also sets the distance between sections of the matching device. Instead of a metal jumper, you can twist the braid of the lower part of the cable into a bundle (remove the insulation in this area, remove the screen, roll it into a bundle). To ensure good contact, solder the bundles together with low-melting solder.
• The cable pieces must be parallel. The distance between them is about 50 mm (some deviations are possible). To fix the distance, clamps made of dielectric material are used. You can also attach a matching device to a textolite plate, for example.
• The cable going to the TV is soldered to the bottom of the feeder. Braid is connected to braid, center conductor to center conductor. To reduce the number of connections, the feeder and cable to the TV can be made single. Only in the place where the feeder should end must the insulation be removed so that the jumper can be installed.

This matching device allows you to get rid of interference, a blurred circuit, a second blurry image. It will be especially useful for long distance from the transmitter when the signal becomes clogged with interference.

Another variation of the triple square

In order not to connect a short-circuited loop, the triple square antenna vibrator is made elongated. In this case, you can connect the cable directly to the frame as shown in the figure. Only the height at which the antenna wire is soldered is determined in each case individually. After the antenna is assembled, “testing” is carried out. The cable is connected to the TV, the central conductor and braid are moved up/down, achieving a better image. In the position where the picture will be clearest, the antenna cable branches are soldered, and the soldering points are insulated. The position can be any - from the bottom jumper to the transition point to the frame.

Sometimes one antenna does not give the desired effect. The signal turns out to be a weak image - black and white. In this case standard solution— install a television signal amplifier.

The simplest antenna for a summer residence is made from metal cans

To make this television antenna, in addition to the cable, you will only need two aluminum or tin cans and a piece of wooden plank or plastic pipe. Cans must be metal. You can take aluminum beer beers, or you can take tin ones. The main condition is that the walls are smooth (not ribbed).

The jars are washed and dried. The end of the coaxial wire is cut - by twisting the braided strands and clearing the central core of insulation, two conductors are obtained. They are attached to banks. If you know how, you can solder it. No - take two small self-tapping screws with flat heads (you can use “fleas” for drywall), twist a loop at the ends of the conductors, thread a self-tapping screw with a washer installed on it through it, and screw it to the can. Just before this you need to clean the metal of the can by removing the deposits using fine-grain sandpaper.

The cans are secured to the bar. The distance between them is selected individually - according to the best picture. You shouldn’t hope for a miracle - there will be one or two channels in normal quality, or maybe not... It depends on the position of the repeater, the “cleanliness” of the corridor, how correctly the antenna is oriented... But as a way out in an emergency, this is an excellent option.

A simple Wi-Fi antenna made from a metal can

An antenna for receiving a Wi-Fi signal can also be made from improvised means - from a tin can. This DIY TV antenna can be assembled in half an hour. This is if you do everything slowly. The jar should be made of metal, with smooth walls. Tall and narrow canning jars work great. If you will be installing a homemade antenna on the street, find a jar with a plastic lid (as in the photo). The cable is an antenna, coaxial, with a resistance of 75 Ohms.

In addition to the can and cable, you will also need:

• RF-N connector;
• a piece of copper or brass wire with a diameter of 2 mm and a length of 40 mm;
• cable with a socket suitable for Wi-Fi map or adapter.

Wi-Fi transmitters operate at a frequency of 2.4 GHz with a wavelength of 124 mm. So, it is advisable to choose a jar such that its height is at least 3/4 of the wavelength. For this case, it is better that it be more than 93 mm. The diameter of the can should be as close as possible to half the wavelength - 62 mm for a given channel. There may be some deviations, but the closer to the ideal, the better.

Dimensions and assembly

When assembling, a hole is made in the jar. It must be placed strictly at the desired point. Then the signal will be amplified several times. It depends on the diameter of the selected jar. All parameters are shown in the table. You measure the exact diameter of your can, find the right stitch, and have all the right dimensions.

D - diameter	Lower limit of attenuation	Upper limit of attenuation	Lg	1/4 Lg	3/4 Lg
73 mm	2407.236	3144.522	752.281	188.070	564.211
74 mm	2374.706	3102.028	534.688	133.672	401.016
75 mm	2343.043	3060.668	440.231	110.057	330.173
76 mm	2312.214	3020.396	384.708	96.177	288.531
77 mm	2282.185	2981.170	347.276	86.819	260.457
78 mm	2252.926	2942.950	319.958	79.989	239.968
79 mm	2224.408	2905.697	298.955	74.738	224.216
80 mm	2196.603	2869.376	282.204	070.551	211.653
81 mm	2169.485	2833.952	268.471	67.117	201.353
82 mm	2143.027	2799.391	256.972	64.243	192.729
83 mm	2117.208	2765.664	247.178	61.794	185.383
84 mm	2092.003	2732.739	238.719	59.679	179.039
85 mm	2067.391	2700.589	231.329	57.832	173.497
86 mm	2043.352	2669.187	224.810	56.202	168.607
87 mm	2019.865	2638.507	219.010	54.752	164.258
88 mm	1996.912	2608.524	213.813	53.453	160.360
89 mm	1974.475	2579.214	209.126	52.281	156.845
90 mm	1952.536	2550.556	204.876	51.219	153.657
91 mm	1931.080	2522.528	201.002	50.250	150.751
92 mm	1910.090	2495.110	197.456	49.364	148.092
93 mm	1889.551	2468.280	194.196	48.549	145.647
94 mm	1869.449	2442.022	191.188	47.797	143.391
95 mm	1849.771	2416.317	188.405	47.101	141.304
96 mm	1830.502	2391.147	185.821	46.455	139.365
97 mm	1811.631	2366.496	183.415	45.853	137.561
98 mm	1793.145	2342.348	181.169	45.292	135.877
99 mm	1775.033	2318.688	179.068	44.767	134.301

The procedure is as follows:

You can do without an RF connector, but with it everything is much simpler - it’s easier to position the emitter vertically upward, connect the cable going to the router or Wi-Fi card.

Convenient high-frequency (HF) connectors, splitters and “adapters” do not surprise anyone today. Moreover, it is strange that they appeared for mass use by radio amateurs relatively recently, although professional activity have been used for decades, especially in radio measurements. Similar RF accessories were previously included with radio measuring instruments as part of delivery kits and spare parts, which was caused by the “different caliber” of RF input and output connectors, the geometry of coaxial cables and, to some extent, concern for ease of use and experimentation. With their standardization, the situation has improved, but problems remain - in the West, inch dimensions of threads and diameters are used, while here we use metric ones. Therefore, until now, RF accessories do not always “mate”, causing significant inconvenience, for example, when using externally identical CP and BNC connectors. But this did not last long, because both suppliers and consumers, including radio amateurs, almost completely switched to “external” standards for HF accessories and cable products.

Something similar, but for other tasks, occurs in a wide variety of technical areas, for example, in plumbing. There are also tubular (hose) connectors for different diameters and threads, adapters from “thread A” to “thread B”, couplings, elbows, plugs, splitters, filters, fittings.

Many citizens are faced with this when installing water and gas consumption meters, modern plumbing, boiler and gas equipment, replacing outdated mixers, valves, etc.

It is unnecessary to remind you that the use of standard accessories is more convenient and much more technologically advanced than traditional soldering or metal welding, although not always cheaper - bayonet or threaded connections, welding of plastics allow you to quickly and reliably perform installation by aggregating almost any “scheme” dictated by the functional purpose.

It should be noted that plumbing accessories for metal and plastic pipelines differ in materials and principle of articulation - threading and welding of plastics, respectively. Therefore, before purchasing them, the issue should be studied more deeply in order to avoid unnecessary material costs.

The properties of reliability and manufacturability attract attention when constructing HF/VHF antennas and feeder devices, where accessories of both types can be successfully used. Wherein
needs to be kept in mind main question— conductive material of the emitter.

Suppose you need to mount a magnetic loop antenna. Radio amateurs know that the main difficulty in this case lies in the selection of a rigid antenna ring support of a relatively large diameter, for which sports hoops (duralumin, polyethylene) and even the rim of a bicycle wheel are used. However, with such solutions it is not possible to vary the diameter of the structure, since it is initially specified. This does not allow achieving the desired antenna size in most cases, because the designer is deprived of such an opportunity by “initial conditions”. Fan struts made of wood are also used, for example, like a circular zigzag antenna, but they occupy a certain area, “loading” the space, and are unstable in geometry and parameters.

It is much more convenient to use plumbing connectors and other accessories as “ antenna designer" A tubular plumbing connector (TSC) is a piece of flexible pipe, solid or corrugated, cylindrical in shape, made of metal (copper, stainless steel) or plastic. Plastic TCCs are often reinforced with an outer mesh braid of wire with an anti-corrosion coating. TCC is equipped with two tips “socket” - “pin” with internal and external threads 1/2" (about 12mm), respectively. By screwing several TCCs, we get the desired size; in this case, the design can be given the shape of a broken line, circle or polygon.

It is preferable, of course, to use TSS made of copper tubes, since the “magnetic loop” antenna has high currents. The shortened design may contain “inserts” of plastic TCCs if it is planned to use ladders, spiral or loop type extension cords, or a tuning capacitor in the body of the emitter. In such a scheme, plastic TCCs are used as frames of inductors, spirals or holders of loop modules, as well as dielectric gaps. The point of our constructions is to ensure the rigidity and manufacturability of the assembly of antenna structures in the process of experiments, research and, after achieving success, record the result.

The figure shows the antenna model ART 073 Trapped balcony antenna 10-15-20-40 m manufactured by ECO Antenne, Italy, in position.

Without going into details of its attribution to a specific type of shortened antennas (a curved dipole or 0.25L pin, a frame with ladders and a telescopic tuning section), we see that it is easily repeated from the elements of our “antenna designer” as a possible type of geometry. At the same time, the cost of the antenna is reduced by an order of magnitude and the efficiency of varying sizes within a wider range is gained.

The following figure shows the balcony vertical of the VE3IVM-L VHF antenna in the operating position, which can also be easily implemented using plumbing accessories, including inclined counterweights.

A design feature is the need for a basic dielectric splitter and external connection of the grounded parts of the antenna. No less convenient is the assembly and installation of Yagi antennas and antennas of other types. Of course, there may be cases where the necessary fragments of the selected geometry are missing from the “designer”, for example, elements of fastening, fixing, insulation, but this is a common design practice decided by a radio amateur in real conditions. These elements can be found in the range of accessories for wiring household electrical networks (polyethylene staples, grips, clamps, etc.).

It is appropriate to recall that TCC connections must be made without sealing gaskets, which should be removed from the union nuts and removed from the body of the threaded ends. Particular attention should be paid to mating the TCC with selected coaxial connectors (PL, SO, BNC). If threaded connections are carefully made using wrenches, the electrical parameters of the completed antenna structures are no different from their soldered (welded) counterparts.
Get creative, colleagues! 73!

The advent of personal computers led to the displacement of large computers such as EC. In our country, computer centers, having acquired personal computers, they immediately dismantled and simply threw the large computers into a landfill.

Our savvy people have found use for many of the parts included in discarded computers. This is how a simple antenna appeared, made on the basis of an aluminum disk of the magnetic memory of the EC “Row” computer, which was at one time widespread in our vast country.

And now, 10 years after the “glorious” perestroika in our country, the antenna can be purchased on the market at an affordable price. Due to its simplicity of design, combined with good characteristics, the antenna has become widespread and has truly become a popular design.

Antenna design

This antenna is a disk with an outer diameter of 356 mm, an inner diameter of 170 mm and a thickness of 1 mm, in which a 10 mm wide cut is made (Fig. 1.e).

A printed circuit board made of fiberglass laminate 1 mm thick is installed in place of the cut (Fig. 1.6). This board has two holes for attaching the antenna with M3 screws.

Rice. 1. The design of a television antenna made of an aluminum disk of computer magnetic memory (a) and the mounting plate attached to it (6).

TO printed circuit board, attached to the antenna, the leads of the matching transformer and the reduction cable are soldered. Analysis of the quality of work showed that its work is largely determined by the presence of matching transformer T1 (Fig. 2).

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 a thickness of 2...3 mm.

Rice. 2. Diagram of a matching transformer for a television antenna made of an aluminum disk.

The transformer windings are wound with a single-core insulated wire with a core diameter of 0.2...0.25 mm and have the same number of turns, from 2 to 3 turns. The length of the coil taps is approximately 20 mm.

With such a transformer, reception in the meter and decimeter ranges is possible at a distance of 25...30 km from the television center. At a distance of up to 50 km from the television center, the antenna with a transformer works satisfactorily only on decimeter channels.

At a distance of more than 50 km from the transmitting TV tower, the reception quality is poor. Without a matching transformer, the range of reception of television programs on the antenna is halved. In this case, double image appears and its clarity is lost. The reason lies in the inconsistency between the antenna and the reduction cable; the antenna has balanced output, and the cable is asymmetrical.

Double disc version

Practice shows that it is possible to significantly improve the quality of reception with this antenna without a matching transformer. To do this, you need to assemble an antenna from two disks and connect the reduction cable directly to the antenna terminals (Fig. 3).

Structurally, such an antenna is made of two disks with cuts 10 mm wide, which are connected by two mounting plates made of double-sided foil fiberglass laminate measuring 30x90 mm.

The connection can also be made with plates made of one-sided foil fiberglass, brass or copper with a thickness of 0.5...1 mm. To connect the disks, 8 M3 or M4 screws are used.

Rice. 3. Design of a TV antenna from two aluminum disks of computer magnetic memory without a matching transformer.

The central core of the cable is soldered to point 1, and the braid to point 2. The quality of TV signal reception on an antenna with two disks is higher than with one disk, which is noticeable especially at a great distance from the television center.

Literature: V.M. Pestrikov - Encyclopedia of amateur radio.

To make a TV antenna, you will need:
- aluminum or copper wire;
- antenna connector;
- tree;
- 2 bicycle rims;
- board;
- plastic sewer pipe;
- plastic pipes;
- carpentry or plumbing tools.

The wire must be single-core, but at the same time thick enough. Perfect option - tv cable, but it is not always at hand.

If the TV center is close

In exceptional cases, when the television center is located close to the reception point, you can simply receive the signal using a piece of wire. Take 1.5 m of thick aluminum wire, strip about 1 cm from one end, and use it to adjust the thickness to the central socket of the TV antenna connector. Plug the wire into the connector. By turning the wire vertically or horizontally, bending it at different points and empirically adjusting the length, tune the antenna to the television station. This method is suitable when the distance to the telecentre does not exceed 1 km.

Universal antenna

In other cases, you will need to make a special antenna. One of the main requirements for a TV antenna is its broadband. Do broadband antenna type “dipole” can be done using improvised means. Such an antenna will consist of two vibrators. For it to be broadband, their area must be large. Take 2 rims from bicycle wheels with spokes and fasten them to an insulating beam so that the distance between the edges of the rims is approximately 50 cm. As such a beam, you can use a piece of sewer plastic pipe (preferably made of light plastic, it has better insulating properties), wooden board (in this case, take care of insulation, since wet wood can conduct current), any other insulating material of sufficient size and strength.

Using screws or rivets, make bends from each of the rims. Connect the leads to the TV using a two-wire line. This method is suitable for TVs with a high-impedance input (200 Ohm). But most often, TVs are equipped with a 75-50 Ohm coaxial input; to connect your antenna to such a TV, you will need a matching transformer. It is made from pieces of coaxial cable. It is also connected to the TV using a coaxial cable. Not only wheels from an old bicycle are suitable as dipole vibrators. You can use, for example, aluminum sports hoops and any other objects of suitable shape and size. Such an antenna is directional, so it must be pointed at the television center.