Many of us have been using devices such as modems from mobile operators, which allow you to access the World Wide Web. But unfortunately, unlike broadband wired Internet, such devices have several significant disadvantages. The main one is the peculiarities of radio signal propagation in the surrounding space. Radio waves in the 3G, 4G and LTE bands have the unfortunate property of being reflected from obstacles, scattered and attenuated, and the speed and quality of the Internet connection deteriorates accordingly. What can be done in such a situation?

The easiest and cheapest way to boost the signal coming from the provider's base station to your modem is to use a homemade antenna made from improvised means, made with your own hands. Let's look together at the simplest and most popular options for manufacturing structures that amplify the radio signal arriving at the modem from the BS.

Wire antenna

The simplest option homemade antenna- this is the use of a piece of copper wire of a small cross-section, which needs to be wound in several turns around the top of the modem. We bend the remaining end of the wire, 20-30 centimeters long, vertically. This primitive method, under certain conditions, can significantly increase the stability of the received radio signal.

Can

Probably, in any home you can, if you wish, find an empty used tin can for soft drinks or coffee. This simple item can become the basis of another homemade antenna. We remove the lid of the container, make a hole in the side wall, insert the modem halfway into the case, and use a USB extension cable to connect to a computer or laptop. Next, it remains to find the best location of the structure in space. Amplification effect in in this case could be very good.

Colander 4G

Most people have a regular aluminum colander. And this piece of utensil can be used to create another simple antenna for a modem. You just need to fix the “whistle” in the bowl of the dish, for example, using adhesive tape. As they say, everything ingenious is simple.

Zigzag frame antenna of the famous Soviet radio amateur Kharchenko. To make such an amplifier you will need a copper wire with a cross section of 2.5 mm. We bend it in the shape of two combined squares, and place a modem connected via a USB cable to the computer at the connection point. We attach a thin sheet of metal to the back of the antenna as a reflector. You can make such a device quite quickly, and the gain under certain conditions can be very pleasing.

Converted satellite dish

Many of us use the services satellite television. And if you have an old satellite dish at your disposal, then it can be converted into an antenna for a 4G modem. It's very easy to do. We remove the converter from the rod and attach the modem in its place. We direct the structure towards the provider’s base station and slowly rotate it until the best result is achieved.

So, we looked at several options for making an antenna for a 4G modem with your own hands from available materials. You can try to make any of the proposed models yourself and noticeably strengthen the signal received from the provider’s base station. Good luck!

Introduction and theory under the cut. Please read carefully before asking questions and/or accusing me of incompetence.
There was a lot of information on the Internet about homemade external antennas for 3g modems, but I didn’t find anything helpful, that’s why I’m writing these lines. I am very touched by people who believe that 3g is a communication standard like GSM, but in fact it is just a generation. These same people are looking for drawings of antennas for a 3g modem... So these drawings are not there, or rather they are, but this is the same as coming to the car market and persistently demanding a carburetor for a passenger car without even specifying its model. So we will design the antenna for the CDMA2000 standard, whose operating frequencies lie in the range 821-894 MHz (and not 800 MHz as many people think). The antenna reviewed here is won't fit for operators MTS Connect, Utel (Kyivstar). Of course, I have come across proposals to catch a signal using a “nail” (aka quarter-wave vibrator), to make can antenna(the only catch is that according to calculations, you no longer need a can, but a whole bucket), the notorious Kharchenko antennas (a good option when there is still a signal, but the gain leaves much to be desired), etc.

I settled on the “Wave Channel” type antenna, also known as Uda-Yagi. The advantages are a high gain, low windage, and a highly directional bottom, but the disadvantage is extremely significant - very high manufacturing precision is required. An oversized director will become a reflector, and an active vibrator will not resonate at the frequency we need. The more accurately you do everything, the better the result will be.

The base station is located only 3 km from my house, but the windows face the other direction from the tower and the signal leaves much to be desired. At first I wanted to make an antenna with 8 directors, but it turned out that ultra-precision is needed here because going 1mm will result in attenuation instead of gain. A 3-director antenna does not require such precision manufacturing, but has insufficient gain. Therefore, I settled on a 5-director wave channel, considering it the “golden mean”. The receiving and transmitting channels are quite far apart from each other, so the antenna was designed for the middle of the receiving channel, that is, at 881 MHz. At first I wanted to design the antenna for the middle of the range as a whole (859 MHz), but since the Yagi is a narrowband antenna, we will get a gain peak in the non-operating range and less gain at operating frequencies.

The Yagi calculator program was used for design.

What do we need:
- an aluminum square profile with a cross section of 10 mm (I bought it at the epicenter), non-aluminum will do, but it is still lighter, but does not affect the characteristics of the antenna in any way;
- aluminum rod with a diameter of 5 mm and a length of 1 meter (other materials are also suitable, including copper, which is even better, but aluminum is the best price/quality ratio);
- a copper tube with a diameter of 6 mm and half a meter long (the outer diameter is indicated, the wall thickness does not matter);
- bolts with a diameter of 3 mm 7 pcs.;
- cable with wave impedance 50 Ohm;
- adapters, connectors - everything is individual for each modem, as they say, “Google to the rescue.”

Separately about the cable. To you won't fit television cable due to its resistance of 75 ohms. More precisely, it can be attached, but due to inconsistency, the losses in the cable will most likely be greater than the antenna gain. I took 10 meters of RG58 cable, it is quite cheap, but the loss is 0.6 dB per 1 meter of cable, i.e. I personally lost 6 dB, despite the fact that the difference in the signal with and without an antenna is 20 dB. Therefore, it is not worth saving on cable.

From the tools:
- saw for metal;
- drill;
- three-point tap;
- drill 2.5; 5; 6;
- flat file;
- calipers (in extreme cases, a ruler will do);
- hands.

First the drawings:

Red indicates the reflector, blue indicates the active vibrator, and green indicates the directors.

Drawing of an active vibrator (dipole):

All dimensions in the drawings are indicated in millimeters. The distance between elements is indicated by centers.

Let's start manufacturing. We take an aluminum profile, retreat an arbitrary distance from its beginning (this distance is needed for fastening, I took about 10 cm) and make a through hole with a 5 mm drill. I recommend immediately making a hole with a drill of the smallest diameter possible, and then drilling it out with a 5 mm drill. This is necessary in order not to deviate from the center axis of the profile. Next, we retreat 68 mm (according to the drawing) from the center of the previously made hole and make a through hole with a 6 mm drill (this is exactly the diameter of the active antenna vibrator). Next, we make all the holes with a 5 mm drill to accommodate the directors.

We begin to manufacture the reflector and directors. Actually, all the dimensions are indicated in the drawing, I just want to give some tips on cutting. Cut the aluminum rod according to the drawing 2-3 mm longer, after which we set and fix the required length of the element on the caliper. We file the rods with a flat file to the required length, periodically checking the size with a caliper. If the element fits tightly between the jaws for internal measurements, then you can proceed to the manufacture of the next element.

The manufacture of a loop vibrator is quite complex. It is better to fill the cavity of the tube with fine dry sand to avoid tube fractures (I did without this, but it’s still better not to risk it). To make a circle, you need to find a pipe close in diameter and bend a copper tube through it. The rest is according to the drawing.

To fix elements in the profile cavity, I suggest this option. Having inserted the element into the profile cavity perpendicular to it from above the profile, we drill a hole with a 2.5 mm drill and cut the thread with an M3 tap and with a small three-point bolt we clamp the element on top (the main thing is not to overdo it because aluminum is a very soft metal). Maybe someone will come up with a simpler or more reliable option, but with my set of tools it seemed to me that this was the most successful method of fastening.

All elements must be centered and perpendicularity checked relative to the traverse (boom, as the bourgeoisie like to call it).

Let's start soldering the reduction cable and matching loop. Cut a piece of RG58 cable 132 mm long. We remove 10 mm of outer insulation from each side of the cable piece, being careful not to damage the braid. Then we expose the inner insulation and twist the foil and braid into one bundle, fold the piece into a loop, connect the braids on each side and solder well. We strip the internal insulation to 8 mm. I think the rest is clear from the picture:

We solder the central cores to the ends of the active vibrator at the point where it breaks (15 mm in the drawing).

Some clarifications. Before you change or throw out anything from the design, it’s better to ask in the comments so that later there are no reviews “but it doesn’t work for me.” I made everything very accurately according to the calculations, but still the minimum SWR turned out to be not at a frequency of 881, but 885 MHz, which was quite acceptable for such frequencies. If you make it inaccurately, the effect will still be there, but not the maximum. At the transmission frequency (average frequency 824 MHz), the antenna performed very poorly, so I recommend that you still place the modem in the area of ​​best reception, because it feels like an internal rather than an external antenna is used for transmission.

I almost forgot about the tests. AxesstelPst EvDO BSNL program was used to evaluate the result.
The modem is simply plugged into the USB port:

Connecting the antenna:

What do we have? The signal is -62 dB, for comparison, if you are standing 20 meters from the BS, the signal will be about -40 dB, -105 dB is almost a complete absence of signal. The DRC Requested parameter is also interesting. 3.072 Mbps means that the modem is requesting the maximum possible speed and the BS station will give us the speed depending on the network load. The specific speed depends on the database load, i.e. further increasing the signal level will not improve the speed. The speed in the morning and in the evening will naturally be worse:

Good luck making it. I'm waiting for questions in the comments.

The biquad antenna was proposed by K.P. Kharchenko (1961) catch meter television channels. Of course, it was large in size: the wavelength was not small. When you need an antenna for a modem, assembled with your own hands from improvised means, you can often fit the structure in a round laser disc box; in this case, the reflector is easy to install. One blank is enough, the main thing is to look at the light so that it is not transparent (a layer of metal is required to construct the reflector). This means: the coating is suitable and perfectly reflects the waves of digital communication. We are talking about antennas for the modem - we mean two standards WiFi, 3G. The first has mastered the frequencies of household appliances and interferes with microwaves, the second is the brainchild of cellular communications. The wavelengths are, of course, similar.

Digital modems

The word modem is a derivative of two others:

1. Modulator.
2. Demodulator.

When transmitting information packets, you have to encode. Practitioners quickly discovered: if a person’s speech is broadcast into the air, the broadcast will fade out at a distance of 25 meters. Low frequency radio waves are not viable. Things are better with the wires. It is well known: analogue telephony was able to transmit speech over kilometers, using amplifiers, the limits can be expanded. However, in this case the conditions are alien to the ideal. Why is the nonsense happening? Each medium (air, iron, water) is endowed with a characteristic bandwidth, and the amount of losses depends on the frequency. Communication windows (transmitting electromagnetic radiation) used by satellite broadcasting have been identified in the atmosphere. The WiFi range (2.4 GHz) does not apply; on the contrary, the radiation is absorbed by water vapor.

Thinking in this way, engineers gave birth to an idea: information can be transmitted by encoding the parameter of the carrier wave entering the transparency window with a useful signal. On the receiving side, the information needs to be decoded. This is what modems do. Light and electromagnetic waves are transmitted through the lines and encoded with useful information. Antennas are busy converting electrical vibrations into an ethereal wave that propagates in space. This step eliminates the need to install a communication line or wire. The ether will serve to transmit information. Convenience comes at a cost, in our case the range is severely limited, and 99% of the energy is wasted if a pair of directional antennas are not used, aimed at each other. Broadcast WiFi network, 3G inevitably leads to losses. However, convenience mobile communications pays for energy.

In what cases will an external antenna for a modem help:

1. We see the reception on the balcony, but there is silence inside the apartment. The signal is picked up on the window sill, but inside the room there is a round zero. The situation is a scourge wireless networks for one simple reason: the power of transmitters is limited by law. Electromagnetic waves are harmful to health, despite the desire of officials to profit, sometimes you have to give in to the basic demands of doctors. Not sick leave, others – developing laws regulating the use of dangerous drugs.
2. Several towers are broadcasting - residents are faced with the following situation: a modem, equipped with a smart driver, stubbornly imposes communication on the point that transmits worse. At best, you can transfer it manually, even this gets boring at times. A directional antenna will help out, which we aim in the desired direction.
3. In the penumbra zone, reception of WiFi and 3G signals is uncertain and is determined by the vagaries of the weather. A directional antenna aimed towards the broadcast helps.

There are other cases. Wherever you need to improve the quality of reception, you need a homemade antenna for the modem. True, one device has been invented that allows you to increase the signal level. We mean a reflector. Customers saw a 3G amplifier in the store, representing a cylindrical surface: a flash modem was installed along the axis. The beams were concentrated in the center, improving reception. The device is passive, the price is higher than a modem with a package for six months of Internet. It is not surprising that ordinary people the size of a mountain ask how they can make an antenna for a modem with their own hands.

Modem antenna designs

Let's start with the Kharchenko biquad antenna, suitable for all digital communication bands. A copy that catches WiFi fits in a box of laser discs, which is convenient from the point of view of protection from bad weather. We would recommend using online calculators when making calculations. Since it is quite difficult to find, we took the trouble to calculate the parameters for some cases; then readers will generalize to any frequency, because the relationships will become obvious. WiFi frequencies:

• Frequency 2.6 GHz, wavelength 115.3 mm. The side of the square will be a quarter of the wavelength: 28.82. To get the total length of the figure eight, we multiply one side by 8, we get 230.6 mm. We take the reserve, it turns out to be 235 mm. The distance to the reflector will be 0.15 - 0.2 wavelengths. Let’s take something in between – 0.175. It turns out 20.2 mm.

In fact, the 2.45 GHz wave is often used. Let's do the calculation.

• The frequency is 2.45 GHz, the wavelength is calculated by dividing the speed of light by a number. Approximately the speed of light in a vacuum is 3 x 10 8 m/s, the exact value is 299792458. We calculate the wavelength... it turns out 122.36 mm. Next, we carry out the calculation along the beaten path. We get the side of the square by dividing the wavelength by 4 - 30.6 mm. The length of the wire is calculated by multiplying by 8, it turns out to be 245 mm, we take a reserve of 250. The distance to the reflector will be 112.36 x 0.175 = 21.413 mm.

It is difficult to bend the wire at a right angle. We recommend using a vice, pliers, and a hammer when making the antenna for the modem. Along with a ruler and a corner, of course. Many people have a question about how thick the wire itself should be. Let's try to answer! Reducing the frequency, the diameter increases; at 2600 MHz the parameter is 2.75 mm; those mastering 1300, therefore, should take 5.5 mm. Here are a few values:

1. 900 MHz – 8 mm;
2. 800 MHz – 9 mm;
3. 1800 MHz – 4 mm;
4. 1900 MHz – 3.8 mm.

Similarly, we obtain the result for any frequency. It is clear that violating the thickness or moving away from the calculated values ​​will not lead to fatal consequences, however, you should not get too carried away. So as not to say later that the wrong values ​​are given on the VashTekhnik website... According to our information, the GSM 1800 standard is often used in the Russian Federation, let's see which Kharchenko biquad antenna should be at the operating frequency (3G modem).

The frequency is 1800 MHz, we find the wavelength: 299792458/1800000000 = 166.6 mm. We find the side of the square by dividing by 4, it turns out 41.6 mm. The total length of the wire will be 333.1 mm. With a margin it will be 335 mm. The distance to the reflector is 166.6 x 0.175 = 29.15 mm. The wire thickness is indicated above. Design for health.

Let’s take a moment to consider other wavelengths; the calculation procedure is obvious. Here are a couple of notes on the design of a homemade antenna for a modem. If there is only one biquadrate (and we will meet more), it resembles an eight - no more. There is no intersection at the central point. The wire simply comes closer together without touching, then scatters again to the sides. It really does resemble a figure eight placed on its side (WiFi polarization is vertical). For another polarization - horizontal - we place the figure eight vertically.

It is better to take an insulated wire for the antenna. A cable core of the required thickness will do. The material does not necessarily have to be copper, it’s just that Olympic metal is not subject to electrochemical corrosion (it is always an acceptor). The structure must be protected in any case. As mentioned above, WiFi models are placed in a laser disc box, which we seal to be sure.

The figure eight stands on isolated stands that can be placed anywhere, but it is easier to use two supports in the approach area (in the middle). One edge is connected to the cable and antenna screens, the second is used to pick up the signal. Both terminals are close to each other, almost touching, there is no electrical contact at the intersection.

The signal gain will increase if you use two biquads. The central part is performed in the indicated manner, then the figure eights intersect (!) crosswise, but at the point of contact the two wires are reliably insulated from each other. The radiation pattern narrows, increasing the gain. Good techniques for catching a tower that can be seen on the horizon. If you can point the modem antenna precisely, reception will certainly improve.

The device is connected using a standard 50-ohm cable. Ideally, it’s a good idea to measure the SWR, then bring it to a value less than 2. The antenna design for the modem may be different; in a recent review, they cited designs reminiscent of those used by cell phones. Radiating sites united by matching lines.

Concluding the review, we emphasize: cellular communication standards and WiFi resemble each other. In both cases the polarization is vertical. Made for confident reception anywhere. As the wave propagates around the planet, the configuration is maintained. Vertical polarization is perpendicular to the ground. When talking on the walkie-talkie, try to hold the antenna this way.

Practice! It is known for certain that dull individuals tend to perform the simplest procedures incorrectly. Acting for show, they hold the radios horizontally, twisting them in an unimaginable way. Stick to proven solutions. Sometimes it's easier to take a couple of steps. The beam rarely changes polarization, otherwise the radio broadcasting industry would have long ago taken this nuance into account (car radios, for example).

In the modern world, a person cannot imagine life without the Internet, with the help of which you can not only always stay in touch, but also work without leaving home. Due to imperfect technology mobile transmission data in the system may experience frequent failures, so the most convenient way to access the World Wide Web at any time is to use a 3G modem.

Using this device, you can catch Internet signals transmitted over mobile networks while being in any place: in a park, in a country house or outside the city. The quality of transmission will depend on the signal strength, so the question of enhancing reception mobile network using a homemade antenna for the Internet remains relevant.

With appropriate settings, a homemade 3G antenna or together with a biquad antenna can simultaneously act as a receiver and amplifier. Biquadrat is a type of loop antenna that is part of the zigzag group. It was invented by Russian scientist Vladimir Kharchenko. It was first used in the second half of the 20th century to “catch” signals from television broadcasts. Scientists tuned this device to a frequency of 14 MHz, gave it the required position and began to receive signals from the United States of America.

Pay attention! Today, a biquad panel antenna for 3G can be bought in a specialized store, or you can make such a simple device yourself.

According to numerous calculations and experiments by V. Kharchenko, according to the output data, even the work done digital devices, which operate on mobile platforms. Without a reflector, signal reception increases to 4-5 dB, and with its implementation the indicator increases to 7-10 dB.

Directional devices

When there is a signal on the modem, but it is not strong enough, it is recommended to use simple devices to increase the power of mobile Internet reception. This method consists of better positioning the 3G modem and pointing its antenna towards the tower. The following materials can be used for these purposes:

• tin can;
• an old saucepan;
• dishes or a simple DVD.

For example, if we consider a can antenna, then you only need to punch a hole at the base of the can or in its bottom. This is necessary to secure the modem, the correct direction of which will strengthen the signal.

External antenna

Interesting! The main idea of ​​this method is to create high-quality insulation for uninterrupted operation of the device in any weather.

You also need to select the optimal signal direction point. Insulating tape should be used as insulation, which will prevent moisture from entering the microcircuits and wire connections.

A sheet of metal can act as a reflector, which should preferably be slightly rounded to concentrate the signal at one point. In the absence of a metal sheet, you can take ordinary cardboard, the base of which should be covered with foil to reflect signals.

Kharchenko antenna for 3G

Despite the fact that the device was invented in the mid-20th century, its design has not changed at all, nor has its popularity. The principle of operation is to capture electromagnetic waves through which mobile Internet transmission is carried out.

The advantage of this design is the operating range, since the signal is repeatedly reflected in the atmosphere. Waves bend around obstacles, resulting in

Interesting! The Internet can be reached even at a considerable distance.

DIY antenna for 3G modem

You can make it yourself using a basic set of tools. For this you will need:

• copper TV cable at least 35 cm long;
• coaxial cable (2-3 m);
• bottle cap, tin can or foil;
• scissors to cut the cable;
• any glue.

You also need to prepare a ruler and marker for marking, pliers and a soldering iron to attach cables to the contacts. If you don’t have glue on hand, you can make it yourself from polystyrene foam and gasoline (or acetone) by connecting the components at the bottom of a glass container.

To do this, you should take into account some subtleties.

Device and optimal dimensions

Interesting! Optimal performance A 3G modem is possible at a frequency of 2200 MHz, which is equal to a wavelength of 145 mm.

Today in stores you can still see models operating at 900 MHz, but they are no longer so relevant. The key components of the amplifier are represented by a vibrator, an antenna wire, a signal transmission unit and a reflector that eliminates interruptions and extraneous noise.

Basic requirements for a vibrator

The vibrator must be made of aluminum or copper. During the manufacturing process, you need to take into account the fact that the vibrator is small in size, so the cable should be connected by soldering. As for the cross section, it should be 5-7 mm, and the diameter should be at least 2.5-3 mm.

Important! To receive a signal regularly, the squares of the vibrator must be symmetrical, and its side surfaces must be the same size.

Cable selection

The main difference between a 3G antenna and a regular one is the size of the wave resistance, which averages 80 or 55 Ohms. To reduce possible power loss, it is recommended to use a wire that has lower resistance. The advantages of such cables include better electronic performance, a guarantee of minimal signal loss and compatibility with the mechanical dimensions of the vibrator.

Specifics of the reflector design

You can use any steel plate as a screen, or cut a tin base from the bottom of an unusable aluminum pan. If you don’t have anything metal at hand, you need to take a sheet of cardboard or plywood, after wrapping it in foil. A DVD disc with one side covered with aluminum foil has excellent conductivity. This device perfectly reflects waves, making work much easier and also having an aesthetic appearance.

Interesting! To make a homemade antenna for the Internet from a disk, you just need to coat it with glue, and then securely glue it to a bottle cap. At the next stage, the distance of the vibrator from the reflector is adjusted, and this is done with additional washers from the screws.

Device creation process

When creating a vibrator, not only size is important, but also symmetry. To give the installation the most accurate symmetry, all faces of the squares must be identical, and this result can be achieved using one of two methods:

• pre-mark the wire using a black marker;
• use a diagram or control template that has a certain length.

The pliers must be installed on the cable markings, and then bend the wire exactly 90° to adhere to the bend along the square. Next, the vibrator must be bent using the reference drawing for each face of the square and the remaining part of the bent wire must be cut using side cutters.

Connection and signal transmission options

In the center of the lid plastic bottle You need to drill a hole using a drill, the size of which should be slightly larger than the diameter of the cable. Next, one end should be inserted into the hole and disassembled in such a way that the central core with the soldering area is exposed. You can connect the cables using a homemade soldering iron, and then pull the cover onto the vibrator, gradually moving along the wire.

Important! In order to increase reliability in the plastic plug, you can use glue and wiring from small cuts.

You need to insert a wire through the central hole of the disk, and then glue it to the end of the plug. Such effective method installation does not imply that electrical contact will occur between the vibrator and the reflector.

Send data wirelessly

To starting points coaxial cable you need to connect electrodes that will play the role of a generator unit emitting a powerful electric wave. Using a thread, you need to make two turns around the modem body (along its outer contour), add 7 mm and cut three strips from metal or foil, the length of which should be 80 mm and the width 45 mm.

The electrodes soldered to the Kharchenko antenna are separated to a certain distance and directed so that the received signal is sent to the 3G modem antenna.

Interesting! To check the operation of the finished device, you should insert it into the computer connector and evaluate the quality of the supplied network.

Is it possible to remake a TV antenna for a 3G modem?

Many users today are wondering whether it is possible to make a Kharchenko antenna for a 3G modem with your own hands or use a regular one TV antenna for supplying Internet signals. Even though these two devices contain aluminum, using or modifying a TV antenna for a 3G modem or cell phone It is highly not recommended because they have different frequency ranges. As a result, the quality of communication will be much worse and lower.

Thus, the process of making an antenna for the mobile Internet with your own hands is quite feasible. To do this, you just need to study the sequence of actions described above and prepare the necessary materials.

Many people in the modern world use mobile internet- with the help of it a person can communicate remotely, receive information and even work. But the provider does not always provide users with a stable connection speed due to the characteristics of communication reception, which may be limited by terrain features, a large distance to the transmitter, and other factors.

A homemade antenna for a 3g modem will help you improve the speed and range of signal reception. We offer you several instructions on how to make an antenna for a 3G modem with your own hands.

Kharchenko's method

We recently wrote how to make an antenna for television reception with your own hands. But did you know that you can make a homemade antenna for a 3G modem in a similar way?

We will need:

• Copper wire or wire, you will need a section of about 30 centimeters;
• Coaxial cable with a resistance of 50 or 75 Ohms;
• A piece of foil or DVD as a reflector;
• Tools: knife, soldering iron, pliers, glue, ruler and pencil;
• Plastic bottle cap to separate the antenna from the reflector.

Production of biquadrat Kharchenko

In photographs of homemade antennas for 3G modems you can see its approximate appearance. First, you need to make markings on the copper wire with a pencil: the length of the outer side of each square should be approximately 35-36 mm.

Carefully bend the wire along the markings, helping yourself with pliers. You should get a symmetrical design of two squares touching at the corners. Remove the remaining pieces of wire.

Make a hole in the cover and insert the end of the cable into it. Separate the cable, exposing the inner conductor and shield for soldering.

Next, you should solder the antenna to the cable and connect it to the modem. Soldering proceeds as follows: solder the central core to the middle of the antenna on one side, and the screen on the other. Then move the cover to the antenna, you can further strengthen and insulate the structure with glue or sealant.

Insert the reflector disk into the wire through the hole, move it towards the antenna and glue it to the cover. Solder the connector to the cable on the other side for connecting to the modem. Connect the antenna to the modem. Enjoy the results of your work!

Double ring antenna

The next method of creating a homemade antenna is more difficult to implement, but gives a greater effect. To complete it you will need:

• Copper wire or wire;
• Reflector - a flat long tin can, a piece of foil, etc.;
• Coaxial cable with a resistance of 75 Ohms;
• A short metal tube into which a cable can be threaded;
• Connector for connecting the antenna to the modem;
• Tools: soldering iron, knife, ruler and pencil.

Detailed manufacturing instructions:

• Look on the Internet for a Bi-Loop antenna diagram for a 3g modem - on it you will see a design similar to the Kharchenko antenna, but in the form of two rings;
• Make markings on the wire with a pencil: for waves with a length of 2050 MHz, the length of each ring should be approximately 146 mm;
• Carefully bend the wire into a double ring. You can also make two rings with gaps approximately 3mm long and solder them end to end, leaving the gaps open;
• Make a reflector. Minimum dimensions: height - 120 mm, width - 170 mm. Any metal panel will do; if you have available materials, you can use foil or tin from a tin can;
• Make a hole in the middle of the reflector through which to insert a metal tube - from the side connecting to the antenna, the length of the tube should be approximately 18 mm! Solder the tube to the reflector on the other side;
• Separate the cable with a knife: the screen should be soldered and the conductor should be slightly exposed;
• Pass the cable into the tube and solder the antenna to it: the upper part should be soldered to the conductor, and the lower part to the copper tube;
• Solder the tube and cable braid;
• Additionally, to strengthen the signal, you can use a satellite dish by installing a ready-made antenna on the bracket;
• The other end of the cable should be connected to the modem connector using a soldering iron;
• Connect the antenna to the modem. Ready!

Now you know several ways to make an antenna for a 3G modem with your own hands. The above methods should help you solve problems with low Internet connection speed.

Photo of antennas for 3g modem