DIY 4g lte antenna for modem

Mobile Internet is still inferior to home Internet in speed. Subscribers are not always in a stable coverage area. If the signal is weak, page loading speed will be slow. One solution is an external antenna for a USB modem. You can either buy it or make it yourself from available materials.

2 What types of 3G/4G antennas are there?
3 Making an antenna from a tin can
4 Wire antenna
5 Kharchenko Antenna (biquadrat): simple step-by-step instructions
5.1 Video: how to make a Kharchenko antenna

6 Other options for homemade antennas

7 How to test changes

Cutting files with administrator rights

To say goodbye to unnecessary information, you can also use administrator rights. For this:

First, enter cmd into the search bar of the Start button.
Secondly, right-click on the result obtained and select the line “Run as administrator”.
Thirdly, in the window that appears, enter the command oppwiz.cpl and press the “Enter” button.
After these steps, the “Uninstall or change a program” window will open, where you can find the desired program. And delete it by clicking the appropriate button.

What is needed for the Internet at the dacha

If you live far from city communications, for example, in the summer at the dacha, but also want to have mobile Internet for work, study or entertainment on a computer or laptop, then you will need:

3G modem
SIM card with Internet traffic enabled

Optional:

a cord from a USB computer to a modem (can be just a USB cable, or maybe a special adapter for a UTP cable, which is used for local networks).
Wi-Fi router

Pros of a Wifi router

If you plug the modem directly into the computer, then you can access the Internet exclusively through this very computer, which must be constantly turned on for this.

Kharchenko antenna: how to make and principle of operation

The Kharchenko antenna is one of the simplest antennas in design for 4G. It is named after the scientist-inventor.

Parts needed to create:

wire;
coaxial cable;
wooden slats;
pliers, hammer, knife.

After preparing the materials, it is necessary to calculate the antenna. To do this, there are special online calculators that make the work easier.

Assembly sequence:

Determination of wave polarization and frequency. The device must be linear.
Creation of a biquad antenna device in the form of a zigzag made of copper. All elements are located in the corners. For horizontal type polarization, the figure eight must stand upright. If you do vertical polarization, the structure lies on its side.
Calculation of the side of a square using a special formula: wavelength divided by four.
Creating an oval-shaped structure that should be pulled together in the center across the larger side. The sides do not touch, but are in close proximity to each other.
Connecting the antenna cable to the approach points on both sides. It will be necessary to block one direction of the diagram, for which a fetal screen made of copper will be mounted; it will be located at a distance of 0.175 mm from the working wavelength. It should be placed on the cable braid.

Next, you need to test the antenna by connecting it to the modem.

Antennas for improving the quality of a mobile signal are different. They are sold in specialized stores and are easy to assemble with your own hands. In the second case, the quality of the Internet connection will not be worse, but will save money.

Mobile phone antenna

Phones operating on the GSM communication standard receive high-frequency ultrashort wave signals (900 or 1800 MHz). The higher the frequency, the further the transmission, but the less ability to bypass obstacles. This means that in built-up areas a signal with a frequency of 900 MHz works more efficiently. And in distant, spacious areas, for example, in the countryside, in a country house, a frequency of 900 MHz would be better.

Such an antenna for strengthening mobile communications is more relevant in the suburban area. Therefore, it is necessary to build a structure that will be calculated at a frequency of 900 MHz.

We obtain the wavelength using the basic formula: λ = 300/900 = 333 mm.

This means that the total length of the conductor is 333*2 = 666 mm. And the side size will be approximately 333/4 = 83 mm.

Modern mobile phones exclude the possibility of freely connecting an external antenna. It is possible to organize a connection only after disassembling the device. Therefore, the easiest way is to use the antenna in conjunction with an old phone that has a connector for an external receiver.

The first option is directional devices

When there is a signal on the 3G modem, but it is not strong enough, then you can get by with quite simple devices in order to achieve better quality of mobile Internet reception.

Typically, this measure consists of better positioning the modem and pointing its standard antenna in the desired direction (towards the tower). An ordinary tin can, an old pan, dishes, or even a simple disc may be suitable for these purposes.

For example, if we talk about a can antenna, then you only need to punch a hole at the base or in the bottom in which the modem itself would be securely attached. In fact, the signal should be significantly stronger if you choose the right direction.

An example of a homemade can antenna

Those who use old disks to amplify the signal do it even simpler. The main thing is that they are opaque. But you shouldn’t expect great achievements from this method.

If you need to make the signal a little better

No special engineering skills are required if you adapt old dishes to enhance signal reception. Colanders or saucepans with handles work especially well. Then you can attach a USB cable to the handle, and move the modem itself a little into the inside of the dish, something like this:

Another simple way to improve signal reception with a 3G modem

Characteristics of external amplifiers for the modem

Antennas are devices for amplifying a signal. They come in different types:

narrowly focused;
sectoral;
omnidirectional.

The simplest ones are omnidirectional. They can receive and transmit signals in all directions with the same intensity. An example would be a conventional quarter-wave vibrator. To put it simply, this is an ordinary piece of wire having a length of a quarter of the wavelength of the received signal.

Sectoral is capable of limiting radiation in a certain sector. For example, if you place a sheet of iron behind an omnidirectional antenna, you will get a sector antenna with a sector of 180*. Such a sheet of iron is called a screen.

The most effective is a directional antenna, which is a special case of a sector antenna. By selecting (of course, accurately calculating in reality) the curvature of the screen, you can obtain a narrowly directed beam of radio wave radiation.

The two main characteristics of any transceiver device are sensitivity and gain. Sensitivity affects the quality of the received signal, and the gain affects the quality of the transmitted signal. These parameters are measured in dBi. Sensitivity is measured as a negative number, gain as a positive number. The larger the modules of these numbers, the better, the better quality your device is. For example, sensitivity at -75dBi is worse than -83dBi. The gain of 11dBi is better than 6dBi. The higher these parameters, the greater the range of the established connection.

DIY Kharchenko antenna for 3g modem

Modern society cannot imagine its existence without the Internet. This network provides many opportunities that all people want to use, but do not always have such an opportunity. It is at such moments that the idea arises of creating antennas that can pick up signals even in the most remote places.

Antennas for 3g are only effective when made correctly. Sometimes you can see a variety of options. But why complicate the situation if you can make a simple option that can guarantee the end result. For this purpose, the Kharchenko antenna was invented.

Type and contents of the Kharchenko antenna

This antenna has the form of square elements connected to each other. That is why it is also called a butterfly. The manufacturing process is very simple. The basis of the structure is a wire that needs to be bent and the ends soldered. In this case, an angle is formed between the walls of the Kharchenko antenna, which is equal to 120 degrees.

For proper operation of the device, other parameters must be met: the side wall must be 5.3 cm long. The junction of the squares is 2 points, the distance between which is 5 mm. Under no circumstances should this parameter be changed.

Manufacturing

The aluminum plate should be 0.2 cm thick. You can buy it or make it yourself. To do this, we align the plate and make it into a square with sides of 14 cm.

We measure the center in order to drill a hole in it into which the coaxial cable will be inserted. It will be positioned in such a way as to reach from the wire element to the modem.

The wire is attached parallel to the plate using special holders made of plastic or other materials that are not capable of conducting electricity.

The Kharchenko antenna for a 3g modem with your own hands will not work without a cable, which must be passed through a hole drilled in the plate. Next, we connect it to the points at the junction of the previously made squares. All that remains is to connect the second part of the cable to the modem, onto which you need to put a piece of copper foil, and then wrap it several times and solder it so that the foil does not come apart in any case. Afterwards, you need to make a braid that would subsequently not touch the central core, which is connected to the foil on the modem. At the last stage, you need to check the signal level. If it is quite strong and without interference, then the Kharchenko antenna is made correctly

Characteristics of external amplifiers for the modem

Antennas are devices for amplifying a signal. They come in different types:

narrowly focused;
sectoral;
omnidirectional.

How to make an Internet amplifier with your own hands: diagrams

The cost of ready-made devices to improve the quality of the Internet connection is quite high. In this regard, a large number of users assemble amplifiers themselves at home. You can either convert a GSM repeater into 3G, or make it specifically for a network connection. But for this you will still have to purchase a ready-made repeater, since few people can make one from scratch.

Preparing for assembly

First you need to purchase parts and components of the structure:

wire, the total length of which should be about 35 cm;
a cable whose length depends on where the antenna will be installed. It is not recommended to buy more than 10m;
connection block;
fasteners for connecting several blocks together;
plastic.

Note! Scotch tape or electrical tape is also useful for gluing parts together.

Creating an Antenna

The antenna is assembled as follows:

You need to make a rhombus from the purchased wire. To do this, it must be bent in the middle at an angle of 90°. Then, at distances of 9 cm from the center, make two more 90° bends.
Bend the ends inside the rhombus and connect the connecting block.
Drill a hole in the polymer pipe.
Using a coaxial cable, which has previously been stripped of insulation at the ends, connect the antenna. Connect the conductors, both external and internal, to the contacts of the connecting block so that the cable becomes an extension of the antenna.
Installing the antenna on the roof and choosing the correct direction to the tower, testing the result.

Device creation process

When creating a vibrator, not only size, but also symmetry is important. 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.

How to make a Wi-Fi adapter for a TV or set-top box yourself

The pliers must be installed on the cable markings, 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 plastic bottle cap 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. This efficient installation method does not require electrical contact between the vibrator and the reflector.

Send data wirelessly

Electrodes must be connected to the starting points of the coaxial cable, which 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, insert it into the computer connector and evaluate the quality of the supplied network.

Antenna for 3g modem: DIY life hack

Many people in the modern world use the 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;
Connector for connecting the antenna to the modem;
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.

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 result 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:

Search 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; you can use foil or tin from a tin can if you have available materials;
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;
Thread 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.

Other homemade antenna options

Ideas for homemade antennas could be as follows:

4G mesh filter. Everyone has a simple aluminum colander in their home. You need to attach the USB extension cable to the handle of the cookware. Connect the modem to it - as a result, it should end up inside the circle of the bowl. We direct the colander to the base station and receive the signal.
You can amplify the signal using a regular hammer
3G/4G satellite dish. If you have an old satellite dish, use it. The signal will be significantly amplified since the antenna will be outdoors. Remove the converter from the shaft. Repair the modem at this location. Of course, you will need a USB extension cable - carefully stretch it to the modem and plug it in. Now point the dish at the operator tower. To adjust, you will need to rotate the platter slowly for maximum effect.
A satellite dish can quickly be converted into an antenna for 3G/4G
Double ring antenna. The method is similar to the Kharchenko antenna. This is just as effective, but even here you will have to work hard to make an antenna.
To assemble a double ring, you need to take four identical round metal plates and a large panel made of the same material as the reflector

Types of antennas for 3G and 4G

At the moment, there are many types of signal receivers for third and fourth generation mobile networks. Many of them were used even before the advent of cellular communications (for television broadcasting) and managed to prove themselves well. Below we talk about the main antennas for 4G Internet, which you can assemble with your own hands.

Simple

The most primitive type of antenna, which looks like an ordinary piece of wire. This device is classified as medium- or low-power. That is, it is unlikely that it will be possible to maintain long links with its help. But you can easily replace the standard antenna of a router or modem with 2 decibels. This will allow you to at least double the coverage radius of your network device without much expense.

Antenna soldered to the modem

Panel

Another option for equipment used to improve signal quality. They are especially popular for working with 3G and 4G networks.

Note! Initially they were used for third-generation standards, but then it became clear that these devices can easily work with LTE networks. The thing is that the working range of these standards partially coincides

Directional 3G, 4G gun

This device is a pin on which copper circles of a fixed radius are placed at a certain distance. The advantage of such a device is that with a competent approach and a minimal amount of money spent, you can get an antenna that picks up a signal even 30 km from a tower or base station, which is extremely profitable and convenient.

MIMO

To increase the capacity of data transmission channels between the receiver and transmitter, a special method of processing radio signals was developed, based on the fact that transmission receptions are carried out through various antennas.

Important! By using a MIMO antenna, you can increase the network access throughput. This will be a value that is on average 10-30% greater than when using a simple antenna

The basic operating principle of the device is to eliminate any connections between the receiving and sending antennas.

Kharchenko antenna, or biquadrat

An antenna that was invented back in the 60s. last century, is rightfully considered one of the most popular. In those days, it helped improve the picture quality on TV for people living outside the area of reliable television reception, and today it can easily increase the speed of access to mobile networks and telecommunication systems.

For your information! Its other name is biquadrat.

Wave

An antenna called a “wave channel” was invented even earlier, in 1926 in Japan. These devices immediately became popular all over the world. They are very easy to manufacture and have fairly good directionality. The television has become digital, which means that the multiplex can transmit several channels at once on the same frequency.

Important! This has greatly simplified the manufacture of the antenna, since now there is no need to provide a broadband signal, it is enough to create a receiver for one specific frequency

Other possible types

One of the most common types of antennas is a satellite dish feed. It is sold in many specialist places and is good value for money. Satellite dishes allow you to record a signal at a distance of up to 40,000 km. It is clear that making such a device at home is extremely problematic, so it is not worth a detailed consideration. If you wish, you can simply buy it.

Operating principle of a signal amplifier

Installation and connection

The connection diagrams for the finished antenna differ and depend on which device it is connected to.

You can connect the finished structure to the modem in 2 ways, depending on whether it has a connector for an external antenna. The task is simplified if there is one. In this case, you need to select a plug that matches the type of connector on the modem and solder it to the free end of the coaxial cable in the manner described in paragraph 4 of the instructions for assembling an antenna for digital TV. After this, all that remains is to connect the plug to the connector built into the modem.

The task becomes more complicated, but not much, if the modem does not have a connector. First, you need to disassemble the device to get to the printed circuit board. There will be a contact or track on it that acts as an antenna, to which you need to solder the central core of the cable. The braid is soldered to the modem body or to its grounding. To maximize connection speed, the structure should be rotated so that it faces the tower. All that remains is to connect the modem to the laptop and check the signal reception level.

Installation and connection to digital TV is carried out taking into account the polarization of the television broadcast wave. If the received signal is horizontally polarized, the structure should be rotated so that the vibrators are located vertically, that is, one above the other. If the polarization is vertical, the biquadrates are placed horizontally in the form of an infinity sign. The structure is directed towards the television tower. The antenna is connected to the receiver (receiver) using a plug.

To connect the “double square” to a cell phone, you need to remove the cover of the device and find a socket for an external antenna. The connection is best made through an adapter or antenna adapter, on one side of which there is a connector for connecting to the phone socket, and on the other side there is a standard high-frequency connector. The plug of the assembled antenna is connected to it.

Antenna for Wi-Fi.

Antenna design features

Decimeter version

A design feature of the Kharchenko antenna is a fixed ratio between the perimeter of each of its two squares and the length of the received waves (they must be equal)

To obtain the desired induced field strength, it is also important to select the correct diameter of the frame wire

Since broadcasting was previously focused on the meter range, receiving such a signal would require a wire with a diameter of about 12 cm. In this case, the zigzag antenna would be too bulky and inconvenient to use, and its dimensions would not allow it to be used at home.

Kharchenko’s zigzag antennas experienced their second birth at the time of the advent of broadcasting in the decimeter bands.

Additional Information. A zigzag antenna designed to receive a UHF signal must have fixed dimensions, which will be discussed in the following sections.

The characteristic impedance for which such home-made structures are calculated is usually about 50 Ohms. This indicator, however, agrees well with a typical coaxial line with a corresponding parameter of 50 (75) Ohms. To expand the bandwidth of the television signal, such an antenna was made not from a simple wire, but from a flat copper or aluminum bus, the individual parts of which were connected into a biquadrate using pre-selected aluminum rivets (photo below).

Tire product with rivets

At the junctions of the copper strips, the UHF antenna was additionally soldered; in this case, the distance between the rivets was taken as its length. In cases where, in order to obtain reliable reception, it was necessary to use a standard antenna amplifier, the developers did without the second square (one was enough for reliable reception).

Execution in the DVB-T2 standard

Digital broadcasting, designated by the “dvb t2” standard, is carried out, as is known, at UHF frequencies corresponding to TV channels from 21 to 69, using the “multiplex” format. In many Russian cities, local television stations are gradually switching to the dvb TV broadcast format, which is causing some interest in ensuring its reliable reception.

In this regard, the user must know that a homemade design for T2 must have the same dimensions as a classic antenna for UHF digital broadcasting.

Important! Modern television receivers, which include an antenna for a digital signal, can weaken it if the transmitting station is close. In special situations, when the transmitter for the T2 band is very close, when using the old frame design, you will either have to completely remove the second square (or screen), or choose a less sensitive amplifier

In special situations, when the transmitter for the T2 band is very close, when using the old frame design, you will either have to completely remove the second square (or screen), or choose a less sensitive amplifier.

The following solutions can be chosen as options for manufacturing a dcv structure:

Make a completely new receiver for t2 with your own hands;
Try to build a combined antenna containing an element in the form of a circle made of wire 55.5 cm long (see photo below);
With its help it will be possible to receive all known formats (including 3g mobile communications).

Combined antenna
The second of these methods for making an antenna for digital communications is discussed in detail in the following source https://elquanta.ru/antenna/kharchenko.html.

In the case when you need to make a structure for receiving Internet signals, including Bluetooth, WiFi (3g, 4g) or mobile communication channels operating on ultra-short waves, the dimensions of such an antenna will be very miniature.

Due to the high frequency, the dimensions of the antenna for 3g will be limited to a length of 10 centimeters, and all possible varieties of a homemade product can be assembled using the same drawing.

Significant differences regarding all possible versions of a miniature antenna (for Bluetooth or for a cell phone) will appear only in the dimensions of the receiving structure itself.

The calculation procedure in this case is determined by the method of using a specific network resource (these methods are widely represented on the network for both T2 and other TV signal formats).

What knowledge is needed for such work?

The science that considers aspects of this issue is quite complex - it is electrodynamics. And many students at technical universities even hate it and try to pass tests on it as quickly as possible.

But to understand the principle of operation of the antenna, you do not need to take the main course, you just need to understand the main principles.

One of these principles is that metal shields high-frequency signals. Therefore, a metal mesh of certain sizes in a reinforced concrete wall may also not transmit or significantly weaken the signal.

Description of a homemade receiver

With appropriate settings, this antenna is both an amplifier and a receiver. The inventor and scientist Kharchenko suggested using this biquadrat as an antenna. Biquadrat is a subspecies of loop antennas, which are primarily classified as zigzag.

K. P. Kharchenko proposed this device as an antenna in the middle of the last century (1961) for use as a television receiver. There is a good reason for this: it is a historical, recorded fact that, having tuned his antenna to a frequency of 14 megahertz and giving it the required position, the scientist received a signal from America.

Among the factory models of amplifier antennas, it is easy to find powerful devices with high performance. But quite often you can get by with a simple design that can be easily assembled from available materials with your own hands. It is enough to use the well-known development of Kharchenko.

According to the creator’s research, in terms of output parameters, the antenna reliably enhances the operation of digital devices operating on mobile platforms, generating an increase in signal reception of up to 3-4 dB, even without the use of a reflector, and with its implementation - up to 8-9.

What types of modems are there?

Modems are largely dependent on the network on which they operate. These can be GSM or CDMA modems. In different countries, modems have different frequency ranges. Therefore, it is necessary to find out what the frequency range is in this particular case.

In addition, modems can be with or without an antenna connector. But even if there is no such connector, you can still use it, but you will have to violate its integrity.

Required materials and tools

The Kharchenko antenna can be made from almost any conductor. Various craftsmen use copper rods, rectangular bars, and even rolled steel wire. Flat aluminum wire without insulation is widely used.

The advantages of this material are obvious:

copper is not subject to corrosion;
the wire offers an optimal balance between softness (easy to bend) and maintaining the shape of the made figure;
Copper can be soldered without problems, which will be especially valuable for beginners when securing cable ends.

To make an antenna with a deflector, you will need a number of simple tools and materials. A short list of what is needed looks like this:

wire of the required length and recommended cross-section, characteristics are determined based on the results of calculations;
wooden strip for attaching the deflector;
small pieces of insulating material (pieces of wooden planks can be used) to place the receiving circuit at a distance from the deflector;
pliers or vice for bending wire, hammer;
insulating tape;
soldering iron, tin, flux;
metal hacksaw or scissors.

To connect to a TV, you will need a cable of sufficient length and one F-connector.