Homemade antennas for 3G and 4G modems: whip antenna and Kharchenko antenna

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Alexander Korovaev 09/26/2019

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Living in big cities, as a rule, there are no problems with finding a stable Internet signal, but once you move away from the repeaters of the mobile Internet connection provider, difficulties arise.
To ensure that the signal at your dacha or in a country house is always stable, you need to make a powerful 3G/4G antenna with a range of 40 km.

Panel 4G antenna

To make the panel you need to prepare the following parts:

sheets of galvanized iron measuring 33.4 x 29 cm (for the panel) and 11.8 x 7.05 cm (for 4 patches);
copper wire with a diameter of 2 mm;
a circle of copper foil with a diameter of 21 mm;
4 pieces of thin foam according to the size of the patches;
glue for attaching patches to foam.

Patches are arranged in 2 rows of 2 pieces. 2 pieces of copper wire are soldered to them crosswise. A hole is drilled in the panel through which the antenna cable is threaded and soldered to the wire. The patches and the panel are connected to each other through the foam using glue.

The procedure for manufacturing a 4G panel antenna according to Soviet drawings under the code F-20 is presented in the video below. The following materials will be required:

rectangle of foil PCB 43 x 20 cm;
8 M3 bolts and 32 nuts for them;
transparent printing film for inkjet printers;
photoresist film;
reagents - soda ash and ferric chloride.

The antenna vibrator pattern is printed on printer film. The textolite is cleaned and degreased. A photoresist film is glued to it using a roller, onto which the template is applied. The photoresist is illuminated with an ultraviolet lamp for 5 seconds (the time is indicated in the manufacturer's instructions for the film).

The exposed areas are frozen, and the areas of the film where the light does not reach according to the shape of the template are washed. The surface is heated with a hairdryer and immersed in a solution of soda ash, in which, after 2-3 minutes, the unexposed photoresist is washed off with a brush. The board is then etched with a ferric chloride solution for 35 minutes and again immersed in an alkaline solution for 1.5 hours in order to wash off the unexposed photoresist film. After this, the vibrator is ready; it is washed with warm water.

In each of the 8 segments of the vibrator, holes with a diameter of 3 mm are drilled in the center. A reflector of the same size as the panel (43x20 cm) is cut out of a tin sheet. The sheet is combined with textolite. Using a drill with a diameter of 3 mm, holes are made in the same places as the vibrator. M3 bolts are inserted into the holes of the textolite board; on the other side of the panel, 2 nuts are screwed onto each bolt. Two nuts and the thickness of the textolite give the desired 6 mm between the vibrator and the reflector. The tin sheet is tightened with nuts.

A cable is soldered to the resulting antenna and connected to the Wi-Fi router via a USB port. The central core is attached to the vibrator, and the braid is attached to the reflector. The router board is connected using hot glue to the back of the reflector. The vibrator is coated with a special non-conductive varnish to prevent copper oxidation.

3G antenna assembly for 2100 MHz

For assembly you will need:

copper foil, thickness 0.3-0.5 mm
M6-M10 rod with a thread of at least 45 cm
12 nuts for rod diameter
Coaxial cable – 2 pieces of 10 meters each
Pigtail adapter – 2 pcs.
TV connectors – 2 pcs.
Screwdriver with drills
Soldering iron with solder
Scissors
Pliers

You will also need an accurate ruler, a marker and electrical tape.

Step No. 1 - preparing elements for the antenna

1 In order to accurately cut circles of the correct geometric shape, you must first center the workpiece, i.e. drill the centers of the circles, and use a compass to make markings along them.

2 Copper foil can be cut well with ordinary scissors. We take the dimensions according to the diagram in the photo below.

Accuracy with an error of no more than 1mm

3 Next, we mark the connection points between the antenna and the coaxial cables. To do this, we mark the penultimate circle R74 - we retreat 11 mm from the circle. You need to make 2 such marks, and they should be strictly perpendicular to the radius.

11mm – 2 pcs., strictly perpendicular to the radius

4 Using a screwdriver, drill holes in the R74 circle for the central core of the coaxial cable (2 mm). Then we place this circle on the R100 circle, and through the holes with a marker we make marks for the holes for fastening the TV cable.

It’s easier to mark in place

5 Drill the R100 and screw the connectors into the resulting holes as shown in the photo below.

Remove excess from the connector

We fix the connectors in the circle R100

Step No. 2 - antenna assembly

We try to make it without errors

1 Using two nuts, fix the R100 circle on the rod in accordance with the dimensions indicated in the photo above. Don't forget to tighten the nuts properly.

Tighten the end nut

2 In a similar way we assemble the entire structure.

Step No. 3 - connecting the antenna to the adapter

Putting the cables in place

1 Strip the ends of the coaxial cables. Insert into the prepared connectors. The central cores of the cables must fit into the holes (2 mm) of the R74 circle.

A little flux and solder

Communication range

The following factors influence the radio range:

Location of BS and MS and terrain.
MS power and sensitivity.
Power and sensitivity BS.
Antennas used on MS and BS.
The will of the Lord God (experienced signalmen joke that this is the main thing).

Typically base stations have a power of 20 - 30 W. Antennas are used either whip or directional. The sensitivity of base stations is -100 dB - 115 dB. The user, of course, cannot change or influence all these parameters. The output power of the phone is 0.3 - 2 W, sensitivity - 90 - 105 dB. The sensitivity of a phone is mainly determined by the technologies used to create low noise input devices. If in areas of reliable reception the difference in sensitivity and power between models is almost unnoticeable, then in an area of uncertain reception it can become critical. Often the handset shows the signal level from the base station as 1 - 2 cubes (on the scale), but cannot establish a connection: there is not enough power. And although the ETSI standard regulates the standard output powers for each class of phone, the actual value may vary slightly. Tubes from SAGEM, Alcatel, and Motorola have good sensitivity. And all old phones pass in terms of power, especially Motorola. All phase 2 phones have approximately the same power.

As for the terrain, waves travel better on flat terrain and along the river. The higher you are (within reason), the better the signal. The forest sometimes dampens the waves more than urban buildings.

DIY Kharchenko antenna for 4g modem

The device is named after the engineer who first came up with it. This powerful external antenna for a 4g usb modem is made by hand; the diagram for the desired option can be found on the Internet. We will give the simplest one.

You will need copper wire and a 2mm thick aluminum sheet. First you need to bend the wire so that its sides do not touch in the middle. And solder the ends.

A hole for the cable is drilled in the center of the plate.

Then the wire is attached to the platinum. It should not touch the reflector.

Distance 3.6 cm.

Next, it is attached to the satellite dish bracket or simply to a stick.

If the modem has a connector for an amplifier, then all that remains is to connect it. If not, then you also need to prepare it yourself. Need copper foil for printed circuit boards. Wrap the modem 2/3 of the way around. Solder the cable. Make a second layer. And secure it.

All is ready!

You can also read the review of 4g Mimo antennas and find out how to set up 4g on your phone.

How to make an antenna for modems

To create a Kharchenko antenna for a 4G modem with your own hands, as well as to amplify the 3G signal, you can get by with the smallest set of devices and accessories that any home craftsman has. Required:

a piece of copper cable (30 cm), you can take it from the store if necessary;
a small piece of coaxial TV cable (1−2 m);
plastic water bottle cap;
a tin, a piece of foil or a DVD that has exhausted its capabilities;
ruler, pencils or markers for marking;
knife or scissors for cutting cables;
pliers or small vice for breaking the wire;
soldering iron for connecting cables to contacts;
glue for plastics (any will do).

If there is no glue, you can make it yourself. To do this, you need to dissolve ordinary polystyrene foam at the bottom of a glass container with gasoline or acetone.

Antenna for the Internet at the dacha

The most common Internet option in rural areas is mobile. To increase the signal level and distinguish it from interference, owners of summer cottages use various types of antennas that allow them to establish uninterrupted radio communications. 3G and 4G coverage areas are available almost everywhere, but there may be problems with stable radio communication due to obstacles that degrade the signal.

The operating principle of all radio signal amplifiers is the same, but the design and technical characteristics differ from each other. Externally and in their use, they do not differ from ordinary television ones, they are only divided according to the power of receiving radio waves. The main characteristic of the antenna is the operating frequency. You need to find out which signal is the strongest in a particular place in order to determine the range of the radio antenna for the Internet in the country. A weak 4G signal can be preferred to a stable 3G.

Note! An external antenna for a computer for the Internet must be mechanically strong, resist wind, and be resistant to high humidity and temperature changes. To strengthen a weak signal, use a radio antenna that is pointed at the nearest base station

The higher it is raised above the ground, the faster the signal will be received. It is securely fixed in a position where signal reception is best, and it is easily accessible so that it can be corrected

To strengthen a weak signal, use a radio antenna that is pointed at the nearest base station. The higher it is raised above the ground, the faster the signal will be received. It is securely fixed in a position where signal reception is best, and it is easily accessible so that it can be corrected.

Moving the signal amplifier outside the building eliminates attenuation and reflections that are created by various parts of the house:

a powerful 3G/4G signal from a cellular operator’s base station is picked up by a radio antenna, which is located on the facade or roof of the house;
the signal is transmitted via cable to the modem, which is inserted into the router;
The router distributes the Internet via a LAN cable, Wi-Fi to the N number of subscribers.

Gain using a router/modem and external antenna

All you need to do to increase your 3G internet speed is install an external antenna and connect it to a compatible router or modem. The antenna is placed at the most reliable signal reception point, preferably in the line of sight of the base station. For summer cottages this is a special house or roof made of wood. In the city, it is enough to take the antenna outside: it can be mounted on a balcony or on the external wall of a building.

The antenna itself amplifies the signal and transmits it via cable to the router or modem. Coaxial cables such as 5D-FB, 8D-FB or 10D-FB are used to connect devices. Also in our online store you can buy a ready-made cable assembly with soldered connectors. It is advisable that the cable length does not exceed 5-10 meters. N-type or SMA connectors are often used to connect antennas.

3G routers have a slot for a SIM card and, as a rule, differ little from regular home routers in their wired Internet configuration. Most 3G routers on the market today support Wi-Fi and allow you to set up a wireless local area network. We recommend to our customers the Huawei e5172s-515 3G/4G router, which has proven itself to be a reliable and cost-effective solution for home and office use.

Huawei e5172s-515 3G/4G Router with Wi-Fi support, SIM card slot and LAN port for connecting to an Ethernet network

For best signal reception, it is recommended to use Astra 3G, Omega 3G or Omega 3G/4G all-weather panel antennas with gains of 17, 20 and 18–20 dB respectively.

Astra 3G panel antenna with 17 dB gain

A cheaper option is a set of a regular home router with a USB port and a compatible 3G modem. After connecting to the router, the modem is configured automatically and does not require user intervention. In the GSM-Repeaters.RU store you can purchase kits that have been tested for compatibility, for example, a 3G-WiFi router ZBT WE1626 with a Huawei e352 modem.

If a modem is used, then special adapters - pigtails - are added to the circuit.

Pigtails - adapters for connecting antennas to modems with CRC9 (left) and TS9 (right) connectors

Selecting and installing an external antenna

Our store recommends using directional panel antennas that are resistant to adverse weather conditions and extreme temperatures.

The cellular signal is vertically polarized, and if the antenna is not installed correctly, the call quality will be seriously degraded. As a rule, a polarization indicator (usually an arrow) is placed on the antenna body, according to which it should be placed in space. If there is no arrow, the name of the antenna can serve as an indicator of polarization (the inscription must be legible).

It is best to use a bracket for mounting, which will further simplify the alignment and alignment of the antenna. The antenna itself must be aimed at the cellular operator's base station. You can find out which operators operate in your region using the coverage maps on our website.

You can determine the exact location of the nearest tower by installing the OpenSignal or Netmonitor application on your smartphone. In addition, some modems, such as the Huawei e3372, can display the signal level in decibels.

The Huawei e3372 web interface allows you to view the current signal level in decibels (dBm)

OpenSignal and Netmonitor applications

OpenSignal and Netmonitor are smartphone apps that let you view your current signal strength in decibels (dB) and quickly find the nearest base station. Data on mobile operator towers is reintegrated by the users themselves, so the database is always up to date. OpenSignal is available for Android and iOS operating systems, Netmonitor is only for Android.

The signal level is measured in decibels - the closer the indicator is to 0, the better the connection. For example, -50 dB means a strong signal, and -110 dB means a very weak signal.

OpenSignal has an intuitive interface and uses a compass to automatically point you in the direction of the nearest base station. The Netmonitor application contains several settings and is intended for advanced users. Both OpenSignal and Netmonitor can view base stations on Google Maps.

OpenSignal (left) and Netmonitor (right) help determine signal strength and location of the nearest base station

It is recommended to use OpenSignal and Netmonitor to determine signal strength and antenna alignment. Knowing the signal level in decibels and the location of the mast, it is easier to select the necessary equipment for amplification and avoid errors during installation and configuration.

Sources

https://itmaster.guru/nastrojka-interneta/routery-i-modemy/3g-antenna-svoimi-rukami.html
https://Vpautinu.com/antenny/kak-usilit-signal-3g-modema
https://besprovodnik.ru/kak-usilit-signal-modema-3g-4g/
https://vc.ru/life/127519-kak-my-sotovyy-signal-na-dache-usilili-i-obrushili-internet-v-dva-raza
https://doorchange.ru/sovety/sozdanie-antenny-dlya-usileniya-signala-3g-i-4g-modema-svoimi-rukami-harchenko-provolochnaya-banochnaya.html
https://KakOperator.ru/lifehacks/kak-usilit-signal-modema
https://WiFiGid.ru/besprovodnye-tehnologii/kak-usilit-signal-sotovoy-svyazi
https://nastroyvse.ru/net/inter/kak-usilit-signal-3g.html
https://internetsim.ru/kak-usilit-signal-modema/
https://gsm-repiteri.ru/kak-usilit-signal-3g-svjazi

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What is the Kharchenko antenna and how does it work

The so-called Kharchenko antenna, which is intended for a 3G modem, is a homemade model. There is nothing particularly complicated about its design. The zigzag design was proposed by scientist K. Kharchenko back in the 1960s. Today it is quite popular among radio amateurs not only due to its simple design, but also excellent repeatability and broadband. This last advantage applies particularly well to the spiral design.

In terms of their design, models can differ quite significantly. Based on the size of the plate, the frequency of the structure changes significantly. At the same time, you need to take into account that homemade antennas may include objects made of plastic and metal.

The antenna for the modem comes in different types. The simplest one is omnidirectional. It can receive and transmit signals in all directions equally intensively. In particular, this could be a simple quarter-wave vibrator. To put it simply, this is a piece of wire that has a length of a quarter of the wave of the signal that is being received.

A sector antenna can limit radiation in a specific sector. In particular, if you place an iron sheet behind the omnidirectional device, you get a sector design. Its sector will be 180 degrees. Such an iron sheet is called a screen.

The most effective is a directional design. Thanks to the correct choice of screen curvature, you can create a narrow beam that will emit a radio wave.

The main antenna units are:

a vibrator that induces, induces, a wave of electromagnetic oscillations that are sent by the cellular operator’s transmitter;
a cable together with a matching unit that transmits the induced signal directly from the vibrator;
signal transmission unit from the cable directly to the modem input;
a reflector that eliminates interference as well as reflected signals to increase receiving power.

The DIY Kharchenko antenna is an excellent device for anyone who wants to have high-quality communications without having to spend large sums of money. It is very easy to make even for an ordinary person who does not have the appropriate professional skills. The result is truly excellent. This design will last for a long time.

Device and optimal dimensions

As you know, the 4G modem operates at a frequency of 2100 MHz. It is equivalent to a wavelength of 143 millimeters. Nowadays there are still models that are created at 900 MHz, and those that use a composite order, but they are already losing their relevance.

The key components of the amplifier are:

vibrator - waves of magnetoelectric oscillations are induced on it, which are sent by the 4G provider’s transmitter;
antenna wire with a matching element that transmits the induced radio signal from the vibrator;
block for transmitting a signal from the wire to the modem input;
a reflector that eliminates signal interruptions and reflective noise - it is needed to increase reception power.

Basic requirements for a vibrator

It is important to pay attention to the type of metal used. As a rule, copper or aluminum is used for the amplifier. In home situations, taking into account the small parameters of the vibrator, it is easier to connect the cable by soldering. For this reason, you should immediately focus on copper, without even evaluating a number of its other positive aspects.

A special role is played by the configuration and cross-sectional dimensions. It is recommended to construct a Kharchenko antenna from a wire with a cross-section of at least 5 mm² and a diameter of 2.5 mm, since these parameters, according to popular experience, are the most favorable. It’s worth mentioning right away that it is permissible to take a thickness of 2.3 mm with a cross-section of 4 mm², which will not significantly reduce the reception characteristics. If necessary, it is permissible to install with a cross-section of 2.5 mm², but this will already spoil the quality of the signal and increase its attenuation. Although for any specific case or area this may be quite possible, it should be approached individually.

To receive a reliable signal, you need to pay attention to the symmetry of the squares and the equal size of the side surfaces.

Cable selection

The main difference from standard antennas that a private master may encounter is the size of the wave resistance, and it can be 75 or 50 Ohms. To reduce power losses, it is more reliable to use a wire with lower resistance. It is more suitable in terms of electronic performance, is more consistent, and guarantees the least signal loss. However, when using one of these types of wires, it is better to more accurately select the mechanical dimensions of the vibrator for it. In this case, signal power leaks will be minimal.

Specifics of the reflector design

Any steel plate can serve as a screen. It can be cut out of tin or cut out with a grinder from an unnecessary aluminum pan. If there is no metal, then you can get out of the situation and take plywood or cardboard and cover it with foil. You don’t have to worry about the result—there won’t be a noticeable difference. In any case, the resulting structure will be able to block the moving wave background from different sides.

A used DVD disc performs well. You can increase its effectiveness by covering one side with aluminum foil. This option does an excellent job of reflecting waves. Its additional advantage is its aesthetic appearance and significant ease of work.

To use the disc, you just need to coat it with glue and fix it on the cap of a plastic bottle. You also need to adjust the distance of the vibrator from the reflector. This can be done using additional washers (you can take them from screws) or trimming excess thickness.

When assembling an amplifier, you need to pay attention to the parallelism of the areas of the vibrator and reflector.

Application of panel antennas for operation in 4G networks

An outdoor LTE panel antenna is most often used to improve the quality of data exchange in areas with poor reception.

Small dimensions and high technology make it possible to place a large number of elements in one housing, which is especially important when using MIMO technology

MIMO technology

MIMO technology allows you to increase the throughput of a data transmission channel to the maximum theoretically permissible value. This technique produces spatial encoding of the signal due to the fact that reception and transmission are carried out by different antennas. The main requirement for successful use of MIMO technology is that the coupling between antennas should be as weak as possible. Technical language says that the antennas should be weakly correlated.

MIMO antenna

Equipment that supports MIMO divides the signal into several streams, distributing them among users. If there are fewer users than the number of transceiver modules, then each client can receive a signal through several streams.

So the following happens:

Data transfer speed increases;
Noise immunity is increasing;
Traffic interception becomes more difficult.

MIMO technology requires both provider and customer equipment to support it.

Receiving and sending information in wireless communication lines

Radio waves, when moving in space, encounter various obstacles in the form of houses, trees and other structures. Obstacles along the way can reflect or absorb the wave, or do so partially. Sometimes the signal is split into several component parts. The nature of the interactions between the wave and obstacles along the way is influenced by the surface material, signal frequency and many other factors. Reflection during transmission causes time delays to occur. In addition, due to all these interactions, only a portion of the waves sent from the receiver reaches the end user. Therefore, one of the main problems of wireless networks is multipath signal propagation.

To solve this problem, the following technologies are used:

To determine the maximum throughput - C, the formula is used:

С= MB log2(1 + S/N), where:

For 4G cellular communications, namely LTE MIMO, it is possible to use 8X8, which allows you to achieve speeds of up to 300 Mbit/s. Even at a considerable distance from the station, the signal will be stable. Today MIMO 2X2 is more common. Always for 4G the number of channels must be even.

Antennas can be located on the same surface or be vertically spaced. In the second case, it is important to accurately maintain the differences in degrees indicated in the diagram.

Simple external 4g antenna with your own hands

When thinking about how to make an antenna yourself, you need to evaluate what raw materials are available in the house. If a consumer of Internet services has a case from a computer that has fallen into disrepair at home or in the country, you can use it as the basis for an antenna. You will need to purchase a USB cord for a signal amplifier and scissors for cutting iron from the store.

You will need to cut out a structure from the back wall of the case, which is based on a rectangle 24 (width) by 20 cm, from which a thin long part 7 (width) by 14 cm extends down. In this “leg” a square hole is made for the cable (2 by 2 cm), as well as holes for a thin metal bending structure (the dimensions of the latter are 23 cm long by 2 wide), cut from the same body, and for a locking bolt. The scheme for cutting the body into components is very simple; the corresponding marks can be made with a pencil.

Is it possible to use such an antenna for a Wi-Fi router?

The antennas listed above can easily be used together with a regular Wi-Fi router. The only thing is that for a quality connection, in some cases you will have to solder an N-connector to the end of the wire.

Some devices have connectors for external antennas, but sometimes they don't. In this situation, you cannot do without an autopsy.

DIY 4G LTE MIMO antenna

If suddenly in a village or country house the signal source is weak and cannot be detected, you can make a high-quality antenna with your own hands and significantly speed up 4G LTE Internet on a smartphone, tablet or modem. Device diagrams are presented above. One of them is sure to be suitable for certain conditions.

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.

Tools and materials

To independently manufacture a Kharchenko biquad antenna, named after the engineer K.P. Kharchenko who created it in the sixties, you will need a number of simple and affordable components. These tools and materials are used on the farm and sold in markets and stores. These include:

preferably heat-resistant reliable adhesive for plastic surfaces;
a piece of coaxial television cable from 1 to 2 m long;
soldering iron for soldering contacts and cables;
markers or pencils and a ruler for marking;
small-sized vice or pliers for breaking the cable;
a plastic cap from a mineral water bottle or similar container;
sharp scissors or knife to cut the wire;
30 cm piece of copper cable with a thickness of 4 mm2;
unnecessary or worn-out CD/DVD disc, or a sheet of foil or a piece of tin.

If there is a shortage of glue, it is not necessary to buy it; it will be enough to dissolve ordinary polystyrene foam with acetone or gasoline in a glass container.

Reasons for poor internet on your phone

If a user on his phone encounters problems with Internet speed, then this may be a consequence of certain factors. Some of them depend on the location.

If the connection speed is weak, then the reasons for this may be the following:

Exceeding the permissible mobile traffic limit, as a result of which the speed will be reduced until the end of the day or month by the operator, depending on the tariff.
Weak cellular network signal, as a result of which it does not pick up the 4G/3G network. Currently, the 3G coverage of mobile operators is quite good, in contrast to the 4G standard, which is still being introduced.
Uneven terrain in which the subscriber is located. Hills, mountains, ravines and forests, as well as all kinds of concrete obstacles, greatly reduce the quality of the transmitted signal.
Any operational errors, viruses or glitches.
Long range to the tower.

Important! An Internet antenna for your phone can help strengthen a poor signal if it is caused by long distances and uneven terrain.

What does the signal level depend on?

Before you boost the signal of a 3G or 4G modem with your own hands, it is important to understand the factors that influence this parameter. Let's highlight the main points:

High load on the base station. For best reception, try connecting to the Internet at night or early in the morning.
Network coverage. Each provider has strong and weak signal zones. In the latter case, you will have to buy a more powerful receiver or look for other methods, the best way to catch the modem. The average range of the towers is limited to 30 kilometers, but the best reception is achieved at a distance of up to five kilometers.
Receive the reflected signal. One of the main reasons for signal degradation is the reception of a “mirror” wave. Before arriving at the consumer, multiple reflections occur, which lead to a lot of additional interference. In such a situation, the Internet speed decreases, and the user ponders the question of how to strengthen and improve the reception of the 3G modem to increase the speed. In such cases, it may be necessary to install antennas or an extension cable.
Presence of obstacles. In the city, there are many obstacles in the way of the signal: electromagnetic radiation, solid walls, partitions and much more. The more such obstacles, the lower the quality of the service received. Natural elements of the landscape, such as mountains, have no less influence.

Other hardware or software problems cannot be resolved. So, when considering how to increase the signal of a 3G modem, you cannot exclude the use of additional software to check the quality of the connection and identify the reasons for the slow speed. For example, the quality of the service may be affected by one or more programs. To fix this, you can remove unnecessary software from startup, disable automatic updates, and download torrent files.

Protection

To protect from external influences, the remote antenna must be placed in a housing of suitable dimensions. The exit points of the cable and fasteners must be carefully sealed.

Important! The body of the structure must be made of non-conductive material. It can be polystyrene or polyethylene

The first material is preferable because it allows the body to be assembled by gluing and is sufficiently resistant to ultraviolet rays, low and high temperatures.

External devices are at their greatest risk during a thunderstorm. A lightning strike that hits an antenna can instantly damage the internal circuits of all equipment connected to it. Therefore, if there is a possibility of a thunderstorm, you should disconnect the antenna cable from the modem or router connector.

Homemade devices for increasing the received signal power can improve the quality of reception, the speed of reception and data transmission, eliminating additional costs for more advanced equipment.

Assembly of the structure

Next, we connect the antenna cable to the homemade 4G gun.

Please note: the central core of the cable must be soldered to the second disk. While the cable winding itself is attached to the first disk.

A bracket (from construction steel angle) is screwed to the stud so that the antenna can be attached to the facade of the house.

A homemade 4G gun must be installed in such a way that it is directed towards the nearest repeaters.

Characteristics of external amplifiers for the modem

The main parameters characterizing the operation of an external antenna should be considered susceptibility, which determines the quality of the captured signal, and gain, which describes the signal redirected by the device. Both of these quantities are supposed to be measured in dBi.

Important! The characteristic that describes how sensitive an antenna is is a negative value (as opposed to gain). What unites these quantities is that the large value of the modulus of the number is highly valued

For example, a sensitivity of -85 dBi would be preferable to -70. In turn, a coefficient of 10 dBi is valued higher than 5.

Settings

The setup method is similar to how a satellite dish is installed on a television satellite. On the Internet it's a little different. The plate must be directed lower. You may even have to point it down. This is due to the curvature of the reflection. To set up a satellite dish as efficiently as possible, you need to rotate it and use a special program to monitor how the Internet connection changes. Once you are sure that you have obtained the maximum value, the antenna must be fixed.

The external 4G antenna is fixed, now we can move on to the next step. Now it's worth experimenting with focus. For different modem models it is necessary to configure the converter holder differently. To do this, you need to change the focus position and monitor the quality of signal reception.

In order to correctly adjust the focus, you need to know that the modem antenna is on the opposite side from the USB. Of course, this is not the case on all models, so it’s worth disassembling it to understand where the receiver is.

If you have not achieved line of sight conditions, then you should raise the structure. Increasing the diameter of the mirror can also help improve signal quality. A 4G directional antenna is capable of picking up signals over a long distance. How is diameter related to reception quality? On average, a dish with a diameter of 1 m provides a fairly good Internet connection at a distance of 30 km from the station. To connect the modem to your computer, you need to buy a USB cable. What should it be like? Of course, you should use a high-quality cord, a small cross-section with shielding and ferite at the ends. You can also purchase several of these cords and connect them together, without losing quality.

It should be remembered that you will not be able to use a satellite dish for television and strengthen your Internet connection. Of course, you can attach the modem to a satellite dish to boost the signal a little. But it should be remembered that if the dish is tuned to TV, you do not need to turn it away from the satellite. A high-quality signal can be obtained if the satellite dish is configured for line-of-sight conditions.

What you need for high-speed wireless Internet

If you need to use the Internet outside the city and get a good connection speed,

You need to use the following set of equipment:

Modem.
SIM card with Internet access

Also, to create a more comfortable environment, you need to use a wireless router and a USB cable that will be used as an extension cord.

Types of external antennas by design

In this case, there are several possible options:

Parabolic;
Pin;
Sector antennas for 4G Internet;
Circular omnidirectional;
With wave channel;
Panel.

Note! Each external antenna for a 4G modem has its own characteristics

Directional antennas (“Wave Channel”)

A characteristic feature of such products is a narrow radiation pattern. The main purpose is to receive and transmit signals while maintaining one direction. Depending on the installation, the effectiveness of two important parameters is determined:

Radiation;
Reception of radio waves.

This type requires additional adjustment of special precision

It is important to ensure that you point to the desired station. Only in this case will the device be as effective as possible.

This is how any antennas work to boost 4G, LTE, 3G signals.

Note! Often such structures are also called beam structures. Other names:

Other names:

Yagi-Uda;
Christmas tree;
Wave channel. Another name is the MIMO antenna for a 4G modem with amplification.

Panel antennas

Such devices are among the most common for receiving and transmitting radio signals. A variety of directional models. But the radiation pattern of the panel ones is larger when compared with the previous type. Thanks to this, the process of setting up basic parameters is simplified. It is enough to correctly turn the device towards the base stations to get the optimal result from using the antenna to boost the 4G signal.

The products have three important advantages:

Broadband;
Versatility;
Supports all popular signal transmission formats.

The kit consists of an antenna array, which itself is essentially dipoles located one below the other in two columns. Horizontal spacing is the name given to the method of arranging parts of the structure in this case. In the direction to the base station, the signal quality is constantly improving with this organization. Dipoles can be positioned differently, depending on the polarization:

X-shaped in both columns;
Horizontally, with an inclination of 45 degrees;
Vertical.

Note! The 4G amplifier antenna frames are often combined into a single housing that looks like a flat panel. For this installation, the design received the name

Circular omnidirectional antennas

Suitable for use in conjunction with all current standards for data transmission and voice messages. Any modern technologies are supported:

LTE 2600;
UMTS-2100;
LTE 1800;
GSM-1800;
GSM-900.

In this case, you can refuse precise installation in the direction of one or another base station. This is the omnidirectional variety. But their gain remains quite low. Only in some cases will it allow you to increase the signal level from uncertain to stable for a 4G LTE antenna for a USB modem.

Whip antennas

A variety of circular omnidirectional products. An asymmetrical vibration system is the basis for these devices. It is made as a rigid rod made of metal. The round shape has become a distinctive feature for the radiation and reception patterns. When organizing communications between mobile objects, this design option is very convenient. The signal comes from all directions, no fine tuning is required.

Sector antennas

Note! They are used when a base station is deployed, which is characterized by a large subscriber base. Products are designed specifically for operator towers using sector organization

The basis is a phased array circuit, with the formation of a 60-degree sector.

One of the main features of the design remains DC closure. Therefore, sector options are allowed to be used even where particularly difficult climatic conditions exist. The need for additional means for water protection then disappears. Directional 4G antennas cannot boast of such advantages.

Parabolic antennas

A relevant option if the operator’s tower is located far enough - at a distance of up to 20 kilometers or more. The solution has not become widespread due to difficulties encountered with installation and settings.

Note! Powerful parabolic 4G antennas are offset and direct-focus in design

Other homemade antenna options

Ideas for homemade antennas could be the following:

Colander 4G. Everyone has a simple aluminum colander in their home. You need to fix the USB extension cord on the handle of the cookware. Connect a modem to it - it should ultimately be within the circle of the bowl. We direct the colander to the base station and catch the signal.
3G/4G satellite dish. If you have an old satellite dish, use it. The signal will be amplified significantly, since the antenna will be outdoor. Remove the converter from the boom. Secure the modem at this location. Naturally, you will need a USB extension cable - carefully stretch it to the modem and connect it. Now point the dish at the operator tower. To adjust, you will need to rotate the plate slowly to achieve maximum effect.
Antenna "Double Ring". The method is similar to the Kharchenko antenna. It is just as effective, but here you also have to work hard to make the antenna.

Making an antenna from a tin can

The advantage of this homemade antenna is its accessibility. You can find a loose tin can in every home, be it for coffee or carbonated drinks. It is better if it is cylindrical - without corners. The jar will be a kind of “hearing aid” for the waves. They will reach the bottom and be reflected from it. As a result, a standing wave will form in the bank.

What needs to be done with the can to make an antenna from it:

Let's consider the simplest option - without using wires. All you need is a bank and a modem. Remove the lid from the jar. We make a hole in the wall closer to the bottom so that the modem can fit into it.
We place the modem in the hole so that the back part with the built-in antenna is in the can.
We take a USB extension cable and connect the modem to the computer through it.
We place the modem with the can on the windowsill or closer to the window. We look at the number of divisions and adjust the position of the can with the modem to maximize the signal. Insert the modem into the hole

The disadvantage of this method is that it is not suitable for all cases, for example, if you live on the first or second floor and your house is located far from the tower. It can help you if the signal problems are not too serious. Thus, the antenna is easy to manufacture, but not as effective as, for example, the Kharchenko antenna.

A more complex variation of the can antenna - with a metal connector inside and a wire that extends from it:

You need to drill a hole in the jar for the connector. It is better to use a connector with a nut.
You need to solder a pin from a piece of copper wire to the connector, the connector is screwed into the can (you need to make sure that it has electrical contact with the inside of the can, because sometimes it is varnished).
After this, all that remains is to make a cord to connect the antenna to the modem.
A can antenna can be made with a cable

Technical data and characteristics

Depending on the range, radio antennas have different designs and dimensions. Designs of existing receiving and transmitting devices:

"wave channel";
pin;
Kharchenko zigzag antenna;
planar.

The directional “wave channel” has the highest gain among all known antennas. If the distance from the base station to the village is several tens of kilometers, then a parabolic antenna may be the only solution for mobile Internet.

The simplest type of pin is a vertical conductor mounted on an insulator and connected at one end to a receiver.

A panel antenna is a version of a radio antenna that catches a scattered signal. When there are any obstacles, this model is suitable for stable operation of reflected waves.

The universal model of the Kharchenko radio antenna, which can be made by hand, consists of two copper squares, 3.5-4 mm thick. Simple in design, the frame model creates an excellent reinforcing effect.

Depending on the connection method

SMA modification

Several conditions must be met for this modification of the antenna for a 4G router to work for the user:

3G/4G modems equipped with TS-9, CRC-9 connectors.
Models with SMA connectors through which external connections are organized. The modem is already built into these routers. All you have to do is insert the SIM card.
You will need not only the device itself, but also 2 cable assemblies with SMA connectors, up to 10 meters long. Then it’s easy to enhance the signal quality.
To connect the cable, it is recommended to purchase two special adapters or pigtails.

Note! The use of this technology is relevant if there are connectors where external devices are connected. You can also use adapters to connect to regular USB modems

But a high-frequency cable in such situations will be too expensive. And losses in signal quality will remain serious. We'll have to strengthen

You can also use adapters to connect to regular USB modems. But a high-frequency cable in such situations will be too expensive. And losses in signal quality will remain serious. We'll have to strengthen it.

BOX modification

The purchase of such products requires the presence of the following equipment:

USB extension cable.
Modems for outdoor antennas for 4G modems, supplemented with TS-9, CRC-9 connectors.

Important. At the rear, the device is complemented by a sealed box of small dimensions

Adapters for connecting to a modem are usually already built into this part. A modem with 3G/4G technology is installed inside the box, to the connectors of which adapters are then connected. The next step is to insert a USB extension cable into the box. Usually a special sealed lead-in is used. All that remains is to connect to the modem.

A universal WiFi router with a USB connector and 4G support is needed if you plan to use the Internet on several devices simultaneously.

If the user already has a 3G/4g modem, the BOX modification will be an excellent way to save money. Only the modem limits support from certain telecom operators. The overall stability of operation via a USB extension cable largely depends on specific models.

USB modification

This is a kind of ready-made complex that allows you to amplify signals that are transmitted according to conventional standards. The user does not need any additional devices; a standard set is sufficient for amplification.

Note. A universal 4G modem is already built inside from the start

But 3G standards are also supported. It is enough to connect a SIM card from any operator operating in Russia. After this, the device is connected to the computer. Another option is to use a router together with a USB cable 10 meters or more long.

Signal loss on cables when using USB modifications is completely eliminated, the connection is stable.

Note! Only Ethernet modification devices will be a suitable solution if the connection requires a cable longer than 10 meters

Ethernet modification

Another type of ready-made kits that amplify the signal for modern 3G/4G standards. The kit comes with a built-in 4G modem, which is complemented by a router with a POE adapter. This designation is a technology that allows you to connect regular Ethernet cables. Their length, at the user’s request, can reach 100 meters.

When the connection freezes, the device supports automatic rebooting. Characterized by compatibility with WiFi routers of almost any modification. The rating will help you make your choice.

Note! Signal loss on cables is almost completely eliminated, which already distinguishes this option from the SMA 4G antenna

Kharchenko antenna (biquadrat): simple step-by-step instructions

The scientist Kharchenko proposed this model of a loop antenna in 1961. It was used as a television receiver. The antenna is very effective: it acts both as a receiver and as an amplifier. It is broadband, capable of increasing signal power up to 3-4 dB in the absence of a reflector and up to 8-9 dB with a reflector (a metal panel that reflects the signal). It doesn't matter if it's 3G or 4G.

Its disadvantage is the complexity of manufacturing compared to previous homemade antennas. However, with the right desire, anyone can handle its creation:

First, make a figure eight from a monolithic wire with a cross section of 4 mm2. The squares should be as even as possible. There must be clear symmetry. To do this, mark the thread with a marker before folding. Then place the pliers on the thread marks. Now you need to bend the wire at an angle of 90 °. Use a square to get the exact angle.
Make a symmetrical figure eight from copper wire
Take an aluminum plate - 22 mm thick. Total area 140 x 140 mm. The plate will be a reflector (reflector). Drill a hole in the center of the plate (drill bit).
Secure the figure eight directly in the center of the reflector at a distance of 3.6 cm. The panel and wire should not touch each other.
Secure the antenna with wooden sticks on the sides
Drill holes in the reflector for the clamps, place the structure on the bracket (take it from the satellite dish).
Now you need to solder the cable, first passing it through the hole in the plate. Route the cable from the antenna to the modem
If your modem has an antenna connector, connect the cable to it using an adapter.
If there is no connector, use copper foil.
Make a hood based on the size of the modem. Attach the cable to the cap (it needs to be soldered) and put it on the device. If there is no antenna connector, use a copper plate to attach the cable to the modem
After connecting the antenna, adjust the signal - rotate until the maximum result is in the form of several divisions. They appear in the device's or your provider's proprietary program, which is downloaded and installed on your computer to set up the connection. Try placing the antenna at different angles, such as 45° or 70.

What types of 3G/4G antennas are there?

Antennas (both purchased and homemade) are divided into several types depending on several indicators. If we talk about the installation method, there are indoor or outdoor antennas. The latter are more effective because they work in open space, where there is less interference. They are suitable for those subscribers who live far from the tower.

Indoor antennas are not as effective as outdoor antennas

Based on the receiving signal, antennas are divided into broadband and narrowband. The first ones are more functional - they are capable of receiving 2G and 3G signals when, for example, 4G does not work.

Antennas are also divided into directional, omnidirectional and sectoral. The last two types are capable of catching signals from several towers at once. There are also conventional devices and MIMO antennas - advanced equipment with two antennas at once, which receive the signal separately from each other, but transmit the signal to the modem simultaneously. They can increase speed up to 100 Mbit/s.

The MIMO antenna essentially has two receivers, hence its effectiveness

Depending on the presence of an amplifier in the antenna, devices are divided into active and passive. Passive ones, where there is no amplifier, do not improve the mobile network signal as much as active ones, but they do not need to be connected to an outlet (the amplifier is powered by an electrical network).

Wire antenna

Another primitive way to strengthen a fading mobile network signal is copper wire. It needs to be wrapped around the bottom of the modem, where the internal antenna is located. About 20 - 30 cm of the wire should remain free. We bend this free piece - it should be perpendicular to the modem, that is, vertical. We place the modem with a homemade antenna on the window and connect it to the PC using an extension cord.

Make a few turns around the modem and straighten the cable vertically

An extension cord can be purchased directly with the amplifier - this will also help improve performance.

Device creation process

First you need to create a vibrator. Size and symmetry are of paramount importance. To give maximum symmetry to the installation, it is necessary to make all the edges of the squares absolutely identical. This can be achieved in two ways:

Be sure to pre-mark the wire with a marker;
apply a control template of a certain length.

In the first method, pliers are placed on the wire marking and the latter is bent at an angle of 90 degrees to control the bend along the square.

In the second case, it is necessary to separate a part of the wire on a scale slightly larger in size than the sides of the square, and then sharpen it with a file or coarse sandpaper to the control size. The completed template, together with the wire, is placed in the jaws of the pliers so that one end, simultaneously with the wire, rests against a solid plane, and the other converges with the output plane of the pliers. Also, to guarantee the evenness of the surfaces, you can make calculations online using the Kharchenko antenna calculator specially designed for such purposes.

After this, the vibrator is bent with manual effort, using a control template for each edge of the square. After the wire is completely bent, the remaining part is removed with side cutters. A verification measurement of the faces takes place, which ensures symmetry in the position of each side in the same plane.

Connection and signal transmission options

In the middle of the bottle cap, a hole is drilled with a drill or cut with a knife, slightly smaller than the diameter of the cable (to make the structure more stable). The end of the wire is inserted. After this, it is disassembled so that the central core with a place for tinning and soldering is exposed.

The wires are connected with any soldering iron (you can even use a homemade one). When soldering is completed, the cover is pulled onto the vibrator, moving along the cable.

The reliability of the connection can be increased by using glue and making small cuts in the plastic plug.

The DVD disc is inserted into the cable through the central hole and glued to the end of the plug. In this installation, the reflector and vibrator do not make electrical contact with each other.

The antenna vibrator assembled in this way, together with the reflector, guarantees good reception of the electromagnetic signal wave without contact from the transmitter and redirects it along the coaxial wire. Now all that remains is to redirect it to the modem.

Redirecting the 4G signal to the modem can be resolved in two ways:

make a direct connection of the coaxial wire cables directly to the modem board;
use the antenna made by Kharchenko as an intermediate amplification link and use it to transmit the received signal to the integrated antenna of the receiving device.

The first method, in turn, involves two solutions depending on whether the modem has a special connector for connecting to an external antenna or whether it is missing.

If there is a connector, this will save the amateur craftsman from solving additional problems. Then you only need to solder the ends of the coaxial wire to the second part of the connector and connect the antenna through it.

If there is no connector, then to organize a direct connection to the modem board you will need not only disassembling the coaxial cable, but also soldering the core conductor with the screen layer to the microcircuit tracks. This is a very complex and delicate technical work that must be performed accurately, safely and in full compliance with technology. Otherwise, the modem will fail, and then you will have to buy it again.

Send data wirelessly

Anyone can cope with this task. It will be necessary to solder electrodes to the output points of the coaxial wire - they will become a generator unit and will emit a generally accepted and intense magnetoelectric wave directly to the modem antenna. You need to make one turn with any thread along the outer contour of the modem body and measure its size with a ruler. After this, you need to add 5 mm and cut a couple of strips of 75 mm in length and 45 and 27 in width from foil or a tin can.

The wide part for the core core needs to be bent according to the configuration of the modem, and for the screen - in a semicircle, and then soldered to the Kharchenko antenna.

The electrodes need to be separated a short distance and directed in such a way that they produce and address the received magnetoelectric signal to the integrated antenna of the modem. Their best location can be found experimentally.

Now everything is ready. All that remains is to insert the 4G modem into the laptop connector, and then check the quality of the network.

Ways to increase modem signal strength

So, you are not satisfied with the speed provided by your 3G/4G modem. Let's look at what you can do to avoid the hassle of web browsing and streaming video (one of the most important indicators of the quality of your Internet connection).

Stick-rope method

The name should not be misleading. We will not beat or tie anyone up. This is the one that, due to its simplicity and accessibility, should be used first. It's about placing the modem at the highest possible height for your conditions. By stick here we mean an extension cord, and by rope we mean a high-quality USB cable, all-weather characteristics and a length of no more than three meters, otherwise data loss is possible.

All your expenses are the purchase of a USB extension cable, and choosing the modem itself does not seem too technically difficult.

But it is hardly possible to achieve a serious increase in the signal of a 3G / 4G modem in such a makeshift way. The maximum you can count on is 2-3 dBm. This is not so much, you may not feel such an increase in potency.

There is also a serious drawback of this method - by taking the modem out of the room to the street, you thereby significantly reduce its resource. And here no protection will help: we are unlikely to last more than a year, since it is not designed to work at low temperatures and high humidity.

Making your own antenna

We have always had artisans, and our country is still rich in them today. After we became interested in the production of terrestrial UHF antennas, our home craftsmen were able to quickly and painlessly switch to digital signal receivers. As for the effectiveness of this solution, it significantly exceeds the increase in the modem signal due to its higher position.

Instructions on how to qualitatively improve the signal of a 3G / 4G modem with your own hands can be found in large quantities on the Internet.

The method is more expensive than the previous one financially, but not to say much. Especially if you use scrap materials - and in a country house this usually does not happen. Of course, the better they are, the greater the increase in power you can achieve. If you choose a good design and do everything perfectly, your gain could be on the order of 6 dBm. Of course, such amplification cannot be called significant, and the stability of reception when using “collective farm” antennas leaves much to be desired. But it's still worth a try.

And one more thing: yes, it is possible to strengthen the 4G signal at the dacha or in a country cottage, but if the antenna design does not allow placing the modem in the house, then this method can hardly be considered satisfactory, since the viability of the modem will be greatly affected. And it's absolutely free.

But enough theory. We suggest trying to make an antenna using Kharchenko’s method - it is well known in the circles of domestic innovators. True, to achieve this miracle you will need certain technical skills and even theoretical knowledge (in particular, an understanding of the principles of microwave operation).

Kharchenko antenna circuit to improve 3G/4G modem signal

The required set of tools and materials is small:

pliers;
file;
welder with welding components;
wire 3 mm;
copper pipe.

We are sure that all this will be found in the house. It is important to adhere to the drawing with maximum accuracy - any errors in the calculations will lead to a sharp decrease in signal gain. There are also antennas on the market made according to this design, allowing a maximum gain of 20 dBm.

If you do this manually, you will have to count on lower performance due to the complexity of the amplifier manufacturing technology. You will also need special tools, such as crimping pliers, a clamp, cable adapters, and a piece of coaxial cable.

Reflector

The name, of course, is abstruse, but in fact, a reflector means any metal object that can amplify the signal of your 3G modem.

There is no need to talk about high efficiency, but the popularity and accessibility of the method is beyond praise. To enhance a signal that has temporarily disappeared or dropped to a critical level, you can use a regular mesh filter - it is probably also present at a rarely visited dacha. An optical disk, which can be found somewhere in a cabinet, pan, or even a tin can, will do. You will need to place the modem in the center of your makeshift spotlight. This device is capable of focusing an external signal onto the modem in the same way as a satellite dish in relation to the head.

It is important that such a device has circular symmetry close to ideal. The modem should be placed strictly in the center - a shift of several kilometers can dramatically reduce the effectiveness of the method, so it will take a lot of ingenuity to get what you want.

Under such conditions, such an amplifier is capable of “overclocking” the modem by 15-20%. And it's better than nothing.

But there are also disadvantages, including difficulties in ensuring ideal symmetry of the reflector itself and the location of the modem in it; such an amplifier takes up much more space, which limits its use.

Using factory outdoor 3G/4G LTE antennas

This method is the most effective, but it is also the most expensive.

Specialized factory external antennas can significantly increase modem speeds with signal gain of 20 dBm or higher. They are weather resistant and provide stable operation for many years.

If you choose such an antenna with the right characteristics, even a distance of 10-20 km from the nearest tower will not prevent you from enjoying download speeds of about 50 MB/s.

If you live in an area where the signal is so weak that it actually prevents you from using the Internet, then with the help of such an antenna you can ensure reliable signal reception by the modem, which will be enough to perform such simple tasks as surfing.

Depending on the characteristics and quality of manufacture of such antennas, you will have to fork out 1500-4500 rubles.

3G/4G repeater

This device works in tandem with an external antenna, providing even greater signal amplification, including through effective interference filtering. The repeater allows you to significantly increase the speed of the modem, and there is no compatibility problem - such devices are “omnivorous”, they are ideal for modems of all domestic cellular operators.

It is recommended to purchase a repeater not only in cases where the gain of an external antenna is not enough, but it is capable of optimally distributing a powerful signal, ensuring an even load on consumers.

However, the cost of such devices is quite high - from 15,000 rubles. Chinese goods can be bought at a lower price, but the quality is adequate.

So, we have looked at all the main ways to overclock a 3G modem yourself. Now it’s worth moving on to assessing the effectiveness of the above methods.