Replace the phone antenna with a more powerful one. How to make and connect an external antenna to a mobile phone. How does a repeater work?

Despite this, a number of countries have already imposed serious restrictions on the use of mobile phones by children.

Now - about the types of antennas. Currently, the following types of antennas are most common in phones:

Internal (Patch antenna, PIFA antenna), hidden in the body and invisible to the eye;
- a whip antenna or a shortened dipole (Stub antenna), sticking out from the body like a stump;
- retractable antenna, made of thin telescopic tubes and hidden in the body;
- combinations of the above antennas.

Internal- one of the most common and, perhaps, the most user-friendly antenna, is completely hidden inside the phone. It never breaks due to rough handling and has good technical characteristics. The only disadvantage of such an antenna is that when buying a mobile phone, you do not know exactly where it is located in the phone body. More on why you need to know this a little later.

Recently, another type of internal antenna has appeared - such antennas protrude slightly from the body, but are mostly located inside the phone. The need for such antennas arose along with the trend towards creating thin phones - you need to somehow build good antenna into a flat phone. However, it should be noted that a good small, flat and cheap antenna for a mobile phone has not yet been developed.

Short dipole or pin. This antenna has very good characteristics, is clearly visible, but inconvenient for the user. In terms of prevalence, it ranks first among manufacturers of inexpensive mobile phones, since this is the cheapest type of antenna. Such antennas are often and easily broken by careless subscribers.

Retractable antenna or telescope. In Europe and Russia, this antenna is now found mainly in old GSM phones. In CDMA phones, on the contrary, the telescope is used quite often. In Asian countries (Japan, for example) and America (for example, the USA), such antennas are still popular. Reason – excellent characteristics and ease of execution - all this is important for the manufacturer.

Such antennas often break and require delicate handling. It is necessary to remember that a phone with a telescope should (not all manufacturers, however, follow this rule) work perfectly, even if you do not extend the antenna completely out of the case. Many people don’t realize this and fully extend the antenna every time they make a call. In fact, by extending the telescope you only slightly improve technical specifications antennas and increase the signal level.

This usually helps only when working in an area of ​​poor coverage or weak signal level, and in the city it has no effect at all.

There are other types of antennas and even combinations of those already mentioned. Note that a mobile phone may have not one, but two main emitting antennas. For example, two antennas are installed in 3G phones (combined UMTS/GSM or CDMA/GSM). There is nothing bad about this, you just need to know where these antennas are located.

In addition to the main emitting antenna, a mobile phone may also have a Bluetooth (BT) antenna or a GPS antenna ( global system location determination).

The HT antenna operates at frequencies of the order of 2.4 GHz and the level of its radiation is hundreds of times weaker than the radiation of the main antenna.

Now let's talk about why you need to know where the main antenna (or antennas) are located in the phone.

First, knowing where the antenna is located will prevent you from accidentally grabbing it or touching it while talking. It would be nice if each manufacturer indicated the location of the antenna in the phone in the user manual. It would also be a good idea to indicate in the manual that touching the antenna during a call is not recommended. No, it's not dangerous, it's just that by holding the antenna while talking on the phone, you impair its performance. Without going into technical details, we can say that an antenna with a hand pressed to it can perform significantly worse in reception and transmission. This leads to the fact that the cell radius, i.e. The area where your phone works reliably is significantly reduced. In each specific case, everything will depend on the type of antenna, its location in the case and how much the owner of the phone interferes with its operation.

Moreover, if you interfere with the antenna while talking, your phone's battery consumption can double or more.

This happens due to a change in the power balance of the radio channel - the phone increases the radiation power as directed by the network controller.

Here are the final calculated data for a regular GSM phone. If you change the antenna characteristics by holding the phone incorrectly, then

The cell radius for your phone is reduced by up to 20%, and coverage by up to 30%, which can lead to a complete loss of connection; for example, you dial a number - everything is fine, start talking, touch the antenna - the connection is interrupted;
- your battery life during a conversation is consumed faster by 20-60%, i.e. Battery life is reduced by more than 2 times.

All this is especially noticeable outside the city, where the signals are weak, that is, at a great distance from the station mobile operator.

Moreover, when you simply press your phone to your ear while talking and hold it correctly, your phone's transmit and receive signal levels may deteriorate. Sometimes at times, if the antenna is bad. All this depends on the type of antenna, its location in the phone body and its proximity to the head, and the phone model. To one degree or another, all mobile phones are subject to this effect and do not think that by buying an expensive phone you will get rid of all problems. The degradation of parameters can only be checked in specially equipped laboratories.

A reasonable question arises: how to make calls correctly without compromising the quality of work? How to hold the phone if it's not next to your ear?

The answer is simple. You need to make calls correctly without pressing the phone to your head/ear or holding it with your hands. It is best to use Bluetooth or headphones, and keep the phone separately (for example, in a bag), away from metal surfaces.

Where can built-in antennas be located? “Stealth antennas” are located primarily on the top of the phone and are often very close, right next to the speaker that you put to your ear. Much less commonly, the antenna is located at the bottom of the phone. In some clamshells, the antennas are hidden in the middle - at the top of the keyboard compartment. Antennas are often located in thickenings of the housing.

Knowing where the antenna is located is useful for another reason - in this case, you will expose yourself less to high-frequency power (which is strictly not recommended, no matter whether it causes harm or not), or reduce the intensity of such exposure. Reducing the intensity is achieved simply by correctly positioning the phone relative to the head - the distance between the emitting antenna and the head/ear should be as large as possible. It must be remembered that by increasing this distance by just a few centimeters, you reduce the intensity of high-frequency irradiation of the head by tens of times.

No matter what they say about the dangers of cell phone radiation, remember the main thing - microwave radiation certainly will not bring benefits to your body.

It is worth adding that the operating frequencies of the phone are close to the frequencies of a microwave oven. This means that the physical mechanism of influence on biological objects is the same in both cases - internal heating of the tissue occurs and its temperature rises. Of course, the power of the phone is hundreds of times less than the power of the stove, but then you apply the radiation source directly to your head. Draw your own conclusions.

Nowadays it is impossible to imagine life without a mobile phone, but in some cases it becomes useless. No connection or very weak signal happens in basements, in cars, in areas far from the relay antenna or in a city where there are many high-rise buildings that dampen the signal. In these cases, you can use a ready-made additional device or learn how to make and connect an antenna to mobile phone with your own hands.

Before you start searching and reconstructing external antennas for a mobile device, you need to understand how a modern cellular device works. And it is a small radio station operating at different frequencies determined by the cellular operator. So, in the “transmission - reception” ratio: base station (BS) - telephone (MS) operates on 935.2–959.8 MHz, and telephone (MS) - base station (BS) - on 890.2–914, 8 MHz. The link relationship from BS to MS is called Down Link, and MS to BS is called Up Link.

Any providers limit the communication range of a mobile phone from a base station to a distance of up to 35 km. With this configuration, the number of talk channels reaches 8 and is the standard mode used in urban areas. While GSM provides a non-standard configuration with a communication range of 70–100 km (Extended Cell), but there are fewer channels - a maximum of 3. The latter mode is usually used in the coastal coverage area.

Which external antenna is suitable for a smartphone?

The quality of communication and signal strength are also influenced by location, terrain, weather conditions and time of year, sensitivity and power cell phone and the main antenna. Automotive or standard is installed outdoors, preferably on the roof of a building or car. Like a television, it must be directed towards the nearest base station. To do this, the device should be moved and rotated until the signal strengthens.

1. The wave one contains a traverse with perpendicularly located reflectors. Their sizes depend on the frequency, which is directly proportional to the wavelength. It has a clear advantage of signal amplification with rather small dimensions. The disadvantage is the need for precise guidance to the station.
2. Parabolic consists of a reflector and an irradiator. This design amplifies the signal quite strongly, but installation requires certain skills. The disadvantage of this antenna is zero efficiency with inaccurate tuning.
3. A flat panel is a flat small square with an irradiator inside a reflector. The advantage of the device is a wide range of directionality, which does not require precise aiming, but at the same time gives average signal amplification.
4. The pin design is a small vertical rod that is both an irradiator and a reflector. The advantage of the antenna is its circular directionality, which does not require precise installation on the provider’s base distributor. But there is a nuance: such an antenna should be placed so that there are no shielding structures between it and the base. It is installed where no special signal amplification is required.

How to connect an external antenna to a mobile phone

Typically cell phones are set to high frequencies. Therefore, the quality of the cable and its connection is of great importance for the efficiency of the external structure. It is best to use coaxial wire (RG-6 from reputable manufacturers) and a high-frequency connector. If there is no jack for attaching an external antenna, you can use a speakerphone. In this case, the antenna wire is connected to the speakerphone device, and the mobile phone is inserted into the socket of this device. You can also make 3-4 turns of the central core of the cable around the mobile phone, near the built-in antenna.

Of course, this method of using the phone is not entirely convenient and is limited by the length of the wire. But these inconveniences can be avoided by making the mobile device stationary.

How to make your own antenna for a cell phone

A quick antenna can be made from what you have in the house

1. Take a copper wire and bend it into a diamond-shaped figure eight with a side of 8 cm. Connect the antenna to the phone with a cable, having previously stripped its ends. In a horizontal position, attach to the ceiling where there is a stronger signal.
2. Use culinary foil, make a large “bag” out of it and put a mobile phone in it.
3. You can use an iron basin of a suitable size, using it as a parabolic antenna with a mobile phone in focus.

A home antenna that is mainly suitable for signal amplification. To do this you will need: pliers, pliers or a knife, a coaxial cable, soldering equipment, copper wire (8 cm) and an adapter for a mobile device (Chinese is possible).

1. Strip one end of the high-frequency cable so as not to damage the central core; it will be connected to the antenna. The other end is connected to the phone.
2. Solder the copper wire to the cable core so that the structure is strong and positioned vertically upward. Solder the same wire to the cable braid vertically downwards.
3. Fasten both copper wires to a small wooden board, insulating them in the soldered places.
4. Secure this structure to the roof as high as possible, and the other end antenna cable connect to your phone using an adapter.

IMPORTANT. The vertical and horizontal connection of the copper wire to the cable should be strictly observed.

A portable antenna is suitable even if there is no network at all.

This is a fairly simple device, but quite effective. This device can be used anywhere. To do this you will need: a radio antenna from an old tape recorder, a thin wire (0.5 m), a screwdriver, a soldering iron and a small washer.

1. Disassemble the radio antenna at the base.
2. Solder the wires to the washer.
3. Assemble the antenna base by attaching the washer with the wire.
4. Remove the cover from the phone and find a connector for connecting an additional antenna.
5. Strip the other end of the wire by 1–2 mm (no more) and insert it into the hole in the center of this connector.
6. Fix the wire on the phone and look at the network scale. The indicator should show 6 out of 6 sticks.
7. The mobile device cover does not need to be installed.

In addition to homemade antennas, you can use purchased repeaters, which allow you to make stable communications in any room and remote areas. But the cost of such equipment is quite high and comparable to the price of a good mobile phone, and more advanced solutions reach 2–3 thousand dollars. Therefore, at home you can always use cheaper and more readily available means of signal amplification.

Modern mobile gadgets are necessary communication devices, which it is no longer possible to do without, this technology has become so tightly integrated into our lives. However, even with full coverage, there are still areas where these devices may be located in a “dead zone” or have rather poor signal reception quality. As a rule, such places include not only suburbs, but also megacities, where signal transmission is interrupted by many high-rise buildings. To solve this problem, the easiest way is to use special devices - cellular signal amplifiers: external or internal. But how to make an antenna for a phone? This issue can be resolved by first understanding the features of their design.

An antenna for a mobile phone is necessary if the signal reception from the relay tower to the phone is of poor quality, which, as a rule, occurs due to the influence of a wide variety of factors. Before you start looking for a suitable additional antenna for your mobile phone, first of all, you should understand the principles of operation of cellular communications itself.

A smartphone is a full-fledged miniature radio station that receives and transmits a signal in a certain frequency range (determined by the provider providing communication services).

The signal transmission parameters between the base station (repeater) and the mobile amplifier are usually called “Down Link”, and from the smartphone to an external antenna – “Up Link”. Note that, as a rule, providers almost always provide for some limitation when transmitting a signal from a base repeater (up to 35 km). This allows you to create a configuration that implies the implementation of 8 channels for user conversations. Such parameters are provided by the relevant communication standards. GSM operators provide fewer channels for conversation (no more than 3), however, in this case the transmission duration increases and reaches 100 km. Often this cellular network configuration for an external antenna is used in the coastal part of the coverage area.

Features of choice

Not every connected mobile antenna is suitable for phones supporting 3G technology. There are many factors that affect the quality of the signal received from the base station:

• relief features;
• geographic localization;
• climatic conditions;
• technical characteristics of both the antenna itself and the mobile device.

The most preferable place to place a 3g antenna for a signal amplifier is on an elevation. This could be the roof of a building or a car, in the case of using external equipment for the vehicle.

It should be taken into account that it is recommended to point the amplifier for 3 or 4g towards the nearest repeater tower, which will help ensure better signal reception and transmission. The antenna placement is shown schematically in the figure.

Note! By installing a cell phone antenna for amplification, you can improve the quality of communication not only on mobile phones, but also on other devices: laptop, tablet, PC and TV. Then general scheme it will be more difficult. When improving the signal for all gadgets located at home, the power of the antenna, modem and adapter used in the circuit is of great importance.

There are remote models and equipment with a stationary device. There are options that connect to your phone and distribute a signal, like Wi-Fi. For amplification, you can use active repeaters and work with passive devices. The former additionally convert the signal, while the latter receive only due to their configuration.

In addition, there are several main types of devices:

• wave receiver;
• flat antenna;
• parabolic antenna;
• whip type antenna amplifier.

The design of the wave signal receiver includes the following elements: a traverse and reflectors located perpendicular to it. This type of external amplifiers does an excellent job of amplifying the signal, but requires precise tuning (pointing) of the device to the base station.

Flat outdoor antenna - this type of remote device has a fairly wide directivity range. The device consists of an irradiator, which is built into the reflector structure. To adjust the antenna, select the approximate direction to the repeater.

Parabolic external antenna is a device for outdoor placement, consisting of an feed source and a reflector. The use of such an amplifier significantly enhances signal reception, but installing a telephone antenna requires certain knowledge and skills. If installed and configured incorrectly, the effectiveness of using this device will be minimal.

A pin-type antenna amplifier is a rod that simultaneously plays the role of a reflector and an irradiator. The design of this antenna implies circular directivity. A prerequisite when using such an amplifier is the absence of shielding devices that interfere with the reception of signal transmission.

But how to connect the external and internal parts of the devices?

Connecting a mobile phone to an external antenna

To operate a smartphone's cellular antenna, a coaxial cable with a high-frequency connector is required. This is explained by the fact that most mobile phones operate in the range of such frequencies. Note that the efficiency of signal amplification directly depends on the quality characteristics of both the connector itself and the cable products used.

If the phone design is not equipped with a socket for connecting an antenna, you can use a speakerphone to solve the problem. In addition, you can use a method that is not very comfortable for the user by wrapping the mobile phone with several turns of antenna wire. Although in this case, using the device is quite inconvenient, nevertheless, this allows you to achieve good signal reception on the phone.

Important! When using any type of device, it is necessary that the antenna itself is located towards the repeater.

Diamond antenna, self-assembly

Often, users do not have the means or opportunity to purchase an antenna amplifier for a smartphone (they live in areas remote from large populated centers). In this case, a person interested in improving the reception and transmission of his mobile phone signal can make a design for the phone with his own hands. Moreover, even simple homemade products can connect well to the network and give the desired signal.

To create a signal improvement device with your own hands, you will need a certain set of tools and materials:

• pliers and a sharp knife designed for carefully removing insulation from cable products;
• the cable itself (RG6) for connecting the mobile gadget to the antenna and a copper wire (2 mm cross-section), its length must be at least 8 cm;
• soldering tool with solder;
• adapter for mobile device.

The procedure for assembling an antenna for a mobile phone:

• First of all, the insulation of cable products is stripped, while this work should be carefully so as not to damage the internal core, which will subsequently be connected at one end to mobile device, and others - to the antenna;
• the copper wire is bent at the ends so that it forms a rhombus at both ends;
• at the next stage, a copper wire is soldered to the cable core (strictly in the “up” position), the other part of the copper wire is soldered to the cable shielding (strictly in the “down” position);
• Next, the copper wire is attached to any surface of suitable size (a wide wooden plank is better), and one should not forget about the reliable insulation of all connections made during the assembly process;
• the final structure is placed on the roof of the building and securely fastened; the provided free end of the cable is lowered down and connected to the telephone using a special adapter.

Important! It should be borne in mind that observing the placement of the copper wire will help to significantly improve the received and transmitted signal, even if it is almost completely absent.

The self-assembled design of a diamond-shaped cellular antenna is a very simple to implement circuit that can be assembled by almost any user who does not have special knowledge and experience. The only condition for assembling a cellular connection with your own hands is the sequence of the above actions and the high-quality connection of all elements. The increase in signal is directly dependent on the quality of performance.

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Dense urban development, terrain, power lines and distance from transmission towers greatly affect the quality of signal reception, which can disappear at the most inopportune moment.

And today I want to talk about several ways to strengthen cellular communication on your phone with your own hands and how much they really help. But before you perform any actions with your device, you need to make sure that it is working properly.

After all, poor reception may be the result of a faulty radio module, unreliable contact with the internal antenna, or a broken firmware.

Making sure that your smartphone is working is very simple. It is enough to compare its reception level with another one that is obviously working, not necessarily of the same model.

If it is very different, then most likely the mobile phone is faulty and it needs a direct trip to a repair shop. But there is no need to rush. I had a similar situation with Lenovo 316i, when the level bars on the display constantly disappeared, while other mobile phones worked fine. For some reason I was guilty of buggy software.

And, of course, I tried to reflash it, but the result did not change. Having studied a considerable number of forums, I was inclined to conclude that the cause of poor reception may be poor contact at the junction of the antenna and the motherboard.

This is a common disease of Chinese gadgets. The next step I decided to take was disassembling it.

And in fact, upon opening the case, I discovered that the middle spring tongue on the board was slightly bent down and did not contact the antenna, which was a flexible cable glued to the cover.

Armed with tweezers, I bent it up a little, screwed everything back, put the SIM cards and battery in place and pressed the power button. After the system booted, all four bars appeared in the status line and this time they did not disappear.

Thus, having the skills and certain knowledge, I myself managed to repair my mobile phone. But let's now talk about methods by which you can significantly improve the quality of communication.

Software method for boosting cellular signal

This time we won’t disassemble anything, but install it on Android special application MTK Engineering Mode, with which we will enter engineering menu and change some parameters there. It is free and can be downloaded from the Play Market. Please note that it is only suitable for devices running on a MediaTek processor. You can find out which processor you have using the CPU-Z program, which you can download, again, from the Play Market. So, click on the program shortcut and immediately find yourself in such a menu.

Go to the MTK Settings tab

As a result, we will see on the display this window with settings, where we uncheck all the boxes. We leave only

• EGSM900;
• DCS1800;
• WCDMA-GSM-900.

Thus, we turn off unnecessary frequencies that are not used in our country.

We perform the same operation with SIM2.

Then go to “Select a network” where we select the GSM only item. This is the 2G communication standard, which originally appeared during the construction of telecommunication networks.

It has wide coverage across the country and handles voice calls very well. Select this tab if you do not use 3G Internet.

After these manipulations, your handset will work longer by disabling scanning of unnecessary frequencies and keep the radio signal more stable, since it will not jump between WCDMA and GSM standards.

Connecting a homemade antenna

Previously, cell phones had an external radio antenna or a connector under a plug located on the back of the case, into which any piece of wire could be plugged, which significantly enhanced reception.

Now everyone modern smartphones, to which, except for charging and headphones, you can’t connect anything else. But, if you take it apart, then inside, on the board, you can see a small golden cylindrical connector with a hole in the middle.

It is intended for network diagnostics and is used only in service centers. But, if you insert a small piece (no more than 5 cm) of thin insulated wire into it, you can observe a noticeable increase in the signal level.

Only in this case it is necessary to comply with some conditions. The wiring should not bend anywhere or touch live parts. You can carefully lay it inside the case, between the battery and the cover.

Again, this method is not suitable for everyone, since most devices are non-separable or do not have such a connector.

Repeater installation

This option is ideal for use in a country house or village, where, as a rule, the quality of communication is poor due to the remoteness of the towers.

Its operating principle is to capture electromagnetic waves, pre-amplify them and transmit them to the user’s phone. The system consists of a repeater unit, external and internal antennas. The disadvantage of this equipment is the expensive price of the device, the complexity of installation, configuration and a short range. But you can try to build a homemade installation yourself to amplify the signal.

To do this, we need a metal rod about 50 cm long, a coaxial cable, a piece of foil measuring approximately 100 by 40 mm, glued to plastic or plywood. It will be better if you have foil-coated textolite.

So, we bend our rod in the shape of a diamond and solder a cable to it, the other end of which is soldered to the foil.

We install our diamond on the roof of the house or on a pole, preferably higher.

Now let's check the amplifier. To do this, we place the phone close to the plywood and notice how much the signal quality has improved.

sticker sticker

Often on sale you can find a universal compact antenna amplifier, which is a thin self-adhesive plate with a special geometric pattern of metal tracks, which, according to the manufacturer, reduces the amount of interference and allows you to significantly strengthen the signal where there is practically no cellular communication.

The sticker is glued to the inside of the phone, under the battery. But in my opinion, there is no point in buying it. You can just as easily put a piece of foil under the battery and the effect will be the same.

Now, with the help of such simple manipulations, you can use your own hands, using inexpensive materials, to strengthen the weak cellular signal on your phone.

P.S. I am attaching a screenshot of my earnings in affiliate programs. And I remind you that anyone can earn money this way, even a beginner! The main thing is to do it correctly, which means learning from those who are already making money, that is, from Internet business professionals.

This is a post about a very simple DIY project. However, this is a necessary thing in extreme conditions. It has happened to everyone that in a certain place the phone has poor network reception. It would be necessary to somehow increase signal reception. But how? Can! We will make a universal antenna that will amplify the signal quite well. What you need to make it at home.

Attention! To avoid damage, do not use for experimentation. expensive phones! One of the comments under these recommendations: This thing where you stick a wire is called a network switch and it’s really connected to the antenna, but sticking wires or anything else there is a direct road to a repair shop, I won’t convince anyone; Yes, this method will strengthen the signal, but with a 50/50 chance you will fail the switch. And then your signal level will become much worse than it was before, the phone will work as if it did not have an antenna.

Firstly, the phone. We open the case, inside there is a special socket for the antenna. A piece of copper wire. Can be isolated. A nail or other metal rod. Tools: soldering iron, solder.

It would be easier to twist all the connecting elements. But it’s better to do it thoroughly. It is necessary to solder and then insulate well. That's all! The antenna is ready. We put the battery in and turn it on. Loading has occurred. We see only two network indicator sticks. Turn it off again. We insert the contact of the simplest antenna into the socket. We put the battery back. Turn it on. Now the indicator shows as many as 6 bars. Let's try to remove the antenna from the socket. Just one division. Now all that remains is to somehow aesthetically decorate the homemade product. The result was a phone with an antenna.

Another video about this method

I repeat once again, it is better to order a ready-made adapter; to make an adapter yourself requires a special tool and special skills. Kit for self-wiring of pigtail ms-156, costing 80 rubles (long and short, I recommend long):

Contains pigtail, sleeve, heat shrink tube and cap. In addition, each RF connector is designed for a specific type of RF cable. This particular pigtail is designed for medium:

Removing the outer braid:

We fluff up the screen - the outer braid:

We clean the central core:

Let's try on the central core:

Carefully solder the central core, it is important that the solder does not go beyond the groove. Don't forget to put on the sleeve and heat shrink so as not to over-solder. :)

We put on the sleeve:

We press it in. I overdid it and crushed the central contact - you can't do that, but it seems to work. The fact is that you need a special crimp in the form of a hexagon, but I crimped it with a regular crimp for contacts.

For dessert we apply heat shrink:

Testing and operating experience

To put it into operation, I had to work with a soldering iron :). For the desktop antenna, the cheapest adapter with ms-156 was purchased (once again I recommend the long one!!!), the second connector was bitten off and the wire was soldered to the board. For the wave channel, the cheapest adapter with RP-SMA was purchased (I bought SMA first, when I arrived I had to order the correct one), the second connector was bitten off from it and the ms-156 pigtail was soldered. Speed ​​measurement results: Smartphone built-in antenna:

Tabletop antenna:

Wave channel

The desktop antenna switched to 2g.

Comments. In 2g mode everything is slow and very sad; an external 3g antenna is of no use. An external antenna gives a tenfold increase in outgoing 3g traffic speed. The fact is that the Internet implies bidirectional data transfer. That is, the miniature two-centimeter built-in antenna needs not only to receive a signal from the OpSosa base station, but also to reach it in response. Now about the fact that with a wave channel the speed is half that of a desktop one. In practice, the speed of 3g Internet is not constant, this will be written in the next section; during subsequent measurements, the speed with a desktop antenna was also low. However, from operating experience, I will say that with a desktop modem, sometimes it switches to 2g mode, but the wave channel is stable at exactly 3g, the speed really fluctuates, but peaks up to 300-400 kilobytes/sec during the day. Thus, I recommend purchasing a 3g wave channel antenna with an rp-sma connector and an rp-sma to ms-156 adapter. True, you will have to tinker with finding the base station, that is, the antenna will need to be pointed exactly at the base station and fixed. A hole in the modem/phone case will have to be made in any case. The cost will be around 1000-1500 rubles.

The key to solving this problem is external directional or omnidirectional antennas. True, buying an antenna is not enough - you need to install and configure it correctly. Readers familiar with radio electronics will be able to independently manufacture and configure an antenna operating in the GSM standard. Today we will talk about the types of antennas and how to install and configure them.

Reference
Simply put, a mobile phone is a duplex radio station that communicates on different frequencies. There are a total of 124 frequencies in the GSM 900 standard. The phone, like the base station, can operate on any frequency determined by the operator.

The base station (BS) transmits and the telephone (MS) receives at frequencies 935.2 - 959.8 MHz. The mobile phone transmits and the base station receives at frequencies 890.2 - 914.8 MHz. The channel from BS to MS is called Down Link, from MS to BS - Up Link. Most operators limit the operating range of a mobile phone from a base station - 35 km, which is due to the peculiarities of the standard. Let us explain that in a standard configuration network, 8 time intervals (time slots) are formed in one frequency channel: one is service, and seven are conversational. It is in this case that the maximum communication range on each channel is 35 km. However, GSM also provides a non-standard cell configuration, in which the communication range increases by 70 - 100 km (Extended Cell configuration). Unfortunately, with this configuration the number of conversation channels is reduced to 2 - 3, which reduces the network capacity. It is not profitable for the operator to use this mode in and around the city. Sometimes this mode is used on the sea coast to create coastal coverage.

Thus, if you have a GSM 900 phone, do not try to establish a connection more than 35 km from the nearest base station. The maximum communication range achieved by me is 34 km.

Communication range
The following factors influence the radio communication range:

Location of BS and MS and terrain.

MS power and sensitivity.

Power and sensitivity 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. Sensitivity base stations is -100 dB - 115 dB. The user, of course, cannot change or influence all these parameters. The phone's output power 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.

Signal search
So, you are out of town and want to provide yourself with communications. Climb to the roof, attic, or highest point near the house or location you want. If your phone can catch the network, but at the limit (or unstable), you have every chance to improve the situation by using an external antenna. If the distance to the station is less than 30 km, and the network is not available, also try using an antenna. In the latter case, try to negotiate with the sellers to return the antenna if the experiment fails.

If the signal, although very weak, was still caught, dial any city number to check. If during a conversation, audibility is normal and the interlocutor does not complain about the loss of parts of your speech, then the energy of both lines (UL and DL) is balanced and you can use a standard antenna tuned to the middle frequency between the receiving and transmitting frequencies. If the interlocutor disappears from time to time, it is necessary to “strengthen” the downward direction from the base station to your phone. It might be worth looking for a phone with better sensitivity. But if it is difficult to hear you, you should strengthen the direction from your phone to the base station. Already at this stage it is clear that when choosing the type of antenna and its parameters, it is advisable to take into account the operator’s data and reception conditions.

In areas of poor reception, interference (noise) is often observed between channels with the same and adjacent frequencies. Unfortunately, the frequency resource allocated to GSM 900 operators in Russia is limited, which is why frequencies from different base stations with the same or neighboring signal strengths are often “visible” in areas of poor reception. Such frequencies create mutual interference that interferes with communication, and at certain signal levels communication becomes completely impossible. If a strong signal from the base station is recorded on the phone screen, but it is not possible to establish a connection, or it is possible, but speech disappears all the time, then you are faced with “strangers”. It is not always possible to “force” the phone to select a different frequency, but a special function Nokia phones- Netmonitor allows you to do this.

I encountered a similar problem at my dacha, which is separated from a large city by a fairly open space. The phone received neighboring frequency channels with levels of 70 dB, 73 dB and 72 dB, but the quality of communication left much to be desired. The only thing that saved me was the forced selection of another frequency channel with a lower level - 80 dB. However, with a limited frequency resource, even frequency rescheduling of the network does not always help. However, if your phone does not have Netmonitor, you can use an external directional antenna with a good radiation pattern. All that remains is to make the right choice.

Antenna selection
As already mentioned, external antennas allow you to increase the range and quality of communication. For telephones, external whip and log-periodic antennas, as well as wave channel antennas, are mainly used. Let us repeat that in Western Europe There are no areas of uncertain reception. Therefore, directional antennas for GSM 900 terminals are practically not produced. If a manufacturer offers a directional proprietary GSM 900 antenna, it is usually designed to work with operator repeaters.

In the CIS and Eastern Europe, directional antennas are made in a handicraft manner. In addition, there is not big factories in the Czech Republic, Poland and the Baltic states. A simple car magnetic antenna has a gain of 1 - 3 dB (1 - 2 cubes on the telephone scale), a wave channel - 7 - 15 dB (depending on the number of elements, build quality and antenna settings), which is already 2 - 3 cubes on the scale , and the log-periodic antenna is 7 - 12 dB. A car antenna is a vertical rod of 3/4, 1/2 or 5/8 wavelength. Even a simple car antenna, raised higher, can improve the situation with uncertain communications. The fact is that when talking on the phone, about 10 - 20% of the energy is absorbed by the user's body, therefore, by raising the whip antenna up, you reduce the influence of surrounding objects on it. I myself have observed how homemade, half-wave and vertical dipoles, raised to 5 m, solved the communication problem. Let us explain how such a dipole is made.

Rice. 1. Vertical dipole

We strip the white RG6U television cable from one end. We get the central conductor and cable braid. We solder a copper wire of any thickness about 8.2 cm long (for the 900 MHz range) to the central conductor and fasten it vertically upward. We solder a second piece of wire of the same length to the braid and fasten it vertically downwards (Fig. 1). We get something similar to the letter “T” laid on its side. (Television uses horizontal polarization, while GSM uses vertical polarization, so just such a dipole is required.) We connect the other end of the cable through an adapter to the phone. Be careful not to short the central core with the braid, otherwise the phone may burn out. Well, in 5 minutes we built a primitive antenna, not inferior in parameters to Chinese automobile ones.

Let me give you a story from my life. Arriving last summer on vacation in Crimea, I discovered that there was no reliable coverage on the base promised by the operator. This meant that I would miss a very important call. A reliable signal was found on the roof of the cottage, but the prospect of sitting there for two weeks did not inspire me. In 5 minutes I found a piece of the required wire (I used aluminum instead of copper). It took another 10 minutes to find a 5-meter piece of television cable from the neighbors. The Nokia 7110 has a mechanical switch for the external antenna, so I simply plugged the center conductor of the cable directly into the phone connector, and connected the cable braid to the metal rim of the phone's external connector. I mounted the antenna on the roof of the house and within 10 minutes, to the delight of my family and the envy of my neighbors, I was freely communicating on the phone.

As they say, let's go back to our sheep. First, let's use a car whip antenna ($5 - 10).

The main thing here is not to run into too bad quality. Having Netmonitor, it is much easier to check the antenna. When the car antenna is connected to the phone, the signal level should increase by 1 - 3 dB (for example, from -60 dB to -57 dB). As a last resort, the signal should remain the same. If, when connecting an antenna, the signal decreases by 5 dB or more, it is better to refuse the purchase. I would like to note that a good branded car antenna costs $40 and above. However, even among the Asian 10-dollar products there are sometimes some good things.

Installed on the roof of your “village”, a car antenna can solve your communication problem. If the gain of the car antenna is not enough, you can turn to others - for example, a common directional antenna - a wave channel. It looks like an ordinary television antenna installed on the roof of a house.

The wave channel allows you to get real gain up to 7 - 15 dB with an optimal radiation pattern. But it has a drawback - narrowband. The difference between the reception frequency and the transmission frequency in GSM 900 is 45 MHz, and the entire operating range is 890 - 960 MHz (70 MHz band). Achieve linearity or close to linear characteristic difficult in such a wide range. Therefore, it is desirable to make a wave channel depending on the frequency of the operator and a specific location and, depending on the situation, shift the resonance to the frequency of the ascending or descending directions. For greater broadband, you should use only a loop vibrator, matching it with a cable - for example, with a balun; You should also limit yourself to a small number of elements, say, 3 - 12, since if there are more of them, it will be difficult to tune the antenna without equipment, in addition, the operating range of the antenna is narrowed.

I had to deal with many handmade wave channels. I state: in most antennas the gain was less than 7 dB, some had resonance at frequencies of 700 - 800 MHz instead of the GSM range and the gain standing wave more than 3 (during transmission, this can easily damage the output stage of the phone). Professionally manufactured and tuned homemade antennas were rare.

Now the next step is log-periodic antennas (they can also be found on the radio market). Compared to the wave channel, they have a wider operating range. Therefore, such antennas are less critical to the accuracy of manufacturing and tuning. The actual gain here reaches 10 - 14 dB.

Theoretically, if necessary, you can connect 2 wave channels, one tuned to the receiving frequency, the other to the transmitting frequency, but this is already too complex a system.

Cable and antenna adapters
In the 900 MHz range, the issue of cable selection becomes paramount. Domestic television coaxial cables can only be used to a limited extent (the attenuation of more than 30 dB per 100 m is too high). Of the available imported samples, RG6 is a suitable double-braided coaxial cable. You will find it in any store. The attenuation is 20 - 24 dB per 100 m (tested experimentally). Industrial pins car antennas typically include RG59 cable with an attenuation of 28 dB at 100 m. A wave channel antenna with a gain of 12 dB and 10 m of RG6U cable give a total gain of 9.6 dB, and at 20 m - 7 dB.

Most phones have a connector for an external antenna. In addition, for each type of phone there is a so-called antenna adapter (about $5), it connects to the specified connector and is a short piece of cable, on one side of which there is a specific telephone high-frequency connector, and on the other - a standard RF connector. Typically, the attenuation in the antenna adapter does not exceed 1 dB. When purchasing an antenna adapter, make sure it is functional. When you plug the adapter into the phone, the antenna built into the phone is turned off and the output stage switches to the adapter. In other words, if you simply connect the adapter to the phone, the signal on the phone's dial should drop slightly. Then you connect an external antenna to the adapter and the signal increases. If everything goes this way, then the adapter is working.

Setting up the antenna on site
So, you bought an antenna and connected it to the cable and to the phone. We climbed to a high point and began setting up the antenna. Place the phone so that the screen is visible. As already mentioned, when setting up an antenna with Nokia devices, it is best to use the Netmonitor function. In most other phones, you can enter a special code and open the service menu, which allows you to see the receiving level of 6 - 8 frequencies received by the phone in descending order, frequency numbers, distance to the base station, percentage of errors in the channel, etc. (For a description of many service menus, see . at: www.3ton.com/gsm.) If Netmonitor is available, we will focus on the signal level in decibels (remember that the signal is stronger when the level value in decibels is lower). If it is missing, we will tune according to the standard signal scale.

Since the antennas of GSM 900 base stations are vertically polarized, the wave channel should be placed vertically. When adjusting antennas, please note that the receiving signal level displayed on the phone changes with a delay of up to several seconds, so the antenna should be rotated slowly and discretely. If you know the direction to the nearest city, start there. Slowly turn the antenna horizontally. If a signal is found, your task is to find the direction from which the signal comes with the maximum level. If there is no signal, slowly turn the antenna horizontally until it appears. Remember that every meter of antenna installation height can be decisive. If no signal is found, try moving a few meters to the side and searching again. Maybe you'll get lucky.

It is not advisable to use a cable between the antenna and the telephone longer than 30 m: in this case, almost the entire signal is lost in the cable.

Finally, we present the dimensions of a homemade log-periodic antenna for the range 850 - 950 MHz (Fig. 2). Dimensions taken from the website www.atnn.ru. The program for calculating the antenna-wave channel can again be found at: www.3ton.com/gsm.

This video tutorial shows how to connect an external antenna to a smartphone. How to solder a connector for an external antenna to a mobile phone. A fly brand smartphone is used. The modem is already soldered. A 50 ohm low attenuation cable is used. It is inexpensive and can be found in any radio store. The connector used is a 75 Ohm cable connection. Designed for a larger diameter, you have to put heat shrink on the end. Initially I wanted to use other connectors. Made in the Soviet Union, very high quality, plated with technical silver. However, it’s massive, so there’s no point in attaching GSM equipment to it.

It is unlikely that much effect will be achieved in the field of strengthening communications. There are many articles on connecting an external antenna to a modem, but according to the recommendation of the developer of gsm equipment from 800 megahertz and above, it is recommended to use only active antennas with a cable length of more than 10 cm. It is clear that if the plug is sealed, then there is already more than 10 centimeters. It is difficult to make an active one at home. We'll do the usual one. But this is not the topic of the video lesson. Today we’ll just solder the connector, and we’ll carry out the test in the wilderness, where there’s practically no mobile communications.
Video from the channel “Automation, Instrumentation, Commissioning”.

The GSM standard was invented by Europe in 1982, along with several related to communication via radiotelephones. The direction of the antennas was problematic; the transmitters were located near the person’s head. The harm was noticed quickly, it is widely known: employees of enterprises involved in communications receive bonuses wages. Without thinking twice, the standard committee introduced a new type of modulation that allows for lower power. The antennas were first made retractable, but later they took on the appearance of stumps protruding from the body of the device. The filling rapidly decreased in size along with power supplies; the direction of small-sized antennas in the gigahertz range is relatively young. The first developments concern the 50s of the last century. Do-it-yourself GSM antenna: how to make it, where to install it. Let's talk in more detail.

Development of the GSM standard, GSM antennas

Those who bother to look inside a mobile phone or other gadget are powerless to see structures that resemble an antenna familiar to the eye. A thoughtful manufacturer designs, guided more by experimental considerations, devoid of a coherent theory. There is no point in thinking that a review will reveal the company's corporate secrets. Since 3G, digital standards, there has been a constant struggle to accommodate more information using fewer resources. They mentioned the harm, inside the cell phone the emitter is located in the rear wall area, separated from the user by a ground screen. Microstrip technology has been known for a long time. Veselov’s book from the 80s describes the concept in the third part.

Antenna efficiency GSM cellular phone is low, reaches 40%. Ordinary television ones sometimes go over 90. However, people don’t care; the harm to health is minimal. Every marsh sandpiper praises a cell phone, hears the interlocutor perfectly, and when the opponent’s connection is lost, the sound disappears... This means the cell phone is bad. The radiation pattern of the GSM antenna of a cell phone is one-sided - it does not shine in the direction of the speaker - it is greatly distorted. The user changes the balance of power with his hand, let alone obstacles! A GSM antenna is made by hand to improve reception by stationary objects. Mobility is limited to use by auto repair shops.

GSM antennas of transmitting stations are well equipped and emit excellent radiation. We hear the interlocutor (if he does not make sudden movements), the opponent will lose packets while jogging or in transport. The phone receives 5 stars and transmits much worse. Incoming packets with the opponent's voice arrive regularly, outgoing packets fail.

Now readers know: it is not possible to make a GSM antenna using microstrips yourself at home. Famous companies are fighting to solve the problem. Assembly and functional design takes minimal time, production is cheap. The layout of the internals (the antenna is not easy to fit into a modest space) is much more complicated.

The following standards are in use in the Russian Federation:

1. GSM 900: transmission frequency 890 – 915 MHz, reception frequency 935 – 960 MHz.
2. GSM 1800: transmission frequency 1710 – 1785 MHz, reception frequency 1805 – 1880 MHz.

A microstrip antenna consists of an emitter, a dielectric substrate, and a conductive screen. As the thickness of the emitter increases, the operating range, a tenth of the wavelength, increases. The dielectric thickness is less than the specified value. We are telling this for a reason. In the Wi-Fi range, microstrips are combined into grids, sealed with a plastic case, equipped with a single screen, and act as a single command, allowing for good amplification and, therefore, to catch a more distant signal. The towers are stationary and in direct visibility. If what is said is true for a specific situation, the solution is suitable.

Here is a picture (from the website http://www.carookee.net/) of a 2.4 GHz antenna. To start working at a frequency of 1800 MHz, you need to increase the dimensions proportionally in the ratio of 4 to 3. Please note, this applies to all lines, including connecting lines. First try the functioning of one square before reducing the getinax board to the sacrifice of the needs of mobile communications. The scale of the portal is wrong - see the picture with dimensions, arrows are shown. Image taken from http://www.zero13wireless.net/. The numbers are in millimeters. Proportionally remove drawing number one, determine the dimensions. The areas are square; if they are distorted, correct them with a graphic editor; even Paint, included by default in Windows, will do.

For other frequencies, feel free to extrapolate the drawing to all cases in proportion to the wavelength ratio. Divide 2400 MHz into the standard GSM band. The ratio 2400/1800 was taken above. By doing this, readers will choose required device GSM antennas. Containing 4x4 squares gives less gain (amplification of the GSM antenna signal), and is easier to point. The reception is blurry, it is unclear where the signal is coming from, the design is in place. In the case of a distant tower, clearly visible on the horizon, 9 squares would be appropriate. Please note that the feeder to the telephone (another receiving device) should not be long; the signal will fade on the way here, in the cable. I would like to place the device on the roof... assemble an amplifier using microstrips, buy a ready-made one in a store for required frequency. Find out the required number from your mobile operator. A state frequency service has been created, ask officials to talk to private owners.

Manufacturing of GSM antenna

Most readers have understood how a homemade GSM antenna can be made. The craft will require a getinax board of a suitable size with double-sided foil. Copper is applied on one side - it will be necessary to add a reflector structure from a sheet of steel or another metal with an area larger than the emitter. Then the copper is lined with the future contour of the antenna. Do it more carefully using a ruler and a corner. Then:

• The area under the antenna is covered with varnish, suitable for women's nails. The composition should not get on the surface in other places, on the joints; you can paint over large islands, then peel them off with a knife (to increase the processing speed).
• The boards are etched with copper sulfate. The foiling is double-sided - the back is completely painted over with varnish. Otherwise the screen will not dissolve! It’s just that the etching will not end in a conceivable time. Copper sulfate is not enough. The second side is not needed - tear it off with a knife. To preserve the screen you need to paint it with varnish.
• Etching is carried out until unnecessary areas of copper are washed off, the finished GSM antenna is washed with water, dried, and problem areas are cleaned with a knife.
• The product is placed inside a sealed plastic case, suitable size on racks that do not affect the metal part. The screen needs to be grounded. Try putting it on braid coaxial cable. We remind you: for WiFi, a wire with a characteristic impedance of 50 Ohms is used. How much to take for cellular communications: 50 seems appropriate because 900 MHz television is running out.

Types of GSM antennas

They wrote a lot about antennas for WiFi, readers guessed: the ranges are very similar... just take the drawings, transfer them to other frequencies, the dimensions are indicated everywhere in relation to the wavelength. Transpose sketches proportionally. The procedure is indicated above. It’s easy to find on the Internet the so-called Kharchenko antenna (biquadrat), which is a pair of frames with one common point. More advanced solutions were presented, characterized by greater amplification.

Readers will have a choice of which remote GSM antenna will be manufactured. Kharchenko's biquad design is made by radio amateurs from strips 10 mm wide, with a square side in the center of 80 mm. The dimensions were not checked, the dimensions are determined by the wavelength used by the GSM standard. For 900, 1800 MHz the difference will be two times. Check the dimensions of the drawings carefully. The frame must be proportional to a quarter of the wavelength. The formula is known from a physics course; there is no point in presenting four drawings that differ in small details. You need to understand: an external GSM antenna is similar in structure to WiFi, we believe that any of the sections can be moved here. The difference is limited by frequency, modulation. The first does not affect reception, the second determines the size of the GSM antenna.

When using an extension cord, try to place the amplifier close to the mounting point. Wire noise greatly reduces the sensitivity of the device.