Weak antenna signal on Android. How to strengthen a phone signal: reasons for a bad signal and solving the problem yourself

Despite the widespread use of mobile communications, the question of how to strengthen the signal of the phone, or rather the cellular network to which it is connected, is still relevant. It doesn’t matter whether you live in a small village or in a metropolis, the likelihood that your device will stop receiving a signal is everywhere.

This problem is gradually being solved by operators, new base stations are appearing, and communications are improving. What if the problem lies with your phone and not the network? Today we decided to figure out what is causing the poor signal level and whether it can be fixed with our own hands.

What is a cellular signal?

The principle of operation of cellular communications is quite simple: there is an operator’s base station and your phone, a radio frequency channel is organized between them, through which SMS messages are transmitted, calls are made, and Internet data is exchanged.

There are several cellular communication standards, differing in the method of signal transmission and frequency. As a rule, base stations are built at higher elevations in order to provide maximum coverage area. However, there is no escape from the obstacles that prevent the signal from passing through. These can be walls, trees, and other obstacles, upon contact with which the signal weakens.

It is clear that in open areas where high-rise buildings do not abound, the coverage area will be higher. For example, for stations operating according to the GSM-900 standard, in this case the zone is no more than 30,000 kilometers. In urban areas, the figure decreases to 7 kilometers. Stations with more advanced communication standards such as 3G and LTE cover an area half the diameter.

Why do we have a weak phone signal?

Due to the above-mentioned obstacles, so-called dead zones or holes in the coating may form. That is, places where the signal is weak, unstable or completely absent. Where you most often encounter poor signal levels on your phone:

• places located at a significant distance from the nearest station (there is simply no coverage);
• basements, underground parking lots, lowlands (the signal simply cannot penetrate here);
• hills, skyscrapers (often “going higher” does not necessarily mean the presence of a signal - above the 12-14th floor there is often no signal at all);
• buildings made of metal structures that do not transmit signals.

However, obstacles and distance from the station are not always the reason for the lack of signal. Often the cause is the user's phone. You've probably been in situations where a friend has a cellular signal, but you don't.

And this is despite the fact that you are using the services of one operator. There are common cases when two identical phones have different signal levels. There can be many reasons:

• a phone in a metal case or in a metal case can catch the network much worse than a plastic device;
• quite often, no matter how surprising it may sound to you, the cause is the “clumsy” phone firmware;
• damage to any components as a result of falls, immersion in water, etc.;
• The phone may have a defective antenna from the factory, which is especially common among Chinese manufacturers of inexpensive models.

How to boost your phone signal with your own hands?

Well, we've covered the theory, let's move on to practice. We will look at several ways to boost a cellular signal, from the simplest to the rather complex and expensive.

The reason is in the firmware

It's worth starting by checking that the software is working correctly before trying to get to the inside of the phone. Hundreds of users are experiencing deterioration in the communication signal that appears after flashing, so it’s worth paying attention.

We have already written, so we will not repeat ourselves. Firmware is a fairly simple process, but with its own nuances. The main thing is to remember to make backup copies of important files.

If the flashing helped, then we congratulate you, but if the phone still has poor network reception, then move on to the next point.

The signal is poorly received due to damage to the phone

As already noted, often the phone does not receive a signal well after it accidentally fell on a tile or plunged into the sea. In this case, the average user has no choice but to go to a service center.

Modern phones are quite complex devices, so for most people it is not possible to identify the source of the problem on their own. It is likely that specialists will detect damage and carry out the necessary work so that your phone can once again cope with searching for a network without any problems.

How to boost your phone signal with your own hands

In most cases, the reason for a weak cellular signal lies in a defect in the antenna, which, in fact, is responsible for this function. Often, owners of inexpensive smartphones from the Middle Kingdom are faced with the fact that the manufacturer has cheated a little by not tightly connecting the antenna to the device’s motherboard. You can correct the mistake yourself, but you need to at least understand a little about how the phone works. Otherwise, contact the service center with a description of the problem.

1. Nowadays, smartphones come in a variety of designs, which is why they are disassembled in different ways; It’s easiest to get to the insides of a phone with a removable cover and battery, but it’s more difficult when the smartphone is non-separable;

Take your time. Before you start disassembling, find a video or text material on the Internet that will show and tell you how to disassemble your specific device and what you should pay attention to.

Please also note: After disassembling the smartphone you lose the warranty.

1. as a rule, the antenna is hidden in the lower or upper part of the case, represented by small copper strips (again, for the location of the antenna specifically in your model, see the relevant materials);
2. after you get to the board, you will find several spring contacts that should fit tightly to the cable located on the back of the structure;
3. if the spring contacts of the motherboard do not fit well to the cable, carefully straighten them using, for example, tweezers;
4. We collect the phone and enjoy a good network signal.

We connect a homemade antenna to the phone to strengthen the signal

The methods discussed above only work if the problem lies with your phone. But, as we noted at the beginning of the material, the cause of a bad signal can be various kinds of obstacles or a significant distance from the station. In this case, you can try to strengthen the antenna of our device with just a piece of wire.

Let us immediately note that this method is not suitable for all phones. The fact is that to implement it you will need a special diagnostic port, which is difficult to get to in a modern non-separable smartphone (in a number of models it cannot be found at all). It looks like a small round connector of golden color.

take a small piece of thin insulated wire;

insert into the connector;

Place it in such a way that it does not interfere with other components or the closing of the lid.

Everything, as practice shows, the phone network signal is greatly enhanced. Isn't it surprising?!

Some users inserted a piece of wire into the 3.5 mm port (under headphones). Sometimes this works too.

Sticker sticker or foil to boost phone signal

In the vastness of foreign online stores, it will not be difficult to find a bunch of different devices for amplifying the signal. Among them, a small sticker sticker is popular, consisting of several metal tracks, which, according to the manufacturer, allow you to get rid of interference.

Similar stripes can be seen in some smartphones by default, so the “magical” properties of the sticker have a right to life.

However, according to a considerable number of users, a piece of ordinary foil will help to achieve a slight improvement in the signal. It is located under the phone cover, closer to the antenna. The method is not complicated, so you can try it.

Strengthening communications using a repeater

In some cases, when the signal cannot be amplified by any of the methods (the walls of the room are too thick, the distance from the base station), they resort to the use of special antennas or repeaters. Such devices are capable of significantly amplifying the signal, but their cost often deters potential buyers.

Where to buy cheap?

You can build something similar with your own hands, but often it does not enhance the signal at all or does it very, very poorly.

For example, some people use the following method:

1. take a metal rod (50 cm is enough), a coaxial cable, a piece of foil (about 10x4 cm) and plywood or plastic;
2. we bend the metal rod so that we get a diamond-shaped structure;
3. glue the foil to the plywood;
4. We connect the metal rhombus and the foil using a coaxial cable (solder);
5. We lift the end on which the diamond is located higher, the other, with foil, is left below;
6. We bring the phone to the foil to check the signal quality.

You will probably need to find the most suitable location for the resulting structure to pick up the signal.

It is clear that such an amplifier is unlikely to provide communications to a large company that is not lucky enough to have an office in an area without network coverage. Here you will have to turn to specialists for help. Today, many companies provide similar services, and will not only offer modern equipment, but will also handle installation.

By the way, you shouldn’t skimp on specialists - for installation, workers use special devices that help determine the most suitable location, select frequencies, etc. An ordinary user, of course, will find it difficult to cope with such a task.

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 expensive phones for the experiment! 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 the long one):

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.

Recently, the coverage area of ​​GSM 900 networks has significantly increased in Russia. However, the situation is far from ideal. If in European countries the problem of unreliable reception is practically absent, then most domestic users often encounter it - in country houses, dachas, etc. And how wonderful it would be to go fishing, hunting, to the countryside, without losing contact with the outside world !

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 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. The sensitivity of 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 the 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” a phone to select a different frequency, but a special function of 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 adjacent 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 are small 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). It is difficult to achieve linear or near-linear performance over 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 a standing wave ratio of 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 automotive whip 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 gives 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 be guided by the signal level in decibels (we remind you 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 is practically no mobile communication.
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 wage increases. 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. DIY 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.

The efficiency of a GSM cell phone antenna is low, reaching 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, which is 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 select the desired GSM antenna device. 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 the desired 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 of suitable dimensions on stands that do not affect the metal part. The screen needs to be grounded. Try placing it on the braid of a 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.

In villages, until now, in most cases there is no dedicated Internet line. It happens that the Internet can be connected via an ADSL line if you have a connected landline phone.

In most cases, all Russian villagers connect to the Internet using 3G modems. And the further the village is, the worse not only the 3G Internet, but also regular cellular communications.

To improve communication quality, the following amplification principles are used:

1. Using an antenna.
2. Using an antenna and amplifiers.
3. Using multiple antennas and multiple amplifiers.

There are ready-made kits, but before you buy them, you need to determine what to strengthen and how. Sometimes one antenna is enough, and sometimes not.

You need to know exactly in what range the 3G signal of the selected telecom operator is transmitted, and where the boundaries of this signal are. To check the signal strength, a regular cell phone or spectrum analyzer will do.

Checking the signal level

Before you can strengthen anything, you need to catch something. We determine the range of operating frequencies for voice communications and the Internet. The image above illustrates the entire range of frequencies involved: television signal, wi-fi, DECT, GSM, LTE, etc. It is important to understand in what range the base station at the point being tested transmits the Internet. It can be transmitted in the UMTS 900 and UMST 2100 standard.

In Russia, the 3G signal has its own standard: UMTS 900 and UMST 2100.

All smartphones and 3G modems work using both of these standards. In cities, due to the small coverage radius, but higher signal transmission speed and stability of operation with a large number of connections, the UMTS 2100 standard is used.

Portable spectrum analyzer SPECTRAN HF-6060 V4, which determines the direction of the antenna

If you are not an installation organization specializing in installing 3G boosters, you can use a phone with 3G support for a one-time connection. We activate the built-in Netmonitor function in it.

How to do this on your phone, look on the Internet. I will give the most common codes.

Phone model	Menu entry code	Note
Apple iPhone	*3001#12345#*, press “call”	2g, 3g, 3gs, 4g, 4gs, 5. For firmware versions from 5.0.1 and higher.
Android	*#0011# or *#*#4636#*#* or *#*#197328640#*#*	The menu should appear automatically after entering the last character, if not try another code
HTC (EVO, Incredible, Touch)	##33284#, press “call”	In the menu, select the network and see the signal level
HTC Wizard 8125, 2125	*#*#364#*#*	The signal level is displayed in conventional values. The higher the value, the higher the signal level
HTC Touch	##33284#	—
Samsung C170, X820	*#9999*0#	—
LG C900	##634#	If it asks for the password 2277634#*# and press ENTER
Nokia 6215i, 6315	##2773	then code 000000

When we enter the engineering menu, various information appears, for example, volume level, battery charging, IMEI, wi-fi, phone usage statistics. I don't recommend changing the values.

If you can't find the settings you need, try another phone. Finally, you need to determine the Rx CH parameter. The first value surrounded by a red frame shows in which range the signal is received. If the value is within 10562-10838, it is UMTS 2100, if within 2937-3088, it is UMTS 900. Having determined the operating range, you can accurately select a 3G signal amplifier, for example, high-quality Picocell 900 or Picocell 2000.

The yellow frame shows the 3G signal reception level. Having constantly changing dynamic parameters of the signal level, we are looking for the point of best reception. Less is better. Ideally, it is better to place the antenna higher on the roof, but you can find points of reliable reception inside the house.

Equipment selection

If you are in a reception area, installing a good antenna with high gain may be sufficient. For example, the antenna AP-1900/2700-17 with a gain of 17 dB, but a narrow radiation pattern. Suitable if there is one base station installed near you and there are no other signal consumers nearby.

Directional antenna AP-1900/2700-17 to strengthen the cellular signal

A fantastic result is shown by the AO-2000-11 antenna - with a high gain = 11 dB and a circular radiation pattern. It works on the set it and forget it principle. Its advantage lies in the principle of operation. It can catch a signal from several base stations at once, which significantly affects the speed of the Internet. No need to look for the direction of the signal.

Omnidirectional antenna, model AO-2000-11 to amplify the 3G signal

In almost 80-95% of cases, when a 3G signal is at least somehow caught, it is enough to screw a 3G amplifier-repeater TAU-2000 from Picocell to the antenna, and you will receive a stable 3G/4G signal.

To prevent signal loss between the antenna and the amplifier, I recommend using a cable with a large cross-section, the ends of which are crimped industrially or with a special tool.

5D/FB PVC cable with N-type connector (male)

Ready-made kits

When you know exactly what type of amplifier you need and whether you need it at all, you can start purchasing equipment. If there are no retail outlets in your city, buy from online stores or directly from the equipment manufacturer.

Kits can be of several types:

• without amplifier;
• with amplifier;

Connection diagram for equipment to boost 3G signal throughout the house

Let's look at kits without amplifiers. Such kits include an antenna and wire. Conveniently, if you have a modem or router, then the cost of strengthening the 3G/4G signal will be minimal. A set of wire and antenna will cost you from 5,000 rubles.

Antennas are selected based on the terrain, number and distance to base stations. This kit can always be expanded with an amplifier; the final price of the equipment will increase, as will the quality of the received signal.

Connection diagram for an antenna kit with a TAU-2000 amplifier and a wi-fi router

You can use any antenna, including those given when selecting equipment, but it is better to buy a modem Huawei E392, although its price starts from 3,200 rubles.

Watch a short video of everything outlined in the article; if anyone is interested in the intricacies, go to the site indicated in the video.

And finally, I will share an observation: buy an antenna and equipment in specialized stores, and not in cellular communication stores; what they sell there does not work.

The Connect antenna is made for the beauty of the interior. The usefulness of this device is questionable. Can only be used as an extension cord for a modem

Ask questions if anything is unclear. Good luck with your shopping.

Articles and Lifehacks

What do most of us imagine when we talk about antennas used in mobile phones?

A pin protruding from the case, which was an indispensable attribute of the bulky devices that the new Russian early users of mobile communications carried with them?

Or does he even have no idea that such a spare part is available in the mobile phone, considering this information superfluous?

But it turns out that there are also some external antennas. Let's figure it out sequentially.

"Standard" antennas

1. For the vast majority of modern phones and smartphones, the norm is internal, or Patch antenna , which is located inside the device body and is not visible even when the back panel is removed (where this is provided at all).

   Advantages:

   • Compact.
   • Reliable.
   • Protruding parts do not cling to clothing when carried in a pocket.
   For each communication standard, the smartphone has its own antenna: GSM, Wi-Fi, GPS or LTE.
2. Short dipole – by now it can safely be considered a thing of history. These are the antennas that were on the first devices.

   In those days, the quality of mobile communication equipment left much to be desired, especially if we were talking not about modern GSM, but about the first generation of cellular networks - AMPS. Moreover, both from the network itself and from user devices.

   Over time, more advanced transceivers appeared, and developers were able to get rid of the protruding pin, completely hiding it in the housing. Currently, models with this type of antenna are no longer available.

3. Telescopic antenna has significantly higher sensitivity in comparison with Patch, however, in terms of dimensions it is even less compact than a shortened dipole.

   Such systems have their own niche - specialized devices for extreme conditions, for example, such as those produced by.

   The benefits are clear: even if you are in some kind of “bear’s corner”, where a normal smartphone is not able to catch the network, a device equipped with a “telescope” will most likely allow the owner to reach where he needs to call.

   We should not forget that such models are often equipped with walkie-talkies, which also require an antenna.

   The disadvantages of “telescopes” are obvious: dimensions and presence of moving parts. But in this situation you have to put up with them, especially since designers usually provide an appropriate margin of safety.

External antennas




Their purpose is obvious: improving communication quality in poor coverage conditions.

However, in the vast majority of cases, such devices are purchased to increase the speed of mobile Internet when using a modem or router.

External antennas can be divided according to several criteria.

According to communication standard:

• CDMA.

By mobility:

• Wearable.
• Automotive.
• Stationary.

By design features:

• Pin.
• Panel.
• Type "wave channel".

By location:

• For enclosed spaces.
• For outdoor use.

Similar devices are used in other systems operating in the GSM standard, for example, in repeaters, wave gateways, and smart home gadgets.

Therefore, if there is a need to purchase such an antenna, you need to clearly understand in what conditions it will be used, and carefully read the descriptions of the models, or even better, clearly formulate your purchase requirements to a consultant.

Connection issues

Just ten years ago, almost every mobile phone had a connector for connecting an external antenna.

However, over time, the quality of communication has improved significantly, and the coverage of mobile operators has covered almost the entire territory where people live, and the need for such connectors has disappeared.

As a result, the developers simply got rid of the “extra part”, retaining only the diagnostic connector, through which you can, in a pinch, connect an external antenna.

It should be borne in mind that in some models a radio module trigger is connected to the diagnostic connector, so using such methods can damage the device, so you should experiment with it only at your own peril and risk.

There is also a “shamanic” method, in which the body of the device is simply wrapped with several turns of wire connected to the coaxial cable of the antenna.

You can’t get high sensitivity this way, but, as they say, a skinny dog ​​can get a tuft of hair.

Finally

Currently, directly connecting external antennas to a mobile phone makes no sense.

If there is a need to ensure signal quality in conditions of poor coverage, for example, in a country house, it is wiser to use a repeater: it will be more expensive, but safer, and the result will be more worthy.

For a snack:

Principles and methods of amplifying 1G, 2G, 3G, 4G, wi-fi signals. Let's say you have a country house where you go in the summer. Having relaxed in nature, you wanted to listen to your favorite music online from your social page, just like you do at home or at work. But you don’t have the usual 3G icon in the upper right corner of the phone. On the YouTube channel “Against the Tide” they explained the technical basics, knowledge of which will help you choose the right additional antenna for your smartphone.

But at the same time you talk on a cell phone, send an SMS message, and receive WhatsApp with a short interval. What is the problem and can it be solved? Before this, you need to understand the communication system. Cellular communications are provided (distributed) using towers. By itself, it can look like anything, even a wooden stick. It doesn't matter! It matters what equipment is on it. We are used to making calls, receiving SMS and using the Internet using a cell phone. In this case, we focus on one signal scale in the corner of the screen. In fact, these are different signals. The description below will be clear to you.

There are many more of these channels. Here are the most common public networks. These signals are issued by special devices (modules) installed on towers. For each - 3G or 2G - separate. The latter is an antenna; it must have a certain design, since the frequency of data transmission depends on it.
The frequency of radio waves is measured in MHz (megahertz). For example:
– 1-2 G communication operates at 890-915 MHz.
– 3G – 1920-1980 MHz.
– 4G – 2300-2340 MHz.
– Television 470 – 850 MHz.
– FM radio – 96 – 108 MHz.
– Wi-Fi – 2400 – 2500 MHz.
These are standard in Russia. Now you are beginning to understand why the TV antenna does not pick up Wi-Fi? To receive or distribute a signal at a certain frequency, you need an appropriate design.
Nowadays, as a rule, in developed cities, taking into account the current needs, 1-4g towers are installed around them. Taking into account the topography of cities, the height of houses, repeaters (repeaters) are installed on the roofs of government or private institutions, where strangers cannot climb, in order to better distribute the signal. The distribution equipment itself or duplication is very expensive, given the fact that the budget in Russia is limited, normal wireless high-speed Internet will not be distributed everywhere. Therefore, there will be no 3-4G Internet on the territory of your dacha due to the lack of appropriate modules on the tower. Well, if the nearest one with the module is less than 50 km away, then there is a chance to catch this signal!

To do this, you need to purchase highly directional antennas that operate at the frequencies you are going to catch. A 3-4G design of this kind looks like this. In appearance it looks like a television one, but the distance between the teeth matters; for Wi-Fi reception it is different.

They need to be clearly directed to the tower. Signal strength is measured in dbi (decibels).

The antenna has its own gain (for example, 20 decibels), but you must remember that you will be pulling a two-core wire from the roof or from a pole to the house. For every meter of wire, the signal is lost by approximately 0.5 decibels. At 20 meters you can lose 10 decibels. A narrow beam with a power of 5 decibels is received at a distance of 3 km by 80%, so an amplifier must be installed at the end of the wire (at home).


If there are no towers with 3-4G within a radius of 50 km, then there will be no high-speed mobile Internet. If funds allow, install satellite Internet, provided that a satellite flies over your area.

If during a telephone conversation there is a gap of several seconds, there is even no GPRS and it is stable. Then no amplifier will help.

The 1G 2G module has a certain number of cells that allow simultaneous two-way communication. If you have the above situation, then most likely there are, for example, 1000 cells, and 10,000 local residents leading the conversation. Remember the New Year when it is impossible to get through by phone.

Check with your mobile operators; on MTS, Megafon or Beeline there is a difference in MHz. Carefully select the antenna according to the desired frequencies. There is no need to connect two amplifiers! The wire from the amplifier can also be connected not to the repeater, but to the USB modem, if it has an input for an antenna. Dbi and dBm in our case, its designations on aliexpress have equivalent meaning. Indicates gain.