How to choose a cellular booster? How and which one to choose a GSM repeater, criteria for selecting the best model

More correct signal amplifier cellular communication called a repeater or repeater, which is essentially the same thing. There are now too many similar devices on the market with different characteristics. The main ones are frequency range, gain and output power. Let's first look at the frequency ranges. The main cellular operators have 5 frequency bands: 800, 900, 1800, 2100 and 2600 MHz.

As we can see from the diagram, 2G, 3G and 4G standards are found in different frequency ranges. For example, 4G operates on 800, 1800 and 2600 MHz. Briefly about the standards: 2G – voice communication only (“voice”), 3G – voice + Internet (cannot be divided, 2 in 1 service), 4G – on this moment(spring 2017) only internet as WiFi. All phones by default always select a higher frequency, that is, if both 3G at 900 and 2100 MHz enter the room, then the phone will always select the upper range, i.e. 2100 MHz. The same thing happens with other standards.

Priority of frequency ranges

The general diagram looks like this:

The essence of selecting the frequency range of an amplifier is to select a priority range from each communication standard that falls inside the room and amplify it.

Which ranges should I choose for the city?

If the goal is to make it as cheap as possible, then you should take a 2100 range amplifier. But sometimes, in order to relieve traffic from the base station, the phone is forced into 2G after the 20th second; this is most often observed with the MTS operator. This is not always critical, because 2G, as a rule, penetrates indoors better. But if financial resources allow, then take a 1800/2100 repeater, thereby strengthening 2G, 3G, and 4G.

If you are in a room where there is basically no connection, for example, a basement, then you can take a 900 or 1800 repeater if you also need 4G high-speed Internet.

If you have a large office with a lot of people, it makes sense to install a 1800/2100/2600 system, because... Mobile operators are going to launch “voice” in 4G in 2017-2018. And when installed system amplification 2G, 3G phones will be automatically transferred to a weak 4G signal coming from the street naturally.

In the city, except for bases, it is absolutely pointless to use the 900 band, because... 2G phones will always choose the 1800 band, and throughput it is 2-3 times higher than that of the 900th. This can be seen from the width of the spectrum in the diagram.

Which ranges to choose for a country house?

If a sign appears indoors next to the reception scale - 3G, H, H+, then you must definitely check with your phone which frequency range it is - 900 or 2100 - and install the appropriate amplifier.

If inside there is always 2G, E or G. Then in 99% of cases you need to install the 900th amplifier, extremely rarely the 1800th amplifier. Again, it’s worth checking with your phone. There is no point in setting up a 900/2100 combination, because if 2100 goes inside, then the phone in 3G will sit at 2100. And if 2100 goes inside, then 1800 goes in too and, accordingly, in 2G the phone will choose exactly 1800 MHz.

The basic rule of the installer is to force the phone into each standard one by one, and see which frequencies fit inside. And select a repeater at a higher frequency for each standard.

How much power amplifier is needed?

Essentially, it is necessary to measure the signal level of the corresponding range at the point of intended installation of the external antenna and make a calculation.

Signal level + antenna gain + repeater gain = repeater output power in dBm (not theoretical, but real for this case). Knowing the power in mW, you can approximately calculate the coverage area.

For example: -70 (input signal from the BS at the antenna installation point) + 11 (antenna gain) + 75 (repeater gain) = +16 dBm.

We look at the table for converting dBm to mW:

In our case, 16 dBm = 40 mW.

Next, multiply this figure by 6 if the frequencies are 800 or 900 and by 5 if they are 1800 or 2100 MHz. 40 * 6 = 240 sq.m. – this is the approximate coverage area in this case for a repeater with Gain = 75 dB in the 900th range.

Important! This is a very approximate calculation of the coverage area, subject to the required number of internal antennas! If the ceilings or walls between rooms are permanent, then it is necessary to install antennas in almost every room! Each antenna has a shorter range than any other Wifi router and is usually 3-6 meters at high frequencies. For comparison, the power of a standard WiFi point is about 80 mW. IN Lately We are often contacted by clients who once had a system installed and antennas placed along the corridor between rooms. You have to either open the ceilings and deliver antennas, or use expensive powerful amplifiers.

Domestic production and quality of amplifiers

Literally 2 words about the domestic production of repeaters - it simply does not exist. Unfortunately no. All amplifiers without any screwdriver assembly are imported from China. And if someone claims to be the manufacturer of this product, you are being deceived.

Regarding cheap models, even if they work, they usually produce noise towards the base station. And when this happens, the SCRF arrives and issues a fine with an order to dismantle the system. Massive problem:

If you decide to install a cellular signal amplifier yourself, we strongly recommend that you obtain detailed advice on setting up the amplifier before purchasing.

In order to correctly select the required power amplifier for cellular communications, you will need:

1. Mobile phone, or a tablet that supports GSM calls on Android OS.
2. Operator SIM card: MTS, Megafon, Beeline, Tele2.
3. Netmonitor program (For iPhone, dial *3001#12345#* to open Field Test)

900/1800 MHz (2G/GSM)

• Open the phone menu:
• In settings: Network-Mobile networks(check the box “only 2G networks”)
• Operator 250 02 (MegaFon)
• Network type EDGE
• LAC: 7604
• CID: 15030

Signal: -85 (dBm) the indicator we need.

To measure a signal in the range 2000 MHz (3G/WCDMA)

• Open the phone menu:
• In settings: Network-Mobile networks (uncheck “only 2G networks”)
• Launch the Netmonitor application
• We see on the phone, for example, the following indicators:
• Operator 250 02 (MegaFon)
• Network type EDGE
• LAC: 7604
• CID: 14730
• RNC: 132

Signal: -96 (dBm) the indicator we need.

To measure a signal in the range 2500 MHz (4G/LTE)

Only for phones supporting LTE connection

• Open the phone menu:
• In settings: Network-Mobile networks (check “4G networks only”)
• Launch the Netmonitor application
• We see on the phone, for example, the following indicators:
• Operator 250 02 (MegaFon)
• Network type EDGE
• LAC: 7604
• CID: 15463
• RNC: 132

Signal: -114 (dBm) the indicator we need.

Select an amplifier (repeater):

To calculate min. coefficient Repeater gain is a simple formula.

Min. coefficient repeater gain = Signal level (dBm) + Coefficient. Antenna Gain (~10 dB)
Example: We received a signal level of -96 dBm, + 10 dB Coefficient. Antenna gains, total 86 dBm = Min. Coef. Repeater Gain.

To calculate the output power, it is necessary to calculate the coverage area and take a margin of about 10-20%.
Internal antennas are selected from the consumption of 1 piece. per 100 m² in the absence of walls. If there are walls made of plasterboard, internal antennas are taken for 40-60 m², for brick - 20-40 m², for concrete - the antenna is taken separately for the room.

How to measure signal level with using iPhone

Determining 3G signal strength using an iPhone

How to choose a gsm repeater and not overpay?

Anyone who is faced with the problem of the GSM signal disappearing, “gurgling” when talking on a mobile phone, comes to the decision that they need to somehow correct the situation. Nowadays, it has become a good tradition to open Google or Yandex, ask a question and select suggestions on your question. And here the most difficult part begins - a million offers, each seller tries to impose his very, very, best equipment.

This statistical data is taken for Ukraine as a whole. If we consider in particular by city:

GSM-1800 - used in cities with a population of more than 50 thousand people (regional centers, district centers);

GSM-900 - used mainly along highways, in rural and mountainous areas, as well as in forests.

What caused this distribution?

Standard mobile communications GSM-900 has a wide coverage radius (up to 35 km from the operator’s base station), the signal is better reflected from buildings and terrain. Accordingly, it is used to organize a signal over large areas with just one base station.

The GSM-1800 cellular communication standard is used to increase the number of subscribers served. In comparison with GSM900, it allows you to serve two or more subscribers from one operator base station. But one of the downsides is working in a small area.

Three pillars that you need to rely on when choosing a gsm amplifier.

a) Mobile communication standard.

b) Mobile signal gain.

This parameter plays a big role in the operation of the repeater. Gain is the ability of a repeater to receive a signal, isolate the useful signal from noise and amplify it to the required level. The higher the value this parameter, all the better. When the signal level from the operator is weak (absent or 1-2 divisions on the mobile phone at the location where the receiving antenna is installed), then you need to select a more powerful repeater - at least 75-85 dB. If in the places where the receiving antenna is installed the signal level is 3-5 divisions, you can select amplifiers with a gain of 55-65 dB.

c) Repeater output power.

The power of the repeater is directly related to the coverage area of ​​the gsm signal. For example, if you need to boost the GSM signal in a room up to 70 sq.m., then models with a power of 5 mW are suitable. In premises with an area of ​​150 sq.m. at least 10 mW will be required. Accordingly, for an area of ​​400, 700 squares already need 100 mW (20 dBm) and 300 mW (27 dBm).

How to determine the number of GSM antennas that need to be installed?

Mobile repeaters, which are used by subscribers to strengthen a weak signal, are low-power transceivers. Accordingly, in order to strengthen the GSM signal throughout the room, it is necessary to select the required number of service GSM antennas, as well as place them correctly.

An example of the shielding properties of premises:

These shielding properties also apply to the placement of the receiving (external) antenna. During installation, it should be as far apart as possible from the service (internal) antenna. If the separation of these antennas is insufficient, the gsm amplifier will self-excite, i.e. the amplified signal from the service (internal) antenna will fall on the receiving (external) antenna, thus the useful signal from the telecom operator will not be able to amplify.

Internal GSM antennas, as a rule, are installed in rooms where it is necessary to provide a stable and high-quality signal. One GSM antenna covers an area of ​​70 to 150 square meters, provided that it is one whole room, or several with a common open corridor, or with plasterboard/glass partitions. An important role in the coverage area is played by the power of the GSM repeater, which is an integral part of the entire mobile communications amplification system.

Conventional scale for matching signal levels in dB and divisions on mobile phones.

For your convenience, all necessary actions are discussed with an example and described below.

So, what we are given: a room of 25 m2, cellular signal low (one division) or completely absent.

First Step: Find Out Your Current Cellular Signal Strength

The signal level must be measured at the location where the external antenna (receiving the cell tower signal) will be installed.

In our example we used samsung phone C170 with MTS SIM card.
By dialing the code corresponding to this phone, we find ourselves in the engineering menu.

After we entered engineering menu, we select the desired screen (see picture below) by pressing the up/down arrows.

The column on the left is the channel numbers.

It will help you determine the range of the repeater:
- channels from 1 to 124 correspond to the GSM 900 range;
- channels from 512 to 886 - GSM 1800;
- channels from 974 to 1024 - E-GSM range (only Picocell repeaters can operate in this range).

The picture above shows that in our case, all channels of the MTS operator operate in the GSM 900 range.
This means that we also need a repeater operating in the 900 band.

The column on the right is the signal reception quality.

The lower the value, the better the signal (50 and below is the most high quality signal, 105 and above is the worst).
The picture above shows that the signal quality of all channels leaves much to be desired.
The best indicator - 082 dB - is for channel No. 035.

Now we know the range and signal quality of the selected operator.
To find out the range and quality values ​​for another operator, you need to take measurements by installing the appropriate SIM card on your phone.

Second step: find out the signal gain

To do this, you need to find out what size area reinforcement is needed.
Knowing the area, you can calculate the coefficient you need.
To calculate, use the table below:

In our example we are talking about a room with an area of ​​25 m2.
From the table it follows that to obtain a high-quality signal in the GSM 900 range over an area of ​​25 m 2, a gain of 8 dB is needed.

Now we know:
- the value of the signal quality of the selected operator (in our example it is 82 dB);
- the range in which your operator(s) operate (in our example, this is GSM 900);
- gain required for high-quality signal amplification (in our example - 8 dB).

Third step: choose the right equipment

To do this, you will need to substitute the above values ​​into the following equation:

It follows from the equation that the gain you need must be less than or equal to the gain of all the equipment involved.

To find out which equipment will suit you, look at the gain values ​​specified in the specification of that equipment and simply plug them into the equation.

You will find information about the gains of repeaters and antennas by going to the page of the desired model in the catalog of our website.

Cable signal loss values ​​are listed in this table according to different ranges:

Now let's find out what equipment is suitable for the room from our example:

We have already established that we need to achieve a gain of 8 dBm or more, and the signal quality is 82 dB.

1. Select an external antenna. For example, .

In the "Characteristics" section we find the gain values ​​for this antenna - 7-9 dB.
To be sure, we choose the smallest value - 7 dB.

2. Select an internal antenna. For example, .

Again we find the gain values ​​in the “Characteristics” section.
We also choose a smaller value - 7 dB.

3. Select a repeater. For example, .

We find its gain value. It amounts to 50 dB.

4. Calculate the signal loss in the cable.

To do this, we need to know what kind of cable we will use and how many meters of this cable we will need.
In our example, we need 10 meters of cable. We will take the 8D-FB cable because it is of the highest quality and the losses when using it are minimal.
Thus, in our case the losses will be 1.3 dB(We multiplied 10 meters by 0.13 dB - the loss value corresponding to the cable we selected in the GSM 900 MHz range).

5. We substitute the obtained values ​​into the equation and find out whether the selected equipment in our case will be able to amplify the signal or not.

8 ≤ 7 + 7 + 50 – 1,3 – 82

8 ≤ – 19,3

We see that the gain of the equipment we have chosen is not enough to provide high-quality communication over the entire area of ​​our premises.

This means that we need to choose more powerful elements of the amplification system (external and internal antennas, repeater).

1. External antenna. This time we'll take the AL-900-14 antenna.

Its gain is 14 dB.

2. Internal antenna. Let's choose Antenna RAO-11GL-60.

Gain – 11 dB.

3. Repeater. Let's take the same one.

Gain - 60 dB.

4. Cable. We'll leave it the same.

This means that the losses, as before, will be - 1.3 dB.

5. Re-substitute the values ​​into the equation:

8 ≤ 14 + 11 + 60 – 1,3 – 82

8 ≤ 1,7

Better than last time. But we are still not satisfied with the resulting value.

Since the required value is quite a bit short, we will simply add one more of the same internal antenna.

To add another antenna, we need a signal divider.

This is important to consider, since the divider, just like the cable, has a certain amount of loss that must be taken into account.

You will also find the value of losses in the divisor in the “Characteristics” of the product.

We will take PicoCoupler 800-2500 MHz ½.

It divides the signal into two equal parts. And the losses amount to no more 3.4 dB.

Now let's re-calculate our equation by adding the gain values additional antenna and divider losses.

8 ≤ 14 + (11 + 11) + 60 – 3,4 – 1,3 – 82

8 ≤ 9,3

The value obtained this time is perfect.

This means that high-quality cellular communication throughout the entire area of ​​our premises is guaranteed.

Important

As an example, we deliberately chose a rather simple case. But in practice, we have to solve more complex problems and take into account a lot of nuances: the output power of the equipment; the number of rooms in which the signal needs to be amplified; the material from which walls and barriers in the signal path are made; signal quality indicators of several operators (in our example we took one - MTS); distance to the nearest cellular operator base station, etc.

The steps described in this article will certainly help you determine the equipment you need quite accurately.

But to ensure that you receive maximum signal amplification at the best price, we recommend that you consult with specialists.

It is difficult to imagine a modern person without a mobile phone. A progressive person always strives to remain within the zone of access to his circle of interests, and a modern mobile phone with Internet access is his main tool. The mobile phone provides all working and social contacts, stores information about important matters and allows you to access the World Wide Web at any time... But what to do if circumstances take you out of the access zone mobile network, taking you away from civilization? One of the most effective solutions will be to select and install a device such as a GSM repeater or a 3G network repeater.

Choosing a repeater

So, how to choose the right cell phone booster? First of all, you should measure the signal and find out which bands the telecom operators you need use (for their subsequent amplification). Please note that different frequencies are used for voice and data communications.

You can measure the signal cell phones(iPhone, Samsung Galaxy) by logging into service menu. It is necessary to measure the signal at the location where the external antenna is intended to be installed.

Using the table below you can figure out what power you will need for a repeater. If the signal level is higher, then the amplification area will be larger and, accordingly, vice versa. The table shows the most popular Russian repeaters from Picocell. Other companies have similar ones.

The worse the signal in the place where the receiving antenna is supposed to be installed, the greater the distance from the place where the antenna is installed to the repeater itself (cable in the system), the larger the area of ​​the room or street area, the more powerful the repeater will be required. At the same time, we draw your attention to the fact that a more powerful repeater will be required not only if the room area is large, but also if each of these parameters deteriorates.

When choosing, it is worth considering many factors: the required network coverage area, the type and complexity of the room in which the amplifier is supposed to be installed - whether it is closed or open. In addition, it will be important whether there are partitions and interfloor ceilings in the room, and what material they are made of - they can impede the passage of the signal. The price of an amplifier in most cases depends on the power, as well as the number of supported bands.

What if you need both a GSM repeater and a 3G repeater?

If you need to strengthen several operators using different frequencies at once, or in addition to conversation you also need reliable access to the Internet, you need a multi-band repeater that supports the required frequencies. Another option is two or more repeaters that amplify the desired frequencies. When installing a repeater outdoors, a repeater in a special housing is required.

It should also be remembered that the quality of operation of devices such as a GSM amplifier or a 3G signal amplifier is significantly influenced by the correct location of the antennas of the amplification system relative to themselves and relative to the main receiving antenna. It is necessary to avoid looping the repeater signal when the amplifier begins to receive and retransmit its own signal instead of the operator's signal. To do this, it is necessary to install the antennas at a distance of at least 10 meters from each other.

For a non-specialist in radio engineering, the process of choosing a GSM or 3G repeater may seem very complicated due to the abundance of technical subtleties. But our professionals are always ready to help you in any situation, take all the required measurements and select the device you need.