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Devices / 11/14/2017

Do-it-yourself external antenna for 4g lte modem

Never a Russian person, given the opportunity to save money, will not refuse this. If in the country or outside the city, in an apartment or a cottage, the Internet speed is low, why buy additional devices? We will tell you how to make the simplest and cheapest external antenna for a 4g lte modem with your own hands.

Characteristics of external amplifiers for the modem

Antennas are devices for signal amplification. They are of different types:

• narrowly focused;
• sector;
• omnidirectional.

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

Sector is capable of limiting radiation in a specific sector. For example, if you put a sheet of iron behind the omnidirectional antenna, you get a sector antenna with a sector of 180 *. Such a sheet of iron is called a screen.

The most effective is a directional antenna, which is a special case of a sector antenna. Due to the selection (of course, an accurate calculation in fact) of the curvature of the screen, you can get a narrowly directed beam of radio wave radiation.

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

Simple external 4g antenna with your own hands

A typical collecting focusing external amplifier for a modem is sold in the store and costs money.

If you have a case from an old PC (and they are usually spared to be thrown away and taken to the country - suddenly come in handy), then you can make an external directional 4g antenna with your own hands. You will need the whole body, the scissors for the hardware, and you will have to buy a USB cable for the external amplifier.

We will not describe the steps, they can be seen from the drawing.

And here's the result.

You can simplify the design.

If there is no piece of metal, take thick cardboard and cover it with foil.

If you are too lazy to paste over, look in the kitchen among the dishes. You can make just such an antenna for a 4g modem with your own hands.

Thanks to the user Ukshuinik, who was not too lazy.

DIY 4g panel antenna

To make an external homemade antenna for a 4g lte modem with your own hands, you will need:

• Galvanized iron sheet for 334mm * 290mm panel and for four patches, each of which is 118mm * 70.5mm.
• A coil of copper wire with a diameter of 2 mm.
• A piece of copper foil for cutting a patch with a diameter of 21 mm.
• Styrofoam under patches.
• Adhesive for gluing patches to foam.

All dimensions of the external device are shown in the drawing.

Make a full-size drawing of the external amplifier on paper, lay out the patches. Then bend the wire and solder it to the patches. Drill a hole for the cable plug in the base and solder the plug. Then cut the circles out of the foam, glue them to the base where the patches are. Glue the structure on top.

To use such an external antenna to amplify a 3g / 4g signal with your own hands, the modem must have a cable connector.

Antenna Kharchenko for 4g modem do it yourself

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

All parameters are calculated depending on the transmission and reception frequency of the modem.

You will need copper wire, a sheet of aluminum with a thickness of 2 mm. First, you need to bend the wire so that the sides do not touch in the middle. And solder the ends.

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

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

Distance 3.6 cm.

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

All mobile operators that offer Internet access via the 3G network (MTS, Megafon, Beeline, etc.) have a certain coverage area. If you are behind it, the Internet connection will be very weak, the connection will be unstable, the speed will be slow. In such cases, you can use options that will enhance the signal of the 3g modem.

How to Amplify 3G Modem Signal Using Speakers

The first option, how to amplify the signal of a 3g modem with your own hands, which you can try at home without unnecessary waste and effort, is to use ordinary sound speakers. Mobile Internet users noted that if you move them closer to the modem, the signal level increases by 10-20%. This is not a lot, but if the connection quality is poor, it gives a tangible increase. To get rid of annoying clicks from the speakers, the sound should be set to a minimum.

Signal amplifier for 3g copper wire modem

Another way, how to easily amplify the signal of a 3g modem with your own hands, will require you a little more action than the option with speakers. You need to make a structure of wire and a tin can, which would act as an antenna. The algorithm of actions is as follows:

Take copper wire (preferably a long piece).

1. Open the gadget and make 5-6 turns around the SIM card.
2. Pull the other end to the window.
3. Take a tin can or cut off the neck to make a "glass". He will act as a reflector that enhances communication.
4. Tie the free end of the wire to the bottom of the can.
5. Rotate the neck towards the nearest operator's tower. The increase in the quality of the Internet will be up to 90-95%.

How to strengthen the signal of a 3G modem with network settings

Before tinkering with antennas with your own hands, you should try another method, how to enhance the reception of the 3g modem signal. Some mobile Internet users do not know that by default, when the quality of the connection is low, the device automatically switches to the 2g communication mode, with which it is impossible to work normally. In this case, the transition occurs even in the presence of 2-3 "sticks". To avoid such situations, it should be clearly indicated through the device settings that only a 3g connection should be used. To change an option:

run the network setup program;

1. select the "Connection" tab (or with a similar name);
2. further, the network search mode must be changed from automatic to 3g.

This will force the device to only operate on those frequencies, without dropping the connection to a slower speed. Some modems do not have such an item in the application interface for the device. In this case, you should look for a combination to activate the built-in command in the instructions for the device or in specialized forums. Each modem model has its own order of enabling the option.

Strengthening the signal of a 3G modem with a USB extension cable

This is not the best, but a working way to easily amplify the signal of a 3g modem with your own hands. Suitable for people who do not want to disassemble, re-solder their device. The design works on the principle of a satellite dish. To make it, you need to buy a "reflector" (jar, bowl, CD), USB cable "mom-dad" 3 meters. The creation process is as follows:

In the middle of the disk, make a mount for a USB flash drive, or tape it with tape.

1. Connect the cable with one end to the computer and the other to the modem.
2. You can use a stick instead of the holder, or simply attach the disc from the street side to the front of the house.
3. Point the flash drive in the direction where the signal is strongest.

The increase in connection quality is not very large, because the USB cable loses some of it due to the length, but it still improves the connection. The mirror surface of the CD acts as an amplifier. It is recommended to use a bowl instead of a disc because its reflective surface is larger and the reception will be even better. Enamelled options are not suitable, use stainless steel products.

Dedicated external signal booster for 3g modem

Operators are aware of communication problems, so they are constantly trying to expand the coverage area. As an intermediate solution, for example, a 3g signal amplifier was created for the Megafon modem and other companies. This is an antenna that operates at the required frequencies, and you need to connect it directly to the device. When choosing a model, you should rely on the indicators of the radiation pattern and gain.

For effective operation of the antenna, it must be directed towards the tower of the mobile operator, which is closest to your home. Attach the stand so that the pins are perpendicular to the ground. Note that the longer the cable length, the greater the signal loss along its length. A short cord will provide sufficient connection gain, provided it is of good quality. If you bought an amplifier, then you should not save on the cable.

How to amplify a 3G signal with your own hands using a repeater

The most effective is amplification using a special device - a 3G repeater. Amplification is possible only if the phone picks up at least a minimal 3G signal. This approach can be called fully professional, since after installing the repeater you will receive:

maximum possible amplification of the 3G signal;

• the maximum speed of the mobile Internet that a mobile operator is capable of providing;
• stable reception area within the coverage radius of the internal antenna;
• getting rid of problems arising from a weak signal: disconnections, subscriber inaccessibility, interruptions during a call, and others.

Andrey Baryshev, Vyborg

A large number of wireless Internet users have to deal with the problem of low connection speeds. This problem is especially relevant for subscribers living outside of large settlements and at a great distance from the nearest towers of cellular operators. But even in densely built-up cities, it can happen that reception of a direct cellular signal is impossible, you have to be content with the use of the reflected signal, weakened several times. In all these cases, it can be quite effective to use additional remote antennas, the proposed designs of which differ in the principle of their construction, complexity and declared radio technical parameters.

In my case, the problem was the extremely low speed of the Internet connection due to the great distance from the tower (10 km in a straight line). In addition, reception of a direct signal was impossible due to the panel five-story buildings in front. For this reason, the 3G signal was practically not detected by the modem, and it was possible to work only in the GPRS mode (the MTS MF192 + modem was used).

Numerous ways to improve the received signal were considered, including those found on sites on the Internet. After analyzing various antenna designs and feedback on their work, it was possible to conclude that either options for directional antennas of the "wave channel" type, or dish-reflectors, in the focus of which the modem itself is located, work most effectively. But the manufacture of such antennas requires precise and complex calculations and rather specific materials, so making them at home is not easy. And the options with the removal of the modem itself "on the street" (outside the window, on the roof, etc.) immediately disappeared due to the need to use a USB extension cable with a length of more than 15 m. Even with a much smaller size of such an extension cable, the modem may stop working normally due to attenuation signal and supply voltage drop. In addition, the modem, in principle, is not designed to work in outdoor conditions with significant temperature and humidity changes. Therefore, only indoor directional antennas were considered, the best of which, according to numerous reviews, were the Kharchenko zigzag or bi-square antennas.

But, despite the external simplicity, you can also find a lot of manufacturing options for such an antenna, while completely different sizes of the constituent elements and methods of layout of the entire structure are often indicated. To compare all the options, in practice, several such antennas with different sizes and in different "modifications" were manufactured and tested in operation, including antenna options with four and six squares (double and triple bi-square, respectively). At the same time, my designs made it possible to quickly change the configuration and dimensions of various constituent elements.

It should be said that in my case, the use of double and triple bi-square options did not show practically any advantage over the usual, simple version of this antenna. Therefore, in the future, a detailed calculation and manufacturing features of a "classical" antenna will be considered.

Antenna calculation

To accurately calculate the size of the antenna, you do not need any special theoretical knowledge or any programs.

The perimeter of the antenna frame of this type should be equal to the wavelength of the received radio signal. In our case, the wavelength can be calculated knowing the frequency of the 3G signal, which is 2100 MHz. To do this, you need to divide the speed of propagation of radio waves (300,000 km / s) by the frequency, as a result of which the length of the frame is equal to

300,000 / 2,100,000 = 0.143 m.

Since the frame is in the shape of a square, you must divide its total length by 4, resulting in the length of each side of the square, equal to 35.75 mm. In many sources, you can find completely different side sizes - from 27 to 53 mm. Obviously, such antennas are already designed for a different range, for example, GSM or Wi-Fi, whose operating frequencies, respectively, are lower or higher than in our case.

The gain of this antenna is approximately 6 dB. When manufacturing it, all dimensions must be observed as accurately as possible; the quality of work greatly depends on the quality of manufacture. It should be noted that any antenna without an amplifier does not amplify the signal as such, but distinguishes it against the background of other signals and various interference (if the antenna is not broadband). Due to this, we get the signal we need, the level of which is much higher than the noise level. Therefore, accurate adherence to the antenna dimensions is important, because in this way we will get an accurate tuning to the desired operating frequency!

A reflector can be used to increase the gain up to 9 dB. It can be a metal plate, fine mesh or even foil glued to plywood or thick cardboard, with dimensions 10-15% larger than the area of ​​the antenna itself. In this case, the reflector will be 125 × 75 mm.

Manufacturing

Thus, an antenna for receiving 3G signals (without a reflector) will look as shown in Figure 1.

Picture 1.

For its manufacture, we need a copper wire with a cross section of at least 4 mm 2 (you can use, for example, a "core" from a VVG or NUM power cable). The perimeter of each square is equal to the wavelength - 143 mm. Since the antenna consists of two squares, you will need a piece of wire 2 × 143 mm = 286 mm long.

We divide the wire into 8 equal segments and bend in these places at an angle of 90 °, and solder the free ends together to form a closed loop (Figures 2 and 3):

The reflector should be fixed behind the antenna “squares”, and the distance to the reflector is also of great importance, since it affects the input impedance and matching with the connecting cable. Theoretically, this distance should be ¼ of the wavelength, which in our case is 143/4 = 35.75 mm. But my antenna, for example, performs better at a distance of 18 mm, which is 1/8 of a wavelength. Therefore, it is better to make the distance to the reflector adjustable and experiment with it during the tuning process. To do this, we take a piece of copper tube of a suitable diameter (our connecting cable should go there), for example, from a telescopic antenna for receivers / TVs. Give it the shape shown in Figure 4.

In the reflector plate we drill a hole in the center so that this tube fits snugly there. It should not dangle freely, then it is possible not to solder it to the reflector and, when tuning, move it by adjusting the distance to the antenna plane. Solder our two-square frame to this tube, as shown in Figure 5).

We pass the cable through the tube and solder its central core to the inner corner of the frame opposite the tube hole, and the braid-shield of the cable to the tube on the opposite side of the reflector (Figures 6 and 7).

After the final tuning of the antenna, the tube can be soldered to the reflector. The plane of the antenna must be strictly parallel to the plane of the reflector, because even a slight skew and non-parallelism can greatly reduce the signal level. To ensure the rigidity of the structure, between the reflector and the extreme corners of the frame, you can glue PCB or other good insulator pads.

Modem connection

If your modem does not have a special connector for connecting an external antenna, then you will have to make a kind of adapter that is put on outside and transmits a signal to the built-in antenna of the modem by means of re-radiation. In the simplest case, you can simply wrap the modem tightly (at the location of its internal antenna) with several turns of the central core of the connecting cable, as shown in Figure 8.

The number of turns, usually equal to 2 ... 5, is selected when tuning to the maximum of the received signal. Then these turns should be fixed to the modem with electrical tape. And you can make the design more complex, more convenient and efficient. This version of the adapter is shown in Figure 9.

Structurally, it is a ring that tightly fits the body of the modem at the location of its internal antenna. The ring can be made from a 45 mm wide strip of copper foil, the ends of which must be soldered together. The central core of the HF connecting cable is soldered to this ring. From another strip of the same foil, but with dimensions of 25 × 75 mm, a half-ring is bent, as shown in Figure 9, and the braid-shield of the cable is soldered to it. There should be no electrical contact between the ring and the half ring. By adjusting the position of the half-ring and the angle of its inclination relative to the modem, you need to achieve the maximum level of the received signal. The dimensions of such an adapter were not calculated theoretically in any way, but were selected through experiments. For modems of different types and models, the location of the built-in antenna inside the case can also be different (in the area of ​​the USB connector or at the other end of it). This should be taken into account when placing the adapter on the case of your modem!

HF interconnect cable

A little about the types and brands of cable. In addition to quality indicators, the cable can have a different wave impedance - 50 or 75 Ohm, which must be taken into account when choosing it. The resistance of wireless modems is typically 75 ohms. Therefore, it is of course better to use a 75-ohm cable. Judging by the numerous recommendations, it is better to use cables of brands 10D-FB, 8D-FB, 5D-FB (in decreasing order of quality) due to the low signal attenuation rates. RG-6, RG-8X cables show themselves worse. Therefore, especially with a cable length of more than 5 m, choose a better option, otherwise you can lose all the “gain” that you get from the antenna!

Antenna tuning

With the antenna positioned so that it is directed towards the nearest cell tower (preferably near or opposite a window), adjust the position of the antenna and the distance between it and the reflector plate by moving the tube. You need to be guided by the signal level, and for this it is better to use special programs, for example, the “MDMA” program (can be downloaded on the Internet), where there is a signal level scale in decibels. This program does not work with all modems, but there are others like it that show the signal level in decibels (signal-to-noise ratio). You can also navigate in the standard connection program for your modem by the signal level of the antenna icon, but this is not very convenient, because there, firstly, there is a somewhat delayed reaction to a signal change (up to 10 - 20 s), and then second, it will not be entirely correct. Because it is the signal-to-noise ratio that is important, and not the signal level as a whole.

In my case, the antenna scale indicator of the "native" connection manager increased after connecting and tuning the antenna slightly, by only 2 - 3 divisions. However, the speed of the Internet connection increased very noticeably. The download speed has increased from 0.5 Mb / s to 3 ... 4 Mb / s in the daytime, and even more at night. Without such an antenna, as mentioned earlier, reception of a 3G signal was generally impossible.

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One of the most important factors affecting the speed of 3G WCDMA UMTS HSDPA HSUPA Internet is the signal strength. The quality of the received signal can be improved by using external antennas for 3G / 4G modems. In this article, I will describe the most successful options for improving a 3g signal in terms of price-quality ratio.

Do not mindlessly buy the most expensive or cheapest antenna to amplify a 3g signal. First, we need to find out the level of the input signal with which your 3g modem "sees" the operator (often referred to as RSSI). And we need to know it not in percentage / sticks / other parrots, but in dBm - decibel relative to a milliwatt (in more detail about what dB, dBd, dBi, dBm, Watts are and why you need all this - you can find out in the next article :).

IMPORTANT, all the following manipulations must be done with the Internet disconnected! Just connect the 3g modem to your computer, but do not press the "connect" button.

You need to look for the signal level in dBm in the settings of the 3g modem, while, in advance, in the settings of the 3g modem, you need to set the forced network selection - "only 3G" and no "priority 3g"! For example, in a 3g modem from Beeline, this is done like this:

If in the settings of your modem there is nowhere to see the signal level in dBm, then you can use simple and convenient programs (how to determine the signal level of 3G and an overview of the program for 3g Huawei modems can be found in the following article :.).

In a 3G modem, the input signal level will be indicated with a minus sign « - » and the closer the figure is to zero, the better the 3g modem sees the BS, which means, possibly, the speed will be higher. For example, the value -46 dBm this is a "great signal", better than -54 dBm but worse than -42 dBm.

Actually, the signal to -75 dBm- great

-75 -85 dBm- medium, will provide a stable connection and an acceptable speed

-95 -101 dBm- bad signal, which will not allow you to work normally, you cannot do without a powerful directional antenna.

When the signal is not stable, the measurements will float. For example, if you “catch” a reflected signal, then the reading can vary from -75 dBm to -101 dBm, and when you “catch” a direct signal, -75 dBm -79 dBm.

It is advisable to measure the input signal level at the intended place of the antenna installation, but do not forget that the higher the antenna installation point is, the better the received signal. If you have a private house, the difference between the signal received in the room and the signal received at a height of 5 meters above the level of the roof of the house is on average 30-40 dBm. But this is not an axiom, the difference can be either more or less, this is influenced by multiple factors: from the materials from which the building is made, and ending with the landscape and terrain.

Therefore, it is worth being Carlson and still fly to the roof, or climb a tree near the place where the external antenna is supposed to be installed (do not attach antennas to trees, they tend to get wet and turn into a source of interference, do not force the tree to take revenge on you!) ...

If the signal strength that you measured while sitting on a rooftop or in a tree is within:

up to -85dBm, then, most likely, it will be enough for you to use an antenna with a small gain. For example, the finished “ set # 1 for 3gUSB modem"Or an antenna made of quality materials" PA 3G - 13», Which can be completed with the required cable and adapter. Or a cheaper analogue "PA 3G - 13" in the form of a ready-made " set # 3 for 3g USB modem", And you can also just bring the modem out, using, here ATTENTION, QualityUSB extension cable, made specifically for the 3g modem. Such a USB cable, unlike a coaxial cable (which goes from the antenna to the adapter), does not attenuate the signal, for which it deserves a separate article:

from -85dBm down to -95dBm, then, most likely, you will need a more powerful antenna, for this they are well suited: ready " set # 4 for 3g USB modem", Or an antenna made of quality materials" PA 3G - 16", And if you lay our USB extension cable, then enough and “ PA 3G - 13».

from -96dBm down to -101dBm, then you will have to "pull out" the signal using the ready " set # 5 for 3g USB modem", Or almost any satellite parabola with a special feed "OP - 3G"... And if you lay it, it's still the same USB extension cable straight to the antenna, that's enough and "PA 3G - 16" or "AX-2017Y".

below -101dBm- this is an individual case, most likely a set of measures will be needed, consisting of a powerful antenna and USB extension cable laid to it, as well as, it is advisable to use a USB 3G modem with an output for an external antenna, or redo your 3g modem, as explained in the following article:. The following are suitable as powerful antennas: AX-2020P, OP - 3G.

Here the task of an external antenna for a 3g modem becomes clear: its mission is to “receive” a signal where its level is high and, using a feeder (in our case, a coaxial cable), “send” it to you in a 3g modem.

After wandering around the vastness of the world wide web, you can find a huge number of ready-made solutions, at prices ranging from several hundred rubles to impressive amounts of several tens of thousands of rubles, as well as options for making homemade devices. Let's try to figure them out. The most important tactical and technical characteristic of an antenna is its gain. As a rule, the antenna gain is measured in decibels dBd or in dBi, without going deep into theory, I will tell you about the most interesting. Let me just say that the difference between dBd and dBi is 2.15. That is, the same antenna can have a gain of 14 dBd and 16.15 dBi. Let's fix:

You choose an antenna from the catalog -

Antenna "A" has a gain = 15 dBi

Antenna "B" has a gain = 14 dBd

Which antenna has the highest gain?

Many people think that antenna "A" is better, but we all know that if we bring the values ​​of the gain to one unit of measurement, we get:

"A" - 12.85 dBd

"B" - 14 dBd

An equally important characteristic of the antenna is its SWR. Further, I quote Wikipedia: “It characterizes the degree of matching of the antenna and the feeder (they also talk about the matching of the output of the transmitter and the feeder) and is frequency dependent size ”- and it doesn't matter that the majority of people did not understand anything. There is one important word here - “ frequency dependent". All high-quality antennas have good VSWR at a certain frequency, let's simply call it the operating frequency. And the higher the operating frequency of the antenna, the higher the requirements for the accuracy of its manufacture and tuning. And a couple more quotes from Wikipedia: "In the ideal case, VSWR = 1, this means that there is no reflected wave", "Usually acceptable values ​​of the coefficient are in the range from 1.1 to 2.0."

Most often, 3G operates in the 1900-2200 MHz range, these are super high frequencies. Therefore, it is practically impossible to independently make a high-quality antenna without special equipment, in the form of a panoramic SWR meter (such a device costs up to several hundred thousand rubles). A homemade 3g antenna, in 99% of cases, will have a SWR at an operating frequency, most likely several times higher than that of a factory antenna, and in some cases even go off scale. The gain of such an antenna will come to naught. But, to declare that there will never be any effect from the use of such an antenna would be slyness. As mentioned above, the difference between how the 3G modem sees the signal inside the room and how the 3G modem sees the signal on the roof is often quite large. Therefore, in spite of the low gain of the handicraft antenna or its absence, it is possible to improve the received signal (if you still want to tweak after reading, we have prepared for you our own variation on the topic: “ Antenna for 3g modem do it yourself"). About those cases when someone says: “I put a TV antenna on my 3g modem, and now everything is flying with me,” I will say the following: “And this happens. Each antenna is a piece of metal, which, when connected to a modem and lifted up, will give a positive or negative effect, but if such craftsmen simply installed their 3g modem, in the same place as the TV antenna, using a USB extension cable, then it would be useless it would definitely be more. " Therefore - give the TV antenna to the one who needs it!

The antennas of our Chinese neighbors, as well as making an antenna on our own, is a game of roulette. There are quite decent copies, but more often it happens like this: http://www.lan23.ru/forum/showthread.php?t=7397

The use of antennas that are not tuned to the operating frequency of the 3g modem creates poor conditions for its operation, while most modems switch to increased operating power, but most of the radiated energy will return back to the modem. It happens that this leads to overheating of the modem, and in rare cases to its failure. But it's cheap!

If you have already decided on the necessary, in your case, antenna gain, then you should find out the following.

A little about the types of external antennas. Antennas are directional and circular. The most common directional 3G antennas are: 1) Wave channel (Yagi antenna); 2) Panel antenna; 3) Parabola paired with an irradiator. Let's take a closer look:

1) Wave channel (Yagi antenna)

The photo shows the antenna "AX-2017Y"- 24-element wave channel with a gain of 17 dBi and a length of 1 meter (note that the antenna gain is directly related to its overall dimensions and this is an axiom). The advantages of the Yagi type antenna include a good gain (hereinafter referred to as KU), and low cost. By cons - its high windage and narrow bandwidth or operating frequency 1925-2200 MHz. This antenna will work well in the 3g range, but in the 2g range as a simple piece of hardware. And also, birds like to sit on such antennas.

2) Panel antenna

The photo shows the antenna "PA 3G - 16" - microstrip panel antenna with a minimum gain of 16 dBi.

Pros: less windage; the emitting elements are protected from atmospheric precipitation; the choice of polarization, a wide range of operating frequencies 1700-2200 MHz, which allows it to be used both in 3G and 2G networks; appearance (the owners of the cottages will understand me). The only disadvantage is the price.

3) Omni-directional antenna

An antenna of this type is standardly installed, for example, on wi-fi routers.

popularly, they are called "pipettes"

Antennas of this type radiate a signal in all directions, they have a weak gain in comparison with directional antennas. An antenna approximately 8 cm long will have a gain of about 2.15 dBi. They make antennas, where the KU reaches 9 dBi, its length will already be more than 75 centimeters. More powerful 3g antennas with circular directivity, it makes no sense to do, because their radiation pattern becomes pancake-thin.

By the way, the gain of the internal antenna of a 3g modem, depending on the model of the modem, has a negative gain ranging from -15 to -3 dBi.

Congratulations! Now you can choose the right antenna for 3G.

How to orient and install an external 3g antenna can be found here :.

And about "How to connect an external 3G antenna to the modem?" here: Adapters. Pigtails ...