Quite often, an Internet connection is provided by a USB modem. Such a device is quite convenient, takes up little space and allows you to have access to world wide web not only within the city, but also on vacation, in the country or on vacation. You will need a PC or laptop. The main thing is that the signal quality is distinguished by the stability and stability of the connection. However, often this important communication parameter does not meet the necessary requirements. Eventually weak signal interferes or even restricts Internet access.
What to do in this case? Let's start in order.
First, let's figure out what affects the signal level, the quality of the connection, thereby predetermining the effective operation of the modem?
First, this is the distance to the nearest tower. cellular communication... Secondly, the presence of others nearby wireless devicesthat may interfere. Nearby industrial enterprises, most of which use communication jammers, can also affect. Thirdly, it is the isolation of the room. It is one thing when a signal passes through wooden walls, thin plasterboard structures, and quite another if massive concrete partitions are encountered in its path. Fourthly, this is the location of the modem itself. 3G and 4G signals are much stronger near windows or on higher floors.
Precipitation can also reduce the data transfer rate: rain, snow, hail, fog, etc. Even the relief of the surrounding area affects: mountains, hills, tall trees, etc. We must not forget about software the computer or laptop itself. May be overwhelmed rAM or at hard disk contains a large number system errors, viruses, etc. Less often, problems with signal transmission are explained by problems on the tower base station... For example, the employment of slots, i.e. a large number of connected currently subscribers.
From all of the above, we conclude that the quality of 3G and 4G modem signal depends on a large number of factors. Not everything can be influenced by the user. However, by eliminating at least most of them, you will be able to significantly improve the data transfer speed.
How do I determine my baud rate?
Modem speed is easy to find with special online tests. You will need a computer, a browser and an Internet connection.
One of the simplest is the resource http://speed.yorest.ru/ Its principle of operation is that you download a small file, and the site, meanwhile, analyzes the data transfer rate. Here you can independently select the test parameters and the size of the control packet (200 KB, 1000 KB, 3 MB). It is best to stop at the largest document. The test takes longer, but the results are much more accurate.
Http://www.speedtest.net is a popular internet speed testing resource all over the world. By the way, its interface is the most attractive and informative. When entering this site, the nearest test server is automatically selected, which speeds up the procedure and positively affects the accuracy of the results. When testing the speed of data transfer on a 3G or 4G modem, be prepared for the fact that about 20 MB will be taken from your traffic.
This online service displays not only the speed of transmission and receiving information, but also analyzes the ping. This value is displayed in milliseconds and shows the server response time to your request. Ping is enough important indicator... Especially if you use programs like Skype or like online games.
If, with the help of such tests, it turned out that the speed of data transmission and reception is less than 80% of that stated in the agreement with the provider, then you need to contact the support service. If the speed is fully consistent with the promised indicators, but working with web pages seems painfully long to you, then you should think about a more expensive tariff.
How do I know my base station?
The problem of a constant interruption in the operation of a 3G or 4G modem is most often associated with weak level signal. Some users are identifying the cause of low internet speed in a simple way... If the data transfer rate is constantly low, regardless of the time of day, then the reason is the distance from the tower. If the speed improves at night and in the morning, then this is the congestion of the base station (BS).
Basically, a bad 3G or 4G signal is associated with a long distance from the base station to the user. Therefore, it is important to find out its position, which will make it possible to make special amplifiers or simply place the modem in that part of the room that is as close as possible to the BS. Advanced users, knowing the numbers of various BSs, will be able to configure the modem so that it connects not only to the nearest tower, but also to the one that has more free radio channels, thereby significantly improving the speed of the Internet connection.
The online resource http://cellidfinder.com will help you find your BS. You need to know only 4 parameters:
- Operator country code (MCC). For Russia, it is 250.
- The unique code of the operator itself, called MNC (Mobile Network Code).
- Local area code or LAC. This is a kind of unification of several base stations within one territory, which are served by one controller.
- The last parameter is CellID (CID). This is the identification number of the sector where the BS is located.
How do you know all these parameters? To do this, you can use the Netmonitor application or the web resource of the same name. By the way, on this site you can find a map showing the majority of BS in the central part of Russia belonging to the most popular telecom operators.
We learn through the netmonitor all the necessary values \u200b\u200band enter them in a special search box on home page http://cellidfinder.com. Next, put a checkmark in front of "Google data", "Yandex data" and "Averaging". Thus, the accuracy of determining the coordinates is increased. Press the button "Find". We look at the marked places on the map with the location of the BS.
Ways to enhance the modem signal
The most popular are:
- Installing a PC or laptop with a modem near a window;
- Using a USB extension cable and placing the modem on the windowsill or even on the street;
- Creation of a reflector, that is, a device that amplifies the signal (some craftsmen make it from pots and colander, someone uses speakers and frequency resonance);
- The use of a factory amplifier 3G or 4G signal (average cost 1000-2000 rubles).
Each of these methods can improve the signal quality by 10-30%. A complete lack of result cannot be ruled out. For example, a long USB extension cable can cause the modem to run out of power and stop being detected by the computer at all.
A repeater is an effective but costly solution. This is a 3G or 4G signal amplifier. Its undoubted advantage lies in the fact that it increases the speed of data transmission and processing not only of a particular modem, but also of several devices. When it functions within a radius of up to 50 m, cellular communication will also work better. We recommend purchasing a repeater to improve the signal in basements or basements.
An effective and cost-effective way to amplify the modem's signal is a special antenna, which is quite easy to make yourself. Let's look at some examples.
We assemble the antenna to amplify the modem signal with our own hands
- At home, you can simply amplify the 3g or 4g signal with your own hands. Especially often, these homemade antennas are used in the country or in a country house to enhance the signal level of cellular communications, including for receiving the Internet. The simplest antenna is made in a few minutes. A small winding of copper wire is taken, which is wrapped several times around the modem, and taken out closer to the window or outside the room by 40-80 cm. The number of turns must be selected based on the thickness of the device. The main thing is to wrap the part where the SIM card is located. You can put a tin can at the end of the wire. Is this construction effective? Quite. Expect a 5-10% increase.
- For another uncomplicated antenna, you need an empty metal coffee can. In the side part, right in the center, a hole is made into which we fix the modem. Ideally, the outside of the device protrudes about half or slightly less. Then we connect the modem via a USB extension cable and use the trial method to find a good place with the best signal.
- Quite often, to amplify the modem signal, a loop antenna is created that has a zigzag shape and resembles 2 rhombuses made of copper wire. Both have one point of contact with each other, consisting of two corners. It turns out an un-rounded "eight". On the Internet, this design is better known as the Kharchenko antenna. Next, a high-frequency cable is soldered to it (as for TV). It is best to solder part of the wire to the connector - it will look like a plug. The other end of the cable is stripped to wrap the modem itself (5-6 turns). To increase efficiency, it is worth equipping the antenna with a reflector - a metal or foil plate. We fix the structure as high as possible, for example, on the roof or on the top floor.
Nowadays, many people work directly on the Internet, they do not have to sit in an office to conduct their business. Many problems are solved through the network, so it is extremely important that a high-quality Internet signal is absolutely everywhere. If the cottage is located far enough from the city, plus the tower is not nearby, then you can not hope for high-quality Internet. But what to do in this case, not to go to the country? Build a tower near you? Everything is much simpler: you just need to make an Internet signal amplifier for a summer residence with your own hands.
A bit of theory
Before you learn how to make the best internet signal booster for a summer residence, you need to understand a little what 3G and 4G are, and what can cause a bad signal.
Not so long ago, many summer residents used satellite internet, but this technology has almost completely outlived itself, now the overwhelming majority of people use which gives a very good speed for comfortable work online. Today, there are three communication formats in Russia - 2G, 3G and 4G. As reported a little earlier, in 2 years, in 2020, the most modern format will appear - 5G.
To understand how the classification of communication formats differs, you need to know the following:
- 2G, aka EDGE, is the slowest mobile Internet, its speed does not exceed 40 Kb / s, today it is practically not used anywhere.
- 3G - the first high speed internet, thanks to which you can surf the pages very comfortably. The speed of this communication format does not exceed 800 Kb / s.
- 4G - today in Russia - the fastest mobile Internet, its speed is 2-5 Mb / s.
- 5G - since the introduction of such a format has not yet taken place, it is rather difficult to say exact numbers, but approximately the speed should be about 1 Gb / s.
These statistics are approximate, because theoretically the speed can increase for each of the points, it all depends on the operator's bandwidth.
Mobile internet signal booster for summer cottages
Each person can personally enhance the signal quality of the 4G modem, which can be purchased at any mobile phone store of the selected operator. To use the Internet through such a modem, you need a computer or laptop. But you should also take into account the factor of connection stability, if the operator is not able to maintain an uninterrupted signal (even at a low speed), then it is rational to simply change it. Otherwise, the user will still receive a poor-quality Internet connection.
There are several possible optionshow to amplify the signal. The most popular are:
- Extend the USB cable through which the modem is connected to a computer or laptop. Thanks to this, the modem can be placed somewhere higher or even taken out into the street, while the quality of communication will significantly improve.
- UTP extender for 3 or 4G modem. A regular USB extension cable will not work properly if the cord is longer than 4 meters. In this case, the extension cord can have a high-quality connection to the computer at a distance of up to 20 meters. Therefore, the modem can even be taken out on the roof of the house.
- Purchase a special internet signal booster. Not the cheapest way, because the cost complete set will cost about 2800 rubles. ($ 50), however, the end result is really worth the money.
- Make a special antenna with your own hands, which will improve the quality of communication.
- Change operator. At first glance, such a banal procedure may be the most effective.
- Select "3G only" or "4G only" mode.
We figured out the main methods of improving Internet connection, now in more detail about each of them.
Extend the modem via USB cable
To improve the quality of the signal, it should be understood that this is a wave that spreads unevenly in different parts of the house. This means that you first need to determine where the signal is strongest and most stable. This will take a little time and patience, when this place is determined, you should proceed to the next step.
Almost all modems display the dBm value, and it is worth paying attention to it. If this value is less than 70, the signal is simply excellent and this is where it is best to place an Internet access point. When the signal level is in the range of 70-80 dBm - an average indicator, if there is no better indicator in the house, then you will not notice strong discomfort when surfing pages. But when the dBm value is more than 100, the signal is very weak.
In practice, it is known that the strongest signal exists near windows and closer to the ceiling. It is best to place the modem somewhere near the roof. In this case, you should not worry about the device. All modems are not afraid of winds, rains and frosts, but exhibit a device where there is a lot sun rays, it is undesirable.
So, if the location is determined, now you need to head to the store and simply purchase a USB extension cable of the desired length. It is important to remember that if it is more than 4 meters long, then this procedure loses all meaning, the signal quality will be bad again.
UTP extender
If four meters of extension cable is not enough to seriously improve the signal quality, then in this case, you should purchase a special UTP extension cable. Such a device can qualitatively lengthen the modem up to 20 meters. Therefore, if the access point needs to be taken out to the roof, this is exactly what you need.
The extension cord consists of three parts:
- USB port that plugs into a laptop or computer.
- The port where the modem is connected.
- UTP cable that connects the two ports. You can use a classic UTP-5E cable.
But if 20 meters of cable is not enough for you, then in this case you should purchase a more expensive one. High-quality information transfer will be stable at a distance of up to 50 meters.
for giving
Often in stores you can see special antennas that are designed to amplify the signal. They are purchased together with the required amount of cable; the antenna should be installed on the roof of the house.
The difficulty of the installation lies in the fact that one person cannot do it. Before installing the antenna, you should choose its exact direction, in which direction the signal will be of the highest quality. The process goes something like this: one person slowly turns the Internet signal amplifier to give, and the second on the computer looks at the dBm frequency and where the value will be the lowest, in this direction the device should be fixed.
The antenna itself is connected to the modem, and the modem, already by cable, to the computer. It is also worth noting that the modem must be no further than two meters from the signal amplifier, otherwise there will be no result. There are also some more connection difficulties. Not all modems have antenna outputs, and those that do are of insufficient quality, so it is likely that you will have to re-solder the input yourself. If you do not know how to do this, then it is better to refer the modem to the craftsmen who soldered more than a dozen of such devices.
This method is very complicated and costly, moreover, the antenna must be grounded. However, in some cases, it is the antenna that becomes the savior. If the tower is far enough away (more than 10 km), then this is the only correct solution.
Antenna for amplifying the signal with your own hands
A homemade antenna can be used not only in the country, but also on a hike, it is quite simple to make it. You need to wind copper wire on a USB modem, how many turns you need to say is quite difficult, but there should be quite a few of them. Most of the wire should be wound where the SIM card is located. At the end of the wire, you need to make a small screen from an ordinary tin can, and if you have an unnecessary CD, then it is generally ideal for a homemade antenna. Such a simple Internet signal amplifier for a summer residence can improve the quality of communication by up to 20%, which is a very good indicator.
The second version of a homemade antenna
There is also a stationary version of the antenna. Two rhombuses should be made from a sufficiently thick copper wire. In appearance, the antenna should resemble an unrounded figure eight. Solder the usual one to the place of joints of rhombuses antenna cable, wrap the modem with the other end of the cable, as indicated in the previous example. Mount the antenna with the modem on the roof of the house or put it out the window, and connect the modem to the computer when uSB help or UTP extender.
Operator change
The quality of the Internet signal directly depends on the proximity of the towers located and the quality of the equipment. Therefore, before tinkering with something, it is worth trying to simply change the operator, sometimes this is the simplest and most effective method of signal amplification.
User opinion
And what do they say about what he really is - the best Internet signal amplifier for giving, user reviews? Of all the methods described above, people most often prefer conventional extension cords. In most cases, they are the ones who help solve the problem. Also, many people respond well to purchased antennas. As for homemade devices, then opinions are divided. Some do-it-yourself antennas helped, while others complain that there was no improvement in the signal at all. However, do not forget that people could simply not adhere to the instructions or it is corny to do something wrong.
High-speed Internet is becoming more and more available, and perhaps in a few years, even a resident of a remote area will be able to use it. But now those who live outside the city, or even just in small villages, have to be content with alternative options, one of which was the use of a 3g modem. As a rule, it catches the network quite well, being close to the transmitting base station, but as it moves away from it, the signal level will decrease. An antenna for a 3g modem, assembled from handy materials, can help to strengthen the signal.
The fact is that even if there is a desire to buy a factory version, it is not always possible to do this, and not every modem has additional inputs for connecting an external antenna. You can, of course, start soldering wires directly to the board, but if we are already engaged in such an intervention in its device, then it is worth trying. There are several basic options for such antennas, and how to implement them.
Types of homemade antennas for a 3G modem
Antennas can be divided into omnidirectional and directional, that is, "looking" in a specific direction. The latter, of course, require knowledge of at least the side where the stronger signal comes from, but this is also solved by a conventional check by gradually scrolling it around its axis.
Among the most famous industrial models, which are much less often used for self-assembly, has become a 3g panel antenna. It is a little more difficult to assemble it with your own hands than other options, but due to the design features, in some cases the factory version was still preferable.
A yagi antenna is time consuming, but when properly assembled can greatly increase signal strength. Not recommended for users who are not very confident in their hands.
The Kharchenko antenna is a lighter option than the above, and requires less materials. Another advantage is the size, which may be several times smaller than that of the yagi antenna.
The last method of manufacturing can be called the elementary use for this purpose of an ordinary coffee can, or other drinks. In one of the past articles, a similar device was mentioned.
DIY 3g yagi antenna
Of the materials for making the antenna, you will need: a metal rod with a diameter of 18 mm, electrodes with a diameter of 4 mm, a plastic clothes hanger (79 mm) and a T-shaped PVC pipe connector as a holder for the future vibrator, self-tapping screws.
The vibrator is made by cutting off the top of the plastic hanger as shown. Then it is inserted into the holder, which will subsequently be screwed onto the rod using self-tapping screws.
We mark the places for the electrodes on the rod, which as a whole will make up the reflector. Its length will be 81 mm, distance from the beginning of the rod: 30 mm. We drill holes for the electrodes, which will then be tacked into them by welding, so that the structure shown in the figure is obtained. This whole system of teeth is a do-it-yourself 3g yagi antenna reflector.
The last point is to make an antenna loop for the vibrator. In principle, it can be made separately, and installed at the beginning of the process - as it is more convenient for anyone. In any case, it is created from an ordinary wire, and does not look like something particularly complicated. It connects the vibrator and the last of the reflector electrodes.
The finished one is then attached as high as possible above the ground, or a pin-base can be attached to it, similar to those used on simple television antennas... Here you can not think about the diameter of the material and the like - the most important thing will be its very composition. It is impossible that it could cause interference in signal reception for the 3g modem.
Antenna Kharchenko for 3g modem do it yourself
Antenna Kharchenko is also called "eight" and there are no difficulties in its manufacture. The basis of the design, which draws attention to itself, is a curved wire, for which the antenna is called "figure eight". A regular 4 mm wire is bent as shown in the figure, and its ends are soldered together. We observe the angle between the antenna walls, which is 120 degrees. The length of the side wall is 53 mm, and the distance between the points at which the two squares of the antenna connect should be 5 mm. In no case do we bring it to a smaller size, or even more so to zero.
We look for, or make our own plate of aluminum 2 mm thick. The length of each side is 140 mm. In the center, you need to drill a hole for the coaxial cable, which will go from the wire element of the antenna to the modem. We attach the wire itself parallel to the plane of the plate at a distance of 36 millimeters. For fastening, holders are used made of non-conductive materials, for example, plastic stands.
We pass the cable through a hole in the plate, and connect the conductors to each of the two points of the figure eight at the junction of the “squares” - to the very points between which we left a distance of 5 mm before. It remains only to connect the opposite part of the cable to the modem.
It remains to "dress" the modem with copper foil, which is sold in the radio store. We cut out a piece, 45 mm long and of a suitable width in order to wrap the modem with it several times, and solder it so that it does not come apart. A wire will be fed to this base. Now, from the same foil, the braid for the modem with sides of 27 and 76 mm. It is important that later it itself does not touch the central core connected to the foil on the modem. We do as in the figure below, and we achieve the appearance of a stable signal.
Antenna for 3G from a can
Probably the simplest version of a directional 3g antenna with your own hands is a design made from a simple can. In previous articles, it was told about how to make an amplifier for wi-fi in a similar way - here is about the same design, but only it works for reception, not transmission.
A hole is made in a metal can, into which the modem itself is inserted, or, if it has a corresponding socket for an antenna, the end of the TV cable connected to it. The length of the protruding part inside the can is about 36 mm with a can diameter of 100 mm. In this case, the hole should be placed in the last third of the can, at a distance of 65 mm (for our case).
With the resulting antenna, it remains to walk around the room in order to catch the direction of the signal, and, if possible, hang it higher for a more stable connection. In cases where there is no signal at all, can antenna is unlikely to help, but to strengthen the already existing - quite.
Almost everyone knows that the 3g network has already covered almost all countries. Russia is no exception. Such inscriptions on the display mobile phone like WCDMA - HSDPA and 3G we can see every day, but in addition, 3G modems that operate at frequencies from 900 to 2100 MHz are no longer included in the "new" category.
All mobile operators began to sell modems under their own logo, but be that as it may, each of them is the E1550 model from Huawei. But when connecting, difficulties arise due to the fact that high-frequency transmissions are characterized by short distances, therefore the built-in antenna cannot always pick up the 3G signal. The way out of this situation is EDGE and GPRS, which, unfortunately, cannot boast of their high operating speed, or a 3G signal amplifier that effectively amplifies the 3G signal.
Purchase the required antenna rather difficult, because the solution may be DIY 3g antenna... After all, many modems do not have special connectors for antennas, so they can cost about two thousand rubles, i.e. the cost of the antenna is approximately three times the cost of the modem.
For example, I myself never thought at all that the area where my village is located (on weekends I go there periodically) would be covered with third-generation networks, so I used the Internet through which I could not please with its speed. But once I decided to use the normal speed, after all, I don't live in ancient times. I decided to read about third generation networks in more detail and came to the conclusion that, judging by the 3G coverage map, I can use normal Internet.
On one of the sites, I calculated a square-law antenna that was created for wi-fi under 3G. Everything is quite simple, with the help of a small program, the calculation is made in a few keystrokes. You can download the program.
So, I needed:
- RG6U wire with a connector for it;
- A piece of copper wire from 1 to 4 mm thick;
- Shaving foam cover;
- Solder, soldering iron, rosin and tool skill;
- A piece of plywood measuring approximately 120 x 134 mm and a piece of foil.
The first step is to take a piece of wire and fold it into two squares. One side will be approximately fifty-three millimeters.
Then we solder the two ends of the two squares, and apply the solder to the opposite corner. We clean the antenna wire with the connector and make the core of the wire so that it looks out about a centimeter from the connector.
Then, at the side of the connector body, you need to solder the core of the wire, this is important, because not everyone is able to solder the wire braid itself with rosin. Now you can proceed to the pins that go from the connector to the squares.
For better receptionTo make a reflector, you need to take plywood and wrap it with d foil, and make a hole for the wire in the middle of the structure. But it is necessary that the frame is above the reflector at a distance of about 35 millimeters, it is for this operation that we need a shaving foam cover. We cut out one centimeter grooves in it to position the antenna at the required height, about 4.5 centimeters.
A reflector must be placed behind the resulting structure. The antenna is ready.
If the modem does not have an input for our antenna, we will connect using the antenna-to-antenna method. It turns out that our antenna will receive a signal from another design, which acts as a repeater. Therefore, from the other end of the wire that comes from the antenna, you need to protect the core by about 10 - 15 cm. But so that we can get the most strong signal, it is necessary to attach a strip of 7 - 9 cm of foil to the end of the braid of the wire, bending it according to the type of circular polarization.
Then it remains to wind the wire in turns and stick it into the modem.
Let's move on to the verification process.
First, you just need to connect the modem to your computer and see if there is a signal level.
The biquad antenna was proposed by K.P. Kharchenko (1961) to catch meter television channels. Of course, it was large in size: the wavelength was not very small. When an antenna for a modem is required, assembled by hand from improvised means, it is often possible to fit the structure in a round box from under laser discs, the reflector in this case is easy to install. One blank is enough, the main thing is to look at the light so that it is not transparent (a metal layer is required to construct a reflector). This means: the coating fits perfectly, reflects waves perfectly digital communication... We are talking about antennas for a modem - it means two standards WiFi, 3G. First mastered the frequencies household appliances, interferes with microwave ovens, the second is the brainchild of cellular communications. The wavelengths are, of course, similar.
Digital modems
The word modem is a derivative of two others:
- Modulator.
- Demodulator.
When transmitting information packets, you have to encode. Practitioners quickly discovered that if a person's speech was broadcast on the air, the broadcast would fade out at a distance of 25 meters. Low frequency radio waves are not viable. The situation is better with wires. It is well known: analog telephony was able to transmit speech for kilometers, using amplifiers, the scope can be extended. However, in this case, the conditions are foreign to ideal. Why is this nonsense. Each medium (air, iron, water) is endowed with a characteristic of throughput, and the amount of losses depends on the frequency. Communication windows (transmitting electromagnetic radiation) used by satellite broadcasts. The WiFi range (2.4 GHz) is not relevant, on the contrary, radiation is absorbed by water vapor.
Thinking in this way, the engineers gave birth to the idea: information can be conveyed by encoding a useful signal the parameter of the carrier wave entering the transparency window. On the receiving side, the information needs to be decoded. Modems do this. Light, electromagnetic waves are transmitted in the line, encoded useful information... The antennas are busy converting electrical vibrations into an etheric wave that propagates through space. This step eliminates the need to install a communication line, wire. The ether will serve to transmit information. Conveniences have to be paid for, in our case the range is severely limited, in addition, 99% of the energy is wasted if a pair of directional antennas are not used, aimed at each other. Broadcast wiFi network, 3G inevitably leads to losses. However convenience mobile communication pays off energy.
When will it help external antenna for modem:
- On the balcony we see the reception, inside the apartment there is silence. The signal is caught by the windowsill, inside the room - a round zero. The situation is a scourge wireless networks for one simple reason: the power of transmitters is limited by laws. Electromagnetic waves are harmful to health, despite the desire of officials to profit, sometimes you have to give in to the elementary requirements of doctors. Not sick, others - developing laws regulating the use of hazardous drugs.
- Several towers are broadcasting - residents are faced with such a situation: a modem flavored with a smart driver stubbornly imposes a connection on a point that is transmitting worse. In the best case, it is possible to re-throw manually, even it gets boring at times. A directional antenna will help out and aim it in the right direction.
- In the penumbra zone, the reception of WiFi, 3G signals is uncertain, determined by the vagaries of the weather. A directional antenna aimed towards the broadcasting helps.
There are other cases. Wherever you need to improve the quality of reception, you need a homemade antenna for the modem. True, one device has been invented to increase the signal level. We mean a reflector. Customers saw a 3G amplifier in the store, representing a cylindrical surface: a modem-flash drive was installed along the axis. The beams were collected in the center, improving reception. The device is passive, the price exceeds a modem with a half-year Internet package. No wonder the question of the townsfolk the size of a mountain, how an antenna for a modem can be made with their own hands.
Modem antenna designs
Let's start with the Kharchenko biquad antenna, suitable for all digital communication ranges. The instance catching WiFi fits in a box of laser discs, convenient in terms of weather protection. Would recommend to use online calculatorsmaking calculations. Since it is quite difficult to find, they took the trouble to calculate the parameters for some cases, then readers will generalize to any frequency, because the relationships will become obvious. WiFi Frequencies:
- Frequency 2.6 GHz, wavelength 115.3 mm. The side of the square is a quarter of the wavelength: 28.82. To get the total length of the figure eight, multiply one side by 8, we get 230.6 mm. We take a stock, it turns out 235 mm. The distance to the reflector will be 0.15 - 0.2 wavelength. We take something in between - 0.175. It turns out 20.2 mm.
In fact, the 2.45 GHz wave is often used. Let's make the calculation.
- The frequency is 2.45 GHz, the wavelength is calculated by dividing the speed of light by a number. The approximate speed of light in vacuum is 3 x 10 8 m / s, the exact value is 299792458. We calculate the wavelength… it turns out 122.36 mm. Next, we are calculating the beaten track. We get the side of the square by dividing the wavelength by 4 - 30.6 mm. The length of the wire is calculated by multiplying by 8, it turns out 245 mm, we take the reserve - 250. The distance to the reflector will be 112.36 x 0.175 \u003d 21.413 mm.
It is difficult to bend the wire at right angles. We recommend using a vice, pliers, hammer in the manufacture of an antenna for the modem. Along with a ruler and a corner, of course. Many people have a question about how thick the wire itself should be. Let's try to answer! Reducing the frequency the diameter increases, at 2600 MHz the parameter is 2.75 mm; mastering 1300, therefore, you should take 5.5 mm. Here are some values:
- 900 MHz - 8 mm;
- 800 MHz - 9 mm;
- 1800 MHz - 4 mm;
- 1900 MHz - 3.8 mm.
Similarly, we get the result for any frequency. It is clear that a violation of the thickness, moving away from the calculated values \u200b\u200bwill not lead to fatal consequences, however, you should not get too carried away. In order not to say later that the VashTechnik website contains incorrect values \u200b\u200b... According to our information, the GSM 1800 standard is often used on the territory of the Russian Federation, let's see which biquad antenna Kharchenko must be on a working frequency (3G modem).
The frequency is 1800 MHz, we find the wavelength: 299792458/1800000000 \u003d 166.6 mm. We find the side of the square by dividing by 4, it turns out 41.6 mm. The total length of the wire is 333.1 mm. With a margin, 335 mm will come out. The distance to the reflector is 166.6 x 0.175 \u003d 29.15 mm. Wire thickness is shown above. Design for health.
We will wait a little longer to consider other wavelengths, the calculation procedure is obvious. Here are a couple of notes on the design of a homemade antenna for a modem. If there is one biquadrat (and we will meet more), it resembles an eight - no more. There is no intersection at the center point. It's just that the wire approaches without touching, then scatters again to the sides. Reminiscent of, indeed, a figure eight on one side (WiFi vertical polarization). For the other polarization - horizontal - place the figure eight vertically.
It is better to take an insulated wire for the antenna. A cable core of the required thickness will do. The material does not have to be copper, it is just that the Olympic metal is not subject to electrochemical corrosion (it is always an acceptor). You need to protect the structure in any case. As stated above, wiFi models are placed in a box of laser discs, which we glue to be sure.
The figure 8 stands on insulated posts that can be placed anywhere, but it is easier to use two supports in the convergence area (in the middle). One edge connects to the cable and antenna screens, the other serves to pick up the signal. Both leads are close to each other, almost touching, there is no electrical contact at the intersection.
The signal gain will increase if you use two biquads. The central part is performed in the specified way, then the eights intersect (!) Crosswise, but at the point of contact, the two wires are reliably isolated from each other. The radiation pattern narrows, increasing the gain. Good methods of catching a tower that can be seen on the horizon. It will be possible to direct the antenna of the modem precisely - the reception will certainly improve.
The device is connected with a standard 50-ohm cable. Ideally, it is a good idea to measure the SWR, then bring it to a value less than 2. The device of the antenna for the modem may be different, in a recent review, designs resembling those used cell phones... Radiating pads united by matching lines.
Finishing the review, we emphasize: cellular communication standards, WiFi resemble each other. In both cases, the polarization is vertical. Made for confident reception at any point. When the wave propagates around the planet, the configuration is preserved. Vertical polarization is perpendicular to the ground. When talking on the radio, try to hold the antenna in this way.
Practice! It is known for certain that dull individuals tend to perform the simplest procedures incorrectly. Acting for show, they hold the walkie-talkies horizontally, twisting in an unthinkable way. Stick to proven solutions. Sometimes it's easier to take a couple of steps. The beam rarely changes polarization, otherwise the broadcasting industry would have long ago taken into account the nuance (car radio, for example).
