Powerful Wi-Fi antenna-gun. Homemade Wi-Fi antenna

Now in amateur radio practice, antennas for amplifying 3G, 4G, Wi-Fi signals of the “Biquadrat” type are very common.

Such an antenna has a directional effect, which may not always be an advantage, but even a disadvantage. An example is this: you need to strengthen the signal of your router so that you can catch it in any part of your house. If you use a directional antenna, the signal will most likely be well accessible only within the field of action of this antenna. Surely there will be only one room where it will be directed. It is good to use such an antenna only for long-distance communications, provided that you know where to point it.
To strengthen your WI-FI signal in all directions, an antenna is suitable, which I will show you. Its directivity characteristics are close to those of a whip antenna, with the exception of greater sensitivity.
In structure, this is actually the same biquadrate, only twice directed in opposite directions. Plus, this antenna is many times simpler than a classic biquad antenna, since it has neither a stand nor a reflector.

How to calculate an antenna?

Making a simple DIY Wi-Fi antenna

Antenna tests

An antenna for a WIFI router is a radio device designed to receive and transmit wireless WIFI Internet signals. WIFI antennas are connected to a transmitter or receiver (laptop, PC, etc.) using antenna cables and WIFI adapters (amplifiers).

WIFI antennas emit signals in all directions. But in real conditions, the efficiency of signal transmission in different directions is not the same. The directional properties of an antenna are characterized by the radiation pattern. The simplest radiation pattern is that of an omnidirectional WIFI antenna, which emits the same energy in all directions. For WIFI antennas, there are circular, sector and narrow directional patterns (BP). Directional patterns are depicted in the form of two sections - vertical and horizontal.

WIFI antennas are directional and omnidirectional, internal and external. Important parameters of WIFI antennas are directional coefficient (DA), gain (GA), input impedance and operating frequency band. WIFI antennas operate in the 2.4 GHz band.

The standard antenna for a d link router almost always has a gain of 2dBi.

If you need wireless coverage of a large area (an area in front of an office or a yard), then you need a router with an external antenna. It is designed in a strong waterproof case and can withstand bad weather, wind, and temperature changes. Such antennas are mounted on masts or brackets.

Internal WI-FI antennas are compact. They are extremely convenient for working indoors.

Omni-directional antenna

The omnidirectional antenna is most often used in wireless networking equipment. Such an antenna is characterized by uniform coverage of the territory throughout its entire range. Basically, an omnidirectional antenna is a rod that is mounted vertically. In this case, the signal propagates in a plane perpendicular to its axis. Such antennas, in comparison with directional ones, have a noticeably lower gain.

Antenna gain – 8 dB, length – 520 mm, diameter – 19 mm. The antenna is conveniently located on a mast, on the roof of a house or car. The antenna power is enough to operate at a speed of 1 Mbit within a radius of up to 1800 meters, and 54 Mbit – up to 600 meters.

Directional antenna

This antenna is well suited for a point-to-point network. For a computer that must connect to an access point or to another computer, it is better to use a directional antenna. Such an antenna can “break through” even impenetrable walls.

An example of such an antenna is the WAN-2118 Yagi antenna. The gain of such an antenna is 18 dB.

The antenna provides reception at speeds of 1 Mbit/s - up to 5 Km, 54 Mbit/s - up to 1.5 Km.

Homemade antenna for a router

There are many options for making Wi-Fi antennas yourself. A home-made antenna for a router will not be inferior in terms of characteristics to the purchased model. For example, let's take the production « attachment antennas » . HF radiation is supplied to such an antenna without the use of a cable. The antenna is attached to the standard whip antenna of the Wi-Fi router.

First, let's determine the antenna parameters. Wi-Fi uses several channels (frequencies). The first channel operates at 2412 MHz, the second – 2417 MHz, the third – 2422 MHz, etc. Each channel is shifted relative to the previous one by 5 MHz. Therefore, knowing the operating frequency of the router, you can calculate the antenna dimensions. For example, let's take the sixth channel - 2437 MHz . and we will perform the calculation for it.

Antenna parameters can be calculated using the mmana-gal program, and you can download it from this link: http://depositfiles.com/ru/files/2zjnh48lu

This program can simulate almost any antenna, and a large library of ready-made antennas is built-in.

The main radiation is concentrated in the direction of the wave channel. To make an antenna, you need half a meter of wire with a cross-section of 1.5 sq. mm, a piece of corrugated packaging material and a pen cap (its diameter should be slightly larger than the diameter of the router’s Wi-Fi antenna).

It is necessary to cut a strip of cardboard 150x20 mm (the supporting part of the antenna). According to the dimensions in the figure below, you need to cut the antenna vibrators from the wire and assemble the entire structure.

After this, you need to put the assembled “attachment” on the standard Wi-Fi router antenna and orient it in the required direction.

DIY WIFI all-weather access point

This is an easy to manufacture and very powerful Wi-Fi antenna like a cannon. With its help you can receive and transmit a Wi-Fi signal not only over hundreds of meters, but over several kilometers!
The antenna-gun resembles the appearance of a space blaster and, just like this fantastic weapon, has a directional and very powerful effect.

This is a directional antenna. And it is this property that gives a long reception distance due to the large concentration of the signal in one direction.

Antenna diagram

To make an antenna you will need

• Long stud with nuts.
• Metal sheet, I took copper because it is very easy to cut. In general, you can take tin from cans.
• . But you can connect to an existing router.

Making a powerful Wi-Fi gun antenna

Add-ons

Wi-Fi is a technology that can only function normally within line of sight. Wireless networks are easily lost among walls, furniture and other obstacles in the apartment. Moving an adapter or router around the house in order to increase the efficiency of appliances is not always possible. A more correct approach is to use an external, more powerful antenna - the active part of the transmitting/receiving device.

Types of Wi-Fi antennas

In terms of use, all Wi-Fi antennas are divided into two classes:

• for outdoor use (outdoor),
• for indoor use.

These antennas differ primarily in their size and gain. The outdoor class implies large sizes and the ability to attach to any support (surface). High gain in such antennas is achieved by design features. Such devices are usually used for wireless data transmission between points that are located at a considerable distance from each other. It is preferable to install them in line of sight.

Depending on the type of antenna, Wi-Fi is characterized by a higher or lower gain - one of the most important parameters of any receiving and transmitting equipment

Indoor class antennas are designed for indoor use; they are smaller in size and do not have outstanding gain and power. Internal antennas are attached either directly to the transmitting/receiving gadget, to the wall, or placed on the surface. The antenna is connected to the device board either directly or via a cable.

Additional Wi-Fi antenna in an apartment or house

The main reason for needing an additional Wi-Fi antenna is to strengthen a weak signal. This situation may arise in the following cases:

• The Wi-Fi access point is located at a considerable distance (if the room is large), there are obstacles (walls, ceilings);
• The router is not powerful enough.

Also, an additional Wi-Fi antenna may be needed if you need to organize a “router - several client points” network, or if you need to connect several PCs together “over the air”.

DIY making

On the Internet you can find many recommendations for making various types of Wi-Fi antennas at home. As a rule, replicating most designs does not require deep knowledge of radio electronics, scarce materials or specialized tools. You can make any of the Wi-Fi antennas using the instructions below in just a couple of hours.

Double biquadratic

The “double square” antenna for Wi-Fi and its modifications are the most popular on the network. The classic biquad has good gain and a wide radiation pattern. The dual biquad antenna, discussed below, has even better performance.

To repeat the design you will need:

• copper core (wire) with a cross section of 2 mm;
• a small sheet of aluminum 1–2 mm thick;
• a piece of rubber (vinyl) tube, plastic ties;
• soldering iron, solder, rosin, drill, drills, pliers;
• cable for connection.

Making an antenna is not difficult, the main thing is to accurately maintain the dimensions, since even small deviations threaten to shift the operating parameters:

1. We draw a sketch. The length of one side of each square is 30 mm, the dimensions of the reflector are 220×100 mm, the distance between the active part and the reflector is 15 mm. We mark the holes.

   Double biquad - an improved version of the classic biquad antenna

2. We bend the copper core strictly in accordance with the template. We clean (if the wire is varnished) and solder the ends.

   Even a small error in size (literally a couple of millimeters) will worsen the quality of the antenna.

3. We make a reflector from a sheet of aluminum. We drill holes with a diameter of 3–4 mm.

   The reflector can also be made from a copper plate or (at worst) a steel sheet

4. Using plastic ties through rubber tubes, we fasten the active element of the antenna to the plate.

   The antenna mounting posts to the reflector must be made of non-conductive material

5. We secure the adapter (or cable, if the device is located remotely) with plastic ties. Solder the removed wires. The distance between the contacts is 5 mm.

   The adapter should be attached as securely as possible, but carefully so as not to damage the device

The advantages of this design include:

• easy and fast production,
• Significant signal amplification and stable operation.

Perhaps the only drawback of such an antenna is that even small deviations from the required dimensions threaten to reduce its efficiency.

From an aluminum can

This design, of course, cannot be called a full-fledged antenna (essentially, it is a reflector), but to some extent it is capable of strengthening a weak Wi-Fi signal.

What you will need:

• empty aluminum can,
• knife and scissors,
• a piece of plasticine.

In terms of ease of manufacture, an antenna made from an aluminum can has no equal:

1. Rinse the jar. Cut off the bottom with a knife.

   Be careful when carrying out work, health is more valuable than even the highest quality Wi-Fi antenna

2. Make a cut at the top, but not all the way - leave a 1.5–2 cm long section uncut.

   You can also break off the opener at this stage.

3. Use scissors to cut the can lengthwise from the back side.

   An aluminum can can be easily cut with any scissors, as long as the latter are sharp enough

4. Bend the metal.

   The opening angle can be selected experimentally after installation, focusing on the Wi-Fi signal level

5. Attach the reflector to the device using plasticine, placing it on the standard antenna of the router. Point in the right direction.

   In the absence of plasticine, use chewing gum

Advantages of an antenna made from an aluminum can:

• ease of manufacture,
• absence of scarce materials,
• universality (will work with any router with an external antenna).

Among the disadvantages, it is worth noting insufficient signal amplification and unstable reception/transmission directionality.

Powerful sheet metal antenna

Wi-Fi antenna made of sheet metal, known as FA-20, is characterized by increased power and can be used to receive signals from remote (up to several kilometers) access points.

To make it you will need:

• sheet metal;
• powerful soldering iron (100 W), solder, flux (soldering acid);
• dielectric stands, fasteners (screws, nuts);
• drill, drill bits;
• connection cable;
• metal scissors, wooden hammer, fine sandpaper, pliers.

Replicating the design requires at least basic plumbing skills.

FA-20 manufacturing instructions:

1. Using metal scissors, we cut out quadrangles and strips, strictly observing the indicated dimensions. It is advisable to sand the edges.
   

   Antenna parts are cut out individually and then soldered together

2. We solder the antenna elements. We use solder and a special flux for soldering. It is more convenient to do this on a wooden surface.
   

   Soldering of tin elements should be carried out in a well-ventilated area

3. We wash the finished structure under running water to remove acid. We drill holes with a diameter of 3–5 mm.
   

   If necessary, level the antenna with a wooden hammer (mallet)

4. We make a box. Dimensions - 450×180 mm. The height of the sides is 2–3 cm. If you do not have the skills of a tinsmith, in principle, you can do without the sides (losing a little in sensitivity) by simply cutting out a rectangle. We drill holes in it that coincide with the holes of the active elements. We fasten the parts on the racks, the distance between the parts is 20 mm.
   

   Support posts must be made of insulating material

5. We solder the cable: the red dot is the central core, the blue dot is the common (screen).
   

   To connect the antenna to the router, a regular television cable will do.

Advantages of a homemade antenna made from sheet metal:

• high power,
• good focus,
• no scarce or expensive materials are required for manufacturing.

A significant disadvantage of the FA-20 is the complexity of its manufacture. In addition, the antenna is quite large and is most likely suitable for installation on a roof or balcony.

DIY Wi-Fi antenna variations

On the Internet, among the huge variety of homemade Wi-Fi antennas, the most common is the so-called “double square” and its variants. However, you can also see a lot of crafts that differ from the classics.

You can choose and try to make any of the antennas, but you should remember that not all of these products are truly highly efficient, as the authors claim.

Photo gallery: other homemade designs

The MIMO antenna has two circuits inside one housing and, accordingly, two connectors for separate reception and transmission. This variation of the biquad antenna amplifies the signal many times over. The reflector of the biquad antenna is often made of foil fiberglass. The Wi-Fi disk antenna is highly directive and can be used both indoors and outdoors. so on the street The antenna made from cans looks original, but in fact it is not a very effective design. The petal steamer in this design can be replaced with a colander or an iron bowl

Connection

The method for connecting the Wi-Fi antenna depends on the type of router, adapter or other device you are using. In most cases, you will have to open the gadget, find the place where the standard antenna is connected (soldered), and similarly attach (solder) a homemade cable. It is very convenient when the gadget provides an independent connection for an external antenna; this can be done in the form of:

• connector in the battery compartment, on the back cover of the device, inside the case, etc.;
• the so-called pigtail (usually located directly on the device board).

If the adapter has a removable standard antenna, a homemade design can be connected instead.

In any case (excluding the option with soldering), you will need an appropriate connector, which can be purchased at a radio store. You are lucky if your router has an output for connecting an external antenna headset You can install the pigtail socket on the gadget body yourself if you are confident in your own abilities A tiny connector on the device board is used to connect a special pigtail extension cord Sometimes the fastest and most reliable option is to solder the cable instead standard antenna

Settings

Setting up a homemade Wi-Fi antenna comes down, first of all, to installing it in the right direction. In this case, the following conditions must be observed:

• take into account the signal propagation vector of the Wi-Fi signal receiver/transmitter;
• take into account the presence of barriers between transmitting and receiving devices;
• take into account that hard surfaces reflect the signal, while soft surfaces, on the contrary, absorb it;
• If possible, install the antenna within line of sight relative to the receiver/transmitter.

For greater efficiency, the antenna should be directed towards the access point.

At the setup stage, the cable length should be reduced as much as possible, this way you will get rid of unnecessary signal losses and improve its quality.

How to test changes

The simplest and most affordable option for testing a homemade Wi-Fi antenna is to measure changes in the speed of the Internet channel. To do this, a comparative study of the results is carried out alternately with a connected standard antenna and a self-made one. You can carry out such measurements, for example, on the Speedtest resource. The system will automatically select the optimal server, check ping, download and upload speed.

Video: Do-it-yourself Wi-Fi signal strengthening

With the advent of Wi-Fi, many users have the opportunity to quickly and mobile access to the Internet. For stable operation of a wireless connection, it is recommended to use special, expensive equipment, but you can get by with little expense by assembling an external antenna with your own hands.

If you want to assemble a long-range WiFi antenna, then you should know about some of its features.

The first and simplest: large antennas of 15 or 20 dBi (isotropic decibels) are the maximum power, and there is no need to make them even more powerful.

Here is a clear illustration of how, as the antenna power in dBi increases, its coverage area decreases.

It turns out that as the antenna’s operating distance increases, its coverage area decreases significantly. At home, you will have to constantly catch a narrow band of signal activity if the WiFi emitter is too powerful. Get up from the couch or lie down on the floor, and the connection will immediately disappear.

That's why home routers have conventional 2 dBi antennas that radiate in all directions - so they are most effective over short distances.

Directed

9 dBi antennas only work in a given direction (directional) - they are useless in a room, they are better used for long-distance communications, in the yard, in the garage next to the house. The directional antenna will need to be adjusted during installation to transmit a clear signal in the desired direction.

Now to the question of carrier frequency. Which antenna will work better at long range, 2.4 or 5 GHz?

Now there are new routers operating at double the frequency of 5 GHz. These routers are still new and are good for high-speed data transfer. But the 5 GHz signal is not very good for long distances, as it fades faster than at 2.4 GHz.

Therefore, old 2.4 GHz routers will work better in long-range mode than new high-speed 5 GHz ones.

Drawing of a double homemade biquadrat

The first examples of homemade WiFi signal distributors appeared back in 2005.

The best of them are the biquad design, which provides a gain of up to 11–12 dBi, and the double biquad design, which has a slightly better result of 14 dBi.

According to usage experience, the biquadrate design is more suitable as a multifunctional emitter. Indeed, the advantage of this antenna is that with the inevitable compression of the radiation field, the signal opening angle remains wide enough to cover the entire area of ​​​​the apartment when installed correctly.

All possible versions of a biquad antenna are easy to implement.

Required Parts

• Metal reflector - a piece of foil-textolite 123x123 mm, a sheet of foil, a CD, a DVD CD, an aluminum lid from a tea can.
• Copper wire with a cross section of 2.5 mm2.
• A piece of coaxial cable, preferably with a characteristic impedance of 50 Ohms.
• Plastic tubes - can be cut from a ballpoint pen, felt-tip pen, marker.
• A little hot glue.
• N-type connector - useful for conveniently connecting an antenna.

For the 2.4 GHz frequency at which the transmitter is planned to be used, the ideal biquadrate size would be 30.5 mm. But still, we are not making a satellite dish, so some deviations in the size of the active element - 30–31 mm - are acceptable.

The issue of wire thickness also needs to be considered carefully. Taking into account the selected frequency of 2.4 GHz, a copper core must be found with a thickness of exactly 1.8 mm (section 2.5 mm2).

From the edge of the wire we measure a distance of 29 mm to the bend.

We make the next bend, checking the outer size of 30–31 mm.

We make the next inward bends at a distance of 29 mm.

We check the most important parameter of the finished biquadrat -31 mm along the center line.

We solder the places for future fastening of the coaxial cable leads.

Reflector

The main task of the iron screen behind the emitter is to reflect electromagnetic waves. Correctly reflected waves will superimpose their amplitudes on the vibrations just released by the active element. The resulting amplifying interference will make it possible to propagate electromagnetic waves as far as possible from the antenna.

To achieve useful interference, the emitter must be positioned at a distance that is a multiple of a quarter of the wavelength from the reflector.

Distance from emitter to reflector for biquad and double biquad antennas we find lambda / 10 - determined by the features of this design / 4.

Lambda is a wavelength equal to the speed of light in m/s divided by the frequency in Hz.

Wavelength at a frequency of 2.4 GHz is 0.125 m.

Increasing the calculated value five times, we get optimal distance - 15.625 mm.

Reflector size affects the antenna gain in dBi. The optimal screen size for a biquad is 123x123 mm or more, only in this case can a gain of 12 dBi be achieved.

The sizes of CDs and DVDs are clearly not enough for complete reflection, so biquad antennas built on them have a gain of only 8 dBi.

Below is an example of using a tea jar lid as a reflector. The size of such a screen is also not enough, the antenna gain is less than expected.

Reflector shape should only be flat. Also try to find plates that are as smooth as possible. Bends and scratches on the screen lead to the dispersion of high-frequency waves due to disruption of reflection in a given direction.

In the example discussed above, the sides on the lid are clearly unnecessary - they reduce the signal opening angle and create scattered interference.

Once the reflector plate is ready, you have two ways to assemble the emitter on it.

1. Install the copper tube using soldering.

To fix the double biquadrat, it was necessary to additionally make two stands from a ballpoint pen.

1. Secure everything to the plastic tube using hot glue.

We take a plastic box for discs for 25 pieces.

Cut off the central pin, leaving a height of 18 mm.

Use a file or file to cut four slots in the plastic pin.

We align the slots to the same depth

We install the homemade frame on the spindle, check that its edges are at the same height from the bottom of the box - about 16 mm.

Solder the cable leads to the emitter frame.

Taking a glue gun, we attach the CD to the bottom of the plastic box.

We continue to work with a glue gun and fix the emitter frame on the spindle.

We fix the cable on the back of the box with hot glue.

Connecting to a router

Those who have experience can easily solder to the contact pads on the circuit board inside the router.

Otherwise, be careful, thin traces may come off the printed circuit board when heated for a long time with a soldering iron.

You can connect to an already soldered piece of cable from a native antenna via an SMA connector. You shouldn't have any problems purchasing any other N-type RF connector from your local electronics store.

Antenna tests

Tests have shown that an ideal biquad gives a gain of about 11–12 dBi, and this is up to 4 km of directional signal.

The CD antenna gives 8 dBi, since it can pick up a WiFi signal at a distance of 2 km.

Double biquadrate provides 14 dBi - slightly more than 6 km.

The opening angle of antennas with a square emitter is about 60 degrees, which is quite enough for the yard of a private house.

About the range of Wi-Fi antennas

From a native router antenna of 2 dBi, a 2.4 GHz signal of the 802.11n standard can spread over 400 meters within line of sight. Signals of 2.4 GHz, old standards 802.11b, 802.11g, travel worse, having half the range compared to 802.11n.

Considering a WiFi antenna to be an isotropic emitter - an ideal source that distributes electromagnetic energy evenly in all directions, you can be guided by the logarithmic formula for converting dBi to power gain.

Isotropic decibel (dBi) is the antenna gain, determined as the ratio of the amplified electromagnetic signal to its original value multiplied by ten.

AdBi = 10lg(A1/A0)

Conversion of dBi antennas into power gain.

Judging by the table, it is easy to conclude that a directional WiFi transmitter with a maximum permissible power of 20 dBi can distribute a signal over a distance of 25 km in the absence of obstacles.