Radio waves permeate the space around us. We are all used to wireless technologies, especially Wi-Fi, but not everyone is satisfied with the coverage of home routers. Walls, trees and other obstacles weaken the signal. If the connection quality is quite suitable for an apartment, then for a suburban area of several acres, the power of standard router models is clearly not enough. Not far from home, for example in a garage, I would also like to use the home Internet without laying additional cables or installing powerful equipment. But you never know where you may need to amplify the radio signal! In any case, the use of an antenna will be the simplest and most profitable option.
Use the experience of radio engineering
A simple piece of wire attached to an antenna can certainly improve the signal, but it often won't work. And all because of the properties of radio waves. The TV model will also not give any results for Wi-Fi, since it is designed to work with TV broadcast frequencies. To create the right antenna, you need to know the wavelength of the signal whose amplification is planned. The shape of the device should be borrowed from radio amateurs. For example, the biquadrat antenna has long established itself as an easy-to-manufacture and reliable signal amplification device. These compact devices provide decentgain from 11 dBi and higher, while the devices built into the router with a power do not exceed 5 dBi.
For people who are extremely far from the electromagnetic part of physics, these indicators can be deciphered as an increase in Wi-Fi connection speed by several times, as well as an increase in connection distance. The biquadrat antenna is directional, covering a sector of 40-50 ° in front of it, which is quite suitable for connecting a building remote from the main dwelling, as well as for creating a local wireless network between fixed stations. Various craftsmen note a stable signal at a distance of 400 to 2500 m, but this is unlikely to be needed, a few tens of meters are enough.
To the store with money or with a soldering iron in hand?
It's always easier to buy a ready-made factory product, but the price of such a device is commensurate with the cost of a new router, and the execution is not always reliable. Inexpensive models from the friendly East are rather fragile, and the contacts and connections in them are far from perfect. Where can I get a good biquadrat device? A do-it-yourself WiFi antenna can be assembled by any radio amateur. For this you will need a soldering iron. If you are familiar with this tool, then the instructions will tell you what and how to do.
Bikvadrat - an antenna consisting of two squares made of wire or other electrically conductive material. They are located in the same plane and are connected in a certain way. This circuit is the main working part of the antenna, a vibrator designed to receive and transmit radio waves. It is best to make such an antenna element from a piece of single-core power copper wire with a cross section of at least 2 mm2.
The thickness of the copper wire depends rather on the selected antenna size, number of mounts and conditions of use. This only affects the strength of the structure, and not the quality of the signal, so it is better to select based on the planned dimensions and the availability of material. The simplest homemade biquad antenna is assembled only from a circuit connected to a coaxial cable, as shown in the figure above.
Additional materials and tools
Of course, additional parts will be required to improve the quality of the antenna. A plate made of any electrically conductive material is suitable as a reflector; only wear resistance and strength are required. Even a CD or aluminum foil used in cooking for baking will do. The main thing is to fix it on a flat, solid base made of wood or plastic, where the rest of the antenna parts will be installed. Additionally, you will need dielectric fasteners to firmly fix the antenna relative to the reflector, as well as a 50 ohm coaxial cable.
A special plug will allow you to connect the device to the router, which you will have to purchase in the store. If the router does not have connectors, like most inexpensive models, you will have to disassemble it and solder the cable directly to the board. Remember, such actions with the router will deprive it ofwarranties, and you will be solely responsible for such actions. The rest of the materials can be picked up locally from what is found in the pantry of the home master.
As is clear from the above, a soldering iron, some solder and flux are a must-have tool. A ruler with millimeter divisions will allow you to maintain the exact dimensions of the product, and pliers or pliers will be required to accurately bend the wire into a contour. A knife and side cutters (nippers) will be needed to work with the cable, and when drilling holes, you will need a drill or a screwdriver and a drill.
Tips & Safety
Beginners may find it difficult to solder, but remember that mastery comes with time. It is necessary to carry out all work with a heated soldering iron slowly, observing the precautions and all the necessary steps so as not to burn yourself and make a strong connection. Before using an electrical appliance, it is imperative to check the integrity of the case, cable and plug.
Protect the work area of the table from possible damage by molten solder or hot flux drops by covering it with a wooden shield or special refractory material. Do not leave a heated soldering iron unattended even after turning it off. A hot appliance can ignite surfaces and objects made of flammable materials. For those who hold a soldering iron in their hands for the first time, it is recommended to make several connections on the remnants of the material or pieces of similar wire in order to fillhand.
Some formulas
Before starting work, let's make a small calculation of the biquadrat antenna. The range of most Wi-Fi routers, according to the IEEE 802.11n standard, is 2.4 GHz. Using the formula for the ratio of wavelength, speed and frequency, you need to divide the speed of light by the frequency. 0, 1249 m or 125 mm is approximately the size we need, which means that the side of the squares of the antenna must be a multiple of this particular distance in order to work in the desired range. For the small antenna described here, a distance of 32 mm was chosen. Of course, a multiple increase in this distance will lead to an improvement in the signal over a larger coverage area.
Optimal reflector
There were many ideas on what to use as a reflector, but for such dimensions, an empty circuit board measuring 10 x 10 cm was optimal. First, it simplified the connection of the coaxial cable braid to the reflector. With ordinary solder, the cable is tightly installed in the right place. Secondly, the rigidity of the textolite fully satisfies the dimensions of the product and makes it possible to refuse additional fasteners. Problems when using a model of this size may arise in case of inaccurate dimensions, so all actions are performed using a millimeter ruler.
Progress of work
Homemade bi-square wifi antenna is pretty easy to make. In the center of the circuit board or other suitable sheet of metal, a hole should be drilled according to the diameter of the coaxial cable or slightly larger. cable needstrip from the top insulation by 2.5 cm and carefully insert into the hole in the board. The upper shielding braid or cable casing is soldered around the entire circumference. The cable must sit tightly in the gearbox board, because apart from it, this model does not provide mounts for the antenna. You can additionally use a metal tube to strengthen the structure, this is especially true if you decide to increase the size of the antenna.
Antenna location
A bi-square vibrator will require 256mm of copper wire. You can mark the folds every 32 mm with a marker and take a little more wire to cut off the excess at the end. And you can bend a precisely measured piece of wire each time exactly in the middle. Its ends must be carefully soldered and removed from the opposite corner by 2 mm, you can also leave the connection of the ends to the next stage.
The last step is to solder the connections between the bi-square vibrator and the cable. Keep track of its location relative to the reflector, the distance between them should remain about 15 mm over the entire plane. Such a gap is measured by various testers empirically. If you have the equipment, you can personally search for the optimal distance with the best standing wave ratio for a particular model.
There is no limit to perfection
Point your antenna towards the working area and connect to the router using a special plug, or install with a soldering iron directly on the working board. Increasing the range of the Wi-Fi signal will not force itselfwait. What else can be done to increase the power of the antenna, besides increasing the size? Those who have already built something similar may be interested in a double or triple biquad antenna. With their own hands, craftsmen achieve signal amplification by 2 and 4 dBi more, and this is a tangible improvement.
This is done by increasing the number of squares and, accordingly, the area of the reflector (metal gearbox). Craftsmen also create arc-shaped or circular antennas based on a biquadrate, the main rule in the manufacture of which is the strict observance of a distance of 15 mm from the reflector over the entire area of \u200b\u200bthe device. It is also worth mentioning that wire crossings must be insulated so that there are no conductor connections.
The places where the biquadrat antenna is installed can be very diverse. Most often, such products are mounted on windows or outside the building. For weatherproofing a small model like the one above, a plastic container works great. The signal gain achieved by the bi-quad antenna matches and sometimes exceeds factory models.
