Why the 3G / 4G technology is alive
The standard of wireless networks is still powerless to oust mobile communication technology, is simply explained: the range is relatively small. Certain other features are noticed, of course - the difficulties of identification, the large amount of energy consumed, the key moment in the distance. Consider whether it is possible to make a directional Wi-Fi antenna yourself.
Frightening posing a question. It's simple, take the trouble to master a couple of terms. Popov, inventing the radio, knew little about how electromagnetic waves propagate. There simply were two wire antennas - the first one radiated, the second one received. It gradually became clear: the nature of wave propagation by the atmosphere was determined in addition to the frequency( wavelength) of weather conditions.
Immediately the optimal ranges were taken by the state, providing military needs, communication organizations. Remains given to broadcasting, radio amateurs.
In addition to the conditions of energy distribution, antennas play an important role in the organization of a stable channel. If nothing can be done with the wavelength ranges, they are set a priori, it is possible to conduct experiments with antennas.
Antennas used by Popov, omnidirectional. The power of the signal is uniform on all sides of the world. Quickly, engineers discovered this fact, began to look for ways to correct the deficiency.
Solutions found were many. In the simplest case, the emitter is placed at the focal point of the hyperbolic plate. It turns out satellite TV antenna. The effect is similar to the optical one: the rays falling at a right angle on the opening of the trimmed hyperboloid are collected as a focal point. The plate is called a reflector - from Latin - a reflector. Transmitting, receiving antennas placed in focus work more efficiently than an omni-directional Wi-Fi antenna.
Direction pattern, gain
A person far from engineering calculations asks: the rays are collected in focus, multiplying the power of the incoming signal many times, what are the transmitters here? Antenna reception and transmission properties are identical. Characterized by a radiation pattern. The curve, round or built in a rectangular coordinate system, shows how much power is radiated in a given direction.
Popov's antennas had a diagram close to a circular shape. Otherwise, a directional Wi-Fi antenna operates: a long peak is formed ahead. The height is so huge, you have to express in decibels - relative units, otherwise you will have to draw a thin needle in the middle, even zero horizontals on the sides. Beloved
The last term left to know is antenna gain. The ratio of the peak power of the main direction to the power radiated in similar conditions by an omnidirectional antenna. The parameter is in the hundreds of units, expressed in decibels( 20 dB).
It is easy to understand why the directional Wi-Fi antenna is so effective - it amplifies the signal many times. The self-made models, discussed below, are devoid of such grandiose indicators, the 6 dB gains bring more than 2 dB of a standard antenna coming with a router kit.
The simplest versions of self-made Wi-Fi antennas
The SLTV master class with the help of a leading blonde told about two well-known ways to make a router antenna. The main idea mixed up is that the pin sticking out of a small box is equipped with a reflector. There is no need to talk about placing the emitter into focus, no zero effect is expected.
The simplest way is to equip the antenna with a laser disk with the shiny side out. The mechanics are simple: the aluminum layer of the printed, recorded product perfectly reflects any wavelengths, within reasonable limits.
The directional pattern of the pin will change dramatically - on the contrary, perpendicular to the disk, a pronounced maximum will appear. You have to place the spire horizontally, apex to consumers, or most of the energy goes up. The blonde, smiling sweetly, said: in addition to this method, there is a more advanced way to make a directional antenna with your own hands.
You need an empty, dried beer can, another one is similar. The bottom is cut off, the neck is separated by the perimeter, you need to leave a narrow isthmus a couple of centimeters wide.
The sidewall is dissected straight along, diametrically opposite the isthmus. The walls are leveled. Now, through an egg-shaped hole, from where the opener is torn off, the reflector is put on the antenna.
The rounded wall resembles a paraboloid plate with trimmed edges. Advantage of the solution: you can rotate the reflector in a circle, adjusting the right direction.
Gain will have to adjust the skillful hands, sensitively choosing the position of the reflector. Now the Wi-Fi antenna is directional.
In addition to the spire of the router, similar actions are allowed with a low-power Wi-Fi modem( flash drive).You will need a USB extension cable. Strengthening the knowledge gained( see the first two methods), we will manufacture a reflector, plus a protective cover from:
- laser disk boxes with one disc at the bottom;
- flat metal screen with folding edges and a small plastic can;
- hemisphere / truncated hyperboloid-shaped large wire sieve;
- is a self-made braided thin cable construction with a metal rod frame.
The modem flash drive is placed as close as possible to the focus, the cord through the slot in the center of the reflector goes to the personal computer.
Reception will undoubtedly improve when there is a Wi-Fi antenna with your own hands. The undoubted advantage of the design is the possibility of arbitrary orientation of the main beam of the radiation pattern. Usually there is one remote source / receiver signal, there should be deployed a modem with a reflector.
Beer banks are used to help microwave spectrum designers. They remind the waveguides, inside covered with aluminum. Not surprisingly, hams often try to adapt the tin to the needs of catching broadcasting.
This case is typical. Children's shops of the USSR filled with. .. a sled. It was a turn until local engineers realized that the products lying on the shelves are parabolic antennas, the clerks returned the items rejected by military acceptance to the sellers. By the end of the day, the sled was bought out.
The retreat has the sole purpose of showing: a Wi-Fi antenna is easily made from scrap materials. The rectangular waveguide is impossible to make, the round is made by the brewery.
To make the bank a decent 2.4 GHz reflector, take care to carefully cut the bottom. The emitter will be a quarter-wave vibrator, formed by a piece of thin( 1.5 mm) wire about 5 cm long. 1.5 cm will be recessed by the n-connector, 30 mm should protrude above the inner wall.
The slot hole is cut in the bottom of the side wall at a distance from the bottom, defined by the can diameter. For 90 mm indentation will be 51 mm, for 80 - 70 mm. We'll have to pick up the distance by trial, spoiling a lot of great beer cans.
Further actions are very simple - the vibrator is strengthened perpendicular to the inner wall, speaking 30 mm.30 degree wide pattern. Polarization is important: two banks with emitters directed perpendicular to each other will refuse to work together.
By the way, the 30 mm long wire pin is an omnidirectional Wi-Fi antenna made from the improvised material, designed to master the 2.4 GHz frequency. Handy materials - great! It remains to supplement the pin with counterweights, which play the role of a receiving earth.
The model refuses to catch frequencies of 900 MHz, 5 GHz, besides - when choosing a can, give preference to containers with a diameter of 7–10 cm.
Attach the assembled
device In previous cases, it is simple. They took a Wi-Fi modem, a connected antenna, surrounded by a reflector. A beer can with a quarter-wave vibrator is slightly different in terms of docking: by opening the flash drive-modem, inside you will find contacts to connect the tin. There are antenna slots in routers where beer production will fit perfectly.
Naturally aluminum, copper product can replace the capacity of hot drink. Dimensions are selected similar. Good luck with your design.