Radio waves permeate our bodies and every millimeter of space around us. Without them, it is impossible to imagine the life of a modern person. For the sake of waves, they have penetrated every area of our lives. For over 100 years they have been part of our life and it is impossible to imagine the existence of a person without them.
What it is?
A radio wave is an electromagnetic radiation that propagates in space at a particular frequency . The word "radio" comes from the Latin - ray. One of the characteristics of radio waves is the frequency of oscillations, which is measured in Hertz . So it is named after the German scientist, physicist Heinrich Hertz. He received electromagnetic waves and investigated their properties. Oscillations of a wave and its frequency are connected with each other. The higher the latter , the shorter the fluctuations.
History
There is a theory that radio waves arose at the time of the big bang. And although there have always been magnetic waves, humanity has discovered them for itself relatively recently. In 1868, the Scot James Maxwell described them in his work. Then the German physicist Heinrich Hertz proved in theory their existence. This happened in 1887. Since then, interest in magnetic waves has not dwindled . Radio wave research is conducted at many of the world's leading institutes.
The scope of radio waves is extensive - it includes radio and radar, television, telescopes, radars, microwave ovens and all kinds of wireless communications. They are widely used in cosmetology. Internet, television and telephony are all modern communications, impossible without magnetic waves.
Expanded use of radio waves
It is thanks to the study of this phenomenon that we can send information over distances . Radio waves are formed when a high-frequency electric current passes through a conductor. Many scientists write to themselves the merit of the invention of radio . And in almost every country there is such a genius to whom we owe this unique invention. In our country, it is believed that one of the inventors was Alexander Stepanovich Popov.
The invention of the radio began with the device of the radio conductor Edward Branly in 1890. This French scientist created his own device based on the idea of Heinrich Hertz, which concluded that when an electromagnetic wave hits a radio device, a spark arises. The Branly device was used to receive the signal. The first to test this device for 40 meters was the Englishman Oliver Lodge in 1894. Alexander Popov perfected the Lodge Lodge. It happened in 1895.
TV
The use of radio waves in television has the same principle. The towers amplify and transmit the signal to the televisions, and they already convert them into an image. Application for the sake of waves in a well connected one also looks the same. Only a denser network of retro- towers is required . These towers are base stations that transmit and receive signals from the subscriber.
Now widespread Wi-Fi technology, which was developed in 1991. Her work became possible after studying the properties of radio waves and their application has expanded significantly .
It is radar that gives an idea of what is happening on earth, in the sky and in the sea, and in space. The principle of operation is simple - the radio wave transmitted by the antenna is reflected from the obstacle and comes back with a signal. The computer processes it and provides data on the size of the object, speed of movement and direction.
Radars since 1950 They are also used on roads to control the speed of cars. This was due to the growing number of cars on the roads and the necessary control over them . Radar is a device for remote sensing the speed of a moving car. The police appreciated the convenience of using this device and after a few years the radars were on all the roads of the world. Each year, these devices have been modified, improved, and today they have a huge number of species. They are divided into two groups: laser and "Doppler".
Radio wave properties
Radio waves have interesting features:
- If a radio wave propagates in a medium other than air, it absorbs energy;
- the wave path is bent if it is in an inhomogeneous medium and is called refraction of the radio wave;
- in a homogeneous sphere, radio waves propagate in a straight line with a speed depending on the parameters of the medium, and are accompanied by a decrease in the energy flux density with increasing distance;
- when radio waves pass from one medium to another, they are reflected and refracted;
- q the diffraction is the property of a radio wave to go around an obstacle that meets in their path, but there is one necessary condition - the magnitude of the obstacle should be comparable with the wavelength s .
Types of waves
Radio waves are divided into three categories: short , medium and long . The first include waves with a length of 10 to 10 0 m, which allows you to create directional antennas. They can be terrestrial and ionospheric. The use of short radio waves was found in communications and broadcasting and over long distances.
The length of medium waves usually varies from 100 to 1000 m. The frequencies characteristic of them are 526-1606 kHz. The use of medium radio waves is implemented in many broadcasting channels in Russia.
A long wave is a wave from 1000 to 10 000 m. That, which is higher than these indicators, is called extra-long waves. These waves have low absorption properties when passing through land and sea. Therefore, the main application of long radio waves is in underwater and underground communications. Their special property is resistance to electric current strength.
Conclusion
Finally, it is worth noting that the study of radio waves continues to this day. And, perhaps, it brought many more surprises to people.