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. Radio waves have penetrated every area of our lives. For more than 100 years, they have been a part of our lives and it is impossible to imagine the existence of a person without them.
What is this?
Radio wave - electromagnetic radiation that propagates in space with a special frequency. The word "radio" comes from the Latin - ray. One of the characteristics of radio waves is the oscillation frequency, which is measured in Hertz. So it is named after the German scientist, physicist Heinrich Hertz. He received electromagnetic waves and investigated their properties. Wave oscillations and its frequency are related to each other. The higher the latter, the shorter the oscillations.
History
There is a theory that radio waves originated at the moment of the big bang. And although magnetic waves have always existed, humanity has discovered them relatively recently. In 1868, the Scotsman 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 dried up. Radio waves are being researched at many of the world's leading institutes.
The areas of application of radio waves are extensive - these are radio, and radar, television, telescopes, radars, microwave ovens and all kinds of wireless communications. They are widely used in cosmetology. The Internet, television and telephony - all modern communications are impossible without magnetic waves.
Expanded applications of radio waves
It is through the study of this phenomenon that we can send information over distances. Radio waves are generated when a high-frequency electric current passes through a conductor. Many scientists attribute the merit of the invention of radio to themselves. And in almost every country there is such a genius to whom we owe this unique invention. In our country, it is believed that Alexander Stepanovich Popov was one of the inventors.
The invention of the radio began with Edward Branly's radio conductor in 1890. This French scientist created his device based on the idea of Heinrich Hertz, which was that when an electromagnetic wave hits a radio device, a spark is created. The Branly instrument was used to receive the signal. The first to test this device at 40 meters was the Englishman Oliver Lodge in 1894. Alexander Popov improved Lodge's receiver. It happened in 1895.
Television
The use of radio waves in television has the same principle. TV towers amplify and transmit the signal to TVs, and they already convert them into an image. The use of radio waves in cellular communication looks the same. Only a denser network of retroseror towers is required. Thesetowers are base stations that transmit and receive signals from the subscriber.
Wi-Fi technology, which was developed in 1991, is now widespread. 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 returned back as a signal. The computer processes it and gives data about the size of the object, the speed of movement and the direction.
Radars have also been used on roads since 1950 to monitor the speed of vehicles. This was due to the growing number of cars on the roads and the necessary control over them. Radar is a device for remotely determining the speed of a moving vehicle. The police appreciated the convenience of using this device and a few years later the radars were on all the roads of the world. Every year these devices have been modified, improved and today there are a huge number of types. They are divided into two groups: laser and "Doppler".
Properties of radio waves
Radio waves have interesting features:
- if a radio wave propagates in a medium other than air, then it absorbs energy;
- wave trajectory is curved if it is in an inhomogeneous medium and is called refractionradio waves;
- 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 travel from one medium to another, they are reflected and refracted;
- diffraction is the property of a radio wave to go around an obstacle that is encountered in their path, but there is one necessary condition here - the magnitude of the obstacle must be commensurate with the wavelength.
Types of waves
Radio waves are divided into three categories: short, medium and long. The first include waves with a length of 10 to 100 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 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.
Long is a wave from 1000 to 10,000 m. Anything above these figures is called ultra-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.
Conclusion
Finally, it is worth noting that the study of radio waves continues to this day. And, perhaps, it will bring many more surprises to people.
