If during a trip to Russia a person will listen to a certain radio station on the radio, he will notice that it broadcasts in different cities on different waves. This begs the logical question: why does the radio station not use one frequency to transmit a signal throughout the country?
Radio development
The physicist Hans Oersted experimentally established in 1820 that electricity can affect magnetic objects. He placed a compass near the volt pole, after which he closed the electric circuit. While heating the wire, the compass needle deflected. Thus, the scientist proved the existence of electromagnetic waves, with which you can transmit a signal at a distance.
The discovery of Oersted has received increased attention in the scientific community. In 1895, Alexander Popov invented the first radio receiver capable of receiving signals from a distance. However, Guglielmo Marconi was the first to patent this invention, a year later. The Italian created a receiver working on the same principle, and registered it in his name. It is worth noting that Marconi invented the device, not knowing anything about the works of Popov. Both scientists created their own versions of the radio independently of each other (this is not an isolated case in history - the invention of the telephone is a confirmation of this). And people are still arguing over who to consider as the full inventor of radio.
The field of radio quickly began to develop in the world.Already in 1906, there was a successful transmission of a message between two radio stations in Morse code, which allowed people to communicate at a distance without letters. At the end of that year, an audio signal was transmitted on the radio.
For three years, physicists and inventors of that time seriously improved the mechanism of radio receivers, increasing their power. In 1909, the first radio station in the world, San Jose Calling, based in California, began its work.
Interesting fact: at that time the expression “broadcast” appeared, it was borrowed from farmers, who called the process of scattering seeds into beds.
In the 1920s, the amplitude signal transmission method (AM) was invented, allowing broadcasting over long distances. And in 1941, people discovered the method of frequency modulation (FM). This method allowed to transmit signals at a specific frequency. This allowed each station to use an individual frequency and not interfere with the rest.
Not so long ago, radio stations in Europe began to experiment with the digital broadcasting method, but at the moment it has not received widespread use.
Why is a radio station broadcasting at different frequencies in different cities?
In Russia, most stations use frequency modulation (FM) for signal transmission. Each signal requires an individual frequency, which cannot be occupied by the rest, so as not to create interference on the air. All radio frequencies are state owned and used for their respective needs. Distributed by competition.
Since broadcasting technology is now publicly available, anyone can organize a station and conduct broadcasts at a certain distance (by issuing a license). Because of this, there are thousands of radio stations in the country, and a separate frequency is allocated for each.
In order to receive its own wave for broadcasting, the station registers in its region. Moreover, in Russia there are both local radio channels that transmit a signal only within a city or region, and large ones with a wide broadcasting network.
It is because of the large number of local stations that large ones in different cities transmit a signal at different frequencies. When a large radio station decides to start broadcasting in another city, it may well turn out that a local station is already operating on its usual waves. Because of this, you have to take a different frequency.
Radio stations broadcast on different frequencies in different cities, since this frequency can already be occupied by the local station. Because of this, a different frequency is chosen for the esters.
