The structure of a radio station is simple: a microphone, a sound table, a transmitter, an antenna, a receiver and a lot of knowledge of physics are enough to make everything work. Physics is the answer to how to make a sound propagate through electromagnetic waves through the air. Many people pursued this idea in the late 19th century: anyone who could find a way to replace the telegraphs and cables used to send messages would become rich. Today, technology is not only used to transmit music on more than 7,000 official stations in Brazil, but it is also the basis for the operation of various devices,
When it leaves the station, sound propagates like a wave until it reaches the radio1. A radio station’s studio is acoustically insulated, usually with foam, which blocks out external noise. There, the speaker speaks to the microphone, which is a “transducer”: it receives the vibration of the voice in mechanical waves and converts them into electrical current
2. The microphone is connected to a sound board, as well as the CD or MP3 player and the computer where commercials, sound effects and, of course, music are stored. The function of the sound board is to unite these sounds to others, such as the phone calls of the listeners, and to sieve what goes on the air
3. The signal in the form of electrical impulses that comes out of the table is weak, so it passes through an amplifier, which increases the intensity of electrical current through an electronic circuit. This amplification can be hundreds or thousands of times, depending on the area affected
4. At the top of the station is the antenna – there, it is easier to prevent the signal from being interrupted by buildings or geographical accidents. It receives electrical signals and turns them into electromagnetic waves. Each antenna emits two types of signals together: the carrier wave, which carries the radio frequency, and the amplified current, which contains the sound
5. These signals reach the receiver, the radio. When we touch the dial, an internal circuit causes the device’s antenna to oscillate according to each station. The speakers then convert the electrical waves into mechanical vibrations, which are the sound itself
