The Radio (Group 1)

Guglielmo Marconi

Radio is an invent for transmission and detection of communication signals based in electromagnetic waves. These waves travel through the air from different ways, like through a communication satellite. Moreover, Guglielmo Marconi was the inventor of this machine.

Guglielmo Marconi (1874-1937) born in Bologna, Italy and he was a good inventor of the Wireless telegraph. He worked on the development of shortwave wireless communication and the modern long-distance radio.

This inventor was educated in Italy and he studied in the technical school in Leghorn, where, in studying physics, he had the opportunity for investigating electromagnetic wave  technique, following the earlier mathematical work of James Clerk Maxwell and the experiments of Heinrich Hertz, who first produced and transmitted radio waves, and Sir Oliver Lodge, who conducted research on lightning and electricity. For this reason, Marconi repeated Hertz’s experiments and succeeded in getting secondary sparks over a distance of 30 feet (9 metres). But he attached one side of the primary spark gap to an elevated wire (an antenna) and the other to Earth, with a similar arrangement for the secondary gap at the receiving point. Finally the distance between transmitter and receiver was gradually increased first to 275 metres, then to three kilometres, then across the English Channel, and at the end, to 3,200 kilometres.

The radio wave is made up of electric and magnetic fields vobrating mutually at right angles to each other in space. Both reach their máxima and minima together and both go through zero together.As the distance from the source of energy increases, the area over which the elctric and magnetic energy is spread is increased, so the available energy per unit area is decreased. So, radio signal intensity, like light intensity, decreases as the distance from the source increases.

The antenna can be designed to concéntrate the radio energy into a beam likea searchlight and so increase its effectiveness in a given direction.

Any sudden discharge of electrical energy, like that of lightning, produces transient radio-frequency waves, which are picked up by antennas. However, switching of high-voltage power lines can produce simiar effects; the lines help to carry the noise-producing signals over long distances.

Many countries have legislation requiring the suppression of man-made noise by means of filters that reduce the amount of radio-frequency energy released at the source. Metallic shielding of leads to and from the noise-reducing devices at the input to radio receivers. But noise can also be caused by irregularities in the flow of electrons in metals, transistors and electron tubes.

When he verified his invention, he changed the world forever!

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Gugliemo Marconi (Additional information)