Early history of radio

1. In 1865 a Scottish physicist, Maxwell, demonstrated mathematically the theory of electromagnetic energy. This was confirmed in 1888 when Heinrich Hertz, a German, caused an electrical discharge between two metal balls spaced very close together. Hertz's achievement was to project the charge from the space between the balls across a distance of some feet to detection apparatus consisting of a wire loop with a similar gap. Hertz had demonstrated the ability to convert electricity into another form, electromagnetic energy, which could be conducted over distance without wires. This energy came to be known as radio waves, Hertzian waves or simply wireless¹. Many others contributed to the improvement of transmission and reception devices², including New Zealander Ernest Rutherford who, in 1894, developed a more sensitive receiver known as a magnetic detector for radio waves.
2. It was left to a 21 year old Italian - Irishman Guglielmo Marconi to realise the communication possibilities of artificially generated radio wave energy³. In 1895 he experimented on the family farm near Bologna with a home - made transmitter and receiver and, most importantly, added a telegraph morse key. With this primitive equipment he managed to send the letter 'S' in morse over a distance of 3 kilometres. The Italian Minister for Post and Telegraph declared that the new technology had no potential for communication purposes so Marconi took his ideas and equipment to England where the British Government backed his work. In 1899 he sent a message across the English Channel, and by 1901 he had spanned the Atlantic. The technology was primitive and the concept of frequency management as a means of enabling simultaneous radiocommunications was still largely unrealised.

Footnotes

¹ Radio waves were also known as airwaves because its was originally thought that air molecules conducted radio energy, or in other words radio waves could not propagate in a vacuum. Although this was proved incorrect, and satellite and spacecraft radicommunication today confirms it, the term remains in common use.

² Righi (Italian), Lodge (English), Branly (French) and Popov (Russian)

³ Naturally ocurring radio wave energy, such as that emitted by stars and other objects in the universe, has no known utility for communication purposes.