An overview of the key milestones in the history of radio technology and its development
Early beginnings – It is impossible to say exactly where the story of radio starts. The early scientists who saw and investigated the effects of electricity and magnetism were crucial to the story. But a number of people also noticed effects that were probably caused by radio waves. Galvani is thought to have witnessed the effects of electromagnetic waves as he was investigating the conduction of electricity. Others too including Henry, Edison and others may also have witnessed effects as well.
Maxwell proves the existence of e/m waves – It was James Clerk Maxwell who first proved the existence of an electromagnetic (e/m) wave. He proved it mathematically, and published his findings in a number of papers. Much of this early work was performed whilst he was at Kings College London. His work was summarised in a book entitled “Treatise on Electricity and Magnetism.” In 1871 Maxwell moved to Cambridge where he became the first director of the Cavendish Research Laboratory.
1887 Hertz discovers radio waves – In a series of experiments started in 1887 Heinrich Hertz proved the physical existence of radio waves that Maxwell had shown to exist mathematically. His transmitter consisted of a simple spark gap across an induction coil with a loop of wire to act as an antenna. The receiver consisted of a smaller gap in a loop the same size as that in the transmitter. In his experiments Hertz also discovered many of their properties. The results of his experiments performed in 1887-8 were published between 1888-90. Whilst other people had seen the effects before, nobody had realised what they were, and Hertz is rightly credited with having discovered radio or Hertzian waves as they were first called.