The History of Radio

Ham Radio has a long tradition in STEM

We go back to the 1590s ...

• 1590s William Gilbert (English) first formal experiments in electricity and magnetism.
• 1746 Jean le Rond d’Alembert (French) formulated the one dimensional wave equation describing the motion of a vibrating string
• 1750 Benjamin Franklin (American) developed the law of conservation of charges
• 1755 Charles Augustin de Coulomb (French) invented a very sensitive balance relating mechanical forces due to magnetic and electric fields
• 1780 Karl Gauss (German) developed divergence theorem to be used in Maxwell’s equations
• 1800 Alessandro Volta (Italian) invented the voltaic cell and the battery
• 1819 Hans Oersted (Danish) observed that an electric current flowing on a wire deflected a compass
• 1820 Andre Ampere (French) invented the solenoid and thus produced significantly higher magnetic force from an electrical current.
• 1821 Georg Ohm (German) derived his famous law (Ohm's Law) relating voltage, current and resistance.
• 1831 Michael Faraday (English) discovered and quantified the phenomena of a changing magnetic field producing an electrical current and an electrical current producing a magnetic field
• 1831 Joseph Henry (America) independently observed the same phenomena as Faraday
• 1860s/70s James Maxwell (Scottish) combined the equations of Faraday, Gauss, and Ampere into one set of relationships that precisely define the behaviour of electromagnetism and (more importantly for us) the behaviour of electromagnetic waves. He also postulated that light is an electromagnetic wave
• 1886 Heinrich Hertz (German) built the first complete radio system consisting of a spark gap transmitter, transmitter antenna, receiver antenna, and a spark gap receiver.
• 1887 Albert Michelson and Edward Morley (American) proved that space was not filled with an “invisible ether” which along with other scientific knowledge and Maxwell’s equations led to Einstein’s Theory of Relativity
• 1895 Gugliemo Marconi (Italian) invented practical radio. Hertz was a physicist interested in science, Marconi was an engineer who took that knowledge and built something useful
• 1901 Marconi sends messages between Newfoundland and England

Modern "wireless" is born ...

This timeline is courtesy of Antenna Physics: An Introduction by R Zavrel, Jr. W7SX

Since the first transatlantic message 122 years ago radio has been refined immensely. From a room full of equipment radio transceivers are now, well the size of your cellphone. We started out using on off keying (Morse Code), then voice transmissions came along followed by Single Side Band voice operations, video, stereophonic sound and then various modes of digitally encoded voice, video and data.