History of Radio

  • Luigi Galvina

    Luigi Galvina
    Luigi Galvani notices a spark generated near by causes a convulsion in a frog's leg being touched by a scalpel. In a different experiment, he notices contractions in frogs legs caused by lightning.
  • Hans Christian Ørsted

    discovers the relationship between electricity and magnetism in a very simple experiment. He demonstrates that a wire carrying a current was able to deflect a magnetized compass needle.
  • Michael Faraday

    Michael Faraday
    begins a series of experiments in which he discovers electromagnetic induction. The relation was mathematically modeled by Faraday's law, which subsequently becomes one of the four Maxwell equations. Faraday proposes that electromagnetic forces extended into the empty space around the conductor, but does not complete his work involving that proposal.
  • Peter Samuel

    observes the permanent increase of the electrical conductivity of a mixture of loose metal filings in a glass tube with two metal plugs in it resulting from the passage of a discharge current of a Leyden jar through it. This is an early example of the coherer effect.
  • Edwin Houston

    while setting up a large sparking Ruhmkorff coil to be used in a demonstration, notices he can draw sparks from metal objects throughout the room. He attributes this to induction.
  • Thomas Edison

    notices an electromagnet producing unusual sparks. He finds this strange sparking could be conducted 25 miles along telegraph wires and be detected a few feet from the wire. To prove it was not electromagnetic induction he set up an experiment where he shows sparks in a spark detector but no effect in a gold-leaf electroscope and a galvanometer along the same line. On 28 November 1875 he announces to the press what he termes a new "etheric force".
  • Dvaid E. Hughes

    Dvaid E. Hughes
    notices that sparks generated by a induction balance causes noise in an improved telephone microphone he was developing. He rigs up a portable version of his receiver and, carrying it down a street, finds the sparking can be detected at some distance.
  • Hermann Hemholtz

    proposes the "Berlin Prize" for anyone who could experimentally prove a key aspect of Maxwell's electromagnetic theory thinking his star student, Heinrich Rudolf Hertz, could win the prize. Hertz declines working on the prize, seeing no way to produce a test apparatus.
  • Nathan Stubblefeild

    Nathan Stubblefeild
    farmer Nathan Stubblefield conducts wireless transmissions some claim to be radio, but his devices seem to have worked by induction transmission rather than radio transmission.
  • Oliver Lodge

    Oliver Lodge
    conducts experiments that seem to show electromagnetic waves traveling along wires. He took this as a way to prove Maxwell's electromagnetic theory but learns of Hertz' published proofs at the same time.
  • Federick Thomas Trouton

    suggests using a fast rotating alternator as a wireless transmitter and suggest the new "Hertzian waves" could be used to replace light houses with "electric houses" that would operate in fog.
  • Joseph Henry

    publishes his experimental results showing the oscillatory nature of the discharge in leyden jars and describes how a generated spark could magnetize a needle surrounded by a coil up to 220 feet away. He also describes how a lightning strike 8 miles away magnetized a needle surrounded by a coil, an effect that was most probably caused by radio waves. He considered both of these effects to be due to electromagnetic induction at the time.