History of radio

By Simon Griffith

  • Luigi Galvani

    Luigi Galvani
    Luigi notices a spark generated near by causes a convulsion in a frogs leg being touched by a scalpel.

  • Hans Christian

    Hans Christian
    the relationship between electrisity and magnetism in a very simple experiment.

  • telegraph

    telegraph
    While experimenting with an acoustic telegraph, Thomas Edison notices an electromagnet producing unusual sparks.

  • Temistocle

    Temistocle Calzecchi-Onesti at Fermo in Italy discovers that metal filings between two brass plates clump together in reaction to electric sparks occurring at a distance.

  • Amos dolbear

    American physicist Amos Dolbear predicts telegraphing without wires using "A beam of Hertzian rays" in Donahoe's Magazine.

  • Lodge

    Oliver Lodge delivers a memorial lecture on Hertz where he demonstrates the optical properties of "Hertzian waves" (radio), including transmitting them over a short distance, using an improved version of Branly's filing tube, which Lodge has named the "coherer", as a detector.

  • Waves

    Waves
    Marconi pursues the idea of building a wireless telegraphy system using Hertzian waves (radio). This is considered to be the first development of a radio system specifically for communication.

  • Ernest Fisk

    n Australia, Ernest Fisk (later Sir Ernest) of AWA – Amalgamated Wireless (Australasia) conducted an isolated experiment in which music was broadcast.

  • music

    music
    Reginald Fessenden used an Alexanderson alternator and rotary spark-gap transmitter to make the first radio audio broadcast, from Brant Rock, Massachusetts.

  • an electronics instrutor

    Charles David Herrold, an electronics instructor in San Jose, California constructed a broadcasting station. It used spark gap technology, but modulated the carrier frequency with the human voice, and later music.

  • titanic

    titanic
    The RMS Titanic sank. While in distress, it contacted several other ships via wireless. After this, wireless telegraphy using spark-gap transmitters quickly became universal on large ships.

  • Life at sea

    The International Convention for the Safety of Life at Sea was convened and produced a treaty requiring shipboard radio stations to be manned 24 hours a day. A typical high-power spark gap was a rotating commutator with six to twelve contacts per wheel, nine inches to a foot wide, driven by about 2000 volts DC.