The First Half Century (1895-1945): Milestones in Radio

Article excerpt

1895

* Aleksandr S. Popov (Russia) invents the lightning-recording antenna. On 7 May he presents the first receiver of electromagnetic waves to the St. Petersburg Physical and Chemical Society.

* Near Bologna (Italy) Guglielmo Marconi carries out the first experimental transmission of wireless signals over a distance of 400, then 2,000 metres.

1896

* 2 June: In England, Marconi files a patent for a system of wireless communication, and later transmits and receives Morse code signals over a 3 km distance.

1897

* Eugene Ducretet (France) experiments with wireless telegraphy.

* Marconi founds the Wireless Telegraph and Signal Company, Ltd., in London.

* Karl Ferdinand Braun (Germany) invents a device which completes "the tuned circuit", matching the wavelength of transmitter and receiver, a procedure discovered by Sir Oliver Lodge (U.K.).

1898

* 5 November: Ducretet describes to the French Academy of Sciences transmissions between the Eiffel Tower and the Pantheon in Paris (4 km).

1899

* A 42-km link is established in France between two cruisers equipped with Ducretet-Popov devices.

* 28 March: Marconi makes a wireless transmission across the English Channel from Dover to Wimereux.

* Popov makes transmissions covering 50 km. from the shore to Russian ships.

1900

* Marconi obtains a patent for a process enabling an operator to select a wavelength. (The first receivers picked up all frequencies at the same time.) February: The first commercial wireless station is set up, on the island of Borkum (Germany).

1901

* 12 December: Marconi makes the first transatlantic wireless transmission, using Morse code, between Poldhu in Cornwall (U.K.) and St. John's, Newfoundland.

1903

* In Germany Siemens and Allgemeine Elektrizitats Gesellschaft create a joint affiliate, Telefunken.

* Valdemar Poulsen (Denmark) invents a means of producing continuous waves by "arc transmission", later used to construct high-frequency alternators for sending continuous radio waves.

* Gustave Ferrie sets up a long-distance telegraph station on the Eiffel Tower.

* The London Times and the New York Times receive information about the Russo-Japanese war via radio.

1904

* First experiments with telegraphic radio links in Spain.

* In France a commercial maritime radio network is set up under the control of the Ministry of Posts and Telegraphs.

* 16 November: John Fleming (U.K.) invents the thermionic two-electrode valve, or diode, making possible sound transmission.

* A radiotelegraphy station is built on the Adriatic coast in the principality of Montenegro.

1905

* In Canada, the Wireless Telegraph Act stipulates that a licence must be obtained for wireless telegraphy.

* First wireless communication in Spain, between El Ferrol del Caudillo and La Coruna.

* Discovery of the properties of galena (lead sulphide) as a detector of radio-electric signals.

1906

* Reginald Fessenden (U.S.A.) constructs a high-frequency alternator and succeeds in transmitting the human voice via radio.

* 25 October: Lee de Forest (U.S.A.) applies for a patent on the triode, a 3-electrode valve that makes possible the detection, transmission and amplification of radio signals.

1908

* 2 April: De Forest experiments with his triode in France by broadcasting from the Eiffel Tower.

1910

* 13 January: A broadcast from the Metropolitan Opera House in New York featuring Enrico Caruso is arranged by Lee de Forest and is heard 20 km away on a ship at sea.

1912

* 15 April: Radio amateurs pick up the SOS sent out by the Titanic.

1913

* Amateurs with galena-crystal radios listen in to the first regular weekly musical programmes broadcast from a wing of the Chateau de Laeken (Belgium). …