forms of information transmission today are based on radio i.e. the use
of electromagnetic waves. The preceding history since the middle of 18th
century comprises the observations by a great number of physicists investigating
the phenomena of electricity and magnetism and their search for a fitting
Based on this work Maxwell in 1864 postulated the relation between electric
and magnetic field expressed in a new mathematical form. He introduced the
subsequently much debated concept of "displacement current" for
a non closed circuit and derived a wave equation in free space with light-like
properties. Hertz proved from 1888 the validity of Maxwell's theory and
discovered the advantage of tuning reception to transmission frequency.
Marconi was the experimenter who foresaw the practical application for message transmission, in particular for ships at sea. He started experiments from 1895 onwards over increasing distances until in 1901 he successfully bridged the Atlantic from England. It is astonishing to realise this happened barely one century ago.
Fleming, working for Marconi reported in 1904 the use of an incandescent lamp with an added electrode as a detection device, replacing the clumsy "cohearer". Two years later de Forest added another electrode to Fleming's diode thus giving birth to the triode.
Further developments led to the situation in 1927 when the Measurements Building was founded.
Marconi's receiving station at New Foundland (antenna wire attached to a kite) source: Nature 1902
(full size 49 KB)