1900-1909 - Early Experiments


Reginald Fessenden theorizes that an alternator, as developed by Tesla, could generate an electromagnetic wave able to carry voice and music. He uses a spark generator to send the human voice the distance of about one mile.

R. FessendenFessenden


Marconi receives the letter "S" by Morse code (35 K Wav of a spark transmitter) in St. Johns, Newfoundland. John A. Fleming was at the transmitter in England.

Marconi's antenna farm at Poldhu, England.

Karl Ferdinand Braun introduces the use of a crystal detector as part of a wireless receiver.


Reginald Fessenden invents the 'Electrolytic Detector'.
The magnetic detector is invented by Marconi.
Fessenden forms the National Electric Signaling Company.
The DeForest Wireless Telegraph Company is formed.


J.A. Fleming serves as a scientific consultant to the Marconi company, and designs many pieces of early wireless apparatus. He is charged to develop a new detector for wireless signals.
Fessenden commissions GE to develop a high frequency alternator. E.F.W. Alexanderson is put on the project.
John Ambrose Fleming invents the first tube, the "Fleming Valve", or as he called it..an Oscillation Valve.

J.A. Fleming Fleming

His valve is a two element rectifier, made by inserting a metal plate in one of Edison's electric light bulbs.
The Fleming Valve

Fessenden invents 'Heterodyne reception'.
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