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experimental radio wave detector

experimental radio wave detector

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Description
This is the main section of Edwin Howard Armstrong's first regenerative radio circuit, constructed in late 1912 while he was a student at Columbia University. On top is a vacuum tube called an "Audion" made by Lee DeForest. Armstrong's research into the Audion's electrical properties led him to a fundamental discovery. He could wire the tube in such a way as to feed the weak received signal back into the circuit. This "regeneration" of the signal resulted in receivers that could detect distant signals and then amplify them so that they could be heard without headphones.
The invention of radio first involved the transmission and receipt of telegraph dots and dashes rather than voice, hence the term “wireless telegraphy.” The signals tended to be weak and required the operator to wear headphones to hear the signal. Edwin H. Armstrong invented a circuit that allowed people to hear distant radio transmissions without headphones. He built this device around a commercially-available DeForest “Audion” tube in 1913, while a student at Columbia University. The circuit also increased the sensitivity of the receiver and Armstrong received signals from Clifden, Ireland, San Francisco and Hawaii.
Object Name
Radio Wave Detector
radio receiver
Date made
1912
associated date
1912
associated user
unknown
associated person
Armstrong, Edwin Howard
maker
Armstrong, Edwin Howard
Measurements
overall: 17 in x 8 1/2 in x 8 1/2 in; 43.18 cm x 21.59 cm x 21.59 cm
ID Number
EM.314503.07
catalog number
314503.07
accession number
202631
Credit Line
from Marion Armstrong
See more items in
Work and Industry: Electricity
Communications
Exhibition
Inventing In America
Exhibition Location
National Museum of American History
Data Source
National Museum of American History
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