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Heaviside, Oliver

theory layer signals earth

(1850–1925) British physicist: developed theoretical basis of cable telegraphy.

Lacking a university education, Heaviside worked initially as a telegraph operator until deafness forced him to stop. Unmarried, he lived with his parents, never obtained an academic position (although he received several honours) and eventually died in poverty.

Working alone, Heaviside developed much of the mathematics behind the theory of telegraphy and electric circuits, formulating the now familiar concepts of impedance, self-inductance and conductance and using complex numbers in the analysis of alternating current networks many years before others did so. He showed how audio signals could be transmitted along cables without distortion and proposed a method of using a single telephone line to carry several conversations simultaneously (multiplexing). Following success in transmitting radio signals across the Atlantic, he suggested, independently of A E Kennelly (1861–1939), that there had to be a reflecting layer in the upper atmosphere, otherwise the curvature of the Earth would prohibit the signals from being received. The existence of the Heaviside layer was demonstrated experimentally over 20 years later by . Also known as the E-region or middle layer of the ionosphere, it usually lies between 90 km and 150 km above the Earth.

Although most of Heaviside’s earlier work was ignored, leading him to become embittered and a recluse, his valuable contributions were later acknowledged and he was elected a Fellow of the Royal Society in 1891. The last, unpublished, volume of his Electromagnetic Theory was torn up by burglars a few days after his death, but is known to have described a unified field theory combining electromagnetism and gravitation.

Hebard, Grace Raymond (1861–1936) - Local History [next] [back] Heaven

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