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RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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December 1937 Radio-Craft[Table of Contents]
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles from Radio-Craft.
Well... it was 50 years ago referenced to the year this story was published in 1937. That makes it 128 years ago referenced to 2015. The story's point is that half a century had passed already since the confirmation of existence of electromagnetic waves as proposed by James Clerk Maxwell. Heinrich Hertz's 'Funken-Induktor' (spark inductor) and his "Knochenhauershen Scheiben" (Karl-Wilhelm Knochenhauer's disk-type capacitors) were key to his ability to generate, transmit, and receive EM energy. The work originated from attempts to prove that light was a form of electromagnetic waves.
BTW: Does anyone know what appending 'shen' to the end of a name means; i.e., 'Knochenhauershen?'
Having demonstrated, in 1887, the existence of the electromagnetic variations (forecast by Maxwell) which we today call radio waves he modestly wrote: "It is not for me to say whether the discovery I have made is truly wonderful, but it makes me very happy to know that other people say so."
The turning of the third-quarter of the last century found scientists and other learned people preoccupied with the bewildering question "What is Light?" Various theories had been expounded without having satisfactory basis in fact or without having sufficient proof. At last in 1875 Clerk Maxwell asserted that light was the result of oscillations produced by an electromagnetic field existing somewhere in space and manifesting itself in the form of waves. Furthermore, he added, and proved mathematically that what was true for light was equally true for electricity. Whether or not Maxwell's theory was good remained to be proven.
Heinrich Hertz was the man who by his extraordinary experiments succeeded in demonstrating the truth of this theory thereby laying the basis for future experiments in electromagnetic waves and wireless (radio) communication.
He started with the principle in mind that all electric waves resulting from rapid electric oscillations could be propagated into the air in the same way as sound waves could be generated and propagated by causing a string or diaphragm to vibrate. He surmised correctly that electric waves had tremendous speed and vibrated at a terrific rate since they could be received, like light vibrations, at a distance from the place from whence they issued.
Hertz obtained his inspirations for his experiments from these various theories. He managed to produce electromagnetic waves with the simple apparatus here illustrated. Close examination of this apparatus in its fundamental aspects (the use of coils, condensers, etc.) reveals that it differs only in method (not in principle) from the present-day system of producing electromagnetic waves. Little did Hertz realize then that these same waves later on would be the instrumentality through which all the nations on the earth would be linked together more closely than by any other means. Physicists and radio engineers the world over in celebrating, this year, the 50th anniversary of his successful experiment, acclaim his achievement in those early experiments and honor his memory.
Posted September 30, 2015