Happy Birthday Heinrich Hertz

Happy Birthday Heinrich Hertz

February 22, 1857 – January 1, 1894

A pioneer of radio signals and as a consequence the future of radio, all that is possible for wireless originates from the early discovery made by Heinrich Rudolf Hertz (http://en.wikipedia.org/wiki/Heinrich_Hertz) in proving the existence of radio waves. His pioneering works made reality that which was theorised of James Clerk Maxwell (http://en.wikipedia.org/wiki/James_Clerk_Maxwell) discoveries, commonly referred to as Maxwell's Equations how electric charges and electric currents act as sources for the electric and magnetic fields by defining a series of equations for electromagnetism. In science lessons, apart from being reminded that radio waves are analogue in nature, sometimes lecturers may visually demonstrate the forces of electric and magnetic fields using the hand reference: thumb, index finger and middle finger. The thumb represents a active 'source', the index finger represents 'electric field' and the middle finger represents 'magnetic field' at right angles to the electric field.

Hertz demonstrated the existence of radio waves in experiements using two rods that served as a receiver and also a spark gap as the receiving antennae, so that where radio waves were detected a spark would jump, demonstrating radio signals possessed the properties of electromagnetic waves. Moreover, his work is attributed to identifying that radio waves have (i) a 'time' factor and (ii) that the velocity of radio waves was equal to the velocity of light.  Hertz experiements revealed to him how to separate (thus detach) electric and magentic fields from wires and roam in free space; or as Maxwell is attributed to have put it the 'ethereal wind'. 

Hertz
The unit of frequency of a radio wave is referenced as 'one cycle per second' and is named the 'hertz'.

Digital Signalling Background
http://trewmte.blogspot.com/2009/01/mobile-forensics-and-evidence-degrees.html

Happy Birthday Hans Christian Ørsted (Oersted)

Happy Birthday Hans Christian Ørsted (Oersted)

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Hans Christian Ørsted, one of the leading scientists of the nineteenth century, played a crucial role in understanding electromagnetism. In 1820 he discovered that a compass needle deflects from magnetic north when an electric current is switched on or off in a nearby wire. This showed that electricity and magnetism were related phenomena, a finding that laid the foundation for the theory of electromagnetism and for the research that later created such technologies as radio, television and fiber optics. The unit of magnetic field strength was named the Oersted in his honour.

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http://chem.ch.huji.ac.il/history/oersted.htm

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James Clerk Maxwell

Would Ørsted's work have influenced James Clerk Maxwell? To research here are a few links that records Maxwell's published works and other historical events:

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www.clerkmaxwellfoundation.org/PUBLISHED_SCIENTIFIC_PAPERS.pdf

http://www.phy.cam.ac.uk/library/libraryfiles/clerkmaxcoll.pdf

http://simple.wikipedia.org/wiki/James_Clerk_Maxwell

http://simple.wikipedia.org/wiki/Electromagnetism

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Relevance: these matters all relate to the fundamental building blocks of radio signals, not forgetting, of course, that although we operate today in a digital radio society the waveform of radio signals are still analogue by nature. It is the adopted modulation schemes that define the important information we know that hides and is transported inside the radio signals - data.