Radios
Scottish physicist, James Clerk Maxwell first predicted the existence of radio waves during the 1860?s and by the year 1886 Heinrich Rudolf Hertz demonstrated that rapid variations of electric current could be projected into the atmosphere as radio waves. It was not until the year 1900 however, that speech transmission was demonstrated by Fessenden using a spark transmitter and in 1906 he broadcast the first radio messages using 50 KHz generated by an alternator.
