Lee de Forest is known as the "father of radio" for his invention of the triode
tube, audion.

The tube served as a generator, detector, and amplifier of radio signals, and
at the time was the most important invention in the field of electronics. De
Forest's first patent was for an electrolytic detector.  The audion patent of
1907 was contested by those who thought it too closely resembled John Fleming's
diode tube.  The U.S. Supreme Court in 1934 upheld De Forest patent claim.

He had more than 300 patents.  In 1909 he demonstrated the first broadcast of
music, the singing voice of Enrico Caruso.

De Forest also developed innovations for long-distance telephone service and
facsimile transmission, color television, and automatic dialing services.