When tubes beat crystals: early radio detectors

Just after the turn of the century, when researchers on wireless communication were avidly seeking new ways of detecting weak radio signals, two major contenders appeared: the crystal detector and the thermionic diode detector. The two devices were associated inseparably with two disparate personalities: the obscure H.H.C. Dunwoody, who espoused the crystal detector, and the famous J.A. Fleming, who promulgated the vacuum-tube detector.