Communications: The crystal detector: By 1920, G.W. Pickard had tested 31 250 possible combinations of materials in search of a practical detector

We use the term electronics today; in 1906. the term was “radio.” Radio was a new field, and most of the technology had to be developed from scratch. For reliable long-distance communication, sensitive receivers were vitally needed. The heart of the receiver was its detector, the device that demodulated the radio frequency signal and produced an audio frequency current in the headphones that listeners had to wear. Making this detector more sensitive became the goal of every radio engineer. The inventor who did more than any other to develop the crystal detector and turn it into a practical device was an American, Greenleaf Whittier Pickard (1877-1956). Pickard, whose great-uncle was John Greenleaf Whittier, the poet, was born in Portland, Me., and educated at the Lawrence Scientific School, Harvard University, and the Massachusetts Institute of Technology. During the Summer of 1899, he received a grant from the Smithsonian Institution to experiment with wireless antennas raised by kites at the Blue Hill Observatory in Milton, Mass. His apparatus was the same as Marconi's (Fig. 1), employing a coherer as the detector, and Pickard soon became aware of its limitation.