Greenleaf Whittier Pickard (February 14, 1877, Portland, Maine - January 8, 1956, Newton, Massachusetts) was a United States radio pioneer. Pickard was a researcher in the early days of wireless. He experimented with crystal detectors, antennas, wave propagation, and noise suppression. Crystal detectors are used in crystal radio receivers and loop antennas used with many types of receivers. On August 30, 1906 he filed a patent for a silicon crystal detector, which was granted on November 20, 1906.[2] Pickard's detector was revolutionary in that he found that a fine pointed wire known as a "cat's whisker," in delicate contact with a mineral produced the best semiconductor effect. On June 10, 1907, he filed a patent for a Magnetic Aerial (a loop aerial) which was granted on January 21, 1908. Pickard's loop antenna was revolutionary in that he found that it had directional properties that could be used to reduce interference to the intended wireless communications. Greenleaf Whittier Pickard was named after his great-uncle, the American Quaker John Greenleaf Whittier (1807-1892). Pickard was president of the Institute of Radio Engineers in 1913.[3]
[edit] Patents
- U.S. Patent 796,011 - Electrostatic separation
- U.S. Patent 796,012 - Electrostatic separation
- U.S. Patent 827,115 - Electrostatic separation
- U.S. Patent 827,116 - Electrostatic separation
- U.S. Patent 836,531 - Means for receiving intelligence communicated by electric waves (silicon detector), 1906
- U.S. Patent 840,802 - Electrostatic separator,1907
- U.S. Patent 845,316 - Means for receiving intelligence communicated by electric waves (copper sulfate solution detector), 1907
- U.S. Patent 876,996 - Intelligence intercommunication by magnetic wave component (loop antenna), 1908
- U.S. Patent 877,451 - Means for receiving intelligence communicated by electric waves (spring-loaded detector contact), 1908
- U.S. Patent 886,154 - Oscillation receiver (fused zinc oxide detector), 1908
- U.S. Patent 888,191 - Oscillation receiver (polished silicon detector, 1908
- U.S. Patent 904,222 - Oscillation detecting means (molybdenite detector), 1908
- U.S. Patent 912,613 - Oscillation detector and rectifier ("plated" silicon carbide detector with DC bias), G.W. Pickard, 1909
- U.S. Patent 912,726 - Oscillation receiver (fractured surface red zinc oxide (zincite) detector), 1909
- U.S. Patent 933,263 - Oscillation device (iron pyrite detector), 1909
- U.S. Patent 956,165 - Electrical Space Communication (interference mitigation), 1909
- U.S. Patent 1,104,073 - Detector for wireless telegraphy and telephony (looped or humped springy wire detector contact), 1914
- U.S. Patent 1,118,228 - Oscillation detectors (pairs of minerals), 1914
- U.S. Patent 1,128,817 - Valve detector for wireless (vacuum tube with conducting shield to drain static), 1915
- U.S. Patent 1,185,711 - Receiver for wireless telephony and telegraphy (interrupted or switched circuit instead of rectifier), 1916
- U.S. Patent 1,213,250 - Means for receiving intelligence communicated by electric waves (receiving circuit, divided from #836531), 1917
- U.S. Patent 1,476,102 - Optical selection of split mica sheets
- U.S. Patent 1,561,483 - Distinguishing dielectric sheets
- U.S. Patent 1,676,745 - Electrical reactance and method and apparatus
- U.S. Patent 1,907,571 - Radio Receiving Apparatus (multiple loop antennas), 1920
- U.S. Patent 1,918,825 - Extreme loading condenser
Reissued
[edit] References
- Citations
| Persondata |
| Name |
Pickard, Greenleaf Whittier |
| Alternative names |
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| Short description |
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| Date of birth |
1877-02-14 |
| Place of birth |
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| Date of death |
1956-01-08 |
| Place of death |
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