Harold P Donle was a prolific inventor born in Providence, March 4th 1888 to Abner D and Miriam Donle 1. In 1913 he is listed as owning 300 watt amature radio license 1UD 20 at 18 Observatory Avenue in Providence, RI. This is right across the street from the Ladd Observatory 2.
It seems Mr Donle worked with Professor Prof. Winslow Upton of Ladd Observatory receiving time signals from the Eiffel Tower as part of a experiment used to calculate the difference in longitude between the two locations more accurately than was possible with other techniques. Winslow Upton describes how the Washington wireless signals were received at Mr. Donle’s house and compared to portable chronometer #2299 made by Charles Frodsham of London, circa 1850. 22
He was drafted into WWI in 1917 3 and although 54 he was drafted into WWII in 1942 13. Education at this point has not been established although he is listed as a student at about age 21 in the 1909 Providence street directory 14. Mr Donle held 47 Patents ranging from a Heater Pad 6 to Television 7.
In 1910 15 and 1911 16 he is listed as a Wireless Electrician. Also we see in 1911 and 1912 17 he has a younger brother who was a student at Brown University, class of 1911 21 . Then in 1914 18 and 1916 19 he is listed as working as an Electrical Engineer for Lindbridge Company, 632 Indstrial Trust Building, Providence.
Many of the patents have to do with Radio and Telephone. Companies he worked for when applying for these patents were Connecticut Telephone and Electric Company from 1917 to 1929. In 1929 his patent for a "Radiodetector" 8 is listed under RCA. Starting in 1930 his patents start being listed under Radio Inventions Inc 9 and continue to be up to 1936. In 1937 he has one patent list under just his name for "System and method for securing third dimensional effects with a single image" 10 and finally in 1937 he has two patents for "Electronic tube circuits" 11 and "Bridge circuit" 12 for the American Radiator & Standard Sanitary Corp. In his life time he lived in Rhode Island at least until 1913 when he got his amature license and then Meriden CT while he was chief engineer for the Connecticut Telephone and Electric Company. In the 1940 census he is listed as being a lodger in New York, NY. He was married to Marion Donle, also from Rhode Island, and they had 5 children. In 1909 he is also listed as having produced high class wireless instruments5 of his own design that were within the means for everyone to own ($9.00) and were powerful, efficent and finely finished receiving sets. His most interesting patent however is one for "System and method for securing third dimensional effects with a single image 10 or 3D filed in 1933 and granted in 1937!
Hi claim to fame however is his Sodium Detector as reported in the February 1923 issue of Radio Age Magazine 4.
Mr Donle died in 1942.
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External-Anode Vacuun Tube
A New Non-Oscillating Tube
My New Noninterfering Detector
The Most Sensitive Tube In The World
The Truphonic Amplifer
A Synchronized Tuned Radio Frequency Receiver Employing Donle Truphonic System of Amplification
A New Method of Amplifier Coupling, September, 1926
The New B -6 Donle Detector, September, 1926
H P Donle Tubes
KB-8 Receiving Set
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2 Licensed Amateur Stations, First Radio District, June 3, 1913
3 WWI Draft Card
4 Wireless Age, February, 1923
5 Electrician and Mechanic, July 1909
6 Heater Pad
9 Radio Inventions Inc
10 System and method for securing third dimensional effects with a single image
11 Electronic Tube Circuits
12 Bridge Circuit
13 WWII Draft Card
14 1909 Providence, Directory
15 1910 Providence, Directory
16 1911 Providence, Directory
17 1912 Providence, Directory
18 1914 Providence, Directory
19 1916 Providence, Directory
21 Historical Catalogue of Brown University, 1764-1914
22 “The Magic Voice of Science”