“This is truly scientific magic. Just think of it! You want to know the true time to the fraction of a second, and all you have to do in order to get it is to open your electric ear to these sounds, which seem to drop out of the sky, as if Old Time himself were speaking to you!”
―Garrett P. Serviss, Wireless Time Signals from the Eiffel Tower. Washington Post, September 7, 1913.
During 1913 the Washington Naval Observatory and the Observatoire de Paris attempted to exchange wireless time signals. The experiment was used to calculate the difference in longitude between the two locations more accurately than was possible with other techniques. They were also trying to measure the velocity of radio waves through space. The goal was to improve communication with ships at sea which used the time signals to calibrate the chronometers used for celestial navigation. For most of the year atmospheric conditions prevented the reception of the signals sent across the ocean. The conditions improved in November and the two observatories were then in regular contact by radio. Prof. Winslow Upton of Ladd Observatory was listening in on the transmissions.
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. The chronometer was later modified to include a telegraph break circuit by William Bond and Son of Boston. His notebook also contains calculations showing how the chronometer was calibrated by comparing the time to the Clemens Riefler astronomical regulator in the clock vault at Ladd. The wavelength of the transmission was 3,500 meters, or about 85 kilohertz. It was not possible to receive the Paris signal from Providence as this would have required a very large antenna.
The U.S. census for 1910 lists Abner Donle and his wife Miriam living at 9 Phillips Street, which is on the block adjacent to the Observatory. Also living at this address were two sons. Earl, 20 years old, was employed as a draftsman at an engineering firm. Harold, 22 years old, gives his occupation as a “manufacturer of wireless apparatus.” In 1912 Congress passed An Act to Regulate Radio Communication which required anyone operating a wireless station to hold a license from the government. Harold P. Donle was issued the call signal 1UD to operate an amateur station with a 300 Watt transmitter. Curiously, his address is given as 18 Observatory Ave. but there is no house at this location during that era. The only nearby building was an auxiliary observing shed owned by Ladd Observatory.
Harold later worked for the Connecticut Telephone & Electric Company and was granted a number of patents between 1917 and 1939 for the “wireless apparatus” that he invented. But, in 1913 the young “ham” radio operator collaborated with an astronomer from Brown to participate in a global experiment in the exchange of precision time signals.
Winslow Upton died suddenly in January of 1914 before he could complete the calculations of the difference in longitude between Providence and Washington.
“During November and December Professor Upton availed himself of the Paris-Washington wireless signals to obtain data for a more accurate determination of the longitude of the Observatory. Whenever the Washington readings and corrections are available, the observations will be reduced.”
– Prof. R.G.D. Richardson to the President of Brown University, 1914