From the link: > Radio time signals for setting chronometers were sent from stations such as NAA in Arlington, Virginia, which began broadcasting in 1913. The

From the link: > Radio time signals for setting chronometers were sent from stations such as NAA in Arlington, Virginia, which began broadcasting in 1913. The time was supplied from a direct communication line with the clocks of the U.S. Naval Observatory in Washington, D.C. In combination with another low-frequency installation mounted on the Eiffel Tower in Paris, the towers had the range to cover the North Atlantic Ocean and the eastern United States. So I looked up the Eiffel tower. > The Eiffel Tower time signal broadcasts began on May 23, 1910 https://tf.nist.gov/general/pdf/2131.pdf https://tf.nist.gov/general/pdf/2131.pdf Also, same source starts with the 1898 proposal of time sync via radio being made by an Irish bloke. > I don’t know who had the first system accessible to civilians, but at this point we’d just be arguing details. Agreed. Even non-civilian, and whoever came first, the timeline of things across various countries, I don't think the core point of TFA holds water: it's not a "particularly American" thing, it just made sense out of engineering requirements: time sync was transmitted over telegraph wires, and telegraph went wireless; the leap is not exactly surprising.