Charles Francis Jenkins (1867 - 1934)
One of the better known experimenters with mechanical television was Charles Francis Jenkins, a prolific American inventor. In May 1920, at the Toronto meeting of the Society of Motion Picture Engineers, Jenkins introduced his prismatic rings as a device to replace the shutter on a film projector. This invention laid the foundation for his first "radiovision" broadcast. He claimed to have transmitted the earliest moving silhouette images on June 14, 1923, but his first public demonstration of these did not take place until June of 1925.
Jenkins Laboratories constructed a "radiovision transmitter", W3XK, in Washington D.C. The short-wave station began transmitting "radiomovies" across the Eastern U.S. on a regular basis by July 2, 1928. Jenkins wrote in 1929:
"This gave the amateur action-pictures to 'fish' for; and during August following a hundred or more had finished their receivers and were dependably getting our broadcast pictures, and reporting thereon, to our great help."
It was in this way that Jenkins actively promoted enthusiasm and experimentation in the short-wave radio community, and the U.S. experienced its first television boom, with an estimated 20,000 "lookers-in".