Mechanical Television

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In June of 1923 Charles Jenkins, an inventor from Dayton, Ohio, invented and transmitted the earliest moving images through a mechanical television system called Radiovision. He publicly performed his first transmission, from Anacosta, Virginia to Washington in June of 1925. As far back as 1894, Jenkins had been promoting mechanical television when he published an article in the "Electrical Engineer” describing a method of electrically transmitting pictures. In 1920, at a meeting of the Society of Motion Picture Engineers, Jenkins introduced his prismatic rings, a device that replaced the shutter on a film projector and an important invention that Charles Jenkins would later use in his Radiovision system.

How It Works

The transmitter had to be set in a studio in total darkness. Holes would be punched in a spiral disc would allow only light to be passed through these selective regions. The spinning disk would emit light bounced off of the subjects face from a light source within the transmitter onto a photoelectric cell that would convert the light image into electric signals. These would, in turn, be amplified and sent via radio waves to a receiver on the other end.

The receiver on the other end would convert these electric impulses into a sequence of bright flashes in a neon tube located within the receiver. A disc would rotate very rapidly in front of this tube and converted every small flash into a part of the overall image. The speed of the disc would make “persistence of vision” (when the brain retains an image for one tenth of a second after the eye perceives it) possible for the viewer. Originally the image was very scratchy and the picture had to be constantly adjusted. This made some technical knowledge a necessity thus shrinking the prospective demographic to a select few (mostly men) who knew how to operate these machines. There was also originally no audio to accompany the pictures. Sepreate radios had to be purchased, or used if the viewer already had one, and tuned into a seperate station that would supplement the noises and music for the show they were watching.