Early TV

"The first mechanical television systems were developed by John Logie Baird in England and by Charles Jenkins in the U.S. in the mid 20s.
Picture quality was very poor, and the screens were only an inch or so wide and were made up of only 30 to 60 lines (compared to 525 lines in the present U.S. system). These sets used a motor to rotate a metal disk to produce the picture, rather than a picture tube. A neon tube behind the disk provided the light.
By 1930, television was being broadcast from over a dozen stations in the U.S., not only from the major cities such as New York and Boston, but also from Iowa and Kansas. Several manufacturers were selling sets and kits. ..." Read more here.

Farnsworth 1945 Prototype (1945) & Baird 165 (1949)

Early Television Museum (via Paperholic)