Radio Craft Magazine, August 1935 Television Number
Presenting the Multiple-Image Television Receiver
The August, 1935 issue of Radio Craft magazine
shows a futuristic image of a triple-screen television. The purpose of
this set, which was never manufactured, was to let a group of
people view the picture from different angles.
Television of the 1930s was an exciting, but still largely experimental,
technology. Although mechanical scanning-disk TVs had been superseded by
all-electronic sets, electronic picture tubes were still very small. A
television of the time might have had a five-inch picture tube, whose
image was enlarged by reflection onto a mirror or projection onto a
The cover article was written by Hugo Gernsback, a prolific writer
and the publisher of many magazines covering electronics and
His article describes possible methods
for building a multi-screen TV. One method uses a single
picture tube with three emitting guns, each one directed
at a separate screen.
As with many visions of the future, this one was literally incorrect yet
strangely prophetic. Nobody built the three-picture tube that Gernsback imagined, but
his idea was realized in modern color TVs. Every color picture
tube has three emitting guns, which create three identical images in
the colors red, green, and blue.
Instead of pointing the images in three different directions, the
color tube superimposes them exactly in one image. In this way,
the combination of R, G, and B can create any color of the rainbow
in each of the picture tube's thousands of phosphorescent dots.
In tube color TVs, convergence is the
process of adjusting the three guns' images to coincide
exactly. This is an exacting and delicate procedure, as
I learned when starting to restore my
RCA CTC-11 television.