Mechanical TV Sets of the 20s and 30s
The first
mechanical television systems
that produced real television images were developed by
John Logie Baird
in England and by
Charles Francis Jenkins
in the U.S. in the mid 20s.
Broadcasting began in the United States on the
AM radio band
(550-1500
kHz). In 1930, the Federal Radio Commission allocated channels
in the 2 mHz band for experimental television transmission to
allow higher resolution (45 and 60 line pictures) to be
transmitted.
Picture quality was very poor, and the screens were only
an inch or so wide and were usually made up of only 30 to 60 lines
(compared to 525 lines in the present U.S. system). Most of these sets
used a motor to rotate a metal disk to produce the picture, with a
neon tube
behind the disk to provide the light. Later mechanical systems used the
lens disk
,
mirror screw
and
mirror drum
. The
Scophony
system was the only mechanical
system capable of high definition pictures, but it was developed at a
time when the cathode ray tube had already been demonstrated as a better
method of displaying television pictures.
By 1931, television was being
broadcast
from about 25 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.
he frequencies used for TV broadcasting at that time
could travel long distances, so reception was possible hundreds of miles
from the station. However, the pictures suffered from not only poor
resolution, but also fading and ghosting.
In Columbus, Ohio, Murray Mercier, born in 1912, was one
of the first people to watch television. Here is
his story
.
In England, regularly scheduled 30 line television
programming was first broadcast by the
BBC
in September of 1929.
At first, only the picture was transmitted for a few hours a week, after
regular radio broadcasting was completed for the day. By March of 1930,
sound and pictures were transmitted together. Most countries in
Europe had at least one
mechanical
station
.
Because of the poor picture quality, mechanical television
was not a success. By 1933 almost all stations were off the air in the
United States. Mechanical television transmission by the BBC continued
until 1935, and in the
Soviet Union
until 1937.
These sets are in our
collection
Click on the
Image for More Information
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Baird Televisor (1930)
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Baird Replica (1950?)
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Color Mirror Screw Receiver (1933/2007)
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Daven TV Receiver (1928)
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Daven Tri Standard (1928)
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Fracarro 30 Line (ca 1930)
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General Electric Octagon Replica (ca 1950)
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Hollis Baird Receiver with Globe Scanner
(1929)
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Hollis Baird C-3-S Shortwave Converter (1930)
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Hollis Baird 35 Receiver (1930)
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Jenkins
JD-30 Receiver (1932)
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Jenkins 100 (1931)
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Mercier 24/45 Line (1928)
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Mercier 60 Line (1929)
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Mervyn Mirror Drum (1934)
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RCA 60 Line (1931)
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Shortwave Converter (1928)
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Western Visionette (1929)
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Western Empire State (1931)
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Daven Equipment (1928)
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Jenkins JK-20 TV Reciver Kit Box
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Phol Paper Scanning Disk
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Radio Television Institute Phototube (1936)
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