441-line television system
441-line is the number of scan lines in some early electronic monochrome analog television systems. Systems with this number of lines were used with 25 interlaced frames per second in France from 1937 to 1956,[1] Germany from 1939 to 1943,[2][3] Italy from 1939[1] to 1940, Japan in 1939,[4] as well as by RCA in the United States with 30 interlaced frames per second from 1938 to 1941. Broadcasts were planned in Finland for 1940,[1] but eventually cancelled due to World War II. Some experiments with a similar system were carried out on the USSR in the 1930s.[1]
Telefunken FE V television (1936)
Telefunken FE VI television (1937)
Einheitsempfänger E1 television (1939)
Einheitsempfänger E1 chassis (1939)
Television in a Berlin military hospital, setup by the German Reichspost (1942)
After trials with a 375-line system during the Berlin Olympic Games of 1936, by 1937 Germany had introduced a 441-line with 50 interlaced fields per second television system that replaced the previous 180 lines network relayed by a special Reichspost (National Post Office) cable network in the country's main cities (Berlin, Hamburg, Munich, Bayreuth, Nuremberg). The system's line frequency was 11.025 kHz and the broadcast frequencies were 46.0 MHz for vision and 43.2 MHz for sound, using a 4 MHz channel bandwidth.[2] Its image aspect ratio was close to 1.15:1.
A project began in 1938 involving the National Post and several companies including Bosch, Blaupunkt, Loewe,[5] Lorenz, TeKaDe[6] and Telefunken[7][8] that aimed to produce 10,000 receivers for the television system.
Telefunken marketed the FE V, announced in 1936, with a 26 x 21 cm screen and a tuning range of 38-60 MHz.[9] The next year, 1937, the Heimprojektions-FSE was introduced, with a larger 50 x 40 cm screen, along with the FE VI with a 26 x 21 cm screen.[9][8] In 1938, the Tischfernseher TF 1 was released, with a 20 x 17 cm screen and a tuning range of 40-55 MHz.[9]
In 1937, Loewe created the FE-D, with a 24x20 cm screen and a tuning range of 35-55 MHz.[5]
In 1938, TeKaDe created a single model, the FS38, with a 30 x 27 cm screen and a tuning range of 43-52 MHz.[6] Other brands like Fernseh AG also created models like the DE 6, also introduced in 1938, with a 32 x 27 cm screen and a tuning range of 40-53 MHz[10]
A single-channel TV receiver, the Einheitsempfänger E1 was created in 1939.[2] It had a 29 cm (diagonal) screen, and consumed 185 watts when receiving television signals and 60 watts when receiving audio only.[2] Only a few units were built before the outbreak of World War II.
Due to the onset of World War II, only about 50 devices were installed in military hospitals and various government departments. The transmitter's aerials in Berlin were destroyed during an Allied Forces' bombing in November 1943, but the station was also relayed by a special coaxial cable network to "wide screen" public "TV-rooms" (Fernsehstuben) so it carried on this way until 1944.
Italy[edit]
Following pre-war tests in 375 lines done by a Turin engineer named Arturo Castellani,[13][14][15][16] broadcasts using the 441-line system began in Italy in 1939[1][17] with regular services from Rome using 2 kW power and Milan using 400 W of power in the frequency band of 40-45 MHz.[12] As in France technical parameters – VHF frequencies excepted – were identical to those in use in Germany.
Broadcasts were discontinued on May 31, 1940.[18]
Ad for the beginning of RCA experimental television broadcasting (New York City, 1939)
FCC inspects the latest in television (Washington, D.C., December 1, 1939)
General Electric HM-171 television set
General Electric television sets from 1939: HM-185, HM-226-7A, and Model 90.
In September 1938 the Radio Manufacturers Association (RMA) recommended the 441-line system[21] developed by RCA and Farnsworth Television.[22][23][24][25][26] Tests started a year before, in an attempt to perfect a 343-line system,[23] with RCA executives petitioning the FCC for approval of their new standard.[27] In early 1938 Philco's experimental transmitter W3XE in Philadelphia was already using the system.[21][28][29][26]
TV broadcasts were publicly launched in April 1939 by NBC, during the New York World's Fair, using the W2XBS station.[30] The first pre-built TV receivers were sold on a very limited basis, mostly in New York City. Manufacturers included RCA,[31] General Electric,[32] DuMont,[33] and Andrea Radio Corporation.[34][35]
By June 1939, regularly scheduled broadcasts were available in New York and Los Angeles. By October nineteen TV broadcast licenses had been issued, including stations in New York, Philadelphia (W3XE), Chicago, Washington, Fort Wayne, Cincinnati, Schenectady (W2XB), Los Angeles and San Francisco.[30]
By November General Electric's station in Schenectady started broadcasts. W2XBS in New York broadcast up to fifty-eight hours of programming per month until December 1939, to an estimate of 2,000 receiving sets. Reception area was a radius of 40-50 miles (80 km) from the Empire State Building.[36]
Following a decision of the NTSC (National Television System Committee), the 525-line standard replaced the 441-line standard on July 1, 1941.[37]
Soviet Union[edit]
In the Soviet Union a specification for a 441-line system using 50 interlaced fields per second was proposed in 1940. Development of this system started in the 1930s, derived from test broadcasts from Moscow, using a 343-line system based on RCA equipment.[38][39][40] Due to World War II the 441-line system never reached the broadcast stage.