441 lines – Wikipedia
The 441 lines is a television standard.
The 441 lines was used in several countries from the late 1930s and, in France, until the beginning of 1956.
UNITED STATES [ modifier | Modifier and code ]
In the United States, after an experimental phase at the standard of 343 lines from the Empire State Building, the NBC, (a subsidiary of the RCA) made several notable demonstrations in 441 lines, during the New York Fair in 1939. The format, also used by the Dumont industry experimental station, is prematurely abandoned with the official adoption, in 1941, of the 525 lines by the US FCC regulatory authority, on the recommendation of the 525 lines and the color standard NTSC (National Television System Committee).
Germany [ modifier | Modifier and code ]
In Nazi Germany, after a short experiment in 375 -line format during the retransmission of the 1936 summer Olympic Games, Joseph Goebbels created in 1937 a resort in 441 lines, emitting with Telefunken equipment in Berlin and its periphery. Ultimately, this format is supposed to succeed in 180 lines, which has operated with mechanical equipment since 1935. It has been relayed by a network of cables serving cinemas converted into “public television rooms”, in Berlin, Hamburg, Munich Leipzig and Bayreuth.
Following a bombardment on the capital which destroyed its antennas in 1943, the 441 line issuer must stop emitting. However, the station continues to operate on the wired network, distributing the signal in the “television rooms”.
During the post-war years, Germany abandoned the standard 441 lines under pressure from the United States and officially adopted the 625 lines, a European variant adapted to the alternative electricity sector at 50 Hz of 525 American lines, itself adapted to the sector at 60 Hz .
Italy [ modifier | Modifier and code ]
In Italy and France, allied or occupied countries, Nazi Germany encourages the adoption of its standard 441 lines for the future constitution of a pan -European television network, in accordance with the strategy of the Hitlerian regime.
In Turin, the engineer Castellani who works in 343 lines like the NBC, adopts the 441 lines for the experimental stations of the fascist diet in Rome and Turin. In the early 1950s, as in Germany, emissions were interrupted and left room in 625 German lines, imposed by the Americans.
France [ modifier | Modifier and code ]
In Paris, Georges Mandel, Minister of PTT, encouraged, in 1931, the Company of Counters (CDC) to carry out mechanical television tests by providing the engineer René Barthélémy a studio on rue de Grenelle. After a gradual rise of 30 to 60, then to 180 lines in 1935, the transmitter of the Eiffel Tower went to 455 line format in 1938 and therefore became the most powerful in the world (30 kW).
In June 1940, resistance sabotted this equipment to avoid its recovery by the Nazis. In 1942, the latter however decided to repatriate the equipment for their Berlin station. Lieutenant Kurt Hinzmann nevertheless succeeded in creating a station TV station Paris Alias ”Paris Television” installed in a former dance floor, the “Magic City” located on rue Cognacq-Jay at the German standard of 441 lines, in French and German language, officially for the injured or convalescent soldiers hospitalized in the Paris region .
In August 1944, disobedient to sabotage orders, Hinzmann entrusted the station intact to its French subordinates, allowing French broadcasting (R.D.F.) to restart. The 441 line format was thus exploited in October 1945 thanks to one of the most modern television facilities of the time. Hinzmann is officially thanked by the French authorities, with which he without success represents the interests of German industrialists, when the DRF decides to adopt the 625 European line format.
From 1946 to 1949, the format 441 lines reigned supreme in the premises of French broadcasting (R.D.F.) then of the new French broadcasting (R.T.F.), in particular with the creation of the television news by Pierre Sabbagh and the arrival live From the Tour de France, until the adoption of a more efficient definition intended to create a national television network. In order to avoid paying costly fees in the United States and Germany, Minister François Mitterrand adopts standard E, with definition of 819 lines, developed by Henri de France, with an AM sound instead of The FM among the Americans and the Germans and the positive polarity of the image, instead of the negative used with the standards in 525 lines and 625 lines.
In 1949, a first 819 line transmitter was inaugurated at the Eiffel Tower, operating without any link with that in 441 lines, in the absence of any solution to emit both the same video source on the two definitions. Several platform programs thus welcome both cameras and their management in the two definitions, sometimes causing incidents between the technical teams.
The regulatory authority decides that the standard 441 lines will officially cease the . The R.T.F. operates significant resources in favor of the 819 lines, to ensure rapid development, notably by acquiring mobile external shooting equipment (coaches, HF trucks, etc.). This strategy provides viewers of the 441 lines, the feeling of no longer having enough consideration from the R.T.F., offering them a limited programming to sets on set or old films.
In July 1952, on the occasion of a Franco-British week broadcast from Paris [ first ] , 819 line images can be converted into 405 lines to be broadcast on the BBC network [ 2 ] . Thanks to this device, the conversion 441 lines for the small thousand the oldest viewers in the capital is also added. A resolution monitor 819 lines equipped with an efficient cathodic tube, filmed by an also suitable 441 line camera, finally allows viewers, whatever the TV format they own, to share the same programs, especially the large direct sports and Eurovision emissions (Elisabeth II coronation, etc.).
In the night of , at the end of a long evening of coverage of the legislative elections, a fire destroyed most of the equipment of the 441 -line transmitter at the top of the Eiffel Tower. This incident produces a black screen for its last hundred viewers. Faced with the amount necessary to rebuild it while it is supposed to be permanently suppressed two years later, the government prefers to retain the solution of compensation to injured viewers, with facilities for the acquisition of a new receiver in 819 lines . The space thus released at the top of the Eiffel Tower will also allow, a few years later, to install an experimental transmitter in 625 UHF lines intended to diffuse the future second channel.
Technical specifications of the Parisian transmitter in 441 lines [ 3 ] :
- Video carrier: 42.00 MHz (polarity +);
- Audio carrier: 46.00 MHz (AM) ;
- antennas polarization: vertical;
- designation of the channel in the UER documents: “Canal S” or “Special Canal”;
- radiated power: 30 kW.
Feeders and antennas were separated for image and sound.
The transmitter reaches a theoretical range of 80 to 100 km approximately. However, in the review Practical television , some advertisements of the 1950s offer receivers guaranteeing reception up to 150 km from Paris. Certain reception points are recorded by RTF to be able to demodulate the signal with a certain stability, in particular in Auxerre (Yonne) or even Vichy (Allier).
During the Second World War, British radar technicians installed in Beachy Head, in the south-east of England, capture the emissions of TV station Paris With a 405 line TV modified in 441 lines and connected to a curtain set of 32 antennas, each dipole of which has a length of about three meters [ 4 ] .
Thanks to the exceptional scope of the transmitter and the robustness of its signal, the British secret services were able to study cinematographic news live Weekly show German and France News de Vichy giving very useful information to the allies for their operations on the continent.
external links [ modifier | Modifier and code ]
Recent Comments