“VIDEO" ART

Evening Star, Issue 22619, 10 April 1937, Page 4

“VIDEO" ART

PROGRESS IN ITALY Considerable activity and l developmental improvement in Italy in tue “ video ” art is now apparent to the 1 Radio News’s ’ television reporter after an examination of their latest television instruments. The faafar organisation, which is the only manufacturer in that country producing this kind of equipment, has recently _ demonstrated a new 15-tubo television receiver using a huge cathode-ray tube that gives high-definition television recaption in actual blacli-and-wnite images. The system used is that of Arturo Castellani, head of the Italian Laboratory for Television Researches. The development of this new receiver and of the transmitting apparatus, which uses wave lengths between 5 and 7 metres, follows a course somewhat parallel ; with, those . of . Farnsworth R.C.A., and Philco in America, and Baird in England, Telefuhken in Germany, and other developments in France, Russia, and Japan. The apparatus, however, has been worked out with such ,a regard to fidelity in reception and fineness of manufacture that it should be brought to the attention of television enthusiasts everywhere. . . . ~ Safar first-started its television activities in 1930, and its first successful tests were carried out at Milan at the National Radio Show of that year. The first transmissions and receptions employed Nipkow discs with a synchronisation system using impulses transmitted along with the signal. These first (images were,’of 60. lines and 25 frames a •Second. if ? . ,- ~ In 1931 the company instigated the establishment of experimental laboratories for the development of luminous gas lamps and other types of tubes for television. In 1932 a new disc receiver with a mercury-vapor lamp was demonstrated, and a rather successful experimental service through the period_ the show was held. This included an ultrashort wave television transmitter working on 7 metres with 100 watts power. After that a Ikw transmitter was developed and ■ installed, and tests were made with various early types of , cathode-ray tubes, including a whole series of experiments with different kinds of fluorescent substances. The first public demonstration of cathoderay television in Italy was made with 130 and 240 line transmissions utilising frequencies from 25 to 1,000,000 cycles wide. During 1933 and 1934 the researches were advanced, and a 13-tuhe system was developed utilising the Safar Televisode M cathode-ray tube, with an image of 180 by 210 millimeters. In 1935 the development progressed to a point utilising similar, but improved, equipment, with 240 lines and 25 frames a second. This development was _ continued through 1936, and resulted in the present apparatus which transmits and receives scenes, in artificial or ordinary daylight and gives a dimensioned picture of 240 by 220 millimetres using 375 lines and 25 frames per second in a perfectly black-and-white picture. The system transmits and receives the television signals on 7 metres with the sound accompaniment on 6.7 metres. In the newest receivers the large cathode-ray tube is mounted on a rigid metal frame (duralumin), into which it sets, with the fluorescent screen at the top. A 45deg mirror projects this image so that it can be seen through an opening in the upper-front portion of the cabinet. There are three controls used in this system, which are shown in the illustrations. The loud-speaker is also mounted on this frame. The receiver itself is made in two parts, which are hinged so as to be easily serviced, each part folding down into one-half of the receiver chassis proper. One portion contains the power apparatus and the sweep circuits, etc., and the other contains the r.f. receiving circuits. This latest job uses a total of 15 tubes. The price of the complete receiver runs somewhere between 450d0l and 500dol at the present rate of exchange. The cathode-ray tubes are priced at about 60dol, and are guaranteed to give 2,500 hours of operation. The whole receiving apparatus weighs slightly over 1201 b. Further experimentation and development is being carried on with the idea of establishing a chain of television stations employing the Castellani system throughout tho length of the Italian Peninsula, possibly connected by a coaxial cable, for transmission of both sight and sound programmes. According to present plans, each station will have a practical working range of approximately 20 to 25 miles.