Successful Transmission of Pictures

Radio Record, Volume II, Issue 25, 4 January 1929, Page 25

Successful Transmission of Pictures

New Service for the B.B.C.

O the average member: of' the public, the transmission of pictures probably represents an entirely new scientific development, but in actual fact it is over 20 years since the first pictures were transmitted, so that the Fultograph system, is novel only in the method by which’ the results are achieved. ; @ibe earliest. users of photo-tele-Ephy were, of course, the large daily newspapers and the systems developed for this purpose have now been brought to a very high degree of efficiency. At the same time the methods employed are extremely elaborate, expensive,. and difficult to operate. Photo-electric ‘eells are generally used both at the transmitter and receiver, so that after reception of the picture it has to be developed and printed in the same way as an ordinary photographic negative. The systems of synchronisation are ‘also in most cases somewhat trouble‘some to keep in adjustment, and at each end one or more trained operators are required. Received at. Manchester. HE broadcast: was arranged to take place between the hours of 2 p,m. and 2.45 p.m. The ‘transmissions were made from the big experimental stia‘tion, Dayentry (5XX), situated slight: Yy to the north-west of the capital. A large number of keenly ‘interested spectators assembled at 2 p.m. at the pe Poe TEEOTRTay

Radio Exhibition, Manchester, to watch the reception of the ‘first still pictures broadcast by the B.B.C. from the : London studio. For.the reception, two instruments were used, one in conjunction with a portable wireless receiver and the other with a large amplifier. This was to demonstrate that the picture receiver could be operated with any type of wireless receiver giving reasonable loud-speaker reproduction. Up to the moment of the picture transmission, music was being received on two loud-speakers, one on each set; then the announcement was heard that three pictures. would be transmitted, one’of the King, one of an aeroplane, and one of.a cartoon by Mr. Raven. Hill entitled "Seeing is Believing." Following ‘this there was heard a sustained tuning-note which had been sent out to enable the operators to. adjust the receivers correctly. This note suddenly changed to signals similar to a continuous series of dashes in. the Morse: code. Simultaneously with this change the cylinders on the picture receivers began to revolve, and the first picture transmission from a B.B.C. station had. begun. Each picture transmitted took four minutes to complete. Owing to a technical hitch only two pictures were broadcast. The picture of the King PURHMUHIHRRA i Tithe

resembled an ordinary sepia photograph and the cartoon appeared, not in "black arid white," but in sepia and white. Both were yery distinct, and that of the King was an amazingly good representation. The line drawing of the eartoon made a sufficiently exacting. test of the synchronising gear out of which the Fultograph emerged successfully. The apparatus seems singularly simple to operate, and the tracing of each picture could be watched as the transmission proceeded. The Fultograph System. HE Fultograph receiver is in two parts, the smaller of which is the rectifying panel and the larger the clockwork-driven machine with synchronising equipment on which is supported the roller, to which the sensitive paper is attached. The signal impulses which recorded the separate density of each of the little dots of which the picture is made up were sent out, it is understood, on a modulation frequency of between 4000 and 5000 eycles a second. The Fultograph transmitter was actually at Savoy. Hill and the signal impulses transmitted by land line to Daventry, where they were emitted on the ormal wavelength of 5XX. On the eylinder of the Fultograph is placed a piece of specially sensitised paper on which appears a coloured mark of density correspondTMP eee ee

ing, to the strength of the signal impulses. Further Demonstration. APART from the series of. pictures broadcast which the B.B.C. are to give from Tuesday to Friday each week, it has been arranged that demoustrations are also to take place at Birmingham, Liverpool, Newcastle, Glasgow, and Bastbourne during the week so that prospective purchasers can see the instrument. in action. The special paper on which the picture is printed will be manufactured by a well-known firm of photographie printing paper manufacturers, and is not expected to be expensive. The sensitising solution will also be marketed. Tle receiving instrument will be manufactured in England, and. two prices have been provisionally fixed for ‘-e m dels which are now on sale. One model, of oak, is listed at £22 15s., ahd the other, of mahogany, at £24 15s. These prices are exclusive of the price of the rectifying valve, which will be 10s. 6d. extra.