PICTURES AND WIRELESS

Evening Post, Volume CVI, Issue 55, 14 September 1928, Page 14

PICTURES AND WIRELESS

B.BiC "STILLS" & TELEVISION Picture transmission has now entered the field of evory-day broadcasting in Britain. The British Broadcasting Company is, judging from published comments and its official statements, one of the notably conservative institutions of tho world, and the fact that it has begun broadcasting news pictures indicates that the process is a thoroughly practical one from the private receiver's point of view. _ For somo years now, of course, picture transmission has been a great success when cost has not hud to be considered, and newspapers, police, and other interests have used it to quite a large extent. Tho past year or two has been marked by great activity in the direction of bringing picturo reception within the reach of the multitude, by providing a. simple, reliable, and inexpensive "device capable of being used in conjunction with an ordinary receiver. A picture comparable with an ordinary newspaper print in clearness, and about four inches by five, can be transmitted in a few minutes. It must be emphasised again that picture transmission is not television. This also has been "featured" in the cables, owing to the first public demonstration of the simultaneous broadcasting of sound and vision. Tho experiment was carried out by the General Electric Company, and the subject was a play. Although tho cable reported that the demonstration was carried out between two rooms, a Wellington shortwave enthusiast informed "Grid-Bias" that he heard the transmissions clearly from stations 2SAF and 2XAD, and gave an outline of the play, "The Queen's Messenger." He states that the sound of the television broadcast, a continuous "trilling," was quite strong and clear, but, of course, conveyed no impression beyond tha^ of a noise. Lest unreasonable conclusions bo drawn from this announcement, it must be added that the demonstration indicates no appreciable advance in the transmission of a view of a moving object. What it did, however, was apparently to break away from previous public experience by showing something more than a small object under special illuffiination. It can be accepted as certain that every possible effort wil bo made to exploit the pos-

sibiliites of television devices such as aro now available; but these possibilities are subject to extremely severe limitations. Nobody has yet been able to "televise" anything but a very small picture of very coarse structure, and even to do that requires such a great number of electrical impulses as to roach the limit of mechanical handling, and to cause grave embarrassment to radio engineers. Those who aro acquainted with tho theory of broadcasting know that a carrier wave is "spread" by modulation until it covers a band of frequencies, the width of which lias had in some cases to be artificially limited to prevent interference. Even such television as is now under test uses still higher frequencies and a still wider wave-band, and the better television becomes—as long as it depends on the known principles— the worse it will be as a source of congestion. Owing, however, to mechanical difficulties —there is at present no visible prospect of any notable extension of this frequency band. The next step in television promises to be a far bigger one than all those which have led to the present state of the process. .