PICTURE BROADCASTS.

New Zealand Herald, Volume LXV, Issue 20074, 11 October 1928, Page 6

PICTURE BROADCASTS.

THE BRITISH, EXPERIMENT. TJie announcement that the 8.8.C. is beginning " still " picture transmissions by the Fulton process is not surprising. The process, which should not be confused with television, is a comparatively simple one at the receiving end, and the pictures are ready to be viewed immediately the transmission t is over. To broadcast a picture 3iin. by 4jin. takes about 34 minutes, so the 8.8.C. sacrifices little Broadcasting time in making the experiment. The apparatus, invented by Captain Otho Fulton, is comparatively siimpTe. The photograph, in the form of prepared copper foil, is wrapped round a cylinder, which is rotated at about 50 revolutions a minute by means of clockwork, a contact needle slowly traversing the cylinder and acting in much the same way as the needle of an old-fashioned phonograph. At the receiving end a contact point slowly traverses a chemically-prepared sheet of paper, wrapped round a cylinder almost identical with that at the transmitter, and worked by a similar clockwork motor. Line by line, the paper is marked by the electrolytic action of current passing from the needle through the paper to the cylinder underneath. The positive on copper, usedl at the receiving end, takes about three-quarters of an hour to prepare. The picture to be sent is photographed ,through a» line screen not unlike that used in process-engraving, and from the negative a print is made on copper by the bichromate process. This depends on" the fact that fish-glue containing bichromate of potassium becomes insoluble when exposed to light. Thus' some parts of the finished picture are covered with glue, while in others the copper is almost bare. The glue is an insulator, so as the picture is traversed by the contact needle electrical impulses are conveved to the wireless transmitter.

At the receiving end a two-valve amplifier is used to magnify the impulses given to a needle traversing the chemicallytreated paper, which turns a brown colour varying in depth according to the amount of current flowing. The two cylinders are synchronised approximately by a simple electro-magnetic relay device fitted to the receiver and operated once at each revolution of the transmitter.

The process is an entertaining novelty, but it is hard to imagine any general demand for picture transmissions.

NOTES AND COMMENTS. The dramatic fantasy,' "Hearts tq, Mend, ' produced at IYA last Thursday by Mrs. Bartley-Baxter, was a delightful piece of work and a good example of what may bo done in this way. There were only three characters, Pierrot, Piorette and a tinker. The adroit use of music, a daintilyspoken prologue, a few words here and there to indicate "business," and somo slight sound-efiects gave all the atmosphere that could be desired. Many listeners will hope that the same lady will provide more such entertainments in future .

The New South Wales Broadcasting Company has inaugurated an important service to assist listeners in getting better reception of its stations. 2FC and 2BL. If a listener has any technical difficulty in getting good reception he is asked to send full particulars to the company, and the engineering staff will do its utmost to afford a solution. It frequently happens that the- stations are blamed for bad transmission, when the real fault is with the receiving apparatus. Some small and inexpensive adjustment or addition may be all that is needed to improve the reception. In any event the engineers will do their best to assist listeners who send complaints, with full details of their receiving sets.

Nearly 500 wireless valves comprise an important part of the supplies carried by the Byrd Antarctic expedition. The exact number is 483, of which 95 axe for transmitting and 387 for receiving. Such a quantity is being taken to make communication certain. However, should the supply become low it is planned to rebuild receivers and transmitters to accommodate a smaller number of valves. Latest-returns of licensed listeners show that at the end of August there were 141,344 licences for radio reception issued in Victoria, as against 84,900 in New South Wales, which works out at 8.01 licences for every 100 people in Victoria, and -3.05 per 100 of the population of New South Wales. The Post Office Department and radio dealers are convinced there are several thousands of licence defaulters in New South Wales, and new efforts are being made to discover owners of radio receiving sets who have not paid their licence fee for the current year. A portable "mixing panel" for use in theatre and church relays requiring more than one microphone has been designed and built for 2FC, Sydney. It intervenes between the microphones and the usual amplifier and enables the relay operator to combine the output of several microphones in different parts of the building in any desired proportion or to change from one to another without letting listeners know that it is being done. Some of the Eucharistic Congress ceremonies require seven microphones, so the need for such a device is very obvious. Without it, the transmission would be "thick," owing to the slow-moving sound wavei reaching the various microphones at different times. The apparatus is contained in a small leather case and weighs 51b.

Aq American insect, known as a shadfly, completely stopped the transmission of station WGY, Schenectady, while it was relaying an important speech by Senator James Reed at the Democratic National. Convention recently. The senator was getting into the full tide of his argument when the fly, which had been exploring the transmitter, flew between the plate- of a great condenser. It was electrocuted, and its passing caused an arc. Thin instantaneously shut down the motors which supply cooling water to the power valves, which automatically opened a circuit and put tho station off the air. Before the cause of the accident had been ascertained and repairs effected Senator Reed had ceased speaking. Governor Al. Smith was listening to the transmission of the speech when it was suddenly stopped. He thought that the studio was "censoring" Senator Reed, and by telephone indignantly wanted to know why. The Governor was mollified when lie heard the explanation, which he accepted, but was disappointed that such a good fighting speech did not reach tho ears of thousands of potential supporters.