NEWS AND NOTES

Nelson Evening Mail, Volume LXXII, 16 July 1938, Page 15

NEWS AND NOTES

Shortwave for New Zealand? Indicating that the work of constructing the new Broadcasting Centre at Wellington would be proceeded with as soon as the remaining preliminary obstacles were removed, the Rt. Hon. M. J. Savage, Minister of Broadcasting, said that it was not possible, however, to give any estimate of the time that would be involved in its construction or any idea as to whem the work would begin. Mr Savage was asked whether

the Government would consider the advisability of pushing ahead with the j construction of the proposed short- j wave broadcasting station as early as j possible with the object of having it on j the air for publicity purposes during the centenary of 1940. In reply he said j that consideration would be given to | this matter. It would undoubtedly be of value to the Dominion to have a short-wave transmitter on the air, and the Government might even consider the possibility of constructing a transmitter in New Zealand if it was thought advisable. A Profitable Station The church of Latter Day Saints proposes to erect a huge short-wave station (for which £300.000 is available) near Salt Lake City. Its obpect is to; keep one thousand Morman missionar- : ies, spread over the world, in touch with their home church. The Saints run a commercial station, KSL. at Salt' Lake, and net a profit of approximately £IO,OOO a year from it. The Radio Language It was early realised that radio technicians had evolved a “language of their own. As proof of this, it is necessary to tune in on the amateur band any Sunday afternoon and listen to the conversation exchanged by these enthusiasts. When an amateur tells his friend in another State he is getting his signals R 6. he really means they are coming in very strongly. Hereunder is to be found a full list of these audibilities, given by “Spark Gap” in the July issue of “The Australian Journal.” Director of 8.8. C. Sir John Reith is leaving broadcasting to go to the Air Ministry, but the 8.8. C. will carry on. If it failed, most of the humorists of the London Press would be at their wits’ end to beat up] targets. Gigantic Aerial Tower The N.B.C. of U.S.A. has just erected a new steel aerial tower for its 50.000 watts transmitter, WGY. at Schenectady, N.Y. The tower is 625 feet high, land is expected to greatly increase the j range of the mammoth transmitter | without interfering with the signals of other stations. The steel structure, nine feet square, weighs over 200 tons, but is borne on a porcelain base only 20 inches in diamater. Although the tower occupies so little space, the earthing system uses up 20 acres of ground, thirteen miles of heavy copped wire being buried in the soil.

A Novel Invention. I A wonderful invention is to be seen \ at the International Business Machines' Building in New York. It is the radio- j 1 typewriter, consisting of an ordinary | typewriter resting on a cabinet con- i taining a radio apparatus. A message! typed on the machine is converted into j signals which flash through the ether! and descend on another typewriter, set- , ting its keys going furiously. Even in « a city like New York, which is literally ■ teeming with broadcasts all day and ] night, there remains a little zone of . ultra-short wave lengths, of which the ] inventors have been able to take ad- , vantage, and it is estimated that as' , many as 5000 such machines could be \ used at one time in the city without ( interfering with each other. Exactly what the uses of such a machine will . turn out to b,e in business remains , to be seen, but that the wireless typewriter “works” has been amply proved. . j Recording Technique. j The processes and technique of pro- | gramme recording have been develop- ' j ed to such an extent that for the most | Part the results as heard through the ' ! average station and receiving set cannot easily be distinguished from an origanal performance, but there are cases where faults are obvious and numerous. There is little excuse for any but occasional lapses as recording now forms a considerable part of the work of the technical staff' of a large broadcasting service. A variety of methods and processes are available and with proper equipment plus full co-operation of the programme suppliers, by way

of repetition of the item, if necessary, there should be no trouble. The most widely used system is what is known as.direct disc recording, in which the record is cut upon a disc of suitable material and with little or no subsequent processing, is ready for reproduction. There are a number of modern systems of this type in which good results can be easily obtained for as many as 40 or 50 reproductions. In most of these systems a plain disc is rotated at a constant speed, and a cutter is caused to cut a spiral groove, the sound being recorded in the form of lateral variations, the • closeness and depth of which depends upon the frequency and intensity of the sound. In this system are a number of inherent difficulties. For example, the material must not be so hard that the cutter cannot faithfully imprint what is delivered to it, nor so soft that what is placed there by the j cutter is easily worn off by the needle | of the pick-up device. The widths of the grooves must not be so great or : their spacing so close that the indenta- j tions of one almost meet the indenta- I tions of the next, or the needle will | break through or. while it is traversing J I onc groove, pick up something that hasi oeen recorded in the next. There are j a number of other troubles, but re-1 search has found the cause in most cases and has provided an effective j cure. The necessity for accuracy and' j care and in making and handling re- j | Col 'ds may be appreciated by considering the following figures. A 12in record ! for example, has a groove length of I more than 6001't. The groove is about j six-thousandths of an inch wide, and j less than half as deep. The needle ; passes over the groove at about 240ft! 1 per minute and at about 90ft per min- j ute at the end. With only a light pick up the actual pressure at the point of! contact of the needle when it is new is about 12 tons per square inch. This i is H he avy load, and must cause heavy j i weai * ol Ihe record or needle', or both. ; j Careful choice of materials and close! j attention to every detail of the record-j jing mechanisms and circuits are obj viously necessary. Mainly for the rea- j I son that il Provides a quick result and! ; docs not require reproducing equip-! | mint other than that used for ordinary! j records the disc system is the most! 'Widely used, but there are a number of! j other schemes. There is the sound-on- \ ! film systems, such as is used in talking j j pictures which. however, requires' somewhat elaborate recording, developing. and reproducing arrangements., ' Another scheme is that in which the sound is magnetically recorded on a! J steel wire or tape. This also requires*

special equipment, but the scheme has been in use for nearly 40 years and still has its adherents. Another more recently developed arrangement is that in which an opaque film in the form of a strip is moved past a cutter so that more or less of the opaque part is removed in accordance with the nature of the sound. It is reproduced in the same way as ordinary sound-on-film, but the recording equipment is of a special nature.