THE WIRELESS WORLD

Otago Daily Times, Issue 22325, 27 July 1934, Page 14

THE WIRELESS WORLD

NEWS AND NOTES

By Magna Vox.

Items of local v interest are_ invited by "Magna Vox" for publication in this column. It is necessary that such matter should reach this office by Tuesday t»f each week for insertion on the following Friday. 2BL, Sydney.—Bss K.C., 353 metres. 2FC, Sydney.—66s K.C., 422 metres. 3AR, Melbourne.—62o K.C., 492 metres 3LO Melbourne. —830 K.C., 371 metros. SCL, Adelaide.—73o K.C., 395 metres. 4QG, Brisbane.—76o K.C., SBS metres. IYA, Auckland.—6so K.C., 461.3 metres. 2YA, Wellington.—s7o K.C., 526 metres. 3YA, Christchurch. —720 K.C., 416.4 metres. 4YA Dunedin.—79o K.C.. 370,5 metres. 4YO, Dunedin.—ll4o K.C., 261 metres. ANSWERS TO CORRESPONDENTS. " D.C.,” Wendonside.—l am afraid I know nothing of the English set you mention, except what I have read in catalogues. Situated as you are, however, 1 should not think it would suit your conditions. The five-valve battery-powered should give you as good reception as you could wish for, as it is probably one of the best makes on the market to-day. You will, of course, require a good aerial. “Five-valve," Eanfurly.— (1) I should advise you to fit a resilient mounting for the condensers. If it happens only when relatively loud signals are being received, it is probably due to mechanical vibration of the plates of the condensers. (2) Try Messrs Kempthorne, Prosser, Ltd., Stafford street. (3) About 25s to 30s. (4) This is a rather large order, as publication of the list you require would run into about half a page. There are several books on sale at an extremely reasonable sum which will give you the information. R. F. T-, Roslyn.— (1) I should not think you need worry. All possibility of trouble will be removed so long as your aerial is installed properly. Unless the site is exposed, there is little likelihood of the tree being struck, and, in any case, a pole would be equally. vulnerable. (2) It appeared in tbe “ Wireless World ” column published on June 1. (3) So far as I can ascertain there is no agency in Dunedin for the set.

REBROADCASTS OF RUGBY TESTS. Three of the matches to be played by the All Blacks on their forthcoming tour of Australia will be rebroadcast by the New Zealand national stations. The first one to be heard from the Dominion stations will be that against New South Wales at Sydney on August 4—the second match of the tour. The two test matches at Sydney on August 11 and August 25 will also be rcbroadcast in New Zealand. NEW IYA STATION. In spite of the delays caused by fain, good progress is now being made with the erection of the new studio premises for IYA at the top of Shortland street, Auckland. Three storeys have practically been completed, .and portion of the lop floor has been put in, leaving the top storey to be erected. Plumbers and electricians are hard at work in the lower storeys doing their share of the job,* A wooden tower about 60ft in height on the front of the building is a prominent feature of the construction operations. The tower is used to distribute mixed concrete by means of a movable chute to wherever the material is required. Work on the building to house the transmitter to be installed on a site near Henderson is also going ahead well, and it is expected the new IYA station will be on the air by the end of the year. With a power of 10 kilowatts, which is 20 times that of the present IYA, four times that of the new 3YA, arid double that of the new transmitter will be as powerful as any Australian station and double the strength of 2FC and 2BL, Sydney, and 3LO and 3AR, Melbourne. BROADCAST TO BYRD EXPEDITION. Special messages to the 56 members of the Byrd Antarctic Expedition are to be transmitted from W2XAF, Schenectady, at 4.30 and 5 a.m. (G.M.T.) on 31.48 metres on the mornings of July 30 (Monday next), August 13, August 27, September 10 and 24. SMALL BUT EFFICIENT. Situated in far-away Peru, the little amateur station OAJ.B, the transmitter ct which is shown in the accompanying illustration, lias been picked up by several local listeners, notably Mr ,E. Anderson, of Caversham, who recently tuned in to the stranger at noon on no fewer than five successive days. OAIB is owned and operated by Mr J. L, Stauft, of Negritos, Peru, which is only 21deg from the equator. I'lie entire speech equipment, which was designed and built by Mr Stauft, is supplied from a 400 watt, 800 volt power supply using 806 rectifiers and a separate filter system to each stage. All power transformers have auto voltage regulating ti ansformers, 220 volt, 25 cycle primaries, and are immersed in .oil.

WAS IT AN ACCIDENT? Franco is blaming American radio engineers for a farcical incident early last month, when M. Louis Barthou’s radio talk to the United States in connection with the Lafayette centenary was suddenly interrupted by the words, “ Won t you kiss me, Lucicu? ” Astonished listeners in America had been suddenly switched through to a relay of “ La Petite Chocolatiere," by Lille PTT. The transmission went out from the French colonial station at Pontoise, and it was at first alleged that the contretemps was due to carelessness at the short-wave station. The French Posmnster-gcnerat now explains that a temporary break in transmission was caused by a valve failure. Before the trouble could be rectified the impulsive engineers in America had switched over to the alternative short-wave transmitter at Pontoise, which was broadcasting the comedy programme. This explanation follows allegations that the “ accident ” was planned. A DIMINUTIVE MICROPHONE. An inconspicuous little microphone, no larger than a match box, weighing onlythree ounces, and designed to be fastened to the coat lapel of a public speaker or entertainer was the subject of a joint technical paper delivered by Dr Harry F. Olsen and Richard W. Carlisle, research engineers of the RCA Victor Company, before the Institute of Radio Engineers, which was held at the Benjamin Franklin Hotel in Philadelphia. The remarkable little device was worn by the Camden engineer, who delivered the paper as a practical demonstration of the application of the new microphone, and it earned the voice of the speaker through an amplifying system to all parts of the large meeting room with extraordinary clarity. The outstanding features of the new lapel microphone are that it does not pick n_p mechanical vibration from the speaker's chest or from body movements, and it permits the speaker to move round freely without causing any appreciable change in the intensity or quality of bis voice. Another advantage is that the audience's view of the speaker is unobstructed by bulkier apparatus. The new microphone is expected to find a useful application not only for public speaking and broadcasting, but also for sound newsreel work. The new lapel microphone employs the velocity principle of operation. A thin aluminium ribbon is suspended in a mag-

netic field between two poles, and it is operated by the varying pressure on the ribbon resulting from the impact or velocity .of the human voice. Advantage is taken in the design of the fact that this type of microphone is equally sensitive front and back, and when in use it is so arranged that the optimum sensitivity lies in the direction of the mouth when the speaker’s head is turned to either side rway from the microphone. Provision is also made to compensate for diffraction of the voice around the head. A high degree of fidelity in reproducing the voice ip assured by the ability of the mechanism effectively to icproduce tones from 80 to 7000 cycles uniformly. TECHNICAL TERMS. In the course of an address to the Institute of Radio Engineers (Australia) Mr E. T. Fisk, the president of that body, drew attention to the slackness that often exists in the application of names and terras in some branches of engineering. In a rapidly developing art, said Mr Fisk, many new problems arise, one of which is the difficulty of supplying generally accepted terms for the apparatus and processes used. In radio engineering, for instance, there is the danger of the growing up of a colloquialism and looseness of expression which results in the application of semi-technical terms which are almost absurd. Mr Fisk said that there were many ways in which the institution could assist in the development of radio, and one of them was that it could do something to maintain ' a purity of description and so steer radio engineering clear of errors of this type. In wireless or radio, whichever one may prefer to call it, there has always been a chaos of technical terms, in which respect New Zealand is probably in u more unfortunate position than other countries, because here there is the dual effect of British and American influences. In the general term for this system of communication by means of ether waves there is a choice. Thirty-five years ago the word “wireless” was applied, and for many years it was the standard term, but it was generally in association with “ telegraphy.” This is brought out in the names of some of the older, operating companies, for example, Marconi's Wireless Telegraph Company, Ltd., and the French company, which includes in its title the words “telegraphic sans fils.” In the Old World the word “wireless” is still practcally the standard term. In the United States, however, the word “ radio ” has been adopted, and has received universal application, as, for instance, in the name of the Radio Corporation of America and in its use with receiving sets which are often known simply as “radios.” The parts and processes employed in a receiver in the majority of cases have at least two names, for example, the signal collecting means may be “antenna” or “aerial,” am! if it is of the type consisting of a number of turns of wire on a relatively small Structure the terms “loop” or “frame” may be equally well used to qualify it. A receiver may bo “ earthed ” or “ grounded. ’ In British communities there is the , “ valve,” which in America is known ns a “ tube.” In this instance it is difficult ;to select the right term. The forerunner of the present-day component, that is, the device first used by Fleming, was un- ; doubtedly a valve in that it acted as an ! arrangement to allow current to flow in one direction only, a function which today is really only solely performed by cer- ; tain types of detectors and the rectifier i used in sets operated from alternating i current power supplies. The term tube is an abbreviation of “ vacuum tube, ’ ! which is the general expression for a I certain type of appliance which includes i X-ray tubes and Neon lights and many other arrangements. In France this component is known ns n lamp except when it is used as a rectifier, when it becomes a valve. The list of duplications could bo extended indefinitely. At one time among those who had to deal with receivers there was a multitude of terms, most of which ended with -dyne, applied to circuits, (lie majority of which wore variations of one another. To-day there ;s, comparatively, simplicity, and, excluding the fairly wide range of trade names employed, a set is generally described as a set of so many valves, it being assumed that if it is of modern design it is what most of us are pleased to call a “ superhet.,” or oven a “super.” In this term there is a most excellent example of the tendency to abbreviate. Supersonic heterodyne, the proper term, has practically disappeared from use. And so the process goes on, prefixes and suffixes are clipped off; new words are formed in various ways, such I as by the initials and the application of I nicknames, and the English language is I extended, sometimes strengthened and sometimes weakened, hut still extended. I The process is inevitable, but there arc , ways of doing it. There is no reasonable excuse for mutilating a satisfactory word such as “transformer” into “trannio.” a type of verbal contortion which is rather popular. If Mr Fisk’s plea can put a slop to this sort of thing, it has been •' well made.