THE WIRELESS WORLD

Otago Daily Times, Issue 21602, 24 March 1932, Page 2

THE WIRELESS WORLD

By Maqna Vox,

NEWS AND NOTES

Items of local interest are invited by “ Magna Vox" for publication in this column. It is necessary that such matter should reach this office by Tuesday of each week for insertion on the following Friday.

2BL, Sydney.—Bs6 K.C., 853 metres. 2FG, Sydney.—66s K.G., 422 metres. 3AR. Melbourne.—62o K.G.. 484 metres. 3LO. Melbourne.—B3o K.C., 371 metres. SCL, Adelaide.—73o K.C„ 595 metres. 4QG, Brisbane.—76o K.C., 885 metres. IYA, Auckland.—B7o K.C., 333 metres. Every day except Monday. 2YA Wellington.—72o K. 0., 420 metres Every day except Wednesday. 3YA, Christchurch,—9Bo K.C.. 306 metres. Every day except Tuesday. 4 YA. Dunedin.—6so K.C., 463 metres Every day except Thursday. 4ZM, Dunedin,—loßo K.C., 277.8- metres - Tuesdays and Saturdays. 4ZO, Dunedin.—loßo 11. C., 277.8 metres Monday and Friday, 4ZB, Dunedin.—loßo K.C.,, 277.8 metres. Wednesday. Thursday, and Sunday morning,

ANSWERS TO CORRESPONDENTS. “ Curious,” Palmerston. —Next week. “ Interested,” Oamaru.—l am afraid your set will not be able to_ bring' in the station with an indoor aerial. Even with a good outdoor aerial, reception would be next to impossible excepting under exceptionally favourable conditions. “ Puzzled,” Dunedin. —Your _ earth is unsuitable. Try driving the pipe into a damp spot in the garden, or if no spot is sufficiently damp, remove it to another situation and pour a couple of buckets of water around it every day or so.

“ Condenser,” Kurow.—No; they would be more or less satisfactory without the Earalleled condenser for the short wave, ut if you use the paralleled condenser for broadcast, you would find that the band would not be covered adequately. You would still have a residual capacity of .0002, whereas, if the condenser were acting normally, you would have less than .00005. This, of course, would prevent your covering the band.

A, R., Tuatapere.— (1) No one in Dunedin appears to stock what you require, but I will make further inquiries and let you know as soon as possible. (2) and (3) Yes.

ADJUSTING TRIMMING CONDENSER. The trimming condenser , of a receiver with, ganged tuning should always be set at the lowest possible capacity value; otherwise, the tuning range of the receiver will be restricted to an unnecessary extent. It is often convenient to make the initial adjustment more or less at random, and, when everything else is working properly, to return to the trimmers, reducing the capacity of each of them slightly in steps, and “ reganging ” at each position. The reason for this progressive method is that it is possible to reduce capacity to too great an extent, with the result that one, or perhaps even more, of the circuits is not correctly tuned. As a rule, itfis hardly safe to assume that matching of the circuits is perfect if any one of the trimmers is at its maximum or miniuraum setting.

A NOVEL DEPARTURE. The announcement that the Broadcasting Board intends to take a plebiscite on the question of hours and _ programmes appears to indicate that majority rule is to apply in future (says the Timaru Herald). That may or may not be a good thing, as it may result in the majority of listeners getting what they think they want instead of what is best for them. One advantage of the poll will be that only licensees will be entitled to vote, and mass propaganda by irresponsible listeners will not in this occasion count for much. There is an obligation resting with every licensee who desires to see a good standard maintained to register his vote. It will not cost even a 2d stamp. IMPROVEMENT IN BEAM. Amalgamated Wireless (Australasia), Ltd., reports that the average operating speed of the Beam Wireless System between Australia and England has been increased from about 200 words a minute to 250 or even 300. This improvement is due to the _ installation of a newly perfected aerial and reflector system, and the speed of the beam is more than ever in excess of the speed with which the most modern mechanical apparatus can transmit or receive. The company’s research engineers are now concentrating upon devising higher speed mechanical apparatus. The aerial system at the A.W.A. transmitting and receiving centres of Ballan and Rockbank, Victoria, are a complicated network. The masts (three in - number) are 650 ft apart, the entire network occupying a length _of 1300 ft. Each aerial and its respective reflector are parallel throughout their entire length. For each station there are two aerial systems and one common reflector system. This method is employed so that at appropriate times of the day signals can be transmitted by either the long or short route to England, and the aerials are so arranged that signals are most intense on the Great Circle bearing. Ballan and Rockbank were equipped with the most modern form of beam aerial and reflector system known at the' time of the installation six and a-half years ago. Since the completion of the station continual research has been in progress both bv Amalgamated Wireless engineers and by the technicians of collaborating companies abroad. The result is this new aerial design which, with the same power input, gives greater power to the beam and also increased concentration of radiation along the directed paths. With the old system each unit of the aerial was divided into three tiers, the tiers being connected by coils possessing characteristics suitable for correct radiation. Thus each tier of each aerial unit contributed to the radiation, but the coils were inactive so far as radiation was concerned. In the new system, an intricate method of overlapping gives a continuous length of wire at the points previously occupied by the coils, full radiation over the entire height being so obtained. The new system means that not only is the capacity of the beam circuits greatly increased, but also the period of high speed communication. In other words, a far greater volume of traffic can now be transmitted over the , beam circuits in a given time, affording a faster and better service to beam users. The forming and suspending of the new aerial system was carried out entirely by the technical staff of Amalgamated Wireless. The re-arrangement occupied a period of six weeks, during which there was no interruption to the service.

THE PLEBISCITES. The voting paper which is to be issued to licensees next month submits the following questions:— Do you prefer entertainment by (1) local artists, or (2) recordings? Do you use (1) crystal, or (2) valves? (How many?) To which New Zealand station do you listen most? If the broadcasting hours were 10 a.m. to 11 p.m., at what times would your set normally be in use? Indicate your preference for the folI lowing sessions, and indicate whether you ■ consider the length of the respective [ sessions should be increased, decreased, or , remain unaltered: Religious services; children’s session; news and market report; evening concert; running description of sports; dance session; dinner session. Indicate order of preference for the following classes of entertainment during evenings: Hawaiian music; elocutionary items (serious and dramatic); elocutionary items (light and humorous); short plays and sketches; talks (educative and . informative); band music; light orches- , tral items; classical and chamber music; opera and oratorio; whole-evening plays; humorous songs and monologues; comic opera and musical comedy items (vocal); concerts by musical societies and choirs; vocal solos, duets, trios, etc;; talks (sporting and topical); instrumental solos, duets, trios; quartets; community singing. INDOOR AERIALS. The best type of indoor aerial is that which is obtained by running several short wires from end to end of the room in fan shape—the wires being joined together to'a common down-lead, to which they should be carefully soldered. One mistake often made with indoor aerials is to fix the down-lead so that it follows each bend of the wall’s contour. My advice with respect to this is that where the down-lead is run round a part of the room it ia better that it should run round the picture-moulding rather than round

the wainscoting. Another pood type of indoor aerial can bo secured by elingiug a length of No. 18 double cotton-covered wire round three sides of the room, suspension being obtained by small insulators attached to pieces of cord. This aerial should be twelve inches from the walls and twelve inches below the ceiling. Another very convenient type of indoor aerial can be used in lofty buildings which have a staircase wall; all that has to be done here is to hang a single vertical wire down the well. Some readers may wish to indulge their constructional faculty by inventing methods of hiding indoor aerials. One method, for instance, is to secrete the wires behind a picture, assuming that the picture is about three feet square. The front of the picture will, of course, be as usual, but at the back there is fixed a metal frame, made, for instance, with bedstead laths. From one end to the other of this metal square 70ft of No. 24 thin copper wire can be latticed in zigzag form. It does not matter that the wires touch, as this is a mass capacity aerial. The down-lead hanging from the back of the picture can lie made less unsightly by the use of coloured flex, and the picture should be hung immediately above the_ set if possible. Another novel type of indoor aerial is the lampshade type. This consists of a wire framework approximately 20in across and 12in in depth which is wound with about 33ft of wire insulated from the wire of the framework. In fixing the aerial, follow this excellent maxim: “ Bring the set to the aerial, not the aerial to the - set.” In other words, the lead-in from the aerial to the set should go via the shortest possible route. The farther the wire is run along walls, the greater the loss of energy incurred thereby- I have in this article studiously refrained from dealing with the question of erring methods, because that is a subject that requires more space than i have left. It should be stated most emphatically that the aerial is of prime importance to good reception, and no amount of trouble can be too great to ensure that the aerial system is giving 100 per cent, efficiency of service. The best set purchasable becomes the worst set if it is operated from a defective aerial. Therefore, having explained some of the most vital points in fixing an aerial, I want to conclude by saying that once it is fixed it is not finished _ with. There should be a periodic inspection or the masts of the aerial, as well as the wires and also the lead-in points. Much of the defective reception of programmes is traceable to the fact that the aerial system has not been kept in good condition.