RADIO AJdQ ITS jAND ITS RECEIVERS

Sun (Auckland), Volume III, Issue 681, 5 June 1929, Page 16

RADIO AJdQ ITS jAND ITS RECEIVERS

Conducted for THE SUN by

R. F. HAYCOCK.

PROGRESS OF BROAD- j CASTING TALK TO LISTENERS MR. J. BALL AT HAMILTON The inauguration and development up to the present time of the New Zealand broadcasting station was the subject of an interesting and instructive talk at Hamilton last week by Mr. J. Ball, editor-announcer of the company. The company, said Mr. Ball, owed its inauguration to Mr. Wm. Goodfellow, whose primary object was the benefiting of the Waikato farming community. After lengthy negotiations he was prevailed upon to form a company on a national basis. In this he had the whole-hearted cooperation of Mr. Harris. The business involved the limited dividend of but 71 per cent., any profit above this having to go to the improvement of the service. The company had more than fulfilled that service and had built up an efficient staff that was giving three times the length of service called for under the agreement. After the Dunedin station had been completed, said Mr. Ball, they would concentrate upon improving their programmes. A scheme had been submitted to the Government some three months ago, providing for relay stations throughout New Zealand connecting with the big stations. This would mean that in Hamilton and other similar towns crystal sets could be utilised extensively. This scheme had the whole-hearted support of Mr. Owen, whose recent tour of Britain and America had clearly shown that broadcasting in New Zealand was being run on sound lines. One had to travel to other countries to fully appreciate the difficulties that beset such a country as ours. Mr. Ball then briefly explained the many difficulties of broadcasting in New Zealand. The rugged nature of the country was a big factor.

A humorous account of the difficulties entailed in the arrangement of programmes in an endeavour to cater for every type of listener, was given by the speaker.

Mr. Bail advised those who were interested in wireless advancement in Hamilton to bring influence to bear on the Government to further the relay station scheme. In this he had the hearty support of the meeting, which was of the considered opinion that no time should be lost in furthering their claims for a better and more efficient service. BED-TIME STORIES LITTLE FOLKS’ GRATITUDE The national value of children’s radio sessions was briefly touched upon by Mr. J. Ball, editor-announcer of the New Zealand Broadcasting Company, at a meeting of Hamilton radio enthusiasts. Ali “Uncles and Aunts,” said Mr. Ball, gave their services free so that the children throughout New Zealand could gather a wealth of comfort and enjoyment from their efforts. The thousands of appreciative letters that reached these Aunts and Uncles from their little listeners were to their mind ample remuneration for their trouble. The value of such broadcasts could never be fully realised by the public, he added. CORRECTING FADING Squealing from a receiver is in many cases a sort of high-frequency motor-boating, but it rarely happens in well designed circuits —at least, not when reasonably large by-pass condensers are connected across the high tension battery or eliminator. With modern amplifiers capable of reproducing the very lowest notes, the fault may take the form of a slow but periodic swelling and waning of signals, not unlike that experienced with slow fading. In certain cases the amplitude of the slow oscillations may be such as to completely modulate the incoming signals—i.e., it may completely cut out the signal at its lowest amplitude, and more than double its intensity at the crest. If the trouble is only- slight, it is not annoying, and can, in fact, only be detected if “special attention is given to the output. The variations may be increased so as to constitute quite a large amplitude, but again, if this is slow, the effect is not in every case noticeable. It Is Interesting how one may be misled into thinking that the trouble experienced is due to the station fading, whereas it is really due to this slow kind of motor-boating.. “MOTOR-BOATING” The frequency and strength of this effect depends to a certain extent on the h.f. amplifiers, but to a far greaterdegree on the I.f. amplifiers, the greater the amplification employed the greater is its effect. It is this point which causes slow motor-boating to be mistaken for fad mg on distant stations, and many times a DX fiend has been puzzled by a fellow-listener not being troubled with fading, whereas he himself is constantly troubled with this fault. This only applies to feeble motorboating, for violent motor-boating will take place all the time, w-hether the set is tuned or not.

In most cases, however, true fading is not so regular as motor-boating, and its successive periods are of equal duration. If, therefore, you are troubled with an apparently unexplainable variation in signal strength, try some large fixed condensers across the high-tension battery or eliminator. If this should fail to remedy the fault, try one of the excellent anti-mobo units now available in the plate circuit of your detector valve. It may in some cases be necessary to add such units in the plate circuits of the i.f. stages also.

AERIALISMS

One o£ tile best preventatives of threshold howl In a short-wave set is to use an output Alter of the L.F. eholte-eondenser type. Never attempt to drive a long thin screw into a three or five-ply basehoard without drilling a hole for it,

or the head Is sure to break off just when you are screwing the last few turns. Wood screws are easily driven into soft wood, but it is always advisable to drill a hole for them if the wood is of the type that is liable to split, or the baseboard is of plywood. When a new set is being assembled have a piece of soap at hand and push the screws into this before attempting to drive them, as this makes a surprising difference to ease of working. If you are suffering from 'a, thin and “reedy” distortion for which you are unable to account, remember that this is often caused by H.F. getting into the Li.F. side. * * * As smooth reaction is absolutely essential to successful short-wave reception it is no earthly use buying short-wave coils for a set which Is troubled with ploppy or fierce reaction. * * * A simple and efficient earth connection can be obtained by forcing into the ground several pieces of iron or other metallic tubing. The lead to the set can be fixed into the top of the pipe by means of solder. This contracts on cooling, and causes a bad connection, so metal which expands on setting, such as “type” metal, should be used, If possible.

RADIO FASHIONS MODERNISING SETS Wireless fashions and fancies change quickly, particularly with regard to cabinets and panel layouts. Consequently, the proud constructor must needs be ever changing the appearance of his set if he wishes to present it to his friends as the latest thing in wireless design. Doubtless there are many people who, having constructed their set, perhaps a year ago, - are extremely satisfied with its performance, but would wish it to present an appearance more in conformity with some of the extremely “de-luxe” models now on view. They do not wish to go to the trouble and expense of altering their circuit and baseboard layouts, but would, perhaps, not be averse to a few refinements which would give their set the 1929 de-luxe appearance. New Panel Wanted For the benefit of such, let us take a look at an average panel for a two or three-valve set, constructed, perhaps, a year ago. In the first place, a new panel will be necessary. Plain black ebonite, while not obsolete, is giving way to rather more elaborate affairs. By studying the sets marketed by well-known firms, the constructor will gain many ideas. A mahogany panel, surrounded by a carved wooden framework, is becoming popular. The idea is not so fearsome as it sounds. Carved beading to form the framework can be bought fairly cheaply, and the constructor with little skill can construct a really elaborate affair. In any case, a mahogany or other fancy finish panel presents a better appearance to most eyes than does one of plain black. The constructor should now plan out his new panel layout, bearing in mind that as little as possible should appear on the panel. If he can confine himself to a switch and two dials, so much the better. Looking at his old set, lie will probably find that it bears several terminals. These should be transferred to the strip at the back of the set. Upon the front of the really up-to-date set there should be no aerial or phone leads to mar the appearance. Out-of-date Rheostats Much has been said concerning rheostats, but, without going into technicalities, it is generally agreed that these are becoming obsolete. If you have two rheostats, take out one, joining the two connections, and replace the other by a simple battery switqji, of which several types are now marketed. If you are using, for example, a four-volt battery for two-volt valves, baseboard resistances can be inserted to give the requisite drop in voltage. We can next turn our attention to the condenser dial or dials. If, as is probable, you have those totally inadequate knobs and 3in. dials, you would do well to consign them to the scrap box. There are on the market several excellent drum drives which can be adapted to standard condensers, and which, while giving an excellent slowmotion drive, add greatly to the appearance of a set. If you do not care to go to the expense of one of these, there are a multitude of slowmotion dials of excellent appearance and performance which will give your set that finishing touch. It is when we come to the handle of the moving coil-holder on a swing-ing-coil reaction set that we strike our first snag. This component cannot, of course, be dispensed with without materially altering the circuit, and it is difficult to make a really neat job by bringing the handle out through the panel. One idea I have actually seen, but do not advocate, consists of bringing out the long extension handle, not through the front, but through the back of the set. The coil holder is reversed and a hole drilled in the back of the set. The handle is pushed through and the knob screwed on. If adjustments to the reaction coil are infrequent the idea may serve, but it is only useful to the enthusiast who demands a, clean panel and who is ready to sacrifice convenience to neatness. By following these instructions the constructor will find that he has transformed entirely the appearance of his set. Further ideas to suit individual sets will, of course, occur to the constructor, but he should bear in mind that the ornamental panel with the minimum of controls is the “dernier eri’” in wireless fashions.

TOP OF THE WORLD ALASKA HEARS AUCKLAND OPERA FROM ROME The “‘top of the tcorld” is a heaven for long-distance listeners, ■judging from a letter written by Mrs. Inez E. Moore, of the Alaska Native School at Shungnak, Alaska, to the "Neie York Times.” “It seems strange to every one that we are able to hear so many stations and so widely separated, but our location has much to do with that, also the lack of interference. It is like placing us at the peak of a triangle—and then radio, like so many strings or ribbons stretching out in all directions with none so vastly further away than others,” Mrs. Moore reports. “Germany is very little further from us than Southern California, for they come to us across the pole. Programmes put on in Germany on Tuesday night reach us Monday morning, due to the International date line. Auckland, New Zealand, is our most distant station, which comes to us regularly in the summer months. Thrill From Rome “You see, they have their winter when we have summer, so their broadcasting is stronger at that time. We hear them occasionally now but not so well as in the summer. Lima, Peru, is a long-distance station, but the one which gave us the greatest thrill was IRO of Rome, Italy. On Friday morning after Thanksgiving, 1927, we ate breakfast to some wonderful grand opera music from that station. “One German station taught English last year and for nearly an hour one morning we heard Robinson Crusoe—a few words at a time—given in English, then in German. One station in Japan is teaching English this year. A short time ago we heard the months of the year spoken very slowly in English and then—such jabbering—in Japanese. It will surely be the means of making all nations speak the English language. Days are Mixed Up

“We had a crystal set in 1921-1922 when in Bremerton, Washington, and were as pleased then to be able to hear Seattle as we are now to hear the President give his Thanksgiving proclamation over radio. When we came north in 1922, our friends told us that it would not be possible to find a set which would pick up the nearest broadcasting station (Seattle being over 2,000 miles away). We existed the first two yeax-s—how, I cannot tell- —but when we went out for a month in 1924, we decided to get a set and at least try our luck “When we first set the neuti-odyne up, we thought it was Saturday, and when we turned the set on, these were the first words to come through our horn like a thunderstorm: ‘And now may the Lord be with you.’ It was the closing services of the First Presbyterian Church in San Francisco. We have never had to guess at the day of the week since, for radio keeps us straight even to the hour, for that comes now by telephone clocks direct from Arlington. From that October until the last of the following June, KGO was on the air only three times that we failed to hear them, and so many other stations from far a,nd near. In fact, the fivevalve set was so good we could not separate some of the stations when the reception was at its best. “We then sent for a more selective set, an eight-valve ultradyne. It was more selective, but for volume or distance it could not beat the neutrodyne. We kept both sets and that settled arguments as to whether we would tune in a prize-fight or opera. “Aerials and batteries mean a lot in good and bad reception. We use

storage batteries for both *A’ and ‘B’ current supply. We have for the outside aerial one single 350-foot, No. 12 copper wire, running north and south. We also have a copper tubing inside aerial of about 36 feet next to the ceiling. Some nights we use both of them, sometimes just the outside, sometimes the inside tube, and, then again, cut them both out and with no aerial at all hear Oakland, Seattle, St. Louis, Chicago, and many other large stations. “I do know that no set can mean as much to folks in the States as it does to those so far from home and civilisation as those in Alaska.” GRAMOPHONE REPRODUCERS The electrical gramophone reproducer possesses such technical advantages over the mechanical reproducer that electrical reproduction is rapidly replacing mechanical reproduction in many of the better class talking machines. Owing to the fact that an ordinary gramophone can be fitted with an electrical “pick up,” which will enable the gramophone music to be transferred to and reproduced on a broadcast receiver, many listeners are now converting mechanical gramophones to electrical gramophones, and combining them with their ordinary broadcast sets. One of the problems confronted when this conversion is made is that of providing an effective means of controlling the volume of sound from the gramophone. In cases where multivalve receivers are employed the degree of signal amplification afforded is usually so great that the gramophone music reproduced on the w-ire-less ioud speaker is unpleasantly loud. Some of the “pick ups” sold for fitting to gramophones can be fitted with a volume controlling device, hut the inclusion of this device usually nearly doubles the price of the “pick up.” An easy and effective method of controlling volume without the aid of one of these special devices consists of the adjustment of the gramophone needle In the holder or “chuck,” to which it is fitted on the reproducer. Normally, the needle is inserted into this holder as far as it will reach. If, however, it is inserted only sufficiently far for the set screw in the holder to grip the stem of the needle and hold it tightly, it will be found that the volume of sound will' be greatly reduced.

Conversely, if very loud music is required, the end of the needle stem can be cut off with a pair of strong pliers, so that it can be inserted farther into the holder. By this means the volume of music can be controlled over very wide ranges. This method of volume control can be applied to machines fitted with the ordinary mechanical reproducer, as well as those electrically equipped. A friend who has just returned from the U.S.A. tells me that he learned that thousands of people there have combined radio and gramophone sets costing sums fantastically beyond their means. It’s all done by the instalment system which bulks so largely in American home trading. The only reason many families do not possess an elephant is that they have not been offered an elephant for a dollar down and small weekly payments. An aerial of the inverted L-type is directional toward stations which lie in a direct line with it, looking from the free end of the aerial. toward the lead-in end. Imagine the aerial wire to be an arrow with its head in the lead-in end, then the arrow will point toward the point of the compass to which the aerial is directional. An aerial of the inverted T-type where the lead-in is taken from the centre, is directional anywhere in a straight line with the aerial. Thus, with this type of aerial there are two maximum directional positions.