Radio Review

Evening Star, Issue 19764, 14 January 1928, Page 17

Radio Review

[By “HENRY.”]

Flashes from Everywhere.

WAITING FOR THE AIRMEN. About the sole topic of conversation on Tuesday night last was about the airmen who commenced a 1,239 mile flight across the Tasman that morning The local station, 4YA, was on the air with the usual studio concert from 8 to 10, but instead of closing down at the appointed hour kept going with gramophone music until 12, waiting for some nows of the intrepid flyers. At 0.40 the station opened up again, but only for a few minutes, as there seemed no hope ol any nows being received for broadcasting purposes. Wellington, on the other hand, kept going until 3 on Wednesday morning. Mr Bali (editor-announcer) was stationed at Trentham and from time to time described the spectacle of thousands and thousands of people waiting anxiously lor the aviators who did not arribo. "Mr Bull described the flare lights stationed at intervals round the landing ground and the bonfires in the centre of the ground. He also stated that thousands of motor cars had their headlights focussed towards the centre ol the field. It was a,, wonderful spectacle, 'he added. During the night 4YA was in constant touch with the Post and Telegraph Department, and the station telephone was kept ringing by inquirers. However, all the news available did not bring the welcome message of the aviators’ arrival. Whether 3Ya and IYa were on the air I do not know, but certainly Dunedin and Wellington did their best to give vis some news. PCJJ AGAIN. According to advice- received through Messrs Turnbull and Jones, Ltd., PCJJ, Eindhoven (Philips Glowiamp Works) was to have taken the air again on Tuesday morning last between 3.30 and 7.30 (New Zealand summertime). The wave-length of the re-erected Holland station was to be the same as previously—namely, 30.2 metres. Has anyone heard this station operating this week? NEW ZEALAND LICENSES. As at December 23 last the number of licenses (receiving, dealers, and transmitting; issued in New Zealand totalled 39,223. Figures show that Wellington’s receiving licenses amounted to 14,105, Auckland’s to 13,321, Canterbury’s to 7,821, and Otago’s to 2,120. A short time ago a special programme was broadcast from IYA to give listeners some idea of the type of entertainment that could bo put on the air when the 40,000 mark was reached.

TRY A CRYSTAL SET. As a keen listener myself I cannot understand why more people are not interested in radio. It is undoubtedly the most economic and one of the most entertaining forms of pastimes that has been given to the world. The biggest argument in radio’s favor is that it is immediately available to the working man of small means, for the sum of no more than £4 will enable him to share in a limited way the joys of his more fortunate fellows who have the money at their disposal to spend on a more expensive radio. The man who buys the more expensive set, of course, has a larger range for securing his entertainment, but nevertheless many enjoyable hours may be passed away with the aid of a crystal set. it is usually recognised that crystal reception provides music in its clearest form. Crystal reception does not mean, as some think, that only one person may listen at a time, for when a highpowered station in your own town is on the air it is possible to obtain good reception using four pairs of ’phones. This has been successfully done at a distance of several miles from 4Y r A.

It must be clearly understood, however, that the aerial is an important component, for a weak aerial will surely bring in weak signals. The higher the aerial is suspended above the ground the louder will be the signals. The length ol tho aerial should not be very great—no more than 70ft. The writer, using a crystal set with a 30ft aerial, was able to hear all the local stations quite well, but upon increasing the height of tho aerial to 56ft the signals were received more than twice as loud as previously. A crystal set is tho most economical kind of receiver, for the initial outlay is practically the only expense, and there are no batteries to be charged and no valves to be replaced. Crystal sets can be purchased at prices- ranging from 10s to about £2, according to size and construction, and the headphones range in price Horn 10s upwards. Only a few shillings would bo required for an aerial pole, while the wire, insulators, guy wires, eic., should not cost more than about ss.

'There is a good service available to the crystal listener in Dunedin. We have a 500-watt station which is on the air on Sundays, Tuesdays, Thursdays, Fridays, and Saturdays from 0 p.ni. (approximately) to 10 o’clock, in addition to two afternoon broadcasts a week. There are also two 50-watt amateur stations which can be heard at certain times when 4YA is silent. The big station broadcast programmes contain the best talent available in Dunedin, while tho amateur stations give programmes consisting mainly of gramophone records. The annual license fee is 30s, but I understand a license can be bought at the present time for 7s 6d. This license will last till the end of March. Station 4YA is on the air about 250 nights a year, and taking the license fee at 30s it can bo said that concerts cost the listener about IJd each; therefore for three halfpence per concert a standard of entertainment is provided equal to the best organised at loading local concerts. Furthermore, the class of programmes broadcast in Dunedin are subject to much favorable comment in northern newspapers.

A SHORT WAVE EXPERIENCE. Perhaps the following, written by B.W. for the ‘Listener In,’ may prove of benefit to some short-wave enthusiasts :

“ I had been all the afternoon building a short wave receiver, and was looking forward to a good night’s reception on the short waves band, hut on connecting up the finished set, 1 was puzzled by the presence of a crackling sound. The 13 battery in use was new, and the storage A battery fully charged. Then began a search which lasted until midnight. The audio frequency transformer was removed, and tested by means of a pair of phones and a battery. A new grid leak was used, the valves tested in another receiver, and the set examined a dozen times for loose connections. Then valve sockets, coils, battery leads, phono cords, phone windings—everything which could he a possible cause of the trouble, were examined, but still the troublesome crackling noise persisted. “It was late in the evening by this time, so I decided to defer further search until the morrow. It then struck mo that the aerial might be at fault, but when used with a broadcast receiver, it gave quite good results. Finally all guy wires were examined, insulators cleaned, aiM the aerial overhauled, but even this failed to solve the problem. It was not till later on that I discovered the source of the troublesome interference. _ A galvanised iron double clothes line runs from beneath the aerial at right angles to it over a low metal roofed shed at the far end. Some wire netting had been dumped on the roof of the shed, and this was making contact off and on between the clothes lino and the metal roof forming quite an efficient counterpoise. The fundamental wave length of the clothes wire would alter as it made contact with the roof, and this in turn affected the wave length of the aerialWho would have thought that the trouble could be due to such? From this it will he seen that an aerial which is to be used for short wave work should be substantially erected) and in the open where it will not be affected by any nearby metal.”

REDUCING STATIC TROUBLE. _ Listeners are again encountering increased interference from atmospherics. This trouble is inseparable from summer and warm weather generally, and it is one of the wireless bogys which science has not yet been able to banish completely (says an exchange). Many theories have been advanced to explain the cause of static, and it is probable that a variety of factors contribute to this annoying interference with wireless communication. Thunder storms undoubtedly play their part, and electrical discharges in tha_ atmosphere are certainly one of the chief causes of the trouble in the summer. An interesting suggestion which has been made to account lor some of the trouble is that it is sometimes caused by meteorites entering the earth’s atmosphere. Meteorites are masses _of material, usually metal, of varying sizes, which wander at high speeds through space. Occasionally—that is, in proportion to the number of these bodies which are free in space—-one will strike the earth’s atmosphere, and the intense heat generated by the friction as it rushes through the upper layers of the atmosphere neats the outer surface of the body to white heat, causing “shooting stars” see a in tho night sky. It is estimated that tens of thousands of these visitors strike tho earth’s atmosphere daily, and the larger ones are believed on occasions to produce some of the static which is heard. Electrical disturbances in Hie sun are also said to cause trouble sometimes. Indeed, mysterious noises which wireless operators once believed to be signals from other planets were later considered to be caused by disturbances in the sun.

SAFEGUARDING THE VALVES. ‘ Safeguarding the Vacuum Tubes ’ was the subject of a little talk given from SCL not so long ago by “Dr Fixit.” In this talk “Dr Fixit ” said : “The base of a vacuum tube fits the corresponding socket in just one way—the correct way. Nevertheless, there is an ever-present danger of connectin batteries or wiring in such a manner that B battery current will be applied to tube filaments, with expensive consequences._ Even a slipping screwdriver or pliers may inadvertently divert B battery current through tube filaments, rendering _ the tubes useless. Hence the exercise of due caution.

Although the interference caused by static cannot bo entirely eliminated from a receiver, its effect can be considerably reduced. The fortunate possessor of a super-heterodyne leceiver or similar super-sensitive set is in the best passible position to combat the nuisance, because he can use a loop aerial for reception. When the loop is pointed directly at the desired station it reduces interference to a minimum, because only the signals coming in one direction will affect it strongly. Next to using a directive loop for reception, the best way to reduce the nuisance caused by static is to reduce signal strength on the set. It is found that for a given intensity ratio between a signal and static the interference which the static causes is least wheii the set is so adjusted that signals are as weak as it is possible to make them without causing discomfort to listeners. Signals can be reduced in a variety of ways. The easiest is to use a plug and jack arrangement, by which one or two valves in the receiver can be taken out of use. If this equipment is not included in the set tho filaments of the valves can be turned down until the signals begin to weaken. Another method which is often used is to employ a very small aerial for reception when static is bad. This arrangement, in addition to giving the desired general strength reduction, appears often to possess the further advantage of being less responsive to static, in i 'portion to the signal, than is a large aerial.

“Always disconnect the batteries when working on the radio receiver. In connecting batteries to the radio receiver, connect the A battery first. Then turn on the rheostats or operate the switch, and note if the filaments light. If they do, the connections are correct, and the other batteries may be connected. If not, check the wiring. This procedure prevents placing the B batteries whore they do not belong, and also detects fault-set wiring before expensive damage can be dime. “In the home-made radio receiver or the receiver being remodelled or repaired, it is well to take no chances ■with burnt-out tubes. To this end, a 40-watt 110-volt lamp should be placed in the B lead. The resistance of the lamp will prevent excessive amperage from passing through the filaments of the vacuum tubes if the B battery should be incorrectly connected. Furthermore. it will detect a short-circuit in the wiring, since the lamp will light up. However, because of its resistance, the lamp should be removed or shorted for normal operation. A still better plan is to place a radiotron UV-877 in the B lead. This radiotrom is a protective lamp designed as a safety valve to prevent damage to vacuum tubes or transformers in the event of incorrect connections or short circuits. It introduces protective high resistance only while abnormal conditions exist, so it may be left in circuit. Certain radiolas are provided with this protective lamp.”

CORRESPONDENCE. “Chips” (St. Kilda). —For £2O a good five-valve set could be built, and this price should include high-grade instruments. If you are desirous of building your own set 1 would recommend either a Roberts'or a Browning-Drake circuit. You _ could, on the other hand, purchase a kit which would include the panel (already drilled). By doing tins your task would be much lighter. Failing the purchase of a kit you would do well to get in touch with someone who would supervise the building of the set. I regret I cannot recommend any special make of set.

*• Henry " will be pleased to answer any questions i through this column relating to the fascinating bobby. Each correspondent must sign his name and address (not necessarily for publication). Newsy items will be welcomed.

HOWLEES IN EOSHN. A Roslyn correspondent writes: “Just a few linos to see if a few words in your column would catch the eye of the squealers up here. 1 have been going to write for weeks now, but thought the owner of the worst offender would learn to work his set by this time. During Carnival Week in Christchurch and ever since he has been howling on 3YA and 2YA. 3YA gets a thrashing every afternoon and evening when 4YA is not going, and even when it is on the air there are a few squeals on 3YA, but not enough to spoil the concert. Ido not think this set is ever below the oscillating point, as you can guess what sort of reception he gets, and yet he is so persistent. I think 1 would have given up long ago, especially when being used to a neutrodyne. 1 start cursing if my short-wave set breaks into oscillation at all alter tuning in.”

USEFUL HINTS. An indoor antenna is more efficient for receiving radio signals than a loop, but the latter has directional properties which make it exceptionally valuable in some locations, if you live in a steel-framed building in which metal lath lias been used on the walls tho efficiency of either a loop or an indoor antenna will be low. The only way to overcome this difficulty is to use an outdoor antenna or else to use at least a live-tube set. But even the most powerful receiver cannot be expected to bring in distant stations on a loop or indoor antenna when tho whole room is practically a metal box. Anyone who has wound special coils knows how hard it is to prevent the wire from becoming soiled by the hands. Besides, the perspiration on most people’s hands is slightly acid, and if any appreciable amount soaks into the insulation the Josses in the coil will be much greater than, if the wire were kept clean and dry. Wind your coils with gloves on your hands. This may be a bit awkward, but tho results will warrant the annoyance. Most of the poorly soldered joints that bother the amateur radio constructor are due to working with an iron that is not hot enough. It must be remembered that the solder on the point of the iron should be hot enough so that the surface of the wire or soldering Jug, which it touches, will he heated to a temperature which will permit the solder to flow on to tho surface of the metal, and not simply stick to it in a pasty mass. One drop of acid from the battery will ruin a phone or loud speaker cord. The acid eats its way into the fabric covering and finally weakens the cord so that it breaks at that point. It would not be so serious if it ruined tho phone cord at once, for a new cord does not cost much. The trouble is that it usually causes sizzling and crackling noises and weak signals for some time before the source of tho poor reception is discovered.

RADIO BRIDES. Radio listeners in Now South Wales who pay attention to the Adelaide station SCL have been considerably interested in that station’s radio bride competition. Of all the girls married recently in South Australia (that is to say, those who nominated for the radio competition) Miss Bishop was held to be the fairest, A total of 31,000 votes were cast, of which tho winner polled over 6,000 (states an exchange). The Maughan Methodist Church was the scone of the marriage ceremony, which was broadcasted by station SOL. The speeches and musical items at the reception were also broadcast, “ Undo Radia,” the announcer, acting as master of ceremonies. There has been a certain amount of discussion as to the propriety of broadcasting a wedding service. Tho Sydney station 2BL radiated one from Palmer Street Presbyterian Church nearly three years ago, but last year, when 3LO, Melbourne, had arranged to do so from an Anglican church the ecclesiastical authorities forbade it, and the wedding was transferred to a Methodist church.

In Sydney recently the wedding of the Mayor of Birkenhead, Auckland, New Zealand, was broadcast, and all his friends listened in. The ceremony was heard quite distinctly.

HERE AND THERE. It is reported that an eight-valve act is to bo installed in the Wellington Hospital. Over two million listeners in Britain are licensed. Radio has been installed in an American prisonThe reallocution of wave lengths in America now brings station WDBM, Chicago, within range of Now Zcalanu listeners. A new radio aerial designed to obviate most or the defects ol :,iie horizontal aiui ball types iuts been perfected by Professor Dinmoro Alter, bead of the department ot astronomy at tho University ol Kansas, 'file new aerial hangs vertically, and consists of an ordinary ground wire siieatned in a Jong copper tube, it is said to eliminate static and to give the tdiarpest possible tuning. Unce or twice lately 2XAF, Schenectady, lias been heard in Dunedin, broadcasting mostly dance numbers, UEN contincs to come in at good strength. The station is exceptionally clear. Dig Brother Bill seems to favor diversions in his eJuJdreiTs sessions irom 4TA, for there was Unde dess with lus mutations on Friday nigiit (January (j), and then Domoadier Jenkins on Tuesday evening, Quite a good idea Dig .brother Bui, and I am sure the children appreciate it. If you have not already done so, do not waste any time in giving your aerial an overhaul while the good weather is here. Iron aerial poles would be none the worse for a fresh coat of paint, and wooden masts should be examined, and all cracks carefully filled with putty, A coating of white paint will give the mast a smart finish. Have a look over al the guy wires and make sure they are in a condition to hold over the winter. Have not devoted much time to the Australians during the past week, but when I did tune them in 1 found always a fair number of Oswalds lurking about.

‘ NEW ZEALAND RADIO.’ The usual amount of instructive reading is contained in the latest issue of ‘ New Zealand Radio,’ which has come to hand. A page of hints and tips should be helpful to the home constructor, and an article on a portable aerial explains in full how to build the aerial for both indoor and outdoor use. Another page is devoted to short-wave talk, while other matter is given a prominent place. Illustrations accompany the articles.