RADIO

Southland Times, Issue 20618, 17 October 1928, Page 14

RADIO

UNDER WATER RADIO

VAGARIES OF ETHER. Underwater communications by radio, according to a cable is now possible between submarines and signals were sent over a distance of two miles. In thes days of spectacular long-distance transmissions, this little interchange cf messages may sound rather tame, but apart from representing an important technical advance—although underwater wireless is not altogether new—it demonstrates the wonderful adaptability of radio. Signals have oeen received in some of the deepest mines, sent from aeroplanes flying at great heights, and have been made to traverse every part of the globe. And now the ocean evidenly offers new difficulties. When man harnessed the ether he brought to his service one of the most powerful, and least understood forces that he has ever etumbled upon. Without ether, radio or light or heat would not be possible. It provides the conductin gmedium for these factors just as air provides the path for sound. Water is a good sound conductor, and submarines have made use of this fact by sending and receiving messages with delicate instruments which literally act as the human organs of the voice and ears. This, however, is purely a sound device, and has no relation to wireless The most fascinating attribute of ether is the fact that it pervades everything, although “ether leaves” do not pass through all substances with equal readiness. That is why buildings and mountain ranges affect reception to such an extent, being semiopaque, as it were, to the impulses, just as most substances are opaque to light waves, which are exactly the same kind of ether pulsations, only considerably shorter. Wireless waves are subject also to refraction, like light waves, whilst in reflection of the transmission from that upper strat of air—called the Heaviside layer—we have an instance of the laws of reflection in radio. Water is one of the substances in which ether vibrations, of the length used in most radio work, move reluctantly—it is semiopaque to them. This naturally has always rendered under water radio operation difficult, and only by the expenditure of enermous energy on long waves, has it j been possible to get signals to a submerged submarine, and then only over a very limited range. But for practical purposes signals could not be sent from beneath the water, and previously submarines had to rise to the surface to transmit, erecting an aerial which was made collapsible for the purpose. In all probability a method has been found of using short waves for under water work, perhaps with a directional or beam system. In this way far greater distances will be revered with infinitely less power, as they have been in ordinary land working. And although at present this new aspect to radio seems to carry only a warlike significance, it may lead the way to discoveries and inventions having other purposes. Many listeners believe that the only way in which a valve can be put out of action is by a filament burn-out, and that, conversely, so long as it lights it must be in good order. Actually, while the fact of a valve burning, represents definitely the end of its life, this is only one of the things that may happen to it. 2\mongst the “dull emitter - ’ or low consumption valves which are used now ’dmost universally, “loss of emission” is most frequent. One or two types can be rejuvenated by burning the filament, without any plate voltage for some time, but in the majority of valves now made loss of emission means the end of the valve’s useful life just as decidedly as does a burnt-out filament. Sometimes the elements inside become disarranged and touch each other. The most frequent occurrence of this sort is for the filament to sag until it touches the grid, which, of course, puts the valve out of action. In this instance, nothing more serious will happen; but should the plate—which carries the high voltage from the "B” batten-—come into, contact with one of the other electrodes, it is quite possible that all the valves in the set may be burnt out. However, this fortunately seldom happens. On equally n re occasions the vacuum in the valve breaks down, due to a slight leak in the glass, or to foreign gases having been enclosed its manufacture, and the valve loses its efficiency slowly. This, too. is fatal. Care should be taken, in removing a valve from its socket, ♦hat the base and not the valve itself, is grasped and pulled or twisted. as the case m iv be. Otherwise the base may become loose, with every possibility of the leads to the leads coming into contact, causing a short circuit. With a little careful manipulation this can often be adjusted but in the meantime serious damage may have been caused. AT THE GOLDFIELDS The latest discovery of gold in attractive quantities in New Guinea acted as a magnet to draw men from all quarters of the field, and when it was realized that kpeedy communication with the outside world was essential, arrangements were made by Amalgamated Wireless I Australasia), Ltd., for a small spark to be put into operation at Bulolo, and it save valuable service. Later on. however, when the goldfields were properly established and an aeroplane service inaugurated, A.W.A. shipped to Lao a powerful shortwave transmitter and receiver equipment, which was transported by aeroplane to the ®'oldfields, and installed at Bulolo to replace the first set installed. A similar set was installed at Salamoa, and now- communication is maintained between each of ‘hese stations, and also between them and the powerful coastal radio station of A.W.A. at Bita Paka, Rabaul, whence traffic is repeated to Australia to be forwarded to any part of the world. DEFECTIVE TRANSFORMERS Although great improvements have been made recently in the construction and electrical trength of radio frequency amplifying transformers, the necessarily fine windings in these components constitute an unavoidable weak point in every wireless set, and transformer breakdowns continue to occur as frequently as most component failures (writes a Melbourne radio correspondent.) The break in a transformer winding is not always sudden and complete —in fact, it is more often spread over some days or week, and in its early stages it is often very difficult to detect. A complete break, unless it is in one of the secondary windings near the. “filament” end of the winding, results in a practically complete failure of signals. In many cases when a complete break occurs near the “filament” end of the secondary winding the diminution in signal intensity is frequently relatively small. Whenever it is suspected that a complete transformer breakdown has occurred both windings of each transformer in the set should be tested for electrical continuity. This test is made with a battery—a single dry cell or a 4| volt “C” battery will do well—and a pair of telephones. One terminal of the battery is connected to one cord tip on the telephones and the other cord tip of the telephone, and the other battery terminal are then connected to the two terminals of the transformer winding. If a sharp click is heard on the making and breaking of contact it can generally be taken that the winding is sound. A very weak click, on the other hand, indicates that the transformer winding is broken. Faults which develop gradually are less easy to diagnose and more difficult to detect. The usual symptom is an erratic scratching or “ f \ying” sound in the speaker or telephones when the set is in use. This noise resembles ‘he sound made by a loose contact in almost any part of the set or a

defective high-tension battery, and it is frequently attributed to one of these two sources instead of to the transformer. The continuity test described above will usually reveal the faulty winding. Instead of being connected *«, and disconnected from, the winding, as >n cases where a complete break is suspected, the battery and telephones should be left permanently connected to the transformer. The fault will then reveal itself by a slight scratching noise in the telephones. In making this test care must be taken *o see that all connections between the battery, telephones and transformer, are carefully and tightly made. A defective connection will produce the same noise as a broken winding and lead tG a false conclusion. Short of rewinding the transformer, which is a task beyond the average listener, there is no really satisfactory remedy for a broken transformer winding. borne listeners have applied with a measure of success the “killor cure” treatment of momentarily applying a high-tension battery to the detective winding. Ihis process sometimes creates across the break in the winding a small electric arc, which is sufficiently hot to fuse the broken ends to : gether. More tften it will have no effect at all, or else merely aggravate the fault, and whether successful or not it is not conducive to long life in the high-tension battery used, most satisfactory method of restoring the receiver to order is to replace the damaged transformer. AN INTERESTING “PICK-UP” An interesting patent has been issued by the Patent Office of the United States of America for a new form of electrical “pick up” for reproducing gramophone records electrically. Unlike most forms of electrical “pick ups,” the device is very simple, and if it will give *ke results which are claimed for it it should greatly facilitate the combination of a gramophone with a wireless receiver. In the “Pick-ups,” which are being widely used the needle holder operating on the record is attached to a light coil of wire held in an intense magnetic field. As the needle causes this coil to vibrate its slight movement in the magnetic field sets up very feeble ilectric current in it. These currents are then suitably amplified and re produced on a wireless speaker. The device is very effective, and in most cases will give strikingly faithful reproduction from records, especially if they have been recorded by the new electrical process. The new “pick-up” device is even more simple than this. It consists of a needle which is carried in a holder insulated from the rest of the gramophone mechanism. The holder is constructed to allow the needle to move over 6e record in the ordinary way, but to keep it in contact with the record surface lightly as possible. Attached to the needle is a wire which connects it with the grid of the first valve in the amplifier. 'Rhe manner in which the device operates is not definitely known. The patentee, however, suggests that the friction between record surface and the needle generates electricity in much the same way as the old frictional electric machines do. This electricity, conveyed to the grid of the valve, is then amplified and operates the speaker. Using a single valve as an amplifier, it is possible to reproduce the music from the gramophone record with it. Using only one valve, however, the music is very faint, and it seems likely that before the device will give satisfactory results it will be necessary to incorporate in it some means of applying a suitable working bias the grid of the pick-up valve through a suitable resistance. RADIO BROADCAST. AUSTRALIA AND NEW ZEALAND, PROGRAMMES FOR TO-DAY. The following programmes will be broadcast from the principal Australian and New Zealand broadcasting stations to-day:— IYA AUCKLAND (333 METRES). 3 p.m.: Studio items. 4.0: Literary selection by the Announcer. 4.8: Studio items. 4.25: Sports results. 4.30: Close down. 6.0: Children’s session. 7.15: Talk on “Oil Crudes and Specifications,’’ by Gargoyle. 8.0: Chimes. 8.1: Relay of concert by the Auckland Municipal Band —Military Band selections, concluding, with the following records:—Baritone solo—Fraser Gauge, “Slumber on. My Little Gipsy Sweetheart”. Piccolo duet—Jean and Pierre Gennin, “Rippling Streams". Vocal chorus —Columbia Gem Chorus, “No, No, Nanette" Part 1. Foxtrot—Orchestra, ‘ Last Night I Dreamed You Kissed Me”. Grand organ solo—G. T. Pattman, “Jeannette”. - Vocal chorus—Columbia Vocal Gem chorus, “No, No, Nanette” Part 2. God Save the King. 2YA WELLINGTON—SiIent. 3YA CHRISTCHURCH (306 METRES). 3 p.m.: Studio items. 4.30: Close down. 6.0: Children's session. 7.15: Addington stock market reports. 7.30: News session. 8.0: Chimes. 8.1: Relay of orchestral overture from Strand Theatre String Quartet. 8.6: Vocal quartette—Dulcet Quartet, “Moonlight”. Baritone solo—Mr A. G. Thompson, “Sweet, Sweet Lady”. 8.22: Orchestral—Columbia Symphony Orchestra, “March of the Bojaren”. 8.26: Recital —Rev. B. Dudley, F.R.A.S., “Mrs Beads After Shopping". 8.31: Vocal duel —Dulcet Duo, “I Wish to Thine My Quivering Lyre”. 8.35: Instrumental trio—Christchurch Broadcasting Trio, “Presto”. 8.43: Chorus —London Hippodrome Chorus, “Hit the Deck,” Vocal Medley Part 1. 8.48: Lecture —Rev. B. Dudley, F.R.A.S., “The Theory of the Origin of the Moon”. 9.Off Weather forecast. 9.1: Orchestral selection—State Opera Orchestra, “Tho Barber of Seville”. 9.8: Vocal quartette—Dulcet Quartet, “Good-night, Good-night. Beloved”. 9.12: Pianoforte solos—Miss Aileen Warren, (a) “Ondine 1 ’: (b) "Dream Dances No's 2 and 3”. 9.20: Contralto solos—Miss Nellie Lowe, (a) “One Little Hour”; (b) “The Watchman”. 9.27: Instrumental , trios—Christchurch Broadcasting Trio, (a) “Hymn to the Sun”; (b) “Spanish Dance”. 9.36: Soprano solos—Miss Hilda Hutt, (a) “Elsa's Dream”; (b) “Lift Thine Eyes”. 9.43: Waltz— Jacque Jacob's Ensemble, “Morgen Blatter”. 9.47: Tenor solos —Mr T. G. Rogers, (a) “Soft and Pure” from “Martha''; (6) "Roses”. 9.54: Baritone solos —Mr A. G. Thompson, (a) “The Organ Grinder”; . (b) “Mandy and the Spiders". 9.57: Chorus—London Hippodrome chorus, “Hit the Deck,” Vocal Medley, Part 2. God Save the King. 4YA DUNEDIN (463 METRES). 7 p.m.: Chimes.’ 7.1: Gramophone concert. 7.4 Q: News session—Burnside stock sales report. 8.0: Chimes. 8.1: Relay pt orchestral music' from Octagon Theatre Orchestra under the direction of Monsieur Henri de rose. 8.11: Popular song hits—Miss Jacqueline Burke, (a) “Tickle Toe”; (b) “No, No, Nanette”. 8,17: Novelty pianoforte solo—Mr T. V. Anson, selected. 8.22: Popular song hit—Mr Norman Scurr, "Sunshine”. 8.26: Band selections—Band of H.M. Grenadier Guards, fa)' “Turkish Patrol”; (b) “Smithy in the Woods”. 8.33:, Humorous songs at the piano—Miss Eileen Cooper, (a) “Peter”; '(b) “It’s no Use Feeling Fed-up". 8.39: Relay of orchestral selections from the Octagon Theatre. 8.49: Humorous sketch —Miss Anita Winkel, and Major F. H. Lampen, Selected. 8.59: Weather forecast. 9.2: Humorous Scottish song—Mr Buster Brown, “When I was Twentyone". 9.6: Trombone solos—Mr R. B. Hall, (a) “Elizabeth’s Prayer”; (b) “L'Adieu”. 9.15: Popular sopg—Miss Jacqueline' Burke, “Huckleberry Finn". 9.19: Waltz.—Court Symphony Orchestra, “Destiny Waltz”. 9.23: Popular song hits—Mr Norman Scurr, (a) “Golden Gate”; (b) "Oh, Doris, Where do you Live”. 9.30: Novelty pianoforte solos —Mr T. V. Anson, Selected. 9.36: Humorous song at the piano—Miss Eileen Cooper, "Don't I Wish I Were a Man". 9.40: NoveltyCourt Symphony Orchestra, "In a Monastery Garden”. 9.44: Humorous sketch—Miss Anita Winkel and Major F. H. Lampen, Selected. 9.54: Trombone solo—Mr R. B. Hall, “Flower Song”. 9.59: Xylophone solo—Ruby Starlta, “Minuet”, 10.3: Humorous Scottish songs—Mr Buster Brown, “Ta, Ta. My Bonnie Maggie Darling’; (b) “Just a Wee Deoch and Doris". 10.10: Mar.mba solo— Ruby Starita, "Aloha oe”. 10.14: Close down. 4QG BRISBANE (385 METRES). 9.30 p.m.: Topical chorus. Alf. Featherstone and his orchestra—Rhythmic paraphrase—“ June” ; “Paradise and You”. Feo Todd (elocutionist)— Selected items. Country Women's Association. 9.45: Portion of the entertainment arranged by the Country Women’s Association will be relayed. Alf. Featherstone and his orchestra—Fox-trots—-“Song of India”; Fox-trot —“Broken Moon”. S. Wilcox (baritone)—“Drake Goes West”; “The Bridge”. 10.33: Metropolitan weather forecast. .Movements of lighthouse steamers. Alf. Featherstone and his orchestra—Fox-trot—“Dream of Italy”: Fox-trot—“ Sing, Birdie, Sing”. Mrs R. Beil (soprano)—“My Skylark’s Love”; “Sweet Miss Mary” negro love song. Alf Featherstone and his orchestra—Jazz-waltz—“Ramona.” 11.0: “Tecoma” will give another talk in connection with 4QG's home garden scheme. His subject will be—“A Word on Seedlings and Aspects.” Alf. Featherstone and his orchestra—Fox-trot—-“l'm In Love Again”; Fox-trot—“Humoreskimo” ; Fox-trot-“ High Hat Harry”; “That's My Mammy”. 11.30: An astronomy talk—“A Comet in the Sky”—by Mr A. K. Chapman. Late news; weather news. Alf. Featherstpne and his orchestra in three-quarters of an hour’s - dance music. 12.30: Close down.