WIRELESS NEWS

Press, Volume LXVI, Issue 20098, 29 November 1930, Page 9

WIRELESS NEWS

(By "MAX.") The reed typo of headphone and the horn or cone with the same unit were perhaps the next to be developed after the simple horn speaker. In this unit there is a small armature, or piece oi soft iron balanced between the poles of a permanent magnet which is shaped so t'lat the north and south poles are forked to make double end pieces or polos. The armature is pivoted in the centre and carries the coil of fine wire which receives the fluctuating currents from the receiver. When current flows through this coil it magnetises the armature, making one end a south pole and the other a north at one moment, and the next fraction of a second, aa the current reverses, the polaritv of the armature is changed, and this cycle is repeated in tune with the received signals. As each end of the armature is exact!} between a north and south pole of the permanent magnet when there is no current flowing and it is not magnet ised bv speech currents, it is balanced, but when it is magnetised, the end which is north will be drawn by attraction of unlike poles towards the south pole of the permanent, at the same time it is repulsed by the south pole at the other side of it. A similar attraction and repulsion effect goes on at the other end at the same time and acts in tho same direction so far as movement of the armature is concerned.

Tlie strength of the notion depends upon the strength of the varying currents, and when the current reverses on the next half cycle the armature moves in the other direction. The armature is connected by means of a lever system with a diaphragm in the headphone unit or to a large stiff paper cone. One make of reed headphone has a depression in the diaphragm in the shape of an inverted cono and this is attached direct to the nrniat«r». The same faults are apparent in the reed Unit, but not to the same extent as in the type doscribed last week, namely, that there is not an even response to all frequencies and the range of tones covered is not sufficient. Slight distortion also appears. * * There has boen a slight change made in the wave-length of the Auckland station on account of the heterodyning of n carrier wave from another station. The unpleasant reception due to this cause should now have disappeared.

The Loftin-Whito two stage direct coupled amplifier is very useful if applied to any suitable receiver and "Radio Record" has been giving descriptive articles dealing with different combinations which will work well with it. * * The seventh annual Radio World's Fair was held in New York in September and lasted one week. Over 300,000 people visited the exhibition, where nearly two hundred manfacturers of receivers and accessory apparatus displayed their wares. Some 1500 sets worth about £300,000 were attractively shown and covered all types on the market More than a dozen models were equipped with automatic tuning devices Dy means of which any desired station could be tunecf in by merely pressing the correct button. An outstanding feature was the first public showing ot the all electric superhet machines. This type of receiver has been in the background for a year or two, but the development of the A.C. Bcreen grid tubes has enabled manufacturers to design supers which will take advantage of the high amplifying and power delivering properties of these valves as well as the simplicity of operation ot the superhet. * * Almost every manufacturer is using the molten screen grid tube. The use of the A.C. type has passed the experimental stage, and gives greater power than the D.C. prototypes. Valves themselves are more of a uniformity as tho result of improved methods of construction and manufacture as well as testing. * * Besides the true radio exhibits there were others utilising radio principles, and these attracted considerable inter est. Principal among these displays was a complete talking motion picture studio, in which visitors were subjected to actual screen tests. The purpose of the exhibit was to show t'-e close relationship between the sound picture and wireless broadcasting. The chief difference is that a camera is used in pic turo making, the sound equipment being exactly the same. Microphones with speech amplifiers and then a means of converting the electrical impulses into a varying light, which affects a photoI graphic strip on a film to be converted back again to sound when required, is little different from a microphone and amplifiers followed by impressing these electrical impulses upon a carrier wave to be de-modulated at the receiving end and amplified to the required degree. In other words, much of the apparatus used in radio transmission has made possible tho modern talkie picture. Tho above-mentioned exhibition was followed by tho Tenth Annual Radio Exposition, held in Boston. N- » A few months ago a selective crystal set was described in these columns. A new crystal receiver owner close to the King Edward Barracks complained of Morse interference, which proved to bo coming from the Army station, which, by the way, uses only six watts of power input. A selective crystal set was loaned to the complainant, and he was delighted with results, the interference being reduced :to a negligible point, and at the some time he stated that the signals were stronger than those from the simple one in use before. # $ If owners of crystal sets would only go to a little trouble, and experiment with different types of circuits as well as with different crystals, they would have a good deal of fun as well as obtain better results. The necessary parts cost very little these days, and there are always helpers with the required knowledge, who will give advice as to how to go about the work. Of course, there are a few who experiment, but they are in the great minority. # * Those who have used wavotraps on valve receivers have >nly to apply th« same principle in constructing a selective crystal set. If a tuncl circuit is coupled to an aerial coil, and is tuned to some station it will absorb mojt of the energy received by the aerial on that wave-length, and little from others not in tune. Well, a loose coupled crystal receiver is designed along the line of this simple idea. The great majority of crystal sets consist of a slider tuner, and will pick up almost anything on any wave-lengtl. if the station is at all close hi»ndy. Again, the tuning coil itself tunes to about the 80-metre band, and bo is more apt to pick up amateurs on the 75-85 band.

Notes From Far and Near

broadcasting. TO-DAY'S PROGRAMMES. 3YA, CHRISTCHURCH (980 Kilocycles.) recital, 4.25: Sports results. 5.0: Child- £ e " s h° ur . Aunt Pat. 6.0. Dinner session. ! u . News session. 7.30: Sports results.] ®* U: Chimes. Scottish and dance programme 1 by the Caledonian Society's Pipe Band under j I ipe-Major Charles Gibson and assisted by March—Pipe Band, "Dovecote Park" (Braidwood). Slow air—-Pipe Band, ! 'Green Hill* of Tyrol" (Logan). Slow march—Pipe Band, "Bonnie Mary". (Logan). Soloist, Pipe-Major Robertson. 8.7: Talk —- Right Hon. J, Ramsay Mac Donald, "Robert Burns, a Man Amongst Men." 8.15: March —Pipe Band, "The Haughs of Cromdale" (Logan). Soloist, Pipe-Major McLeod. Strathspey— Pipe Band, "Miss Drummond of Perth" (Logan). Reel—Pipe Band, "Tail Toddle'* (Logan). 8.21: Contralto —Mrs I). W Stallard, (a) "Doon the burn, Davie, Love" (Crawford); (b) "Where has Scotlnnd Found Her Fame?'* ft.27: Medley— Debroy Somera Band, "Scottish Medley" (arr. Somers). 8.35: Vocal —John Goss and Cathedral Male Voice Quartet, (a) "Lowlands"; (b) "Highland Laddie" (arr. Taylor Harris). 8.38: Caledonian Pipe Band Quartet, retreat, ''Lochinsido" (Logan;. 8.43: Scottish song and story—Mr c Lockhart, introducing "I Love Ma Jean (Lauder'). 8.49: 'Cello—Lauri Kennedy, "Old Scotch Melody" (arr. Kennedy). 8.53: Baritone—Mr Robert Allison, "Border Ballad" (Cowen). 8.57: March—Caledonian Pipe Band, "McKay's Farewell to the 74th.* Waltz—Caledonian Pipe Band, "Believe Me If All Those Endearing Young Charms (Logan). 9.7: Weather forecast and station notices. 9.9: Band—ll.M. Grenadier Guards, "Scottish March" (traditional). 9.12: Contralto—Mrs D. W. Stallard, "The Auld Scotch Songs" (Leeston). 9.16: Pipe Piper J. Shannahan: March, "Blue (Logan): strathspey, "Braes of (Logan); reel, "The High Road to Linton (Logan). 9.21: Baritone —Mr Robert Allison, (a) "Kirconnel Lea" (Moffat); (b) Wee Hoose 'Mang the Heather" (Lauder). 9.31. Choral—"Famous Forty** "Annie Laurie" (Douglas-Scott). Mezzo-soprano—Mrs Maud Wood, (a) McDonald" (Roecke) ; (b) "Jock o Hazeldean" (Jan Kerr): (c) "Caller Oil (Ja«. Kerr). 9.4 H: Scottish Ronft and story—Mr Jock Lockhart, (a) "When I Meet McKay (lißuder) ; (b) "Just a Wee Dcoch and Doris" (liauder). 0.52: March —Caledonian Pip© Band, "Sweet Maid of Glendaruel (Logan). Waltz —Caledonian Fipe "Sunny Days in Maoriland. Marc!n— Caledonian Pipe Band, "Atholl Highlanders" (W. Rose). 10.2: Dance music until 11 p.m. 3ZC, CHRISTCHURCH. (250 Metres.) ]') a.m.: "Paradise Isle," Dinner Music Ensemble. 30.5: Tested recipes. 10.25: "Trail of Dreams,'* Constance Merinp (j iano); "Will o' the Wisp" and "That's the (World in June," Anna Case (soprano); M Le Cvnge," Herman S&ndby ('cello); "Oh! How I Miss You To-night," Rae Eleanor Ball (vidin), "A Tanto Amor," Mario Laurenti (baritone); "Hungarian Lustpiel," Edieo.i Concert Band. 11 a.m.: "Fate"—Tango de Concert, Music Ensemble; "Crasy Quilt," Constance Moring i.piano); "Synnove'a Song," Anna Case (soprano) ; "Pastcl-Men-uet" (Paradis), Tollefflcn Trio; "Broken Djearns," Rae Eleanor Ball; "Credo," Mario Lrurenti (baritone); "Raymond" overture, Edison Concert Band. 31.30 a.m.: Close down. 2YA, WELLINGTON (720 Kilocycles.) 3 p.m: Chimes. Selected studio items. 3.30 and 4.30: Sporting results to hand. 5.0: Children's session. 6.0: Dinner music session. 7.0: News session, market reports and sports results. 8.0: Chimes. From the Town Hall, relay of the Wellington Commercial Travellers and Warehousemen's Association Male "Voice Choir's last concert of the 1930 season (Conductor, Mr John Bishop). 10.0: Dance programme. IYA, AUCKLAND (900 Kilocycles.) 11.45 a.m.: Relay—Results of Takapuna Jockey Club's meeting, interspersed .with gramophone items from the studio. 5.0 p.m.: Children's session, conducted by Cinderella. C.O: Dinner session. 7.0: News and market reports. 7 40* Talk—Mr O. D. Butter, "Gladioli." 8.0: Chimes. Special Programme in Commemoration of Bt. Andrew's Day. Overture—Debroy Homers Band "Scottish Medley" (arr. Somers). 8.5: Soprano—Miss Beta W. MacCullay, (a) "Robin Adair" (trdtl.); (b) "We'd Better Bide a Wee" (Claribel). 8.11: Selection— String Octet under direction of Mr J. Whitford Waugh, "The Thistle" (Myddieton). 8.21: Scottish Humour (patter and song), Sandy and Mac, (a) "Doughie the Baker"; (b) "Queen Amang the Heather"; (c) "The Wedding o* Sandy McNab" (alt by Lauder). 8.36: March—Auckland and District Highland Pipe Band, "Road to the Isles'* (M«Millon). Hornpipe—Pipe Band, "Black Bear" (Walsh). March—Pipe Rand, "Back of Benachie** (Logan). 8.45: Lecture— Mr A. B. Chnppell—Topical Talk. 9.0: Evening veather forecast and announcements. 9.2: Strin/r Octet. (a) "ITame o* Mine" (Murdoch); (b) "Scotch Poem." 9.9: Ronrano—Miss Reta W. MacCullay, (a) "Jock o' Hazeldean" (Scott); (b) "The Land of the Leal*' (McKensfe). 9.15: March—Pipe Band, "Auchmountnin's Bonnv Glen* * (Balloch). Btrnthspey- "Strunn Robertson" (Robertson). Reel—"Highway to Linton" (Logan). 9.23: Tenor—Mr A. L. Macpherson, "Of a* the Airts" (Burns). 9.27: String Octet, "Scotch Pastorale" (Saenger). Suite—String Octet, "My Native Heath" (Wood). 9.39: Humour—Mr Owen Pritchard, "The Waggle o* the Kilt" fLander). 9.45: Retreat—Pipe Band, "When the Battle is Over" (Brown). March-—Pipe Rind, "Highland Laddie" (Logan). 9 50: 'Cello—Laiiri Kennedy, "Old Scotch Melody** (arr. Kennedy). 9.54: Selection —String Octet, "From the Highlands" (Langey). 10.2: Programme of dance music. 4YA, DUNEDIN (650 Kilocycles.) 3 p.m: Chimes. Selected gramophone items. 4.25: Sporting results. 5.0: Children's hour, conducted by Uncle Sambo. 6.0: Dinner music session. 7.0: News session. 8.0: Relay from 3YA, Christchurch, of vaudeville programme. 10.0: Dance session.

SUNDAY. 3YA, CHRISTCIIURCH. 3 p.m.: Afternoon session—Gramophone recital. 5.30: Children's song service, by children of the Salvation Army. 6.15; Studio chimes. 6.30: Musical recordings from studio. 7.0: Relay of "Salvation Meeting" from the Salvation Army Citadel, Victoria square. Conducted by Adjutant Goffin and Mrs Adjutant Goffin. 8.0 (approx) : Musical recordings from studio. 8.15 (approx.): Relay of programme from 4YA, Dunedin. 2YA, WELLINGTON. 8.0 to 4.30 p.m.: Afternoon session of selected gramo phono records. 6.0; Children's song service, conducted by_ Uncle George, assisted by the Kilbirnio Presby terinn Sunday School Choir. 6.55: Relay of evening service of St. Gerard's Redemptoriat Church. Organ solo, "Melodie" Stojowski (Schott). Rosary, with choral responses. Antiphon, "Alma Redemptoris" Gruber (MS.). Sermon, Rev. Father J Green, C.S.S.R. Hymn, "Out of the Depths," Gouditnel (MS.). Motet, "Panis Angelicus." Casciolini (MS.). Motets, "O Salutaris," (Miller) (MS.). "Tantum Ergo" Clarke (MS.). "Adoremus," Zimmerman (CaryO. Organ solo. "Marche aux Flambeaux," Lefebure-Wely (Schott). Organist. Mr Henry Mount; choirmaster. Mr Frank J. Oakes. 8.15 (approx.) : Studio concert by the Wellington Munieipa l Tramways Band (conductor, Mr E. Franklin), and 2YA artists. Overture—-Band, "Morning, Noon and Night" (Suppe). Soprano—Miss Nora Gray, (n) "From the Land of the Sky Blue Water" (Cadman); (b) "The Lover's Flute" (Cadman). Zonophone Salon Or*

chestra, (a) "The Call of the Angelus (Walton); (b) ''Fairy Tiptoe" (Walton). Baritone—Mr H. Mitchell, * 'Friend o' Mine" (Sanderson). Selection—Band, "Scheherazade," Parts 1 and 2 (from "A Thousand and One Nights") (Rimsky-Korsakoff). Contralto—Miss Jessie Shmith, (a) "If Thou Wert Blind" (Johnson); (b) "Just You" (Sampson). March—The Band, "Twentieth Century" (Ord Hume). Weather report and station notices. Organ—Terence Casey, "Devotion" (Ketelbey). Soprano —Miss Nora Gray, "The Willow" (Goring Thomas). Cornet duet —Bandsman W. Stevenson and J. F.irrell, "Ida and Dot." Baritone —Mr H. Mitchell, (a) "The Lute Player" (Allit sen); (b) "Absent" (Metcalfe). Selection —Band, "Scheherazade," Parts 3 and 4 (from "A Thousand and One Nights ) (Rimskv-Korsakoff). Contralto — Miss Jessie Slimlth, (a) "A Morning Hymn" (Henschel); (b) "A Hundred Moonlit Miles Away" (Tivy). Xylophone with accompaniment—Bandsman J. Michel, The Islander March" (MSS.). Choral—Manse Beauion, M. Bordon and Chorus. Church Scene" (from "Faust") (Gounod). Patrol —Band, "Junsle Drums" (Ketelbey) March —Band, "The Middy" (Alford). IYA, AUCKLAND. 3 p.m.: Afternoon session—Selected studio Items, including literary selection by the Announcer. 6.0: Children's song service, conducted by Uncle Bert. 6.55: Re.ay of Divine service, Auckland Cit*y Mission, fr om the Church of Epiphany. Preacher, Kev. Jasper Cnlder; choirmaster and organist,, Mr John Tait. 830 (approx.): National Military Band, "Ben Hur" (Byng). Baritone —Mr Norman Day, (a) "Border Ballad (Cowen); (b) "Old Barty" (Grant). Instrumental—Studio Trio, ' Nocturne, Op. 148" (Schubert). Vocal duet—Madam 9 Cora Melvin and Mr Norman Day, A P"' Moon •• Violin—Mr J. Whitford Waugh. "Romance" (D'Ambrosio). Choral Don Cossacks Choir, "Evening Bells (arrga. Serge Jaroff). Instrumental —Studio (a) "Melody Pathetique" (Beethoven). lj>» "Scherzo from Trio, Op. 19" Soprano—Madame Cora Melvin, J 8 ) w . Little Coon's Prayer" (Hope); (b) When the Dream is There" (D'Hnrdelot). Studio Trio. "Scherzo, Trio 1, Op. 32 (Arensky) Vocal duet—Madame Cora Melvin and Mr Norman Day, "A May Morning ( e ,• Black Diamond Band, "The Last Good-bje (Moretti). 4YA, DUNEDIN. 8 p.m.: Chimes. Selected gramophone items. 5.30: Children's song somce, conducted by Big Brother Bill. 6-3° - rh j. of evening Church service from ii"t of Otago, Dunedin. Preneher, Rev. • Stevely; organist, Tt. V. E. Gahyay Seiccted recordings from the studio. Na < Symphony Orchestra, "Stradella Piano—Mark Hambourg, "Hungarian . sody" (L»*zt). Baritone- —Peter Daw so i. "Nazareth" (Gounod), "Gesu Bambino. Vienna Philharmonic Orchestra, ,? CI 11 ?**' Noon and Night in Vienna." 8.15: Relay from St. Kilda Band Rotunda of concert bv St. Kilda Band, under direction of Mr Jas. Dixon.