ANTHONY ASQUITH ON BROADCASTING FILMS E IRE Edited by NORMAN EDWARDS Vol. XI. No. 26. FEBRUARY, 1929. My Programme - - By Rosita Forbes The" Neutro- Screen "Three The " Instanto " Two Radio and the Gramophone Supplement etc., etc., etc. MODERN WIRELESS February, 1929 In a recent Cape to Cairo and London car endurance test Mullard Valves were unhesitatingly chosenforthe radio installation in the car. A seven months' journey - over mountains, through rivers, across some of the roughest country in the world-andnotasinglevalve breakage or replacement during the whole journey. Mullard Valves were chosen because experience had proved their relia- bility; this severe test again con- firmedtheirsupremacy. Under the most adverse conditions the travellers were ableto maintain communication and to enjoy the B.B.C. programmes in their lonely camps. Use Mullard Valves in your receiver. Use them for reliability, for strength, for tone, volume and distance. MullardTHE -MASTER-VALVE ADVT. THE MULLARD WIRELESS SERVICE CO., LTDMULLARD HOUSE, DENMARK STREET, LONDON, W.C.2. Arks February, 1929 MODERN WIRELESS CONTENT VOL. XI.No. 26. MODERN WIRELESS. FEBRUARY, 1929. Page Page 161 Editorial . 119 Kalundborg's Companion . .. 163 On the Short Waves . 120 Grid -Circuit Coupling Broadcasting Films - Will it Come to The New Pentodes .. ..165 That? .. How Time Flies in Radio .. 167 The " Neuiro-Screen "Three' 123 A Versatile Meter 169 An H.F. Fault -Finder 129 Short -Wave Schedules 172 Finding Foreigners .. 131 Aerials Abroad .. 173 The " M.W." Tapped Crystal Set 133 Mixing Battery Acid . 176 " 6 L T " Crystal Amplifiers .. 177 B.B.C. Progress in 1923 139 Generating GiganticH.T. 179 Questions Answered .. 142 Sound Connections ..181 The " M.W." " Transportable " Four ..143 My Broadcasting Diary.. ..183 A Detector for Detectives .. ..149 In Our Test Room .. ..187 My Programme .. 151 In Passing ..190 Radio Abroad 154 Radio Notes and News ., ..21? The " Instant° " Two 155 " Safety -First " Radio ..224 Coils for the " World -Wide " Five .. 160 Short -Wave Condensers .. 22f SPECIAL SUPPLEMENT, " RADIO AND THE GRAMOPHONE, PAGES 195-210 As some of the arrangements and specialities described inthis Journal snap be the subject of Letters l'atevf the amateur and trader would be well advised to obtain permission ofthe patentee to use the patents before doing so. Edited by NORMAN EDWARDS. Technical Editor:G. V. DOWDING, Grad.I.E.E. Scientific Adviser :J. H. T. ROBERTS, D.Sc., F.Inst.P. ,, .,11/111 1!:ATL.-INC 1111E01 FOR ANY SETTING ANYWHERE "LION"AMPLION CHASSIS SIMPLY A SPEAKER-a New Amplion devoid of outward show. The works --and nothing but the works. Think what you can do with this New Am -)lion in Chassis form. .. You have, perhaps, a piece of furniture into which this wonderful Speaker will fit ? A corner cup- board, say-an old oak chest-a music case, a book case, a china cabinet .. Or, maybe, you have some particular design in mind and either wish to make a cabinet yourself or have one made to suit your individual taste.. Here, then, is the very thing-an inner Amplion, the essential There is no limit to the many waysinwhich A , plion, plain of appearance, certainly, but with existing furniture can be all that astounding quality of reproduction to utilisedtoaccommodate which the New Arrplion owes its supremacy. the New Amplion Chassis. Here, for instance,isa STANDARD CHASSIS L.1.4 (14" Cone) Heigh,t 17i" 16.0.0 book -caseinwhichthe Width 17e.DePth 81' ... Chassis will fit perfectly. POWER CHASSIS .L:18P "8" Cone): ve. Width 21r DefithHeight 10i" 18.0.0 The complete Cabinet Models in 'he new Amplion range are Or that old chiffonier, used obtainab,e in a wi,e variety of designsat prices ranging from nowadays for storage pur- £9 10 0 t,.£42 0 0. poses? Why not remove the door, fix a neat curtain, and Cat ,logues from all Radio Dealers or from Graham Amplion Limited make a home for Amplion ? LONDON: 25/26,Savile Row, W.1. Works. SLOUGH. 117 MODERN WIRELESS February, 1929 theelody Make It aCLEARER LOUD wit it volunaeValves surprisiug..the Vouget . thewon- Valvespossible Maker. Cossurntaae clear Ntelodycr),stal whiellCossorgiveis house. derful theytoCAI the atelody y ouown,ossor IV enoughoti Set reception. andloudtype *battverwill'improve'Receiver. Etkves any l'itelintprove With A. C. Cosso, Ltd.. Highbury Grove, London, N.S. gail"98= 118 February, 1929 MODERN WIRELESS t , February, 1929. 11 Sets in this Issue-The B.B.C. Publications-" The Listener "-Cost of Programmes-The " Ideas Department." By The EDITOR. Four New Sets with the result that announcements were recently made THE four sets which we describe in this February concerning " The Listener." issue of MODERN WIRELESS have been selected The first issue was published on January 16th. Although froin over a dozen receivers which the Research it was stated by the B.B.C. that " The Listener " con- Department has been experimenting with for sow time cerned itself almost entirely with personalities, subjects past. The " M.W." "Transportable "Fourhasbeen and matter associated with the microphone, and that designed by the Research and Construction Deapartment it would not be inoompetition with other weekly journals, with a view to producing a completely self-contained and that, further, it would make broadcast talks more receiver which can, be moved from room to room with effective, inasmuch as it would tend to strengthen and the minimum of difficulty. widen the market of the printed word, a considerable The " M.W." `°Transportable " Four will bring in many amount of opposition has been created. programmes, and the home-made. loud speaker will be found tobe extremelyefficient.We shouldliketo " The Listener " point out that a striking feature of this set is that it ALTHOUGH it is quite true that under the terms of the has one -dial tuning, although there are no ganged con- B.B.C.'s charter there is nothing to restrictits publishing activities, it is undoubtedly unfair that densers or other complications.Itisaremarkably simple and inexpensive set and we feel sure that itis the B.B.C. should further supplement its activities by the undoubtedly one of the most practical portables ever production of this journal.It must be remembered that designed. the B.B.C. is a Government department and, on moral The " Neutro-Screen " Three is a powerful set specially grounds,itisunwise that such a journal should be designed for short-wave work.It employs a neutralised published, in view of its official " origin." screened -grid valve, giving maximum stability and ampli- Furthermore, it has been alleged that the B.B.C. pays fication.This receiver has been specially designed and no Income Tax, and its primary object in life should be provide. described by our well-known contributor,Mr.C.P. to broadcasting entertainment.Criticismhas Allinson, A.M.I.E.E. already been levelled at the B.B.C.'s efforts to take upon The " Instant° " Two incorporates two simple switches itself the task of educating the public, anditis not with which you may turn from any one to any other of surprising that all those vested interests connected with three stations without referring to the tuning controls publishing and printing should have condemned, in no ofthisefficientlittlealternative -programme receiver. uncertain words, a state of affairs which allows the B.B.C. It is an easy and cheap -to -build set, and the simplicity to produce these publications ad /ibilvm. of its operation needs no stressing.It has been designed As a result of the deputation which conferred with the and described by Mr. L. H. Thomas. Prime Minister, the B.B.C. has agreed not to publish any The " M.W." Tapped Crystal Set is another production morejournals,and,furthermore,torestrict" The of the Research Department.Its outstanding features Listener " in certain definite ways.The improvement of are high selectivity and a gain in volume instead of the actual 'broadcast programmes, rather than the production of more usual loss in sensitivity. journals which are outside their 'e 'itimate scope of activi- ties, will now, it is hoped, occupy the B.B.C.'s attention. The B.B.C. Publications " Daily Mail " has been taking a close interest As the result of a suggestion from Lord Crawfurd's Com- THEinB.B.C.finance,and although certain facts mittee in 1925, inquiries into the possibilities of which the public were not aware of before have broadcasting in relation to Adult Education were come to light, a good deal of thefullstoryhas not recently carried out under the joint auspices of the British yet been told-until our readers turn to the article in this Institution of Adult Education and the B.B.C.In the issueentitled" B.B.C.Finance,"which is based report of the deliberations and findings of the Committee, upon the statements of a most reliable authority. it was recommended that the B.B.C. should publish a The " Daily Mail," however, points out that the Chair- weekly journal, both supplementary and complementary man of the B.B.C., the Earl of Clarendon, receives a salary to its talks and educational broadcasts. This recommenda- of £3,000 a year ;Lord Gainford, as Vice -Chairman, tiou of the Committee has been acted on by the B.B.C., (Continued on page 223.) 119 MODERN WIRELESS February, 1929 K, U.S.A. (outlyingpossessions). H, Finland. 0 K, Czecho-Slovakia. Z, Denmark.P Y, Brazil.R Y, Lithuania. S M,Sweden. S P. Poland.S U, Egypt.T F, Iceland. U L, Luxemburg. U 0, Austria. V E, Canada.V 0, Newfoundland. W, U.S.A. Y I,Iraq. Y L,Latvia. Z L, New Zealand.Z S, Union of South Africa.