November. " IRELESS Vol
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FIODERN November. " IRELESS Vol. 2.No. 2. Edited by JOHN SCOTT-TAGGART, F.Inst.P., Member I.R.E. November, 1923. SPECIAL ARTICLES ON HOW TO MAKE : Vol. II. A HIGHLY SENSITIVE THREE -VALVE SET. By Percy W. Harris. A CRYSTAL RECEIVER WITH WAVE -TRAP. By G. P. Kendall, B.Sc. A PORTABLE ST 100 RECEIVER. By John Scott -Taggart, F.Inst.P. A HETERODYNE WAVEMETER. By Alan L. M. Douglas. A SINGLE VALVE -NOTE MAGNIFIER. ACCESSORIES FOR PEANUT VALVES. No. FRAME AERIALS. LOUD SPEAKERS. CRYSTAL HOLDERS. I FREE WITH THIS ISSUE-"JUNIOR WIRELESS." A 16 -PAGE MAGAZINE FOR BOYS. MODERN WIRELESS November, 1923 WECOVALVES . (PEA -NUT TYPE). N 44215-A. L'TENT Nos. 17580 (1915) 180090 46641-1921). Dimensions :2i in. X e in. Price - - Z1 10 0 THE WECOVALVE. THE new wireless valve which is to revolutionise wireless reception.Only 21 inches high and inchesindiameter,this small size valve. can be used equally well either as adetector oramplifierandoperatesoffasingledrycell,noaccumulatorsbeingnecessary. The WECOVALVE is the most economical valve existent, requiring only 0.25 of an ampere at o.8 to I.'volts,anditslifeismorethantwicethatoftungstenandother dull -emitter valves. The WE hasaspecial Bayonet Cap which prevents the possibility of destruction through careless insertion in the valve socket. Operating Characteristics :- Filament Current 0.25 amps. Detector Plate Voltage 17 - 22 volts. Filament Voltage o.8 - i.1 volts. Amplifier Plate Voltage 22 - 45 volts. THE SOCKET. ThisWECOVALVE socket is arranged for four soldered connections and has contact points faced with a gold and silver alloy which ensureperfectcontact with the base of the valve. THE ADAPTOR. The WECOVALVE adaptor makes it possible to usethe Wecovalve in your existingsets. Designed tofitinto valve sockets which carry the ordinary four pin type valves, this adaptor enableseveryonetotakeadvantageof the great economy in current consumption which the use of the Wecovalve effects. No. 44090. No. 44092. Dimensions : 1 in. x t in. WRITE FOR BOOKLETS- Dimensions:1i in. Pricels.6d. W.E. Co../32/W. 528 & W.E. Co./32/W. 529. Price 3s. 6d. Western Electric Compang Limited. (Wholesale Only) Connaught House, Aldwych, London, W.C.2.Telephone : Central 7345 (9 lines). Branches : Glasgow,Leeds,Birmingham,Manchester, Newcastle,Cardiff,Southampton,Dublin. 1111111111111111111111111111111111111111ffilll 11. November, 1923 MODERN WIRELESS The LISSENIUM AGE- LISSEN parts anticipate to-morrow- To aid users in obtaining the highest possible efficiency we have seen to it that there is a LISSEN part for every purpose.LISSEN made throughout, every part places at the user's command a service and efficiency which will sustain the fine tradition of the LISSEN Factory.Up to the present more than thirty times as many LISSEN parts have been bought in 1923 as in 1922. Why ? Because it has been found worth while to fit LISSEN parts.If you build your set you have got to use it-if you fit one LISSEN part you can depend upon it- if you fit all LISSEN parts you can depend upon the set. WE EXPECT TO HEAR FROM YOU IF YOU ARE NOT SATISFIED. AMERICAN TELEPHONY ON THREE VALVES ONLY -but ALL LISSEN PARTS Several reports have come to hand recently of American Tele- phony being received on 3 Valves only-but usirg ALL LISSEN PARTS, 1 LISSEN REGENERATIVE REACTANCE for 1stage H.F., 1 DETECTOR and 1H.F. A standard circuit was used. Build with ALL LISSEN PARTS ! 1.SUCCESSFULLY USEDinthe reception ofAMERICAN TELEPHONY- LISSEN REGENERATIVE REACTANCE replacesaerial reaction-non- radiating-introduced into the anode circuit, it forms an unequalled G / 6 first stage radio frequency ! Cheaper,easier to handle than plug-in coils 1-0 2.Rapid tuning is possible with the LISSEN REACTANCE-addsQ/6 range,power and steps up signals li eta good audio -frequency transformer 'LP S. USERS SAY LISSENSTAT CONTROL is the " most beautiful control imagin- able,"and it is !The interposition of the elastically deformable metal discs-there lies the secret of that perfectly free movement of the whole resister column of the LISSENSTAT. This feature CANNOT BE DUPLICATED, FOR 7/6 IT IS PROTECTED BY DEFINITE PATENT CLAIMS ... 4.LISSEN VARIABLE GRID LEAK-for correctgrid potential-/ 6 continuously variableto 6 megohms.Positive stops' both ways ... 5.LIS -EN VARIABLE ANODE RESISTANCE-continuously variable 20,000 to 250,eoo ohms-for dual, super -regenerative circuits, etc.Positive stops o/6 both ways.Same size and appearance as LISSEN Variable Grid Leak '4.4 S.LISSEN Ti TRANSFORMER, anincompirab eTransformer. Us^it alwa3s ni-diatelylot hind the Detectcr Valve and L.r pule ',Aver 3U/- 7.LISSEN TUNER-sharp tuning on all wavelengths-convenient 02/6 and compact -150 to 4,000 metres ... a. LISSENAGON COILS-there are three extra numbers in the series, Nos. 3o, 4o and 6o.This makes all the difference in tuning over the lower wavelengths, and °bviates the use of excessive capacity.These coils are intermediate between 25 and 35, 35 and 50, and 5o and 75 ...Price, 30 coil,4/10,40,4/10,60,5/4 9.LISSEN MICA VARIABLE CONDENSER-low resistance,7 7/6 no losses, signal strength always great, .00l, .00025, and .0005... 10.LISSEN VERNIER ADJUSTER-adds vernier adjustment to any existing condenser-drill one hole dose enough to bevelled edge of condenser dialrgt/. so that depression of adjuster engages its rubber friction washer on dial11 Other LISSEN PARTS includeLISIENT3 TRANSFORMER. Anexcellent LISSEN PARISINCLUDE EVERYTHING light 1r,.nsform r.One of the. 12,:st made 18/8 LISSEN T2 TRANSFORMER ... 25/- you need to go behind your panel LISSEN FIXED CONDENSERS, .000ito .00092 /-,.001 to .0032'8, .004to .0063/ - LSS TN PARTS have done away with r lithe bother of fitting -they go together easily-THEY ARE THE LARGEST SELLING PARTS There are other Lissen Parts as well. LISSEN PARTS ARE SOLD EVERYWHERE-should any attempt be made to sell a substitute, send direct to factory. No postage charged DEALERSLISSEN --claim your liberal stocking discount-all Radio, Motor,LIMITED Electrical and Hardware Factors sellI issen Parts-or send direct 20-24, WOODGER RD., GOLDHAWK RD., SHEPHERD'S BUSH, LONDON, W.12 N.B.-Close to Goldhawk Road (Met.) Station, Shepherd's Bush (Central London) or Hammersmith Tube.'Buses II and 32.'Phone: 1072 Hammersmith. - -- - - - - BUILD-WITH ALL LISSEN PARTS ! - - - - - - - - A MODERN WIRELESS November, 1923 11111111111 ill11111111111. 11111111111 H.T.C. mai! TRANSFORMERS reduce distortion to the absolute minimum. 3 -ELECTRODE VARIABLE CONDENSER . " CAPACITY BRIDGE A Striking Testimonial LENGTH Zee to the HEIGHT Vis' The principal factor to the success of the H.T.C. Transformer is he feature (prov. pat.) which gives agreater mass of iron at a lower magnetisation than any transformeryet produced of its size. VARIABLE BRIDGE CONDENSER High magnetisation of the iron core is the direct cause of distortion.The H.T.C. Transformer operates on telephony equal to other makes costing twice its price.That this is said is conclusive to the efficiency of the maker's designthattheH.T.C. Transformer should give the maximum amplification 3-E.V.C. with distortion reduced to the absolute minimum.Therefore noInteraction. H.T.C. Transformers may be mounted side by side. They have been proved exceptionally efficient on the S.T.i oo.This, with- out doubt, is one of the most rigorous tests to which a transformer may be (3 -Electrode Variable Condenser) subject. WHAT ANOTHER SAYS : London, In retailing your transformer at 15/-, Iconsideryou make a free present of a 10/- note with each one. Yours very truly, T. F. M. THE GENERAL ELECTRIC COMPANY Let your next Transformer be an H.T.C. You'll want another, becausethey (The largest electrical organisation in the United Kingdom, are free from distortion. Price 15 '- whose Technical Research Laboratories and staff are second to none) have,after careful test and examination, under- H. T. C. taken the manufacture of the 3-E.V.C. (under licence from VALVE HOLDERS High resistance Autoveyors, Limited). and low capacity are determined bythe spacing of the valve Variable Bridge Condensers are now obtainable from all legs themselves. In the manufacture GENERAL ELECTRIC CO.'S Branches, Agencies of the H.T.C. valve - holder, allowanceis and Gecophone Service Depots throughout the made for the varying spacing of legs of the world. differenttypesof Type C for below panel mounting. valves. Price 1/6. No metallic parts used in construction are exposed, making it impossible Beyond the wide use of the 3-E.V.C. as -a rejector of all to short the H.T. across the filament. Illustrations show two methods of mounting the H.T.C. valve holder. unwanted sounds, its enormous popularity as a CAPACITY There are at present in production five types of the H.T.C. valve -holder, BRIDGE has encouraged the manufacturers to improve it, providing a special pattern for all practical purposes. both as regards worktnanship and material used, to the very highest degree of efficiency.This involves a slight increase in retail prices, which, on and after Octobert St, will be Type A for above .00t Panel Mounting, 47/6.Cabinet mounted, 55/-. panelmounting. - Price The 3-E.V.C. isobtainable fromallhigh-class wireless 2/. dealers, or direct from Trade enquiries AUTOVEYORS are solicited. Radio Engineers and Contractors, H.T.C. ELECTRICAL CO. 84, VICTORIA ST., WESTMINSTER, S. W.1. 2 & 2a, BOUNDARIES ROAD, BALHAM, S.W.12 Telegrams: " Autoveyor," Sowest, London. TELEPHONE :Battersea 374. 11111111111111111111111111111111111111111111111111111111111111 iv November, 1923 MODERN WIRELESS EVERYTHING iEMEN for theRAD.O CONSTRUCTOR LOUD SPEAKER. An instrumentofthehighestclass. -even to Explanatory Wiring Diagrams.Showing all the components required, and. their relative positions for wiring up, these diagrains are in booklet form and are obtainable from your dealer CLEAR PRICE, each at 1 /- each.