A corner of the Awatea's radio cabin. -Photo co11rtesy A.W.A. v. Regarding the principle involved there is little fundamental d ifference betwe~n an Os cillator and a Signal Generator, yet p rices ra nge from approximately £40 to £ 150 and over-WHY? Because the instrument selling in the lotter price class is invariably a PRECISION 1.N STRUMENT and-as precision is NECESSARY in commercial radio design and production it is usual to PAY THE PRICE. Precisio'n is also very necessary for good service work. It was with the object of giving the service man the maximum of efficiency and precision at a PRICE WITHIN REASON that the " PALEC" G SERIES St:RVICE OSCILLATORS were progressively evolved. That a GOOD OSCILLATOR is a VITALLY IMPORTANT TOOL is now universally recognised. NOTE OUR SPECIFICATIONS-better still, VISIT US, and see a stock model demonstrat ed. We claim the following "HIGH PRICED" features :- Frequency Accuracy of HALF OF ONE PER CENT. on a direct reading dial; incorporation of a LOW IMPEDANCE 4-step PAD TYPE attenuator; reliability of REPEAT HEADINGS even over a period of years; unusually LOW LEAKAGE level; SINE WAVE Modulation at a mean value of 30 per cent.; incorporation of a compensated R.F. stage for maximum STAB ILITY, AMPLITUDE LEVE L and minimum ~~>~: · .:::·~~~ FREQUENCY MODULATION; six fundamental bands from 160 k.c. to 24 megacycles; full '-4...... range external Dummy Antenna. ·" ... - ·~
OSCILLATOR MODELS AND PRICES. 0 £11 15 0 :;~~: : g!o, AA~C. :~~~~~~d,' with · b~iit '-i~ ' o~tp'u't ' M.;t~~ ':: .. :::::::: .. :::: .. :: £15 15 0 Model GAV, A.C.-Vibrotor, dual operation from power supply ar 6-volt accumulator •...... £13 15 0 Model GA VO, A.C.- Vibratar, with built-in Output Meter £17 15 0 Madel GB, Battery operated ...... '. : : : : : : : : : : : : : : : : £11 15 0 Model GBO, Battery operated, with built-in Output Meter £15 15 0 PALEC MODEL V.C.T. COMPLETE VALVE AND C IRCUIT TESTER. Now in its third year and more popular than ever, the Palec Model VCT continues to supply the demand for a complete Valve and Circuit Tester in ane compact PALEC VACUUM TUBE VOLT-METER. unit. This new unit is en ideal instrument for either Dozens of letters (on hand ) from all service, design or laboratory work. The circuit States attest the reliability and efficiency follows closely a design popularised by a world of this versatile instrument. famous manufacturer of instruments and employs: The Model VCT, together with the new a 955 acorn tube as a diode rectifier in Polee Service Oscillator, can be aptly conjunction with a degenerative amplifier. described as the serviceman's right and Features include :-Ranges, 0-2.5; 10-50 Volts left hand, respectively. They enable every A.C.; 3.5 uuf. total input capacitance; 5 megohm rational test and adjustment to be made impedance at 50 cps.; scale accuracy of -1- - 3 % on a receiver, from the aerial coil right over the frequency range 50 cps. to 50 mega through to the speaker voice coil-in other cycles; low power factor through the use of words, with just these two instruments a mycalex insulation; Lineregulation; A.C. operation .. serviceman is well, if not fully equipped. PRICE, £13/15/-.
SPECIFICATIONS:-Tests all valves for MERIT and LEAKAGE; ELECTRO LYTIC CONDENSERS; PAPER AND MICA CONDENSERS; FOUR RANGES at current, 1- 10-50-250 m.a. D.C.; D.C. VOLTS, 10-50-250-lOOOV.; A.C. and OUTPUT VOLTS, 10-50-lOOOV.; a special LOW OHMS range from 0.1 ot e)PATON an ahm (ten ohms half scale) , with three other ranges ta 1 · megohm. Madel "VCT" far straight A.C. operation; price, £15/l 0/-. Country Model "VCT" (dual operation) works with equal efficiency on either the A.C. line or a 6-volt accumulator; price, £17 /17 /-. ELECTRICAL~;~ e ALL INSTRUMENTS PLUS SALES TAX. 90 VICTORIA ST., ASHFIELD. SYDNEY e PRICES SUBJECT TO ALTERATION WITHOUT NOTICE. Telephones: UA 1960-1982 LEADING DISTRIBUTORS ALL . STATES e SEND FOR OUR ILLUSTRATED CATALOGUE.
The Austrola1ian Radio World, February 1, 1940_ BUILD THE "RADIO WORLD"- ALL-WAVE SERVICE OSCILLATOR using the CALSTAN ALL-WAVE OSCILLATOR FOUNDATION KIT
AS SPECIFIED BY THE DESIGNER.
MAIN FEATURES IN CL UDE
• Continuous coverage from 150 k.c. to 30 m.c. in five bands. o Coils, band switch and attenuator are wired and sealed in a compact steel case, modulation choke and condenser gang being mounted The Calstan All-wave Oscillator externally. e ONLY FOUR COLOUR Foundation Kit Comprises- CODED LEADS to con . nect Foundation Unit 1 special Colston all-wave oscillator foundation kit, comprising into circuit. · ready-drilled steel crackle-finished cabinet, 7-1° x 6}66 x 10,·1 all-wave oscillator un•t (comprising five-band coil assembly and • Band coverage is acc1Jr ately pre-adjusted to attenuator mounted in steel box, with modulation choke and track with five-band condenser gang bolted in position I, tun;ng knob and celluloid dtrect-reading scale. indicator, scale for front of cabinet printed on heavy art paper. 4' Electron-coupled r.f. os PRICES: £7 /17 /6 Complete Kit; £4/17 /6 Foundation Kit. Coil c:llator circuit ensures Kit only, including gang condenser and cover, £3/7 / 6. high frequency stability.
NEW ECONOMY TYPE C.4.LSTAN OUTPUT METER (As illustrotcd on the right)
is now available for the indifation of the output of receivers when used in conjunction with the "RADIO WORLD" Service Oscillator. For further information, prices, etc., ring, write, or call- SLADE'S RADIO PTY. LTD. . EILSTan LANG STREET, CROYDON, N.S.W. 'Phones: UJ 5381, UJ 5382. Australia's Largest Manufacturers of Radio Servicing and Meosuring DISTRIBUTORS: N.S.W.: Radio Equipment Pty. Ltd., Martin de Launay Ltd., Bloch & Gerber Ltd., United Radio Distributors, John Martin Ltd., Murdoch's Ltd., Brice's Radio Service, Electric s.,rvicc Co., Newcastle. QUEENSLAND : Chandlers Pty. Ltd. SOUTH AUSTRALIA : Radio Whole salers Ltd., Adelaide. WEST AUSTRALIA: Norman J. Burnell & Ca. 13 Queen Street, Perth. VICTORiA : Australian General Electric Ltd., Mel bourne; Arthur J. Veall Pty. Ltd., Melbourne; Hartleys Ltd., Flinders Street, Melbourne. TASMANIA : Oatlands Garage. Oatlands. NEW ZEALAND: New Zealand Electrical Co. Stocks also avaliable trom Turnbull and Jones, all brc:n•hes. The Austrolasia11 Radio Wc;irld, February I, 1940, A SPECIAL KIT The Australasian RADIO WORLD Incorporating the ALL-WAVE ALL-WORLD DX NEWS Managing Editor: A. EARL READ, B.Sc. for the '' WORLD CRUISER Vol. 4. FEBRUARY, 1940. No. 9. COMMUNICATIONS EIGHT '' Don't take risks in building this magnificent receiver by using parts af doubtful quality. Those supplied in our kit of parts are guaranteed to be exact duplicates ot those selected CONTENTS: by the Technical Editor for the original model, and by using them you will en , ur~ getting the same outstanding performance. WRITE NOW FOR DETAILS OF OUR LOW-COST HIGH - QUALITY KIT OF PARTS. THE "1940 COMPANIONETTE THREE." 1940 version of a widely-popular kit, this little receiver gives 1 an amazing performance out of'. all proportion to its low cost. New A.G.-Battery "Duo" Portab e ------·----- ·--·- - 3 QUOTATIONS SENT POST-FREE BY RETURN MAIL. Book Reviews ····---·-···----·-·- -·-·--- --·-·------4 "RADIO WORLD" SERVICE OSCILLATOR. 1940 Companionette Three ····- --- ··--- -- ·---···---····---·-· 5 The all-wave service oscillator described in last month's issue Modulated Oscillators ····--··-·------····------·--·----·-· 9 will cut service costs per set and increase profits. Our low-cost kit of parts con be asse mbled ln two hours . . . success is Midget Three-Watt Amplifier ·····------· ·----·----·-- - 11 guaranteed, full assembly instructions supplied with each kit . WRITE NOW FOR OUR NETT World-Cruiser Communications Eight ··------·------13 TRADE PRICE. NO OBLIGATION. The Story of R.G.S. Radio (3) ···------·-- -· ------·· 27 FOR LIGHTNING SERVICE AND What's New In Radio ---·------29 LOW PRICES . • . • TRY US! Long- Horn Public Address Spe!lkers ----·-- ·- -·-···---- - 31 You deserve to be sore all over if you continue getting your Shortwave Review ·· ----·------·-··--·· -- ---·······---·------·- 33 radio and electrical supplies from firms which deal you out High Prices and Slow Service. Say to yourself, f;rmly : "My next order goes to Martin de Launay's!" lt'U be cne of the best business decisions you have ever made. We promise you that! We promise you a lightning service, careful packittg,. tip-top quality and keen prices. The "Australasian Radio World" is published Moreover, we promise to keep our promise, no matter whether YOUR order is big or small. trionthly by Read Publications. Editorial Offices: The next move is yours! 117 Reservoir Street, Sydney, N.S.W. Telephone FL 2842. Cable address: "Repress,'' Sydney. Advertisers please note that copy should reach office of publication by 14th of month preceding that specified for insertion. · Subscription rates: 1/ - per copy, 10/ 6 per year (12 issues), post free to Australia and New Zealand. Pope 2 The Alntrolosion Radio World, February I, 1940. ... This cabinet, measur ing only 1 3}" x 9-:}" . x 5Y' and covered in smart airway canvas, houses four Breville port ables-the Models 156 and I 57 four and five valve receivers for bat tery operation only, and the Models 168 and 169 five and six-valve "Duo" receivers for a.c. and battery operation. A test report on the Model 169 appears below. N e"1 A.C. - Battery ~~ouo'' Portable Latest Breville release has built in a~e. power sup ply ~ Gives remarkable performance during tests. THE introduction of the 1.4-volt Mis senden Road, Gamperdown, and earth connections. However, the valves some eighteen months ago N.S.W., who recently added to thdr efficiency of the built-in tuned loop removed every practical objection already extensive range of portables aerial is so high that it provides more to portable radios that had previously the "Duo Five" (Model 168) and "Duo than ample pick-up under almost any prevented them from becoming widely Six" (Model 169). These are five and conditions. popular. The very high overall effic six-valve models, respectively (includ Inside the cabinet is a horizontal iency and modest "A" and "B" cur ing rectifier) designed to give dual shelf on which the chassis rests, an rent requirements of these valves purpose operation from either self Eveready Type PR8 "A" unit being made possible the design of light, contained batteries, or the a.c. mains located alongside it. The compart compact and entirely self-contained (220, 240 or 26.0 volts). ment underneath the shelf houses the receivers that could be carried any Last month one of the "Duo Sixes" two Eveready type PR45-'volt "B" where, and that would give full loud was supplied to "Radio World" for batteries and the power cord. speaker reception day or night, in al test, and it has proved itself a re The steel chassis, which measures most any location. markable little receiver. only 10 'Ii" x 5" x 1 %, ," accommodates To-day almost every receiver manu the five valves, dial, i.f. transformers, facturer in Australia is marketing Constructional Details. 5" Rola speaker, the three-gang con one or more 1.4-volt portables, which It is housed in a cabinet similar to denser and power transformer. are available in about every conceiv that illustrated above, measuring ap Provision For Headphones. able design and valve 11rrangement. proximately 131h" long x 9%,'' high There are three controls in front of While most models are designed for x 5%" deep, and finished in attractive the cabinet, these being (left to right) battery operation only, there are some grey-toned airway canvas with multi tuning, battery/a.c. switch, and com for which external a.c. power units coloured stripe. Weight of the re bination on/ off switch and volume are available, and several with built ceiver is 20 pounds, complete with control. A refinement that many in a.c. power supplies. batteries. users will appreciate is the provision Both the dial and the three controls that is made for headphone operation, Two Breviil'e "Duo" Models. are recessed into the front of the. cabi the necessary sockets being located Prominent among manufacturers (jf net. The back of the latter is held in a small recess in the left-hand end the last-named type of receiver is into place with two screws, which also of the cabinet. This feature will be Breville Radio Pty. Ltd., of 67-73 act as terminals for external aerial (Continued on page 40). The Australasian Rodia World, February I, 1940. Pa9e 3 ~~~~~"""""""'~ ! -Book Reviews TECHNICAL I The Radio Amateur's Handbook: 1940 Edition. BOOKS Despite the handicap of war, the amateur transmitter with a keen in Important * Price Pos.toge terest in the experimental side of 1940 Rodio Amoteur Hand- radio is not likely to throw everything book ...... 10/- 9d. to the winds. Although experimental Radiotron Designers' Hand- book ...... 3/- 4d. activities in the way of actual trans • Radio Laboratory Handbook, mission from his amateur station are necessarily suspended, he will in his Scroggie. (This book The "Australasian Radio World" should definitely be in mind's eye, cherish the day in the un the possession of every known future when he· will be able to is about to launch a vigorous experimenter, engineer get back on the air and continue policy of improvement and and set-builder. It is inter-communication with fellow radio expansion. published by the Wire- amateurs far and wide. less World) . "' ...... 13/6 6d. Radio Physics Course, Perhaps from the chaos of this war Ghirardi ...... 30/- 1I3 stricken world, the time may come Mc.dern Radio Servicing, when sane governments will make . Ghirardi ...... 30/- 1I3 available every possible facility for Prir1ciples and Practice of wider instead of narrower frequency Radio Servicing, Hicks . . 24 I - 9d. channels for amateur communication, The first announcement in this Ra:-:Ho Manuol, Sterling . . 42/ - 1I3 with the object of promoting better direction is that, as from the next Vibrator Manual and Pro- understanding between men in the issue, the editoriol chair will be fessional Serviceman's world to come. Despite war, the Auto Radio Guide . . . . 2/6 3&. occupied by- Servicing by Signal Trac- science of radio doesn't stand still, and ing, Rider ...... 16/ - 9J. while at this stage much of its appli Amplification and Distribu cation is along the lines of offence and tion .,f Sound, by Green- defence, the interests of the experi lees ...... 17/6 Sd. menter are still unhampered in yet A. G. Hull Handbllok of Technical In- neutral America. struction for Wireless From that country comes the Telegrophists, Dowsett .. 34/- 1 / seventeenth edition of "The Radio Wireless Direction Finding, Amateur's Handbook," published by Keen ...... 42/- 1 /3 the A.R.R.L. at the offices of "QST," * Radio Craft Library- · Hartford, Connecticut. This 1940 Home Recording ...... 4/6 3d. Practical Public Address 4/6 3d. edition is, if that is possible, bigger and better than preceding issues, con Breaking Into Radio Ser- Mr. Hull, who has been associ vicing ...... 4/6 3d. taining 575 pages of profusely illus The Cathode-Ray Osdllo- trated and diagrammed radio develop ated with "Wireless Weekly" for scope ...... 4/6 3d. mental material covering the subject the past ten years, originally as Servicing with Silt Anoly- from A to Z. technical editor and latterly as sers .. 4/6 3d. It is natural that with most Aus editor of both "Wireless Weekly" Short-wave Beginners' Book 2/- 3d. tralian amateurs turning their cap Short-wave Hook-ups . . .. 4/6 3d. abilities to the serious business of war and "Radio and Hobbies," is Quiz: Short-wave Radio communications in one or other of the recognised r.s Aus.tralia's fo remost ...... 2/3 3d. Book . . . . . services, ·touch with the latest de Cathode Modulation, by technical journalist. His wide ex Jones ...... 9/6 4d. velopments in the past few months is perience should ensure that "The likely to be casual. This latest The A.R.R.L. Antenna Book 4/6 4d. Australasian Radio World" will R.C.A. Receiving Tube A.R.R.L. Handbook is just the volume Manual ...... 2/- 4d. to breach the gap and to keep one maintain its position as the raaio Technical Manual . . '3/9 6d. fully up-to-date. It would be impos technical authority . Cathode-Roy Tubes and sible here to detail all the sections of Allied Types 2/- 3d. this new edition, and it is sufficient to say that every possible phase of radio reception and transmission is fully covered, from fundamentals to * the intricacies of ultra-high-frequency McGILL'S AGENCY and micro-wave practice of these times. 183-5 Elizabeth Street There are many new ideas in trans WATCH NEXT MONTH'S ISSUE; mitter construction, and the receiver . ORDER YOUR COPY NOW! Melbourne side alone is of particular interest, (Send for our free Catalogue of Tech this being in Australia, one aspect of nical Books and Maga:z:ines on all amateur radio on which much work subjects). can be done in preparation for the future. (Continued on page 40). Page. 4· The Australasian Radio World, February 1, 1940. ' The "I 940 Companion ette" is housed in a wooden cobinet covered in airway canvas and measuring ap proximately 15" x 7" x 8." While designed, primarily to bring in locals at full speak er volume, excellent inter state reception is. easily pos sible with this little receiver. 1940 Companionette Three Full four-valve performance from three valves is given by this a.c. t.r.f. receiver, which employs a 6F7 as combined pentode r. f. amplifier and triode detector driving a high-gain 6AG6G output pentode. Automatic regeneration is an attractive feature. HE "1940 Companionette" is a readers throughout Australia, some numbers of 'Radio World,' i' decided Tnew version of one of the most excellent performance reports being wish to repo.rt on the reception this successful little receivers ever fea received. Actually the original model little t.r.f. set has produced, with tured in "Radio World." is still being built, as this extract to build the 'Companionette Three'. ad Originally described in the March, from a letter recently received from vertised in the March, 1937, issue. I 1937, issue, a revised version appear Mr. M. H. Hughes, a reader in Parkes, only approximately 14 feet of inside ed in the May, 1939, issue. Hundreds N.S.W., shows:- aerial and no earth. of these sets have been built up by "After going through some back "Tested at 7.30 p.m., the following stations were brought in besides the local, 2PK:-N.S.W.: 2GZ, 2WG, 2CO, 2CH, 2BL and 2FC. Victoria: 3LO and 3AR. South Australia: 5CK and 5CL. All were picked up at good volume. I have a five-valve sup(jrhet on hand, and it has been out-classed by the '.Companionette Three' for selectivity." Other readers using outside aerial and earth systems in fair locations have reported logging up to thirty stations in Australia and New Zea land, all at good speaker strength ] and excellent tone. The circuit of the "1940 Com panionette," together with under UNDER -SOCKET CONNECTIONS socket connections of the 6F7 ancf 6AG6G. Tho A\lstroloJion Rodio W9rld, Fobruary 1, 19i0, Page 5 Two views of the completed chassis. Nate the method of mounting the speaker so that it projects beyond the front wall. The rear view on the right shows the raamy layout adopted, the chassis having been designed in accordance with the latest trend in mantel receivers. Is Actually A "Four." once the tension has been adjusted grid winding of the detector coil. The secret of this exceptional per correctly. The triode section of the 6F7 is formance lies in the use of the 6F7 The chassis for the "1940 Compan connected as a leaky grid detector, triode pentode, which really comprises ionette," which measures 15 11 x 6Yz 11 which in turn is resistance capacity two separate valves in the one glass x 3, 11 is of 18-gauge steel, finished in coupled to the 6AG6.G -0utput pentode. envelope, -0nly the cathode being com battleship grey duco. The original mon to both. was supplied by Acorn Pressed Metal Back-Bias For Output Pentode. The fact that the 6F7 is a double Pty. Ltd., of 1 Marshall St., Surry The bias required for the latter valve does not detract in the least Hills. valve with a plate and screen voltage from the efficiency of its component The cabinet, which was supplied by of 250 volts - is -6 volts. As shown sections. In other words, the overall Western Manufacturing Co. to the by the circuit, back bias has been em 11 ployed by connecting a 120-ohm resis gain it gives is ~xactly the same as Editor's specifications, measures 15 Yz if separate valves were used. Thus long x 7~{ /1 deep x 811 high. tor between earth and the centre tap in the "1940 Companionette," there of the high voltage secondary on the How The Circuit W !)rks. are really four valves-a pentode r.f. power transformer, the 6AG6G grid amplifier, triode detector, output pen The circuit shown on page 5 will be resistor being returned to the centre tode and rectifier. found very simple to follow. The tap. signal picked up by the aerial is ap The total "B" current taken by the Steep Slope Output Pentode. plied in the usual way via the first set flows from earth (i.e., chassis), The output pentode chosen is the tuned circuit to the grid of the 6F7 back through this resistor to the high now well-known Brimar 6AG6G, a pentode section. After amplification voltage centre tap. It is the voltage valve that is ideal for a small receiver it appears in the plate circuit and is drop across this resistor, in this ·case of this type, as it has exceptionally transferred from the primary to the amounting to 6 volts, which comprises high sensitivity. A signal input of on~ 2 volts r.m.s. will fully load it to deliver -0ver four watts of output. "1940 Companionette Three.'' 1 10,000 ohm 1-watt carbon ( l.R.C.l. The rectifier used is a 5Y3G, the 1 1,000 ohm I -watt carbon ( l.R.C. l. List Of Ports. 1 300 ohm I-watt carbon ( l.R.C.). mod.ern octal equivalent of the 80. 1 150 ohm wirewound ( l.R.C. l. sp"cial cabinet covered in airway can 1 100 ohm wirewound (l.R.C.). In the "1940 Companionette" the vas (Western). circuit as used for last year's model steel chassis, . stamped and drilled to FIXED MICA CONDENSERS: specifications (Acarn). 1 .0001 mfd. IT.C.C.l. has been retained without alteration, power transformer, 385 c.t., 385, 60 1 .001 mfd. (T.C.C.). but the layout has been completely m.a., 6.3v., 2 amp., 5 v., 2 amp. FIXED PAPER CONDENSERS: ( Radiokes). 1 .02 mfd. ( Ducon). rearranged and a larger and more 1 small 7-pin wafer socket. 1 .01 mfd. (Duconl. attractive dial used. As well, the 1 octal wafer socket. 2 • I mfd. ( Duconl. 1 4-pin wafer socket. cabinet is c-0vered in the latest air 2 air-cored coils, 1 aerial, 1 r.f. (R.C.S., SPEAKER: way canvas that in conjunction with Radiokes). 1 dynamic speaker, to match single for 2-gang condenser (Stromberg-Carlson). 6AG6-G, 2,500 ohm field (Rola F5B, the Reedtex material used the 5,000 ohm volume control (R.C.S., Amplion). speaker grille, ensures a very attrac Radiokes). VALVES: tive appearance. 2 terminals, 1 red, 1 black. I 6F7, 1 6AG6G, 1 5Y3G. 2 control knobs. I rubber grommet. MISCELLANEOUS: New Dial, Ohassis And Cabinet. 1 midget dial cind escutcheon ( Efco) . 2 doz:. 3/8" nuts and bolts; 4 yards 1 power so_cket and plug. push-back (solid and flexible); 1 6ft. The dial is the new Efco midget 2 8 mfd; wet electrolytics ( T.C.C.). length power flex and plug; I The Australasian . Radio World,, February 1, 1940. DESIGNER 1S HANDBOOK Invaluable Reference Fresh from the printing presses, the latest edition of the Radiotron De- 3igner's Handbook (1940) places this already widely-known publication in the category of established text-books on radio design. In a handy octavo size, it comprises no less than ·352 pages-its eight sections being dealt with in 40 chapters. Profusely illus trated throughout, over 300 diagrams of circuits, graphs and instruments, exhaustively deal with this continu ally progressing science. With special attention to radio conditions and re This under-chassis view shows the extreme simplicity of the wiring, only a handful quirements in Australasia, its con of pigtail components being required for the jab. tents are as modern as to-day and it is an indispensible adjunct to every the negative bias applied to the out ated. However, this possesses the ser radio engineer's and technician's put pentode. ious disadvantage that in a receiver library. intended for ordinary domestic use, A detailed cross reference in alpha How Volume Is Controlled. persons not accustomed to handling betical order does away with labor. A simple and well-tried method of critical controls find regeneration very ious searching and the comprehensive controlling volume, that is also very difficult to adjust properly. At the nature of this volume is indicated in effective, has been incorporated. It same time, in a set of this type a the following summary of its consists of a 5,000 ohm potentiometer certain amount of regeneration is a contents:- connected in series with the 6F7 300- very desirable feature, as it makes PART 1.-A.F. Amplifiers, Power Am an immense improvement to both sen plifiers, Relation between Output and bias resistor between the aerial end Speaker, Biasing, Bypassing, Decoupling, of the r.f. primary and the 6F7 cath sitivity and selectivity. Fidelity, Distortion, Negative Feedback,. ode, the moving arm being taken to Miller Effect, Audio Amplifier Design, In last year's model this problem Tone Compensaton and Control, Vol4me earth. : i I was overcome by employing a special Expansion and Compression, Recording, type of automatic feedback, designed Pick- ups, Microphones, Microphone Am This provides a double control in that plifiers, AF. Mixing Systems, Decibels, both the 6F7 bias and the signal in to give the greatest boosting effect to Nepers, Volume Units and Phons. put voltage are both controlled simul signals at the low frequency end of PART 11.- R.F. Amplifiers, Frequency taneously. With the moving arm of the band, where the sensitivity of the Conversion, Tuned Circuits, Calculation of Inductance, Low-Loss Inductances, l.F. the potentiometer at the earth end, average t.r.f. receiver falls off badly. Amplifiers, Detection, A.V.C., Automatic the 6F7 bias is at minimum and the Once the correct amount of feedback Frequency Control, Frequency Drift, Reflex r.f. signal input is at maximum, which has been adjusted, its operation is en Amplifiers. is the condition for greatest volume. tirely automatic, the nett effect being PART 111.-Rectification, Filtering and to give even, high sensitivity over the Hum. Wth the moving arm at the other end PART IV.-Voltage Dividers, Dropping of the resistance, the 6F7 bias is at entire band. As well, selectivity is Resistors, Transformers, Iron-Core lnduc;t maximum, g1vmg mmmmm gain, greatly improved. anc"s, Voltage and Current Regulators, Tuning Indicators. while the r.f. signal input is shorted In practice, the set should be com PART V.-Receiver Tests and Measure to earth. Intermediate positions of pleteiy ·assembled and tested to en r ·.ents, Valve Testing, Valve Voltmeters, the volume control provide corres sure that everything is working per Meosurino Instruments. ponding control of volume. fectly. Feed-back can then be intro PART Vl.- Va!ve Constants, Graphical Representation of Valve Characteristics. A fixed tone control, consisting of duced as follows : The bottom end PART VI I i. ~ Resistance, Capacitance, In- a .01 mfd. fixed condenser connected of the detector grid winding is de ductance, Vectors, Complex Algebra, from the plate of the 6AGGG to earth, tached from earth, and to this lug is Simple Trigonometry, Units. provides very well-balanced tone, ob then soldered a length of cotton PAkT Vlll.- Tables, Charts and sundry viating the need for a variable con covered or enamel wire-26 d.s.c. or Data. trol. However, by trying slightly enamel will do, though the gauge is The Radiotron Designer's Handbook smaller and larger values of conden not particularly important. is obtainable from Booksellers and sers than that shown, builders can This lead is then taken over to the Stationers at 3/- per copy in Austra1ia vary the tone to suit their own tastes. base of the aerial coil former, and (posted 4d. extra) . Copies may also at the point where the wire passes be purchased direct from:- Automatic Regeneration Included. over the hole in the centre of the The automatic regeneration feature latter, some half-a-dozen turns are AMALGAMATED WIRELESS introduced with such success in last wound around a pencil. These are VALVE CO. PTY. LTD. year's model has been retained in the inserted up inside the aerial coil latest version In the first "Compan former, and then the remammg free 47 York Street, Sydney. ionette" to be described, manually end of the wire is connected to controlled regeneration was incorpor- chassis. G.P.O. Box 2516 BB. The Australosion Rodia World, February 1, 1940. Page 7 · This sketch shows the complete under chassis wiring, and if studied in conjunction with the under-chas sis photograph will enable inexperienced set-builders to com plete the assembly successfully. - NOTE - CONDENSERS ~HOWN THUS : ~ RE~ISTORS :.HOWN T~us : ~ It will then be found that regener wiring, a pair of leads is run from circuit and under-chassis wiring dia ation is available. If there is "squeal the .5-volt winding on the power grams, the valves can be plugged in, ing" on stations, then there is too transformer to the filament lngs on aerial and earth connected and the much, and the number of turns on the rectifier socket. A further pair is power switched on. While doing this, the winding will need to be reduced. taken from the two 385-volt lugs to carefully watch the rectifier for any In the set described, three turns in the plates of the rectifier. signs of sparking or of a blue glow, serted well up inside the former were. The remainder of the components, either of which denotes a serious ample to produce the desired result. with the exception of the dial and overload due to a short circuit some Incidentally, if no regenerative effect speaker, can next be mounted. These where. If either occurs, switch off at all results, the direction of the comprise the condenser gang, aerial immediately and re-check the wiring. feed-back winding should be reversed. and r.f. coils, electrolytics, and vol With the set operating correctly, it Air-cored coils are specified in the ume control. Before the condenser can be aligned before it is mounted list of parts, but undoubtedly readers gang is mounted, a 6" lead should in the cabinet. To do this, set both with iron-cored types on hand will be soldered to the fixed plate lug trimmers on top of the gang a couple want to use them. However, if iron underneath each section of the gang. of turns or so out, and tune in a sta cored coils are used, the reaction These leads pass through the chassis tion somewhere near the centre of winding cannot be inserted inside the and are connected to the appropriate the band. Next, carefully adjust the former, as this is not hollow as with lugs on the coils. aerial trimmer for loudest response. the air-cored type. A simple way A point that should be noted here "\Vith the set -operating satisfactor out of this difficulty is to drill two is that the 8 mfd. electrolytic filter ily, automatic reaction can be added, small holes in the base of the former, condenser on the input side of the as described last month. The amount through which the reaction winding smoothing filter must be insulated of feedback reequired is adjusted· by can be taken . Thus instead of this from the chassis; other~ise the bias varying the coupling' between the winding being inside the former, two resistor will be shorted out. feedback winding and the grid wind or three turns are put on outside, be Next, commencing with the aerial ing of the aerial coil. This adjust low the grid winding. terminal, wire the aerial coil, pentode ment should be made while the set is tuned in to the highest wavelength The Construction Outlined. section of the 6F7, detector coil, triode section -of the 6F7, and so on until the station it is desired to receive. Ad The parts to mount first of all com wiring is completed. Before the set is just the coupling on this station until prise the three valve sockets, power switched on, however, the entire as a "swish" is heard as the station is socket and aerial and earth ter sembly and wiring should be care tunEcd in. Because the amount of minals. The power transformer can fully checked to ensure there are no feedback gradually decreases as the be bolted in place and the heater mistakes. capacity of the condenser gang is de wiring put in. To do this run a pair creased, this means that the set will of leads from the 6.3-volt winding on Lastly, the dial and speaker can be not break into oscillation at any part the power transformer to the heater bolted in position and the control of the band. lugs of the 6F7. A further pair of knobs fitted. The set is now ready to be switched on. While the fitting -of automatic re leads is run from these lugs to the action as described is optional, it is corresponding Jugs on the socket of Aligning And Operating The well worthwhile including, as it makes the 6AG6G. The centre tap of the "Companionette." a striking improvement to both gain 6.3-volt_ winding is then earthed. After the wiring has been thor and selectivity. To complete the rectifier socket oughly checked by reference to the (Continued on page 39) Page 8 The Aust_ralasian Radio World,. February J ,_ 1.940. This A. W. A. signal generator (type 2R3911), which will supply modulated or un modulated signals ot any frequency between 90 kilo- cycles and 27 megacycles per second, is design ed to give a very high order of ac turocy. Aligning Reeeivers In this instalment from the Radiotron Lecture Service series, continued from last month's issue, the correct procedure for aligning superhets and tuned radio frequency receivers is outlined in detail. The design and app- lication of multi-vibrators are also discussed. N the broadcast and short-wave the output of the oscillator through By rer,eating this process it should be 0 bands sufficient reference polnts the i.f. channel of a receiver know:1 possihle to draw an accurate calibra may usually be found by hetero to be aligned at or near this fre tion curve for the whole band. dyning the oscillator against stations quency. Once having determined th2 Calibration of the 175 k.c.'s i.f. of known frequency, and listening for approximate setting, accurate cali zero beat in a receiver. Some care has band is also possible by similar bration may be carried out with the means, but greater care must be to be exercised particularly on the aid of the second harmonics. short-wave band to avoid confusion exercised in discriminating between due to harmoaics from the service os If, for example, the receiver is the various harmonics. cillator and "second spot" tuning tuned to a station on 9·30 k.c.'s, and effects in the receiver. the oscillator output lead brought Aligning Receivers. close to the aerial· terminal, a beat The alignment of superheterodyne On the 465k.c.'s i.f. band a more note will be heard as the oscillator receivers is a fairly standardised indirect method must be adopted. is tuned through 46.5 k.c.'s. Similarly procedure and does not involve any The approximate dial setting for 465 with the fundamental on 460 k.c.'s the great difficulties provided certain pre k.c.'s may readily be found by feeding second harmonic will fall on 920 k .c.'s. cautions are taken. Final alignment should only be carried out after all ~ voltages have been adjusted, and 100.,..,...,.,..,.,...,.,..,..-• l -MI.,._ .,.,.,..,..nj__ TTI.,._.,.,.,. .,. _,., : 'TTI-n-=mrn==n_T~~ 1 111 should preferably be the last oper 80 A typical oscillator ation on a chassis. It is not good calibration curve, in practice to carefully align a receiver which dial readings and then to disturb the wiring or sub are plotted against ject the chassis and components to frequencies in k.c.'s. undue stresses. -' As a general rule, the input voltage < 20 c from the modulated oscillator should be kept small and alignment carried 0 J600 1200 1000 eioo eoo out with the gain control (or con f"R(QUENCV KC/5, trols) of the receiver in the maxi- The A11~trala~ian Rodia World, Febr11~uy 1, 1940, mum position. The use of small in Unnecessary alteration of the i.f. in +4!.V. put voltages is particularly important such receivers may lead to trouble when dealing with a receiver equip with "joeys" and will upset dial ped with a.v.c., since at higher tracking. The frequency of the signal inputs the a.v.c. becomes fully modulated oscillator should be adjust operative and changes in output level ed for greatest output from the re are greatly reduced by its action. ceiver and then, without alteration Furthermore, the r.f. and .if. amplify of the frequency the settings of the · .Thi! A11strala~ia!I Radia World, F~bruary 1, 1940, ; ·A general view of the completed amplifier, which is. built on a steel chassis measuring only 7.J/' x 5}" ~ 2-}.ll ~Midget · 3-Watt ; Amplifier Built from ''junk-box" parts at next to no cost, this midget amplifier nevertheless delivers ample power for a small dance hall, with excellent quality of reproduction. By L. WILSON HIS amplifier was designed origin couple of old 'phone jacks, four phone used is the one described in T ally to provide dance music in a sockets, a few old resistors and con the June, 1939, issne of "Radio small local hall, and has been densers, etc., three knobs and four old Worl'd." The tone control is optional, used in that capacity regularly for valves--comprising a very old 80, a but its advantages make it well worth the past six months. 2A5, 58 and 57. while. The finished job had to be compact With these in front of me, I ex About The Layout. and cheap, so, with economy as a by perimented with a few circuits, even E~ word, I cornmenceci going through the tually selecting the one shown here. An idea of the layout can be ob- junk-box. I unearthed an old power Two input channels are provided for tained from the photograph, while transformer, two electrolytics, a microphone and pick-up. The micro- elsewhere appears a list of the parts needed. The 18-gauge steel chassis Midget Amplifier. 2,500 ohm 1-watt carbon ( l.R.C. I. measures 7~" x 5%" x 2%." If desir 1,000 ohm 1-wott carbon ( l.R.C.). ed, the completed job could be housed 450 ohm 1-watt carbon 11.R.C.). List Of Parts. in a ventilated steel case measuring FIXED CONDENSERS: only 711;l," x 5%" x 71/z." 1 .01 mfd. tubular ( Ducon I. aluminium or steel chassis 7-4-" x 5}" 1 .02 mfd. tubular ( Ducon I. x 2}" (Acorn). 1 .OS mfd. tubular (Du con l. The shielded valve nearest the power transformer, 385v. C.T. 385v. 4 . 1 mfd. tubular ( Ducon I. power transformer is the 57. On the 60 111.a., 2.5v., 2a., 2.5v. 3a.; 5 v. l .5 mfd. tubular ( Duconl. 2a. 1 25 mfd. tubular ( Duconl. left-hand side of the chassis in the 3 6-pin and 2 4-pin wafer sockets. 2 8 mfd. wet electrolytics ( T.C.C., front is the 58, with the 80 behind it, 2 500.000 ohm potentiometers ( l.R.C. I. Duconl. 1 . 1 0,000 ohm potentiometer ( R.C.S., almost hiding- the 2A5. Radiokesl. ' VALVES: 2 'phone jacks. 1 51, 1 58, 1 2A5, 1 80. This layout should be adhered to as 2 valve shields. 3 knobs. SPEAKER: close as possible so that compactnes;; 3 indicator plates. 1 8," 1 O" or 12" speaker to match single can be combined with short leads, etc. 2 valve caps. output pentode, 2,500 ohm field (Rola, (In the photograph the shield has 2 Dalton spring terminals. Amplionl. been removed from the 58 to obtain FIXED RESISTORS: M ISCELLAl-!,EOUS: a better view of the valves behind). 1 1.5 megohm 1-watt carbon ( l.R.C.). 2 doz. 3/8" x ·1-" nuts and bolts, hook 2 .5 megohm 1-watt carbon ( l.R.C.). up wire, shielded braid, 1 yard tinned 2 .25 megohm 1-watt carbon 11.R.C.). copper wire, 2 yards power flex and The fader system shown in the cir 1 .1 megohm 1-wott carbon ( l.R.C. I. plug. euit is suitable only when the mike and pick-up are to be used separat'lly. The Australasian Rodia World, February l, J 94-0. Pa5111 11 3 Great Engineering Features P CONTROLSt I ermanen y Circuit of the midget amplifier, which uses a 57 first audio stage followed by a Q1JIET triode-connected 58 driving a 2A5. All pioneered and perfected by IRC • . . All three avail" able only in IRC Type CS come noisy in operation can be given Volume Controls ..• and at ordinary control prices. a new lease of life, as efficient rotary filament or dial light switches for battery sets can be made from them, A NO SLIDE ••• ~ with very little alteration. y NO FRICTION MIKE ':' Metal-to-metal, sliding contact be With the type shown in the dia tween rotor arm and end terminal gram, take out the pile ·of little discs is "out." Noise hasn't a chance. ALTE P.lllATIVE 'FADER" CIRCUIT The IRC Silent Spiral (positive which make up the resistance (this contact) Connector sees to that. can be done with the point of a pen knife). Then place a fibre washer, J~THE GLIDING about the same diameter as the discs, ~ ELEMENT RIDER on one end of the disc channel for insulation and replace as many of the Instead of a single "rough·riding" contact to element. five separate discs as possible, so as to hold the spring.like contacts give a cush pile tightly in position. The moving . ioned "knee-action" effect. Con· !actor acts independently; each arm of the volume control may re tracks smoothly in perfect unison; quire bending a little, so that it each is plated. rounded. smoothed reaches further over the surface of to avoid abrasion and wear. Alternative fader and mixer circuits the fixed contact point. The switch are shown in an accompanying will make good contact as it is self ~SMOOT .. cleaning. ~i:3J' AS GLASS ••• diagram. The ideal surface for noise.free The hall where the amplifier is used In order to ensure rigid economy contact is supplied by the famous accommodates between 60 and 70 when used as a dial light switch, a IRC Metallized type resistqnce ele people, and I have found the outpat, ment permanently bonded lo a piece of rubber may be held in pos- . moisture·proof bakelite base. You which is approximately three watts, ition by means of a split rivet through can actually feel the difference as to be ample for these crowds. The the case, between the base of the mov- · the ·s cFfoger Knee Action Contac- speaker should be well baffled (for a - ·t~r .- i.S;- _ r-9tate.d across this element. ing arm and the side of the case to -Standard .Types ·-----············-· 4/6 12" speaker the baffle should b2 at act as a spring, so that the control Switch Types ------·--·· 5/6 least 4 feet square). knob must be held in the "on" pos Sole Agents for Australia: ition while in use. No doubt other Battery Switches From Old types -0f old volume controls could Wm.J. McLELLAN&Co . .. Volume Controls. also be adapted for use as switches. - 55 YORK STREET Old volume controls that are of no H. W. Ungers (ex-VK2UJ), Alec more use as such through having be- town). The Australas.ian Radio World, February 1, 1940. The completed "World- Cruiser" is a de luxe receiver that is ideal for DX work on oll bonds. It is partic~1larly easy to handle, ihe five-band directly-calibrote::I dial making station location a simple matter. World-Cruiser CoD1D1unieations 8 Uses sensational new R. C. S. five-band 9. 8 to 550-metre coil unit * Latest permeability tuned i.f. 's *Special directly-calibrated dial .lf Built-in b.f.o. unit 'f Tremendous sen sitivity, knife-edge selectivity, and perfect tracking with ample overlap on all bands. URING the past few years several dozen com frequency stability. All are provided by the D munication type superhets have been des "World-Cruiser." There is an ample reserve of cribed in various Australian radio magazines, gain, while selectivity is such that the set will but the "vVorld-Cruiser Communications Eight" cut through severe QHM to bring in the trans is the first to be featmed using a switch-type coil mission required. assembly in place of plug-in coils. Its construc tion has been made possible by the release by Actually the "World-Cruiser" is a delight to R.C.S. Radio of a five-band coil unit that is the handle, its performance leaving nothing to be result of some months of intensive developmental desired even by the most critical of DX fans. The work in the R.C.S. design laboratory. sense of strain felt after an hour or two of DX chasing on smaller receivers, with the "World , The design of a coil unit of this type offers Cruiser" gives place to a feeling of "it is there if many problems, among the most important fac you want it," the only requirement being to find tors being tracking, band coverage, gain, selectiv the correct dial setting and allow the receiver to ity, and the maintenance of optimum oscillator do the rest. grid current over all bands. In the R.C.S. type DW30 kit, all these are above criticism, and, as a result, the performance of the completed receiver 'l'hree-Stag-e Five-Band Assembly. is outstanding, and compares more than favour ably with expensive American designs. The coil unit around which the "World-Cruiser Communications Eight" was designed is a three Many Attractive Features. stage five-band assembly comprising aerial, r.f. and oscillator sections, with 10, 20, 40, 80 and The main requirements of a receiver of this broadcast coils in each. It is built up around a type are a high degree of selectivity, high usable three-section five-band wavechange switch with sensitivity (i.e., minimum noise level) and good silver-plated contacts, designed specially for the Th~ A11stralasian Radio World1 February 11 1940, .•-1 ..: :i 0 -" tH :I 2 ..:.... "'0 > 0 > ""Q , ..> 'Tl.. Vl ti ,;:, I ] ll 0 "' "':'.!"" TONE QUALITY mars radio enjoyment The brilliance and tone fidelity of to-day's radio programmes may be completely marred by worn-out valves. Studio realism, broadcast by mod ern stations, can be reproduced in your home only when the valves in your radio function efficiently. To secure the full pleasure of listen ing, Re-valve with Specify . • . RADIOTRONS for the "World-Cruiser Communications Eight" described in this issue. --~Y"J'--~··· The A11stralasian Rodia World, February I, 1940. job. An important feature is that WHEREVER YOU GO provision is made on each section for shorting: out all unused grid windingc· Partitions of cadmium-plated steel provide very effective shielding be tween each section. As well, when bolted in position underneath the chassis, the unit is held rigidly in place, ensuring freedom from fre quency drift. The one objective in the design of the coil unit has obviously been to maintain highest possible efficiency throughout. For example, the fifteen coils-three sets of five-are all wound on Trolitul formers, while Tro litul air dielectric trimmers are u3ed. Particular attention has also been paid to the coverage of each band to ensure the most favourable possible L/C ratio. Band coverage is as follows:- Band Coverage 10 metres 30 m.c. to 11 m.c. 20 16 5.5 " 40 " 8 " " 3.25 " 80 4 ,, ,, 1500 k.c. B.C. 1600 ,, 550 k.c. The ample overlap that has been provided is apparent from the figures quoted above. AMPING -- motoring - C yachting - picnicking - Alignment Is Simple. wherever you go, whatever The coil unit i.3 particularly simple you do outdoors this summer, to align, because no padding is requir TAKE A 1.4 VOLT PORT ed on the highest frequency band, ABLE RADIO ALONG! The while fixed padding is provided on perfect outdoor companion for sunny days, it brings you the next two. On the two lowest fre fun and music wherever you quency bands variable padding is in happen to be-at the click of corporated, and to obtain perfect a switch. Light, compact, re alignment all that is necessary here quiring no .earth or aerial, is to adjust the padder on each band you can carry and use it any vvhere - and being entirely to give correct tracking with the cali self-contained (powered w ith brated dial. The tuning condenser dep.endable Eveready Dry specified i3 a Stromberg-Carlson "ll" Batteries) there is no ac type, with three 35 mmfd. midget cumulator to recharge, no variables paralleled across it for ver outside plug or power point nier tuning and to spread the "ham" to bother about. Ask your radio dealer to demonstrate bands. one of the latest models. Exceptionally High-Gain I.F.'s. The receiver illustrated incorporat : s a two-stage i.f. amplifier using three permeability-tuned iron-cored u. transformers. A striking feature of these is the enormous gain it is pos sible to obtain from them, with com plete stability. For example, the measured sensitivity of the i.f. chan nel in the "World-Cruiser Communica tions Eight" is 6 microvolts, but des pite this exceptionally high gain there is not the slightest trace of instabil ity present. Fracfional microvolt sensitivity is given by the receiver on all bands ex cept around ten metres, where the sensitivity is a trifle over 1 microvolt. This means that there will always be a tremendous reserve of power avail able if required, though it will be The Australasian Radio World, February I, 1940. Page .15 SYHJ COi L BOX TO GRID OF 6B6(j --+Mt--br:~ 0c11 Yel. & Bo~ -Hl!iblclllll I ------' FOR 5HAFT FOR 5HAFT 0 0 OF COIL BOX OF BAND- 5PREADE.R5 When the receiver is being built, the wiring should first be completed to the stage shown above. Lastly, the coil unit should be bolted in place and wired in accordance with the sketch shown el5ewhere. found that it is rarely, if ever, neces Well-Planned Layout. Next follows a two-stage i.f. am sary to operate the receiver "full out." The layout of the "World-Cruiser" plifier using a pair of 6U7G's, the was decided upon after careful con cathodes of these being tied together Directly-Calibrated Dial. sideration of all factors involved, and and returned to earth via a 200-ohm The special dial developed by R.C.S. should not be altered in any way. A bias reBistor and 5,000 ohm potentio Radio for use with the coil unit is particularly important point is that meter, which acts as the i.f. sensitiv directly calibrated on all five bands, the beat frequency oscillator is locat ity centrol. The second detector is a the scale being etched into the glass. ed well away from all r.f. and i lf. 6B6G, one diode being used for half The dial itself has a particularly circuits, to obviate any possibility of wave detection and the other to pro smooth friction type drive which is unwanted coupling· vide a.v.c., which is applied to the four fully adjustable, thus obviating all preceding valves. The triode section Circuit Fol101ws Latest Trends. chance of slipping. of the 6B6G acts as audio driver, driv The circuit of the "World-Cruiser" ing a 6F6G output pentode. The beat The beat frequency oscillator is a is standard throughout, but at the frequency oscillator is a 76, and the 76, an R.C.S. b·f.o. unit being used same time is in accordance with lat rectifier, a 5Y3G. with it. The special tapped coil re est trends in communications receivers. The seven controls along the front quired, with mica condenser across it, The valve line up is as follows: wall of the chassis shown in the view and the 50,000 ohm grid leak and A 6U7G tuned r.f. stage provides above are (left to right) b.f.o. note .0001 mfd. grid condenser are all en tuned image suppression and ensures ' control, b·f.o. switch, bandspread con closed in the can as indicated by the a very favourable signal-to-noise trol, band switch, tone control, i.f. dotted line on the circuit diagram. A ratio. It is followed by a 6K8G · sensitivity control and gain control. variable 2-plate midget condenser mixer. The oscillator section of the provides a variable pitch control, c0il unit was designed around this Assembly Is Straight-Forward. while the single-pole/single-throw valve, and no other type can be used , Until now the construction of a switch across it enables the beat fre here. Over all bands the grid current receiver of this type has generally quency oscillator to be cut in and out of the 6K8G is maintained wifoia the been regarded, and rightly so, as a of cir'cui t at will. :rated limits, even down on 10 metres. (Continued on page 25) Page 16 The Australas.ian Radio World, February I, 1940. World Short"7ave Stations Below are listed the principal shortwave stations of the world, the majority of which are audible in Australia and/or New Zealand at the present time. The latest available schedules are given in Australian Eastern Standard Time. The addresses of the stations which were listed in the October, 1939, issue, are not repeated; readers should refer to the issue mentio1'ed. In the case of new stations full addresses are given. Compiled by ALAN H. GRAHAM. Call K.C. Metres Location. Schedule, etc. W4XA 26150 11.47 Nashville, Tenn., U.S.A. Daily 2-4 a.m.; 8.30 a.m.-2 p.m. W9XJL 26100 11.49 Superior, Wis., U.S.A. Addr: Head of the Lakes Broadcasting Co . Daily 1-11 a.m. W8XNU 25950 11.56 Cincinnati, Ohio, U.S.A. Daily 10 p.m.-4 p.m. W9XPD 25900 11.58 St. Louis, Mo., U.S.A. Addr.: St. Louis Post-Dispatch. Daily--exact schedule unknown. w1;nx 21570 13.91 New York City, U.S.A. Daily 11 p.m.-3.30 a.m. GST 21550 13.92 Daventry, England. Daily 8.40 p.m.-12.15 a.m. WPIT 21540 13.93 Pittsburgh, Pa., TJ .S.A. Daily 8.30 p.m.-midnight. GSJ 21530 13.93 Daventry, England. Daily 8.40-11.45 p.m. 2R0-16 21510 13.94 Rome, Italy. Daily 12.05-12.55 a.m. GSH 21470 13.97 Daventry, England. Daily 8.40-11.45 p.m. DJS 21450 13.98 Berlin, Germany. Not in use at present. DJH 17845 16.81 Berlin, Germany. Daily 5.30 p.m.-12.30 a.m. WCBX 17830 16,83 New York City, U.S.A. Not in use at present. 2R0-8 17820 16.84 Rome, Italy. Daily 8 a.m.-noou; 9-10.25 p.m. GSV 17810 16.84 Daventry, Eng-land. Daily 8.40-10 p.m.; midnight-2.30 a .m. OIH 17800 16.85 Lahti, Finland. Addr.: Finnish Broadcasting Co., Felsinki. Daily 7 p.m.- midnight. GSG 17790 16.86 Daventrv, England. Daily 8.40-11.45 p.m. WNBI 17780 16.87 Bound Brook, N.J., U.S.A. Daily midnight-11 a.m. PHl-2 17770 16.88 Huizen, Ho.Jland. Daily except Sunday, 10,40 p.m.-midnight; Sundays, 9.40 p.m.-1.05 a.m. TPB-3 1776'5 16.88 Paris, France. Daily 7 p.m.-midnight. DJE 17760 16.89 Berlin, Germanv. Daily 5.30-8.50 p.m.; 9-11 p.m. RV-96 15400 19 47 Moscow, U.S.S.R. Daily 7-10 p.m.; irregular at other times. HAS-3 15370 19.52 Budapest, Hungary. Sunday midnight-Monday 1 a.m. D.TR 15340 19.56 Berlin, Germanv. Daily 3.05 p.m.-2 a.m. WGEA 15330 19.!l7 8chenectadv, N.Y .• U.S.A. Daily 2.15-9 a.m. KGEI 15330 19.57 San FranciRco. Calif., U.S.A. Daily 9.30 a.m.-2.15 p.m. GSP 15310 19.60 Daventry, Eng-land. Daily 4.35-6.30 a.m.; 5-'8 p.m. YDB 15310 19.60 Bandoeng. Java, D.E.I. Addr.: N.I.R.O.M. Daily 1.30-5 p.m. 2R0-6 15300 19.61 Rome, Italy. Daily 1-8.55 a.m.; 10.30 a.m.-12.30 p.m.; 7.10-7.55 p.m. VUD-3 15290 19.62 Delhi, India. Daily noon-2 p.m.; 4.30-6.30 p.m. UJQ 15280 19.63 Berlin, Germany. Daily 3.05 p.m.-2 a.m.; also 2.10-3.25 a.m. on Mondays. WCAB 15270 19.64 Philadelphia, Pa .. U.S.A. Addr.: C.B.S., 485 Madison Avenue, New York City. Daily 3 or 3.R0-8.15 a.m. WCBX 15270 19.64 New York City, U.S.A. Daily 4-6.. 30 a.m. GSI 1!5260 19.66 Daventry, England. Daily 3-4.30 a.m.; 3.57-8 p.m. 'T'PA-2 1~24!) 19.68 Paris, France. Daily 7 p.m.-midnight. 2R0-14 15230 19.70 Rome, Italv. Daily 1-3.15 a.m.; 3.40-8.30 a.m.; 8 ..30-11.10 p.m. OLR5A 15230 19.70 Prague, Bohemia. Daily 10.55 a.m.-1.20 p.m.; 7.5-5-11.15 p.m. PCJ-2 15220 19.71 Huizen, Holland. Daily, except Sunday, 10.40 p.m.-12.10 a.rn.; Sundays, 9.25 p.m.-12.45 a.m. CSW-4 15215 19.71 Lisbon, Portugal. Daily 2-3 a.m. WPIT 15210 19.72 Pittsburgh, Pa., U.S.A. Daily midnight-5 a.m. DJB 15200 19.74 Berlin, Germany. Daily 11 p.m.-midnight; also 2.10-3.25 a.m. on Mondays. XGOX 15190 19.75 Szechwan Province, China. Irregular; usually around 7-8 p.m. OIE 15190 19.75 Lahti, Finland. Address: Finnish Broadcasting Co., Helsinki. DaHy mid night-8 a.rn. GSO 15180 19.76 Daventry, England. Exact hours of transmission not known; heard early morn- ing and evening. RV-96 1!ll80 19.76 Moscow, U.S.S.R. Daily 3.45-6.45 p.m.; 7-10 p.m. TGWA 15170 19.77 Guatemala City, Guatemala. Mondays 3.45-8.1.S a.m.; also on alternate Sundays till · ~ <'r\'t'"',\~~. {I " ' 5.15 p.m. LKV 15166 19.77 Oslo, Norway. Daily 9.40 p.m.-5 a.m. JZK 15160 19.79 Tokyo, Japan. Daily 7.30-8.30 a.m.; 11 a.m.-noon. SBT 15155 19.79 Motala, Sweden. Address: Direction Generale des Telegraphes Suede, Stock holm. Daily 4-7.15 a.m.; Sundays from 5.55 p.m. YDC 15150 19.80 Bandoeng, Java, D.E.I. Daily 9-10.30 a.m.; 7.30 p.m.-1.30 a.m. The Australasia.n Radio World, February 1, 1940, Page 17 Call K.C. Metres LocaHon. Schedule, etc. GSF 15140 19.82 Daventry, England. Daily 6.50-9 a.m.; 6.30-8 p.m.; 11.55 p.m.-2.30 a.m. WRUW 15130 19.83 Boston, Mass., U . .C:.A. Address: University Club. Daily 5.30-8 a.m. TPB-6 15130 19.83 Paris, Franc2. Daily 3-6 p.m. HVJ 15120 19.84 Vatican City, Italy. Exact schedule unknown; heard from 11.30 p.m. on Tues- days; and 1.30-1.45 a.m. daily. D.JL 15110 19.85 Berlin, Germany. Daily 1.40-7.25 a.m.; ·3. 05-5 p.m. 2RO-l2 15100 19.87 Rome, Italy. Daily 3.15-8.30 a.m.; 8.30-11.10 p.m. . RKI 15083 rn 89 Moscow, U.S.S.R. Daily 10 a.m.-12.15 p.m; and irregular at other times. KQH 14920 20.11 Kahuku, Hawaii. Relays to U.S.A.; Saturdays noon-1 p.m., 5-5.30 p.m.; Sundays 2-2.30 p.m. HBJ 14535 20.6·1 Geneva, Switzerland. Address: Radio Nations. Heard 6.30 p.m. Sundays. KKZ 13690 21.91 Bolinas, Calif., U.S.A. Special relays to Hawaii; Sunday afternoons. HilN 12486 24.03 TrujHlo City, D.R. Daily 8.10 a.m.-1.10 p.m.; 9.40 p.m.- 1.40 a.m. HCJB 12460 24.08 Quito, Ecuador. Daily 1-2 p.m.; 10-11.15 p.m. RNE 12000 25.00 Moscow, U.S.S.R. Dailv 2-7 a.m.; 3.45-6.45 p.m.; Mondays 1-2 a.m.; Mon .days, Tuesdays 7-8 a.rn.; Wedne5days, 9.30-10 p.m.; Sundays 9-10 p.m. \Varsaw 11990 25.02 Warsaw, Pohnd. CB-1180 Daily 7 p.m.-midnight. 11970 25.06 Santiago, Chile. Daily 10 a.m.-2 p .m. KKQ 11950 25.10 Bolinas, Calif., U.S.A. Special relays to Hawaii; irregular afternoons. CD-1190 11910 25.19 Valdivia, Chile. Daily 1-4 a.m.; 6-9 a.m.; 10 a.m.-2 or 2.30 p.m. XGOY 11900 25.21 Szechwan Province, China. Daily 5-.9.30 a.m.; 8.30 p.m.-1.30 a.m. TPB-11 11885 25.24 Paris, France. Daily 12.15-7.15 a.m.; 3-6 p.m. TPB-12 11885 2'5.24 Paris, France. Daily 9-11.15 a.m.; 11.30 a .m.-2 p.m. VLR-3 11880 25.25 Lvndhurst, Australia. Daily 6.30 a.m.-5.15 p.m. WPIT 11870 25.26 Pittsburgh, Pa .. U.S.A. Daily 5 a.m.-2 p.m. VLQ-2 11870 25.26 Sydney, Aus•ralia. Daily 5.30-6.·30 p.m. GSE 11860 25.29 Daventry, England. Daily 9.22 a.m.-12.15 p.m.; 6.30-8 p.m. "WORLD-CRUISER COMMUNICATIONS HYDRA METAL CASED BLOCK EIGHT." CONDENSERS. Use the R.C.S. Foundation Kit Type K124 ...... £13/13/9 . 2S mfd . SOOY. Test 6d. each. 4/- doz. Comprising- mfd . ! x DA2 S-band dial ...... 22/6d. .s SOOY. Test 9d. each. 6/- doz. mfd . 2 x IFI 31 permeability 1.F.'s ...... 13/9d. each .s 700V. Test 9d. each. 6/- doz. mfd. 1 x IFI 32 permeability 1.F.'s ...... 13/9d. each 3 x .s 700V. Test 1/6 each. 12/- doz. 2 x .1 mfd. 1 x DW30 S-band coil unit ...... £10/10/- 2000V. Test 9d. each. 6/- doz. Write f0 1· our special complete kit of part quotes. A.W.A. SHORT WAVE AERIAL KITS-Improve the reception R.C.S,. NEW PRICE LIST. POST FREE. of overseas radio by installing one of the latest A.W.A. SEND TO-DAY FOR A COPY. Aerial Kits ...... ';7 /6d. each. 490 Elizabeth Street, 168 and 243 Swanston Street, Melbourne; 299 Chapel Street, Prahran; S Riversdale Road, Co1nberwell; 99 Puckle Street, Moonee Ponds. All letters to BOX 213ST, G.P.O., MELBOURNE. VEALLS Telegrams: "ARTVEALL," MELBOURNE." Page 18 The Australasian Rodi:- World, February 1, 1940. Cail K.c. Metres Location. Schedule, etc. DJP 11855 25.31 Berlin, Germany. Not in use at pre::;ent. XMHA 11850 25.32 Shanghai, Chba. Daily 8 p.m.-1.80 a.rn. WCBX 11830 25.36 New York City, U.S.A. Daily 7-9 a.rn.; 9.30 a.rn.-1 p.rn. VLW-3 11830 25.36 Perth, Australia. Daily 3.30-4.30 p.rn. 2R0-4 11810 2540 Rome, Italy. Daily 1-6 a.rn.; 9 a.m.-noon; 7.10 p.m.-midnight. DJZ 11801 25.4.2 Berlin, Germanr Not used at present. COGF 11800 25.42 Matanzas, Cuba. Daily 4-5 a.rri~; 7-8 a.m.; 9 a.rn.-3 p.rn. JZJ 11800 25.42 Tokyo, Japan. Daily 7.30-8.30 a.rn.; 3-4.30 p.rn.; 10 p.rn.-12.30 a.rn. WRUL 11790 25.45 Boston, Mass., U.S.A. Heard in early mornings; schedule unknown. Saigon 11780 25.47 Saigon, French lndo-China. Daily 8.45-11.30 p .rn. J\'ITCY 11775 25.48 Hsinking", Manchukun. Address: 601 Daido-Taigai, Hsinking. Daily 7-7.50 a.rn. UJD 11770 25.49 Berlin, Germany. Daily 1.40-7.25 a.rn.; 7.50 a.rn.-1.50 p.rn. 2R0-15 11760 25 51 Rome, Italy. Daily 1-3.15 a.rn. GSD 11750 25.53 Daventry, England. Daily 2.52-6.80 a.rn.; 6.-50-9 a.m.; 12 .. 37-3.20 p.m.; 3.57- 1 6.15 p.rn. LKQ 11735 25.57 Oslo, Norway. Address: Norsk Rikskringkasting Storingsgaten 28. Daily 2-5 a.m.; 5-9.40 p.m. WRUW 11730 23.58 Boston, Mass., U.S.A. Schedule uncertain; heard till 8 a .m . C.JRX 11720 25.60 Winnipeg, Canada. Daily 9 p.rn.-3 p.m.; Sundays till 7 p .m. JVW-3 11720 2S.60 Tokyo, Japan. Daily 4.50-10.40 p.rn. TPA-4 11715 25.61 Paris, France. Daily 9-11.15 a.m.; 12.3'0-3 p.m.; 3-6 p.m. JLG-3 11705 25 .63 Tokyo, Japan. Daily 5-7 a.m.; and at night from 7 p.m. SEP 11705 25 .63 Motala, Sweden. Daily 4-7.15 a.m.; 11 a.m.-noon on Thursday and Saturday. HP5A 11700 25.65 Panama City, Panama. Daily 2.45-4 a.m.; 9 a.m.-1 p.m.; 10-11.30 p.m. CB-1170 11700 25.65 Santiago, Chile. Daily 1.5 a.m.; 6.30 a.m.-2 p.m. IQY 11676 25.70 Rome, Italy. Daily 3.07-3 .. 56 a.m.; 4.50-5.30 a.m.; 8.20-8.40 p.m. XGOK 11650 25.75 Canton, China. Daily till 11.35 p.m. HBO 11402 26.31 Geneva, Switzerland. Schedule unknown; heard 6.30 p.m. Sundays. Address, se() HBJ, 14535kc. C:SW-6 11040 27.17 Lisbon, Portugal. Daily 3.45-6.30 a.m. PLP 11000 27.27 Bandoeng, Java, D.E.I. Relays YDC; daily 9-10.30 a.m.; 7,.30 p.m.-1.30 a.m. EAJ-43 10360 28 96 Sant?. Cruz de Tenerife, CanaryAddress: Box 225 Daily 5.30-7 a.m.; 7.30-10 a.m.; 10.45- Is. 11.45 a.m.; noon-1 p.m. ORK 10330 29.04 RuysseledeJ Belgium. Address: Radio Ruysselede, West Flanders. Daily 4.30- 6 a.m. PMN 10260 29.24 Bandoeng, Java, D.E.I. Relays YDC; as PLP, llOOOkc. "WHEREVER SOUND MUST FILL GREAT SP ACES" ~PLIO~ PUBLIC ADDRESS 'fype P.8.25 SPEAKERS This s:x-foot Exponential Horn Speaker of ially impregnated against moisture absorp true logarithmic design o_ffers users of P.A. tton. The mechanical strength is many times The Most Efficient Speaker Equipment ~,he greatest possible efficiency, far that of a metal diaphragm and there is no in advance of cone units driving into short risk of hardening or crystallisation leading to on the Market To-day! horns. Steps up your P.A. efficiency by more ftactures. The unit is permanently trouble than 300'/o ! The Horn is unique, being the free and will carry steady loads up to IO WRITE NOW for Publica first of its type made of extra heavy gauge watts, delivering acoustic power through the sheet aluminium, the granular construction P.S.25 Horn 300% to 400% greater than tion No. 90A, telling how offering far greater strength than heavier ordinary types. The permanent magnet is of YOU can get REAL P.A. castings. Alnico alloy with the high flux of 12,000 The P.S.6 Permag. driving unit weighs 7} lines per sq. cm. Full data and Prices on results more economically! lbs. and has a non- metallic diaphragm spec- Application-ask for P.A. Publication No. 90. AMPLION (A'sia) Pty. Ltd., 382 Kent Street, SYDNEY The Australasian Radio World, February 1, 1940. Page 19 R.C.S. Announce their latest release • • • 5 BAND COIL UNIT Just what you have been waiting for-WE HAVE IT! R.C.S. DUAL WAYE UNITS R.C.S. TROLITUL TUNING COI LS R.C.S. TROLITUL MIDGET R.C.S. RADIO FREQUENCY CHOKES Type DWZ4, as illustrated, consists of Aerial, The new R.C.S. Trolitul Tuning Coils, as CONDENSERS TROLITUL TAPERE;> R.F. and Oscillator Coils, Wave Change listed and illustrated, provide the highest Q R.C.S. Midget PIE WOUND R.F. Switch, the necessary B/C and S/W Trimmers coils yet prodl.lced. They are wound on and CHOKES. and Padder mounted on a rigid steel base, supported by a combined Tro':'itul former and Condensers are These chokes are wired up ready to assemble in a set utilising base, thus lending themselves to an accuracy made in two wound on a Trolitul 46S k.c. and an R. F. Stage. The bands are and precision hitherto unobtainable, resulting types, using Tro former, the lugs and S/W 16 to SO metres, and B/C 1 SOO to SSO k.c. in ·a higher standard of etticiency than ha s mounting screw being been available before. All R.C.S. Trolil ul litul supports, moulded into the Retail Price Coils are suitable for standard type valves. thus guarantee former. The Wi!1dings ing practically no are spaced pies, DWl4 for A.C. operation ...... £3 7 6 tapering to the top. DW2S for Battery operation .. . • £3 7 6 R.C.S. TROLITUL loss. Owing to its very high insulation and DUAL- WAVE construct ion, t h is COILS M.C. Type choke is ideal tor short-wave receivers. These coils have the B/C They are made in the and S/W Trimmers in following si:res: corporated. The Oscil T h e 14-plate R.F. CHOKES, Pie lator coil also contains Wound-Trolit ul Type DW30 5-band Coil Unit for Communication Re ceivers. equals old style the S/W Padder. S/W 23-plate capac- -Pies M.H. Price 16 to SO metres, B/ C RFSZ 3 1. 7 4 / 6 1 SOO to 5SO k.c. · Continuous coverage from 9.8 to 5SO metres is provided by means of a special f;ve-bank three ity. The M .C. · RF83 4 Z.5 4/6 RF84 5 4 .0 4/6 section silver-plated contact wave-change switch. The 15 coils are wound on Trolitul and the type may be Cat. Retail ganged. RFSS 6 7.0 4/6 No. Price air dielectric trimmers are also Trolitul. The Trolit ul padders are incorporated a nd a band selector plate is provided. With a standard tuning condenser there is a 33 1 /3 % overlap of Star Type STANDARD R.F. CHOKES G 19. Aerial Air RFS 1 and RF86 are single pie wound on o Core 14/- bands. A small gang will provide Ham bands only-band spread. For the "World-Cruiser solid Trolitul core, which has t he necessary G20. R.F. Air Core 14/ Communicatiol"IS Eight" described in this issue, specify Kit Type KT 24, comprising- STAR AND M.C. MIDGETS solder lugs moulded in. The design of this Max. Min. choke eliminates the need ot bakelite side Type DW29, as illustrated, consists o_f Aerial B21. Osc. Air Core 1 'I I - 1 DA2 5-band Communications Dial ...... £1 2 6 C Page 20 The Australasian Radia World, February I, 1940. The Australasian Radia World, February I, 1940. Page 21 l\fetres Location. . Schedule, etc. ca ii itc. Tue3day, 11-11.30 a .rn.; Saturday, 10-10.30 p.m.; other PSH 10220 29.35 Rio de Janeiro, Brazil. days, 9-10 a.m. 30.24 Dairen, Manchukuo. Daily 10-11 p.m. JDY 9920 Schedule irregular at present; 6.30-8 a.m. and at other EAQ 9855 30.45 Madrid, Spain. t'.1mes. Daily 3-3.25 a.m.; 3.40-4 a.m.; 4.50-5.30 a .m.; 9 a .m.-noon; IRF 9830 30.52 Rome, Italy. 8.20-8.40 p.m. 9805 30.60 Habana, Cuba. Daily 11 p.m.-4 p.m. COCM Address: South African Broadcasting Corporation, Box ZRO 9752 30"77 Durban, South Africa. ·' 4559, Johannesburg. Heard best midnight-3.30 a.m. session. 9735 30.82 Lisbon, Portugal. Daily 7-11 a.m. CSW-7 Relays CB-76; daily 9.30 a.m.-2.30 or 3.15 p.m.; also from CB-970 9730 30.83 Valparaiso, Chile. 9.30 p.m. JlE-2 9695 30.% Tyureki, Taiwan. Relays JFAK from 11 p.m. ZHP 9690 30.96 Singapore, Malaya. Sundays 8.40 p.m.-12.40 a .m.; Wednesdays 3.40-4.40 p.m.; Monday-Friday 7.40 p.m.-12.40 a.m.; Saturday 3.25- 4.40 p.m., 7.40 p.rn.-12.40 a.m. GRX 9690 30.96 Daventry, England. Daily 6.50-9 a.m.; 9.22 a.rn.-12.15 p.m.; 3.57-8 p.m.; 8.40- 11.46 p.m. TGWA 9685 30.96 Guatemala City, Guatemala. Daily 10.30 a .rn.-3.15 p.m.; later on Sunday afternoons. XEWQ 9680 30.99 Mexico City, Mexico. Daily midnight-'3.45 p.m.; till 4 p.m. on Sundays. Paris 9680 30.99 Paris, France. Testing; afternoons as TPA4 DJX 9675 31.01 Berlin, Germany. Daily 1.40-7.25 a.m. 9670 31.03 Bound Brook, N.J., U.S.A. Daily 9 a.m.-4 p.m. WRCA Daily 3.20 a.m.-noon. 2R0-9 9665 31.04 Rome, Italy. 9660 'll.06 Manila, P.I. "The Voice of the Philippines"; daily 8 p.m.-midnight. KZRH Daily from 3.15 a.m. JLT-2 9645 31.10 Tokyo, Japan. 9636 31.13 Taihoku, Taiwan. Daily 12.05-1.30 a.m. JFO Daily 3.07 a .m.-noon; 4-5.30 p.m. 2R0-3 9635 31.13 Rome, Italy. 9620 31.19 San Jose, Costa Rica. Daily 10 p.m.-2.30 p.m. TIPG Daily 1.30'-2.30 a.m.; 5-7 p.m.; 9 ..30-11p.m.;11.15-11.45 p.m. VLQ 9615 31.20 Sydney, Australia. ZRL 9606 31.23 Klipheuval, S. Africa. Address as ZRO, 9752kc. Heard midnight-2.45 a.m. session. DXB 9605 31.23 Berlin, Germany. Daily 5-5.30 a .m.; 7-7.40 a .m.; 7.50 a .m.-1.50 p.m. RAN 9600 31.25 Moscow, U.S.S.H. Daily except Monday 9 a.m.-1 p.rn.; Monday 9-10 a .m.; 12.15-1 p.m. CB-960 9600 3L25 Santiago, Chile. Daily 10 pm.-7.30 a.m.; 10 a.m.-3 p.rn. HP5J 9590 31.28 Panama City, Panama. Da!ly 9 a.m.-1.30 p.m.; from 10 p.m. VUD-2 9590 31.28 De•lhi, India. D;u]y 1-3 p.m.; 5-7.15 p.m.; 10.30 p.m.-4 a.m. PCJ 9590 31.28 Huizen, Holland. Monday and Wednesday 5-6.35 a.m. WCAB 9590 31.28 Philadelphia, Pa., U.S.A. Tuesday, Friday, Sunday 9.'30 a.m.-5 p.m.; Thursday noon- 5 p.m. GSC 9·580 31.32 Daventry, England. Daily 2.52-4.30 a.m.; 6.50-9 a .m.; 9.22 a.rn.-12.15 p.m.; 12.37-3 30 p.m.; 3.57-4.45 p.m. VLR 9580 31.32 Lyndhurst, Australia. Daily 5.30 p.m.-midnight. KZRM 9570 31.35 Manila, P.I. Darly ·7.30-9 a.m.; 7 p.m.-1.30 a.m. WBOS 9570 3l.35 Boston, Mass., U.S.A. Daily 9 p.m.-5 p.m; Sundays from 10 p.m. RADIOKES FIRST WITH THE NEW RELEASE. Use Radiokes 5-band Coil Unit for the "Communications Eight" if you want the BEST results! 1 5-band communi ~ catlons d :al £1 z 6 2 permeab'. l ity in- termediates . . . . £ 1 7 (j 1 °0 ~ 1 permeabiLty in- termediate ... , . 13 9 1 5-band coil unit £10 10 U £13 13 9 We are Factory Representa ~.C.S. tu ]~ tives tor Radio Products. Also power transformers o:id W.W. resistors. Write to us :or ~~~~!;'!gue. Use the coupon 5-band coil unit above now available in tri-wove. r·--··------·------·------··I WINGELLO HOUSE, ANGEL PLACE, I RADIO SUPPLIERS PTY. LTD. SYDNEY. 'PHONE: B 4586, B 4557. I : Please send details of the following lines...... : Nome ...... I : Address ...... r•••••••••••••••••••••••••••••••••••••••••••W•••••••••••••••••••••••••••••••••••••L Page 22 The Austrolos.ian Radio World, February I, 1940. Call ICC. Metres Location. Schedule, etc. VLW-2 9560 31.38 Perth, Australia. Testing early a.m. XGAP 9560 31.38 Peking, China. Heard after midnight. D.JA 9560 31.38 Berlin, Germany. Daily 7.50-11 a.m.; 11 a.m.-1.50 p.m.; 3.05-5 p.m. WGEA 9550 31.41 Schenectady, N.Y., U.S.A. Daily 8.15-11.15 a.m. YDB 9550 31.41 Bandoeng, Java, D.E.I. Daily 7.30 p.m.-1.30 a.rn. DJN 9540 31.45 Berlin, Germany. Daily 3-7 a.m.; 3.05 p.m.-2 a .m. JZI 9535 31.46 Tokyo, Japan. Daily -5-7 am.; 10 p.m.-12.30 a.rn. KGEI 9530 31.48 San Franci£co, Calif., U.S.A. Daily 3-6 pm.; 10 p.m.-1 a.m. WGEO 9530 31.48 Schenectady, N.Y., U.S.A. Daily 6 a.m.-2.4G p.m. ZBW-3 9526 31.49 Hong Kong. Daily 7 p.m.-1 a.m. RY-96 9520 31.51 Moscow, U.S.S.R. Daily midnight-7 a.rn.; 7-10 p.rn.; Sundays 8-9 a.m. YUA 9507 31:56 Belgrade, Yugo-Slavia. Daily 3-9 a.m. GSB 9510 31.55 Daventry, England. Daily 4.45-6.30 a.m.; G.50-9 a.rn.; 9.22 a.m.-12.15 p.m.; 12.-37-3.30 p.m.; 3.57-G.15 p.m.; midnight-2.30 a.rn. XEWW 9503 31.57 Mexico City, Mexico. Daily midnight-2 a.m.; 3-5 p.m. KZIB 9197 31.'19 Manila, P.I. Daily 7 p.m.-rnidnight. KEI 9490 31.61 Bolinas, Calif., U.S.A. Relays to Hawaii late afternoons. TAP 9t65 31.70 Ankara, Turkey. Daily 2-7.30 a .rn .; week days 8.30-10 p.rn.; Saturday 9.30- 11.30 p.m.; Sunday 8.30-10.30 p.m. COCH 9437 31.80 Habana, Cuba. Daily 11 p.m.-3 p.rn. COBC 9360 32.04 Habana, Cuba. Daily 10 p.m.-3 p.rn. OAX4J 9340 32.12 Lima, Peru. Daily 4-6 a.rn.; 8 a.rn.-4 p.m. XTC 9295 32.28 Shanghai, China. Daily 11 p.m.-midnight. CORX 9200 32 61 Habana, Cuba. Daily 11 p.m.-2.30 p.m. COBZ 9030 33.32 Habana, Cuba. Daily 10.45 p.rn.-midnight. COCQ 8830 33.98 Habana, Cuba. Daily 8.45 p.rn.-midnight; 2-3 p.m. HS8PJ 7960 37.56 Bangkok, Thailand. Irregular 11 p.m.-1 a.m. JIE 7295 41.13 Tyureki, Taiwan. Relays JFAK from 11 p.m. JLG 7285 41.19 Tokyo, Japan. Irregular; heard around 6 a .m. TPB-11 7280 ! 1 "1 Paris, France. Daily 12.15-7.15 a.m. .JVW 7257 41.34 Tokyo, Japan. Daily 5-7 a.m. GSW 7230 41.53 Daventry, England. Daily 3.57-8 p_m.; and early a.111. YDX 7220 41.55 Medan, Sumatra, D.E.I. Daily 1.30-5 p.111.; 7.30 p.m.-midnight. XPSA 7000 42 80 Kweiyang, China. Daily 9 p.m.-11.45 a.m. XO.JD 6880 43.60 Hankow, China. Daily 9-11.30 p.m. PMH 6720 4-1.64 Bandoeng, Java; D.E I. Daily 7.30 p.m.-2 or 2.30 a.m. TGWB 6490 46.20 Guatemala City, Guatemala. Daily -3.45-6.45 a rn.; 10.30 a .m.-3.15 p.m.; 10.45 p.m.- midnight. Later on Sunday afternoons. COHI 6460 46.44 Santa Clara, Cuba. Daily from 9.55 p.m. COCQ 6360 47.17 Habana, Cuba. Testing new frequency; 10 p.m. IAC 6355 47.20 Rome, Italy. Daily 6-'6.35 a.m. co cw 6324 47.40 Habana, Cuba. Daily 9.55- p.m.-3 p.m. TG-2 6190 48.47 Guatemala City, Guatemala. Tues.-Sat. 9 a.m.-2 p.m.; Sun. 9 a.m.-6 p.m.; 10 p.m.-2 a.m.; Monday 6-11 a .m. HVJ 6190 48.47 Vatican City, Italy. Daily 5-6.30 a.m. TILS 6165 48,66 San Jose. Costa Rica. Daily from 10 p.m. WPIT 6140 48.86 Pittsburgh, Pa., U.S.A. Daily 2-3 p.m. KZRF/ KZEG 6140 48.86 Manila, P.I. Daily 8 p.m.-midnight. XEXA 6133 48.90 Mexico City, Mexico. Daily 10.30 p.m.-rnidnight. VLW 6130 48.94 Perth, Australia. Testing at 9 p.m. MTCY 6125 48.98 Hsinking, Ma'lchukuo. Address: 601 Daido-Taigai, Hsinking. Daily 11.30 p.m.- 1.30 a .m. FK8AA 6122 49.00 Noumea New Caledonia. lrreg. 5.30-7 p.m. WCBX 6120 49.01 New York City, U.S.A. Daily 3-5 p.m. GSL 6110 -:l9.10 Daventry, England. Daily 9.22 a.m.-12.15 p.m.; 12.37-3.30 p.m. KZRH 6110 49.10 Manila, P.I. Daily 8 p.m.-midnight. YUA 6100 49.18 Belgrade, Yugo-Slavia. Daily 3-9.30 a.m. ZAA 6085 49.30 Tiranr• . Albania. Daily 3.20-7 a.rn. VQ7LO 6083 4!!_.31 Nairobi, Kenya. Tuesday-Saturday 2.15-5.15 a.m.; Sunday 2.15-6.15 a.m.; Monday 1.45-4.45 a.m. ZHJ 6080 49.34 Penang, Malaya. Daily 9.40-11.40 p.m. OAX4Z 6077 49.35 Lima, Peru. Daily except Monday 10 a.m.-4.30 p.rii.. YDD 6060 49.50 Bandoeng, Java, D.E.I. Daily 8,30 p.m.-1 a.m. WLWO 6060 49.50 Cincinnati, Ohio, U.S.A: Daily from 8.45 p.m.; closes at Z or 5 p.m. GSA 6060 49.50 Daventry, England: Daily 3.57-8 p.m.; 6.30-9 a.m. WDJM 6040 49.67 Miami Beach, Fla., U.S.A. Daily 1-4 p.m. KZIB 6040 49.67 Manila, P.I. Daily 7 p.m.-midnight. RV-96 6030 49.75 Moscow, U.S.S.R. Daily midnight-7 a.m. The A11str~ilasian RadiQ World, Febr11ary I, 1940, Call K.C. Metres Location. Schedule, etc. iDJC 6020 49.83 Berlin, Germany. Daily 2.30-7.25 a.m. XYZ 6007 49.94 Rangoon, Burma. Daily 9.30 p.m.-1 a.m. ZRH 6007 49.94 Roberts, Heights, South Africa.Daily 12.30-6.30 a.m. HP5K 6005 49.96 Colon, Panama. Daily 10 p.m.-midnight. ZNB 5900 50.85 Mafeking, British Bechuanaland.Daily except Monday 4-5.30 a.m. PMY 5H5 58.31 Bandoeng, Java, D.E.I. Daily 8.30 p.m.-2 a.m. VUD-18 4960 60.48 Delhi, Il).dia. Daily 10.30 p.m.-3.35 a.m. VUM-2 4920 60.98 Madras, India. Dai)y 9.30 p.m.-3.10 a.m. VUB-2 4880 61.48 Bombay, India. Daily 10.30 p.m.-3.30 a.m. VUC-2 4840 61.98 Calcutta, India. Daily 9.30-3 a.m. YDE-2 4810 62.37 Solo, Java, D.E.I. Daily 7.30 p.m.-1 a.m. RV-15 4273 70.19 Khabarovsk, U.S.S.R. Daily 4 p.m.-1 a.m. Simple 'Phone Jack Substitute. A simple substitute for a double circuit 'phone jack is shown in the accompanying sketch. The cost of material for this job amounts to nil, For the Best Results as three strips of brass ~6" wide are - - - to be found in almost every amateur's junk box. COMPLETE First of all take two strips of JON MAR KITS ET fairly heavy brass 21/2" long and 16" wide and bend to the E~~ape shown For the "WORLD CRUISER COMMUNICATIONS EIGHT," in the sketch (see "A" and "B"). Now take a piece of springy brass "1940 COMPANIONETTE THREE," "MIDGET AMPLIFIER" about 7" long and bend to the shape of "C" in sketch. Contacts "A" and "B" can now b::! bolted to the side of the cabinet, leav ing 11-i" space between contact points. Now mount arm "C" in such a pos- Five-Band Coil Unit as illustrated, and as recommended by the Terhnica! Editor, includ ed in Jonmar Kitset for "Communications Eight." Save time and money-avoid misfit components-complete to the last solder lug-no disappointments with a complete Jonmar Kitset. Post the coupon below for details! Rola. Most efficient and complete range ot "The World's Finest Sound Reproducers" shortwave gear in AYstralia, designed and set iiew high standards in fidelity of TO PL.ATE·~, constructed tor complete efficiency. reception. ~:Lt~ST ~"'.::::o.·:: ::·::-.--. ~------~Please send prices and details of the "Jon mar" Kitset for t'1e .... --·--- .. ·------..... ition that it normally touches contact ...... featured in this issue. "A." A good idea is to place a solder lug under each of the mounnng bolts; Name ...... ------.. ··-- --.. ····-·-·-··-----·-·····------...... this makes the soldering of these - Address ·-- .. ·-··-·-·--·----- ...... leads much simpler. Telegrams: "JONMAR," Sydney. Telephone: BW 3109 12 lines). Having completed that, JOlll the leads up as shown in the sketch ana the job is finished. When the 'phones E}ELE:CTRICAL [ are hung on the springy brass hook JOHN MARTI N-P.!~(0·- ~~1 R~_OI~ it will engage contact "B," bringing - . ... p.;b·s i -UPPUES - , the speaker into the circuit. With ------...-~ - - .....__ .. __ .. ------...... --. . -- ' the 'phones off the hook, the arm 116-118 CLARENCE STREET, SYDNEY. "C" will spring back into position and engage contact "A." ~------Pa9e 24 The Austrgla$iall Rc;idio World, February 1, 1940. "Worid-Cruiser Communica shown in the coii and wiring sketches, plate of the 76 to a po!nt near the tions Eight." there are three yellow leads under third i.f. transformer. Several turns neath the unit, one coming from each of flex wrapped round this lead, and (Continued from page 16) section. These pass up through the with the free end soldered to terminal job for experienced set-builders. How chassis and connect to the fixed plates 1 of "I.F.T.3," ensure ample coupling. ever, the well-spaced layout of the lugs of the gang. "World-Cruiser," combined with the The two-plate midget condenser fact that the R.C.S. coil assembly is A point that should be noted is in controls the b·f.o. note, and it will be supplied fully colour coded, making regard to the coupling arrangement found that when weak signals are it a simple matter to connect it in between the beat frequency oscillator very close to one another, a slight circuit, means that anyone who feels unit and the second detector. As the change in beat note will often make confident of completing a standard 4/.5 wiring diagram shows, a shielded lead the desired signal stand out from the dual-wave receiver satisfactorily, can is run around the chassis from the interference. be assured of building the "World Cruiser" successfully. The complete under-chassis wiring is given in a sketch accompanying this article, while an additional sketch of the coil unit shows the colour cod ing a:id the method of wiring it into the receiver, the various leads being coloured correspondingly in both diagrams. The Construction Outlined. It will be noted from the list of parts that all the components used in the "'iVorld-Cruiser" are standard, and are available anywhere. In building the set, the first parts to mount are the power transfornwr, valve, speaker and power sockets, and aerial and earth terminals. (Note that a doublet aerial can be used with this Rola. receiver if desired). Next, the heater wiring for the first seven-valves in the receiver shc'uld be Loud Speakers Alone Have put in. Then the 5Y3G rectifier soc:kct should be wired, the 8 and 16 r1fd. wet -electrolytics mounted, and the All Three Essentials wiring of the smoothing filter com pleted. From this point onward the assembly and wiring are proceeded ., To Make with systematically. Commencing at the r.f. valve socket and working through to the output pentode, com Your Portable A Success plete everything as far as possible be 8 Richness and purity of tone. fore the coil unit and three band spread condensers underneath the • High efficiency ot oll volume levels. chassis are mounted. Compactness, lightness and all-time dependability. A particularly important point is e that all earth returns should be short Rola. 5- and 6-inch permanent magnet models are the very speakers for your portable set. and direct, and should be soldered to Special magnets, moulded polyfibrous diaphragm<, special transformers, patented dustproofing and acoustic filter all combine to give these speakers vast superiority in their group. Their ab lugs spot-welded to the steel chassis. normally high efficiency makes them ideal for use in conjunction with the special 1.4-volt (Four of these can be seen in a row valves and light portable batteries with which they were designed to work. Little wonder directly behind the i.f. gain control in that the manufacturers of Australia's best portable sets have made heavy demands upon the Rola factory for supplies of these amazing ~ittle speakers. the under-chassis view). As well, all See your distributor immediately and order the speakers that will give your portable radio pig-tail components such as resistors set the professional touch, for the new 5-4 model is now available. and condensers should be located as closely as possible to the appropriate The lightest permanent magnet speaker available in Australia ...... 25/- valve socket and i·f. .transformer lugs. 5-4 Before mounting the type "H" gang Write for Specification Sheets ond Full Price List. condenser, a length of copper braid should be soldered to each wiper. Each of these passes down through a ROLA COMPANY (Aust.) PTY. LTD. hole in the chassis, and is earthed. The Boulevard, Richmond, E. 1, Vic. 116 Clarence St., SYDNEY, N.S.W. This is a particularly important point, New Zealand representative: and should not be overlooked. SWAN ELECTRIC COMPANY, LTD., High Street, Auckland. In addition to the coloured leads The Australasian Radia Warld, February 1, 1940. Page 2$ <>O 't ·CJ L ....."_ . - The R.C.S. type DW30 five-band coil assembly used in the "World-Cruiser." After the assembly and wiring have been completely and thoroughly checked, the dial can be mounted, valves plugged in and the control knobs and valve shields fitted. Next, plug in the speaker and connect the aerial and earth leads. Then turn the waveband indicator to broadcast and switch on. At the same time watch the rectifier closely for any signs of flashes or of a blue glow. either of which denote serious overload due to an error in w1rmg. If, however, the Radiotrons stand out in valves light up and a faint hum is heard coming from the speaker, then popularity with radio the two gain controls can be rotated owners and broadcasting (Continued on page 28) engineers as the most de This sketch of the 'coil unit shows the penda~le and best known colour-coded leads, which are marked correspondingly on the wiring diagram. radio valve. The three yellow leads on the right of the unit col'!nect to the three band spreaders. Three additional yellow leads will be found underneath the unit. These pass up through the chassis to the three "-,...... ,,1'.r~·--.... _..../ sections of the condens.er gang. ~t.tewid Advt. of Amalgamated Wireless Valve Co. Ply. Ltd. To Destroy 1 f· "TONE BOGEY" ' i Re-valve with 1R . RADIOTRONS 1 The valves in the sealed cartons I "\,~· This photo shows how the completed receiver s.hou!d appear from underneath. Page 26 The Australasian Radio World, February I, 1940. The views on this page show a few of the dozens of instruments of all types in the lavishly-equipped R.C.S. design laboratory. The Story Of R.C.S. Radio (3) This month's insta,fment stresses the importance of design in component manufacture, and describes the several thousand pounds' worth of equip ment in the R. C. S. design laboratory. N the manufacture of radio com ing "Q" values of all r·f. components on this instrument by comparing them I ponents, design is of course of vital as well as inductance, capacity, etc. with a standard coil. The first section importance. Many of the parts Range is from 50 k.c. to 50 m.c.; ac of the tester is a pre-set oscillator, manufactured by }{.C.S. Radio are curacy within +- 1.5%. which will automatically measure the produced in hundreds of thousands, Cathode Ray Oscii'loscop·e: This in coupling between primary and sec and slip-shod design in a sing]~ lin~ strument is used mainly for fidelity ondary windings of coils, and also in could prove very costly, both as re measurements on audio transformers dicate phasing of windings. The out gards wastage of raw material an:! in conjunction with a General Radio put of this oscillator beats with a Joss of goodwill among purchasers. beat frequency oscillator. Is also variable oscillator and the resultant For this reason the company has used for general circuit analysis. built up over a period of years what beat is fed through an audio channel must be one of the finest design Matching Oscillator - Beat Fre into an output meter. By this nieans laboratories in the Commonwealth. In quency Type: Coils are check matched coils may be matched with an accur- all, several thousands of pounds h The Australasian Radio World, February 1, 1940. Page 27 acy of perhaps 10 cycies + or -. + - • Intermediate Frequency Trans "World Cruiser Communica 2 .01 mfd. tubular I Du con J. former Tester: This instrument util 2 .05 mfd. tubular I DuconJ. tions Eight." I 0 . I mfd. tubular I Ducan J. ises a frequency-modulated oscillator I .5 mfd. tubular (Ducan). and oscilloscope in conjunction with LIST OF PARTS. 2 25 mfd. dry electrolytics, 25v. wo1kin3 ( T.C.C., Ducon J. an output meter· The intermediates 5-band 9.8 to 550-metre coil unit, type 8 mfd. wet electrolytic, 500v. work are plugged into a standard i.f. chan DW30 with band indicator ( R.C.S. ) . ing I T.C.C., Ducon I. 3 permeability tuned iron-cored i.t. 16 mfd. wet electrolytic, 500v. work nel, and a direct measure of gain can transformers, 2 type IFl31, I type ing I T.C.C., Ducan I. be ascertained. The oscilloscope shows IF132 (R.C.S. I. beat frequency oscillator coil un:t , type FIXED RESISTORS : a comparative selectivity curve. F96 ( R.C.S. I . I 200 ohm 1-watt carbon 11.R.C.J . 5-band d:rectly calibrated dial and 2 300 ohm I -watt carbon 11.R.C. J. Vibrator Tester: This instrument escutcheon, type DA2 ( R.C.S.). 1 450 ohm 1-watt carbon I l.R.C. J. has two receivers with a sensitivity of 3-gang condenser I Stromberg-Carlson 1 3,000 ohm 1-watt carbon 11.R.C. I. under 1 microvolt, using dummy aer type H I. 1 10,000 ohm 1-watt carbon ( l.R.C.J. 7 octal, I 5 -pin, I 4-pin valve sockets. 1 25,000 ohm 1-watt carbon I l.R.C.1. iais. One receiver uses directly 6 valve shields. 5 50,000 ohm I -watt carbon 11.R.C.). heated and the other, indirectly I 16-gauge steel chassis, 20" x 12" x 3" 3 I 00,000 ohm I -watt carbon 11.R.C. ). I Acorn). 2 .25 megohm 1 -wait carbon 11.R.C. J . heated valves. Input voltages of 2-32 3 terminals (2 red, I black). 2 .~ megohm 1-watt carbon l ~ . R . C. I. volts can be switched to the innut 3 35 mmtd. double spaced midget vari 1 I megohm 1 - watt carbon I l.R.C. ). terminals. Measurements recorded ables for ganging ( R.C.S., Raymart) . VALVES: 2-plate mldget variable (R.C.S., Ray ~ 6U7G, 1 6K8G, 1 6B6G, I 76, 1 are input voltage, input current and martl . 6F6G, I 5Y3G. output voltage under fixed loads. power transformer, 3 85 volts, centre tap, 385v.; 100 mills., 5v. 3c., 6.3v. SPEAKER : 11 Weston Output Meter: This is used 3a., 6.3v. 2a. (Radiokesl . 8 1 10" or 12" speaker, 2,50J ohm in conjunction with the generator for I 5,000 ohm potentiometer I R.C.5.1. field, input transformer to match single 2 .5 megohm potentiometers ( l.R.C.1 . 6F6G !Rola, Amptionl . plotting sensitivity and selec:i\'ity I rotary type on/off switch. MISCELLANEOUS: cun'·~S and for taking a.v.c. m~a s u r:; 2 2" 0-100 degree indicator plates IRaymartl . 7 knobs; I indicator knob; 5 grid clips; ments, etc. 4 6.3v. d ial lights; 2 couplers tor gang FIXED CONDENSERS: ing band spreaaers; feng~ o~ power Wheatstone Bridge: Measures r e I .00006 mfd. mica !T.C.C. J. cable and plug; length ol tinned cop sistance to 10,000 ohms. Indicate3 I .00005 mfd. mica IT.C.C.J. per braid for shielding; solid and tlex ·I .00025 mfd. mica I TC.C. J. ible push-back; nuts and bolts; solder percentage error + or - 10%. I .0001 mfd. mica IT.C.C.J tags; spacers; H5ga. tinnea copper Resistance Checker: This is a bridge 2 .004 mtd. mica IT.C.C.J. wire. type instrument, providing indication of percentage error + or - 10% against fixed values. "World-Cruiser Communications OU'fPUT METER FOR "RADIO Coil Checker : Measures coupling Eight." WORLD" SERVICE OSCIL and phasing of primary and' second (Continued from page 26). LATOR. ary of coils. almost full on, and the tuning control Matching "Q" Meter: This instru rotated. Full Description Next Month. ment is a switched frequency all-wave To check the broadcast alignment, "Q" meter giving a comparative read tune in a station on approximately In next month's issue of "Rodia ing of "Q" of coils against a standard. 1400 k.c. and adjust aerial and r.f\ World" full constructional details will Flash Tester: Supplies test voltagzs broadcast trimmers for best response. appear of the output meter illustrated up to 3,000 volts a.c. for breakdown Next, swing over to a station of below. It was designed as a com and leakage testing. known frequency near the other end panion instrument to the "Radio World" of the dial and adjust the broadcast Service Oscillator described last month, Flash Tester: Similar to preceding and builders of the latter will find it in type, but only has a maximum of 600 padder until the transmission comes valuable, for while alignment of re volts a.c. in at the correct dial setting. ceivers by ear using a service oscillator This process is repeated for the 80- Potentiometer Checker: Comprises is fairly accurate, to obtain maximum metre band, which is the only other a high-speed meter which measures possible· gain from tuned circuits, the use band provided with a variable padder· of an output meter is essential. resistance of potentiometer and showa With the other three bands, stations up any open cir cuits or "jumps" dur on known frequencies are tuned in, ing rotation. and the oscillator trimmer adjusted if Comparative Resistance Tester. necessary in each case' to bring the Voltage dividers and resistors may be station in at the correct dial setting. checked against standard with this Finally, the aerial and r.f. trimmers instrument. are "touched up" at the high fre Matching Oscillator, T·P.T.G. Type: quency end in each case, and the Used for auxiliary checking of coils, alignment is complete. etc. While adjustments are being made Multimeter, B.S.1 Rating: Measures the volume should be kept well down a.c./d.c . voltage, current, ohms, and both to prevent the a .v.c. from com can be used as a valve tester in con ing into action and to enable slight junction with suitable test volta~·es. changes in volume to be noted more Inductance Capacity Bridge: Thi3 readily. instrument will measure accurately While alignment by ear is quite capacity up to .01 mfd. and inductance satisfactory for all ordinary purposes, to 100 henries. the use of a r eliable service oscillator is strongly r ecommended to ensure (To be continued next month). maximum performance. Page 28 The Au$trqla$ian RqdiQ World, Fel;iruary 1, 1940, 1940 R.C.S. Catalogue: New Factory Representative. A monthly review of latest relooses R.C.S. Radio Pty. Ltd. announce in sets, kit-sets and components that their new 1940 catalogue is now ready for distribution. Printed on high-grade paper and well-illustrated capacity coupled ~tage is the subject "B" current supply, and the 5Y3G is throughout, it contains complete de of an analysis contained in "Radio thus ample for the purpose. tails of the dozens of up-to-date lines tronics" No. 101, issued by A.W. Main chiiracteristics are also given marketed under the R.G.S. brand. Valve Go. Pty. Ltd. of the Radiotron 1Q5GT (a 1.4-volt Readers can obtain copies free from beam power amplifier), the 3Q5GT any R.C.S. distributor, or direct from Further articles deal with a filter (a battery beam power amplifier R.C.S. Radio Pty. Ltd., 50 Glebe St., for bass boosting in pick-up repro which may be arranged with the fila Glebe. duction (necessitated by attenuation ments either in parallel-1.4-volt .1 The introduction of Trolitul a year deliberately introduced during the amp.-or in series-2.8 volt .05 amp.), ago has been a very large contribut recording process), and the use of 1.4- the 6AG7 video beam power tetrode ing factor to the heavy increase in volt valves in battery/a.c. receivers. (a heater-cathode type metal valve in business enjoyed by R.C.S. lfadio dur In the latter article it is suggested tended for use primarily in the output ing the past twelve months. This has that a Radiotron 5Y3G rectifier is capable ·Of giving a d.c. output cur stage of the video amplifier of tele necessitated increasing store facilities vision receivers. so that a stock of every line produced rent of 125 m.a., which is sufficient can be built up, from which immedi for a filament current of .1 amp. to Tentative characteristics and rat ate deliveries can be made. gether with a "B" supply current not ings are also given of Radiotron trans New Factory Representative exceeding 25 m.a. Most 1.4-volt valve mitting valves, types 811, 812, 893, Appointed. receivers do not require such a high 899 and 828. Also the sales organisation is be ing augmented by the appointment of Mr. R. K. Stokes as a factory repre sentative. This appointment does not affect the existing selling organisa tion, and Mr. F. E. Wodell, Sales New 5 11 & 7" Amplions Manager, will continue to do his usual round of the trade. Entirely New Design Incorporates Rola Still Receiving* Fire- Damaged Speakers. Many Striking Features Whsn the disastrous bushfires swept Victoria months ago, Rola offered to L AST month three sample speakers The new models are novel in ap repair free of charge all speakers from the 1940 Amplion range pearance, constructional methods haY damaged in the fires. Shortly after -.vere received from Messrs. Arnplion ing been completely revised, giving the offer was made speakers damaged (Australasia) Pty. Ltd., 382 Kent St., an outstandingly different type of in various ways came to hand from Sydney. These comprise the 5E7 and speaker. The housing departs from the all parts of the devastated areas. 7E12 electro dynamics, and a 7P14 usual circular shape to advantage, the Even after the fires had become a permanent magnet model. four corner projections with mount ing holes, as shown in the accompany matter of history, speakers continued Features Of New Speakers. to arrive, and only last week a claim ing photographs, being provided for was made from Woods Point. The Main features of these new types mounting purposes. This enables the owner, whose home had been destroy can be summarised as follows:- actual rim of the cone (neglecting the ed, brought in an old rusted speaker ( 1) New housing design, giving in corrugations) to be reduced in width which had apparently been lying in creased effective cone area. to barely an §," with the nett result debris throughout the winter. After (2) Excellent power-handling cap that the effective cone area is kept Rola had verified the authenticity of acity and fidelity of reproduction. large despite the small overall dimen sions of the unit. For example, the the claim, the old irreparable speaker (3) Projection welded construction. was replaced with one of a new, effective diameter of the new 5" cone ( 4) Adjustable, concentric centre modern type. is 4," representing an increase of a ing device. radiating surface of 30% over earlier ( 5) Completely dust-proofed air Amplion models. In Latest "Radiotronics* ." gap assembly. On the 7" model also this new type Attenuation due to the grid ( 6.) Impregnated and insulated of housing gives a corresponding in coupling condenser in a resistance transformers. crease in the sound radiating area. The Australasian Rodia World, February l, 1940. l _ - Page 29 the possibiiity of electrolysis and pos Left: The new sible breakdown is removed. Amplion 7" elec Since the impedance at 400 cycles tro magnet type of both the 5- and 7-inch speakers is 7El2 model. 3 ohms, the same series of "XA" transformers can be used for either Right: The lat speake;:. est Amplion 5" electro magnet Connections To Speakers. speaker type 5E7. (a) The 5" speaker is supplied with short leads from the audio trans former and the field coil. (b) The 7" speakers can be sup- plied with either- troubles are reduced to a mmmmm ( 1) Short leads. In the 5E7, the cone assembly is should the cone ever need re-centring. (2) Cable and plugs. robust enough to handle comfortably (3) Five-point terminal block The corrugated suspensions of the 5" the power output from small receiv and 7" are similar, but each has, been with cover. ers, though at the same time sensitiv designed to give optimum results in (4) Five-pin socket and plug. ity has been kept high, with particu its particular application. · A tabulated set of important details larly good tonal balance. In both this concerning the loud-speakers of both model and the 7" 7E12, the cone has In the 7''. models, complete dust sizes and types is given below. been scientifically shaded and treated proofing has been achieved by wool to retain good high-frequency res felt washers. ponse, and at the same time to extend Radio Suppliers* Pty. Ltd. Now bass response to a degree· unobtain New Hermetically-Sealed Factory Reps. for R.C.S. able in· earlier models; Transformer. In both 5- and 7-inch speakers the Information is to hand that Radio A new transformer known as the metal .t>arts are projection welded. Suppliers Pty. Ltd. (managing direc Type XA has been developed for both Thus the housing, pole-plate, yoke and tor, R. K. Stokes), known as sole 5" and 7" models. A midget .. trans centering ring form a permanent weld agents for Radiokes Precision Pro former designed for highest possible ed unit of rugged durable construc ducts, will also be sharing the factory tion. This welded unit is then used efficiency, the windings and core are representation of the extensive range as a central basis for providing accur of R.C.S. Radio Pty. Ltd. products. ate alignment between the holes in The radio trade is assured that, in the pole.-plat~ and yoke, so that when order to render the best possible ser the pole is assembled, it automatic vice, arrangements have been made to ally drops centrally in the air gap. have available at all times compre Consequently; micrometer tolerances hensive stocks of th,e lines handled. can be achieved so that the efficiency Radio Suppliers Pty. Ltd. are also of the- ma,gRetic circuit is excellent. factory representatives for the manu The high flux density and total energy facturers of a well-known line of in the gap naturally provide high sen power transformers and wirewo.und sitivity, coupled with high-class tran carbon-coated resistors. Of special sient response. interest to the dealer is a new .dual- 1vave 4/5 mantel receiver, incorporat Details Of Suspension• . ing the well-known DAU-1 Unit1 and which can be retailed at a reasonable The corrugated suspension is price and yet show a generous margin Illustrated above is the Am specially designed for the maximum of profit. The set can be pur axial motion so necessary for high plion type SEI 2 electro magnet speaker. chased in one of three ways:-(1) quality reproduction, and ' simultan Completed receiver; (2) wired-up eously it prevents any radial motion hermetically sealed with humidity chassis; (3) coil unit and I.F.'s. which might endanger the voice coil proof compound in a steel casing. All Reverting to radio components, the or cause unpleasant rattles at high transformers are heat-wax treated lines handled will include :-Trolitul power output. Moreover, the cor with a special process for a period of coil units with and without R.F. rugated suspension is attached to a 36 hours before sealing. One side of stage; Trolitul coil units covering all metal support which can be adjusted the primary winding is electrically latest circuits; Trolitul permeability in position simply by loosening two connected to the stack, which is in I.F.'s; Trolitul permeability b'cast 4BA scnhvsi so ~ ' that any service turn insulated from the can, so that ·-. . ' ,-. ~ ; , ' (Continued on page 32) Field Excitation Voice Coil, D.C. Voice Coil Magnet Wght. Wght. of Field Min. Nor. Max. Power Output Model Type ·. :; Weight, lbs. Resistance Impedance, 0%5. Coil, ozs. Wts. Wts. Wts. Undistorted Max.imum Ohms 400 <./s. 5E7 5'! Electro. 2 2.3 3.0 - 7 2 4 6 3 5 5P8 511 Permag. 2 2.3 3.0 8 2 4 7E12 7" 'Electro. 3 2~ 3~ 12 6 8 10 8 12 7P14 7" .Perrilag. 3 2.3 3.0 14 6 10 Page·30 1 The Australasian Radio World, February I, 1940. Long Horn , ,. Publie Address The Amplion P.S. 25' p.a. speaker horn. Speakers Maximium sound coverage from a given output power is ensured by the use of a correctly designed p.a. horn, which provides f ult air loading for the vibrating speaker diaphragm. ·:.i-. By Norman Head, Engineer, Am pl ion (A'sia) Pty. Ltd. THE purpose of speakers, with or action or the ability of the baffle, ling back from the minimu~ flarq di without horns, in public address whether horn or straight board, to mensions, the more efficient it is and work is efficiently and faith minimise the effect of back pressure. the greater the effective amplificat ion fully to translate the electrical or This is the effect of the cancellation of ~: ound due to the loading. audio frequency currents flowing in of the front pressure by the back-of Another.. factor in the efficiency and the amplifier output into sound pres cone rarification. fidelity of the speaker and horn is the sure variations of the free air cover The horn acts like a transformer in acoustic transformer at th ~ throat. ing an audience. matching t!he low pressure of the This is the ratio of the area of the ' The degree of efficiency of the great air space surrounding the audi diaphragm to the throat, a~1d in uni.ts speaker is a measure of the A.F. watt ence to the pressure at the face of in common use is between··3 and 4 to age output of the amplifier in relation the moving element. 1; so that the diaphragm is 3 :or •·4 to the sound propagation. The To be efficient at all frequencies the. times the area of the throat. ·, speaker diaphragm, whether conical horn design must comply with certain For fidelity. characteristics, and in or in any other simple or complex definite characteristics, horns may be thi'l respect also the large cone or shape, is the medium of translation. of various shapes, but to cover the cone-horn unit is inferior to the small Two conditions of action may be con widest frequency variation without diaphragm, the .pliase relationship of sidered; a comparatively large area undue attenuation at either end, the the various frequencies generated cone may by its movement directly logarithmic or exponential horn is the reaching the throat is important. This instigate compression and rareficatiori logical choice. In this horn the is the relation of the distance between of the air, resulting in variation of throat resistance or loading factor is extremes of the diaphragm and t~ air pressure and sound waves. Or a more constant over a wider range and throat orifice, to the wavelength o.f much smaller diaphragm may, has a sharper cut-off. the sound. Its effectc is more notice through an acoustic transformer and To be efficient at the lower fre able at high frequeneies, and shows finally through a horn, produce the quencies the horn must have a cer to a disad\tantage in lar.g-e-area cones. same effect. tain expansion rate along its axis and It is possible to hav1:t 10 watts of The large area cone, even if must have a large flare area; at high frequencies from a large cone·, coupled to a small horn, must effect higher frequencies these constants are which, fuil of phase distortion,, is less large amplitudes with considerable smaller, and a horn correctly loaded intelligjble than 2 watts without ,Phas'e expenditure of power. The small dia for low frequencies will automatically distortion .from a Jong-horn· speaker. phragm coupled to a correctly be correctly loaded for the "highs." E,conomics And Efficiency. · designed horn will have much smaller For instance, a horn with a cut-off Actually cheaper in its own .cost is amplitudes, with correspondingly of 128 c./s. will double in radius every the cone-horn type speaker, for it more economical power input to 12" along the axis and should have simply uses a radio-type dynamic achieve similar acoustic outputs. a mouth radius of about 36," to be speaker coupled to a short horn with The explanation lies in the efficient effective. The final flare dimensions low efficiency. To obtain large power coupling of the vibrating medium to are important and cannot be ignored outputs', large inputs are required. If the air. In the cone unit, the ratio at or varied if efficiency or mouth reflec an efficient long-horn and unit were high frequencies is proportional to the tions are to be avoided, irrespective of used, equivalent output would be ob cone amplitude only, and a smaH the throat. , tained with perhaps one-quarter or horn allows only comparatively small Provided the expansion rate is cor one-fifth of the power input. increae.e ; at lower frequencies this is rectly proportioned and adhered to;. With a long horn unit capable of io further complicated by the baffle the longer the horn, especially tr.ave!- watts i~p,):l,t, the output wou}d be s? The Australasian Radio World, February I! 1940, g·reat that several cone-horns would be required to duplicate it because of their limits of operation. Therefore the efficiency of the long horn unit The NEWEST compensates for its greater initial cost, and actually costs less for the ELECTRICALLY WELDED same acoustic power coverage. And the economics extend further in that an amplifier of much smaller output is required. The Amplion P.S.25 speaker is a 72" exponential horn of careful design coupled to a unit which, properly load ed as it is in this horn, is capable of handling inputs of 10 watts without distress or distortion. And the 10 watts input is comparable with more than three times the power put into cones or cone-horns. That is the efficiency factor. For example, amplification was re quired for community singing con certs held weekly in the Sydney Town Hall, an auditorium of 3,500 people. When Amplion P.S.25 speaker-; re placed the previously used cone-horn types, the power necessary to cover the audience adequately was reduced frum more than 30 watts to less than 10 watL:. Four P.S.25 units were u~ed in the installation, each working at a lower level than 2;5 watts each. Small amplifiers driven from bat teries in police cars with the same speaker unit (P.S.6) have extraordin ary penetration power above street noises, with extremely low power input. The P.S.25 long horn speaker is a sound projector as opposed to the cone-horn sound diffuser. Because a long horn speaker may be mot·e costly in initial expense, it d,1es rot mean that it is actually dearer. By the increase of efficiency, the requirements of fewer units and the decreased cost of amplifier design ancl more economical amplifier power •c•.mrmrnption, an actual saving can be effected, and, further, the fidelity of 4MPLIO-- the speaker is superior. New 5" type shown above has 30% larger cone area than What's New In Radio. any other, sealed insulated core transformer, larger field (Continued from page 30) higher output and frequency response equalled by none! ' Type 5E7 Electro ...... 28/6 coils; Trolitul permeability s'wave Type 5P8 Pemag...... 31 /6 coils; Trolitul iron core I.F.'s; Trolitul New 7" Amplion supersedes all 6}11 and 8 11 speakers. High air core I.F.'s; Trolitul trimmers and fidelity, oversize held, 8" size cone, insulated transformer, padders; 60 m.a. power transformers; 8. l 2 watts output! 2,500, 5,000 and 10,000-ohm wire Type 7E 12 Electro...... 3 1 I - Type 7P14 Permag ...... 40/6 wound volume controls; audio trans formers; R.F. chokes; voltage divi WRITE NOW FOR NEW AMPLION SPEAKER DATA ders; dials; power chokes, etc. (PUBLICATION 88.CI, POST FREE. All products handled by Radio Sup pliers Pty. Ltd. are covered by avail AM,PLION (A'sia) Pty.Ltd. able price lists and leaflets, and buyers would be well advised to cover their 382 Kent, Street, Syd~ey season's requirements now and take advantage of present ruling prices. Th~ A11$trgla~ian Rgdia Warld,- F~bruary 1, 1940. CONDlfCfED BY . ALAN H. GRAHAM Additional New Stations Listed ¥ Night Reception Still Ex Turkey. cels * UHF and Amateur Bands Disappointing ¥ Full List The latest information from Ankara of Month's Loggings. reveals that TAQ is now off the air. The present schedule for TAP is: Week-days, 8.30 to 10 p.m.; 2 to 7.30 Review of Conditions. ope.rating on 9710kc., 30.9m., with the a.m.; Saturdays, 9.30 to 11.30 p.m.; call HJCF. (Universalite). 2 to 7.30 a.m.; Sundays, 8.30 to 10.30 The tendencies in reception con p.m.; 2 to 7.30 a.m. ditions outlined in these columns last Cuba. month have become more pronounced Some confusion has been caused by United States -with early morning reception fair, recent changes of frequency amongst WLWO will soon place in use its and night reception exceptionally Cuban stations. The new station at new lOOkw. transmitter. Using a good-whilst during the day con Santa Clara COHI, operates on 6460 special rhombic beam antenna, pro ditions are very poor indeed. kc., 44.64m., and carries the same pro grammes in Spanish and Portuguese Easily outstanding at present are g;ramme as CMCF, COCH and will be directed to eastern South the 25 and 31-metre bands. In many CMKQ. America. Transmissions will be on years' experience of shortwave recep In addition, COCH is being report 49, 31, 25, 19, 16 and 13 metres. tion 'we have never heard anything ed on a new frequency of 6500kc., (Universalite). to equal the present level of 25-metre 46.15m. Listeners should exercise signals during the night and very care in logging these two stations, as Venezuela. early morning session. they may easily be confused. The Government of Venezuela will New Stations. COCQ is also testing on another shortly place on the air a new 30kw. As in previous months. we are able frequency, 6360kc., 47.17m., and, in transmitter, which will operate with to list a number of new stations. The addition,. is reported from some quar the following calls :-On 6172kc., attention of readers is drawn to the ters as being on 642.5kc., but we have 48.6m., as YVKF; on 9640kc., 31.12m., following:-COHI; COCQ, on a new no confirmation of this. as YYSC; on 11725kc., 25.59m., as frequency; XEWQ; the new Austral ian stations. VLQ and VLQ-2; the South African station at Durban on 25.4!.\m.; KZRB; IISSPJ, on 37.56m.; a new Warsaw station on 25.02m.; and a new German station on the 41- ALL-WAVE ALL-WORLD DX CLUB metre band. PCJ Discontinue Tuesday Afternoon Session. Application for Membership Amongst. shortwave listeners there will be a feeling of deep regret at T·he Secretary, the news that the very popular ses All-Wave All-World DX Club, sion broadcast by PCJ for Australian 117 Reservoir Street, and New Zealand listeners has been Sydney, N.S.W. discontinued. An announcement to Dear Sir, session, probably the most entertain ing on the air, has always attracted this effect was heard at the end of I am very interested in dxing, and em keen to join your Club. December. This Tuesday afternoon The details you require are given belOUI: considerable interest, and the announ cer, Bob Wybrands, was a popular Name...... _.,,_ ...... personality; Address...... Acknow l'edgrnen ts. We wish to acknowledge reports both[Please plainly.)" print ...... from the following:-Messrs. Bantow (Edithvale, Vic.), Neill (Queensland), Chapman and Taylor (N.S.W.), Johns My set is a ...... and Cushen (N.Z.), all "Radio World"' Observers. And also from Mr. 0. G. [Give malce or type ...... aumber of Ta!Tes. Washfold (Camberwell, Vic.) and Mr. and state whether Goucher (South Yarra, Vic.), AW- battery or mains 257DX and A W536DX, respectively, operated.] of the AWA WDXC. I enclo11e hereuiith the Life Membership fee of 3/6 [Postal Notes or Money Order], for uihich I uiill receive, post free, a Club badge and Late.st Station* Changes and a Membership Certificate showing my Official Club Number. Schedules. Colombian Republic. (Signed) ...... - ...... :...... In addition to the new station on [Mote: Beadera who do not want to mutilate their copiem of the "Badio World" by 9740kc., HJFK, another Colombian cutting out this form can write out the delaila required.] transmitter, located in Bogota, is now The Australasian Radio Worl.d__, F.ebru11.~Y J_, J 94.0 •. 1 Page 33 YVOR; and on 15315kc., 19.59m., as 6MIW, 6MUO, 6NPF', 6NHI{, 6PiIF, CENTRAL AMERICA AND WEST YVPX. 6POZ, 6PRB, 6RLF, 6PEV, 60NQ, INDIES. 8GU, 9CFQ, 9DRQ, 9GIQ, 9QI. Costa Rica. * Philippine Is.: KAlME. TIPG, 96l5kc., 31.21m., San Jose: Ultra-High· Frequency Notes. Hawaii: K6- OJI, MV A, PUL, RRM. Widely reported, opening at 10 · p.m. One of best night stations on 31m. 20 Metres. Conditions Poor. (Cushen). South America: LU- lHI, 5AN TILS, 61G5kc., 48.66m., San Jose: During the past two months U.H.F. (Argentine); OA4R (Peru); CE- 3AC, Becoming difficult to log, but still conditions in our locality have been 3AG, 3CG, 3CZ, 3CK, 4AC (Chile); heard weakly at lO' p.m. (Cushen). very poor; a complete absence of HClFG (Ecuador). Cuba. · police band signals; very little on the Africa: EKlAF (Tangier Interna COGF, 11800kc., 25.42m., Matanzas: 10-metre amateur band; and only an tional Zone). Fairly good signal around 7 a.m. on occasional good day on 11 metres. some mornings. Police Bands. Pacific: KB6· !LT, OCL (Guam); K6- MV A, QHU, BNR, MBE, NYD COCM, 9805kc., 30.6m., Habana: We have recently received a veri (Hawaii). Heard weakly from 11 p.m. Varies in fication of our report to the Glendale, frequency, as was heard on 9850kc. California, police department on their The East: KA- lAF, lME, lBH for some time. 33940kc., 8.8m., signals. The Super (Philippines); XU- lB, 8LA, 7HB, COCH, 9437kc., 31.8m., Habana: intendent of Communications, Mr. C. 8AZ, 8RB, 8ZA (China); J. 2NG, Much better signal at present; heard Wasmansdorff (W6LFL) was kind 2XA (Japan); PK- 4KS, 4MM, 5KF from 10 p.m.; also at times in early enough to forward a recent F.C.C. (D.E.I.). morning. list of American police calls and fre COBC, 9350kc., 32.08m., Habana: quencies, which has already greatly * Quite a good signal now, usually assisted us in identifying a number This Month's Loggings. opens just before 10 p.m. (Washfold). of stations heard some time ago. OOCQ, 8850kc., :l3.9m., Habana: The full list of police transmitters Stations not listed in last month's Still heard regularly on this fre heard at the end of last year is: issue are indicated by an asterisk ( *). quency; usually opens at 9.55 p;m,, KQBR, Alameda; WQIE, Newark; but sometimes an hour earlier. See All times are Australian Eastern also 6360kc. (Washfold). and WQKB, Evansville, on 30700kc.; Standard. KQBV. Los Angeles County, on 31900 *COCO, 8700kc., 34.5m., Habaria: New frequency for this station which kc.; WRBH, Cleveland; KQAN, Fort SOUTH AMERICA. Worth; KQBH, Kansas City (Kan was previously on 6010kc. Heard from sas); WQMA, Miami Beach; WQKW. Peru. 10 p.m. Canton; WQNO, Elgin; WQIC. Mc OAX4J, 9340kc., 32.12m., Lima: Be *COHI, 6460kc., 46.44m., Sta. Clara: Keesport; KQAO, Long Beach; coming more difficult to log, but still New station, opening nightly at 9.55 KQBW, St. Joseph: and KQBF, Na heard at times around 7 a.m., and on p.m. (Goucher). tional City, on 33100kc.; KQCI. Glen Sundays between 3 and 4 p.m. *COCQ, 6·360kc., 47.17m., Habana: dale; and WPDS, St. Paul, on 33940kc. OAX4Z, 6077kc., 49.37m., Lima: Once again on a new frequency, COCQ has been heard testing on a 11-Metre Loggings. Still being heard in N.Z., though not audible in our locality, nor reported few occasions. (Johns). W8XNU, 25950kc., ll.56.m., Cincin by any Australian listeners. *COCW, 6330kc., 47.4m., Habana: nati: Most consistent of the stations Heard with good signal at night, now heard on this band, though sel Chile. opening at 9.55 p.m. (Washfold). dom very strong; best around 8 a.m. *CD-1190, 11910kc., 25.19m., Val Panama. W4XA, 26150kc., ll.47m., Nash divia: Still being heard, best reports HP5A, 11700kc., 25.64m., Pariama ville : Very erratic now; heard some being from N.Z. Closes at either 2 City: Fair signal at night; best 10 to times in early morning. or 2.30 p.m. 10.30 p.m. (Chapman). *CB-1170, 11700kc., 25.64m., Santi W9XPD, 25900kc., ll.58m., St. HP5J, 9590kc., 31.28m., Panama ago: Heard fairly well on ·a few oc City: From 10 p.m. Also reported on Louis: Seldom heard now; when log casions, either early morning or be ged, very weak, and hard to copy. 9610kc., 31.22m., and may stay per fore closing at 2 p.m. (Johns). manently on this 'new frequency to W9XJL, 26100kc., ll.49m., Super *CB-970, 9740kc., 30.8m., Valparai avoid QRM. ior: Only heard on rare occasions; so.: Very erratic, but might be heard very weak. before closing just after 3 p.m. Guatemala; CB-960, 9600kc., ·31.25m., Santiago: TGWA, l5170kc., 19.78m., Guate Most consistent of the Chilean sta mala City: Heard at good strength on * tions. Not very good at night, but Sunday afternoons, sometimes for Amateur Bands Review. quite good on Sunday afternoons till whole programme, and sometimes 3.30 p.m. till 5.15 p.m., when change is made to Listeners who concentrate on the Argentine. 9685kc. (Washfold, Goucher, Cushen). amateur bands are now finding it TGWA, 9685kc., 30.96m., Guate *LRX, 9660kc., 31.06m., Buenos mala City: Heard best on Sunday difficult to maintain reasonable logs, Aires: Not heard here lately, but re as conditions have fallen off consider afternoons, though not as good as ported from N.Z., with good signal at formerly (Goucher). ably on both 10 and 20 metres. Very 10.30 p.m. (Johns). few stations are listed this month in TGWB, 6486kc., 46.25m., Guatemala the Calls Heard section. Ecuador. City: Best on Sunday afternoons, HCJB, 124GOkc., 24.08m., Quito: with same programme as TGWA. CALLS HEARD. Heard fafrly well lately from 10.30 TG-2, 6195kc., 48.4m., Guatemala (Reports to hand from Messrs. Chap p.m.; also reported from N.Z. with City: Good signal on Sunday after man, Taylor, .Cushen and Johns). weak signal around 1 p.m. (Chapman, noons in N.Z., but rather weak else Cushen). where. (Cushen, Johns). 10 Metres. Colombian Republic. Dominican Republie. United States: W- 3CBT, 3GRL, HJFK, 9740kc., 30.8m., Pereira: HUN, 12486kc., 24.03m;, Trujillo 3HUM, 4ETV, 4GDR, '5EEL, 5HDK, Opens nightly with good signal at 10 .City: From 9.40 p,m. with weak 51L U, 6ABF, 6AKH, 6ITH, 6LES, p.m. signal. Page 34 The· Australasian Radio World, February f, ' 1940. *HllN, 6243kc., 48.06m., Trujillo Early morning station with good signal in 3-5 p.m. session. (Cushen). City: Heard weakly with same pro signal at 6 a.m. (Chapman). WLWO, 6060kc., 49 .. 5m., Cincinnati: gramme as. 24m. transmitter. WRUW, 11730kc., 25.58m., Boston: Only weakly here at present; but fine Good signal from 7 a.m. (Neill, Wash signal reported in N.Z. at 5 p.m. NORTH AMERICA. fold, Goucher, Chapman). (Cushen). Mexico. WRCA, 9670kc., 31.03m., Bound WDJM (and not WBKM, as given *XEWG, 9680kc., 30.99m., Mexico Brook: Heard till 4 p.m. closing. last month),. 6040kc., 49.6.7m., Miami City: New station heard during after Fair signal; very strong in N.Z. Beach: Reported from N.Z. ; excellent noons till just before 4 p.m. with (Johns). , signals on Sundays from 3.30-4 p.m. English announcement. (Goucher). WCAB, 9590kc., 31.28m., Philadel (Johns). XEWW, 9503kc.,. 31.57m., Mexico phia: Another afternoon station, till WRUL, 6040kc., 49.67m., Boston: City: Consistent afternoon around 3 5 p.m. (Washfold, Goucher). Occasionally heard with special t~st p.m.; also audible at times after mid WBOS, 9570kc., ·31.35m., Boston: transmission. night. (Cushen, Goucher). Another afternoon American, closing AFRICA. *XEXA, 6133kc., 48.9m., Mexico at 5 p.m. City: Reported from N.Z., with good WGEA, 9550kc., 31.41m., Schenec C<~nary Is. signal from 2-3 p.m. in English hour. tady: Heard weakly some mornings EAJ-43, 10360kc., 28.96m., Tene (Johns). around 9 a.m. (Bantow). riffe: Heard at times in early a.m., Canada. WGE:O, 953.0kc., 31.4Sm., Schenec just before 6 a.m. (Neill). tady: Quite strong signal· from 6 · a.m. *CJRX, 11720kc., 25.6m., Winnipeg: till nearly 9 a.m. (Chapman, Kenya. Difficult to log, but best time is on Goucher). VQ7LO, 6083kc., 49.31m., Nairobi: Sunday afternoons when station is on Still heard in early mornings, 5 a.m., till 7 p.m. KGEI, 9530kc., 31.48m.. Schenec tady: Heard in afternoons from 4-6 though hardly as good as previously. United States. p.m.; also from 10 p.m., though inter (Chapman). WCBX, 21570kc., 13.9lm., New fered with by JZI in some locations Bechu anal'and. York City: Opens at 11 p.m., but at this time. (Chapman, Goucher). ZNB, 5900kc., 50.85m., Mafeking: heard best after midnight. *KEI, 9490kc., 31.61m., Bolinas: Still heard in the' early mornings, *-WCBX, .. 178·30kc., 16.83m., New Another relay station for Hawaiian closing 5.30 a.m. programmes. York City: Reported at good strength South Africa. in early a.m. from Queensland. *KEE (?),approx. 37m.: American (Neill). relay station reported from N.Z. by *Durban, 11770kc., 25.49m.: New WNBI, 17780kc., 16.87m., Bound Mr. Johns. Hearcj. at good strength station, call unknown, heard around Brook: Good signal in early mornings; on Sunday afternoons closing at 3.45 2 a.m. relaying ZRO on 9752kc. very weak now in forenoon. (Neill, p.m. ZRO, 9752kc., 30.77m., Durban: Chapman, Goucher). WCBX, 6120kc., 49m., New York Easily logged just before closing at WGEA, 15330kc., 19.-56m., .Schenec City: Reported from N.Z. with good 2.15 a~m . tady: Good early morning signal. (Neill, Chapman, Goucher, Johns). KGEI, 15330kc., 19.56m., San Fran cisco: Weaker now, but still heard around 2 p.m. (Neill, Johns, Wash Dav·e Your ~~RADIO WORLD" fold). WCAB, 15270kc., 19.65m., Philadel Posted To You Direct phia: Quite good strength in early morning. Readers who want to take the "Radio World" on a subscription WCBX, 15270kc., 19.6.5m., New York basis and have their copies posted to them direct each month are City: Good signal in early mornings, invited to complete the coupon below (annual sub., 10/ 6). New closing 6.30 a.m. (Chapman). readers are advised that all back numbers in Volumes 1, 2 and 3 WRUL, 15250kc., 19.67m., Boston: Sometimes used in place of .WRUW, are still available, price 9d., p.ost free, for all copies up to and in 15130kc. (Chapman). cluding the December, 1938, issue ,and 1/ -, post free, for subsequent WPIT, l5210kc., 19.72m., Pitts numbers. burgh: Quite good signal from mid nigl)t till 5 a.m. (Neill, Cushen). Enclosed please .find remittance for 10/ 6 in payment for an WRUW, 15130kc., 19.83m., Boston: Good, clear signal, IClosing 8 a.m. annual subscription to the "Australasian Radio World," com- (Chapman, Goucher). mencing with the...... issue. KKZ, 13690kc., 21.91m., Bolinas: Special relays to Hawaii. Name ...... KKQ, 1l950kc., 25.lm., Bolinas: Also used for special relays, around 3 p.m. Street and No...... WPIT, 11870kc., 25.26m., Pitts burgh: Nice signal in early morning, City ...... State ...... best from 7 a.m. (Chapman,, Goucher). WCBX,.. 11830kc., 25.36m., New Country ...... York City: From 7 a.m., with fine, steady signal; one of best morning THE AUSTRALASIAN RADIO WORLD Note:-N.Z. Subscribers stations. (Goucher, Chapman). 117 . Reservoir Street, Sydney. should remit by -Money WRUL, 1179Qkc., 25.45m., Boston: Order. The Australasian Radio . World, February 1, 1940. Page 35 ZRL, 9606kc., '31.23m .. Klipheuval: * JLT-2, 9645kc., 31.lm., Tokyo: *A new station on approx. i1850kc., Heard fairly well at same time as Good signals from this station in 25.32m .. heard around 9 p.m. nighlty, ZRO. early mornings till 6.30 a.m. (Neill). is thought to be located in Indo-China, JZI, 9535kc., 31.47m., Tokyo: From but few details are available at time AUSTRALIA. 10 p.m. nightly; badly interferes of writing. with KGEI in some localities. (Chap China. VLR-3, 11880kc., 25.25m., Lynd man, Goucher, Johns). hurst: Used from 6.30 a.m. till 5.15 p.m. (Washfold, Chapman, Johns). *JLG, 7285kc., 41.lm.. Tokyo: XGOX, 15190kc., 19.75m., location Seems to be used irregularly; some uncertain: Strong signal at night *VLQ-2, 11870kc., 25.26m., Sydney: times at good strength early morning around 7 p.m. Often used in sp~cial New Australian national shortwave or at night. transmissions to U.S.A., Hawaii, etc. station. Transmits to Europe 5.30- (Washfold, Chapman, Goucher). 6.30 p.m. (Washfold, Cushen, Johns). JVW, 7257kc., 41.34m., Tokyo: Used with .JZI in 5-7 a.m. session XGOY. 11900kc., 25.21m., location VL W-3, l 1830kc., 25.36m., P~rth: (Chapman, Johns). unknown: Just fair in the morning, Heard testing; also used for natiqnal but very strong at night. (Bantow, shortwave service to Africa, 3.30-4.30 • JLT, 6190kc., 48.4 7m., Tokyo: Chapman, Goucher, Johns). p.m. (Washfold, Bantow, Chapman). Heard here occasionally; and often re ported from N.Z. XMHA, 11855kc., 25.3m., Shanghai: *VLQ, 9615kc., 31.2m., Sydney: Remains a fairly good signal at night. Used for transmissions to Europe and JZI, 9535kc., 31.47m., Tokyo: From (Washfold, Chapman, Goucher). America. (Washfold, Cushen). rn p.m. nightly; badly !nterferes with KGEI in some lo~alities. (Chapman, *XGOK, 11650kc., 25.7-5m., Canton: VLR, 9580kc., 31.32m., Lyndhurst: Goucher, Johns). Note change of frequency from 11820 Used at night. kc. Fairly strong. News at 11.15 ''JLG, 7285kc., 41.lm., Tokyo: p.m. *VLW-2, 956.0kc., 31.38m., Perth: Seems to be used irregularly; some Testing in early a.m. (Washfo!d). times at good strength early morn *XGAP, 9560kc., 31.38m., Peking: VLW, 6130kc., 48.94m., Perth: ing· or at night. Renorted from N .Z., and sometimes Testing from 9 p.m. JVW, 7257kc., 41.34m., Tokyo: Used audible here around 1 a.m. with JZI in 5-7 a.m. ~ession. (Chap *XTC. 7000kc., 42.Sm., Kweiyang: One of strong regulars at night. THE EAST. man, J'ohns). *JLT, 6190kc., 48.47m., Tokyo: (Washfold). Phil'ippine Is. Heard here occasionally, and often XOJD, 6880kc., 43.6m., Hankow: reported from N.Z; Never very loud, but usually audible *KZRB, 11840kc., 25.34m., Manila: after 9 p.m. New station heard testing one night Hong Rong. after 8 p.m. Not onl regular schedule Dutclh East Indies. zBw-3, 9525kc., 31.49m., Hong KZRH, 9660kc., '31.06m., Manila; Kong: Good signal nightly. (Wash- YDB, 15310kc., 19.6m., Bandoeng: This new frequency for the "Voice of fold, Bantow). Heard during afternoon, around 4 the Philippines" is reported from all p.m., at fair strength. (Washfold). parts of Australasia at good strength. India. YDC, 15150kc., 19.Sm., Bandoeng: (Washfold, Bantow, Goucher, Cushen, VUD-3, 15290kc., 19.62m:, Delhi: Good signal at night; also at times Johns). Heard in early afternoons till 2 p.m. frorn 9 a.m. (Goucher, Washfold RZRM, 9570kc., 31.3-5m., Manila: and also 4.30-6.30 p.m. (Johns, Banto·w). Good strong signal every night. Goucher). PLP, llOOOkc., 27.27m., Bandoeng: (Johns, Neill, Washfold, Bantow, VUD-2, 9590kc., 31.28m., Delhi: Relays YDC; good signals at night. Chapman, Goucher). Fine signals from 10.30 p.m., opening (Washfold, Chapman, Goucher). KZIB, !J500kc., 31.58m., Manila: An with news in English. (Washfold, PMN, 10260kc., 29.24m., Bandoeng: other good station at night. (Neill, Bantow, Goucher, Johns). Also a NIROM relay station; fairly Washfold, Bantow, Goucher). VUD-18, 4960kc., 60.48m., Delhi: strong at night. (Washfold, Chap KZEG/KZRF, 6140kc., 48.86m., Fairly strong from 10.30 p.m. man, Goucher). Manila: Very strong signal every VUM-2, 4920kc., 60.98m., Madras: YDB, 9-550kc., 31.41m., Bandoeng: night. Uses both calls, though RZRF. Weak. (Chapman). Nice steady signal from this station (Washfold, Bantow, Chapman). around midnight. (Goucher). KZRH, 6100kc., 49.lSm., Manila: . VUB-2, 4880kc., 61.48m., Bombay: Fair. (Chapman). YDX. 7220kc.. 41.55m., Medan: Fairly good signal. (Neill). Mainly native programmes; fair l{ZIB, 6040kc., 49.67m., Manila: VUC-2. 4840kc., 61.98m., Calcutta: Fair. (Ghapman). signal. Good si~nal nightly. (Washfold). PM.H, 6720kc., 44.64m., Bandoeng: Japan. Malaya. Native programmes at good strength; very reliable. (Washfold, Goucher). JZK, . lb160kc., 19.79m., Tokyo: ZHP. 9690kc., 30.96m.. Singapore: Fairly strong in early mornings Still a good signal, but QRM is some YDD, 6045~c., 49.63m., Bandoeng: around 7 a.m.; also heard 11 a.m. times troublesome. (Washfold, Chap Not very good, but audible on most (Chapman, Goucher). man, Goucher, Johns). 'lights. (Washfold, Chapman). JVH, 14600kc., 20.55m., Tokyo: Re ZHJ, 6080kc., 49.3in., Penang: Not *PMY, 5145kc., 58.31m., Bandoeng: ported from N.Z. so good now, but still to be heard. Fair signal above high noise level. (Washfold). JZJ, 11800kc., 25.42m., Tokyo: Manchukuo. Heard in early mornings, and from French Indo-China. *JDY, 9920kc., 30.24m., Daire:n: 10 p.m. (Neill, Chapman, Goucher). Again being heard from 10 to 11 p.m. Radio Saigon, 11780kc.. 25.47m., (Washfold). JVW-3. 11720kc.; 25.6m., Tokyo: Saigon: Exceptionally strong signal Good signaL nightly. (Washfold, Ban nightly. English session is now MTCY, 11775kc., 25.48m., Hsinking: tow, Goucher, Cushen). from 8.45 to 9.15 p.m. (Neill, Wash From 7 a.m. with fair signal. (Chap JLG-3, 11705kc., 25.63m., Tokyo: fold, Ban tow, Chapman, Johns, man, Goucher, Cushen). Also heard ~t night. Goucher). MTCY, 6125kc., 48.98m., Hsinking: Page 36 The Australasian Radio World, February I, f940; From 11.30 p.m.; no 8ngiish used. strength; aiso around 10 p.m. at Ai•bania. (Neill). week-ends. ( Go~cher). ZAA, 6085kc., 49.3m., Tirana: At 'I'hailantl. Lithuania. fair strength from 3.20-7 a.m. HS6PJ, 19020kc., 15.77m., Bangkok: L YR, 9285kc., 32.34m., Kaunas : Hungary. Used on Monday nights in December, Reoorted from N .z. between 4.30 and *HAS-3 15370kc., 19.52111., Buda but replaced, temporarily at least, by 5.15 p.m. (Johns). pest: On!~ on t he air from midnight 7960kc., transmitter. Still heard with fair signal till 6 a.m. on Sunday;;, with English announce HSSPJ, 9510kc., 31.55m., Bangkok: Belgium. ments. (Goucher). Replaced recently by 7960kc. trans mit_ter. ORK, 10330kc., 29.04m., Ruysselede: Vatican City. (Chapman). *HSSPJ, 7960kc., 37.56m., Bangkok: Spain, HYJ, 15120kc., 19.84m.: Very New station, replacing transmitters on EAQ, !)860kc., ·30.43m., Madrid: strong on Tuesday nights from 11.30 15 and 31m. Heard at good strength. Does not seem to have regular p.m. (Goucher). (Goucher, Cushen, Neill). schedule; heard as early as 3.10 a.m. *HVJ, G190kc., 48.47111. : Good signal Taiwan. anq .also irregularly at 7 a.m. (Neill). on Sunday mornings, opening 5.30 JIE-2, 9695kc., 30.95m., Tyureki: Switzerland. a.m. Weak signal after midnight. JFO, 9635kc., 31.l3m., Taihoku: Norway. Seldom very loud; reported from LKV, 15170kc., 19.78m., Oslo: Still Queensland at 1.30 a.m. (Neill). DX Club Requirements. heard in the very early morning, 1-2 JIE, 7295kc., 41.13m., Tyureki: a .m.; reported at 4.20 a.m. with Eng All-Wave All-Wond DX Club lish ·session from Queensland. (Neill). Transmits at same time as JIE-2; fair members are advised that the signal at midnight. (Cushen). following DX requirements arc *LKQ, 11735kc., 25.57m., Oslo: Best on Sunday nights around 8.45 p.m. Burma. obtainable from Club headquar ters, 117 Reservoir St., Sydney. with church service. (Johns). XYZ, 6007kc., 49.94m., Rangoon: Just fair after midnight. (Chapman, REPORT FORMS. - Save Finland. Neill). time and make sure of supply *OIH, 17800kc., 16.85m., Lahti: ing all the information requir Heard weakly some nights till Daven ed by using these official forms, EUROPE• . try opens at 8.40 p.m. which identify you with an es Portugal. tablished DX organisation. Bohemia. "CSW-4, 15215kc., 19.71m., Lisbon: Price ..• 1/ 6 for 50, post free. *OLR5A, 15230kc., 19.7m., Prague: Fine signal from 2-3 a.m. NOTEPAPER.-Headed Club Heard weakly on several occasions in CSW-6, 11040kc., 27.17m., Lisbon: notepaper for members' corres 7 p.m.-midnight session. Good steady signal from 3.45-6.30 pondence is also available. a.m. (Chapman). Italy. Price, 1/6 for 50 sheets, post 2R0-15, 11760kc., 25.51m., Rome: CSW-7, 9740kc., 30.Sm., Lisbon: free. From 7 a.m. with steady and regular Latest EIAR transmitter on the air. signal. (Goucher). DX CLUB STICKERS.-En Heard as early as 9 p.m., but much Sweden. larged two-colour replicas of the louder at 1 a.m. (Chapman). Club badge, in the form of gum *2R0-14, 15230kc., 19.'im., Rome: SRT, 15155kc., 19.8111., .Motala: med stickers, designed for at Heard best on Sunday nights, after Heard irregularly in early morning or taching to envelopes, QSL at night {with 2R0-15). (Chapma11). 7 p.m'. . (opening at 6 p.m.). (Johns). cards, etc. Price, 5 dozen for SEP, 11705kc., 25.63m., Motala: 1/6, post free. Also logged: 2R0-3, 9635kc., Heard till 7.15 a.m. with fair signal. 31.13m.; 2IW-4, 11810kc., 25.4m.; (Neill). DX CLUB LOG SHEETS. 2R0-6, 15300kc., 19.61m.; 2R0-8, Designed by the Shortwave 17820kc., 16.84m.; 2R0-9, 9667kc., Holland. Editor, these headed and ruled 31.03m.; and IRF, 9830kc., 30.52m. PHI-2, 17770kc., 16.SSm., Huizen: log sheets are indispensable to (Washfold, Neill, Bantow, Ghapman, Seldom very loud, but heard most dxers who wish to keep a simp John>:, Cushen). nights; best on Sundays from 9.40 ly-prepared and accurate list of p.m. (Neill, Bantow, Goucher). loggings. Price, 3 dozen for France. 1/6, post free. PCJ-2, 15220kc., 19.71m., Huizen: *TPB-11, 7280kc., 41.21m., Paris: Tuesday afternoon session now off the Heard fairly well lately around 6 a.m., air, but can still be heard quite well closing 7.15 a.m. Also reported at 6 around 11 p.m. (Neill, Washfold, p.m. (Johns, Cushen). Goucher, Cushen). HBO, 11402kc., 26.32m., Geneva: Heard on Sunday afternoons around Also logged: TPB-3; 17765kc., PCJ, 9590kc., 31.28m., Huizen: Good 6.30 or 7 p.m. (Chapman). 16.88m. (note change of frequency); signal in early mornings, Mondays TPA-2, 15245kc., 19.6.Sm.; TPB-6, and Wednesdays. (.Chapml/-n). *HBJ, . 14535kc., 20.64m., Geneva: 15t30kc., l9.83m.; TPB-11, 1188~l;:c., Sam" programme as HBO. Poland. 2.5.24m.; TPA ·4, 11715kc., 25.6lm.; Yugo-Siavia. and new station on 9680kc., 30.99m. *Warsaw, 11990kc., 25.02m.: New (Washfold, Neill, Chapman, Johns, German station heard from 7 p.m. till YUC, 9.505kc., 31.56m., Belgrade: Cushen). · midnight. German seems only lan Good early morning station. (Neill, guage used. Chapman). U.S.S.R. Turkey. *YUA, 6100kc., 49.18m., Belgrade: Stations lo~ged: RV-96, 15400kc., Not heard in our locality recently, but 19.47m.; RV-96, 15180kc., 19.76m.; TAP, 9465kc., 31.7m., Ankara: An reported from Queensland in early RKI, 15083kc., 19.89m.; RNE, 1200 other regular morning station at good morning. (Neill). kc., 25m.; RAN, 9600kc., 31.25m.; The Australasian R.adio World, February 1, 1940. Page 37 RV-96, 9526kc., 3L51m.; and RV-15, 4273kc., 70.21m. (Washfold). England. Stations logged: GSA, 6050kc., 49.59m.; GSB, 9510kc., 31.55m.; GSC, 9580kc., 31.32m.; GSiD, 11750kc., 25.53 m.; GSE, 11860kc., 25.29m.; GSF, 15140kc., 19.82m.; GSG, 17790kc., 16.86m.; GSH, 21470kc., 13.97m.; GSI, 15260kc., 19.66m.; GSJ, 21530kc., 13.93m.; GSO, 15180kc., 19.76m.; GSP, 15310kc., 19.6m.; GST, 21550kc., 13.92 m.; GSV, 17810kc., 16.85m.; GSW, 7230kc., 41.49m.; and GRX, 9690kc., ·30.96m. (Washfold, Bantow, Goucher, Chapman, Neill, Johns, Cushen). We Guarantee Results ! Germany. The five-band "World-Cruiser Communications. Eight" is easily the finest *A new German station operating receiver of its type yet described in any Australian maga:1dne. We will on approx. 41.6m. is reported from assemble and air-test your model for you ... AND WILL GUARANTEE N.Z. by Mr. Johns. Heard at 5.30 TO DUPLICATE THE MAGNIFICENT RESULTS- GIVEN BY THE''RAD10 p.m. with strong signals. WORLD" LABORATORY MODEL. W R I T E N 0 W F 0 R 0 U R Q U 0 T A T I 0 N. Stop-Press Notes. Want a Receiver Built, A report just received from Ob Lined up .. or Serviced ? server W. H. Pepin, of Maylands, West Australia, lists the following If so, we are fully equipped to handle the job for you. For years we have stations:- specialised in building to private orders all types of receivers (A.C., D.C., A.C./ D.C., vibrator, battery, dual-wove, all-wave or short-wave), ampli HS7PJ, 37.65m., is now the regular fiers of all types (P.A. sys.tems a speciality), auto and portable radios. channel for the Bangkok station. It Sets built to individual requirements, or we will design to suit any conditions. is heard nightly from 11 p.m.- 1 a.m., except on Mondays, when HS6PJ, on 15.77m., is used. 11 Little Wanderer11 Portable Radio Other Eastern stations log~ed : City, beach or bush ... anywhere, at any time, a flick of a switch will VUB-2, on 31 metres, and the four bring you a weo.lth of radio entertainment from this sensational new 1.4-volt Indian transmitters on 60-61 metres; portable radio. XGOX and XGOY; __ JZK and JZJ; MAIN FEATURES INCLUDE: YDC, YDB, on 19.6 and 31m.; YDX; PMH, PLP and PMN; KZRM, KZIB e Powerful five-valve s.uperhet circuit (using 1.4-volt valves) specially and KZRH, all on 31 metres. Lower developed to give maximum in performance with minimum running frequency stations also include costs. YDL-2, on 62 metres; YDA, on 98 8 Six-inch Rola P.M. speaker with high-sensitivity magnet ensures ample metres; and RV-15. volume with superb tone. Europeans heard include the major e Litz-wound iron-cored coils and i.f. transformers give exceptionally ity of the Daventry and Berlin trans• high sensitivity. mitters now on the air; also Paris, on e New improved o.v.c. s.ystem, station-calibrated dial, non-directional a number of frequencies, including the lid aerial, with provision for attaching outside aerial. 41.2 metre transmitter; and RNE, RAN and RV-'59 on 50 metres. The new Australian stations are PRECISION RADIO listed:-VLW, VLW-2, VLW-3, VLQ and VLQ-2. D. T. MARTIN, M. Inst. R.E. (Aust.) Amateur loggings on 20 metres 20 CARRINGTON ST. NORTH, are:-W- 3, 4, 5, 6, 8, 9; XU STRATHFIELD, SYDN,EY. SAM, lB, lA; J2NF; K6- CMC, BNR, 'Phone UM 7858 MVA; PK, lMF, lOG; KA- lAF, lLB, lFM, lAG, lBH, IJM, lAR, lMN, lCW, lSM, lOZ, 4LH. Page 38 The Australasian Ra!lio World, February 1, 1940. Modulated OsciHators. The reverse process can also The output on all bands is less (Continued from page 10) take place when the oscillator is than that given by the a.c. version, operated at a frequency lower than but is useful up to approximately 15 ceiver is fitted with a sensitive tuning the signal input frequency. m.c.'s (20 m.) above which the out indicator this operation is greatly put falls off rapidly. simplified. Multi vibrators. Application Of Multivibrator. Short Wave Bands. The multivibrator is a form of os cillator which, in addition to the As will readily be appreciated, such On the short wave bands, the short usual fundamental frequency, pro an imtrument cannot be calibrated in comings of service oscillators in regard duces also a large number of equally terms of frequency, and consequently to output impedance and attenuation spacect harmonics. For this reason cannot be used for aligning- i.f. trans are usually severe, and satisfactory and also for the fact that it is simple formers or calibrating dials in terms alignment in the normal manner may to design and construct and hence of frequency. It is, however, be very difficult. Under such con rel::.tively inexpensiYe, it is extremely extremely useful for aligning the ditions, it is advisable to align the useful in service work. The usual tuned circuits, especially on the short tuning circuits with the normal aerial form of multivibrator oscillator con wave bands. connected, and the output lead of the sists of a two-stage resistance Having once set the oscillator trim oscillator twisted around it. As be coupled amplifier, in which the output mer to a satisfactory position (at fore, no higher input voltage should voltage of the second valve is fed the high-frequency end of the band), be used than is necessary to give a back through a resistive capacitive the output lead of the multivibrator satisfactory reading on the output network to t.he grid of the first valve. may be connected to, or brought near meter. The fundamental frequency and hence the aerial terminal of the receiver, In the majority of receivers the the spacing of the harmonics is de and the signal frequency circuits then padding condenser is of fixed capaci termined by the time constant of the aligned for maximum output in the tance and adjustment ~annot readily coupling condensers and resistors. A speaker. be made for tracking. Should "dead multivibrator may be designed having The receiver may then be tuned to spots" occur in the band, it may be a fundamental frequency of approxi the low-frequency end of the band, necessary to effect a compromise in mately 500c/s, and producing har and the padder adjusted for maximum the setting of the trimmers so that monics spaced every 500 c/s to ap output. It is unnecessary to rock the more even sensitivity will be obtain proximately 20 m.c.'s ( 15 m.). ed across the band. Such a measure gang condenser, since with the multi should not, however, be necessary in The high-frequency harmonics may vibrator in operation, there is always a well-designed receiver. be picked up by a normal radio re a signal present, no matter to what If the padding condenser is of fixed ceiver, but are too close to be in frequency the receiver happens to be capacitance, the only means of set dividually separated, and constitute a tuned. After adjusting the padder, ting the dial calibration is by means continuous signal across the whole of the aerial and r.f. trimmers should of the oscillator trimmer at the high each wave-band. After rectification, be re-checked at the high frequency frequency end of each band. Care the audio-frequency components con end of the band. must be exercised to discriminate be sist of the fundamental .500 cycle Another important advantage in tween the signal and the "image" tons together with its audible har the use of a multivibrator is that it which may be very prominent in monics. is possible to check, quickly and easily, small receivers. (The occurrence of Fig. 17 shows the circuit of a prac each wave-band in a receiver for "images" or "second spots" was dis tical multivibrator oscillator using the dead spots or variations in sensitiv cussed at greater length in Lecture 1). twin-triode type 6FSG. Connected as ity by the simple expedient of listen Another effect which must be ap shown, the circuit produces a wave ing to the output from the multi preciated is the 'crossing-over" effect. form similar to that shown in Fig. vibrator, as the receiver is tuned In the majority of receivers the os 18. The amplitude of the harmonics across each band. The output from cillator is tuned to a frequency steadily decreases with increase of rising frequency, but does not vary higher than the signal frequency, the frequency, although from an experi the multivibrator falls gradually with oscillator coil being slightly smaller mental oscillator sufficient output rising frequency, but does not vary than the aerial and r.f. coils. If, voltage could still be obtained at 12.5 greatly from point to point. however, 'the range of the trimming metres to align a sensitive receiver. condensers is great, it is sometimes "1940 Companionette Three,." possible at the high-frequency end of The output voltage may be varied the band to tune the local oscillator to by means of the 0.05 megohm poten (Conrtinued from page 8) tiometer in the output circuit, but a frequency lower than that of the Short Aerial Is Be~it In City complete attenuation can only be ac signal frequency circuits. Under Lo·cations. these conditions, as the receiver is complished if the whole assembly is tuned across the band, the resonant effectively shielded. The same general The "Companionette" is highly sen frequency of the aerial and r.f. cir precautions are necessary as outlined sitive, so that in metropolitan areas cuits decreases more rapidly than that in connection with modulated osci1- only a few feet of aerial wire are of the oscillator circuit and a point lators. needed to give more than ample vol of cross-over occurs beyond which Fig. 19 shows an alternative design ume from all locals-in fact, in such the oscillator frequency is above the using type 1G6G, operating entirely locations a short aerial is definitely sig;ial frequency. At the point of from dry batteries. The battery drain advisable. In country locations, how cross-over, i.e., where the two fre is very low, being 100 m.a. for the ever, with a good outside aerial and quencies are equal, instability is likely filament and approximately 3 m.a. an effective earth, excellent inter to be experienced. for the plate supply. state reception can be expected. The Australasian Radio World, February 1, 1940, Pa9e 39 New A.C.-Battery Portable. played at full volume at any time Radiotron Designer's Handbook. Now during the day, while at night thirty comes the third edition, and of this (Continued from page 3) or forty local and inter-state loggings it is no exaggeration to say that it is were common. Aroud 10.15 p.m. any a veritable paradise of information particularly appreciated by those who night the New Zealand Y A's, together are hard of hearing, or by hospital for the radio engineer. It is much with several Japanese stations, were larger than the first two editions, con patients, etc. logged. The valve line-up of the Model 169 taining a total of 352 pages, with is as follows: 1N5G r.f. amplifier, Por the tests mentioned above, the more than 300 diagrams and charts. set was carried around to differe·1t 1A7G mixer, 1N5G i.f. amplifier, J.H5G It is evident at first glance that locations in a Flying Standard road diode second detector and triode the editor, Mr. F. Langford Smith, driver, 1Q5G beam output tetrode and ster. Car-owners wHI be interested to know that the Model 169 could be B.Sc., B.E. M.I.R.E. (U.S.A. and Aus a 5Y3G rectifier in the a.c. power unit. trr.lia), A.M.I.E.E., A.M.I.E. (Aust.), The circuit used incorporates rnv played at full volume during these trips with negligible noise from the set out with the primary object of eral ingenious features, apart from making this a compi'. ation of material standard refinements such as full motor, which incidentally is not fi : automatic volume control and auto ted with suppressors of any kind. of the utmost possible value that matic bias. Th3 intermediate fre Thus this new Breville release, could be included in the space avail quency chosen is 252 k.c., giving ex which is both light and compact, able. tremely high gain and excellent selec makes the ideal all-purpose receiver. The chapters deal with A.F. voltage tivity, with a minimum of undesirable In the home, on picnics, at week amplifiers of all types, A.F. power reaction with the built-in loop aeral. enders, in; the car ... it can be play amplifiers, power output and speaker Sensitivity of the receiver operating on ed anywhere, at any time. relationship, biasing, by-passing and the loop is better than .5 microvolt Complete Data Free On Request. decoupling, fidelity and d:stortion, per metre, which explains its remark negative feedback, Miller effect, aud:o able distance-getting powers. Further details of both Breville "Duo" models, and of other standard amplifier design, tone compensation Fool-proof A.C. Operation. type battery portables made by the and tone control, volume expansion company, are available free on re and compression, recording, pick-ups, On the a.c. side the Model 169 has quest from Breville Radio Pty. Ltd., microphones and amplifiers, A.F. mix been skilfuliy engineered to g·ive reli 67-73 Missenden Road, Camperdow,1, ing systems, decibels, R.F. amplifiers, able, hum-free operation, the circuit N.S.W. frequency conversion, tuned circuits arrangement being designed to safe and inductance calculations, I.F. am guard both receiver and valves against plifiers, detection, A.V.C, A.F.C., re damage under all conditions. Actu Book Reviews. ally the receiver can be switched to flex amplifiers, .rectification, receiver battery operation without damage (Continued from page 4) components, formulae, logarithms, while it is still connected to the mains. measuring instruments and much The chapter dealing with modula other data. The power transformer, with a tap tion equipment is one providing a ped primary to match 220, 240 or 260- Contrary to expectation, this Hand volt mains, operates in conjunction wealth of material for the public ad book, which contains a great deal dress amplifier enthusiast, for any of with a 05Y3G rectifier to deliver an more informative data for the pro unsmoothed output of approximate1y the modulators described can be ap fessional radio engineer than any 110 m.a. at 110 volts. This is used plied for that purpose. The latter foreign .Manual we have seen, is no . for both "A" and "B' supplies, in the section of this Handbook is devoted to expepsive purchase, the price being following way:- the latest applications of u.h.f. equip 3/- (postage 4d.). When the receiver is switched over ment, covering oscillators, transmit It is now available from McGill's to a.c. operation, a 4 x 2 position ters, receivers and aerial equipment Newsagency, Melqourne, and other switch throws' the valve filaments into for frequencies from 56 m.c. to 112 a series-parallel arrangement draw bookstalls throughout the Common m.c. and higher. wealth, or from Amalgamated Wire ing .1 ampere at 4.2 volts. A 1000- The laboratory man will find much ohm voltage dropping resistor is con less Valve Company Pty. Ltd., at to occupy him in the chapter dealing 47 York Street, Sydney. · nected in series with this network, the with instruments for checking fre whole being across the unsmoothed rectifier output. Thus, of the 110 quency and. modulation, audio and r.f. mills. at 110 volts available, 100 miils. signal generators, D.C., A.G. and r .f. are used for "A" supply, leaving 10 voltmeters and oscilloscopes. 42-Foot Aerial Pole. mills. at 110 volts (unsmoothed) for Apart from the primary interest of the "B" and automatic bias suppli»>. experimental radio, the 1940 edition The greater part of my spare time Wirewound resistor:; a11u 111gh capac of The Radio Amateur's Handbook lately has been spent on my 'new i t)' electrolytic condensers provide contains. such a wealth of practical 42ft. pole. I am using 22 feet of 4'" very complet~ smoothing of both sup and theoretical information that it is x 3" of oregon and 22 feet of 2" x 3" plies, reprod!J,ction on a.c. being en of great value to the professional of same wood, with two cross beams tirely hum-free. radio engineer, and should be handy at top of 4" x 3." The base com in every radio laboratory. prises two: pieces of 5" x 2" hardwood An Excellent Performer. (Our copy from McGill's Newsagency, 183-5 Elizabeth St., Melbourne. price 10/8 posted I. sunk into the ironstone for 12," and During a period of a fortnight the a 4' square cement block built up receiver was 0 tested under a wide var around it to 6" above the· level of the iety · of conditions, with consistently * lawn. The eight main guy wires are excellent results. Sensitivity is ex of No. 12 steel wire, insulators being ceptionally high, so much so that in Radiotron Designer's Handbook. none of the fr1any test locations visit placed every 6ft. The four wires ed was there the slightest need for About six years ago Amalgamated from top of the cross-bean -inds to an external aerial and earth. Wireless Valve Company furni~h e d a base are of 14-gauge wire. They are In all locations in and arou-1 Syd valuable aid to the radio engineer in plans for my new pole.-R. Suther ney at least fifteen stations could be publishing the first edition of the land (AW458DX), Balgowlah, N.S.W. Printed by the Bridge Pr.intery, 117 Reservoir St., Sydney, N.S.W., for the proprietors of the "Austrolasian Radio World," 117 Reservoir St., Sydney. Page 40 The Australasian Radio World, February 1, 1940. ,. ·~ r11 ~ - ~ - ....~ •...;;;.,.,. "QUEEN MARY" T;:::::' USING BRIMAR VALVES BREAKS ALL RECORDS INSIST ON BRIMAR VALVES FOR MARINE RADIO TRAFFIC! FOR YOUR "WORLD CRUISER" COMMUNICATIONS EIGHT. The safety of the £6,000,000 liner "Queen Mary" and its thousands of passengers depends on the reliability and efficiency of BRIMAR valves. Brimar Valves are also specified for the "World Cruiser Communications Eight" described in this month's issue of "Radio World." Ensure peak performance and unequalled dependability by insisting on BRIMAR. 1940 COMPANIONETTE 3 MIDGET AMPLIFIER The following Brimar valves are specified For the "Midget Amplifier" described for the "1940 Companionette Three" this month, insist an Brimar Valves as described in this issue :-Brimar 6F7, specified. Types required comprise combined r.f. pentode and triode detec Brimar 57 first audio stage; Brimar type tor; Brimar 6AG6G, high-gain output 58 second audio stage; Brimar type 2A5 pentode, and Brimar 5Y3G, full-wave output pentode; and Brimar type 80 rectifier. rectifier. THERE IS A COMPLETE RANGE OF BRIMAR VALVES TO SUIT EVERY RECEIVER DESIGNED IN AUSTRALIA, FROM THE EARLIEST TO THE LATEST MODELS. BRIMAR DISTRIBUTORS LISTED BELOW: H.S.W.: Standard Telephones Ii Cables Pty. Ltd., 258-274 Botany Road, Alexandria. QUEENSLAND : Trock$on Bros. Pty. Ltd., 157-9 Elisabeth Street, Brisbane. SOUTH AUSTRALIA : Radio Wholesalers Ltd., 31 Rundle Street, Addaide. WESTERN AUSTRALIA: M. J. Bateman Ltd., 12 Milliga Street, Perth. VICTORIA: Noyes Bros. (Melb.) Ltd. 597-603 Lonsdale Street, M;ilbourne. TASMANIA: W. Ii w. Genders Pty. Ltd., 69 Liverpool Street, Hobart; 53 Cameron Street, Launceston; also at Burnie. HEW ZEALAND: Stondord Telephones Ii t.ables Pty. Ltd., P.O. Box 638, Wellington; P.O. Box 983, Christchurch. EV E R Y B R I MA R VA L V E I S 1 0 TIM E S T E ST E D. The Australasian "Radio World, February 1, 1940. DELTA APPLIANCE TESTER COMPLETE TESTS FOR JRONS, TOASTERS, FANS, GRILLERS, VA C U U M CLEANERS, ETC. Never before has the Electrical Trade received such con sideration with respect to their testing needs-with the IN ADDITION, THE APPLIANCE TESTER CAN BE OEl.TA APPLIANCE TESTER the practical electrician USED AS- can make tests of various kinds which require the rapid and accurate measurement of wattage, voltage and cur WATTMETER, Ranges rent. He can test Electric Irons, Toasters, Grillers., .0-25-100-250-1000-2500. Vacuum Cleaners, Fans, Refrigeration and Washing Machine Motors, etc., for both efficiency and leakage AMMETER, Ranges- to frame. 0-0.1-0.5-1.25-5-12.5. VOLTMETER, Ranges- The Appliance Tester is very simple ta operate and many applications will no doubt present themselves to 0-125-250. the user whereby the sale of, or repairs to, appliances Self-contained Neon Leakage Indicator and Continuity will quickly follow its installation. Tester. Independent Neon Continuity Tester. WEIGHT: 10 LBS. PRICE: £10/10/- Measurements: 9" wide, 8" deep, 7" high. (Complete with Accessories) Sole Australian Agents:- ~ .~ .... ;:, '· ';~'; .-r• .1 w. · G. WArSON .& ,CO. PTY .LTD. 279 CLARENCE STREET, SYDNEY. BRANCHES ALL STATES. T:li,!! Australasia.n Radio World, February 1, 1940.