Short Wave Radio

ItADIO NEWS U. S. AND CANADA AND SHORT WAVE RADIO

SHORT WAV E TIME Car TABLE Radio

THE RADI

A Publication Devoted to Progress in Radio Service Work Amateur Activity Short Waves Experiments Set Building Television DX Reception Electronics Applications Broadcastin www.americanradiohistory.comEn ineerin q sr

EXPRESSLY DESIGNED FOR Z/h1-31IMD iLs')L1Liti'D`28AlhAC=

METAL CASE CROSS BAR CENTER POST

VOICE COIL YOKE

A perfect magnetic path and per- A new G -E process projection Projection welding also prevents - manent alignment give crystal -clear welding results in a permanent misalignment of center post -a - and stabilized performance. and perfect magnetic path. source of many speaker noises. tone

MODEL A-82 The Stabilized Dynamic Speaker is but one of five major features bands 140 -410 8 metal tubes, four reception of Gen- k.c. and 540 -19,500 k.c. which contribute to stability in the life and performance eral Electric receivers. $94.60(Eastern List Price) ADDITIONAL FEATURES ARE: Metal Tubes -Strong and clear in signal. Supremely quiet - especially on short -wave broadcasts. Sentry Box - Controls as many as five separate broadcast bands - permitting only one radio wave to pass. Permaliners - Maintain the original factory adjustment of the set. Sealed against moisture and dirt.

Sliding -rule Tuning Scale-Shows only one tuning scale at a time -lists all stations in a straight line. As easy to read as a ruler. GENERAL ELECTRIC The Original Metal -tube Radio CONN. APPLIANCE AND MERCHANDISE DEPARTMENT, GENERAL ELECTRIC COMPANY, BRIDGEPORT.

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 513 I WILL HELP YOU START A SPARE TIME OR FULL TIME RADIO SERVICE BUSINESS J. E. South, President National Radio Institute WITHOUT CAPITAL Free Book Tells How dollars is being spent on two stations. Re- ceiving sets are being designed and built. Mail Coupon! New opportunities -many of them-are right ahead. My book tells you of the opportuni- The world -wide use of Radio sets for home ties in these fields, also in Aviation Radio, entertainment has made many opportunities Police Radio, Short Wave Radio, Automobile HERE ARE A FEW EXAMPLES for you to have a spare time or full time Radio and other new branches of this fast Radio service business of your own. The growing industry. Get it. day you enroll I start sending you Extra OF THE KIND OF MONEY Money Job Sheets which quickly show you how to do Radio repair jobs common in most I every neighborhood. Many N. R. I. men Train You at Home I TRAIN MY MEN TO MAKE make $5, $10, $15 a week extra in spare time in while learning. I show you how to install Your Spare Time and service all types of receiving sets. I give Hold your job until you're ready for another. you Radio equipment and instructions for Give me only part of your spare time. You Now Has Fine Business conducting experiments for building circuits do not need high and a school or college educa- "I have a fine business servic- testing equipment, and for making tests tion. Iundreds with only a common school ing sets. I am making a good liv- that will give you broad, practical Radio ex- education have won bigger pay through perience. Clip the coupon below and get my N. R. I. Graduate J. A. Vaughn jumped from ing- seldom have a week under free 64 -page book. $40. If it wasn't for N. R. I., I "Rich Rewards in Radio" $35 to $100 a week. Fred Dubuque doubled would probably be tramping the -it gives you a full story of the success of his earnings in one year. The National Radio streets." N. R. I. students and graduates, and tells Institute is the Pioneer and World's Largest how to start a spare time or full time Radio organization devoted exclusively Glenn C. King, service to training 46 Division Ave., S., business on money made in spare mien by Home Study for good jobs in the Grand Rapids, Mich. time while learning. Radio industry. Many N. R. I. Men Make $15 a Week in Spare Time You Must Be Satisfied "My spare time earnings $5, $10, $15 a Week Extra I will give you an agreement to refund every average $15 a week. Since study- penny of your money if you are not satisfied ing with you I have earned in Spare Time While Learning with my Lesson and Instruction Service about $7.000 to $8,000 in Radio. when you complete my Training. And I'll Many of the twenty million sets now in use not only give you thorough I owe my success to the good are less than 50% efficient. I will show you training in Radio method of the N. R. principles, practical experience in building I." how to cash in on this condition. I will and servicing sets, but C. N. I-lelfelfinger, show you the plans and ideas that have also Advanced Spe- R. F. D. cialized Training in the type of Radio work No. 1, enabled many others to make $5, $10, $15 a you choose. Temple, Penna. week in spare time while learning. George W. Honert, 248 Water St., Ligonier, Ind., made over $500 from the start of the Course Best Equipped Shop in Town to its completion. Get My Free Book of Facts "In the last year, we have Mail the coupon for `Rich Rewards in moved our Radio shop and we Get Ready Now for a Radio Radio." It's free to any ambitious fellow now have the best equipped over 15 years old. It tells you about Radio's Radio Repair Shop in East Business of Your Own and spare time and full time opportunities ; about Toledo. We also have a shop at my training ; what others who have taken it 624 Milton Street. We have for Jobs Like These are doing and making. three fellows working for us." Mail coupon now in an W. R. Brown, Broadcasting stations use engineers, oper- envelope, or paste it on 309 Main St., ators, station managers, and pay up to $5,000 a lc post card. Toledo, Ohio. a year. Radio manufacturers use testers, in- spectors, foremen, engineers, servicemen and buyers, and pay up to $6.000 a year. Radio J. E. SMITH, Pres. You Get PRACTICAL dealers and jobbers employ hundreds of Dept. 6CR EXPERIENCE servicemen, salesmen, managers, and pay up to $75 a week. Television promises many National Radio with Radio Equipment I Give You good jobs soon. Television is leaving the Institute laboratory in an impressive way. One million I'll show you how to use my special Radio equip- Washington, D. C. ment for conducting experiments and building circuits which ilhcstrate important principles 4cc used in such well -known seto as Westinghouse, General Electric, Philco, R.C.A., Victor, Atwater - Get my FREE LESSON '7his Coupon is good for One Rent, and others. You work out with your own hands many of the things you read in our lesson on Radio Servicing Tips books. This G0-50 method of FREE COPY OF MY NEW BOOK training makes learning at home I'll prove that my Training gives practical, easy, interesting, fascinating, in- money- making information, that it is easy to tensely practical. You learn how understand -that it is just what you need to J. E. SMITH, President, sels work, why they work, how master Radio. My sample lesson text, "Radio to make them work. Receiving Troubles -the Cause and Remedy" National Radio Institute, covers a long list of Radio receiver troubles Dept. 6CR, in A.C., D.C., battery, universal, auto, 'I'. R. P., super-heterodyne, all -wave, and other Washington, D. C. types of sets. And a cross reference system gives you the probable cause and a quick way Dear Itt', Smith : Without obligation, send me the to locate and remedy these set troubles. A Sample Lesson and your free book about spare time special section is devoted to receiver check -up, and full time Radio opportunities, and how I can alignment, balancing, neutralizing and test- train for them at home in spare time. (Please print ing. Get this lesson Free. No obligation. plainly.) Just nail coupon. MAIL COUPON NOW Name Age Address '7ü doutaáouff& World Famous Course that Pays For Itself City State 14x1

www.americanradiohistory.com Edited by LAURENCE MARSHAM COCK.ADAY

S. GORDON TAYLOR WILLIAM C. DORF Managing Editor Associate Editor

JOHN M. BORST JOHN. H. POTTS Technical Editor Assoc. Tech. Editor

JOSEPH F. ODENB ACH Art Edito, Vol. XVII March, 1936 No. 9

516 1 Serviceman's Diary Anonymous keading Cuide 2 Radio Facts and Oddities H. T. Elmo 517 to this Issue- 3 5 -Meter Car Radio Laurence M. Cockaday 519 AMATEURS -3, 4, 6, 7, 8, 9, 10, 4 What's New in Radio William C. Dorf 521 11, 16, 17, 18, 27, 28 8, 19, 522 BROADCAST FANS -2, 4, 5, 5 How Radio Advances 1 By Leaders of the Indùstry 20, 21, 24 524 DEALERS -1, 3, 4, 5, 8, 9, 11, 13, 6 Armstrong's New Transmission System (Part 2)...Dale Pollack 14, 15, 17, 25, 2S M. Walker 526 DESIGNERS -3, 4, 5, 6, 10, 11, 17, 7 The "Ham" Shack Everett 18, 19, 28, 30 -Installed Antenna Mast The Staff 527 DX FANS-S, 16, 19, 20, 21 8 An Easily ENGINEERS -3, 5, 6, 11, 17, 18, 9 The 5 -Meter Range Beckons S Gordon Taylor 528 19, 28, 30 529 EXPERIMENTERS -3. 4, 6, 7, 9, 10 Meter Switching for the "Ham" L. E. Grant 10, 11, 12, 13, 15, 17, 1S, 19, 25, 26, 28, 30 11 The R.N. 20 -Watt Amplifier (Part 2) ..J. H. Potts and J. M. Borst 530 -3, 5, 28 MANUFACTURERS William C. Dorf 532 OPERATORS -29 12 Radio Workshop SERVICEMEN -1, 4, 5, 6, 8, 9, 11, 13 Servicemen's Output Meters John Strong 533 12, 13, 14, 15, 16, 17, 18, 25, 28, 30 534 SET BUILDERS -3. 4, 6, 9, 11, 12, 14 The Service Bench. Zeh Bouck 13, 15, 17, 1S, 19, 28, 30 The Staff 535 SW FANS -4, 7, S, 9, 15, 19, 22, 23, 15 Crystal Service Oscillator 27, 2S Traffic Signal Noise J R. Steen 536 STUDENTS -1, 2, 4, 5, 6, 9, 10, 16 Eliminating 11, 12, 13, 14, 15, 16, 17, 18, 19, 25, 26, 28, 29, 30 17 3 New Metal Tubes (25A6, 25Z6, 6X5) Richard Purinton 537 TECHNICIANS -1, 2., 4, 6, S. 9, 10, 538 11, 12, 13, 14, 15, 16, 17, 18, 19, 25, 18 Impedance Matching Calculations (Part 6) C. A. Johnson 28, 30 19 Circuit Analysis of 24 -Tube Super Coming- L. M. Cockaday and S. G. Taylor 539 Among the articles for service- 20 The DX Corner for the Broadcast Band S Gordon Taylor 540 men next month will be one con- S.) J M. Borst 543 tinuing the discussion of output 21 B. B. Station List (N. American except U. :meters which begins in the pres- Corner for Short Waves L. M. Cockaday 544 ent issue; also one on adapting 22 The DX standard radio receivers to the 23 World Short -Wave Time -Table The Editor 546 needs of the hard -of- hearing through the addition of a micro- 24 Backstage in Broadcasting Samuel Kaufman 550 phone and headphone jack. This 552 field is a 'lucrative one which 25 Service Contest Awards The Contest Editor servicemen can profitably culti- Physics Course Alfred A. Ghirardi 554 vate. For the 5 -meter enthusiast 26 Students' Radio there will be several distinctly Captain Hall's Short -Wave Page Horace L. Hall 556 worth -while articles. Readers 27 with other interests including 28 The Technical Review Robert Hertzberg 558 constructors and experimenters will likewise be amply taken care 29 QRD? By GY 560 of in a variety of articles by well -known authors. 30 Super- Sensitive V.T. Voltmeter (Part 4) John H. Potts 570

Published Monthly by Teck Publications, Inc., Washington and South Avenues, Dunellen, N. J. AND EXECUTIVE OFFICES Lee Ellmaker EDITORIAL President and Treas. 461 EIGHTH AVENUE, NEW YORK CITY, N. Y. 25c a copy. Stìbscriptions: Entered as second class matter at the Post Office at Dunellen, $2.50 a year, $4.00 for two B. Holcepl and Foreign Secretary N. J., under the act of March 3, 1S79. Copyright, 1936, by years. In Canada Teck Publications, Inc., in U. S. and Canada. All rights reserved. Countries $3.00 a year, $5.00 H. D. Crippen W. P. Jeffery Registration of title of this publication as a trade mark applied for two years. Subscribers are Advertising Management for in United States Patent Office. Printed in the United States notified that change of address Virgil Malcher of America. The contents of this magazine must not be repro- must reach us five weeks in 205 W. Wacker Dr., Chicago duced without permission. We cannot he responsible for lost advance of the next date of Western Representative manuscripts, although every care is taken for their safety. issue. 514

www.americanradiohistory.com IZAI)IO A I AVS colf \Lvfc li, 193(i 515 Clay Bailey, Chief Radio Opera or Second Byrd Antarctic Expedition, ...gives high praise to great performance of MASTERPIECE receivers at "bottom of world "! It is a well known fact that the Byrd Expedition selected four MASTER- PIECE II receivers and took them to Little America. Now, the story of their really triumphant performance is told by Clay Bailey, Chief Radio Operator of Above. Chief op ?rotor Bailey, the expedition. in his furs at Little America. For a receiver to perform satisfactorily Left: Chief OperatorBailey,with under IDEAL conditions is ONE thing. Waite, John Dyer and Guy Hutchinson at KFZ in Little But for a receiver to stand up and give America. Under Mr. Bailey's brilliant, trouble - free performance right arm is one of the Byrd Er- ped i tion's four MASTERPIECE under the MOST DIFFICULT CON- II receivers. DITIONS possible to imagine -with little Lower Left: Chief Operator Bailey's report of MASTER- PIECE performance. 3981 Falcon Street, San Diego California, Hr. McMurdo Silver, November 13, 1935. 3364 North Pauline Street, Chioago, I111noie, opportunity for service or re- LOW PRICES! Dear fir. Silver: pairs an achievement which -is The new perfected MASTER- As Chief Operator of the Second Byrd Antarotio we believe is unequalled PIECE IV is now offered at LJpeditlon I fool that a word of praise and thanks is due you and your Corporation is regard to the satisfactory performance by any other all -wave radio. the lowest price in its his- of the four !!AZTS3PIECE II reoeivers which were the official tory, under a positive guar- all -cave receivers of the ¡pedition, one of which remained on the "Bear of Oakland" and one on the "Jacob Rupert ", providing Mr. antee of satisfaction or your the entire expedition eith regular home entertainment as well Bailey's letter is repro- money back. as s 'choice aeleotinn of foreign programs during their 30,000 or e0 males voyage to and from the bottom of the world. duced here, exactly as it came On the departure of our two veaeele from the Bey to us. Need we offer more of Shales for one long year, poeeibly two, contact with the EASY TERMS! oateide world depended solely upon radio to that body of men convincing proof of MASTER- who faced the cycle of Antarctic season. ne can readily New, liberal time -payment realize to what extent the broadcasts from home and the outside PIECE quality of design and plan enables you to enjoy orld contributed to the contentment and morale of the ice party. How comforting and consoling, snug In our little oity, workmanship?... or more sig- the thrilling performance of listening to the voices of our loved once, thousands of miles this superfine receiver NOW easy, al though eeperated only by s few feet, nificant assurance of what you ... and pay for it out of in- The familiar clang of "Dig Ben" from London, An may expect of the even greater come. Check and mail the addition to other choice programs from Europe, were regular morning features. From noon until early evening we Sere MASTERPIECE IV of today? coupon for details. naturally more intereoted in oroadcaste from home of which the volume and clarity was no question. For evening entertainment The coupon will bring you one, choice was of programs from South Mellott, New Laaland, Australia, and Japan as well as other Asiatic oountriee, a free copy of the 32 -page 30 -DAY TRIAL The oars and maintenance of these receivers wee "Blue Book," with complete Try the new MASTERPIECE of little or no eeneetuenoe. Little tttnge like a few drops and rough handling by the transportation department and drifting description of "the finest radio IV in your own home or enow on the trail oetween Little America and the &hips are barely worth mentioning. laboratory. If it fails to out- of all time," new low prices, perform any other receiver, A& thee. were the only all -wave broadcast receivers easy plan, 30- at any price, return it to our on the expedition I am Mire the crews of both ships, chile payment and wintering Hew Zealand, laboratory in In addition to the toe party, join me day home offer. Mail undamaged and in expreeeing appreciation to you and your Corporation for trial it get your money back. providing 0e eltb thie means of acrid-wide broadoaet entertainment. today. .. theié s no obligation. Sin HIGH -FIDELITY Clay ley, ;Chief Radio Operator, WORLD -WIDE Byrd', Seoond Jntarotie rtpediti on. ALL -WAVE SILVER MASTERPIECE rif

McMURDO SILVER CORPORATION, Div. G. P. H. Inc. 3352 N. Paulina Street, Chicago, U. S. A. Send Free "Blue Book" giving complete specifications of MASTERPIECE IV with details of 30 -DAY TRIAL. Send details of new Budget Plan of Easy Payments. Name Address City State a -RN RADIO OF ALL TIME!

www.americanradiohistory.com 616 RADIO NEWS FOR MARCH, 1936 Pages From Q

Aervicanan's VIAR Y TUESDAY -Stayed in this morning to take care of some shop jobs. The first one, an International midget, was weak (simply due to improper adjustment of the magnetic speaker). Took only a moment to fix. Found a blown filter condenser in the next one, also an International. The rectifier tube, as is usually the case, was ruined when the condenser blew. Checked the volume control with the ohmmeter. Also doubtful. Phone customer, recom- mending the set be traded in. Will let us know. NEXT -Stewart- Warner all -wave. Re- placed volume control and spent some time on the rubber -roller drive which slipped occasionally. Had no replacement rubber belt so removed the worn drive, built up the grove by winding a rubber band around it, then replaced the worn belt. Now O.K.! Meanwhile one of the fellows dropped in to tell about the new speaker design being tried out in the new Rockefeller church. Uses two dynamic cones, one in a large compartment enclosed with pipes arranged to resonate with and reinforce certain frequencies, the other in a shallower compartment alongside. Both compart- JAMMED FULL OF BOTTLES, LOVE LETTERS, NICKNACKS ments were inverted over a pool of water. end allowed the sound The young owner suddenly remembered the precious letters he had hidden away An opening at one and grabbed wildly for them. Was his face Red? waves to emerge only after being literally "baptized" in the water. Which seems a peculiarly appropriate design for use in larger and more modern radio to meet his Got the record -changer operating nor- a Baptist church. Either because of or present requirements. He agreed, and mally again, discarded all the warped rec- in spite of its design, the apparatus ap- asked me how much the biggest set we had ords and picked up the schedule again at parently proved a complete success in dif- would cost. Told him we had a. Cape - 4 p.m., reporting my location at the office. fusing the sound evenly throughout the heart at $1200 that had plenty of space in Pulled a Radiola 143 chassis, which gave cathedral. After all, the more conven- back. Said he would have it sent up. (No distorted reproduction due to a defective tional designs did not prove satisfactory. chance, however, since the managers of volume control. Struck a miserable buzz- Off for lunch, then out on calls. NUM- trust funds generally take even better care ing noise, blanketing reception completely, BER ONE -Large, beautifully furnished of other people's money than they do of at the next stop. Checked over the house- house. The estate of a man who, when their own.) Meanwhile took his order hold appliances and made sure that no one living, was a banker of national promi- to install a better mike for home record- was using an electric heating pad. All nence. Was ushered in to the presence of ing. Went downstairs and checked over a O.K. Looked out the window and saw a charming widow, who asked me first to Zenith combination, adjusting the push- a tropical fish aquarium in the next house. fix her son's set, then to go over the other buttons on the station selectors, picked up Went over and asked permission to test three sets in the house. Told me the boy another Zenith midget to replace the the aquarium heater. Sure enough -arcing would let no one go near his radio and volume control, then tackled the sweet job badly! Explained that the neighbors were that he got a great deal of pleasure tinker- of making a Stromberg record -changer run being subjected to interference from it. ing with it. Went upstairs and knocked properly after the youngster had jammed They were nice about it and promised to on a bedroom door. Was admitted by a the mechanism. Phoned the shop that I buy a better one. (Substituted an ordi- young fellow, about 18, who promptly wouldn't be able to hold to the schedule so nary electric bulb temporarily.) All O.K. locked the door after I entered. Told me our emergency man could "fill in" for a now. Bye -bye until tomorrow. he liked to play with the set, which was couple of hours. (Customers can let a set a Radiola 86, but that he had the wires remain inoperative for a week, but if a Noise Causes Deafness all balled up now and couldn't get a sound serviceman is half an hour late they feel out of it. sadly neglected.) CINCINNATI, OHIO-Believe it or not, continuous exposure to loud noises will A Hidden Cache cause deafness, due to damage to the nerves. This was the conclusion of Dr. Turned the set around and found the THESE records from an anony- M. H. Lurie of Harvard University. Dr. cabinet contained not only the set and mous serviceman's diary should Lurie has been experimenting with the ears power unit but also an additional high - be of decided interest to veteran of cats; he was able to connect a special of kind of radio hook -up to the hearing ap- voltage supply, consisting of two quarts servicemen, as well as to those 16- year -old rye and one large bottle of paratus of cats' ears. In such a way it was Scotch. In between the power transformer whose experience in the service possible to gain valuable information about and choke was plugged a large batch of field is more limited. Written by the causes of different kinds of deafness. perfumed letters wrapped in ribbon. All a man who "knows his stuff," and It seems that cats have all the varieties of placed deafness which occur in human beings. of which I removed and reverently shot with an occasional outcrop- along the floor. Found the voice -coil, link - Among the causes of deafness Dr. Lurie circuit open and the wires off. Repaired ping of humor, these items pro- lists unregulated noise over long periods and replaced wires on link, remembering vide many hints not found in text which may seriously injure the nerves by that the mike works only with the red books. More of these pages will which we hear. Explosions can dislocate the special hearing cells, throwing them off and black wire on the right -hand side. appear from time to time. Carefully replaced the bottles and letters, the vibrating membrane on which they suggesting that he really should have a rest.

www.americanradiohistory.com RADIO News FOR MARCH, 1936 517 FACTs a r d Walt (Send in your Radio Oddities to "Elmo" and see them illustrated)

,1/%i=i%lii, , !e!--- C ,,.. POLICE ANGELES = "O', OS ARE --- 4-4 - ®z. eí901D Ì' \1 "(INN SCIEJTISTS HAVE CTONE 11JT0 EO INK k1 EY CARRY IN DEPTHS OF EQ vE MAMMOtH CAVE, 1

L L

LESS THAN EST METERS F2oM CREST To cRESi IU(////, " rs , '1 `SHORT r WRVE 3 ) k) ,, _ >

HT5RM ONG-" WAVES AND 514OR WAVES HAVE WI BEMIRING ON THE DIS r9ACE IN MANY ENGLISH SCHOOLS, 'J9D(O THEY MAY TRAVEL NOR ONTNEIR POWER!! SOUND EQUIPMENT, WITH SPECIAL LOUD THE WAVE LENGTH IS MEASuREO FROM 11-k SPEAKERS AND HEAD SETS ARE INSTALLED CREST OF ONE WAVE TO THE CREST OF FOR TEACHING CHILDREN WHO ARE THE FOLLow INI - ONE`.'. `THIS %Y, /SEQUIN 1! (ARD OP KEARu t« G , MU ICI,.,

www.americanradiohistory.com RADIO NEWS moli MARCH, 1936 For the First Time Universal Application Now...6

MALLORY ; REPLACEMENT CONDENSERS service 100% of all *r,aio sets *radio sets using electrolytic Mallory Condensers are manufactured under U. S. Patents 1710073,1714191, et al. condensers For the first time, the service man is offered a practical universal mounting feature for carton type condensers. For the first time, the service man has available a practical universal mounting feature for round can condensers. For the first tune, the necessity for splicing leads has been eliminated. For the first time, absolute protection against humidity is afforded.

Here are but four of many constructional fea- of these condensers in every day service work. tures of the new Mallory line. But, over and It is the most valuable condenser help a ser- above constructional features, is a fifth feature vice man can have -the detailed analysis of - for the first time - the New Mallory problems submitted by over 29,000 service Condenser Service and Replacement Manual, men. Have you received your copy ? If not, which gives in detail the universal application write us today, on your business letterhead.

Cellophane separators - Etched anodes - P. R. MALLORY & CO., Inc. Stitched anode leads - INDIANAPOLIS INDIANA - of course, all important Cable Address- Pelmallo improvements pioneered or developed by Mallory are incorporated in Mallory Condensers wherever they add to quality. I

www.americanradiohistory.com Ii!Tews March, 1936 ÇJiveMeter CAR RADIO (Talk While You Ride

Many American amateurs have been having a lot of fun and gaining experience in the operation of portable -mobile radio installations by building and operating a 5 -meter radio telephone transmitter and receiver for their cars. The activities on the 5 -meter band have increased to such an extent, recently, that no matter where you drive there are always a number of stations you can contact along the path of travel. This article gives the details of construction of such a transmitter

T ELLO! W2JCY. This is By Laurence M. data on his transmitter and re- i-j1 W2IRT. I am speeding Cockaday "H ceiver for publication in RADIO along the Hutchinson NEWS. He said he would like to River Parkway from White Plains at about 35 miles per talk to me about it and I invited him up, although it was hour while I am talking to you. I am using my new then 1 o'clock in the morning. He started out to come 5 -meter portable -mobile phone transmitter. Are you re- to my home station (W2JCY) and we had an interesting ceiving me all right ?" duplex conversation on the way as I pointed out to him, That was the first transmission your editor picked up by radio, the proper turns in the road to take until he from "Tony" Landry's tiny radio- telephone installation finally arrived right at my door. Thus, the plans for this in his coupe, while talking to amateurs on the 5 -meter article were really made over the air. band. These conversations with Tony have continued The complete car -radio installation is made in two for about a month, from small metal cabinets in- many points in Westches- stalled in a shelf under ter County, while Mr. the back window, ARRIVING AT THE AUTHOR'S HOME as illus- Landry contacted my sta- trated. One of these con- This is how "Tony" Landry drove up into the editor's drive- tion direct from his car. tains a complete transmit- These way after a 72 -mile drive throughout which Ire had been interesting talks "steered" by a 5 -meter radio telephone conversation between ter and the other a su- over the air from a mov- the car and the home station. perheterodyne receiver. ing automobile to my own Other photographs and a home prompted this ar- diagram accompanying ticle, as many people this article shows clearly whom we had told of the the constructional details incidents asked how such so that anyone with a a set could be built and working knowledge installed. of radio can build one. Guided by Radio The Transmitter One night, about a The transmitter itself month ago, I picked Mr. consists of one 6A6 oscil- Landry's (W2IRT) sig- lator tube using a T.N.T. nals up while he was circuit, with another 6A6 about to start down Fort tube as a Class B modu- George Hill in New York lator, and a third 6A6 City and asked him tube as a Class A whether he would like to driver. The transmitting give me the constructional equipment is enclosed in a

www.americanradiohistory.com 520 RADIO NEWS FOR MARCH, 1936

Details of the coils for the transmitter are as follows: The oscillator plate - tank coil consists of nine turns of No. 12 or No. 14 wire; wound in a spiral the of an inch in diameter and spaced a distance of the diameter of one wire. This tank circuit is tuned by a three - plate 35 mmfd. condenser. The grid - tank may have 14 to 15 turns of No. 14 wire, wound in a spiral % inch in diameter and spaced a distance of the diameter of one wire. The circuit for this transmitter is shown herewith and the various parts are noted on the diagarm, together with their circuit constants, so that with the photographs and the diagram anyone handy with tools can build the transmit-

ter in a few hours' time. It will be noted that there is a compartment above and one below the chassis "shelf" so that the tubes and transformer are mounted above this, while the rest of ! the parts and most of the wiring are in the lower compartment. This construction tends to add to the stability of the transmitter and to eliminate feed -back THE COMPLETE INSTALLATION effects which might otherwise become a Above: Looking through the car win- hazard in the case of duplex operation. dow at .the compact 5 -meter transmit- metal cabinet 5% inches by 6 inches by ter and receiver with the microphone 12 inches. On the front panel are: the The Rod Antenna and loudspeaker in evidence. Below: tuning dial (at the left) with the two A single- button carbon microphone is The details of the transmitter equip- antenna terminals directly above; a used with the transmitter and good qual- ment. s.p.s.t. switch to cut on and off the B- ity reproduction is assured with a reg- plus supply for transmission- reception. ular telephone hand set. a microphone jack and a 0 -100 milliam- The antenna itself is mounted directly meter for checking operation. At the on the license plate rack, bolted and right -hand side of this cabinet is a 5- grounded in this way onto the frame. pronged socket for connecting a plug A single -wire feeder is tapped off this running to the power supply. B bat- rod direct to the antenna post on the teries are employed for furnishing the transmitter. The rod is. 52 inches long plate energy and the transmitter oper- and the tap is made 35/ inches from ates very well with B voltages as low the top end. This point is very critical as 100 volts and develops full power in adjustment and should be carefully with 275 volts on the plate. At the checked, for a difference of only % of present time B batteries are used and an inch up (or down) in this adjust- the oscillator is biased so that it draws ment will cause the signal to drop from about 60 milliamperes at 275 volts. The an R9 to an R5. Final adjustment of this transmitter has worked very success- tap- is made while contacting a distant fully with ranges from 10 to 20 miles, station duplex so that the receiving sta- with reports of R8 to R9 reception. Both tion can report at which point the trans- the transmitter and the receiver are suit- mitter is operating most efficiently. able for duplex operation so that the car The receiver employed is a super- can be moving along while the transmit- heterodyne using four tubes for head- ter is in operation and signals can be re- phone operation and to which may be ceived and transmitted at the same time, added an output tube for operation of as in a regular telephone conversation. the loudspeaker. (Tarn to page 537)

osc CLASS B C4 C1 MODULATOR DRIVER SW T3 6A6 T2 6A6 T4 THE CONSTRUCTION DETAILS o-- The photograph, above, shows the top view looking into the cabinet, with the tubes mounted in place. Below is the 04 0 G bottom view of the transmitter, show- S ing the plate and grid coils, the ó switches, jacks, resistors, condensers e0 E and tube sockets. 6A6 ó can 0

R2 R3 6V -NWAAMA- L2 B+ L4= 9TURNS NO.I4 WIRES/g/ LE- 14 TURNS NO.44 WIRE 1 R2= 4000 OHMS TRIMMER CONDENSER R3= 500,000 OHMS C1 - 0-30 MMFD. THORD. T 2557- C2 -0-45 MMFD. TUNING 3 PLATES T1= M I C.TRANSF'M'R. Ta CLASS B INPUT U.T.C. 29 C3-C4- 0005 MMFD. - C5= 5 MFD. a5V. T3= CLASS B OUTPUT U.T.C.33 R1 =. 300 OHMS, 0 -400 D.C. MILLIAMMETER

www.americanradiohistory.com RADIO NEws FOR MARCH, 1936 521 WHAT'S

RADIOZzZ TELEVISION IS SURELY Yes, there is something COMING -AND SOON ! Here is a demonstration of large -scale television reception recently made in new in radio! many utilizing the Karolus Ger- On this television -plate method. Insert shows relative size of and the following pages the picture compared to a human you will find important Aerial Kit An Attractive Table -Type Set inside information on To facilitate installation, the new At- The International "Kadette" model 60 water Kent doublet- antenna comes com- receiver, offers a 6 -tube a.c. -d.c. superhet newest radio and elec- pletely assembled. The parallel -pair transmission line is soldered to the antenna and tronic developments the center insulator and porcelain spreaders are attached to the antenna and By W. C. Dorf lead -in. Low -Loss Socket for Metal Super -Sensitive Photronic Cell Tubes A new photo -cell of the "dry- plate" The National Company introduces six type, to provide high current output is new sockets with Isolantite insulation which now made available by the Weston Elec- include the JX100 wafer type socket for trical Instrument Corporation. Known as the new RK2S and RCA803 power pen- the type 2 photronic cell, it is intended todes, a unique socket for the RCA954 primarily for use at levels of illumina- acorn pentode tube, two sockets for the tion so low that the regular photronic cell RCA955 acorn triode, a 50 -watt metal can not provide sufficient output for the shell socket and the new Isolantite wafer in a striking modernistic design with dual - purposes intended. wave band coverage from 70 to 545 meters. A Man -Sized Condenser The Latest in Microphone Mr. William M. Bailey, Stands Chief Engineer The new Amperite of the Cornell -Dubilier Company, is shown microphone stand in the accompanying photograph with non -sliding, ball- bearing clutch re- standing quires only % a special filled turn for a positive stop, beside oil paper condenser meaning as developed by the above company for that the stand level "stays put." The microphone moves up or down with X-Ray power purposes. It has a capacity smooth pneumatic of 0.06 mfd. and is action. The stand can designed to stand up be rotated without under a potential of 250,000 volts. loosening the clutch, a very desirable feature when it is necessary to rotate the microphone in a hurry. (Turn to page 568)

socket shown in the illustration for the octal -base metal tubes. The Newest in Power Rheostats The Electrad vitreous enameled power rheostats are ruggedly constructed for long life at rated current loads. The contact shoe of special metal graphite composition contacts the wire -wound element on the outside surface to insure smooth noiseless action. They can be used as speed con-

trois for small motors, temperature controls for vacuum tube filaments and as a general voltage or current regulator in the laboratory. The type 2X shown, is available in standard values from 1 to 2000 ohms in 25 watt rating. Other units are made in 50, 100 and 150 watt ratings.

www.americanradiohistory.com NEWS FOR MARCH, 1936. 522 RADIO

Short Waves as Regular Listeners' Fare By Larry E. Gubb I fully expect that for a great majority of radio listeners foreign short -wave programs a regular and important RADIO will constitute ow part of their daily listening schedules in 1936. The attention of American listeners has been focussed on the short -wave band Radio progress is not something which slowly by recent improvements in reception funda through such features as the all -wave sult of hundreds, if not thousands, of aerial, and the built -in aerial tuning system, and indus which make it possible to tune in more industry's leaders, both technical stations in all parts of the world than ever undoubtedly affect radio before; and from the other side by im- will proved short -wave programs, more broadcasts in English, and the installation of foreign better broadcasting equipment by wavelengths without danger of interfer- Big Opportunities for the stations. ence. Consequently, it is not necessary to Trained Serviceman hold this assigned wavelength down to a By Albert A. Ghirardi Radio Tubes Blazing Trail 10- kilocycle band width. This will permit The fact that the circuits of the new high- fidelity transmission to the extremi- receivers this year are more complicated in 1936 only ex- F. J. Wessner ties of the audible range. While than ever before, and that they have even By done with broad- Radio tubes again demonstrate them- perimental work has been more "gadgets" to get out of order than this time, there is no to selves to be the keystone of the radio in- casting of this type at the models of previous years, ought story provided by doubt that in a short time high -fidelity make the real live -wire type of servicemen dustry in the selling the near and all -metal types. No stations will be established in -the kind who make it their business to new glass -metal for a higher single development during the past future providing a source keep up to date on all new equipment -just other be- year could have acted as the basis for such quality of reproduction. shout for joy ! Now, more than ever type of a powerful merchandising campaign, such fore, the "screwdriver and plier" reason why to buy a new re- Perfection of Short -Wave serviceman will be forced out of the ser- a potent of ceiver. That radio tubes will continue to vicing picture to make way for the type Transmission business funda- blaze new trails seems assured. New tube By E. F. McDonald, Jr. man who is "up on his his circuits." types and improvements on present types The perfection of short -wave transmis- mentals" and "knows the will be definitely in the picture during sion has put within the reach of every Training Needed coming year. Where the science involved radio owner the means of becoming a cos- Advanced in radio tube research can lead remains mopolite. Eventually interchange of infor- in 1936 curtained by time. Strides which will open mation between nations will become a tre- By A. Pletman up new wonders of radio are expected and mendous factor in preserving world peace. The appearance on the market of com- if the past is any criterion, will surely be Because of these things among others, plicated multi -tube receivers, using as many made. Zenith this season has devoted a large pro- as twenty -four tubes, and the impending portion of its efforts toward giving the advent of television, means that servicemen Tubes for the Ultra -High public highly important improvements in must study hard and keep themselves thor- Acorn the short -wave features of its receivers. oughly informed on technical developments. Frequencies If they do not, they will find themselves By James Millen Radio as an Educational unable to diagnose trouble in customers' re- The growing importance of the ultra - ceivers, and they will quickly lose their short waves for both commercial and ama- Medium business. They must also keep their test use has greatly speeded the develop- By E. H. Rietzke to take care of new teur in edu- equipment up -to -date, ment of suitable equipment. Television, I believe radio is a greater factor tubes, new circuits and new acces- realize. The aver- types of facsimile, and high -fidelity transmitters for cation than most people sories. the ultra -high frequency spectrum are re- age person today has a better appreciation attention from the commer- of music and a wider knowledge of world Short -Wave Reception Greatly ceiving great advent cials and leading amateurs are operating affairs than was possible before the Improved successfully on wavelengths of one meter of radio broadcasting. The stratosphere By Tobe Deutschmann and below. Necessity is the mother of broadcast, the March of Time, outstanding With almost dramatic abruptness the and equipment has kept pace. musical programs, etc., brought into the have jumped our required invention, everyday short-waves Typical among important developments are home, take the listener out of the tuning range from 950 to approximately helped make fea- and into a world with which he acorn tubes, which have routine It 23,000 kilocycles! Many compromises were sible the design by National of a practical would otherwise have little contact. in receiver design to quickly of radio in necessary receiver for the range from 1 to 10 meters. seems to me that the future bridge this tremendous technical gap. Ob- education lies along such lines rather than precision in radio na- viously a new order of toward education of a more academic is necessary and the coming High Fidelity on Ultra -Short lines radio has a manufacturing ture and that along such will see short -wave reception greatly cannot be dupli- year Waves distinct function which improved through perfection of detail in By J. M. McNeil cated by any other means. equipment. With many years of of so- called high -fidelity receiving With the advent experience in precision radio production receivers appearing upon the market in the Amplification of "Millions" in Tobe Deutschmann Cor- it has become evi- behind us, the last two or three years, One Tube feels that it is in a particularly the present broadcast band poration dent that in By V. K. Zworykin fortunate position to meet these new con- definite obstacles in the path of there are A type of tube has recently been de- ditions. higher fidelity reproduction. The long dis- for its operation operating veloped which depends to Stay tances covered by transmitters an initial electron current Metal Tubes Here broadcast band with only upon directing Alvin Zinkan in the normal means of an appropriate electron opti- By separation causes intolerable by does the future hold for metal 10 kilocycles cal system onto a succession of sensitized What interference to receivers which have been tubes? Radio prophets have had many higher targets having a high secondary emission "opened up" for reproduction of an initial current sad experiences in this fast -moving and fidelity repro- ratio. In such a tube seem audio frequencies. Higher several million times changing business.. But two things is a sound basis of de- may be amplified are here to stay duction, however, instability. Multiplier photocells certain; metal tubes and will, therefore, not be de- without will still be in demand both velopment based on this principle have been built to and glass tubes nied. Recognizing that the assignments in for replacement and original equipment for en- have an output of 5 to 10 amperes per the broadcast band are too firmly replace the con- many years to come. About half a hun- and re- assigned, lumen and may some day are producing trenched to be unscrambled and associated amplifier dred radio set manufacturers of escape must be em- ventional photocell with metal tubes; some other avenue In addition to their extreme sim- receivers equipped answer lies in the utilization system. dealers are stocking them ployed. The plicity and excellent frequency response, wholesalers and of short waves. important feature for replacement sales. 1936 should show on the order of they have the even more conditions. Ray- Fortunately, short waves output is extremely low, a continuance of present characteristic that the "noise" a tube manufacturer, 7 meters have a transmission at small light intensities, a gain theon's position, as do not carry great dis- allowing, is rather than such that they to 100 or more in signal -to- is to supply what demanded This means that broadcasting may of from 50 dictate requirements. tances. noise ratio. to attempt to be done in two nearby cities on the same

www.americanradiohistory.com \ .

RADIO NEWS FOR MARCH, 1936 523

Trained Servicemen to Go Far By I-. E. Jenkins The days of guesswork. haphazard methods, hit- and -miss attempts to remedy troubles are forever past in servicing. ADVANCES! Skilful servicing has become an established and recognized part of the radio field. forges ahead as people watch. It is the re- Public demand for the best in receivers has brought about many changes in the mental ideas originating in the brains of the design and improvement of vacuum tubes and radio receivers. To keep abreast of trial. Here are some of those ideas which this advancement has necessitated alertness on the part of the serviceman. A vast trends during the present year number of new service problems always follows in the wake of progress affording unlimited opportunity for the serviceman. Those who fit themselves, who make Public- Address Work Radio periodicals are bringing timely and practical use of resources made available, are bound Increasing in 1936 data to those who must solve the to go far thousand -and in this permanently established By C. B Scott -one problems in servicing in- branch of the radio field. It is our feeling that the coming year tricate sets of today. Radio parts are made available in vi11 show progress in the field of sound widest variety to meet every The Future of reproduction along the lines of higher requirement, even to precisely matched du- Radio in fidelity, extended uses for public- address plicate replacements. But I for one still Education equipment and more standard public -ad- insist that radio servicemen as a group By J. E. Smith dress units. Special engineering will still have not as vet cashed in on their enviable Radio broadcasting is a new vehicle for be necessary for some installations, but the situation. The IRSM and National Tech- the dissemination of educational informa- public- address field is one which is adapt- nician movements, among others, cannot tion. Being a new medium, those who ing itself well to standardization. This will be too highly commended for bringing wish to use radio for purposes of educat- business ing the public be very important as the uses for public - methods to servicemen. After all, must adapt the method to address systems increase. a specialist is entitled to his fee. the means. Education by radio must at- tract the public because attendance is not Research Develops Service Short Waves Bring Japan and compulsory. Broadcasts like American Russia Town Meeting, War Against War, Radio Field Forum, Plays with a Purpose, fortunately, By H W. Sams By A. G. Hoffman are the Just as the automobile high signs that radio in education P. R. Mallory & Co., Inc., of Lrdianapo- came before good is coming of age. lis, Lrdiana, announce roads were developed, just so radio two new develop- sets Even such abstract subjects as "pronun- ments of unusual interest are ahead of the airways, but these are to servicemen. ciation" and "correct use of words" can One is the Service and Replacement being paved with powerful stations which Con- be broadcast, if appeal and incentive are denser Manual described as the first com- override static both day and night, winter and included. Washington boasts of such a plete books of its kind. It rounds out the summer. Dependable short -wave program. series of servicemen's manuals which we broadcasting is here. Receivers as far in- land have been compiling. The other is a new as Missouri and Arkansas are con- sistently NEXT MONTH universal line of replacement condensers receiving Japan from one direction We are asking further questions and Russia from the other, on other that offer many amazing engineering fea- while South subjects of interest to our readers and tures, such as universal application, smaller American stations boom through day and the ideas night. of another group of experts will sizes, and great efficiency. be given in the April Issue. Both manual and line resulted from research and development activities that followed the study of thousands of question- naires in which servicemen presented their condenser problems. Two w ` 'C A Real Future in Radio By F. L. Sprayberry Radio educational standards are grad- ELECTRON ually being brought to a higher level. The young man choosing radio as his profes- sion can no longer take general radio train- TUBES ing and expect it to qualify him for any position in radio. Minimum educational By S. requirements are at least two years of high Kaufman school -more high school or college training simply means AT separate demonstrations before the that a young man's Institute chances for advancement are greater. of Radio Engineers, two Radio has many fields new electronic tubes were recently of opportunity. Se- revealed lect the one you like best and by Dr. V. K. Zworykin and specialize in Philo T. Farnsworth, it -that is your best assurance for a real well known tele- future in radio. vision inventors. Considerable attention of the radio industry was accorded the A Specialist Is Entitled to His two products. The RCA development was described before a New York I.R.E. Fee assembly while the Farnsworth By Charles product Goleopaul was explained to the Washington Chap- Skilled Specialist- that's the deeper sig- ter of the same scientific body. nificance of the title, "Radio Serviceman." Dr. Zworykin, Mr. Louis Malter and And tomorrow that specialist will have Dr. George According to RCA spokesmen, the tube learned A. Morton, of RCA, described marks an how to charge for specialized skill, their firm's new device termed advance in the utilization of for it is in a keener an "elec- what laboratory men business sense rather tron multiplier" at the New call "secondary emis- than further technical York session. sion." This is a capability that prog- The tube was said to hold definite principle by which the ress must be scored. Future advan- impact of electrons emitted radio ser- tages in the further development of tele- by a cathode vicing must be profitable as well as fasci- vision. release other electrons, from a series of nating. But its possibilities in other succeeding Remember, specialists are paid branches of radio electrodes, in ever increasing for brains were also declared to volume. The rather than hands. Meanwhile, be enormous. Experiments valve may be provided with set and parts manufacturers indicate appli- a photo -electric fully appre- cation of the valve to any task cathode or the customary ciate the recent transition of electri- thermionic cathode of the from tinker to cal amplification requiring exceedingly type used in technician. They are catering tubes of average receiving sets. as never high gain at noise levels far below the A photo- before to recognized servicemen, notably electric cathode was used in the tube present types of amplifier tubes. The tube demonstrated with endless literature, regional meetings, is suitable by RCA. test equipment for amplifying either d.c. or A neon and even factory training. a.c. of any frequency. glow tube connected to the (Turn to page 557)

www.americanradiohistory.com MARCH, 1936 524 RADIO NEWS FOR FREQUENCY MoDULATIoN ARMSTRONG'S (For the seduction

In the first of these articles covering mizing disturbances in radio communication RADIO NEWS-the principles of frequency mitter was described. In the present discussed, as well as the means by which range of ultra- short -wave communication By Dale Part

transmit- AN AMATEUR SET -UP These signals have been transmitted result. A new medium -power of heavy lightning ter making use of the frequency -modu- installation embodying the flawlessly in the midst A complete storms, when reception from a 50 -kilo- lated system is now being constructed. principles of the Armstrong receiver will reveal still Saden- watt broadcast station only 20 miles It is believed that tests system at the home of Harry in performance water of Haddonfield, N. J. distant was severely marred by the greater improvement static crashes. Such reception with the over the present systems. ordinary amplitude -modulated system, The apparent disadvantage of the new HE transmission distance for very even at high frequencies, is only ob- signalling method, which may prevent high- frequency signals has been tained under exceptional circumstances. its adoption for a time, is its com- T limited by the fact that these It should also be pointed out that the plexity. Undoubtedly simplification will waves are not reflected by the Kennelly - results obtained with the Armstrong take place, but for the present it appears Heaviside layer. Consequently, very method were all with the use of a simple that it can be applied only for point - high -frequency signalling is carried on dipole antenna, with no intentional di- to -point service by commercial commu- (except under freak circumstances) by rectional characteristic. nication concerns. Whether it will be the direct sky wave, which travels in widely used for broadcast reception in nearly a straight line from the antenna. 21/2 -Meter Demonstration the future is as yet a matter for con- Regular communication has been lim- At the meeting of the Institute of jecture. ited to transmission between stations in Radio Engineers, on November 6th. The Receiving System view of each other, the maximum dis- 1935, at which the frequency -modulated tance over which communication could system was disclosed, a demonstration The simplified circuit diagram of the be accomplished being dictated by the transmitter located about 20 miles from receiver which is employed is shown in curvature of the earth. Some recent . the Engineering Societies Building in Figure 5. While this receiver makes studies of the properties of the iono- New York, where the paper was read, use of a multiplicity of tubes (there are sphere indicate that the direct wave is operated successfully with an antenna twenty -seven in one model), most of diffracted in the upper atmosphere, and, power of only 100 watts. The Engi- these are part of the sensitive super- consequently, this conclusion must he neering Societies Building is located in heterodyne receiver which precedes the modified. but, by and large, reliable midtown Manhattan-hardly a favor- frequency -modulation detection scheme communication at ultra -high frequen- able situation for a demonstration broad- and which is shown in the first box in cies -until the frequency -modulation de- cast -but excellent reception was ob- the diagram. This receiver, of advanced velopment-had been limited to short tained. The system was operated at a design, makes use of 2 intermediate fre- distances. To maintain communication wavelength of 2.5 meters. This is an quencies, the first at about 6 mega- over larger distances, directive antennas example of the improvement in service cycles, and the second at 400 kilocycles. or high -power transmitters had to be area and economies in power that could The output of the last intermediate- constructed. Armstrong's contribution in suppressing receiver noise, and thus increasing the effective sensitivity of re- LOW ceivers, has increased the distance over SUPER -HETERODVNE CURRENT I.F. which reliable communication is feasible. RECEIVER INCLUDING LIMITER PASS AMPLIFIER 2ND.I,F AMPLIFIER STAGES FILTERS More Distance -Less Noise The results that Professor Armstrong has obtained by the use of the wide - T1 modulated system have EI band frequency LOUDSPEAKER AMPLIFIER .tiWtiti,titi successful. Consistent high - 0 o n-A been highly LI CI RI has been main- DIODE quality transmission RECTIFIER tained over a distance of some 85 miles AUDIO over an extended period of time on a AMP 2- LIFIER frequency of 41 megacycles with a DIODE R2 the top of RECTIFIER L2 C2 kilowatt station located at ooQ.--AKTA the Empire State Building. It should O AMPLIFIER E2 be pointed out that. with the transmitter at a height of 1000 feet, 85 miles is T2 about twice the ordinary "line -of- sight" FIG.5 distance over the surface of the earth.

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 ON ULTRA SHORT INVENTION of ladio `Disturbances)

Edwin H. Armstrong's invention for mini - -which appeared in the February issue of modulation were outlined and the trans - article, the operation of the receiver is disturbances are avoided, thus increasing the beyond the limitations of present systems Pollack Two

frequency amplifier is passed to the cur- ing between 350 kilocycles and 450 A REVISED TRANSMITTER rent limiter stages, each of which is kilocycles due to the presence of the A view similar to that employed in the trans- of the second transmitter mod- frequency -modulated signal (these fig- ulating equipment, mounted on tables, mitter. The current limiters (saturated ures are illustrative; several combina- at the Empire vacuum State Building, show- tubes), whose action is similar tions have been used in practice), one ing the various multiplexing circuits to that of a fast a.v.c. circuit as incor- of the circuits is tuned to 350 kilocycles, of the llrmstrong system. porated in the receiver, have a dual the other to 450 kilocycles. Note that function. In the first place, they elimi- the intermediate amplifier must be de- nate any amplitude variation which may signed to have a 100- kilocycle band- means by which this communication have been introduced into the signal width. method reduces disturbances. It has between the transmitter and the i.f. been pointed out that until the develop- amplifier output. Such amplitude mod- How It Works ment of the frequency -modulation ulation can result from noise or fading. Figure 6 shows the variation in reac- method, the only available way to ex- The second function of the current lim- tance of each of the tuned circuits; in tend the range of communication at very iters is to produce a mirror image for the range within which the detector op- short wavelengths had been to increase each disturbing frequency, on the oppo- erates the variations are nearly linear. the power of the transmitted wave by site side of the carrier. This will be de- The voltage for the two amplifiers is the use of directional antennas, or by scribed later. taken across the condenser and induc- high -power transmitter apparatus. If, on the other hand, attempts The Detector tance in each branch. Figure 7 illus- were made trates the variation in El and E2 to increase the range by increasing the After being amplified the signal volt - (which are the voltages admitted to sensitivity of the receivers, it had been age passes to two resonant circuits, each each of the amplifiers) with frequency. found impossible to do so without sim- consisting of a resistor, a condenser, After being amplified, each of these ultaneously increasing the noise level. and an inductor in series. One of these voltages is fed to the linear diode recti- To be effective, an increase in receiver circuits, say Li, Cl, 121, is tuned to the fiers, whose outputs are combined by sensitivity must be accompanied by an lowest frequency of the frequency- the transformers, Tl and T2. The improvement in the signal -to -noise ratio. modulated signal, the other, L2, C2, R2, transformers are so poled that fre- This is what the wide -band, frequency - is tuned to the highest frequency. Thus, quency variations produce a cumu- modulation method accomplishes. if the intermediate frequency for the lative voltage in the output, as shown in carrier is Why It Reduces Noise 400 kilocycles, which is swing- Figure S. It has been found that the relation between frequency and output Noise inherent to the receiver results voltage (Figure 8) can be made linear, from electronic effects in the early am- and thus an excellent means for detect- plifier tubes, and from thermal agitation w ing a frequency -modulated wave has noise in the first tuned circuits. That been devised, for, as the transmitter part of the noise which is due to ampli- FREQUENCY frequency swings under the influence of tude fluctuations is eliminated directly Q 400 i KG the frequency by the stages of current limiting in the 350 450 modulation, the voltage - across the output varies accordingly. receiver. When no carrier is being re- FIG.6 The transformers, Tl and T2, are fol- ceived, the noise is distributed through- lowed by a high -quality audio amplifier out the band over which the amplifier and loudspeaker. operates, in the case illustrated in Fig- There remains the explanation of the ure 6, over the 100- kilocycle band from 350 to 450 kilocycles. When a carrier is superimposed upon the noise, the situation changes because the E components F I G. 7 of noise, in the band -pass of the amplifier, beat with 350 400 the carrier and greatly a 450 KC. increase the noise appearing at the F FREQUENCY out- D o 440 put. This effect can be noticed with > 390 any receiver; there is always a large increase in the noise level FREQUENCY FIG.8 when an un- 350 400 450 KC modulated carrier is tuned in. (In addition, the detector sensitivity is increased by the (Tww to page 573)

www.americanradiohistory.com 1936 526 RADIO NEWS FOR MARCH, The 'HAM" Conducted by Everett M. Walker Editor for Amateur Activities Shack

angle is too great, of course the signals will go off into space, leaving only the ground wave effective. STATION several of the pioneers who were still observations are FAMOUS CHICAGO they Now, if the writer's active on the band reported that seem that these usable This is the "Ham" Shack of Alice R. distant contacts. correct, it would of Chicago, Illinois. again were establishing skip periods follow in more or less the Bourke, W9DXX It may have been that the band ap- sun- fine array of receivers at same cycle as sun -spot activity. The Notice the peared to go dead during this period be- years, of the operating table with spots occur in periods of eleven the back cause of insufficient activity. But, this is a period the on the left. waxing and waning during such transmitters not likely. It is the writer's theory that Right now we are in to peak and minimum. these DX periods, so- called, appear of maximum activity. are re- approaching a period cycles-cycles that in some way is tending toward greater It has been The cycle now lated to sun -spot activity. sun -spot activity. It might be pointed out Ten known for some time that there is some when a number of amateurs ionosphere (some- that in 1928, relation between the were obtaining real DX on 10 meters, we times called Heaviside layer) magnetic through a phase of the cycle The relation of were passing storms and sun -spots. that was similar to that we are now "skip distance" to high- frequency radio M ERS known. The having. signals is quite generally latest theories indicate there are three Will the Band Last? a layers in the ionosphere, each giving the question is: Is the 10- angle and varying in Therefore, "cCively different refraction meter band good during a period of small according to the fre- reflections properties sun -spot activity? That is something the quency utilized. Now, on the 10 -meter able to determine by the necessarily has to be amateur will be band, the ionosphere increased activity on the channel. It will DURING the last two months the reasonably low (it varies in height between band has become be interesting to see if it is true. But, in 10-meter amateur fifty and 400 miles) in order that it might mean the band is active. It has opened up, frequencies back any event, it does not tremendously reflect these ultra -high nor that it will be usable during and there is DX galore to be had with to earth at an angle that will fall tangent useless, and receiving several year periods. In periods of "poor the proper transmitting with the earth's surface, or less. If the local band. During a matter of fact, for the skip" it is a desirable equipment. As like 5 an ever - these poor periods, it is somewhat last year there have been L.P.O. WITH A TRANSMITTER but to a lesser number of stations on the meters; it is quasi- optical, increasing Jose Perez of Santiago, Dominican the latter band, and it covers and when conditions have been at the microphone degree than band, Republic is shown the valleys better than the higher f re- "right" contacts over several thousands of his station, HI4P. quencies. of miles with small amounts of power the With the in- With more activity on the band, have not been uncommon. obtaining this information are of stations operating on chances for creasing number increased. More and more stations are it, more and more is being learned about re- taking a fling at 10 meters. They are the necessary types of transmitters, Some have worked antennas. finding it interesting. ceivers and better distances than possible with the same 14,000 kilocycles, and have 10 -meter band is equipment on JUST how reliable the reports. The band, as far is still a moot question. The received better for DX DX is concerned, is a daytime band. writer has a theory that the tremen- as to- The largest number of stations are to be dous distances that are being obtained and international only a ques- found on it on Sundays day may not last, but this is generally follows when there be answered by the ex- holidays. It tion that can a short skip on 14,000 kilocycles, the tended use of the channel. It might be is about eight years ago 10 -meter band is "good." recalled that just Increased activity also has resulted in the 10 -meter band was "hot." There were on necessary anten- amateurs operating exten- valuable information several Eastern nas, transmitters and receivers. New- on it and accomplishing phenome- sively comers to the band have found it difficult nal distance work. One station in New effectively. regu- to get a transmitter to work Jersey as early as 1928 established is far more impor- with a sta- To begin with, antenna lar scheduled communication than power, and even more so than in Africa. Then the band tant tion South on 20 meters. seemed to go dead. Then. about a year ago

400 .0004 50 4 %SDIA.FORM L3-4TURNS-140.12-4 %¿DIA.FORM 400 .0004 400 .0001 TURNS 40M. MFD. MMFD MFD. MMFD. L2 - 44 DATA L44 - '-' ' " CRYSTAL MMFD. MFD. MMFD. L56 - y4 174 RFC. 20FÁ.' RFC 11 "804 4 . WITH 4' RFC. ` 2044. r .0004 400 0 -35 802 SPBP.ICNIÑG 59 1 as It 14° 53 MFD. MMFD. MMFD L3 L4 801 1-5

35MMF0. PEN SECTION lob 25 MMFD 5004,77g O110MS 20,000 OHMS 4OM. 5000 OHMS ORD.FD. +600 -B +100 +400 -90 FIG.2 FIG. I +350 -700 +600 -loo +600

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 507

(g A Department Steel for the amateur operator to help _(4iitennrr him keep up -to -date

In general, it has been found that a half - MAST wave doublet is about as effective as any antenna that can be erected for 10 meters. A majority of the stations are using varia- By G. Frazer tions of this system. It would appear, judging from the results obtained by most OCCASION was recently found to in- stations on the band, that a horizontal stall a new antenna mast at one of antenna is the most effective. This may the New York Listening Posts. The be due to the fact most receiving antennas type selected proved so eminently satis- are horizontal, and naturally are more ef- factory that it is being brought to the fective in receiving horizontally polarized attention of readers who may be faced waves. The radiation pattern from a with the problem of erecting a suitable half -wave antenna, of course, provides the antenna. greatest amounts of radiation in the two directions at right angles to the axis of the THE type antenna mast selected for antenna. Therefore, its erection direction our new antenna installation was the is important. Premax Telescope Mast. This consists of four tubular steel sections of gradu- The Johnson "Q" ated diameters, finished in dark -green enamel. As for feeding the horizontal doublet, Normally the mast is mounted on any of the accepted methods any type of roof, whether flat or sloping, may be used. by These are three: matched impedance volt- means of a pair of adjustable steel age fed; twisted -paid flanges attached to the bottom end of the matched impedance base and the transformer or Johnson "Q" section. For apartment -house installa- method. All three tions, such as that at the Listening Post are effective. It might mentioned, be pointed out that a station on the West there is a special Premax Coast has done considerable parapet support which permits the mast experimenta- to tion with different types of antenna, in- be mounted at any convenient point cluding beams, diamonds, atop the parapet as shown in Figure 1. etc., and was This heard to say recently that he has four- section mast has an overall always length, extended, returned to his Johnson "Q" for the best of 13 feet and a closed results. length of approximately 3% feet. Another type of antenna which should (Turn to Page 565) give excellent results but on which complete data is not Europe begin coming usually available, is two through at about 8 low about the same trend in half -wavelength antennas a.m. on Sunday morning and other sections operating in other days Furthermore, there is no means of fore- phase. This type of aerial is less when these stations are free to direc- operate. casting when the 10 -meter band will be tional than the half -wave type. Sometimes it is as late as 9 o'clock It merely before good. Some Sundays it will be excellent, consists of two half -wave Zeppelin they begin to filter through. Stations anten- to and on others no distant signals may be nas strung end -to -end and fed in the middle the West begin coming through shortly heard at after noon (on all. Some study of sun -spot phe- with a common pair of feeder wires. It the East Coast) ' and seem nomena might to arrive give some clue as to what might be called a current -fed 20 -meter at a peak at about 4 p.m. The may be expected times given here for a given time, but antennas. This type antenna provides good are Eastern Standard this would not always follow. radiation in four directions Time, and of course, conditions In general, at about forty will vary it seems that with a sudden increase degrees to the axis in the different time zones, in of the aerial wire. but should fol- the sun -spot curve, short -wave radio im- proves. Height Above Ground WORKS ALL BANDS Sun- spots, in addition to following the general eleven -year cycle from time The height above ground is Here is a rig in the "Ham" Shack also impor- to time, show increase for a few days at a tant. It is something that should of G. G. Peterson (Ih9JPJ). His time. be ex- transmitter At such intervals it has been found perimented with until the best results are operates on all wave- that instead of improving high -frequency obtained. One station in the East has bands from his home town of Car- transmission, they have found bondale, the contrary effect that it is desirable to tilt the an- Illinois. and have been known to cause complete tenna in the direction it is desired to dead spots. Also, another factor enters "spray" the signals. Between 30 and 45 into the problem of forecasting degrees will give conditions. the most marked direc- That is magnetic storms. These, too, tional characteristic. The station are in ques- generally accepted as being related to tion tilts the antenna toward Europe in sun -spot activity. But, unlike the morning and the effect toward the West Coast in the spots have on the ionosphere, which the afternoon. appears to follow in step with It is impossible to predict the sun -spot when the 10- cycles, the magnetic storms seem to be meter band will "open" up during any one further removed from lay, but observation the cause. That is, over an extended they do not seem to follow immediately period seems to indicate that stations from (Turn to page .572)

40M. .0004 .0004 .0001 CRYSTAL MFD. MFG. 11I 46 40 METER ANTENNAS RADIATION PATTERNS hI2/l--.1 tro r I r-/2T-1 ma -I+ 2. 400' OHMS FW- _OHMS * 3á t t 20,000 45,000 , OHMS OHMS 3 WF \` 04 % M FD 04, M FD. ANTENNA'/ MATCH ED TWISTED JOHNSON o. IMPEDANCE PAIR +350 ooa% O o o Q HALF WAVE FULL WAVE +400 +' + + + FEEDERS ANTENNA ANTENNA M FD. 45 ,350 90 4000 FIG.3 FIG.4

www.americanradiohistory.com NEWS FOR MARCH, 1936 S25 RADIO the Five -Meter

By S. Gordon E2 Taylor

The ultra- high- frequency ranges below 2.5 and 10 meters, are due to become nels, especially for television. Now is est himself in order to follow, or perhaps

or broad- the other amateur bands. ing on the regular short -wave TESTING 5 -METER RECEIVERS operation on In fact extreme sensitivity Second, for local contacts the 5 -meter cast ranges. Here the author is shown with some or high selectivity seem to be undesir- of the 5 -meter equipment to be de- transmitter will provide dependable low power as able at the present state of development. scribed in the articles to follow. Left communication with very does shown is: Peak by the fact that a num- The average 5 -meter transmitter to right, the equipment is demonstrated constant frequency and for "X -4" transmitter, Peak superhetero- ber of New York "hams" have worked not maintain dyne, Lafayette superheterodyne, Acra- in this that reason a receiver having extreme 400 or more 5 -meter stations a test super -regenerator (below) and the 5- selectivity would not be able to hold area. The great majority of Trans- the R -T -L super- regenerator. around New York signal from such a transmitter. meter transmitters of 50 to 100 considerably less than 10 watts mitter frequency shifts City put even more are not at all THE purpose of this series of into the antenna and many of them put kilocycles or 5- meters. Until such time articles is to provide some general a- fraction of a watt. The ma- uncommon on out only are developed to the information on ultra -high fre- jority of such transmitters employ re- as transmitters of employing crystal control, M.O. quency radio, with special attention to ceiving tubes exclusively. In fact the point bene- P.A. or other means for stabilizing fre- the 5 -meter amateur band, for the 5 -meter transmitter that uses one or high selectivity will continue fit of experimenters who are unfamiliar more regular transmitting tubes is the quency, a distinct disadvantage. with this field; also to present specific exception rather than the rule. The to constitute information on available 5 -meter re- third reason for the popularity is found Super- regenerative Receivers ceiving and transmitting equipment for in the fact that this ultra-high- frequency Too much sensitivity is likewise a experienced 5 -meter enthusiasts. band provides a tremendous field for disadvantage in the average noisy loca- For the uninitiated it will be interest- the experimentally inclined. While 5- or at least is unnecessary because radio tion ing to know that 5 -meter amateur meter radio dates back several years of the interference from automobile (and commercial experimental radio) is it is still in a constant process of de- ignition systems and certain other types enjoying a tremendous growth in popu- velopment. Every month produces ap- -made static." Most of the New of "man larity. It is estimated that in the preciable advances in the art. During noise interference familiar on other York metropolitan district alone there these past years a great deal has been wavelengths, including atmospheric 5 "ham" are over 1000 active -meter learned but the field has not as yet ad- static, is not present on 5 meters but stations on the air and every large city vanced sufficiently far to be "over the unfortunately ignition noise is present in this boasts numerous experimenters head" of the novice who has perhaps in exaggerated form as are some other field. Not only that, but the suburban tired of the more conventional frequency forms of interference such as from high- and even rural sections boast numerous ranges and is looking for new worlds to frequency diathermy equipment, some 5 -meter signals. conquer. oil burners, etc. Definite values of re- The popularity of 5- meters is ex- Receiving Equipment quired sensitivity and selectivity have plained in 3 ways. First the equipment probably not been worked out but it recep- The requirements of receiver equip- necessary for transmission and is estimated that receiver sensitivity as com- ment for 5 -meter operation in some re- tion is extremely inexpensive 5 microvolts is superfluous. differ radically from those en- better than pared with the equipment required for spects present time there are two countered in the lower- frequency ama- At the teur bands and the short and long -wave broadcast ranges. This is essentially a y O.D. COPPER "local" band. Under ordinary conditions ROD OR over range greater NO.45 SOLID reception of signals WIRE than 25 or 30 miles constitutes real DX. NO. IS OR FEEDER AT 1,10.14--WIRE RIGHT On the other hand, good stable com- LEAD-IN ANGLE TO good signal intensity ANTENNA munication, with N 0.12 OR TO THIS even from low- powered N NO.14 can be expected WIRE ,POINT a radius of 20 to 25 stations within 'co will be expanded in O.D. COPPER miles. The ranges TUBE4/4 OR NO.ia time through the use of directional ----SOLID WIRE receiving antennas and MOUNTED IN transmitting and VERTI CAL through other developments which over- POSITI ON ,l 30° 8' come the tendency of 5 -meter signals to travel in straight lines rather than SPREADERS following the curvature of the earth. F I G.2 5 -meter receivers need not have any- FI G.4 thing like the degree of selectivity or sensitivity required in receivers operat-

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 529 unge Beckons Results of Tests on 5-Meter Equipment

ANUMBER of 5 -meter receivers are now under test in the RADIO News Listening Post OINÇ.f (shown on the opposite page), where they have been employed in regular two -way amateur contacts under the author's call, W2JCR. These receivers will be described next month in Part Two of this 10 meters, particularly those between series. Part Three will review 5 -meter transmit- some of the most important radio chan- ting equipment now available on the market, which within the next few days will be added to the time for the experimenter to inter - the present transmitter at W2JCR for tests. participate in, the development to come

types of receivers in general use. These ultra -high frequency unless one resorts to purposely avoid building -regenerative in too much are the super and the super- to the use of the "Acorn" pentode tube sensitivity. This has usually heterodyne types. Each type has its been ac- (954) and even then extremely high complished by avoiding the use of the staunch supporters and each type has gain is not to be expected. usual double -tuned i.f. transformers and its definite advantages as well as dis- The superheterodyne receiver has the substituting resistance -coupled i.f. advantages. The super- regenerative re- advantage stages of providing almost unlimited with the resistance and coupling con- ceiver has the advantage that it is sensitivity and selectivity. Strange as densers values so selected effective as to broadly particularly on 5- meters. When it may seem, it has been necessary, in tune each stage to the desired frequency. properly designed and operated it shows designing 5 -meter superheterodynes, to These intermediate amplifiers will good sensitivity. Perhaps its outstand- usual- intentionally reduce the selectivity and ly pass a band (Turn to page 565) ing characteristic is its peculiar tendency to reject external noise. Even when used in sections where the automobile of every circuit of your transmitter. traffic is continuous, the super- regenera- The voltmeter, in conjunction with tive receiver is not particularly suscep- Meter the four tap voltmeter switch, SW1, tible to ignition disturbance. Such a will read the voltage on the plate of receiver is likewise simple to operate. any respective tube simply by turning As against these conditions, adherents Switching the knob to the desired position. The of the superheterodyne type will point first tap is left open. The diagram of out 3 basic drawbacks to this type of Figure 1 is self explanatory. receivers. The super -regenerative de- or the "Ham" The milliammeter and its associated tector is inherently unselective. Further- switch, SW2, makes it possible to take more, when connected direct to the re- By L. E. Grant, a reading of the current in the plate ceiving antenna it radiates badly. Third, W1AHC circuit of any desired tube. As shown the operation of the super- regenerative in Figure 1, the first tap is open. The detector is characterized by a "rushing" second tap applies plate voltage to all AmLL of sound. strong signals us are interested in getting tubes, assuming that two or On this rush dis- the most three tubes appears completely but, on from any radio equip - are being used. Taps three, the other ent we four, and hand, it is very may purchase. This ap- five, put the meter in the much in evidence on plies especially plate circuit weak signals. The amplitude to meters. The big ad- of tube number one, two, and of this vantage of having separate three, rushing sound varies considerably in meters for respectively. Taps six, seven, and different super- regenerative different circuits is that one glance at eight, remove the plate voltage receivers, the panel accurately from depending upon the care put into checks the operat- tubes one, two, and three, respectively. the ing condition of the transmitter. design and adjustment. Claims are How- This means the plate voltage of any ever, it is not necessary to made that if a receiver is properly de- have an one tube can be removed without af- array of meters unless desired. Two fecting the rest of the signed, the rush (with no signal tuned meters, set in any way. two switches, and you have a Neutralizing becomes a simple in) can be reduced to a point close to complete, matter - inaudibility. However, practical, and highly versatile no fussing with wires or behind there are few 5- method of checking -panel meter experimenters that have ever been up on the operation switches to cut off (Turn to page 543) able to reach this ideal condition with- PLATE OF TUBE NO.3 PLATE out greatly decreasing the inherent sen- OF TUBE NO.2 PLATE OF TUBE NO.4 sitivity of this type of circuit. The Superheterodyne r- Recently super -regenerative detectors have been improved greatly through the use of a preselector stage. Such an d(..1Z) amplifier stage provides increased selectivity and, being connected between the detector and the antenna, effectively -,--- TUBE NO.4 TUBENO.2 TUBE NO.3 1 eliminates radiation. Sw2 SÑ/ It also, in many MILLIAMMETER TO ELATE instances, reduces the SWITCH VOLTAGE SUPPLY VOLTMETER SWITCH c+ "rush" when re- POSITION POSITION ONO. ceiving weak signals. This is NO.4 = ALL OFF not true NO.2= ALL ON in the case of all receivers having a NO.3. NO.4 TUBE MA.READING. FI G.1 NO.2.. NO.1 TUBE VOLTS NO.4- NO.2 ^ ^ NO.3. NO.2 preselector stage, however, because it NO.5- NO.3 NO.4-NO.3 ^ NO.6 -. NO.4 TUBE Bt ON ONLY. , SW1- 4 CONTACT TYPE is a rather difficult , , matter to obtain any t P.7- NO.2 SW2- 4 GANG, 8 CONTACT TYPE appreciable gain in a t.r.f. stage at this NO.8- NO.3

www.americanradiohistory.com 530 RADIO NEWS FOR MARCH, 1936 Servicemen ! How 16 20 -Watt f n PHONF, r Constructional data on the new Class last month. The unit employs an OF THE COMPLETED AMPLIFIER TOP VIEW is ideal for amateur modulation as Illustrating the compact and workmanlike design for the new "phase -inversion" amplifier, designed, built and tested in the RADIO NEWS Laboratory especially for ama- By J. H. Potts teur and servicemen's use. Part

schematic circuit of not required, channel B and its asso- conditions, without affecting the fidelity THE complete range. It this new 20 -watt P.A. amplifier ciated volume control may be trans- characteristic over the useful for amateurs or servicemen to ferred directly to the phase- inverter is important that no larger capacity point. build themselves is shown in Figure 2 tube by simply throwing switch 2 to be used at this is of standard and indicates the simplicity of the de- point b. The chassis employed input channels Channel C connects directly to the size, using heavy No. 16 -gauge steel, sign. Three individual Drill- two of which may be used phase inverter circuit and is intended and is fitted with a bottom cover. are provided, with the layout for microphones and the third for a for use with an external pre -amplifier, ing is done in accordance phonograph pick-up or pre -amplifier. but may likewise be used for pick -up shown in Figure 2. The two gain con- in the front of the Convenience and ease of connection are work when the turntable is already fitted trols are located power switch S1 in assured through the use of a 6- contact with a volume control. Switch 2 must amplifier, with the strip. Each alternate be on point a when using this channel. the center. Above the input terminal input terminal switch 52 so that the diffi- strip is located the channel terminal is grounded High Stability post. The tone culty of having to fasten three lugs or and the ground binding ter- The tone control is connected from control is on the top portion of the phone tips under a single ground out- addition, a sepa- the plate to cathode of the phase -in- chassis. Provision is made for five minal is avoided. In transformer rate binding post is provided for an verter tube and is therefore effective, put channels. The output -, 7.5 -, 5 -, 3.75 - external ground. regardless of which channel is used. is designed to match 15 Freedom from motor -boating and other and 1.25 -ohm loads in addition to a Flexible Input Circuits forms of instability is obtained through standard 500 -ohm transmission line. Since the 6A6 is composed of two the liberal use of resistance -capacity Wiring Suggestions triodes, provision has filtering. In all circuits, except the similar high -mu leads in the input cir- made to connect channels A and B screen supply to the 6C6 tubes, consid- In wiring, the been be kept well separated to simultaneously, to each input section. erable capacity has been used. The cuits should are screen filter circuit, consisting of a 1- reduce stray coupling. The filament As the output plates of this tube first. The up by megohm resistor and a .1 mfd. con- circuits should be wired in wired in parallel, sounds picked then be com- to these chan- denser, has a time constant of 1 /10th filter circuit wiring may microphones connected the resistors and by- are amplified and mixed in the plate second which is sufficiently fast to elimi- pleted. Finally, nels pass condensers are wired in, using circuit before passing on to the phase - nate motor- boating under these design inverter tube. Separate gain controls are provided for both channels A and B to facilitate proper mixing. In addition, for phonograph pick -up amplification, where the increased gain of the 6A6 is

UNDER CHASSIS VIEW This view of the amplifier taken from below shows the general idea of assembly and wiring.

www.americanradiohistory.com RADIO NEWS FOR MARCII, 1936 531 cAnateurs! 6BB UILD ThT Amplifier and P. A. WORK

A RADIO NEWS Amplifier described outstanding type of circuit which +10 well as for service applications +5

2D6 and J. M. Borst 5 1030 100 Two 1000 40,000 FREQUENCY FIG.3 small terminal strips located close to the more light on the TESTING THE UNIT FOR FREQUENCY RESPONSE sockets. After the wiring is completed, subject seems de- the voltage The view above was taken in the RADIO NEWS Labora- adjustment of the phase - sirable. The gain tory while the authors were running inverter tube may be undertaken. their tests for audio The of the amplifier was response. The curve indicates the high- quality repro- slide on R22 should be adjusted until 102 db. This was duction that the amplifier is capable of delivering. the voltage between point C and ground measured with the is approximately 26 volts. Next, put a volume control milliammeter in the plate circuit of the "full -on" and the amplifier delivering 20 characteristics of rectifier 76 and readjust the slide the -type until the meter watts to a 500 -ohm load, at 400 cycles. meter. The frequency characteristic reads 1.4 ma., approximately. Point D, is In practical language, this means that it shown in Figure 3. It is essentially flat for the screen voltage, is taken at 250 takes .025 volt at the input terminals to throughout volts. the audible range. At 18,000 deliver full output. The circuit used for cycles it was .7 db. down, at 10,000 Measured Characteristics the purpose of this measurement and the cycles .4 db. down. On low notes good frequency characteristic is shown in Fig- response is obtained; at If the amplifier is to be operated 80 cycles it is over ure 4. The resistance, R, of 150,000 .9 db. down, at 50 long periods, longer tube life, particu- cycles 3 db. down ohms, was placed there to simulate the and at 30 cycles 6.7 db. larly of the 6B5's, may be down. When obtained by internal impedance of any signal source the first stage is cut using less than the maximum plate out, the voltage volt- one would employ. One hundred and gain is reduced 10 times, so age of 400 volts. A reduction the total to ap- fifty thousand ohms was chosen as the gain of the amplifier is proximately 350 volts is accomplished then 82 db.; it average secondary impedance of line -to- takes .25 volt at by simply omitting Cl. The power the input terminals for out- grid transformers. full 20 -watt output. This arrangement put will, of course, drop slightly but will The frequency characteristic was mea- will generally be preferred with the be sufficient for practically all purposes. sured with the same set -up, The shown in average phonograph pick -up. amplifier's performance was mea- Figure 4. This was taken also at full sured in the RADIO NEWS Laboratory gain and with the amplifier delivering Hum Level in the usual way. Since it appears from 20 watts to a 500 -ohm load. The vac- The hum level is 40 db. below maxi- many letters that some readers have uum -tube voltmeter and the rectifier - mum output 1 volt difficulty in interpreting the meaning -or across the 500 - of type meter were checked against each ohm load. One should be careful the usual engineering graphs, a little to other and corrections were made for the shield input wires and to ground the shields of input transformers, etc., to eliminate any possibility of hum pick -up by induction. 6C6 C44 Finally, some cathode -ray tests were made. The first one was a test for harmonic C43 distortion. It was made by ap- 00 OHMS plying the input signal to one set of deflecting plates (Turn n ' to page 536) 15 OHMS 7.5 OHMS THE TEST CIRCUIT USED S OHMS This is the general layout of the test 3.75 OHMS method 1.25 employed for checking the am- OHMS plifier's frequency characteristics. O COMMON

A.C. METER HIGH RESISTANCE 400 VOLT RANGE ,

R20 C4 R23 C3 L J Z GH. d IC4 = C2 \ - = R24 R22 AUDIO OSCILLATOR

www.americanradiohistory.com 532 RADIO NEWS FOR IVIARCH, 1936

frequency characteristics of the other sources, regardless of their setting. I believe the additional tubes and sockets are less expensive than the constant -impedance type controls otherwise necessary. Any The number of channels and any suitable type tubes can be used. CHARLES M. DIBRELL, MDIO Ardmore, Okla. How to Build a Two -Way Phone System For the "out -of- the -way" places where there are no telephone lines, the simple communication system shown below can be used for establishing a two -way phone WORKSHOP channel over short distances. For the complete channel two outfits are required, one at each end of the line. Regu- lar amateur phone communicating prac- 4 tice is used. A definite time is arranged in Items of interest for beginners, ex- advance for operator Jones to call his radio constructors. 4:4 perimenters and TEAR SFMR TRMIANSKE F M R Conducted by The Associate Editor in alternation. With the disc in Shows current SW4 Simple Stroboscope step, the glow will appear on one plate Rectifier Action only, while if the tube be viewed from a 45V. circumfer- Many forms of motion, too fast for the point 180 degrees around the follow, can be "slowed ence of the disc, the glow will appear on unaided eye to the down" and analyzed with a high -speed the other plate. Still other portions of cycle can be selected by shifting your view- movie camera. In similar fashion you can 3V MIKE use this little gadget to get a slow- motion point. using 866 type rectifiers will rectification process in mer- Amateurs o picture of the the sw2 -vapor tubes, and to find just what find the device useful, because when cury step the angle over which the fraction of the cycle is being used. An disc is in glow is visible indicates how much of the cycle is being used by the tube. For ex- RECEIVE ample, if the filter is of the condenser - input type and the first condenser is too CO large, the glow will be seen through a nar- SW3 row angle only. This indicates that the tube is carrying current in brief spurts of possibly dangerous peak value. Higher audio frequencies can be observed in like SW4= S.P.S.T. SWITCH using discs more holes. SW2,SW3= D.P.D.T. SWITCHES manner by with LEAVE SWITCH.IN "RECEIVE POSITION WHEN Of course, the stroboscope can be used NOT IN USE, THIS WILL DISCONNECT MIKE to study many other forms of high -speed BATTERY. motion, such as motors, alternators, en- gines, etc. friend operator Smith, who listens and C. D. SAVAGE, when Jones is finished calling, both oper- or this kind would ordinarily Portland, Ore. ators throw the switches to the sending investigation of whichever the case may be the use of an oscillograph receiving end, require and then Smith does the talking. The device consists of a heavy cardboard Mixing Panel shaft of a fan motor One of the connecting lines can be a disc mounted on the well insulated or a the guard has been removed. Here is a circuit that fellow- experi- continuous fence wire from which 20 insulated wire. The ground may be eight or more inches in menters might be interested in. It is a No. 18 or The disc for mixing several input sources serves as the other conductor. If the dis- diameter, with two slots about an inch method opposite edges. A such as two microphones and a pick -up, tance of the channel is not too long a bell - square located near could be installed. spool makes a convenient hub without the use of expensive constant - ringing call- arrangement tight- fitting the 2- d.p.d.t. switches to mounting the disc. For speed control, impedance volume controls ordinarily re- Instead of for - the outfit from "send" to "receive" lamp socket and a heavy -duty rheostat quired for each source. Standard 500,000 change a are used in each grid a 4- p.d.t. switch could be used. Another of at least 30 ohms are wired in series with ohm potentiometers circuit and the variation of any one con- suggestion for this switching arrangement the motor (Turn to page 570) Employ a lamp of the right size to bring trol has no noticeable effect on volume or the motor speed to approximately 1800 to find this speed is r.p.m. An easy way .04 rotating disc, a CONTROL to examine, through the MIXERS 56 MFD. neon lamp lighted from the 110 -volt a.c. 56 line. As the speed approaches synchronism (1800 r.p.m.) the glow will flicker slowly, MICROPHONE .4 MEG. shifting from one plate to the other. When .04 the disc is in step the glow will remain on M F D. one plate or the other. Now, with the disc slightly off synchro- an operating mercury -vapor MICROPHONEI nism, examine .4 MEG. tube of the 82 or 83 type. The blue glow MEG will be seen to shift from one plate to the other, showing that the plates carry M FD 56 .4 MEG. PICK- UP B+ 480 V. 10 MFD._ 800 OHMS'

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 533 I Serviceman's STUDY Outputof Meters

THE WESTON MANY THE R. C. A. NEON -TYPE RECTIFIER servicemen do not appreciate -METER TYPE the importance of the output meter OUTPUT METER as an aid to proper receiver alignment. Some of the more experienced, who have NO modern high -grade superhetero- become proficient in adjusting by ear the on hand, will be described next month. dyne receiver can be precisely simpler circuits of former years, continue The neon tube is used as an indicator to apply this aligned by ear. Small differ- method to present -day rein some manufactured instruments. Fig- ences in ceivers. Others have not acquired suf- sound intensity, readily appar- ure 1 shows the circuit employed in the ent with an output meter, are not ficient familiarity with the various meters per- available to employ them effectively. R.C.A. output meter. This apparatus ceptible even to trained listeners. When may be used across a speaker voice coil. only one or two circuits are badly out Since the maximum voltage in this por- of adjustment in a simple receiver, con- By John Strong tion of the circuit is not sufficient to siderable improvement can of course be cause a neon bulb to light, an imped- obtained even without an output meter. able when properly used. Several simple, ance- matching transformer is used to in But more complex sets, when several inexpensive devices are shown in the raise the voltage to the proper level. A circuits require aligning, the unavoid- accompanying photographs. The more bulb of low power consumption is em- able slight inaccuracies which are bound elaborate ones have a wider range of ployed to obtain high sensitivity. Va- to occur in each circuit adjusted by ear adaptability which makes for greater rious ratios are available to adapt it to become cumulative, with the result that speed and convenience in handling a differing output circuit impedances. maximum sensitivity and selectivity are quantity of work. For those who prefer Signal level adjustment is regulated by not obtained. Furthermore, the fidelity to build their own, a simple tube volt- varying R1. of reproduction of some superhetero- meter type, which can be constructed at dynes is largely dependent upon the negligible cost if a spare 1 -ma. meter is "Shadowgraph" Output Meter proper adjustment of the intermediate - Figure 2 shows how Philco has frequency amplifier circuits. Correct adapted alignment PHILCO EMPLOYS the familiar "shadowgraph" of such circuits is impossible THE "SHADOW GRAPH" tuning meter for without proper use as an output meter. equipment and knowl- This instrument is designed edge of the required characteristic. to be used on the primary side of the output trans- Visual Devices former rather than in the secondary circuit. Any A condenser is used to isolate device which will give a visual the steady plate voltage indication of slight from the output changes in signal meter. The higher signal voltage reaching the voltage pres- detector circuit of ent in this portion of the circuit a receiver may be used for alignment is stepped down, rectified and applied to a purposes as an output meter. The va- metal riety of instruments vane type d.c. meter. With no which will do the signal voltage, the vane intercepts job ranges from a light flashlight bulb to a from a battery- cathode -ray oscilloscope. operated pilot bulb, While the causing a dark area to copper -oxide rectifier combined appear on the with a rectangular screen. As increasing sensitive milliammeter as supplied signal with voltage is applied, the vane swings most analyzers is ideal for most pur- cor- respondingly until at maximum it is poses, less expensive apparatus is at suit- right angles to the (Turn to page 555)

R1= 100,000 SW. 1.5 V. 3000 600 300 60 R.F. OHMS 2 MFD. OHMS OHMS OHMS OHMS OR I.F. TUBE T ( 400 V.)\ 4' SERIES HIGH PILOT LIGHT r COND. 45.60 150 T 'i 6 DOFF 1.5 LOW H-- 1.5 OFF O 0 -8 -METAL 6 MA, A VANE 150 60 15 d NEON BULB' 40.4 62.1 341.9 888.9 APPROX. B-F OHMS OHMS OHMS OHMS 3500 I OHMS FIG.1 FIG.2 SCREEN A.V.C. LINE. FIG.3 FIG.4

www.americanradiohistory.com 534 RADIO NEWS FOR MARCH, 1936 The ER DICE Sometimes its just an idea, sometimes making the difference between "red ink" In this issue the Service Editor gives you valuable to you, Conducted by Zeh

CUTTING TUBING STRAIGHT angles to and drives a 6 -volt automobile generator fectly cut -in a plane at right one line will Figure 2. How many times have you at a 3 -1 ratio by means of the conven- the axis of the tube -only used a hacksaw on a cardboard tube tional V- shaped fan belt. Sliding contacts have to be drawn -at the desired distance with "Tower of Pisa" results? on the platform permit it to turn with the from the end. wind. The propeller is offset 31/2 inches When impregnated with wax, such tub- from the turntable pivot, providing a ten-. ing may be efficiently used in oscillator WITH several manufacturers putting coils, wave -traps, etc. and dency to turn away from a strong wind, out Wind -Mill Power Plants Mr. McNeil receivers designed especially for use with the effect of a governor. Kink is good enough to answer letters personally Another Soldering Iron with them (see this month's Service plant. and the in reference to this unique power As long as soldering irons are used, so Prize Contest), both the farmer Canada. rural serviceman are getting a new His address is Atwater, Sask., long will the serviceman devise new ways "break." Some servicemen are jacking McCalla Brothers, of Mercer, Pa., send to heat them and new gadgets to hold by constructing the wind- along the following pointers on windmill them ! up their profits irons (the mill and charging unit themselves. installations: "Having had several soldering "Obviously, as high a position as pos- type with the small diameter, fine point) Windmill Power sible, within reasonable distance from the burn out at the critical moment, I deter- receiver location, should be chosen for the mined to heat them in a modernized ver- Considerable interest was evinced by windmill. The charger should be positioned sion of the good old- fashioned external rural servicemen in the windmill -power - at least 10 feet above the ground, and be method. I clipped off the leads, and system described by Ronald A. McNeil, sure that no obstructions, such as trees, mounted a heater unit, takers from a para- in this department some two years ago. Mr. silos and large buildings, are close enough bolic electric heater, on a Masonite base, McNeil sends us the accompanying photo- to obstruct the wind. In almost every lo- covering it with a guard of wire screening, graph (Figure 1) of his improved power cation there is a prevailing wind, and the as shown in Figure 3. The iron is heated plant. The present model is mounted on tower should be erected in such a spot as by placing the copper inside the heater a standard steel windmill tower. A 6 -foot to take full advantage of it. unit-which will take care of even a large airplane -type propeller is mounted on the soldered iron. A small copper will be overheated if T Ford, "All connections must be well - front -wheel assembly of a Model such as are made to left in the center of the unit. You will excepting, of course, how posts. These latter should be made with quickly learn from experience just soldered lugs. Be sure the ammeter, relay far out to place it to maintain the correct "IT'S AN ILL WIND working temperature, and will certainly THAT BLOWS NOBODY GOOD" and battery connections are tight. In watch out for high- resistance appreciate the freedom from the cord. other words, effective little electric Figure 1. Windmill power has opened contacts. In running the wire from the This unit is really an up a new fount of income for the rural charger to the battery, number 12 furnace, and small bars of steel can be wind heated red hot for tempering, forging and serviceman. B. & S. gauge copper wire can be used on " H. Parker, Los Gatos, distances up to 50 feet. From 50 to 75 other work. -H. feet, number 8 is in order. From 75 to California. The effectiveness of this device as a 200 feet, number 6 or 4 B. & S. must be In cases where the receiver furnace would be increased manyfold if employed. with a refractory draws less current than the average charg- the coil were covered rate, it will be more economical to compound, such as an oxychloride cement. ing magnesium oxide house the battery as close to the windmill Mix two parts of with rather than alongside the set, one part of powdered asbestos (by weight). as possible- of magnesium chloride which, however, is usually the more con- Dissolve one pound location. (Many farmers, though in a pint of water. Use this solution to venient the consis- in the habit of milking at 4 a.m., balk at mix up a thick paste -about through sub -zero snow tency of mud pies. Apply this to the out- the idea of trudging after first wrapping it in to put electrolyte in the battery !) " side of the unit, at least six thicknesses of asbestos paper. THE DAY'S WORK Moisten the asbestos paper before applying the cement so that it will not absorb mois- A couple of kinks with which to start, ture from the mixture. Build up a pro- and, perhaps, save the day: Frank W. tective wall three to four inches thick. Bentley, Jr., of Missouri Valley, Iowa, This cement will harden in about 12 hours, sends us the idea illustrated in the photo- but the unit should not be used for several graph of Figure 2. Every serviceman has days. repeated occasion to cut cardboard tubing The protective material will practically to a desired length -the problem always eliminate loss of heat by radiation, allowing being to cut the ends in parallel planes The illustration is almost self -explanatory of how this can be accomplished easily and quickly. Take an envelope, the longer the better, and wrap it tightly around the iiiiiiiiiiiii

. i:u ari,r,asmmnono tubing so that the edges coincide where Ic-=_° rr;ryniiimmorps.iimis! they overlap. Mark this edge, with a .. MEE It MUM= pencil, clear around the tubing. Then MEW. MMMMMi move the envelope away from the mark NMI:_r:.. MEW NMI the length of the desired tube and rule - another circle. The pencil lines form per- I ! fect guides for the knife or razor blade. FIG.3 Obviously, if one end of the tube is per-

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 535

Cathode -Ray Oscilloscope Contest pp ADIO NEWS is offering monthly prizes of T3ENCH $10.00, $5.00, $4.00, $3.00 and $2.00 for new and novel uses the its of Cathode -Ray Oscilloscope the smaller things that count, in in radio servicing. What our readers want to and "black," in the serviceman's ledger. know is how the oscilloscope is now helping servicemen make more money, by -1. Reducing the both ideas and kinks that may time prove necessary for specific service jobs, and - immediately! 2. Increased effectiveness and customer satisfaction. New, associated oscilloscopic circuits and apparatus may well contribute to this end, and Bouck, Service Editor are therefore good contest material. Photographs of servicemen at work with the oscilloscope will much higher temperatures to be attained. add merit of prize- winning caliber, as will oscil- The oven now should be used with a lographs (drawings made from observations rheostat for temperature control-or, bet- ( Tell on the oscilloscope) and ter yet, a transformer. As a matter of fact, oscillograms (actual photographs we'd suggest the use of the rheostat or of the images on the screen). These last are easily transformer even with the open unit, as Us Your taken with any good camera, with panchromatic considerable economy of operation will re- film or plates. Address contributions to, yours sult, and, with the temperature adjusted for better servicing correctly, the iron can be placed completely - in the unit at all times. Full voltage Problems The Service Contest Editor should be used to bring the unit up to the desired temperature, after which it should be dropped until the temperature is maintained. The oven -with the refractory covering -will be much more eco- CRYSTAL nomical to operate than the open heater, 20 III MMFD. and the transformer always more so than t7 w Ç3 the rheostat. 955 60 OHMS Neon Lamp Condenser Tester U 11 CRYSTAL f Like soldering iron kinks, these devices cl seem to be legion. Every once in a while 300 one comes through that is a little different MMFD. O C2 -and it pops up in the Service Bench. Oscillator Marion Wade, of the Lyon Maytag Com- fò pany, Leavenworth, Kansas, sends us the By TI MFNLL circuit shown in Figure 4, which he uses F. Siemens MP' O Ñ for testing condensers, resistors and 59ÓO grounds. a result of the increasing popularity OHMS L3 "By using the one test lead on the hot of all -wave receivers, there has been s

A I side of the line, the light will glow on both an insistent demand for a low- priced l LO HI Y ;.- -4-1.4, _,..1 400 1(0. KC. sides of the plate to show a ground. By instrument to enable their more accurate 1000 510-420V. 1,',.__ g0 V. FOR 0.0 ONLY adjusting the resistor so that only a very calibration over a wide frequency range. 50-60'. REMOVE UNK The new R.C.A. small portion of the lamp is glowing, it crystal oscillator, which FIG. 4 will give an accurate test every time on a has just been announced, is designed to condenser or resistor." provide a degree of accuracy and range of ratories and amateurs it is indispensable. We don't quite see the necessity for the application far beyond that obtained by For other means. experimenters and DX fans it will shunt resistor across the filament, and Mr. This new instrument utilizes prove a welcome a 955 acorn and long- sought -for aid Wade gives no value for it. The inter- type tube as an oscillator. It to greater radio enjoyment. ested reader is referred to the following is crystal -controlled to an accuracy of 2 1935 issues of RADIO NEWS for further de- parts in one million. It is difficult to con- tails regarding neon lamp test arrange- ceive such a degree of precision. We might ments- January, April and August. compare this to a watch so marvelously constructed that it would not lose or gain Replacing a Dial Bulb more than one second in six days. Two fundamental test frequencies are Mr. H. Sparks, whose name is as well supplied, suited 100 and 1000 kc., plus or minus to radio as it is to residence in .05 of one percent. Loveland, Ohio, Since the output is sends along the following: rich in harmonics, calibration points "Here's a time saver in replacing the may dial be obtained from 100 to 20,000 kc. in 100 bulb in a Majestic Model 50. Remove the kc. steps and metal dial 1000 to 50,000 kc. in 1000 escutcheon which is held with kc. steps. In addition, individual (Turn to page 553) calibration of the crystal used is supplied with each instrument, with the temperature at 0 -25 000 which the calibration is made and the OHlv15 NEON correction factor necessary to obtain the LAMP extreme precision of 2 parts in a million. The schematic circuit is shown in Figure 1 1. As shown, the instrument operates I from 115. V the usual 110 -120 volt, 50 -60 cycle line supply and normally supplies a 60 -cycle modulated signal. An unmodulated signal may be obtained by using a 90 -135 volt 2s battery supply. WATT The apparatus as illustrated is very corn- pact and simple in I I operation. Complete instructions for its use are furnished with FI G.4 each TEST instrument. Its use provides service- PRODS men, for the first time, with a low -cost test instrument of highest precision. For labo-

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936

ACROSS MAI N INCOMING LINE

FI G.3

approaching traffic light problems. Simply by cutting this analyzer into the circuit eliminating and then applying various filter banks by turning the dial you are. enabled to find, in short order, the exact filter combination to produce best results. Traffic Signal Noise After the correct filter combination has been determined these units can be installed directly in the signal box if there By J. R. Steen is room or in a metal container fastened outside of the box. The traffic light main- RADIO interference from traffic sig- by the method of "cut and try." However, tenance crew will often dig up a con- cause of disturb- if the serviceman has the filter parts shown tainer and attach it to the signal box for nais is a common weather- home and automobile radio in each of the three diagrams he will be you. Westinghouse makes a good ance on both proof marine box which is ideal for the receivers. Generally, however, nothing well equipped to go out and show real largely because people results. In my own work along these lines, purpose. is done about it radio, close to the control box, is bothered with this type of inter- I have dispensed with the "cut and try" A car who are job ; by know where it method in favor of the Sprague interfer- a great help while working on the ference either do not the radio you can tell at once they do, they assume ence analyzer. This is the last word in noise listening to comes from, or, if valuable in ordi- when you have hit upon the proper filter be eliminated. elimination work -one as that it cannot nary home interference jobs as it is when combination to eliminate the interference. EVEN servicemen have hesitated to ap- approach the problem for lack of a after this tube. After measuring the voltage across re- definite plan for going 20 -Watt Amplifier sistors, R11 and R17 with a vacuum tube volt- business. meter, to be sure that they were equal, the de- personal experience as a ser- flecting plates were connected so that one side My own (Continued from page 531) of the signal sweeps horizontally, the other ver- viceman has convinced me that there is a tically. The resultant trace must be a straight profitable and logical field in eliminating line and at 45 degrees to the axis-nearly, be- and the output signal to the other set of deflect- are not equally sensi- signal interference for the fellows who ing plates. When proper phase relations exist, cause the two sets of plates should be a line. If it curves tive. The experiment proved that this was the will go after it. Just as they did in my the trace straight case. Reversing the connections to the input glad to at the ends, third harmonic distortion is present. the trace. town, many city officials will be While there was a slight curvature at the ends grids of the 6C6's did not change go to the trouble of ex- the line was perfectly straight at This was a proof that the inverter delivers a cooperate if you at full output, symmetrical signal to the push -pull circuit. the matter carefully and even slightly reduced levels. Another cathode-ray test plaining made to establish the action of the inverter (Continued on next page) demonstrating how much radio interference was an innocent -looking traffic light can actually cause. With the number of lights now used in the average town or city, I hardly slice of have to point out what a juicy ..,...--/ i.." 18 I' 'á 'S business can be had if you get the job of l eliminating interference from them. I' traffic -light inter- 2 DIA. Complaints regarding GROMMET ALL HOLES NOT OTHERWISE SPECIFIED TO BE .N0.27 DRILL FI G.2 ference should be made to the local police HOLE public -works commissioner, A commissioner, S HOLES -+ TI - t DRILL DRILL t is 14? ,_ 7/6 DIA. 4 HOLES CI--I ¡n1ó city electrician or contractor -whoever r12 S/{6DRLL_ _ _L__ in charge according to your local set -up. 1 This information can easily be obtained at city headquarters. The yellow caution light or blinker \ _ LN IO H-' RI is the worst offender. (flasher) usually GUT -1a Such lights are generally installed at minor OUT a traffic intersections in residential districts d\ radio receivers are in use. The P`DRILL ,®, where many 4 HOLES red and green lights operating at regular 10 _ __ _ 36DRILL do not cause such {z---,- or 30 second intervals 6 _ :. - really serious interference. k-I 6-s+ 2{.., t of contactor. SOCKET / Figure 1 shows one type :í I / LN .; ,®` disc operated by a ® gh D is a saw -toothed .13/..E.' DIA small motor. A represents the contacts in series with the flasher lights. Choke L con- r 16 a pound roll of T2 3 sists of approximately / > 216 No. 18 bell wire (up to a 5 amp. circuit), wound on a core of about 1/ inch S- , CONTROL I lot , K-276 - . .. =1`= diameter. Condensers C are from 1 to 1.5 gh _ OUT j17 7

OUT i mfd. 220 volt AC ratings. V MI - DIA. r.-Im 1 ,I More obstinate cases of traffic -light interference will require the filter shown in LJ 1-t--11 irt-i SW2 h' 3 ',0 d- iii 2. If interference still persists after l T r Figure

VOLUME VOLUME 7 l, . circuit of Figure DIIA { 6/ { a filter, add 1' using such I < 22 > CONTROL CONTROL "IaD 4 3. The combination of either circuits 1 -3 I DRILL S HOLES 6 DIA. --8 I. 7. radio noises from this , 3?- T or 2 -3 will eliminate CUT OUT A -rá e 4 S' 'M O I 9 l. source in just about every case. The values t < pSW1 .}m CUT OUT 2 & 3 I of condensers and chokes in Figures I m O 3g a4a,-i2 2 I` are the same as those for Figure 1. -{'4 2-i \ j" . . _/,I4mr ___± As is well known, much of this interference elimination work is experimental 17 up to a certain point. It means working

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 537

Three New METAL 25Z6 CATHODE NO.2 TUBES PLATE PLATE NO.A NO.2 By Richard Purinton ® ©

TYPE 25A6 - HEATER Power Amplifier Pentode Voltage 25.0 volts Current 0.3 ampere Maximum overall length 3%" Maximum Diameter 1 5/16" Base Small Octal 7 -pin HEATEOR oSHELL Class A Amplifier, Operating Conditions ° and Characteristics CATHODE© -KEY Heater 25 .0 25.0 25 .0 volts NO.A Plate 95 135 180 max.vlts. THREE new Screen metal tubes have been 95 135 135 volts A. C. Voltage per Plate 125 V. Max. announced which Grid -15 -20 -20 volts complete the series Amplification D. C. Load Current as Voltage Factor 90 99 96 Doubler 85 M.A. Max. of tubes for a.c. -d.c. receivers and Plate Rests. 45000 42000 40000 ohms provide a rectifier D. C. Load Current as Rectifier 85 M.A. Max. for automobile receivers. Mutual Cond. 2000 2350 2400 umhos. Peak Plate Current 500 M.A.per plate These tubes, manufactured by Raytheon, Plate Current 20 39 40 M.A. Screen Current 4 8.5 8.0 M.A. are: the 25A6, an output power- pentode Load Res. 4500 4000 5000 Ohms 6X5 similar to type 43 ; the 25Z6, a full -wave P.O. 0.9 2.0 2.75 watts high- vacuum rectifier and voltage doubler Dist. 11% 9% 10% Full -Wave Rectifier (Heater Type) similar to type 25Z5; Heater and the 6X5, a full - Voltage 6.3 volts wave rectifier for automobile use. Char- 25Z6 Current 0.6 ampere acteristics and socket layouts of the three Rectifier Doubler Maximum Over-all Length 3%" tubes are shown below. All three Maximum Over-all Diameter 1 5/16" tubes Heater: Base Small Octal 6 -Pin have the same dimensions and are mounted Voltage 25.0 volts A. C. Voltage per Plate 350 volts max. a Current 0.3 ampere Peak Inverse Voltage 1250 volts max. in steel shell of the same size as that of Maximum over-all length the 6F6. 3%" D. C. Load Current 75 M.A. max. Maximum Diameter 1 5/16" Peak Plate Current 375 M.A. max.

R7, R8 -IRC carbon resistor, 25,000 ohms, 2 grid clips 20 -Watt Amplifier watt 2 6B5 tubes Triad or Sylvania R13 -IRC carbon resistor, 1500 ohms, 1 watt 2 6C6 R14, R15 (Continued from previous page) -IRC carbon resistor, % meg., 1 watt 1 5Z3 R18- -IRC wire wound resistor, 150 ohms, 10 1 76 watts 1 6A6 R20 -IRC carbon resistor, 1 meg., 1 watt Parts List R21- Electrad Truvolt resistor, 50,000 ohms, 25 watts Cl- Cornell -Dubilier PE-B6808 paper filter con- R22- Electrad Truvolt resistor, 25,000 ohms, 50 denser, replacement for 8 mfd. 800 volts peak watts C2 -Two, Cornell -Dubilier EBSS00 dual elec- R23 carbon -IRC resistor, 75,000 ohms, 1 watt 5 Meter Car Radio trolytic condensers 8 -8 mfd. each, 525 peak R24- Trutest, center -tapped resistor, 20 ohms C3- Cornell -Dubilier electrolytic condenser 25 SWI -SPST toggle switch mfd. 50 volts SW2 -SPDT toggle switch (Continued from page 520) C4. C10, Cll, C12, C14, C15, C17- Cornell- Tl- Amertran Power transformer, type 13981, Dubilier tubular paper condenser, .1 mfd., 400 primary, 115 volts; secondaries, 425 -0 -425 Next month this receiver and its v. type DT -4P1 volts, 160 ma.; 5 volt, 3A; 2.A circuit and con- volts, 5A; struction will be described for the benefit C5, C6- Cornell -Dubilier dual electrolytic con- 2% volts, 10A; 2/ volts CT, 5 -A. of denser 8 -8 mfd., 525 volt peak those readers who would like to build a complete T2- Amertran output transformer, type J874, installation. C7, C13, C16- Cornell- Dubilier electrolytic con- primary 10,000 ohms CT, secondaries, 500 denser 25 mfd., 25 v. ED -2250 ohms and Mr. Landry has made many trips up into universal voice coil Connecticut and down through C8- Cornell -Dubilier tubular paper condenser 1 4 -prong wafer New York and socket Jersey and even as far as type DT -4P1, .1 400 volt 1 5 -prong Washington using this wafer socket rig. He has made C9- Cornell -Dubilier electrolytic condenser 8 -8 1 7 -prong many friends among the large wafer socket amateurs he has mfd., 525 volts peak 4 6 -prong wafer socket contacted, visiting their hones and seeing their transmitting and Ch- Amertran filter choke, Z -913, dual sections 1 chassis 17x11x3 with bottom cover receiving ap- in parallel, 8 henries, 200 ma. paratus. On his last trip to Washington he 2 terminal strips, 6 terminals each contacted R1, R2, R10- Electrad potentiometers, 500,000 2 tube shields W3BAI, at Boling Field, from a dis- ohms tance of 16 miles and got specific road informa- 3 V. C. pointer knobs tion from R3 --TRC carbon resistor, 1250 1 the operator to bring him direct to ohms, watt 2 indicator dials marked "Volume" that station. R4 resistor, 1 He also worked W3DBC and -IRC carbon 50,000 ohms, watt 1 indicator dial marked "Tone" number a R5, R9, R19 -IRC carbon resistor, 100,000 ohms, 4 terminal lug strips -2 terminals of other amateurs en route. On his I watt Connecticut trip he contacted WIEER of Noroton 1 line cord and plug Heights and R6, R11, R12, R16, R17 carbon resistor, 1 visited this outstanding 5 -meter sta- -IRC rubber grommet tion. Everywhere .5 meg., % watt 1 binding post in his travels great interest has been shown in his tiny 5 -meter car -radio.

www.americanradiohistory.com 538 RADIO NEWS FOR MARCH, 1936 Theory and Practice for Correct IMPEDANCE MATCH

SIMPLIFIED EQUIVALENT CIRCUIT By C. A. Johnson OF AN AUDIO TRANSFORMER. FIG.1 Part Six

There is a further loss between pri- Za = internal impedance of source. IN Part V, we described a method of mary and secondary due to flux leakage Lp = Primary inductance. measuring the frequency response of between the two. A part of the primary LL = Leakage inductance. an audio transformer. This is a direct flux, for example, generates no power in Ca = Distributed and mutual capacity means of determining how well a given the secondary load, because it does not lumped together. between transformer will effect a match However, it Zb Load impedance. impedance. Care- link with the secondary. = two specific values of as The ratio of the transformer shown ful measurement, under operating con- still appears in the primary circuit ditions, should always be employed to a parasitic inductance. The inductive in Figure 1 is unity. Any other ratio, confirm (or dis- prove) theoretical per- reactance produced in the circuit from N, may be reduced to unity ratio by formance. On the other hand, a large this effect is called "leakage" reactance. dividing all impedances in the secon- amount of unnecessary measurement can The same analysis applies to the sec- dary circuit by N2. Note that this pro- be avoided; if it is preceded by intelli- ondary and its associated circuit. The cedure follows logically from the basic gent circuit analysis. In this installment, total leakage reactance is divided be- fact that the ratio of a transformer we will try to point out some of the two circuits in proportion to merely acts a a multiplier. (Formula an an- tween the factors to be considered in such the turns ratio. 4, Part IV.) alysis of an audio transformer. Such a discussion, at this point, must necessarily Any inherent resistance in either wind- Frequency Response be general. Some of the more important ing dissipates energy in the form of I2R exceptions will be discussed in detail losses. In a well- designed transformer Now, let us see how this network later. the winding resistance is relatively affects the transfer of power from Za to small. Hence, it can usually be disre- Zb. We can tell by inspection that Lp THE ideal transformer (described garded in a circuit analysis that is de- will have the greatest shunting effect at in Part IV) neither stores nor voted to studies of frequency response. low frequencies. Similarly, LL will pre- dissipates energy within itself. The various distributed capacities in sent the greatest series reactance at the Any physical transformer does both to a physical transformer may either pro- highest frequencies. The same is true a certain extent, depending upon condi- duce resonance (or by -pass the signal). for the shunting effect of Ca. The tions. If it didn't, it would obviously Both of these effects will obviously vary question as to which is the more im- have zero insertion loss, and would have with frequency. portant depends upon their relative a uniform response for all frequencies. magnitudes. Our problem, then, is to discover what The Equivalent Network For studies in the low- frequency re- causes this storage and dissipation of The exact equivalent circuit of an gion, we may limit our equivalent cir- energy, and how it varies with fre- audio -frequency transformer is a rather cuit to the effects Lp as shown in Fig- quency. complicated network. In such a circuit, ure 2. The transmission loss in deci- Limitations in Design elements of resistance, inductance and bels for this circuit is given by For- capacity are used to represent effects mula (1). These causes may be subdivided in The similar to those described above. Decibels loss due only great detail, but all are a result of one of such a transmission characteristic to shunting effect of LP or more of the following fundamental circuit can be calculated, exactly, for limitations : 2 any frequency. However, the process Z, Zb 1. The inductance of a winding cannot is long and tedious and we often do 10 log 1(1) not be made infinitely large. have sufficiently accurate data on all r1+ ( (Za + Zb)coLp ) 2. All of the magnetic energy gen- of the transformer constants. In prac- erated by the primary is not reproduced tice, we can simplify the problem by Now if the primary inductance is in the secondary. using approximate networks. These con- known for a given transformer, the loss 3. Each winding has resistance and tain only the elements of importance for due to its shunting effect may be calcu- distributed self- capacity. the particular problem under considera- lated for various frequencies. Suppose 4. There is a mutual capacity be- tion. we have given a transformer with the tween the windings. Three of the most important effects following constants: We have already pointed out (Part generally encountered in audio -frequency Lp = .5 henry. V) that limited primary inductance transformers are illustrated in Figure 1. Impedance ratio = 200 ohms to 200 causes the primary to act as a shunt The symbols used have the following ohms. across the source, at low frequencies. meaning: How far will this transformer be This fact indicates the desirability of e = e.m.f. generated by source. "down" at 30 cycles? (Turn to page 566) making the primary inductance very high. However, there is a definite upper limit, particularly in the case of a step - up transformer. Whatever the value of OOOOO Lp, L. must be equal to N'Lp. (See Formula 4, Part IV; N = turns ratio.) The physical limitations to the size of zb L8, therefore, automatically fix the size of Lp. A part of the primary energy is consumed in magnetizing the core, and in losses due to eddy currents and hystere- EQUIVALENT CIRCUIT FOR EQUIVALENT CIRCUIT EQUIVALENT CIRCUIT FOR materials in use to- SHUNTING EFFECT OF Lp FOR LOSS PRODUCED SHUNTING EFFECT OF Cd sis. With the core BY LL day, this is a relatively small loss, ex- FI G.2 FI G.3 FI G.4 cept in the case of output transformers.

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 539

eAnalysis and Test Report on 24 -TUBE All -Wave Super

By L. M. Cockaday and S. G. Taylor

ANEW 24 -tube receiver just placed ception and execu- on the market and submitted to tion- getting away the Radio News Laboratory for from the conven- test is extremely interesting in itself be- tional form to a de- cause of the numerbus refinements and cided degree. modern developments incorporated in Outstanding its circuits. Beyond this, it is interest- among the features ing as an expression of confidence, on offered in this re- the part of the manufacturer, that pros- ceiver are its real beauty of musical are necessary and what they perity is returning sufficiently to warrant are used reproduction, its wide tuning range for. This can be answered by follow- the production of a laboratory -built re- (from 4% meters to 2400 meters di- ing the action of the receiver beginning ceiver which is built to an ideal, with- vided into six ranges) and the com- at the antenna and ending up at the out regard for price limitation. Actually. bination of simplicity and flexibility in loudspeakers. for a custom -built receiver the price is operation. not particularly high but it is, of course, The complete chassis has been re- The Circuit high enough to carry this receiver out ceived at the Radio News Lab. for "on of The first tube is a 6K7 radio -fre- the "garden variety" of commercial the air" tests. While sufficient time has production receivers. quency amplifier. One tuned radio - not elapsed to permit completion of the frequency stage is employed on all five Hi- Fidelity tests, results during the preliminaries wave -bands utilizing this 6K7 tube Featured have been extremely satisfactory. Next which is approximately equivalent to The receiver, as illustrated on this month a report on the completed tests the 6D6. The first detector is also a page, is the new "Royale" model, pro- will be given. In the meantime the fol- 6K7 and the oscillator duced by Royale Radio circuit employs Crafters, a sub- lowing description of the circuit (shown a 6C5 triode. The intermediate-fre sidiary of Midwest. It consists - of three below) will be of interest to many tech- quency amplifier consists of units 13 -tube chassis, two stages, -the an 11 -tube nical- minded readers. again with 6K7 tubes and power supply and power amplifier, working into and The "Royale" employs 24 tubes which a 6H6 second detector. The a speaker assembly which incorporates inter- can be either metal tubes or a glass mediate- frequency amplifier employs three speakers. Three different con- equivalent, the so- called "G" tubes, the triple -tuned transformers with a variable soles are available to house the equip- choice being left to the purchaser. The resistance in one circuit of each. The ment, each of which is unusual in con- average reader will wonder why 24 tubes two variable (Turn to page 567).

00? .05 AMER. 2500 I.F.=465 KR. °i,w FD IW. OHMS M2FD i00^MMFD._. 4o0v. 4000. IOOdMMFO , 100MN1FD. ! 50,000 4iW 10 .05 ICA. ' ICA ' MICA.. `,', OHMS 1 MFO. MFD. HEAD PHONES 365 ISTDET¡ 50 50 I F. F,O W TRIMMLCRO(T) IsT So ' 2501 F r 50 `,255.05ri MINED. I \ DRYISTA_F. 6K7/ MMFD. MMF'D', 6K7 MMFO .m FD MMFD 6K7 I ' 6H6 6C5 5002,0100 M UFO , ';- ; 6C s 1T l 50,000 TTToT 9Mis

13P. i3Os os 4W

0)I YELLOW 05 Y! ÓHMS ÑF3 .05' 50.000 WHITE CONTROEL 25w. TENUATOI O V. Ìw5 GREEN .O5 G. ' PHONO RED 25 OHMS ' 25000 W. 900 W H TUNING. MMFD. qVC V 00 50 óV OMS B+ FD. --TONE \ MICA AMP. A.VC. CONTROL`, 6K7 6H6 ICA : TU ALITE `400 MMFD vD. e7c5 6C5 MICA. s+ i T aoo OHMS so,olD ON CALL 05,0.c. OH MS LETTER LIGHT M No. I W. DIAL LIGHTS MICA 6J7 e 700,000 FD OHMS a+0U 500.000 1W. oso. oHms 6C5 WHITE ii%s ?4350CNMáOÖV. T' GREEN IYl. B+ YELLOW :SON'ON. B+ 0,742.,t .OS HiS0 M. FD. '200,000 RED 4OOV C.SWITCH ÁOÓV. LY. OÌtr ÓÑ MICRO- 11 BROWN ,0 5 MFD TENVATOR -ír .36 2000MMFD .G 4D ;Y. mmr5 o BLACK MICA. áOÓÙ. 120 -l 500 !Z 011$MOD 6 -6F6'S 50,000 .25W 2 -DRIV6F6'S .5wHM0 o25i.5 .00,000 olITPGT ER t8

ALL UNITS WITHIN DASHER BORDER RE MOUNTED 154 MFG." ON THE POWER CHASSIS. I WET.

L ON I'

www.americanradiohistory.com 1936 540 RADIO NEWS FOR MARCH,

AN UNUSUAL RADIO SET -UP 11 radio table, designed by the editor of this department and installed in his city apartment. It will accommodate three or more receivers at one tine, and will have connections to three different antenna systems. The baffle is faced with a reddish -gold silk screen in a natural ma- hogany frame, to break the severity of the large baffle surface and conceal the speakers.

15 2:30 -4 1050 CX26 Uruguay 2 NNRC 2:30 -4 1050 CX26 Uruguay 2 IDA 5 -6 1370 WMFO Ala. .1 NNRC 7 -8 1210 WSBC Ill. .1 NNRC 16 1 -1:30 600 WICC Ct. .5 CDXR 1 -2 1300 WHAZ N. Y. .5 UDXC 2 -3 1370 WPFB Miss. .1 NNRC 3 -4 620 KGW Oregon 1 CDXR 3:30 -4:30 1370 KFRO Texas .1 CDXR 4 -5 630 WGBF Ind. .5 CDXR 4-5 1010 CHML Ont. .05 CDXR 4-6 1310 WTRC Ind. .1 CDXR 18 1 -4 940 WDAY N. D. 1 19 2 :01 1210 KIUL Kansas .1 2:30-3 1370 WHBQ Tenn. .1 CDXR 3 -4 1420 WAZL Pa. .1 NRC 3 -6 1500 WOPI Tenn. 1 CDXR 20 2 -3 830 WRUF Florida 5 CDXR k THE DX CORNER GCDXR S. GORDON TAYLOR (For Broadcast Waves) Official RADIO NEWS Broad- cast Band Listening Post Observers appearing else- 3 3 -4 1440 XEFI Chih. Mex. .25 CDXR THE list of Observers 5 on 570 WSYR N. Y. .25 URDXC where in this department includes 5 2-2:30 1310 WEBR N. Y. .1 CDXR United States 1936 appli- 3-5:10 1400 WIRE Ind. .5 R. News the names of all those whose Kalmbach been approved to date. A Alabama: Ray Wood cations have 7 2-3 1290 KDYL Utah 1 CDXR James Halsey on hand .1 R. News Arkansas: number of applications are s 4:40 -5 1420 KCMC Ark. California: Frank D. Andrews, Roy awaiting action. As soon as they have Halsey Covert, Bill Ellis, Henry Evansmith, 5-6 1130 WOV N. Y. 1 CDXR B. McMen- acted upon they will be NNRC Randolph Hunt, Walter been favorably 5-6 1370 WMFO Ala. .1 amy, Radio Fellowship, Warren E. added to the list of Official Observers 7 -8 1210 WSBC Ill. .1 NNRC Winkley were an Observer in 9 1 -2 1250 CMKC Cuba .15 UDXC Fred Burleigh, James A. for 1936. If you Calif. .1 R. News Connecticut: 1 -2 1420 KGGC Joseph 1935 and have not sent in your applica- Covert Dunigan, Stanley Grabowski, J. Mazel reappointment, now is the time 2:30 -4:30 1320 KID Idaho .25 NNRC tion for CDXR Illinois: Herbert H. Diedrich, H. E. it. Applications will also be wel- 3:01 -3:30 630 CKOV B. C. .1 Rebensdorf, D. Floyd Smith, Donald to do 3 -4 1370 KFRO Texas .1 NNRC who desire ap- 1 C. Truax come from other readers 3-5 830 WEEU Pa. All Clubs T. R. 1450 CFCT B. C. .075 CDXR Kansas: Dudley Atkins III, pointment. In making such application, 3-5 Grosvenor, Vernon Rimer of the re- 4-4:30 630 CKOV B. C. °i T. Golson, Aubrey please include a description 4-6 1310 WTRC Ind. .1 R. News Louisiana: Wilbur you are using and Smith V. Deterly ceiving equipment Floyd L. Ham- ac- 10 2 1420 WJBO La. .1 R. News Maine: Danford Adams, also a brief summary of your DX -2:20 mond, Roger Williams to date. Golsen L. Bauer, Louis J. complishments 11 2 -2:20 1370 WSVS N. Y. .05 R. News Maryland: William Kalmbach McVey, William Rank, Frank Zelinka NNRC Massachusetts: William W. Beal Jr., F.C.C. Monitor Schedule 3 -4 1370 KRE Calif. .1 Russell Foss, Warren have been en- 12 2:01 1210 KIUL Kansas .1 Walter C. Birch, The monthly frequency checks C. Reichardt, Evan B. Roberts tirely changed with the result that hereafter 2:30 -3 1370 WIIBQ Tenn. .1 NNRC Mich. .5 CDXR Missouri: M. F. Meade these checks will take place during the second 6-6:30 1270 WOOD Biss, F. John- first week. 13 2 -5 1320 CMOX Cuba .25 Minnesota: Floyd Walter week of each month instead of the son Also the days and hours have undergone a whole- Montana: R. W. Schofield sale shift. Unfortunately the new schedule here A PENNSYLVANIA DX'ER Nebraska: Bud Crawford reached RADIO NEWS too late to be included New Jersey: Robert F. Gaiser, Morton this month but an effort will be made to include Brus, No. Braddock, Pa., has issue. Stanley Meehan it in full in the next set out to collect veri's from every New York: Jacob Altner, Murray Buite- tuber, 1935 kant, Ray Geller, John C. Kalmbach DX CALENDAR state with his Midwest 10- Jr., Harry E. Kentzel, Maynard J. Below are given lists of special and periodic model, and now lacks only four states. Lonis, Harold Mendier, Robert C. DX broadcasts which are scheduled up to March Schmarder, R. H. Tomlinson, William fifteenth. The initials following an item indi- Wheatley cate the organization to which the program is North Dakota: O. Ingmar Oleson dedicated and where a RADIO NEWS special has Ohio: Stan Elcheshen, Donald W. been arranged for by an Observer, his name is Shields given in the schedule. Oregon: David Hunter Don't fail to tune in the RADIO NEWS specials Pennsylvania: Robert W. Botzum, Rob- on this list and as many others as possible -and ert H. Cleaver, Harry M. Gordon, above all, don't fail to report to each station Edward Kocsan, Francis Schmidt, tuned in, giving them as much information as Joseph Stokes, Paul V. Trice you can concerning their signal strength, fading, Rhode Island: Spencer E. Lawton quality, etc. Practically all of these stations South Dakota : Mrs. A. C. Johnson verify reports and where verifications are de- Texas: Isaac L. Davis, E. L. Kimimms it is always desirable to enclose return Vermont : Henry T. Tyndall Jr. sired Virginia: A. J. Parfitt, C. C. Wilson postage. If a large number of RADIO NEWS Drain readers send reports to the stations who dedi- West Virginia: Clifford cate programs to us, these stations will feel well repaid for the time and effort required to put Foreign on these early morning programs. Hours shown are Eastern Standard Time and Alaska: S. A. Tucker are all a.m. unless otherwise indicated. Australia: Albert E. Faull, Aubrey R. Jurd Canada : Bernard J. Clancy, John W. SPECIALS Ker, Ernest W. Law, Philip H. Robin- Day Hour Kc. Call State Kw. Club son February England: R. T. Coales, F. R. Crowder, 5 CDXR Charles E. Pellatt 1 3 -4 640 WOI Iowa Japan: A. T. Yamamoto 3-4 1200 CRAB Sask. .1 CDXR New Zealand: Alexander N. Chalmers, 4:30 -5:30 1200 CKNX Ont. .05 CDXR NNRC L. W. Mathie, Eric W. Watson 5-6 1370 WMFO Ala. .1 Philippine Islands: George Illenberger 7-8 1210 WSBC Ill. .1 NNRC NNRC Puerto Rico: Ralph Justo Prats 2 2 -3 1300 CJLS N. S. .1 Switzerland: Dr. Max Hausdorff 2 -4 1200 CHAB Sask. .1 NNRC 3 -4 1120 CESO N. B. .5 NRC Turkey: A. K. Önder 3 -4 1150 XEFL Tijuana .25 URDX C 4 -4:30 630 CKOV B. C. .1

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 541

DETAILS OF THE TABLE The 5% -foot baffle, rolled out to show the provision for four speakers and the power -pack shelves under the table. The baffle, made of heavily reinforced 1 %- inch lumber, aids materially in obtaining fine quality of reproduction. The general design of the whole table unit is such as to permit the utmost flexibility of installation and operation of receivers f or "on the air" tests.

3-4 1160 CMHJ Cuba .1 UDXC 22 3-4 1220 KYA Calif. 1 CDXR 3:30-4 1310 WEXL Mich. .05 NRC 4-5 620 WHJB Pa. .25 CDXR 5-6 1370 WMFO Ala. .1 NNRC 7-8 1210 WSBC III. .1 NNRC 23 12:01-3 1420 WPAR W. Va. .1 CDXR 2-3 1270 CMKC Cuba .15 NRC 2-3 1040 CP4 Bolivia 10 NNRC 3:01-3:30 630 CKOV B. C. .1 CDXR 3-4 1150 XEFL Calif. .5 R. News Johnson 3:30 -4 630 CKOV B. C. .1 R. News Gordon 4-4:30 630 CKOV B. C. .1 25 2:30 -4 1200 KADA Okla. .1 26 2:01 1210 KIUL Kansas .1 2-3 1370 WOC Iowa .1 NNRC Sundays heard each month. In doing so it will facilitate 3 -4 1530 W1XBS Conn. 1 NRC & - CDXR 12:30 -12:45 a.m. 1420 kc., KGGC, San Francisco, Calif., 1.kw. matters if stations are reported in the form of (Radio 6 -6:30 1270 WOOD Mich. .5 CDXR News) (tips) a list with the frequency, call, location and hour 27 5:30 -6 1310 WRAW Pa. .1 GCDXC 12:45 -1 a.m. 640 kc., KFI, Los Angeles, Calif., 50 [your own local time] when best heard.) 29 2 on 1430 WHP Pa. .5 CDXR kw. (tips) 12:45 -1 a.m. 1250 kc., Minneapolis., Minn., 2:30-3:30 1450 WTFI Ga. .5 CDXR WTCN, Kc. Call 1 2 3 4 5 6 1 kw. (tips) 5 -6 1370 WMFO Ala. .1 NNRC 546 HAL 7 -8 1210 WSBC III. .1 NNRC 12:45 -1 a.m. 1400 kc., WIRE, Indianapolis, Ind. .5 kw. (tips) 556 Beromunster 12:45 -1 a.m. 1470 kc., WLAC, Nashville, Tenn., 565 Athlone 2 March 5 kw. (tips) 570 2YA 1-5 a.m. 1210 kc., TGW, 574 Stuttgart 7 1 2-3 1310 CJLS N. S. .1 NNRC Guatemala, Gua., 10 kw. 580 3WV 5 3:01-3:30 630 CKOV B. C. .1 CDXR 583 Grenoble PTT 3 3-4 1150 XEFL Tijuana .25 URDXC 2 a.m. 730 kc., CJCA, Edmonton, Alberta, 1 kw. 2 -5 a.m. ` 1380 kc., CMBX, Havana, Cuba, .25 kw. 583 YLZ 3-4 1200 CHAB Sask. 1 CDXR 592 Vienna 3 3-4 1220 KWSC Wash. 1 CDXR 601 SBD 630 CKOV B. 4-4:30 C. 601 CNR 3 - 2 1220 Consolidated Foreign 4-5 KWSC Wash. .1 NNRC 610 I1FI 2 5-5:30 1240 KGKO Texas .25 NNRC "Best Bets" 620 Brussels I 2 4 3-5:10 1400 WIRE Ind. 5 CDXR 625 TIPG 10 5 4:30-5:30 1200 CKNX Ont. .05 CDXR Following is a list of the foreign stations 638 Prague 1 * 6 2-3 1290 KDYL Utah 1 CDXR being heard by Official Observers in different 640 5CK 7 5-6 1370 WMFO Ala. .1 NNRC sections of the U. S. and Canada. Wherever 648 Lyon -la -Dona 5 * 7-8 1210 WSBC Ill. .1 NNRC either an asterisk ( *") or a number appears in a 650 CX6 9 8 2-4 1420 1VJB0 La. .1 CBXR column it indicates that the station has been 658 Cologne 2 630 1 4-4:30 CKOV B. C. heard in the section represented by that column. 650 1YA 5 3 5 5 912:45-1:45 1130 KSL Utah 50 R.News The numbers represent the approximate local 660 XGOA 5 4 Jensen time when the station is heard. Heavy numbers 668 North Regional 6 2-2:20 1420 WJBO La. .1 R. News represent p.m. and light numbers a.m. 670 LS4 9 2 -3 1250 CMKC Cuba 15 CDXR This list is macle up from reports 670 2C0 2:30 -4:30 1320 KID Idaho .25 NNRC observers' as follows: Column 1 (New England)-Observ- 670 JFAK 3 -4 1370 KFRO Texas 1 NNRC ers Birch, Tyndall, Foss, Hammond, Reichardt, 677 Sottens 5 10 2 -3 1530 WIXBS Conn. 1 NRC & Roberts; Column 2 (New York, New Jersey) 695 PTT 5 CDXR Observers Meehan, Maynard, Gaiser, Tomlinson,- 710 LS1 9 11 2:30 -3 1370 WHBQ Tenn. .1 NNRC Kalmbach Jr.; Column 3 (Pennsylvania, Mary- 713 I1 RO 5 6 -6:30 1270 WOOD Mich. .5 CDXR land, Virginia) -Observers Gordon, Kocsan, 720 3YA 14 4:40 -5 1420 KCMG Ark. .1 R. News Marshall, McVey, Wilson, Brus; Column 4 731 EA J -5 5 Halsey (Illinois, Indiana, Minnesota, 731 Tallinn 5-6 1370 WMF(7) Ala. .1 NNRC Nebraska, North Dakota) 740 Munich 1 a 7-8 1210 WSBC Ill. .1 NNRC -Observers Truax, Johnson, Smith, Oleson, Diedrich, Crawford, Biss; Column 5 740 2BL - - 5 15 3:01-3:30 630 CKOV B. C. .1 CDXR (Texas, Alabama, Louisiana, Arkansas) -Ob- 749 Marseille 6 3:30-4:30 1370 KFRO Texas .1 CDXR 750 LR7 8 4-4:30 630 CIiOV B. C. .1 servers Kinrmons, Wood, Deterly, Halsey; Col- 750 KGU 5 * 3 2 3 4-5 1300 WHAZ N. Y. .5 CDXR umn 6 (California)- Observer Hunt. The location and power of the European sta- 750 7NT - 5 4-6 1310 WTRC Ind. .1 NNRC 750 JOBK -1 4-8 1310 WTRC Ind. .1 NNRC tions listed will be found in the European Call List in the December issue; of the TP's, in the 758 Katowice Asiatic Call List in the November issue. 767 South Regional 6 (Note: Official Observers and other readers 770 CX12 9 PERIODIC are invited to send in a listing of foreign stations 770 3L0 5 776 Toulouse 5 * 3 - The times shown for the following stations are, 776 LKF no far as could be determined, correct at the time 785 Leipsig 3 of preparation. However, the hours of A NEW ZEALAND OBSERVER these 790 4YA 5 -* 5- periodic broadcasts are shifted frequently and it L.P.O. Mathie, Hawkes Bay, N. Z., 795 EAJ -1 6 will probably be found that some them of will in addition to being an ardent DX'er 795 Lwow have changed hours by the time this appears in 800 HIX 8 print. is also a member of the Advisory 800 4QG 5 - - 5 Dail Board of the N.Z. DX Club. 804 Nest Regional 6 y- 810 CX14 9 7:30 a.m. 1050 ke., KFBI, Abilene, Kansas, 5 kw (tips) 814 Milan 5 -6 8 8:30 p.m. 1310 kc., WTRC, Elkhart, Ind., .1 kw 815 PRA (tips) (exc. Sunday) 823 Bucharest 830 LR5 8 * 2 7 Tuesdays - 830 3GI 4 - 5 2:30-3 a.m. 900 kc., KSEI, Pocatello, Idaho, 25 kw 841 Berlin Thursdays - 850 CXI6 9 12:30 -1:15 a.m. 1390 kc., KLRA, Little Rock, Ark.; 850 LKB 1 kw. (MCDXE) 859 Strasbourg 6 2 -2:15 a.m. 1300 kc., KFAC, Los Angeles, 1 kw. 868 Paris AGEN 5 (tips) 868 Poznan 8:45 -9 p.m. 1420 kc., KCMC, Texarkana, Ark. 1 kw. 870 LR6 9 * 10 7 - - (Radio News) (tips) 877 London Regional 7 11 -11:13 p.m. 1010 ke., CKCK, Regina, Sask., .5 886 Graz kw. (tips) 895 Limoges Fridays 895 Helsinki - 900 PRF3 7 8 p.m. 1320 kc., WORK, York, Pa., 1 kw. (NRC) (tips) 904 Hamburg 6 8:45 -9 p.m. 1530 kc., W9XBY, Kansas City, Mo. 910 LR2 8 913 4 1 kw. (tips) Toulouse 920 HHK 8 Saturdays - 922 OKB 1 12:01- 12:30 a.m. 980 kc., KDKA, Pittsburgh, Pa., 50 923 PRF4 8 kw., (tips) 932 Brussels II 2 10 -10:15 a.m. 830 kc., WEEU, Reading, Pa., 1 kw. 941 SBB 1 (tips) 941 Algiers 2 3:30 p.m. 1360 kc., WQBC, Vicksburg, Miss., 1 kw. 950 LR3 9 - 7 (tips) 950 Breslau 1

www.americanradiohistory.com 542 RADIO NEWS FOR MARCH, 1936

Kc. Call J 2 3 4 5 6 Our Readers Report - 950 2UE 5 - Observer Birch (Massachusetts) : Verifica- 959 Poste Parisien 5 5 2 tion from LR1, 1070 kc., states that this station 960 YV1RC 8 6 is now in regular operation and desires reports, 960 PRB4 - return postage not necessary. Nice -Cote d'Azur, 960 JOOK - 1185 kc., is also anxious for reports. 980 6AM 5 Observer Foss (Massachusetts) reports hear- 986 I1GE 2 ing Paris on 182 kc. This will he interesting 986 Torun 2 knowledge to owners of the newer receivers that 990 LR4 2 - 2 include a long -wave band. 990 2GZ 5 - - 5 - - Observer Hammond (Maine) : CMQ, now 995 PFBI 3 heard on 880 kc. Some of the all night stations 1005 HJ3ABH - are KFAC, KROW, WNEW, WSMK, WHN 1010 CX24 9 and KPCB. 1010 3HA - Observer Roberts (Massachusetts) : Christmas 1013 Midland Regional 6 time brought the best T. A. reception that I have 1017 PRB9 8 7 ever heard. On the morning of the 24th heard 1020 2KY 5 49 T.A.'s between midnight and 3:30 a.m. On 1022 EAJ -15 5 the 25th heard 9 new Swedish stations. This 1030 LR9 9 brings my total of T.A. broadcast -band stations 1031 CT1GL to 118. 1031 Konigsberg 2 Observer Meehan (New Jersey): WJBW has 1040 CP4 2 - - joined the ranks of 24 -hour stations. WNBX Rennes 5 2 1040 2 is now heard as late as 9 p.m. EST. WHBL 1050 CX26 - - changed to 1300 kc. January 21st. WKAR 1050 South National 5 changed to 850 ke. January 14th. WEHC is 1050 JOHG changing its call to WCHV. Chalked up 578 1059 I1BA 5 BCB stations during 1935 and verified 244. 1068 Paris -Cite 7 Observer Gaiser (New Jersey) : KGU oper- 1070 LR1 8 ates daily from 11:45 p.m. to 4:15 a.m.EST and 1077 Bordeaux 5 2 2 The address is: M. A. Mul- 9 offers a swell veri. 1090 CX28 A SWISS L.P.O. rony & Advertiser Pub. Co., Ltd., Honolulu, 1090 XGOB - - - Hawaii. 1095 EAJ7 6 - 2 Dr. Max Hausdorff, Lugano, Yigan- Observer Tomlinson (New York): CE -62, 1104 Madona 2 CB -62 and will 5 ello, Switzerland, who serves as an 625 kc. has changed the call to 1110 2UW - have a program on the air from 1 -2 a.m., EST, 1113 Radio -Nor- official observer for both the broad- LR3, LS4, PRF4, 7 2 3 Feb. 10th dedicated to IDA. mandie cast band and short waves, is shown Toulouse -Muret (Radio Lyons 1393 kc.), CE -26 1113 OKK 1 here in his "DX Corner" before his and OKR have verified my reception so far this 1120 4BC 6 have 50 other reports out. 1130 CX30 9 18 -tube Midwest. Below is shown a season and I Observer Kalmbach (New York) : Bordeaux, 1131 SBH view of Lake Lugano as viewed from 1113 ke.; and PRD8 8 1077 kc. Radio Normandie, 1132 his home. Rennes, 1'040 kc., were all beard R7 with little 1140 I1TO 5 - 1 CMBY 5 fading, 2 -3:15 a.m from Jan. 1st to 4th. 1149 West National 1035 kc., not 1030. Found re- 1149 North National 5 is operating on 7 ception around Xmas was excellent. On Dec. 26 1150 LR8 9 LR5 with signals running 1160 4MK - 5 heard LS2, LR4 and 5 as high as R9 and very little fading. 1170 4TO - Observer Kocsan (Pennsylvania) also reports 1176 Copenhagen 1 in R4 -R9, Dec. 26th. 1180 3KZ - 5 LR4, LR5 and LS2 coming 6 Observer McVey (Maryland) : Radio Paris, 1185 Nice -Corse 5 -7 8 2 10 - 182 kc. has been heard with good volume, 1190 LS2 Britain, 200 kc., also 1195 Frankfurt 1 * p.m. Droitwich, Great heard, 6 -7 p.m. with good volume. 1200 YV3RC - reception 1204 Prague II Observer Wilson (Virginia) reports * 5 right up to the end of 1935 considerably below 1210 TGW 3 5 Mex- 1213 Lille 2 par, and that the numerous Cubans and 1222 I1TR 2 icans now on the air have not helped to improve 1230 LS8 9 8 7 DX conditions by any means. 1231 Gleiwitz 2 Stanley Brus (Pennsylvania): Up to De- 1240 WKAQ 7 cember let I have received 134 veries. Am at- 1240 Relay Station, tempting to verify every state and now lack only Sweden four. 1249 Juan -les -Pins Observer Truax (Illinois) reports his 1935 1258 Kuldiga log wound up with 436 stations received, 105 1267 Nurnburg 1 verified. He would like to correspond with 1276 Kristianssand DX'ers in foreign countries, especially those in 1280 3AW 5 France and Japan. The name Truax was de- 1282 PRG3 8 rived from the original French De Trieux and 1290 WNEL 7 he would particularly like to correspond with 1294 Linz 2 anyone by that name in France. Letters may be 1295 PRA5 1 addressed to : Donald C. 2ruax, 539 Woodlawn 1312 SBC * Avenue, Aurora, Illinois. 1320 KGMB 5 Observer Johnson (Minnesota) : HRN, 1330 HJ1ABA 3 Tegucigalpa, has shifted frequency to 1350 kc. 1330 Bremen A Mexican announcing only in Spanish, with the 1339 Montpellier 1 call XES or XEF, Tampico, has been heard 1348 2RN * irregularly Sunday mornings until 2 a.m., EST 1348 Paris -Ile de France 2 on 990 kc. The Canadian Radio Commission 1348 Milan II * gives interesting talks on aerials, receivers, etc. 1348 Konigsberg 3 every Tuesday from 10:30 to 10:45, EST. 1366 SCF Eastern Canadian frequency checks take place 1370 CX42 9 on the 20th of each month and sometimes on the 1384 Warsaw II 19th. These occur between 1 and 3:30 a.m., 1385 SCG the past three months this has happened on 810 EST, each station being on for an 8-minute 1393 Lyon - 6 kc. and either CX14 or the Chile station can be period. This month's frequency checks brought 1402 SCE heard. I have a report out now on CX14. On my o i s 765. 1410 2KO - 913, the South American reported there for Observer Floyd Smith (Illinois): Have re- 1411 SCW some time was LR2, he never stays at one place, cently experienced my first T.A. reception after 1438 SCJ I have found him ranging from 895 to 917. trying for 4 years. The stations heard were 1438 HAE -3 Right now he's staying on 910 even. 895 to 898 Fecamp and Rennes with R5 -R6 signals. Have 1447 SCA brings in ZP9 quite often. 1050 is one of the just completed a 650 foot antenna, running west 1456 Eiffel Tower best SA's, CX26. He may be heard behind to east with the lead in at the east end and with 1483 SCD CRCK many nights straight. CX8 has been an average height of 40 feet. It has proved heard here and also by others on 690, while 695 highly directional for eastern stations. is HJN. 750 is a jumble, LR7 several nights Observer Oleson (North Dakota) : CKPR S.A.'s on 810, 890, Etc. has pushed through and can be heard when WJR has moved to 910 kc. Would like reports from Those talks. Also on 750 are a couple in Brazil, one users of the new McMurdo Silver "R9" antenna In the "Reports from Readers" section last in Peru and a Cuban. It's up to the listener to system and the GE "V" doublet -especially as month Observer Gordon (Pennsylvania) had a determine which language is pushing through to their effectiveness on the broadcast band. bone to pick with DX'ers who report South each night. Either Observer Gordon is in a Anyone able to give the desired information may American stations on 810, 890, 913, 1050, 750, poor location, or he can't distinguish between address him as follows: O. Ingmar Oleson, and 690 kc. He had checked these frequencies the three, Portuguese, Spanish and Cuban. Re- Ambrose, North Dakota. constantly and was certain they were occupied ferring to 913, as a French speaking Canadian, Observer Crawford (Nebraska) desires to by Cuban, Mexican, and French Canadian sta- I presume he means our reports on Toulouse. register a complaint against stations which put tions only. Lord, the way this station has been tearing in their unmodulated carriers on the air for periods Observer Tomlinson (New York) doesn't all fall and winter, I don't see how anyone, of up to a half hour or more before starting to check with Observer Gordon and has the follow- especially with a Scott, can mistake him, he's modulate. He feels that any warming up neces- ing to say: `There are several things Observer often better than the Canadian on 910." sary should be accomplished without putting the Gordon should do. First, he should distinguish carrier on the air. between the "Spanish" used by the Cuban sta- 6000 -12,500 -Mile Observer Deterly (Louisiana) reports that tions and that used throughout South America. International Santa Claus left a Yhilco 116B, 11 -tube receiver Second, study just how the letters from A to Z DX Short -Wave Club in his stocking. and the numbers of 1 to 10 sound, when spoken Observer Halsey (Arkansas) : W6XAI, in Spanish. Third, learn approximately what The membership rules of this club have been 1550 kc., Bakersfield, Calif., puts a really good sound split frequencies make when they hetro- altered to include Broadcast Band DX'ers who signal in here from 6 to 10 p.m. with its peak dyne against another channnel 1000 to 5000 have logged and verified stations over 3500 miles occurring from 7 to 7 :30 p.m. cycles away. Fourth, inspect some dozens of distant. Anyone desiring further information Observer Hunt (California) : The DX Season QSL's scattered on the East Coast. Nights when should address an inquiry as follows: Oliver to date has not been comparable with the 1934 - are not coming through, usually Anilie, President, 56th and City Line Avenue, western stations (Turn to page 566) - the South Americans do. Several times during Overbrook, Philadelphia, Pennsylvania.

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 5I3 AMERICAN STATION LIST NORTH AMERICA and the WEST INDIES (Exclusive of the United States) Compiled by John M. Borst

XEAM NORTH Nuevo Laredo, Tams. 750 0.025 CMJA Camaguey AMERICA XFC Aguascalientes, Ags. 1010 0.05 CMCY Havana 1030 1.0 CANADA (temp. 88400 0.35 XERA CMKD Santiago de Cuba 1050 0.25 Call Location kc. kw. Villa Accunaepended) 250.0 CMHA S. la Grande XEFE N. Laredo, Tams. 850 0.25 1070 0.05 CJKL Kirkland Lake, Ont. 530 1.0 XEMO CMCO Havana 1110 0.15 CJRM Moose Tijuana, B. C. 860 2.0 CMGF Matanzas Jaw, Sask. 540 1.0 XEW Mexico, D. F. 890 1120 0.15 CFNB Fredericton, N. B. 550 50.0 CMKM Manzanilla 0.5 -1.0 XENT Nuevo Laredo, Tams. 910 150.0 1120 0.15 CFPR Prince Rupert, B. C. 580 0.05 XEAA CMJI C. de Avila 1130 0.05 CKUA South Edmonton, Mexicali, B. C. 920 0.2 CMBG Havana Alta. 580 0.5 XEFO Mexico, D. F. 1140 0.225 CHRC Quebec, Que. 580 940 5.0 CMJF Camaguey 0.1 XFO Mexico, D. F. 940 5.0 1150 0.2 CKCL Toronto, Ont. 580 0.1 XEAW CMHJ Cienfuegos 1160 0.1 CJOR Vancouver, Reynosa, Tams. 960 50.0 CMBD B. C. 600 0.5 XEAE Tijuana, B. Havana 1170 0.15 CFCF Montreal, Que. 600 0.4 C. (temp. CMJO C. de Avila CRCW suspended) 980 0.25 CMCJ 1180 0.05 Windsor, Ont. 600 0.5 -1.0 XEK Mexico, Havana 1200 0.5 CKOV Kelowna, B. C. D. F. 990 0.1 CMHI Sta. 630 0.1 XES Tampico, Tams. 990 Clara 1210 0.15 CJGX Winnipeg, Sask. 630 0.5 0.25 CMJE Camaguey CECO -1.0 XEAF Nogales, Son. 990 0.75 1220 0.05 Chatham, Ont. 630 0.1 XEBK Neuvo CMCB Havana 1230 0.15 CFCY Charlottetown, P. E. I. Laredo, Tams. 1000 0.1 CMHB Sancti Spiritus 630 1.0 XEBH Hermosillo, Son. 1000 1240 0.05 CJCJ Calgary, Alta. 690 0.1 XEY 0.1 CMKC Santiago de Cuba 1250 CFRB Toronto, Ont. Merida, Yucatan 1000 0.01 CMCG Havana 0.15 690 10.0 XEOK Tijuana, B. C. 1255 0.15 CJCA Edmonton, Alta. 730 1.0 760 2.5 CMHD Caibarien 1270 CFPL at present using 0.2 CMCU 0.25 London, Ont. 730 0.1 XEJ Ciudad Juarez, Havana 1280 0.15 CKAC Montreal, Que. 730 Chih. '1020 1.0 CMOX Havana 5.0 XEB Mexico, D. F. 1030 10.0 1320 0.2 CHWK Chilliwack, B. C. 780 0.1 XEA CMHK Cruces 1330 0.25 C KSO Sudbury, Ont. Guadalajara, Jalisco 1060 0.125 CMJL Camaguey 780 1.0 XEBA Ciudad Cuzman, Jal. 1080 1340 0.075 CFQC Saskatoon, Sask. 840 1.0 XEAS 0.02 CMCA Havana 1350 CRCT Toronto, Saltillo, Coals. 1160 0.05 CMJH 0.25 Ont.. 840 5.0 XEL Mexico, D. C. de Avila 1360 0.05 CFJC Kamloops, B. C. F. 1100 0.25 CMGE Cardenas CRCO 880 0.1 XELO Piedras Negras, Coah. 1370 0.15 Ottawa, Ont. 880 1.0 tem. CMBX Havana 1380 0.2 CJAT Trail, B. C. 910 0.25 XEFL 10.0 CMJC Camaguey 1390 0.15 C RCM Montreal, Que. Tiju ná B. C.) 1150 0.25 CMGC Matanzas 910 5.0 XEWZ Mexico, D. F. 1150 1400 0.1 CFAC Calgary, Alta. 930 0.1 0.1 CMKR Santiago de Cuba XEH Monterrey, N. L. 1150 0.25 1900 0.1 CKPR Fort William, Ont. 930 0.1 XEC CMCR Havana 1410 0.15 CFCH North Bay, Ont. Tijuana, B. C. 1160 0.03 CMJP Moron 930 0.1 XED Guadalajara, Jalisco 1160 1430 0.075 CKPC Brantford, Ont. 930 0.1 2.5 CMOA Havana 1440 CFLC XEU Veracruz, Ver. 1160 0.25 0.25 Prescott, Ont. 930 0.1 XETH Puebla, Pue. CMKF Holguin 1460 0.05 CHNS I-Ialifax, N. S. 930 1210 0.1 CMOK Havana 1.0 XEMZ Tijuana, B. C. 1210 1470 0.15 CRCS Chicoutimi, Que. 950 0.1 0.25 CMCN Marianao 1500 CKY XEFV Ciudad Juarez, Chih. 1210 0.1 0.15 Winnipeg, Man. - 960 15.0 CMCX. Havana CKCD XEAT Hidalgo del Parral, 1500 0.15 Vancouver, B. C. 1010 0.1 Chih. CKWX Vancouver, B. C. 1010 0.1 XEE 1210 0.05 CHWC Regina, Durango, Durango 121"0 0.05 DOMINICAN REPUBLIC Sask. 1010 0.5 XETF Veracruz, Ver. CKCK Regina, Sask. 1010 0.5 1220 0.012 HIX CHML XEFJ Monterrey, N. L. 1230 0.1 Santo Domingo 800 1.0 Hamilton, Ont. 1010 0.1 XELA Saltillo, HIG Santo Domingo CKCO Ottawa, Que. 1010 Coah. 1290 0.05 900 0.05 01 XEME Merida, Vue. 1240 HI4D Santo Domingo 1010 CKIC Wolfville, N. S. 1010 - 0.015 0.025 0.05 XEKL Leon, Gto. 1240 HIT Santo Domingo 1050 CFCN Calgary, Alta. 1030 10.0 XEAI 0.5 HIL Santo 0.1 CKLW Windsor, Ont. Mexico, D. F. 1240 0.1 Domingo 1111 0.02 1030 5.0 XEG Ensenada, B. C. HI4M Santo Domingo ,1150 CRCK Quebec, Que. 1050 1._ 0.02 CRCV (temp. suspended) 1270 0.2 HIJ Santo Domingo 1190 0.01 Vancouver, B. C. 1 100 1.0 XFB Jalapa, Ver. 1270 0.25 HIN Santo Domingo 1220 0.04 CKOC Hamilton, Ont. 1 120 0.5 CHLP -1.0 XEMX Mexico, D. F. 1280 0.012 HI7P Santo Domingo 1300 0.025 Montreal, Que. 1120 0.1 XEX Monterrey, HIZ Santo Domingo CHSJ Saint John, N. B. 1120 N. L. 1310 0.125 1350 0.1 0.5 -1.0 XEAG Cordoba, Ver. HIH San Pedro de Macorís 1391 CKX Brandon, élan. 1120 0.1 XEFW 1310 0.01 HILA 0.075 CHA Moose Jaw, Sask. Tampico, Tams. 1310 0.25 Santiago de los 1200 0.1 XETB Torreon, Coah. Caballeros 1410 CKNX Wingham, Ont. 1200 0.05 1310 0.125 HI5N 0.05 CKTB St. XECW Mexico, D. F. 1310 0.01 Santiago de los Catharines, Ont. 1200 0.1 XFD Jalapa, Ver Caballeros CJCS Stratford, Ont. 1210 1340 0.35 1440 0.1 0.05 XEI Morelia, Mich. HIBQ Santo Domingo 1475 CJCU Aklavik, N.W.T. 1210 0.05 XEFZ 1370 0.125 0.025 CKBI Prince Mexico, D. F. 1370 0.1 Albert, Sask. 1210 0.1 XEZZ San Luis Potosi, CKMC Cobalt, Ont. 1210 HAITI 0.05 S.L.P. 1370 CKCH Hull, Que. 1210 0.1 XEAZ 0.1 CJOC Lethbridge, Guanajuato, Gto. 1420 0.007 HHK Port -au Prince Alta. 1230 0.1 XEFB Monterrey, N. L. 920 1.0 CJCB Sydney, N. S. 1240 1.0 1420 0.1 CERN Edmonton, XEFI Chihuahua, Chih. 1440 0.25 Alta. 1260 0.1 XEFA Tacuba, D. F. CKCV Quebec, Que. 1310 0.1 ... 0.5 CJLS Yarmouth, N. S. 1310 0.1 CHCK Charlottetown, P.E.I. 1310 0.05 MIQUELON CKCW Moncton, N. 13. 1370 Meter Switching CJRC Winnipeg, Man. 1390 0.1 FQN St. Pierre 609 0.25 CHNC New Carlisle, Que. 1410 0.5 -1.0 C KFC Continued from page 529) Vancouver, B. C. 1410 0.05 NEWFOUNDLAND CKMO Vancouver, B. C. 1410 0.1 the plate supply. CKGB Timmins, Ont.. 1420 0.1 CKNC Toronto, VOWR St. John's A word about the meters; use a milliammetér Ont. 1420 0.1 681 0.5 large enough to accommodate CFCT Victoria, B. C. 1450 0.05 VOGY St. John's 840 0.4 the tube drawing CHGS Summerside, VOAS St. John's the highest current. Likewise, the voltmeter P.E.I. 1450 0.05 940 0.1 must be capable of CJIC Sault St. Marie, VOAC St. John's reading, at least, the maxi - Ont. 1500 0.1 1065 0.04 mum voltage on any C I

www.americanradiohistory.com MARCH, 1936 544 RADIO NEWS FOR D X for the

Conducted by Laurence

of the month. In this way you share your A PALESTINE DX CORNER Radio Fellowship, M. H. Ryder, Chair- man; Short Wave Club of New York, "Best Catches" with other readers and Introducing W. E. Frost, L.P.O. for they, in turn, share with you, making for an II -tube Philco, H. C. Lange, President. Palestine. He uses Any DX fan wishing to join any one of improved knowledge on short -wave recep- 6 and a 1 -tube, home - or a -tube RCA these Clubs or Associations may write for tion. Also send in any corrections built, short -wave set. His antennas DX Editor, additions that you can make to the short- a ". information to the Short -Wave are a doublet and "spider be sent to the organi- wave identification charts, including sta- and his letter will an- zation in question. Other Clubs who wish tion addresses, station slogans, station THE thirty -sixth installment of the nouncements, and any identifying signals con- to become affiliated should make their ap- DX Corner for Short Waves DX Editor. the stations may have. Short -Wave Time -Table plication to the Short -Wave tains the World Clubs associated with the DX Corner have for 24 -hour use all over the world. A GO- GETTER ON SHORT the privilege of sending in Club Notes for WAVES Clubs publication in RAmo NEWS. Affiliated DX Gus Bartsch, Official Listening Post We are hereby placing a standing "Legal" Wavelength Calcu- Observer for Illinois, at his home in invitation to reliable DX Clubs to be- lations Chicago sends greetings to other come affiliated with the DX Corner as readers. Members, acting as advisers In accordance with the vote taken a Associate as to whether we should adopt 'on short -wave activities, in promoting month ago and reception the "legal" basis for calculating wave- short -wave popularity -wave A list of associate organiza- lengths from the frequency of short efficiency. broadcasting stations, as adopted by inter- tions follows : International DX'ers Charles A. Mor- national convention, or retain the more Alliance, President, on the latest rison; Newark News Radio Club, A. accurate calculation based Secretary; So- findings of the speed of electromagnetic W. Oppel, Executive Time -Table this month will ciety of Wirelesss Pioneers, M. Mickel - radiation, the U. S. Radio DX be found to have a revised wavelength son, Vice -President; Listening Post Observers and Club, Geo. E. Deering, Jr., President; listing. Our Venezolano, Vene- other readers voted almost unanimously in the Radio Club wavelengths. zuela, President, R. V. Ortega; The favor of the "legal" World -wid'e Dial Club, President, Your DX Logs Welcome International 6000 - Howard A. Olson; Please keep on sending in your informa- to 12,500 -Mile Short -Wave Club, Oli- H. Miller, tion on any S.W. stations that you hear ver Amlie, President, Joseph month, getting them in Globe Circlers DX during the coming Vice -President; to the short -wave DX Editor by the 20th Club, W. H. Wheatley, President; ORIGINAL ORGANIZATION OF THE WORLD'S Waters, Robert L. Weber, J. Ira Young, New York, Donald E. Barre, John M. S. W. PIONEERS Evert Anderson, Eddie Zarn, Louis Hor- Borst, H. S. Bradley, William C. Dorf, wath, Jr., Heinie Johnson, Gus Bartsch, Capt. Horace L. Hall, Robert F. Kaiser, Arthur Evans, Leo Herz, Bruce Holmgren; I. H. Kattell, W. B. Kinzel, William Koehn - Official RADIO NEWS Listening Indiana, Freeman C. Balph, Arthur B. lein, T. J. Knapp, A. J. Leonhardt, Joseph in America Coover, B. L. Cummins; Iowa, Clarence M. Malast, S. Gordon Taylor, Edmore Post Observers Norman, Kansas, William Schumacher; Melanson, Joseph H. Miller, R. Wright, are the Official Kentucky, W. W. Gaunt, Jr., George Krebs, Harry E. Kentzel, Howard T. Neupert, LISTED below by states C. Doty, Jr., Thaddeus Grabek, Kenneth Short-Wave Listening Post Charles Miller, William A. McAlister, James A. RADIO NEWS in T. Spalding, J. E. Wilson; Louisiana, Roy L. Sargent, Robert J. Flynn, George Pas- Observers who are serving conscientiously quale, Frank J. Flora, James E. Lynch, for the DX Corner. W. Peyton; Maine, Danford L. Adams, logging stations M. Keith Libby, Vincent M. Wood, R. C. Pierre A. Portmann, A. J. Umlauf ; North W. C. Couch, E. Payson Mallard, United States of America Messer ; Maryland, Howard Adams Jr., Carolina W. Dodge, Lyman F. H. O. Murdoch, Jr. ; North Dakota, Billie E. Brooks, L. T. Lee, Jr., J. F. Fritsch, Forrest Alabama, J. A. Barry, Oliver Hersowitz ; Massachusetts, Bundlie ; Ohio, Paul Byrns Charles Dooley, D. Owens ; Alaska, Thomas Elcheshen, Albert E. Emerson, Samuel William Moore, Caleb A. Armand A. Boussey, Walter L. Chambers, Stan Pugh; Arkansas, James G. Arthur Hamilton, Sydney G. Millen, Harold J. Emerson, R. W. Evans, Clarence D. Hall, Claude H. Dalrymple, Charles Roy Sanders, Donald W. Shields, C. H. Skatzes, Orval Wilkinson, S. Allen, K. Miller, Elmer F. Orne, Holt ; California, Eugene Smith, Robert Loring Young, James Dickes, Edward DeLaet, M. L. Gavin; H. Canning, Earl n, A. n. Donald H. L. Pribble, Robert Woods, Berger, C. Howald, Wesley B. Robbins, George James Ellsworth, Albert Oklahoma, G. C. Gallagher, Werner I. Pickering, Jr., W. C. Reichardt, Francis W. H. Boatman; Oregon, Harold H. Flick, W. Loudon, Robert J. McMahon, Oriente Ralph B. Baldwin, George R. Johnson, James Haley, Ernest R. James E. Moore, J. Reilly ; Michigan, Noda, George C. Sholin, R. Ruple, Jerry M. Hynek ; Min- Remster, Ned Smith, Virgil C. Tramp; Stewart Harold W. Bower, Roy L. Douglasá S. nesota, M. Michaelson, E. M. Norris, Dr. Pennsylvania, H H. hParker, FFred A Pigrim, W. Twomey, Walter F. Johnson, Preston Christoph, John Leininger, George Lilley, Andrews, Fred M. Craft, G. C. Lips, Charles Nick, Hen Catchim, Frank ; Mississippi Mrs. L. R. Led- Edward F. George C. Akins; Colo- C. Richardson T. Sheaks, K. A. Staats, Radio Fellowship, Kemp, better; Missouri, C. H. Long, Walter A. Plom, C. F. L. Connecticut, H. Walter W. Winand, J. B. -. rado, Wm. J. Vette; Herbert Greiner, R. C. Ludewig, Merton T. Meade, Stitzinger, Can George A. Smith, Philip Swanson, F. Miller; Montana, Henry Dobro. field, Charles B. Marshall, Jr., S. G. De District of Columbia, Phillip R. Lewis H. Marco, R. H. Graham, Thomas P. Jordan, I. Hyde; H. volny ; Nebraska, Hans Andersen, P. Florida, James F. Dechart, George T. Haws, C. W. John G. McConomy, Steve Scibal, Jr., Belt; H. Arm - Clute, Harold Hansen, Louis Fletcher, E. M. Law ; Georgia, C. Don H. Townsend Jr.; Puerto Rico, Manuel E. Betances, A. N. Bigbee, James L. Davis, Bourne; Nevada, Rhode Island, Carl Schradieck, strong, Guy R. New Hampshire, Paul C. Atwood, Alfred J. Lightbourn; R. W. Winfree, Owen Reeve; V. Trzuskowski, Spencer E. Lawton ; Mc Carley, ; William Dixon, Mor- Joseph John Lawrence Swenson; Mannix New Jersey, Edward Bahan, Ben F. Idaho, Bernard Starr, gan Foshay, George Munz, R. H. Schiller, South Carolina, Larry Eisler, Robert ; Dakota, Paul J. Mraz; Illinois, E. Bergeman, Paul B. Silver, Earle R. Wickham, George Goodlett South R. O. Lamb, Charles A. Morrison, K. Tennessee, Charles D. Moss, Eugene T. Irving, Floyd W. Osbahr ; New Mexico, G. Harrison; Phillip Simmons, Ray A. Walters,

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 545 Corner SHORT WAVES

M. Cockaday THE SKAMLEBAEK TRANSMITTER To save a lot of wasted effort for our Also include station slogan, power, owner This is the transmitter hall in which editors it would be best if our Observers and address if available. the station OXY is located. This use a standard form for their reports of equipment takes up the whole of the new stations or station changes. We have Listening Post Observers and extreme right side Of the building. found a system of paragraphs, in exactly the following procedure, most convenient: Other Fans Please Notice "W2XAF, Schenectady, N. Y., 31.4 Listed in next column is this month's DJH, Zeesen, Germany, 14460 1cc., meters, 9530 kc., daily 4 p.m. to midnight, partial information regarding short -wave 20.75 meters, reported heard. (Craft, E.S.T." stations heard and reported by our World - Lawton, Libby.) In other words, use one paragraph to an Wide Listening Posts. Each item in the DJI, Zeesen, Germany, 9675 kc., item and indicate whether data is from a listing is credited with the Observer's sur- 31.01 meters, reported heard 1 -7 p.m., veri, an announcement, or other source. name. This will allow our readers to note E.S.T., talking German and French who obtained the information given. If with repeated notes from a music box. any of our readers can supply actual Time (Floyd, Berts, Baier, Hammersley, NEW JERSEY HEARD FROM Schedules, actual Wavelengths, correct Fre- Miller, Adams, Salazar, Craft, Stayles Here is the Listening Post of .4 quencies, or any other Important Infor- Davis.) Monaghan, of Glen Ridge, New mation regarding these items, the DX Cor- DJJ, Zeesen, Germany, 10040 kc., Jersey, an ardent reader of RADIO ner Editor and its readers will be glad to 29.88 meters, reported heard. (Reich- News for short -wave activities. get the information. There are some hard ardt, Putnam, Craft, Lawton, Ham - stations to pull in in these listings, but we mersley, Libby, Bower.) urge our Listening Posts and other readers DJR, Zeesen, Germany, 15340 kc., to try their skill in logging the stations 19.5 meters, reported heard. (Bower.) and getting correct information about DJP, 11855 kc., 25.31 meters, re- them. When you are satisfied that you ported heard, starting transmission at have this information correct, send it in 2:15 a.m., E.S.T. (Bower.) to the editor; or if you have received a DIP, Koenigswusterhausen, Ger- "veri" from any of the hard -to -get sta- many, 14410 kc., 20.82 meters, relaying tions, send in a copy of the "veri" so that special program to Africa at 12 noon, the whole short -wave fraternity may bene- E.S.T. (Styles.) fit. The list containing this information DJQ, 19.63 meters, heard Sundays follows: with same program as DJB, at 5 :10 a.m., E.S.T. (N. C. Smith, Salazar, Europe Davis.) Some new experimental German DIQ, Germany, 10290 kc., broad - transmitters are reported as follows: (Turn to page 548) SHORT -WAVE LISTENING POST OBSERVERS Musser, Darrell Barnes; Territory of Ha- Belgium, Rene Arickx. C. K. McConnan, Douglas Thwaites, J. waii, O. F. Sternemann; Texas, James Bermuda, Thurston Clarke. Rowson, A. J. Webb, F. Crowder. Brown, Carl Scherz, Bryan Scott, James Brazil, W. W. Enete, Louis Rogers Gray, France, J. C. Meillon, Jr., Alfred (jvaglino. W. Sheppard, John Stewart, Overton Wil- Flavio Mascarenhas. Germany, Herbert Lennartz, Theodor B. son, Isaac T. Davis, Arthur Immicke; Utah, British Guiana, E. S. Christiana, Jr. Stark. Earl Larson, A. D. Ross; Vermont, Eddie British West Indies, D. G. Derrick, Edela Holland, L. Hintzbergen, R. Groeneveld. H. Davenport, Dr. Alan E. Smith, John Rosa, N. Hood- Daniel, Aubrey H. Forbes. India, D. R. D. Wadia, A. H. Dalai, Terry Eagan; Virginia, G. Hampton Allison, L. P. Canada, J. T. Atkinson, A. B. Baadsgaard, A. Adams, Harry J. Dent. Morgan, D. W. Parsons, Gordon L. Rich, Jack Bews, Robert Edkins, W. H. Fraser, Iraq, Hagop Kou: oumdjian. Gaines Hughes, Jr., E. L. Myers, A. T. Fred C. Hickson, C. Holmes, John E. Irish Free State, Ron. C. Bradley. Hull, Jr., Wheeler T. Thompson, E. W. Moore, Charles E. Roy, Douglas Wood, Italy, A. Passini, Dr. Guglielmo Tixy, Turner; Washington, Glenn E. Dubbe, Claude A. Dulmage, A. Belanger, Robert Japan, Masall Satow, Tomonobu Masuda. A. D. Golden, Charles G. Payne, J. Wendell B. Hammersley, Cyril G. Clark, Fred Malta, Edgar J. Vassallo. Partner, Jack Perry ; West Virginia, Ken- Cox. Manchukuo, Anatol Kabatoff. neth R. Boord, R. E. Sumner, Fred C. Canal Zone, Bertram Baker. Mexico, Felipe L. Saldana, Manuel Ortiz Lowe, Jr.; Wisconsin, Willard M. Hardell, Canary Islands, Manuel Davin. G. Walter A. Jasiorkowski, E. L. Frost; Wyo- Chile, Jorge Izquierdo. New Zealand, Dr. G. Campbell Macdiarmid, ming, L. M. Jensen, Dr. F. C. Naegeli, Eric China, Baron Von Huene. Kenneth H. Moffatt, B. A. Peachey. Butcher. Colombia, J. D. Lowe, Italo Amore. Newfoundland, Frank Nosworthy. Cuba, Frank H. Kydd, Dr. Evelio Villar, Norway, Per Torp. RADIO Augusto Anca, Juan Manuel Salazar. Palestine, W. E. Frost. Official NEWS Listening Czechoslovakia, Ferry Friedl, Joe Klar. Panama, Alberto Palacio. Post Observers in Other Denmark, Hilbert Jensen. Peru, Ramon Masias. Dominican Republic, Jose Perez. Philippine Islands, Victorino Leonen, Countries Dutch East Indies, E. M. O. Godee, A. den Johnny Torres. Breems, J. H. A. Hardeman. Portugal, Jose Fernandes Patrae, Jr. LISTED below by countries are the Offi- Dutch West Indies, Rein J. G. van Om- Scotland, Duncan T. Donaldson. cial RADIO NEWS Short-Wave Listening meren. South Africa, Mike Kruger, Post Observers who are serving conscien- A. C. Lyell, H. El Salvador, Tose Rodriguez R. Mallet -Veale, C. McCormick, H. West - tiously in logging stations for the DX England, N. C. Smith, H. O. Graham, Alan man. Corner. Barber, Donald Burns, Leslie H. Colburn, Spain, Jose Maria Maranges. Argentina, J. F. Edbrooke, Santiago E. C. L. Davies, Frederick W. Gunn, R. S. Straits Settelements, C. R. Devaraj. Roulier. Houghton, W. P. Kempster, R. Lawton, Sweden, B. Scheierman. Australia, Albert E. Faull, A. H. Garth, John J. Maling, Norman Nattall, L. H. H. Arthur Matthews, Switzerland, Dr. Max Hausdorff. C. N. H. Richard- Plunkett -Checkemian, Harold J. Self, R. Turkey, Hermann Freiss, M. Seyfeddin, A. son, R. H. Tucker, Harold F. Lower, Stevens, L. C. Styles, C. L. Wright, John K. Onder. E. O. Stafford. Gordon Hampshire, J. Douglas Buckley, Venezuela, Francisco Fossa Anderson.

www.americanradiohistory.com 546 RADIO NEWS FOR MARCH, 1936

WORLD SHORT -WAVE TIMETABLE.

Compiled by LAURENCE M. COCKADAY Hours of transmission for the World's Short Wave Broadcast Stations

FILL IN LOCAL TIME

8 9 10 11 M í 2 3 4 5 6 7 EASTERN STANDARD TIME 8 9 10 11 N 1 2 3 4 5 6 01 02'03 04 05 06 01 08 09 10 11 12 GREENWICH MEAN TIME 13 1415 16 17 18 19 20 21 22 23 00

Wave - HOURS OF Frequency HOURS OF TRANSMISSION TRANSMISSION lents Letters Kc. C wintry D 13.95 W8XK 215'40 Pittsburgh, Pa. O X5 O 13.93 GSJ 21530 Daventry, England D 13.94 W2XE 21520 New York, N. Y D 15.93 PLE 18830 Bandoeng, Java G x5 D 16.86 GSG 17790 Daventry, England QD 00 16.87 W3XAL 17780 Bound Brook, N. J XS AS AS 16.89 DJE 17760 Zeesen, Germany D O D D 19.52 HAS3 15370 Budapest, Hungary S 5 19.57 W2XAD 15330 Schenectady, N. Y S s S S o S DO D 19.63 DJ() 15280 Zeesen, Germany Do 19.65 W2XE 15270 New York. N. Y. D p D O D D D D D D 19.66 GSI 15260 Daventry, England D D D D Yh Do 19.68 FYA 15244 Pontoise, France 0 0 0 T T T W I '19.71 PCJ 15220 Huizen, Holland I S I 19.72 W8XK 15210 Pittsburgh, Pa. D D D O D O D D OD D O D D O D 19.74 DJB 15200 Zeesen, Germany D D O ' D DS XS D 19.82 GSF 15140 Daventry, England D o D O OD x5 19.84 HVJ 15121 Vatican City I DO O D D O 19.95 RKI 15040 Moscow, U. S. S. R D D D 20.55 JVH 14600 Nazaki, Japan Z Amp D 0 0 0 0 21.25 HJ5ABE 14120 Cali, Colombia D O fS o D D 22.00 SPW 13635 Warsaw. Poland S S 22.73 ORP 13200 Ruysselede, Belgium D O X X X %5 XS 22.95 VPD 13075 Suva. Fiji Islands 23.38 CNR 12830 Rabat, _Morocco S S S 24.,52 TFJ 12235 Reykjavik, Iceland S 24.83 CTICT 12082 Lisbon, Portugal S S S E E V S 25.00 RV59 (ave) 12000 Moscow, U. S. S. R. 5 SS SS 25.21 CTIGO 11900 Parede. Portugal S S XX XX xx O 25.2.5 FYA 11880 Pontoise, France O D O ' D O D O 25.27 W8XK 11870 Pittsburgh, Pa. D OD 25.30 GSE 11860 Daventry, England D 00 DO 25.35 W2XE 11830 New York, N. Y DD D O D O 25.38 HJ4ABA 11820 Medellin, Col D 00 D O LD I 25.40 12R0 11810 Rome, Italy D 0 0 0 0 0 25,44 WIXAL 11790 Boston. Mass. 55 S 25.49 DJD 11770 Zeesen. Germany o O O O O 25.53 GSD 11750 Daventry, England DO 00Th D D 25.55 PHI 11730 Huizen, Holland P P P D O x5 x5 25.60 CJRX 11720 Winnipeg, Canada D D Do 25.60 FYA 11720 Pontoise, France D 0 SS O OD 27.27 PLP 11000 Bandoeng, Java D 00 D 2 X = X X. 2 X X 27.93 JVM 10740 Nazaki, Japan A 28.12 CEC 10670 Santiago, Chile 2 O = O L = 2 2 S 2 X 28.14 JVN 10660 Nazaki, Japan I 29.04 ORK 10330 Iuysselede, Belgium D Om X X O 29.24 PMN 10260 Bandoeng, Java D O S' I DO - 30.43 FAQ 9860 Madrid, Spahi S I D OD K K 31.00 CON 9677 Macao, Asia C 31.14 12R0 9635 Rome, Italy D O O CC. 31.25 CTIAA 9600 Lisbon, Portugal G G G S M 31.27 HBL 9595 Geneva, Switzerland Sa Sic 31.28 W3XAU 9590 Philadelphia, Pa. 0 0 0 0 0 0 S5 5 55 31.28 VK2ME 9590 Sydney. Australia 5 5 5 5 o D O 31.28 HP5J 9590 Panama City, Pana. 5 55 5 O X5 O O X5 X5 XS X5 X5 X5 31.32 VK3LR 9580 Lyndhurst, Australia O 31.32 GSC 9580 Daventry, England D D' D D D O D D X5 D 31.35 W1XK 9570 Millis, Mass. O DO [DOD O O D O O D S I LS, 31.36 VUY(VUB) 9565 Bombay, India 2 2 = X. D O O 00 II 31.38 DJA 9.560 Zeesen, Germany D D D O D 00 0 0 o 0 D D D D D D D 31.45 DJN 9540 Zeesen, Germany D O D D D DO, D O D O 31.48 W2XAF 9530 Schenectady, N. Y. 00 DO D D O D D 31.48 LKJI 9530 Jeloy, Norway O O D O O D O X5 X5 31.55 VK3ME 9510 Melbourne, Australia DO 5 31.55 GSB 9510 Daventry, England O O D D O O O O D D D 5 S 31.58 PRFS 9501 Rio de Janeiro, Bras. o OS D O D S X 31.82 COCH 9428 Havana, Cuba DO D O- D D O 31.86 PLY 9415 Bandoeng, Java 32.88 HAT4 9125 Budapest, Hungary S 32.89 CP6 9120 La Paz, Bolivia DO X xM, %MXM XM AL 33.71 HCJB 8900 Quito, Ecuador 5S S o o D AM x5 O O D O 34.29 ZCK(ZBW) 8750 Hong Kong, China D O SO. OD 36.50 ZPIo 8220 Asuncion. Paraguay D O D XA, 36.72 CO9JQ 8170 Camaguey, Cuba 37.34 CNR 8035 Rabat, Morocco S O O o D D O 38.20 1-1C2JSB 7854 Guayaquil, Ecuador D 38.48 HBP 7797 Geneva, Switzerland 5a Sa D O O 40.51 HJ3ABD 7406 Bogota, Colombia ),S X5 D D 0 40.65 XECR 7380 Mexico City, Mex. 55 X5 x5 41.20 HJIABD 7281 Cartagena, Colombia L L L X5 41.80 CR6AA 7177 Lobito. Angola, Afr. L L L 42.15 HB9B 7118 Basle, Switzerland W 42.36 PI1J 7082 Dordrecht, Holland 54 Sct 43.48 I-113C 6900 La Romana, D. R. O D O O D O 44.00 1-11H 6818 San Pedro, D. R. DO S O I XI Do 00 44.44 JVT 6750 Nazaki, Japan Z D D X Y 44.71 TIEP 6710 San Jose, Costa Rica SO D 5a 44.95 YVQ 6672 Maracay, Venezuela 52 T T T 44.99 HC2RL 6668 Guayaquil, Ecuador 5 55 Th Th Th 45.34 PRADO 6616 Riobamba. Ecuador T T D D 45,38 RV72 6611 Moscow, U. S. S. R. _ Th Th 45.80 TIRCC 6550 San Jose, Costa Rica 5 O O O D DO 46.01 YV6RV 6520 Valencia, Venezuela O D O 0 0 0 46.22 HJ3ABD 6490 Cali. Colombia N

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 547

WORLD SHORT WAVE TIME-TABLE

(Continued front the Previous Page) Hours of transmission for the World's Short Wave Broadcast Stations

FILL IN LOCAL TIME

8 9 40 11 M 4 2 3 4 5 6 7 EASTERN STANDARD TIME 8 9 10 11 N 1 2 3 4 5 6 7 01 02 03 04,05 06 0/ 08 09 10 1i 12 GREENWICH MEAN TIME 13 14 15 16 17 18 19 20 2 22 23 00 Wave - length Call Frequency City HOURS OF TRANSMISSION Meters Letters Kc. Country HOURS OF TRANSMISSION 46.28 HI4D 6482 Santo Domingo, D. R X5 K5 K5 X5 X5 X5 X5 D D L 46.53 HJIABB 6447 Barranquilla, Col. O 0 0 5 D DO M. D O t 46,80 TIPG 64!0 San Jose, Costa Rica 2 M D O O S S 1 47.06 YV4RC 6375 Caracas. Venezuela. D D D D O D 47.24 HRP1 6350 San Pedro Sula, D. R p o o D r X 54 54 47.51 HIZ 6315 Santo Domingo, D.R. 5 5 5 MI MS r S S 47.62 VV!2RM 6300 Maracay, Venezuela _ 2 2 47.62 VUC 6300 Calcutta, India .t 2 O O Sic t_ 1.- L 48.15 OAX4G 6230 Lima, Peru L AM 48.19 HJIABH 6225 Cienaga, Colombia qM o O Z 1 2 Y 48.48 HI IA 6188 Santiago de los z z O O Caballeros, D. R. ,jcs Xs o 48.54 HJ3ABF 6180 Bogota. Colombia O X5 5 5 5 5 55 48.70 \'PB 6160 Colombo, Ceylon 0 0 0 0 0 O D X5 XS 48.70 CJRO 6160 Winnipeg, Canada O O O 48.78 HJ2A BA 6150 Tunja, Colombia D O o o O 48.78 YV3RC 6150 Caracas, Venezuela D O O O O O O XA XA S S 48.78 HJ5ABC 6150 Cali, Colombia D S 5 X.A. 0 D D F M M 48.78 CO9GC 6150 Santiago, Cuba D D O D o D D D O O 48.86 AV8XK 6140 Pittsburgh, Pa 48.90 CR7AA 6135 Lourenzo.Marques, AC AC AC Mozambique AE AE 48.92 ZGE 6132 Kuala Lumpur,F.M.S AE , O O O D 48.94 COCD 6130 Havana, Cuba O O Xs( 48.94 CT -IGO 6130 Parede, Portugal 5 5 5 XY D 49.02 W2XE 6120 New York, N. Y XA XA M M 49.04 HJIABE 6115 Cartagena, Col. XA XA 5 X5 D O D O O 49.10 VE9HX 6110 Halifax, N. S. O XA XA X XNXA XA O 54 O O D 49.10 GSL 6110 Daventry, England O O O O Th O Z r 5 49.18 HI4ABB 6100 Manizales. Col. XA 5a 49.18 W3XAL 6100 Bound Brook, N. J. AH R R P. R RAN 49.18 W9XF 6100 Chicago, III. D X5 X5 AL D O DO 49.20 ZTJ (JB) 6098 Johannesburg, . \frica X5 X5 X5 XS O O' O O 54 o O o D 49.26 CRCX 6090 Toronto, Canada S 5 5 5 D D O O XA XA 49.32 VQ7LO 6083 Nairobi, Kenya, .\ fr. E E O D O XS 54 49.34 CP5 6080 La Paz, Bolivia 2 I I 49.34 W9XAA 6080 Chicago, I l l . X5 X5 O O 00 D O D S 5 5 X5 49.34 ZHJ 6080 Penang, Straits Settle, x5 ments ox Mr I 49.41 OER2 6072 Vienna, Austria S 0 0 0 D D D D O O 5. X5 49.42 HH2S 6070 Port au Prince. Haiti 5 5 5 AG AG "r 49.42 VE9CS 6070 Vancouver, B. C. S S 5 S S D D D O Sa. 5a 5w. 49.46 HJ4ABI. 6065 Manizales, Colombia D O O O D O O Sa. XS X5 49.50 WSXAL 6060 Cincinnati, Ohio 0 O D O O D p 0 0 0 o O D O 49,50 \V3XAU 6060 Philadelphia, Pa. D 49.50 OXY 6060 Skamlehaek, Denmark SS DO 10 0 0 0 49.59 GSA 6050 England O O D 49.63 HJ3ABI 6045 Bogota, Col bia XS X6 X.5 Sa 49,65 HJIABG 6042 Barranquilla, Col. X5 X5 S 5 5 5 X5 E 49.67 \VIXAL 6040 Boston, Mass. 5 5 5 IE D O 0 O 49.67 W4XB 6040 Miami, Fla. D D D O O O D 49.67 PRAS 6040 Pernambuco, Brazil 0 0 0 D D X5 D O D O D O O 49.75 HP5B 6030 Panama City, Pana. D S D O 0 0 D Th Th 49.75 VE9CA 6030 Calgary, Alberta, Can. X5 XS XS D O O XS 5 5 D D D O 49.83 DJC 6020 Zeesen, Germany t Do D D D O O O

S i 49.83 XEUW 6020 Mexico City, Mex. D I O 5 5 5 S N N 49.85 ZHI 6018 Singapore, Malaya N D O O Z 49.90 HJ3ABH 6012 Bogota, Colombia 0 0 0 0 S S D O 54 54 49.92 COCO 6010 Havana, Cuba D O O D D D D o o D D 49.95 HJIABJ 6006 Santa Marta, Colom- D D bia 5.. 49.96 VE9DN 6005 Montreal, Canada O o o t 0 O 50.00 XEBT 6000 Mexico City, Mex. D O O O O D D O O o 50.O0 RV59 6000 Moscow, U.S.S.R. S r O D XTh Z. Z S¢ 54 50.17 HIX 5980 Santo Domingo, D.R. O E O O 2 50.20 HJ2ABC 5976 Cucuta, Colombia DO O O 50.21 XECW 5975 Xantocam, Mexico E Th 50 25 XEV1 5970 Mex. City. Mexico S C S 50.26 HVJ 5969 Vatican City D D o O 50.42 HJN 5950 Bogota, Colombia 50 -4.5 FIQA 5946 Tananarive, Mad. D At AC 50.50 TG2X 5940 Guatemala City, Guat. O D D 50.59 HJ4ABE 5930 Medellin, Colombia O D O DO X5 51.02 YVBRB 5880 Barquisimeto, Ven. XS XS O O S SI 06 JRN 5875 - Tegucigalpa. Hood's D S S DD X5 X5 - SI 28 YV5RMO '5850 Maracaibo, Ven. X5 XS 5 5 X5 X5 x5 o D 51.63 YV7RMO 5810 Maracay, Ven. D O O D D o O Y 51.72 YV2RC 5800 Caracas, Venezuela SS 0 0 0 5 5 0 0 0 0 AH AH AH 51.0 OAX4D 5780 Lima, Peru AN AN AN O D D D 52.45 YVIORSC 5720 San Cristobal, Ven. O D D Y D O O D O D 70.21 RVI5 4273 Khabarovsk, Siberia D D O I 79.58 HB9B 3770 Basle, Switzerland W

A- Thursday, Sunday P- Except Tuesday, Wednesday AC- Tuesday, Sunday C- Monday, Wednesday, Friday R- Thursday, Friday, Sa t urday AH- Monday, Wednesday, Saturday P- -Daily S- Sunday AL- Except Monday, Sunday F, Tuesday, Thursday T- Today AM- Monday, Thursday F- Friday Th- Thursday AN- Tuesday, Saturday h'- Tuesday. Thursday, Saturday W- Wednesday Sa- Saturday I- Irregularly XTh-Except Thursday NA- Except Saturday, Sunday K.-Monday. E riday Y- Sunday, Monday NM -Swept Monday I- \\'cdnesday, Saturday Z-Tuesday, Friday ES- Except Sunday SI- Monday AC- Monday, Thursday, Saturday EX- Tuesday, Thursday, Friday N- Monday, AA'cdne-da,y. Thursday AE- Tuesday, Friday, Sunday XY-Except Tuesday, Sunday

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936

A RARE VIEW OF TIIE EAQ TRANSMITTER This is the transmitter room of the famous Madrid Station EAQ, the first one we have seen and one that should be interesting to our readers the world over. A CANADIAN LISTENER ENDORSES TIME -TABLE Mr. James Burton, Sherbrooke, Canada, would not be without the RADIO NEWS Short -lVave Time -Table for its help in locating short -wave stations at various times of the day. Mr. Burton is very successful in pulling in DX sations. The DX Corner JIB, Taiwan. Formosa. 10350 kc., re- evening between 8 and 9 p.m., E.S.T.? ported heard 3 a.m., E.S.T. ( Craft.) (Canighem.) Waves) A new Japanese station has been What station around 9000 kc. calls (Short heard on 5100 kc., approximately, but "Muscovia" around 1 a.m., E.S.T., al- (Continued from page 545) no call letters could be distinguished. most daily? (Hull.) This was at 3:15 a.m. to 4 a.m., E.S.T. AFRICA casts news in English 8:30 p.m.. E.S.T. (Craft.) They are heard regulariy 5 -7 p.m., Dutch East ETA, Addis Ababa, Ethiopia. 18280 -1:30 p.m., YDA, Tandjongprick, kc., reported heard. (Owen.) Also re- E.S.T., and often at 12:25 Indies, 49.67 meters. 10 kw., heard E.S.T., (Torres, Barry, Miller.) ported heard on 24.5 meters. testing at 5:50 a.m., Sundays, and at ETB, Addis Ababa, Ethiopia, re- CTV, Monsanto Radio. Lisbon, 9:30 -10 p.m., E.S.T. (N. C. Smith, Portugal. testing on 26.91 meters at ported heard on the following fre- Craft.) quencies, 11555 kc., 11850 2 p.m., E.S.T. (Vasallo.) kc., 11980 PMN, Bandoeng, Java. 10260 kc., 60 kc. Wavelengths reported as follows: I2R0, Rome, Italy, 11810 kc., 9 a.m. kw.. reported heard 7 -10 a.m., E.S.T. 2:30 39.7 meters, 25.15 meters. Observers to 2 p.m. Also heard on 9635 kc.. (Lawton, McConnan.) says they talk in English and French p.m. to 5 p.m. and 6 -7 p.m., E.S.T. Who is the station on 51 meters that at 4:45 to 5:15 p.m., E.S.T. (Reilly, (Craft, Arickx.) can be heard speaking French every Skatzes, Reichardt.) IQA, Rome, Italy, 14730 kc., heard ETC, Addis Ababa, Ethiopia, re- irregularly. (Jensen, Portman.) ANOTHER KIND OF FISHING ported heard on 25.09 meters. calling Eritrea, 13380 kc., 4 IDU, Asmara, 14t the left is George Ellsworth, Lis- New York at -5:15 p.m. and also heard answering messages. (Port- tening Post Observer for Massachu- 6:30 -7 p.m., E.S.T. (Styles, Nos - man.) setts; at right, his friend, Mr. Lang- worthy.) IRY. Rome, Italy, 16120 kc., talks field with their prize fishing catch of ETD, Addis Ababa. 11960 kc., re- to IDU in Asmara, Eritrea, 8:40 a.m. the season. George also enjoys DX ported heard. (Owen.) (Portman.) fishing and some of these catches he ZE1JR is an amateur station in Salis- RNE, Moscow, U. S. S. R.. 12000 considers just as big as the sail -fish bury, South Rhodesia, often heard kc., Sundays 6 -7 a.m. and 10 -11 pictured. working G5ML in England at 2 p.m., heard E.S.T. He is also on the air at 7:20 a.m., E.S.T. ( Dallal.) p.m., E.S.T. (Wickham.) Asia CR7AA, Lourenco, Marques, is on 49 S. R.. reported meters now instead of its former RIO, Baku. U. S. 84 -meter wavelength. on 10140 kc. and 10170 kc., 6 -8 It is heard heard daily 3 -4 p.m. and on a.m. and at 12:15 a.m., E.S.T. How - Sundays 10 a.m. Reichardt.) to 1 p.m., E.S.T. (McCormick) ald. Portman, Tananarive, Siberia, 4273 kc., FIQA, Madagascar. re- RV15, Khabarovsk, ported back on the air and heard on heard at 3 a.m., broadcasting music. Craft and Cum- 50.45 meters, on the 49 -meter band (Butcher.) Observers from 10 to 11 a.m., E.S.T. (Kruger, mins reported they heard from 1 -11 Adams.) a.m., E.S.T. CQN, \lacao, China. 300 watts, has NORTH AMERICA changed wavelength from 49 meters TFJ, Reykjavik. Iceland. 12235 kc., to 31 meters. They transmit Mondays reported heard 1:40 to 2 p.m., E.S.T. and Fridays 3 -4:30 p.m., E.S.T. (Hen- (Reichardt, Craft, McConnan.) derson, Oliveira.) VE9BK, Vancouver, Canada. re- ZCK, Hong Kong, China, may soon ported heard on 4790 kc., testing at change frequency to 4100 or to 5100 7:30 p.m., E.S.T. (Gallagher.) kc. (Craft.) CNHS, Halifax. N. S., reported JVN, Nazaki, Japan, 20 kw., 10660 heard at 7: p.m., E.S.T. (Adams. Jr.) kc., 28.1 meters, reported heard 12 to Observer Foshay gives call as CHNS. 1 a.m., E.S.T., and JVH on 14600 kc., VE9DN, Drummondville, Quebec. heard at the sanie time. (X. C. Smith, Canada, 6005 kc., 49.5 meters, reported Dodge, Wolf, Dalai, Parker. Torres, heard Saturdays at 11:30 p.m., E.S.T. Kentzel, Davis, Howald, Wilkinson, (Dooley. Evans. Holmgren.) Ortiz, Gallagher. Johnson, Cummins, W3XI, on 17310 kc.. heard at 12:30 Horwath, Pickering.) p.m.. E.S.T., location unknown. JVU, Nazaki, Japan. 5790 kc.. re- (Boord.) ported heard 3 a.m., E.S.T. (Craft.) (Turn to page 562)

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 549

FROM QUAINT OLD TOMORROWS 7 HEADLINES as ONLY the NEW SCOTT Bß/N65 THEM MARCH of a million soldiers breaking bursts fresh upon you, and the joy of being ifiedly guaranteed to outperform any other the untrodden sod of a new empire -peace alive becomes a new and thrilling experience. radio. Then you will know why the in- pacts the newest continental dances ternationally famous SCOTT has been the - - FINEST RECEPTION GUARANTEED death from the air -Olympics-history in overwhelming choice of engineers, broad- the making! It's your world! Get some Enthusiastic letters from the thousands of casters, princes, presidents and celebrated thrills out of it! SCOTT owners all over the world testify musicians in more than 146 countries that no other radio at any price goes so far throughout the world. P- H- Huizen -sends you the news of to complete the enjoyment of a home as I- 30 to the world direct from seething Europe! Get the SCOTT. Once you have felt the in Full Range Hi- Fidelity, it- before it's canned! Broadcast in five 16,000 cycles, bringing you every breath- languages English Dutch French taking overtone of voice and violin, of - - - - Distance saxophone, clar- German - Spanish. Get it direct with a More Verified World trumpet and trombone, SCOTT - with a regularity, a diamond Records Than Any Other Radio inet, oboe and flute, every overtone audible clarity, a magnificent undistorted power and Higher Strictly Class "A" Power-35 watts. to the human ear! Twice the tonal range For undistorted concert volume. 5 times a more beautiful true tone than any other average power. of other high fidelity receivers. radio in the world! Highest Useable Sensitivity -Clearer for- Years ahead of mass production re- eign reception. Less than 1 microvoltsensitivity. ceivers. Strictly custombuilt. Engineered Bullet -Direct Selectivity - continuously COMPARE IT IN YOUR OWN HOME variable 2 to 16 KC -for foreign stations you to the highest precision standards known. have never heard before. 5 -year guarantee. Nationwide installation In the privacy of your own home you sur- Double A. V. C. -keeps world programs round yourself with things you come to at practically even volume. service. 30 -day trial in your own home Short Wave Station Locator -instantly anywhere in U. S. A. cherish-they are an expression of your per- locates foreign stations. sonality. So it is with your radio. When you Tonetruth Chamber -eliminates boom. Send -NOW -for the most thrilling have chucked the cares of business for a Full Range Hi- Fidelity -twice tonal range record breaking perfor- of other high fidelity receivers. 30 to 16,000 story of world- few hours and come home to relax, the cycles. mance in the history of radio! astonishingly small difference in price be- More Important Performance Features whatever. Simply -including True Bass Control, Precision Dial No obligation tween the SCOTT and "just another radio" Calibration, Allwave Reception, Shadow mail the coupon below. vanishes -the very first night you open up Meter Tuning, 23 tubes. the Sensitivity Control and leap through SEND 11115 COUPONTODAY- DETAII5 FREE the tremendous distances of a night charged comparable thrill of its power, once you with the criss- crossing of the million fan- have experienced the glories of symphonic 1E. 0. Scott Radio laboratories,Inc. 4440 Ravenswood Ave., Dept. 5C6, Chicago tastic miracles of radio. You flood your music through its crystal clarity, then and Send "94 PROOFS' of the SCOTT'S su- home with the unbelievable cultures of half only then will you know how it feels to perior tone and DX performance and partic- a hundred nations. The wonder of radio own this magnificent instrument -unqual- ulars of 30 -day home trial anywhere in U. S. A. Name E. H. SCOTT RADIO LABORATORIES, INC. Street 4440 Ravenswood Avenue, Dept. 5C6, Chicago, Illinois When in New York visit our beautiful permanent Salon at 650 Fifth Ave., Rockefeller Center City State

www.americanradiohistory.com 550 RADIO NEWS FOR MARCH, 1936

GERTRUDE BING CROSBY NIESEN

ALICE FAYE

MILTON J. CROSS By Samuel Kaufman ackstage in roadcasting Saturday afternoon broadcasts TIEof full -length operas direct from the "On the Air With Lud Gluskin" the Metropolitan Opera House, series heard the Wednesdays over CBS. New York, are features that music -lovers Since her previous appearances on Gluskin from coast to coast habitually look for- air shows, Miss Niesen has appeared in phone by having a mechanical stooge ward to each year. The National Broad- musical stage productions. named Gadget. Abetting Goldberg, is casting Company is to be congratulated Vera Van, the songstress, and Waldo for arranging to bring these stellar pre- AN unusual repertoire of Latin- Ameri- Mayo's orchestra. The Goldberg feature sentations of the 1936 season to the public can music is presented on the new is heard Tuesdays and Thursdays under despite the fact that they are unsponsored. Sunday afternoon CBS program sponsored the sponsorship of the Schulte Retail NBC stations from New York to Hawaii by the Ford Motor Company. The series Stores. Harry Hirshfield, creator of Abe are conveying the series and, in addition, features Jose Manzanares and his South Kabibble, Desperate Desmond and Home- the programs are offered to the Canadian American Orchestra. The program sup- less Hector, is presented on WEAF, Fri- Broadcasting Commission. Listeners in plements the two other features of the days, with the Fox Fur Trappers, Bir- other parts of the world have the oppor- same sponsor also heard on CBS -the trand Hirsch's orchestra and vocalists con- tunity of hearing America's premier opera Sunday Evening concert hour and the tributing the musical interlude to his troupe via the NBC short wave transmit- Tuesday Fred Waring hour. The Manza- humorous chatter. ters. Milton J. Cross, whom this writer nares unit is composed chiefly of women. rates as the best announcer of musical Manzanares himself and a young singer PHILLIPS LORD, who is a versatile programs, has the narrator's assignment. billed as Dolores do the solo bits. fellow, indeed, has had a bit of diffi- Under the new leadership of Edward John- culty in shaping a commercial program son, the Metropolitan Opera Association NEWSPAPER cartoonists have long that would obtain the equal following of will present many names familiar to air had their fingers in the radio pie. his old Seth Parker features. But he is audiences; among them are Josephine Many of them capitalized on the idea of always coming back with new ideas. Be- Antoine, Helen Oelheim, Hilda Burke, selling rights to dramatizations of their fore his brief "G -Men" series was for- Julius Huehn and Chase Baromeo. comic strips. Now, two of the best known gotten by listeners, he leaped right back creators of pen- and -ink characters -Rube into the program limelight with a series GERTRUDE NIESEN, the radio song- Goldberg and Harry Hirshfield -have of real -life thrills, told on the air by ster now rated as one of the leading come to the air in person. Rube Gold- persons who faced death in strange cir- night club stars, has been reunited with berg, whose crazy cartoon inventions cumstances. The latest Lord idea has her program associate of last year, Lud made funny -page readers guffaw aplenty, been embodied in the Philip Morris pro- Gluskin. She is now featured soloist of has brought the idea to the CBS micro- gram presented over NBC, Tuesdays. Lord AT RIGHT: AT LEFT: SALLY SINGER JOSE MANZANARES

RUBE GOLDBERG AND HIS "STOOGE" LOUIS GRESS

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 o 551 0 s POWER OUTPUT Va.\ 4 * 6 DYNAMIC `GOMPOUND GONOUCTANCE y

CIRCUITS \\3VMUTUAL TRIPLET T

CONDUCTANCE EMISSION

VERA VAN TESTERS

even enlisted the services of a detective agency to search over the world for persons with spine -chilling experiences to narrate on the cigarette program. Leo Reisman and his orchestra, Phil Duey, Sally Singer, the Eton Boys and others in the earlier Philip Morris presentations have been retained to supplement the Lord thrill stories. FTER all these seasons Paul White-

A man has bid adieu . to the Kraft Music Hall feature of NBC. The new permanent star of the Thursday full -hour presentation is none other than Bing Crosby. Prior to the vocalist's taking over full control of the period he was co- The power output circuit by Triplett is Model 1500 tests all types of radio tubes; featured with Whiteman for a month. the last step in Tube Tester Design. glass, metal or glass -metal on the power The Crosby series originates in Holly- output Circuit. Housed in attractive mod- wood. Jimmy Dorsey's This circuit checks all types of tubes orchestra supplies under load, ernistic case with removable cover, suit- the music and a gala array of guest talent approximating actual con- able for portable ditions in a set. or counter use. is presented every week. Bob Burns, who radio Visit your near- Dealer Net Price $36.67 earned a wide following est Triplett jobber and as a comedian see for yourself Model on guest spots has been signed with the how this checker catches those defective 1501, the new Triplett Multi -Pur- show for a long period. pose Tube Tester, combines 10 instruments tubes you had so much difficulty in lo- in one. Housed cating. in same case as 1500. THE talkies of Hollywood continue to Dealer Net Price $46.67 scour the ranks of broadcasting for TRIPLETT new material. The list of radio stars who MANUFACTURES contributed to the offerings of the cinema a complete line of electrical measuring instruments for radio, capital in recent months includes, among electrical and general industrial purposes both standard and others, Jack Benny, Fred Allen, Dave custom built. See them at your jobbers. If you have an Rubinoff, Gladys Swarthout, Lily Pons, electrical instrument problem, write to TRIPLETT. James Melton, Jane Froman and Alice Faye. And still the movie moguls make flattering offers to additional radio names. EMAIL THIS COUPON (Turn to page 569) Triplett Electrical Instrument Company 153 Harmon Drive, Bluffton, Ohio GLADYS SWARTHOUT Please send nie your new 1936 Catalogue Name PACciA.c`on. Address ELECTR9CAL EN5TR UM EUTS City State $/,7 A Perfect

-TURN _:_ $ >CODE TEACHER. -RIGHT- The NEW Master Teleplex The perfect instrument for beginnen, experienced operators, and schoolroom. The new easy way to learn code and speed up wpm. This amazing new instrument will record your own sending on double row perforated paper and repeat it back to you at any speed. 10,000 words can be recorded on one tape. This New Machine Is Remarkable YOU CAST GO No Batteries No Winding All Electric It is the same in principle, and in operation is esual to tho Wheatstone Perforator and Transmitter, which would WRONG WITH A cost over $1,000. Buy It or Rent It Send for Folder RN, 3, which tells you how to get the use of this instrument without buying it. No obligation. We furnish complete course and RIDER MANUAL personal instruction. Low cost. easy terms. Write tion. today for informa- TELEPLEX CO. 72 Cortland+ St. New York City The New Master Teleplex- "The Choice of Those, Who Know"

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 ;5:5°

UP IN A JIFFY AC'Y-JICCff1CY1 5 AT ANY ANGLE RCA RK -40 All -Wave Antenna $5.50 PRIZE CONTEST announcement of awards Zeh Bouck Service Editor

publicizing my radio service, I avail myself FIRST PRIZE of every reasonable form of advertising, There's No Ill Wind with an ad in the local telephone directory It's simple to install. Goes up in a in Rural Radio! as the keynote. In practically all my other few minutes, at any angle, wherever advertising, mention is made -`See our -ad "We are traveling around the country- in the telephone book.' By splurging a bit you can put a 60 -foot straight wire. side making a real go of the new Zenith farm in the directory. I can take less space in main Gets more stations on both broad- radios and the ` Wincharger.' Our my three- times -a -week newspaper ads by and short wave bands. Areally sales talk is the superior `line power' qual- referring readers to my main advertisement. casting fact that that will be especially ity of the receiver itself, and the I find a one -inch, thrice -weekly ad more fine antenna farmer need never worry about his larger display pub- Factory the effective than a much valuable in difficult locations. lished once a week. assembled, all joints soldered. Get TUBES KEN. 7103 "I continually circularize my clientele ACCESORIES with mailing cards and it from your RCA Parts Distributor. DELIVERED and new prospects circulars. This literature is of a nature to steady cus- RCA Mfg. Co., Inc., Camden, N.J. promote good -will- thanking can ROHM for tomers for previous jobs, reminding them A subsidiary of the Super RADIO Repair that the 90 -day guarantee expires, offering RADIO CORPORATION OF AMERICA SERVICE free tube tests, etc. I mimeograph this material, the process being inexpensive, and THIS CARD ENTITLES YOU it is possible to draw in amusing illustra- "TO ONE SERVICE FREC tions. No attempt is made at real art work, but the simple, homely sketches, FIGURE 2 without pretence, do the trick. "I have two types of business cards radio means - battery going dead just when shown in Figures 2 and 3. I distribute the is most dif- the most to him, and when it card in Figure 2 to the proprietors of tav- ficult for him to have it charged in town erns, etc., for the privilege of tacking up -when snow blocks the mountain roads himself and the nearest service between 2967 station. Due to our circulating around WALNUT the farms, we make a lot of contacts which enable us to do business on other than a money basis. If cash is short, but the farmer is willing to trade in a bull that we ERvió7 know we can sell to somebody `down the uu_ line' -why, it's okay with us. In Figure 1 you will find the writer getting acquainted on a complete with the down payment D A V E N P O R T . IOWA new Zenith Wincharger installation!" - Brothers. McCalla FIGURE 3 SECOND PRIZE a similar card, less the free service ad- which latter card is my regular business A Complete Advertising card. Figure 3 is a more ritzy card, and is Campaign printed on a superior linen stock. I use DUAL MIDGET "Advertising, primarily, is a system of this when calling on clients, particularly reminders. Obviously, no single reminder those of the better class. It makes a good can be as effective as several. Hence, in impression with them." -Dave Rohm. Elect rolytics FIGURE 1 Two entirely separate sections in one handy unit. Four leads-two positives, two negatives. Most compact. Unit shown is 8 -8 mfd. 525 T. peak. Compare it with screwdriver. Ideal for crowded assemblies. Or for AC -DC midget set repairs. In 250 and 525 v. peak ratings. Several capacity combinations. Also an 8 -8 -8 unit. Handy mounting flanges.

New 1936 catalog presents most DATA complete line of condensers and resistors. Write for copy and sample of monthly Research Worker.

CORPORATION 78 Washington St. Brooklyn, N. Y.

www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 553 This NEW THIS MONTH'S Type of WINNERS RADIO TRAINING FIRST PRIZE -To McCalla Brothers, Mercer, Pa.- $10.00 for literally taking the bull by the horns (see Figure 1) and making ACTUALLY SETS YOU something out of rural radio! SECOND PRIZE -To Dave UP 111 BUSIHE5S ... Rohm, of Rohm Radio Service, Davenport, Iowa -$5.00 for a complete demonstration of the .... In the Fastest Moving fact that it "pays to advertise "! THIRD PRIZE -To Edwin Lo- Industry in the World ... . vick, Jr., 2502 Harlan Street, Falls City, Nebr. -$4.00 for originality Here, at last, is a NEW and DIF- Nor is that all. Never forget that -the development of sales through FERENT type of Training that not there are too many men of only medi- the organization of school radio only teaches you all phases of Radio ocre ability in ALL lines of business. clubs! Service Engineering work-but which That is why average wages are low - FOURTH PRIZE -To Merril equips you for an actual start in busi- why many men are out of work. Radio Lindley, 2659 Napoleon Street, In- ness. No matter what kind of Radio is no exception. But there is always training you may take, you will require room -there is dianapolis, Ind. -$3.00 for an added such good pay -AT THE service appeals to every materials before you actually are TOP OF THE that cus- ready for LADDER -and this tomer! business. Sprayberry Train- is where Sprayberry Training is spe- ing gives them to you- teaches you to FIFTH PRIZE -To Murl E. cifically designed to put you. It is for work with them men who take Radio seriously -for Beauchamp, Murl's Radio Service, under actual Ser- Muskogee, Oklahoma -$2.00 for those willing to work along sound, in- vice conditions. tensely practical lines to a promoting confidence with a fair - win real and- square guarantee. future in a fascinating industry with vast opportunities for future development. NO PREVIOUS EXPERIENCE REQUIRED THIRD PRIZE -LEARN AT HOME IN SPARE TIME Sprayberry Training is really two courses in Boosting Sales one. Besides the necessary fundamental teaching, a it includes the famous Sprayberry Practical with Radio Club Mechanics of Radio Service formerly said ONLY to men already in Radio -many of whom had "I have recently become a serviceman found their precious training iradegaate for mod- in a town with a population of five thou- ern Radio needs. sand. I have four competitors, all well Sprayberry Training has been honestly, conscientiously developed to fit you for a established and well known. I overcame truly worthwhile place in Radio -a place well above the acreage. It is different from this handicap by organizing a radio club almost any other course you might con- among boys of school and high- school age. sider. It is complete -modern- practical. We have weekly meetings at which some experienced amateur speaks, followed with SERVICE ENGINEERING EQUIPMENT IS YOURS! an open forum. All -wave sets are demon- Upon completion, you have both the strated, and interesting radio experiments knowledge and equipment to enter performed. I encourage set building, business then and there for full or part and time profits -or to start out in any supply used parts at a cost that, while very one of Radio's specialized fields such low and within the as sound, broadcasting, etc. Certainly pocketbook limits of :'nu owe it to your future to investi- the members, assures me a profit on parts -: ate-TODAY I which would otherwise be worthless. There are no dues. Parents occasionally attend these meetings (as do faculty members), SPRAY8ERRY ACADEMY and I have sold several sets through dem- OF RADIO onstrations at the get -togethers, and as a 2548 University PI., N. W., WASHINGTON, D. C. (Turn to page 554) Without cast nr obligation on my part please rush complete details, of your new type of training and the booklet, `MY FUTURE IN RADIO.' (Paste this coupon on postcard and mail today!) NAME AGE

The Service Bench ADDRESS (Continued front page 535) four small nails. Turn the dial to 1500 RN 3-36 kc. Remove the end screw that holds the dial strip. Then raise the dial strip and you will have ready access to the bulb. This eliminates the removal of two knobs, "DEPENDABLE" about a dozen screws and bolts, not to SHUNT - mention tubes. My method takes about ten minutes." 444 Trouble Light and Ground DEPENDABLE YOU WM YOUR OBSOLETE Tester SET RRRLYIER OR SHUNTS & MULTIPLIERS TUBE "One of the handiest (BECHER items in my tool Shunts for all meters in all ranges. Guaranteed ac- kit is diagrammed in Figure 5. Essentially curate within 1% or 2 %. Prices, 2 %n accuracy, 750 it is a trouble lamp- socket, adequate each, net; lßó accuracy. 510 each, net. Ma/tipl)e,s in all standard ranges, accurate within length of cord, on -off switch and plug for 1% or 2 %, 5000 to 10 trillion ohms. 455 to 552.55 inserting into any convenient 115 -volt re- each, net. WRITE FOR OUR PLRR ceptacle. It is invaluable in nosing around KNOBS -service men's assortment of 15, molded the inside of a cabinet without borrowing Bakelite, various diameters, all to fit 14" shaft.. $1.00 MENTION MODEL MODERNIZATION a SWITCHES NUMBER OF YOUR DIVISION couple of piano or floor lamps from the -in au ranges from 3 to 12 points OLD INSTRUMENT or contacts and in single or multi -gang up to 7 gangs. lady of the house. (Folks almost inva- Built for long life and sustained efficiency. riably locate their radios as far as possible Write for Bulletins, from an overhead light source.) Dept. RN -3 Lattada0al "The unusual feature is the third lead, RADIO CITY PRODUCTS CO. APPARATUS CORPORATION (Turn to page 576) 88 Park PI., New York 821 EAST NEW YORK AV., BROOKLYN, N. Y.

www.americanradiohistory.com 554 RADIO NEWS FOR MARCH, 1936 RADIO PHYSICS COURSE ALFRED A. GHIRARDI

Power Power factor, Cos O = -= = .44 Lesson 50. True Z 223.6 Power, P = EXIXCosB = circuit is THE true power in a resistive 110 X .49 X .44 = 24 watts (approx.) Ans. equal to the product of the effective The product of the volts and amperes a volts and effective amperes. In is called the apparent power. Since this reactive circuit, the effective power as apparent power must be multiplied by simply multiplying volts times found by Cos O to find the true or actual power, this amperes, is reduced by the power returned factor is called the power factor of the by the device to the generator, so that circuit. When the current and voltage are the product of effective volts times effective in phase (resistive circuit), the power fac- amperes does not give the true power but tor is equal to 1. This is the maximum gives what is known as the apparent value it can. have, and the circuit is said l0Y power. The true power is given by: to have unity power factor. If induc- P=E XIX Cos O tance or capacitance are present, the power factor will be less than 1. Trouble eats Where O is the angle of lag or lead be- when tween the e.m.f. and current variations, When electrical power is measured by called and cos O is the trigonometric cosine func- means of the electrical instrument Ate' is ob- 6/IIG tion of this angle. The angle O is rep- the "watt- meter," the true power resented in the vector diagrams shown tained directly. When power is measured means of an ammeter and voltmeter in and the customer starts talking in three -letter in (B) and (C) of Figure 1. Diagram by words it's time you got wise to yourself and (B) represents the case of an inductive the circuit, the product of E X I gives the changed to CENTRALAB. Noisy, nerve-teas- ing reception can very often be permanently cured with a dose of "One Centralab Radiohm to one Radio." It works miraculous cures. ,POWER CURVE -B- Try it nest time you're out Trouble Shootin'. E.M. F. and a mere handful service practically any set .\ï I made ... better than ever before. cos 6-'2 irrye ry Radio Semler Man ,illlÌl houidb.amombnof Mt RESISTANCE 1IO1PF 1I!-

ANGLE CURRENT f - OF LAG FI G. 4 Milwaukee. Wis. RADIOHMS Figure 7 Curves of e.m.f., current, and power in a circuit containing capaci- -(a) in an FIXED RESISTORS tance and some resistance. (b) Vector diagram showing angle of lag inductive circuit. (c) Vector diagram showing angle of lead in a condensive circuit.

circuit and that at (C) represents the case apparent watts. This must be multiplied of a condensive circuit. by the power factor (Cos 0) to obtain By trigonometry in either case, Cos B the true watts. is equal to the base divided by the hypot- enuse, or Resistance R Prize Contest Cos 0= _ (Continued from page 553) Z Impedance result of the enthusiasm of the members Therefore: who have carried home the story of supe- Resistance rior performance. Naturally, the club is True power = Apparent power X discussed at home, and it is logical that Impedance the parents turn to me for radio service. Example: "The principal and science instructor of A voltmeter connected across a coil in any school will be glad to cooperate in an a.c. circuit reads 110 volts and an am- the organization of a radio club."-Edwin meter indicates that a current of 10 am- Lovick, Jr. peres is flowing through the coil. The angle of lag is 30 , the corresponding Cos O FOURTH PRIZE being equal to .866. How many watts of power are being consumed by the coil Just Another One of These from the line? Little Things That Count RADIO Solution: "I believe that in order to drum up new P= EXIXCosO =110X 10X.866= service business it takes new ideas. I con- PHYfICr COURJE 952.6 watts. Ans. ceived the plan of offering a complete chas- ByALFREP A. GIi1RAR171 Example: sis cleaning and dial mechanism lubrication 972 pages. Over 500 illustrations What is the true power in a coil having free of charge with every service call. The 856 Review Questions. Price $ 4 a resistance of 200 ohms, a reactance of chassis cleaning appeals to the housewife, an e.m.f. of 110 volts ap- I find that only about one out of ten NM 100 ohms and and FREE CIRCULAREM » its terminals? radios have been so cleaned since the origi- Nim Radio & Technical Publishing Co., plied to 45 Astor Place, New York. Dept. EN -36 Solution: nal installation. $4.00. clean with corn - Please send my copy at Impedance, Z= V R' -I- X? = V 200'+ 100' "The chassis is blown Please send free literature. =223.6 ohms pressed air, and the tuning assembly lubri- NAME E 110 cated with a light oil. The improvement is invariably appreciated. ADDRESS Current, I = -= _ .49 ampere in tuning action Z 223.6 The scheme has definitely brought results." -Merrill Lindley. /. R 100

www.americanradiohistory.com RADIO Ni.ws FOR MARCIr, 1936 555 FIFTH PRIZE Confidence in One's Work Cre- ates Confidence in the Worker F IT'S SOUND "Though many radio servicemen are coming to appreciate the desirability of guaranteeing their work, the idea cannot WEBSTER- CHICAGO be overemphasized until every serviceman follows this practice. My business took an upward swing with the publication of the MAKES IT NOW! A COMPLETE P.A. MODEL P.A. 308 has full 8 Watt undistorted Marl's Radio Service SYSTEM output. It is equipped with 8" dynamic WITH FULL 8 WATT speakers, has OUTPUT fifty feet of extension cord, and Q`tltarantaa Qartifii7Cttz CRYSTAL MICRO- is housed in a strong leatherette covered case. PHONE SINGLE Fully portable, net weight with single speaker OR DUAL 27 lbs. SPEAKERS MIXES MICRO- U.\ TE...... SEI'...... Model P.A. 308 is also available for fixed in- service royal, PHONE AND PHONOGRAPH deibscredd i n below stallations. System is oai oeois° ntebt MU . complete, speaker fur- E. BEAVCFIAMP, the undcrslgned, fori recluti t nished with ch'ars'have baffle. been paid indf ll. work done If nai` trouble in ditions con- during the tiundere imit se[ y tills guarantee Input is provided for tt Mpartseses to crystal microphone sup- placeefrec of charge 'previously' or ed not replaced n plied and for are t subject °to rguarantor. ñ high impedance phonograph servire and Charges. covered by Guarantee (Webster Model 1252). Individual microphone and phonographing PARTS...... _...... mixing controls. Tone E...._.... _..._- -- control, mixing controls and On -Off switch located on front panel.

Price is surprisingly TOTAt. low Write for details FIGURE 4 WEBSTER COMPANY Section M6 following advertisement in the local papers 3825 W. Lake St. -'Guaranteed radio service work at rea- Model P.A. 308 Chicago, Ill. sonable prices. A guarantee certificate Please send me frill de- given with each radio repair or installation. tails on Model PA 308... WEBSTER- CHICAGO Send complete accessory Murl's Radio Service stands back of their catalogue workmanship and materials. Phone 2090 manufactures a complete line of Name for a prompt response.' A copy of my public address systems, sound guarantee certificate is shown in Figure 4." Address -Hurl B. Beauchamp. equipment amplifiers and accessories of all kinds. City State J Output Meters (Continued from page 533) screen and only its thin edge intercepts the beam. 'flats the dark area decreases until only a thin line is visible. The circuit of the Weston moving coil, copper - oxide rectifier type of output meter is shown in Figure 3. The sensitivity of this type is such that it may be used directly across voice coils. Since a series condenser is supplied, it may also be connected from the plate of an output tube to ground, or across the plates of push -pull output tubes. For aligning, the last method of connection will require the lowest signal voltage but is not always the most convenient way to hook up an output meter. For power output measurement, it has a constant impedance of 4,000 ohms. It is not generally realized that a d.c. mil - lianteter may be used as an output meter with any set having a.v.e. A method of connecting same is shown in Figure 4. A meter giving a full scale deflection for S milliamperes may be used for most r.f. or i.f. amplifier tubes. Or, if desired, a tore sensitive meter may be employed MADE OF ISOLANTITE- UNAFFECTED BY in conjunction with :t variable shunt. This is L O W E S TEMPERATURE OR likewise an ideal outing meter. Its use in this T L O S S E S connection was described in the October 1935 O H U M I D I T Y issue of this magazine in an article on the Bat- tery operated Super. In operation, with no signal being received, the meter indicates the plate current of the tube with its fixed grid bias. When SIDE SUB PANEL a signal is received additional grid bias is OR BASE plied' sup- GRIPPING CONTACTS through the a.v,e. system, decreasing the - M O U N T I N G -TUBE plate current reading on the meter. When the RUST PROOFED LOCATING GROOVE- receiver is properly aligned the signal reaching D the detector is a maximum and likewise the a.v.e. voltage. is a maximum. 'therefore when the tuned circuits have been no adjusted that the plate current reading has reached its minimum value with CONSTANT RESISTIVITY a - given signal input, the alignment is correct. MAXIMUM 4, 5, 6, AND 7 PRONGS This type of receiver adjustment procedure is EFFICIENCY recommended by the manufacturer of at least O One high -fidelity receiver. Since only the carrier wave is required, the test signal need not he modulated. Likewise, a broadcast signal be used. may Write for FREE NEW CATALOG RN -3 In detector systems not of Condensers, Transformers, employing diodes, Chokes, Sockets, Coils and data on re- whether or not a.v.e. is used, a d.c. niillianteter ceiving and transmitting equipment. may be used as an output meter by connecting saute in series Attach IOc for 32 -page Manual of most with the cathode resistor, or a 3m 8a-fish Tdatli popular Short -Wave Receivers, with illus- high resistance voltmeter may be connected across trations, diagrams and parts lists. the bias resistor. With plate detection, the meter ,l-pmmärlund reading will increase with an increase of signal s.ofv input- With grid detection, the meter may PRODUCTS placed in he i i the plate circuit. The reading will de- Hammarlund Manufacturing crease with an increase in signal voltage. Co. 424 -438 W. 33rd Sf., New York

www.americanradiohistory.com MARCH, 1936 556 RADIO NEWS FOR It's Taken The Radio World By STORM

the 1936 SUPER SHORT-WAVE PAGE SKYRIDER MANY years ago when we first became interested in short -wave radio, people of this international hobby better relation- WEWJ E knew the 1936 Super told us that through the medium v Skyrider was good, but ship between the nations could be accomplished. Is this correct? In some cases the avalanche of enthusiastic ap- the answer is yes, but in the majority we cannot see that any belligerent feel- proval has overwhelmed us. ings have been forgotten or put to one side because of short waves. Dealers and Hams, from all parts of the country have joined SHORT -WAVE listeners have a splendid Coast works a station on the West Coast in a chorus of unqualified praise. opportunity to broaden their views on on this band it is considered very good DX. topical events by listening to the news The majority of these coast -to -coast con- No wonder. The Super Sky - is known as bulletins from short -wave broadcasting sta- tacts are established by what rider is modern. We've elimi- "networks." Several amateurs operating makeshift tions. One can take the English versions nated the clumsy, European controversy and on or about the same frequencies "gang plug -in coils and substituted an of the present of a then tune to Rome and hear just what up" and operate under the guidance up -to -date band switching sys- the Ethio- "key station." If it is an East Coast We've put all its parts, they have to say. Providing tem. pian stations are active, it is not difficult group trying to work "West," they try to speaker, power pack, everything stations and hear the round up one station after the other until in one compact cabinet. to tune in the "E" war news direct from the "front," as it they have cleared a channel from coast to coast. Complete cooperation is the The Super Skyrider is sensi- were. of in- matters of world -wide interest, motto ! When you have an attack tive beyond all practical require- Other their Core such as the seemingly forgotten war debt, somnia, listen to these boys "work" ments with its new Iron outfits to their full I F system. And it's engineered the armament conference and employment fairly low- powered to take full advantage of the conditions, are discussed through the outlet extent. -wave transmissions. But all this Another band assigned to the amateurs improved characteristics of the of short admit that our new metal tubes. does not, in our opinion, "solder" the nais 40 meters. We blandly tions together any closer. But the truest, more than limited knowledge of code But in spite of all its advan- strongest and most lasting relationship has forces us to say that 40 meters is a closed tages and its superior Halli- been established by the amateurs. Many "book" to us. crafters' engineering -the Super fans have asked me "what is From there we will go to 75- and the short -wave frequencies Skyrider is extremely moderate an amateur." For the benefit of these 20 -meter bands. The exact in price. Don't fail to see it at readers we will quote from the "Rules are 3900 to 4000 kc. and 14.150 to 14,250 your jobber's today! Or write and Regulations" governing amateur radio .kc., respectively. Both bands are used information. term amateur radio oper- exclusively for phone and c.w. operations. for full stations. "The not ator means a person holding a valid li- The former has DX possibilities but cense issued by the Federal Communica- as great as the latter. Neither of these tions Commission who is authorized under bands are allowed to be used except by the regulations to operate amateur radio holders of a Class A license. This license is issued after an amateur has held a -V Southport Ave., Chicago stations." 3001 Amateur radio communications are solely Class B ticket for one year or more and Cable Address "LIKEX" New York with a personal aim and without pecuniary then he must undergo another examina- interest. This last rule, which is strictly tion. adhered to by the amateurs, causes the To continue with our tale of what can frequencies. The 14- "HAM" SPECIAL e;d majority of the amateur communications be heard on these ray is of the most A highly efficient code teach- to arouse the interest of the short -wave meg. amateur band one er using heavy specially pre- on the ether channels. Here are pared waxed paper tape. listeners. The "programs" are of a spon- interesting having two rows of perfora- music is rarely just a few of the amateurs that we have tions. Write for Free folder' R.R.3" taneous nature and although DEALERS Correspondence in- bands, heard. vited with -dealers for protected heard on the American amateur terrrtories. every conceivable topic is brought up and VO1I, St. Johns, Newfoundland, has his We are the originators of located three miles away from this type instrument discussed in detail. transmitter Instrument with tapes prepared of operation. The transmitter by expert and complete course TELEPLEX CO. The short -wave listener cannot partici- the point of lessons: all for $11.95 72 CortlandtSt., Newyork City pate in the discussions, but we certainly is operated by remote control and five can listen in to the "pros" and "cons" as miles of telephone or land wire are involved they waft their way across the ether to us. in this clever idea. Let us listen together to these amateur TI2EA, San Jose, Costa Rica, is operated bands and see what there really is to hear! by a soft -spoken gentleman who says that SERVICEMEN The frequency that the average amateur he has never been away from his home on when he gets his first license town but learned all his English from the by the demand operates speaking Profit by is between 1800 to 2000 kc. There he can radio and by talking to English- Group ' for TRIMM Group "work" on voice and make personal con- amateurs. Hearing Aid Equipment tacts. If the licensee is "sold" on code he ON4CSL, Kasai, Belgian Congo, has been on missionary TRIMM RADIO MFG. CO. is permitted to operate on various other in that portion of the world III. The 1770 W. Berteau Ave., Chicago, bands. If an amateur living on the East duty for over twenty years. operator,

www.americanradiohistory.com RADIO NEws FOR MARCH, 1936 557

Carroll Stegall, contacts the United States every week, and keeps abreast the times by this means. Mail from Kasai goes by "native runner" over a great distance and it takes several months for a letter to reach him, whereas by amateur radio it is only a matter of a few seconds for him to hear all the news from home. Then you may hear CO2AU, Cuba; K4SA working ZL1AR, New Zealand, who was on 7 meg.; HI5X, Santo Domingo; HKIZ, Colombia; VK2UP calling HI5X; VP2CD, St. Johns, Antiqua, asking a New York amateur to find out why his QSL cards had not arrived; G5ML, England, complaining that a New York amateur's signals were "washing out" his reception of an English amateur; VU7FY, India, informing HI7G that he was receiving him 100 percent; HI7G complaining that OM, VU7FY did not hear him; XS2A, South Africa, talking to a "W4" and informing him that the South African amateur would be transmitting on 10 meters very shortly and would appreciate reports. SERVICE MAN lflt&St KNOW! When listening to the American ama- Yes, believe it or teurs it is not, a service man tered. A few of them are listed below. extremely interesting to hear the today must have at his various and absolutely different instant command The rest of the 417 are tabulated on a pronuncia- 417 different kinds of data in tions of words that are used in our every- order to check-sheet which we'll be glad to send do his work successfully and hold his you free. day conversation. It is a simple matter own against competition. to distinguish between the New England, How Southern many of these things do you Just ask for it by mailing the coupon. and the Western amateur once really know? Be honest you hear them talk. All continents can be with yourself It'll help you check up on your present -just take out a pencil now heard within a short length of time if you and put store of radio information -the equip- down on paper a list of all the different ment most indispensable in your busi- tune carefully on this band. But remem- things you are confident ber that the foreign amateur generally op- you've mas- ness. erates higher or lower in frequency than the American amateur or on what is known Here are just a few of the 417 as "outside" the American band. We are really pleased at the tremendous 1. TEST INSTRUMENTS 11. CASE HISTORIES amount of interest displayed by short -wave All about the latest commercial models of all kinds. All progressive service men keep and use "Case Ilis- listeners See pages 5 to 42:1 in MODERN RADIO SER- tories" of receivers to speed up their work. towards the amateurs. Thousands VICING, which will also tell you how to build your In the Supplement book you'll find the actual trouble of fans send reports of real value to ama- own, if you-wish tn. This section could make a com- Symptoms and Remedies for 7,70 common ,American plete book in itself! receivers! teur stations ; in fact, one station that we know receives 700 short -wave listeners' re- 2. LATEST TEST METHODS 12. AUTO REFERENCE DATA ports a month. The majority of the ama- Test procedures that have proved most successful with You have to know where to find all kinds of special the teurs "QSL" or verify such reports when best servicing organizations in the country. . ignition -circuit adjustment data for auto-radio work. In MODERN RADIO return postage is enclosed. But surely no SERVICING there are 121 It's all conveniently assembled in MODERN pages, illustrated, that give you all of therm. RADIO SERVICING's Supplement-for all cars! one could expect anyone to answer a letter and send a verification card (that costs 3. LATEST REPAIR METHODS How well do you know these? money) without postage enclosed. Remem- Real time-saving methods for making every kind of radio repair. . . . They're all explained and illus- ber that amateur stations are all operated trated in MODERN RADIO SERVICING! How many more do you know? at the sole expense of the amateur and all 4. AVC AND QAVC SEND FOR THE CHECK -SHEET available cash is generally put into parts CIRCUITS OF 417 THINGS EVERY or supplies to improve the transmitting All their characteristics, peculiarities and troubles. SERVICE . See pages 441 to 491 in MODERN RADIO MAN MUST KNOW and receiving equipment. Gone is the day SERVICING. when an amateur literally threw a few And don't forget -you'll find "junky" parts together and called 5. INTERMITTENT RECEPTION, HUM, it a DISTORTION complete information about receiver. Now the best is not too good These and other obscure. hard -to -crack troubles, such every one of them for the amateur who values his reputation as Oscillation, Double -Spot Tuning, and Fading, you in- highly. must know how to identify and repair.... MODERN RADIO SERVICING gives practical information on all these and many more. MODERN RADIO

6. ALIGNING RECEIVERS -THE CATHODE - Electron Tubes RAY OSCILLOSCOPE SERVICING (Continued from page 523) You can't afford to let any T -R -F or superhet alignment job baffle you. . You can crack the hardest cases when you apply the dope in MODERN RADIO By Alfred A. Ghirardi magnetic pick -up of an electric phono- SERVICING, which also tells you all about how to graph provided the energizing impulses, use the Cathode -Ray Oscilloscope in your work. 1300 Pages. 706 Illustrations. and the light thus generated, fluctuating 7. AUTO -RADIO 723 Review Questions. in accordance with the recorded music, A whole science in itself, which you need to know Together with 240 -page was focussed on the photo -electric ele- from A to Z. . Yes. it's all in that book, 1110D- ment of the new tube which converted it ERN RADIO SERVICING -every phase of it! RADIO FIELD SERVICE DATA into Supplement electrical energy and amplified it 8. NOISE AND INTERFERENCE greatly. Output of 2 to 3 watts, for the One of the biggest bugaboos of all service men. You $5.00 direct operation of the loudspeaker can't know too much about how to track down and eliminate kinds of through which the music was heard, was all noise and interference. . . obtained. Such great amplification through MODERN RADIO SIiRVICPNG gives you 129 pages cram full of hard facts. RADIO & TECHNICAL PUBL. CO. a single tube can be accomplished at an 45 Astor Place, N. Y. C., Dept. RN -36 extremely low noise -level. 9. SALES AND ADVERTISING Please send your Introductory Com- bination Offer of both books at $5. Mr. Farnsworth's tube, described at What good is all your knowledge if you don't know (Foreign $5.50.) how to sell your ? Washington, is called the "Multipactor," service You have to be a good Please send free descriptive literature. business man as well as a good servire man. . Please send the TTtE7. CI IECK -LIST the television expert giving it that name There's a whole chapter in MODERN RADIO of 917 Things Every Service Man because the amplification attained is due SERVICING that tells you exactly how to go about Should Know. building up your business and making care money. to successive impacts of a stream of elec- NAME trons on specially treated surfaces within 10. INTERMEDIATE FREQUENCIES ADDRESS the valve. He declared that electron multi- You must have an extensive list of i -f's if you do pliers have been made to perform every any alignment work. . . . MODERN RADIO OCCUPATION SERVICING's Supplement gives you the i -l's for What kind of information do you need function now performed by the ther- 5,400 different euperhetsl - most t D Test instruments? Newest mionic test methods? ID Sales and advertising? relay. Case histories? Repair methods? (Turn to page 569)

www.americanradiohistory.com 558 RADIO NEWS FOR MARCH, 1936

INow-a high-powered-

Radio Engineering Library -especially selected by radio specialists 41 THE TECHNICAL REVIEW /McGraw-Hillraw -Hill publications CONDUCTED BY ROBERT HERTZBERG to give most complete, dependable coverage of- facts needed by all whose fields are grounded on radio fundamentals on receiver -available at a special price and terms. The Cathode -ray Tube at Work, by receiver circuit design and one F. construction. Here the reader will find These books cover circuit phenomena. tube theory, net- John F. Rider; published by John works. measurements, and other subjects -give specialized Rider, 1935. A book for servicemen and the problems of receiver design and de- treatment of all fields of practical design and application. of receivers from the simplest They are books of recognized position in the literature - others who wish to use the cathode -ray scriptions and be referred to often. If you are design, opera- books you will refer to field oscillograph. It is a reference book which to the largest. Transmitter practical designer, researcher or engineer in any in a similar based on radio you want these books for the help they explains the principles of the tube and its tion and building is described give hundreds problems throughout the whole field vein which takes five chapters. Ultra- short- of In engireeslnf associated equipment, describes the available commercial models, and gives detailed wave equipment, power supplies, antennas 5 volumes, 2482 pages, 2000 illustrations information on the practical applications, -are some of the other subjects. Included 1. Everitt's COMMUNICATION ENGINEERING to perform the experiments and how are also numerous tables, charts and chap- ENGINEERING how 2. Termen's RADIO to interpret the results. Mr. Rider's text ters on operating a station. 3. Chaffee's THEORY OF THERMIONIC by R. T. Beatty, VACUUM TUBES will be easily understood by the average Radio Data Charts, & Sons, 4. Hund's HIGH- FREQUENCY MEASURE- More advanced readers may second edition, published by Iliffe MENTS serviceman. a little weary of some of his lengthy London. This is a collection of alignment 5. Henney's RADIO ENGINEERING HAND- grow appeared in BOOK and detailed explanations, but others need charts which have previously 30 of these them. The practical applications have The Wireless World. There are 10 days' examination. Special price. Monthly payments. explanations on how to use 326.00 worth of books cost you only $23.50 under this been discussed in sufficient detail to be charts with is them, solving many of the equations often smallAddonthly installments, while youuusebthbooks. y readily understood. The book profusely with reproductions of the employed in radio engineering. The charts illustrated insure reason- r traces obtained on the screen. are of a large enough size to COUPON covered begin SEND THIS ON-APPROVAL The opening chapter deals with the tube able accuracy. The subjects Book Co., Inc. frequency McGraw -Hill Here the operation of the tube is with such simple conversions as 330 W. 42nd St., New York, N. Y. itself. to ratio, and Radio Engineering Librnry, 5 vole., f 10 days' nomi- tubes to wavelength, decibels power- Send me plus few ceinte described and data on commercial nation o 55,000'. In 10 days I nd t2.5Ó. circuit design, ellpaid. is followed by a chapter include charts for tuned en.rmiittancbooks t install- are given. This (Weeny geomonthly ere accompannied reactances of coils, Ohm's Law, resistances ment) t on sweep circuits. Chapter III deals with design of pads, design of Name a.c. voltages on both sets of plates, show- in parallel, power- transformers, and others. Address ing the development of Lissajous' figure. Sound Amplifier Circuits, a 24 -page book City and State Another chapter describes the commercial published by The Standard Transformer Position cathode -ray oscillographs now available. RN 3 Ill., contains tech- Company -35 of the Corporation, Chicago, This is followed by applications amplifier cir- to servicing receivers and nical data on a dozen audio oscillograph in output from three to thirty amplifiers. The use of the equipment for cuits ranging curves takes watts. Various tube combinations have the observation of resonance of a chapter by itself. The different been selected, showing the possibility NEW BUSINESS HELP a whole between high quality and low systems used and their mode of operation compromise are discussed exhaustively. It is also pos- cost. sweep out the Complete parts values are given in every FOR sible to have the tube illustrated have SERVICEMEN! frequency characteristic of a re- case. All the amplifiers overall actually been built and thoroughly tested, or amplifier ; this subject is also Do your own ad- ceiver who follows the diagrams and in a separate chapter. Auto - and the builder vertising described good parts is assured of good printing. Boost radio vibrator testing, transmitter adjust- and uses business 10% to results. 50% for a few ment and miscellaneous applications com- cents weekly! plete the volume. The Radio Amateur's Handbook, 1936 Review of Articles Appearing Edition; published by the American Radio 1935, Issue of Relay League. This famous Handbook in the December, has grown considerably since the previous the Proceedings of the Institute GET A edition. The number of editorial pages is of Radio Engineers $2750 now approximately 380. The title already indicates that it is a handbook for the Automatic Selectivity Control, by G. L. ROTOSPEED amateur, telling him what he needs to Beers. A receiving system is described in cáÌÌ suppheSk know of the theory of radio and giving which the selectivity varies automatically DUPLICATING PRINTER This effect is obtained With a Rotoepeed you n cut costs and increase business at the sa constructional data on transmitters and with the sensitivity. time. Do your own print ins-invoices, letterhead statements. receipts the use of several triodes whose sto. Do your own advertising- oarde, letters. handbills, offering specials receivers for short -waves and ultra -short through Reproduce ANYTH NG- writing. typing guarantee ert.Scaios, etc. cathode impedance is shunted drawing-do it quickly simply, easily and at am zing savings. waves. The additional space is largely plate -to- write rer details egarding it. extended treatment of across a number of the receiver's tuned TRIAL OFFER Al des ip ive li eirth'rgg nd fact devoted to a more business with o Itotoepeed. "a.s.c ", employed on hew other building antennas and to ultra- shortwave equip- circuits. The abbreviation St. in this paper, will un- The ROTOSPEED CO. 34 Dayton, Ohio ment. for the first time chapters dealing with the theory doubtedly come into common use. The Operating of radio are more in the nature of a review Photoradio Apparatus and cover their ground rather Technique Improvements, by J. L. Calla- since they An quickly. The chapter on tubes, besides han, J. N. Whitaker and Henry Shore. of typical tube cir- interesting and complete description of CO containing descriptions Buy at factory prices. 30 models methods as success- choose from. AC-D All-wase, includes a complete table of tube half -tone transmission Farm, CarC and Metal T u model. cuits, prac- Send postcard for NEW 1936 Bargain with socket connection fully employed today in commercial Catalog FREE. Gee detail. of 30 characteristics in the TRIAL Agent- This list contains both receiving tice. While television languishes proposition. Also oak for at NEW diagrams. is an established .r

~~www.americanradiohistory.com RADIO NEWS FOR MAucir, 1936 559~~

Notes on Intermediate Frequency Trans- Catalog of Radio Parts former Design, by F. H. Scheer. Receiver The new 1936 catalog of Bud Radio, Inc., is a design engineers will find this paper of 20 -page affair, listing an unusually large assort- value. ment of radio parts and accessories for all pur- "I'M It describes a method of determin- poses. SURE ing coil A good book for radio amateurs, experi- or condenser merit, the more mentors and service men. Copies may be had usual types of i.f. transformer assemblies, free from RADto News, 461 Eighth Avenue, formulas for predicting gain and selec- New York, N. Y. SOLD ON THIS tivity and a method of obtaining high fidelity. NEW SYLVANIA The Ionosphere, Skip Distances of Radio Y9Ib iVaves and the Propagation of Micro- ! iPI1PIII1 2 Edition waves, by E. O. Hulburt. From k,. BOOK" ionosphere Dependable data gathered by the Bureau of Standards ' and associated scientific organizations, the -RADIO skip distances of radio waves are calcu- DEVICES lated for temperature and tropical zones, Soientific.oily with the diurnal and seasonal changes. Produced Theory indicates that the observed bend- ing of microwaves over the horizon is BU'D:'IVA brp R::'Cteexfx.d:f;: RaDIOSßIyRE(Oi due to diffraction of the waves over the WHOU.ISiui_.u..k;ur"...,."" bulge of the earth and to temperature gradients in the lower atmosphere. Ultra -Short -Wave Propagation Over Amateur Catalog Land, by C. R. Burrows, Alfred Decino A new 63 -page catalog devoted exclusively to amateur radio equipment has just been issued by and L. E. Hunt. In this paper an ap- Wholesale Radio Service Co., Inc. This includes proximate theory of short -wave propaga- the first available information on a number of tion over land is propounded, and various new receivers and transmitters, and also a technical "editorial" section containing data for ama- formulas involved the antenna height, the teur operators. Copies are available free of wavelength and the received field are charge to amateurs from RADIO NEWS, 461 given. Eighth Avenue, New York, N. Y. A Quantitative Study of the Dynatron. Tube Tester Booklet by F. M. Gager and J. B. Russell. This The Evolution of Tube Testing is a booklet paper describes two methods of predicting published by the Supreme Instrument Company and describing their Model 59 Standard and De the performance of a dynatron oscillator. Luxe tube testers. It includes circuits and discussion of the methods used for testing the qual- Review of Contemporary Literature SEND FOR YOUR Waveform Errors in the Measurement of FREE COPY OF Pozerer Transformer Losses. General Radio Ex- perimenter, November, 1935. A method of de- SERVICE HINTS termining these losses, which are held to be im- TODAY. IT MAKES THE portant, is described for the benefit of communications engineers. TOUGH JOBS EASY. An Improved Carrier- Interference Eliminator, by W. Baggally. The Wireless Engineer, De- Service men all over the country tell us they cember, 1935. (London.) Technical details of a ouldn't be without this new volume of Syl- circuit that eliminates carrier "whistles" with- vania Service Hints. It helps them out of lots out interfering with the reproduction of frequencies both above and below the whistle fre- of tough spots, because it was actually written quency. with their problems in mind! ity of tubes, detecting leakage with a neon Iamp, Ca'hode -Ray Technique Abroad, by Bernard and providing a circuit which will test all glass Successful service men . . . men who lcnow IL Porter. Radio Engineering, December, 1935. and metal tubes with but five sockets and no radio and are on the job every day wrote The achievements of various adapters. ... foreign laboratories The special features of the De Luxe this book. They sent in their solutions to hard - in the cathode-ray field are discussed in this model are also described. Readers can obtain a to -crack problems . article, and various departures from American copy of this booklet by addressing their requests .. and Sylvania just com- practices are described. to RADio NEWS, 461 Eighth Ave., New York piled these solutions into Service Hints ", Propagation of Ultra -Short Waves, by Charles City. Volume 2. R. Burrows. Bell Laboratories Record, Decem- In this new book you'll find answers to ques- ber, 1935. This well- written article Radio News Booklet Offers Repeated embodies the tions that may have been bothering you . . results of numerous experiments on the ultra- For the benefit of our new readers, we are hundreds of short cuts that practical short waves made by engineers of the Bell Labs. repeating below a list of valuable technical book- service men have discovered . . and is of special value to amateurs who are in- lets and manufacturers' catalog offers, which for themselves . up- vestigating the five -meter band and the still were described in detail in the August, Sep- to -date tips on circuit and receiver troubles. shorter ones. tember, October, November, December, 1935 and Don't wait. Mail the coupon below for your Transmitters for Ten Meters, January and February, 1936, issues. The ma- by George jority copy of Sylvania SERVICE HINTS today. Grammer. QST, January, 1936. The amateur of these booklets are still available to our This up -to- the -minute information 10 -meter band has been more or less a neglected readers free of cost. Simply ask for them by may put orphan, but interest in it is developing quickly. their code designations and send your requests to you in line for jobs you didn't know you could RADIO The author describes several simple transmitters NEWS, 461 Figlith Avenue, New York, do! Clip the coupon now . you'll receive for this band and points out some of the pe- N. Y. The list follows: your copy of SERVICE HINTS in a few culiarities of 10 -meter operation. S1- Analyzer booklet, published by Supreme days. Instruments Corp. The Detector Input Circuit, by W. T. Cocking, Free. The S2- Transformer bulletins, issued by Kenyon Hygrade Sylvania Corporation. Makers of Syl- Wireless Engineer (London), November, Transformer Co. Free. vania Radio Tubes 1935. The practice of operating a diode detec- and Hygrade Lamps. Fac- large S3- Bulletin of sound equipment, issued by tories of Emporium, Pa., Salem, Mass., and St. tor with inputs is receiving considerable Sound Systems, Inc. Free. Mary's, Pa. attention. The author discusses various circuit arrangements and pays particular 84- Amateur equipment catalog of 'Wholesale attention to Radio Service Co., Inc. Free. the input connections. The All- Around 14 Mega- cycle Signal Squirter, 01-Dial Bulletins, issued by Crowe Name by M. P. Mims, QST, Plate E Mfg. Co. Free. December, 1935. Details of a rotatable, direc- 02- Carbon Resistor folder, published by SYLVANIA tional amateur antenna, somewhat fearsome in Ohio THE SET -TESTED RADIO appearance but providing decided advantages Carbon Co. Free. TUBE to 03-Mote- Catalog of "Candolmt" wire- 1936 the advanced "ham". Oscillators Using 14 Hygrade Sylvania Corp. Megacycle Quartz Crystals, wound resistors. Free. by J. M. Wolfskill. 04- Cardwell condenser catalog. Free. QST, December, 1935. A dependable 20 -meter NI- Resistors folders, Hygrade Sylvania Corporation crystal has long been wanted by amateurs. It issued by Erie Resistor Corporation. Free. Emporium, Pa. RN 3 is available at last as the results of some recent N2- Latest resistor development work by the author. catalog of Ehrenrad, Inc. Please send me free, without obligation, Volume 2 Free. of Sylvania's "Service Hints ". Functions of C and R in A.V.C. Circuits. The N3- Folder on resistance bridge, issued by the Experimenter Amateur Call Acrvox Research Worker, October, 1935. A \Itimer Company. Free. Serviceman clearly Emphpvd by dealer 0 written, easily understood explanation .1N1 -Free code charts, offered by Dodge's In- Iadcpeullcnl D of a.v.e. circuits and how they work. stitute. Free. D1-- Yaxley Replacement Manual. Free to Member Service Organization servicemen and dealers, only. Free Bulletins D2- Latest Sound Equipment Bulletin NAME Webster of Catalog of Sound Co. Free. Equipment D3- Catalog of Resistors and Condensers, of ADDRESS A 16 -page booklet listing public the Aerovox Co. Free. -address sys- 134 tems, microphones, loudspeakers, tubes, and other -Free booklet on servicing instruments, CITY STATE parts and accessories for "sound" work. A gnarl Rachio Products Co. catalog for the P.A. specialists, J1 -1036 Allied Radio Corp. Catalog -114 brought out by pages NAME OF JOBBEIL Inter -World Trading Corp. Copies may be ob- listing radio receivers, service and ama- tained free of charge from R.soio News, teurs' parts, P.A. equipment, etc. Free. Eighth 461 ADDRESS Avenue, New York, N. Y. (Turn to page 575)

~~www.americanradiohistory.com 1~~

~~MARCH, 1936 560 RADIO NEWS FOR~~

~~OVER 310 TUBE TYPES~~

~~To FT~~

PGreatest compact pocket size com- ORD? QRD? ORD? pilation of vital radio tube information in the industry! CONDUCTED BY GY If you are e National Union radio 1 tube dealer role your distributor for a free copy. If you are not a National Union tube ' ZO dealer, send ten cents (stamps or coin) to cover postage and handling OR THE life of a columnist is indeed hard, for there are times when he must coupon asking for name of hurt those he actually and impartially likes. But 3Sendnearest National Union distributor print news which might from whom you can get e copy free. the motto is "hew to the line and let the chips fall where they may." MI t- W NM I- MIN 0 MI e\ NATIONAL UNION RADIO CORP. of N. Y very beginning of the organizing the credit to the one who deserved it. 570 Lexington Avenue, New York, N. Y. the and and solidifying of the American Radio Sometimes the IBEW was condemned Who is my nearest N. U. jobber? INTelegraphists Association, every parcel at other times lauded for their various RN336 from those dinky maneuvers to get operators to enroll with Name ' of news that came forth headquarters in the basement of the hotel them. For the same reason was the ARTA I case might have Street on Irving Place, New York, was given out berated or extolled, as the State unadulterated and without been. We aided the ARTA because we `City to the members, knew J any special dressing to brighten it up. believed in one man and because we Truth and straightforwardness was the that if this man were left alone to direct watchword at that time. There was an the destinies of the organization, it would of camaraderie and shoulder -tobe done honestly without any personal Every Job's a SNAP./ attitude went to such shoulder action which brought out the best emoluments or profit. We one. Every thought and extents that some of our fan mail remarked that was in each fathering the effort was pressed toward an ultimate goal. that perhaps we might be . . . this column That goal of unity of an entire professional organization. But today Radio Operating, was "one for all and ye editor are only given the news that industry, At the and all for one," "for, by and of radio- they seem to think is fit to print. men." last meeting of the National Convention of The picture has now changed. From the the delegates of the organization Ye Editor offices of the basement it has elevated itself to a nice was, at the time, in the in rooms that are light and president of the ARTA and was not in- office building it airy. But a change has taken place in the vited to sit in with the delegates. Was was some news that might °I USE ALLIED SERVICE EQUIPMENT" faces of the men sitting about reading or because there There isn't that attitude of leak out to the proletariat which might playing. or "This one looked like a terror -but it turned thought, of action, of intense building. not be good for their digestive organs out to be a set -up. The toughest job in the Perhaps it is that the basic foundation of was it because secret meetings must be world can't faze me when I use ALLIED who kept from prying eyes and ears? Regard- Service Equipment. My customers like the the organization is not there, the man way I locate haywire spots in a hurry. I give planned everything, who, with his own less of the reason, this was very bad taste. them speedy repair service because short -cut hands, dug the first ditches. There are This column was the first means to in- methods are every day stuff to me. My repu- of of the organi- Equipment some men there who do not even know form the nation radiomen tation is built on ALLIED Test and of its various moves and and on ALLIED parts. That's why I say - him personally. Is it because he's grown zation every job is a snap when you've got reach him or is it thoughts. At that time ye editor printed you." so big that they cannot ALLIED behind he has removed himself from their all the news, whether for or against. It 1936 Catalog. Dept. M. because Send fbr Free midst? Perhaps this latter is the truth, came direct from its source. But today it because he has taken other offices in an- must first be scrutinized by advisers before ALLIED RADIO other part of the building. There isn't real it is given out. Whether this meets with W. JACKSON BLVD. honest news or info forthcoming; there are the radio ops' approval or whether it will 833 of denunciations upon those CHICAGO, ILLINOIS only rumors and gossip. Shall we print bring a flood only that news which we believe to be responsible will be seen later on. good for the men to know, or shall they The illustration in our heading this the new hydrophone equip- The NR know everything truthfully and so help in month pictures of strength ment developed and installed on the survey EXPLORER "Rebroadcaster" keeping that solid foundation help from "one for all and all for ship Pioneer to rechart the ocean depths Radio an All- Purpose Amplifying System! and Makes Any is the life blood of the of the Pacific. Captain O. W. Swainson of one," which actually A complete audio -modulator oscillator wireless operator Stier are shown op- extremely flexible design. With m- organization? and rophone, short wave set. or phonograph erating the device. pick-up attached to its input, it re- In the very beginning, this column and broadcasts its output a powerful We all have heard of the new law which tunable broadcast band signal to aerial ye editor were constantly advised of every terminal of any radio re e erior January first about all r, went into effect lr5c 'ion by the entire sosie bit of news and every move that was to so' spoon t foil speaker inpecicy. vessels of 2500 gross i or ocean-going passenger cubes, snort wave set reine Everything that was written in sta- be made. e tubes, e d befog in foreign - tons having to install radio -telegraph tions near heard before -on the broad this column was the truth, and, being con- tremendous volume! et receiver th installations, wave equipment in their motor lifeboats capable Uses, o Publia Address. oscillator sistently impartial and always carrying as experimental ham S.W. transmitter, beat fifty miles on conversion; feature s! et Price, On "for the of communicating at least all-wave etc. Many amazing Literature. forward a standard emblazoned ee - $7.95: nd now for FREE In $8.95 tube , Nit ultimate good of the Radio Operator," gave the international distress frequency. RIM RADIO MFG. CO. 695 Grand St., Brooklyn, N.Y.

~~www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 561~~

anticipation of it, a test was conducted by the RMCA with the equipment installed in motor lifeboat Number 4 of the S.S. Pennsylvania. This test indicated the pos- ARE sibilities of communicating at least 150 YOU LOOKING FOR miles from lifeboats at sea. This will add new duties to the radio ops aboard and A JOB ... OR A FUTURE? perhaps will put more radiomen to work installing and keeping the new apparatus in continual working condition. Some- PRACTICAL thing to look forward to for the coming RADIO ENGINEERING year, eh? Recently a letter was directed to us bawl- Insures a Future for Ambitious Men! ing us out for not being able to answer a question which had to deal with a matter We're interested in men who want Why don't YOU enjoy your success which only a Congressman FUTURES and not JOBS! Men while you CAN? Every day could know. who want to rise above the that you Therefore, we insist that this reply must ranks of neglect to prepare yourself for a bet- the average and uninteresting, routine ter job costs you money and lets "the come from a source which cannot be given work. There are always GOOD jobs other fellow" get ahead. CREI can out until ready for general publication. We for GOOD men. Years of experience help YOU as we have helped others. and contacts in the field have proven endeavor to answer all questions and prob- RIGHT now . WRITE now for that TECHNICAL TRAINING is full information about our Practical lems that the best of our knowledge and the "short cut" to success. Radio Engineering courses. our resources permit, but insist that we are not G -men or Houdinis. We will, at the first opportunity, convey to this subscriber SERVICEMEN! the proper answer when it is available. NEW 48 -PAGE ILLUSTRATED Last year this column wrote of the pos- Get the Facts Now About BOOKLET FREE! sibility of having weather maps transmitted in facsimile to ships at sea. This possi- Our New Course in bility has now turned into a reality and MAIL THIS COUPON TODAY ! this new service will be put into operation "SERVICE AND PUBLIC in a short time. The development of ter- CAPITOL RADIO ENGINEERING INST. ADDRESS Dept. RN -3, 14th & Park Rd., Washington, D. C. minal apparatus has been completed and ENGINEERING" Please send me complete details and illustrated lit- will be placed on four chosen erature regarding your new Course jn Service and vessels as Public Address Engineering and/or PRACTICAL they RADIO make their next call at the port of -for EXPERIENCED Servicemen ENGINEERING. N'Yoik. The ships are of American, Ger- only, who realize the importance of TECHNICAL TRAINING. Practical Name man, Norwegian and Spanish registry, ar- from the very first lesson, and written rangements having been previously made in your own language. Before you in- Address vest in any home -study course, write by Mr. Pannill when he was in Brussels for details and literature about this City last summer. This step toward extension new CREI Service Course. of the RMCA service to vessels of other nations is natural, since the American com- CAPITOL RADIO ENGINEERING INSTITUTE pany is the first in the world in this field 14th to have developed radio facsimile for ma- and Park Rd. Dept. RN -3 Washington, D. C. rine service. Short waves will be employed for transmission as in the present commercial transoceanic service of picture transmission. That part of the radio spectrum is best suited to long- distance work. The U. S. Weather Bureau will supply the great radio company daily with maps of the Atlantic and these will be sent to the ships on two different frequencies, one adapted to transmission up to about 1500 miles and the other suited to transmission over NEWS greater distances. The ops will thus be At last it's here! Another sensation that able to select the frequency of most effi- has warmed the hearts of even the skeptics. cient reception for their position. Just It's the new improved 193E version of the another duty for the overworked op. Amongst the batch of mail comes a re- mark from an embryonic radio op, "How BROWNING do some of the eastern schools obtain jobs 35 for their graduates with so many experi- With All Metal Tubes enced ops on the bench ?" Just one of VIBRATORS those questions we would like the answers Now you'll not only find all the features which made the original Browning 35 the to ! What matters right now is, will the outstanding new year kit development of 1935, but bring the advances and advan- also many refinements plus even better re- tages we expect to receive by reason of ception on the Short Waves. New prices; our past efforts in '35 or will it just be new circuit refinements; increased high fre- another year rolling by, bringing the same quency sensitivity! talks, the same arguments and the same "info "? It all sums up to this, "We get GEORGEOUS CONSOLE out of the jar that which we put into it "- CABINETS NOW AVAILABLE except when we put sweet apple cider in For and let it stand too long and then modernization jobs and for the set we get builder who seeks sheer beauty coupled with vinegar.... 73 ... ge ... GY. incomparable reception -the new Browning 35 Cabinets with new escutcheon plates will Tear out this ad and pin to be heartily welcomed. You'll be proud to have one in your living room. your letterhead For FREE Why not clip the coupon NOW -even if you Alnico own a Browning 35 -and get the news con- copy of the NEW UTAH cerning these latest Browning 35 develop- SCHENECTADY, N. Y. -A new alloy, General Catalog of ments. alnica, which can be made ino an excep- vitalized tionally powerful permanent magnet, has radio parts. Tobe Deutschmann Corp. been announced by the General Electric Canton. Massachusetts Co. Some magnets will lift 60 times their Send me full details concerning the new improved own weight. It is much harder to mag- UTAH RADIO Browning 35 with All Metal Tubes. netize than other materials but once magnetized, is better able to retain its PRODUCTS CO. Name magnetism. The Simonds Saw and Steel Address Co. of Lockport, N. Y., has been licensed Orleans St., Chicago to manufacture and sell C magnets of alnico. Lc'L Slate

~~www.americanradiohistory.com 562 RADIO NEWS FOR MARCH, 1936~~

~~Complete mechanism of the control, showing straight - path travel of contact shoe on resistance element.~~

NO WASTE MOTION in this ELECTRAD DIRECT CONTACT CARBON VOLUME CONTROL THE fewer the moving parts, the less chance for trouble ! This new Elec- trad design has but ONE moving unit. The special alloy floating contact shoe glides over the carbon resistance element in a straight path, insuring uniform pres- sure at all points ; smoother, quieter operation ; more positive, finer variation of current regulation. Self-cleaning-pol- ishes the carbon to glassy smoothness - A SHIPSHAPE DX CORNER IN AN ATTIC keeps it dust free. No skipping, leaping Bloomingdale, New Jersey, Official Listening Post Observer for or stuttering. Each Electrad Volume Earl Wickham of that State, is proud of his receiving rig. He is now getting his amateur license Control is tested for noise at the factory on the air. and is unqualifiedly guaranteed. Use an and will soon have a transmitter Electrad on your next service job. Write Dept. RN -3 for 1536 catalog. wave relay station for ZVNAC. The DX Corner (Bower.) XEFT, Vera Cruz, Mexico, 6120 kc. 175 Varick St.. New York. N.Y. (Short Waves) reported heard 11 a.m. -4 p.m., E.S.T., and 7:30 p.m. -12:30 a.m., also some- (Continued from page 548) times heard on 9600 kc. (Gallagher, ELEÇ=TRAD Meade, Evans, Hammersley.) W2XDV, 31600 kc., heard Satur- XEVI, Mexico City, Mexico, 5970 days and Sundays, 2 -5 p.m., and daily, kc., transmits Mondays, Wednesdays 7 (Portman.) Tuesdays 9 -10 RESISTOR SPECIALISTS -9 p.m., E.S.T. and Fridays 4 -5 p.m., Listening Post Observer and 11 p.m. Featuring: -Quiet Carbon Volume Controls. Official p.m., Thursdays 9 -10 p.m., Vitreous Resistors, Truvolt Resistors and Craft conducts a mighty fine short- midnight, Saturdays 2 -3 p.m., E.S.T. Power Rheostats. wave tip program, dedicated to RADIO (Butcher, Winand.) NEWS, every Friday evening at 12:45 XBJQ, Mexico City, Mexico, 1000 a.m. (really Saturday morning) on sta- more, but kc. kc., does not broadcast any tion KGGC, San Francisco, 1420 is heard occasionally testing with (This is fine business and we hope W2BSD. They have been reported other Listening Post Observers who heard daily, except Suwndays, at 10:30 conduct short -wave tip programs will a.m. and at 4:30 p.m. (Holt, Davis, do the same thing and let us know so that we can publish data in the DX LEARN TELEVISION with RADIO -NOW! Corner.- Editor.) OUR CALIFORNIA OBSERVER Fine opportunity for experts in this Ill., 6425 kc., re- amazing new industry. A NEW busi- W9XBS, Chicago, Meet R. J. McMahon, is an active ness in a NEW era offers NEW oppor- ported heard at 5:30 p.m., E.S.T. Observer on the Short-Waves, and tunities for big salaries! You learn is Radio and Television from beginning (Adams, Jr.) uses a Superskyrider and a Philco to end in our marvelously equipped certi- labs and studios. You actually operate WOEH, aboard the "Philippine All -Wave Receiver. Notice the thousands of dollars worth of expen- Clipper," is an N.B.C. transmitter in- ficate in the place of honor. sive equipment. You get expert m struction and skillful guidance by stalled aboard the flying ship and op- radio- television specialists. erates on 2670, 4797, 6425, 8655 and - Demand for Television Experts 12862.5 kc. The set was reported Television now perfected and ready for the market ON THE NEXT BIC heard 2100 miles from Alameda, Cali- BUYING WAVE. Business leaders predict Jensen, Moore, new system television will require thou- fornia. (Gallagher, sands of relay and broadcasting stations. Parker.) Ultra -short waves will permit eighty thousand television stations in America alone. KEE, 7715 kc., may be heard relay- GET IN NOW and "build with the world's next ing programs to 'Honolulu evenings. ltondollar industry. 6 MONTHS THOROUGH, (Hull.) PRACTICAL TRAINING Qualifies for radio-phone license W2XBJ, 9450 kc., may be heard at (1st Classl. Complete uprts -the minutetrainingon modern 'work. 8:30 p.m., E.S.T., testing with music. able" television equipment including the nevi eathoderay. Practical (Hull.) Trapenance in room nsmitter operation of Televis, 11970 kc. (some say it is ion Station W9iAl. Employment KKQ, ilWrite 11950 kc.) may be heard rebroadcast- FREE FOLDER nation. forrfee book Pit. tures On the Air" NOW! ing to Honolulu on Sundays 2 -2:30

S. Q. NOEL, Pres. First National Television, Inc. p.m., E.S.T., and also at 7:45 p.m., Dept. D -3 Power & Light Bldg., Kansas City, Mo. Är FREE Folder On the E.S.T. Ellsworth, Saubereich, Jones.) tellinglf about new opportunities in televisionl Itam1C17 older. Name KKP, Kahuku, on 16030 kc., has been heard testing at 1 p.m. and from 6 -6:30 p.m., E.S.T. (Wilson.) KKH, Kahuku, on 7520 kc., lias been NEW 1936 CATALOG heard rebroadcasting to the Columbia available shortly. Write today chain at 11:30 p.m. to 1 a.m., E.S.T. and get your name on our mailing (Hull, Kentzel, Bews, Jensen, Galla- list for this new catalog and the ILD latest authorized information on gher.) "r testing and analyzing the new Octal and Metal Tubes, the new KIO, 11680 kc., may be heard on Octal Analyzer Plugs. Sockets. Adopters. E.S.T. Grid 25.67 meters, 11:30 -12 midnight, all tall tubes sockettof your says teeter. List price $6.50. (Kentzel.) Observer Gallagher ALDEN PRODUCTS CO. the frequency is 11710 kc. Dept. RN -3 715 Centre St. Brockton, Mass. W1XAB is a new American short-

~~www.americanradiohistory.com J7~~

~~RADIO NEWS FOR MARCH, 1936 563~~

Akins, Dunn, Partner. Ortiz, Craft. Wolf, Butcher, Holt, Foshay, Sauber - lich, Dickes, Frost, Nosworthy, Lopez, Evans.) TG1X, Guatemala City, Guatemala, 9450 kc., heard irregularly. ( Holt.) TG2X, National Police, Guatemala. reported heard 4 -6 p.m. and 10 p.m.- 12 midnight, E.S.T. (Butcher, Holt, Dickes, Winand, Seright. Craft.) SOUTH AMERICA VP3MR, Georgetown, British Guiana. 7080 kc.. 42.4 meters, reported heard 7 -10:10 p.m. by some listeners. Other observers say daily 9 -10 a.m. and 7 -8 p.m., with additional programs on \Vednesdays, Thursdays and Satur- days from 5 -7 :30 p.m. (Hull, Skatzes, Reilly, Winand, N. C. Smith.) HJ3ABH, Bogota, Colombia, 5970 kc., 1200 watts, reported heard. (Holt.) HJSABC, Cali, Colombia, 6153 kc., reported heard 11 a.m. -12 noon, 7 -10 p.m., E.S.T., except Saturdays and EFFICIENT BUT SIMPLE Sundays. (Chambers.) This is the DX Corner of F. A. Pil- HJ5ABD, Cali, Colombia, 6487 kc., frim, Official RAO10 News Observer reported heard 9 -10 p.m., except Sun- for California whose home is at Oak- days. (Chambers.) land. Yes, he certainly pulls in some HJ4ABC, Medellin, Colombia, 6135 fine DX, especially the Asiatics. kc., reported heard 6:30 p.m. (Be- tances.) These call letters have also been reported as at Ibaque, Colombia, 5 Villar, Craft, Ortiz, Coover, Miller, on 6451 kc., and Whittaker, Messer.) also at Pereira, Co- lombia, on 6065 kc. or 6080 kc., trans- XEXA, Mexico City. Mexico, 6180 mitting at 10-11:15 p.m. Another OUT OF 52 kc., sta- reported heard 9 -10 p.m., E.S.T. tion, HJ4ABC, was reported on 6548 ( Portman.) kc., 7 -10 p.m. One listener says this Here are five NATIONAL Mid- CMA3, Havana, Cuba, 15505 kc., re- station was formerly HJ4ABJ at Pe- get Condensers -five of a line of ported heard Sundays 4 -4:30 p.m., reira. Evidently here is a decided E.S.T. (Hull.) mix -up and our readers would appre- fifty -two different models and CM6XJ, Havana, Cuba, ciate it if 15440 kc., our observers or anyone sizes of widely varying reported heard testing with phono- else could straighten out the mess. character- graph music. (Davis.) (Betances, Chambers, Wilkinson, istics, made by National to meet VRR3, Kingston, Jamaica, 3841 Johnson.) every special meters reported testing and giving HJN, Bogota, Colombia, approxi- and general re- news 5 -5:15 p.m., E.S.T. (Baier.) mately 5950 kc., heard 8 -11 p.m. quirement of short -wave radio. HI5N, Santo Domingo, D. R., 6130 (Craft, Gallagher, Chambers, Butcher, kc., 48.8 meters, reported heard 6 Wilkinson.) p.m.- SEC -heavy, double -spaced, poGsbcd, round edge, 11:30 p.m., E.S.T. (N. C. Smith, HJ4ABD, Medellin, Colombia, re- 270° SFL plates. Air gap .055. Isolantite insulation. Young.) ported heard at different times on the 15, 20 and 25 mmf. capacities. List prices (respectively) $2.50, $2.75, $2.75. HIL, Santo Domingo, D. R., 6505 following frequencies: 5750, 5760, kc., heard at noon and from 6:30 -7:30 5785, 5790, 6060, 6080, 6140 kc. They SEH -Air gap, .0175. 270° SF!, plates. Caps. 200, p.m. (Portman, Johnson, Betances, transmit irregularly from approxi- 250, 300 and 335 mmf. List prices (respectively), Wilkinson.) mately 7:30-11 or 11:30 p.m., E.S.T., $3.75, $4, $4, 54.25. HI(6Z ?), San Napier, D. R., re- daily. (Hynek, Chambers, Libby, STD- Double condenser, 180° SLR' plates, 50 mmf. Meade, Gallagher, Portman.) per section. Air gap, .026. Isolantite insulation. ported heard on about 6130 kc., late Constant -impedance HJ2ABD, Bucaramanga, rotor connection, insulated front - evenings. Does anyone know the Colombia, bearing. List price, $3.50. proper call and the correct frequency 5980 kc., reported heard 11:30 a.m. - and schedule? (Davis.) 12:15 p.m. and from 5:30 to 7 p.m. STS -lias 180° SLW plates, with air -gap of .0175. Also heard testing 1:30 -2 Single bearing, with constant impedance rotor con- HIZ, Santo Domingo, D. R., 6340 a.m., E.S.T. nection. Made in 1.5, 25 and 50 mmf. List prices, kc., 47.5 meters. reported heard 7:30- (Chambers, Libby.) $1.40, 81.50 and 51.60. 9:30 p.m., E.S.T. (N. HJ4ABA, Medellin, Colombia, has C. Smith, Ells- changed frequency SE-Has 270° SFL plates with air gap of .026. Made worth, Dickes.) from 11710 kc. to in 50, 75, 100, and 150 mmf. List prices, $3.00, $3.25, 11820 kc. They are reported heard 53.50 and 53.75. CENTRAL AMERICA 11:30 a.m. -1 p.m. and from 6:30 -10:30 p.m., All list prices subject to 40% discount when pur- YNVA, Managua, Nicaragua, re- E.S.T. Atkinson, Libby, Holt, chased through an authorized distributor. Betances, Skatzes.) Send coupon below for new Catalogue No. 250, de- ported heard on approximately 8600 scribing the full kc., 8 p.m. (Betances.) HJU, Buenaventura, Colombia. 33.1 line of NATIONAL Radio Products. meters, HP5F, Colon. Panama, 6070 kc., re- reported heard Wednesdays and Saturdays, 11 ported heard 11:45 a.m. -1 p.m. and -11:45 p.m., E.S.T. 7:45 -10 p.m. Reported heard Sundays YV5AM, Maracay, Venezuela, 7105 kc., reported heard 10 -1 NATIONAL 4 -6 p.m. (Partner.) a.m. regularly and from 6 -10 p.m., E.S.T. On some TI5HH, San Jose, Costa Rica, 5500 nights has been kc., 54.5 meters, heard acknowledging MIDGET CONDENSERS reported heard 2:30 -4 letters and talking to amateurs. (Pick- p.m. and from 7 -11:30 pm., E.S.T. ering, Wickham, Portman, Butcher.) (Betances, Villar, Holt.) YV8RB, Barquisimeto, San Jose, Venezuela, TIPG, Costa Rica, 6410 5880 kc., reported heard daily 5 -7 kc., 46.8 meters on the p.m., NATIONAL COMPANY, INC. air 6:30 -11:30 E.S.T., Thursdays 5 -8 p.m., E.S.T. p.m. (Dooley, Craft, Holt, Libby, (Wilkinson says the last MALDEN, MASSACHUSETTS Young, Miller, letter of this Wolf, Dickes, Foshay, call is B instead of a V, as listed in Gentlemen: Skatzes, Akins, Please Whittaker Hynek.) previous months.) (Ortiz, Chambers, send me your new catalogue No. 250. I en- HIW, Honduras, 27.15 meters, re- Butcher, Libby, Foshay.) close Sc to cover mailing costs. ported heard testing at 11 a.m. (Holt.) YV12RM, Maracay, Venezuela, 6300 HRN, Tegucigalpa, Honduras, 5875 kc., 47.6 meters, heard testing and Address kc., 500 watts, reported heard daily 12 broadcasting between the hours of 7 noon -1 p.m., 6 -7:30 p.m. and 8 -9:30 and 11 p.m., E.S.T. (Kentzel, Foshay, p.m. They are also reported heard on Skatzes. Craft, Akins, Pasquale, Be- Sundáys 3 -5 p.m. and 10:30 -11 p.m. tances, Butcher, Lawton.) (Norman, Johnson, Bower, Chambers, (Turn to next page)

~~www.americanradiohistory.com 564 RADIO NEWS FOR MARCH, 19$~~

YV4RV, Venezuela, reported heard Shields, 25 Bluestone, Moston, Manchester 6675 kc., irregularly 8 -9 p.m. (Jones.) 10, England. HC2RV, Guayaquil, Ecuador, reported heard on 45 meters. (N. C. The Globe Circlers' DX Club Smith.) Officials of the club welcome Mrs. Ibbie HCJB, Quito, Ecuador, has changed Smith of Carroll, Ohio, to their ranks. its frequency to 8900 kc. (Betances, Akins, Messer.) No More Verifications OCEANIA An announcement by W8XK of importance to short -wave club members the Tahiti, 7 -1 mega- "Radio Oceanie," world over is an announcement recently cycles, is reported as a new station They and Fridays, received from W8XK and W1XK. transmitting Tuesdays have received so many letters daily saying 11 p.m.- midnight. (Wilson, Pasquale.) that their transmissions are considered as local by listeners all over the world that Readers Who Are Awarded they are discontinuing short -wave recep- "Honorable Mention" for Their tion reports. Work in Connection with This Short -Wave Institute of America Month's Short -Wave Report An announcement was recently received Announcing! the Juan Manuel Salazar, L. C. Styles, Robert Nelson, regarding the formation of the Short Wave Loring Young, A. T. Hull Jr., J. W. organized at Wash- ALL -STAR TRANSMITTER Charles Holt, Paul V. Trice, C. K. McConnan, Institute of America, R. Lawton, Isaac T. Davis, Arthur Immicke, ington, D. C., with offices in the National (Build If Yourself!) Ferry Friedl, Milton Prashaw, Jack Perry, Press Building, and with O. F. Schuett as Richard O. Lamb Thomas P. Jordan, Jose L. Any amateur, with screw driver, pliers and President. One of the purposes of the NOW!soldering iron, and only a kitchen table to work Lopez, Dr. Evelio Villar, Lewis F. Miller, Frank on, can build the professional -looking, efficient ALL - Nosworthy, Paul J. Mraz, Earle R. Wickham, Short Wave Institute will be to provide STAR TRANSMITTER- n-hich combines the engi- Werner Howald, George James Ellsworth, Orval a clearing house for schedules of stations neering skill of seven leading sponsor -manufacturers. Francis T. Reilly, Dickes, Walter W. Winand, and the distribution of these schedules to 40 to 500 Watts Waste! J. T. Atkinson, Howard T. Newpert, Fred Cox, -No Manuel E. Betances, Caleb Wilkinson, J. E. set owners. Start with 40 -watt, CW or phone. Expand to 500 - Moore Jr., B. L. Cummins, Roger Jensen, Louis watt CW or 400 -watt plate modulated phone. All R. Dunn, parts and values tested. Nothing need be discarded. Horwath Jr., H. H. Parker, Thomas Monongahela Radio Club Foundation units drilled and machined, ready for J. E. Wilson, George J. Pasquale, George C. assembly. Akins, Robert B. Hammersley, Arthur Evans, The Monongahela Radio Club elected of- Jerry M. Hynek, Walter F. Johnson, Walter L. Specified Parts Stocked by Jobber Chambers, H. Westman, C. H. Skatzes, John ficers for 1936: President -Willis Hodgson Specified parts approved by the designers are stocked G. McConomy, Harry E. Kentzel, Edward De- -(Station W8IQX) ; First Vice Pres. -W. by your jobber, and made by these sponsor-manufac- Laet, Merton T. Meade, J. Wendell Partner, N. Reimensnyder, of the Bell Telephone turers-THORDARSON ELEC. MFG. CO. -HAM- Jack Bews, L. M. Jensen, Manuel Ortiz G., MARI.CND- MFG. CO.- CORNELL- DUBILIER Second Vice Pres. -Frank Pedrosky- CORI'.- TRIPLETT ELEC. INST. CO.- OHMITE G. C. Gallagher, R. Messer, Albert Pickering Co., MEG. CO. -E. F. JOHNSON CO. -CROWE NAME Jr., V. D. Seright, W. Bernard Kinzel, Jose (Station WSNUS) ; Third Vice Pres.- PLATE MFG. CO. Rodriguez R., Claude H. Dalyrymple, Paul Clyde Crookham- Coshocton Iron Co.; Fayes, Fred M. Craft, L. M. Jensen, Eric See Your Jobber or Write Butcher, Howard Adams Jr., Reeve Owen, Sec. -L. C. Healy-Monongahela Publish- * BVILDV ROWN * George W. Osbahr, A. Fabius, Oliver Amlie, ing Co.; Treas. -Lee Hagerty -(Station ALL -STAR Gideon Brainard, Morgan Foshay, Frank J. W8MTT). HEADQUARTERS Flora, J. Leslie Berts, Preston C. Richardson, Wheeler T. Thompson, M. Keith Libby, Bruce Club Bulletins will be published each ALLSTAR 222 W. Adams St. Chicago. TRANSMITTER Holmgren, Arthur B. Coover, Clarence Norman, month and mailed to every member in John F. Fritsch, W. C. Reichardt, Rene Arickx, good standing. Code Practice will be held George L. Loke, Mike Kruger, Howard Sauber- lich, Wm. J. Roberts, Ellsworth Dumas, E. L. each week at a place designated. The Frost, Lyman F. Barry, A. J. Hull Jr., E. W. station and time of each practice will be Turner, Charles C. Dooley, N. C. Smith, A. H. printed in the monthly bulletin. Honorary Dalai, R. H. Graham, Pierre A. Portmann, Terry A. Adams, Gabriel M. Costes, C. McCormick, membership is accepted at 25 cents a year PER/TE HI GH LEYELYELHCITS' Kenneth R. Boord, Edward Pohlig, Carleton L. along with QSL card and self- addressed L. Gallagher-, Charles E. Pellatt, Operates WITHOUT PRE -AMP ELIMINATES Whittaker, F. envelope with postage will bring the HUM TROUBLE Harry Wolf, Robert A. Curtis, Paul W. Craven, to place in the H IGH IMPEDANCE-2000 OHMS Vincent S'. Cigoj, J. L. Torres, A. T. Hull, monthly bulletins any THIS MICROPHONE IS HIGH James Floyd, J. V. Caneghem, Forrest W. Dodge, world. ENOUGH IN IMPEDANCE TO W. W. Gaunt Jr., R. N. Putnam, Francisco The club meets every Friday at 8 o'clock. OPERATE DIRECTLY INTO Fossa Andersen, Omega Verzecchi, Frank E. GRID ... BUT NOT HIGH Baier, Robert F. Gaiser, Harold W. Bower, J. S. Plans are in progress to hold a RADIO ENOUGH (ONLY 2000 OHMS) L. Hintzbergen, David H. Henderson, BANQUET some time in March. The SERIOUS Phillips, TO INTRODUCE Charles C. Norton, J. P. Baas, L. C. Healey, club has 15 Amateur Radio Station owners LOSSES IN LINE UP TO 200'. Steven P. Veres, Isidro Palacio, Earle R. Wick- ; 12 5 Engineers; 18 Replaces condenser and crystal ham, Fred A. Pilgrim, Edgar J. Vassallo, W. E. enrolled Servicemen; t.. n::ces. No changes necessary. Frost. S.W.L.; 2 Police operators; 3 Television El^"rotes input transformer MODEL RE -H. for engineers; 2 Broadcasts announcers. and its losses. Eliminates hum speech and music. trouble and feedback. LIST $42.00 with coupling. MODEL RS -H. for International DX'ers Alliance speech, but can also S. W. Club News POSITIVE-Rnn- be used for music. LIST The officers of the International DX'ers $32.0 with coupling. is 'smooTH-RCrloll Write for Bulletin H. Army Amateur Radio System Alliance announce that this the start of sTAnDs the fourth year of the existence of the The Second Corps Area of the Army Globe Circlers' Official Publication organ Amateur Radio System publishes a monthly of that association. Members are re- Positive, non -sliding, ball-bear- in which Army Amateur news is ing clutch! Will never wear out bulletin quested not to forget that the member- never require adjustment. given, with announcements of contests, ship drive is still on. WILL NOT "CREEP ". Tightens hamfests, report cards and items of inter- Mike Radio News Listening Post Observers with only 1/8 turn of clutch. to the organization in general. Reports can be rotated without loosening est welcome to the I.D.A. fold, and as readers clutch. SMOOTH, PNEUMATIC - of the Jersey and Hudson District Nets of Radio News thirty -two new members LIKE ACTION up and down. A as well as the Adirondack and Western for the past month. model for every purpose. WRITE New York sections are printed. Requests FOR ILLUSTRATED BULLETIN S. for information about the Net should be The New Zealand DX Radio made to Col. Alvin C. Voris, Governor's AMPER/TE any, 561. BROADWAY NEW YORK Association Cm Island, New York. AMPERITE H,-,rt4tu,, - The President of this association an- Society of Wireless Pioneers nounces twenty -four new members bring- MICROPHONE to 903 end - society of wireless Pioneers members ing the total by the of the The members send photographs of their shacks year. Prospective should send will please membership applications, care of HQ for possible publication in RADIO in their to Radio News and they will be forwarded. NEWS. Data should be included. The Vice -President asks why we can't get a bit North Manchester Radio Society of coöperation between radio manufacturers and the electrical concerns making The North Manchester Radio Society ENGINEERING, nerve -wracking interference -producing de- was inaugurated at a meeting held at the broadcasting, aviation and police radio, servicing, marine Manchester, radio telegraphy and telephony, Morse telegraphy and vices that create such havoc with short- British Legion, Whitefield, railway accounting taught thoroughly. Engineering reception. Automobiles are among England on Friday, 25th October, 1935. course of nine months' duration equivalent to three wave years of college radio work. School established 1874. the worst offenders. British and European The officers are Mr. R. Lawton, Secretary- All expenses tow. Catalog free. and Short -Wave Director, Mr. Dodge's Institute, Oak St., Valparaiso, Indiana members, please send news items to H. B. Treasurer

~~www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 565~~

A. Wimtanlev, Technical Adviser, and Mr. rigid but also provides a firm anchorage for the L. Hoyle, Chairman. Meetings are held lead -in. The lead -in is a parallel pair with the wires every Friday at 8 p.m., the room oczaitn, being spaced two inches apart as shown in Figure 1. RADIç open for the use of members from 7 p.m. In such a combination, the two wires are fanned For those interested Morse instructions are out beginning. at a point 30 inches from the REAL RADIO ENGINEERS! antenna, and spreading to a distance of 28 given from 7:30 to 8 p.m. Lectures and inches where they connect to the antenna rod. demonstrations are given from time to time This type of lead -in should be continued at a by representatives of the various manu- right angle to the antenna rod for a 'A -wave (4 feet) and from that point on may be run to facturers, also visits are made to places the receiver at any desired angle. of interest, such as Radio factories, Power Another excellent receiving antenna system Kendall Gieerh employs an 8 -foot copper with the Cnmi Eneineer. Stations, B.B.C. Studios, Control room, rod single Cloueh-a,encle Co. wire lead -in taken off the top end as shown E. E. Granule etc. The society endeavors to cater to in figure 2. EVIEá iinsrormer Co. beginners as well as the keen "DX" and There are numerous other effective types of Karl E. 'Wesel Train Now at Home 5 -meter receiving short -wave "fans ". All meetings are open antennas but the two mentioned iminsááióe`corp. have the advantage of high efficiency and sim- K. C. Time for Good Pay. Spare - to anyone interested in radio. Further plicity. tia«r. Incidently, the 8 -foot length is selected c ó.w' á±;áió particulars can be obtained from the Sec- not as a matter of convenience, but because this F. D. Whitten Time and Full Hamner. Time length resonates (Y,-wave) 5 Service Phitee retary, Mr. R. Lawton, 10, Dalton Avenue, at meters and Radio @ Tclevjbion Corp. therefore, provides extremely effective pick -up Dr. C. M. Blecxhern Jobs that Pay up to Thatch Leach Lane, Whitefield, near Man- for 5 meter signals. Any Rndio En¢inecr, type of antenna, in- l'. R, niallary & Co.. chester, England. cluding a broadcast receiver antenna, will provide a certain amount of pick -up at 5 meters but such antennas are very definitely less effective International 6000 -12,500 Mile than the types shown. The foregoing is not intended to be a real Club comprehensive discussion of 5 -meter equipment but rather to bring out a number of fundamental $ 75 a week ideas gleaned front observation and experimen- We are having new membership cards If you're tation to date and it is hoped that the informa- future- dissatisfied with small pay -and an uncertain made up; these cards will be for both the tion given will prove helpful to many who are here's an opportunity that's too good to miss. Get my big FREE book, "RADIO'S FUTURE AND YOURS." S.W. and B.C. listeners, the cards will be becoming interested in 5 -meter work for the This book first time. tells how you can learn at home under the well designed, and anyone owning one of supervision of factors- engineers, to make more motley al- Next month the second article of this series most at once in Radio-how to make Radio your life's these can be PROUD of same. will include descriptions of several 5 -meter re- work. or use it to pielt us 55 to $20 a week extra in spare time. your New 9 by 12 membership certificates ceivers now on the market, including those of both the superheterodyne and super- regenerative may also be had, only members holding types. MORE OPPORTUNITIES THAN EVER BEFORE a 20 point verification over 6000 miles on Radio is still forging ahead. 1935 was its biggest year. S.W. or 3,500 miles on B.C. and 40 point Over 5 million new sets sold. Over 30 million dollars paid for service alone in 1935. Where only a few hundred men verification will receive one of these certif- were employed a short time ago, thousands are employed icates; 20 point makes any one a PRO- today. And where a hundred jobs paid up to $75 a week Antenna Mast -there are thousands of such jobs today -many paying FESSIONAL DX ACE, 40 veries DOCTOR even mare. New full time jobs and spare time jobs are being created all the time. Get my book and see OF DEGREES CERTIFICATE. Mr. W. (Continued from page 527) easy you can get started. how of North Island, N. Z. becomes Warren "SHOP TRAINING" District manager for that zone, Mr. F. After the collapsed mast has been FOR THE HOME R -T-I Training Ridler of England becomes District man- mounted on the roof or parapet, guy is different. It comes to you right from the heart of the Radio Industry -right out of the fac- ager of that zone, the club is gaining mem- wires are attached to the top of the base tories where Radio sets and other vacuum -tulle devices are made. It was bers fast, let's sec what kind of a DX'er section and securely fastened planned and prepared and is supervised by to points of big radio engineers IN these factories -by men appointed support on the roof. for the purpose. R -T-I will train you you are. Guy wires of suit- try wants as the Radio Indus- able length are then attached to the per- you trained. forated collar at the top of the top sec- TELEVISION, PHOTO ELECTRIC CELLS, PUBLIC tion and left dangling, to be attached to ADDRESS SYSTEMS INCLUDED anchorages on Radio servire work is plentiful but it's only the the roof after the mast is Point in R -T -I Training. starting Get Going! raised. A From there you'll go through pulley is also wired to this top the whole field of Radio and collar and a rope or other halyard run Electronics. You will learn (Continued fron page 529) about every new develop- through it. The mast is then elevated by ment, including Television first pulling out the top section and by MAKES $600 IN ONE so you'll be ready when 40 to 100 kc. wide. Such selectivity as is de- MONTH Television breaks. You'll sired is then obtained in the r.f. circuits ahead locking it by means of an ingenious screw also learn the big money Herbert h. Thomson, Gor- subjects such as of the intermediate amplifiers. lock which does not require the use of any man, Texas, started making Aviation It is a common practice to use the autodyne and Auto Radio; Public tool. The i Address system of frequency conversion. To accomplish second section is then pulled ehed: e saye,e' Beeouee Systems; how to out, raising my handle Photo Cells; Sound this the first detector is used in an oscillating the top section with it and made $4 0 i September Picture Recording, Etc. on over $650 in October condition and instead of being tuned to peak locking it. Finally the third section is 1935. vIt pays to be R-T -I signals it is tuned enough off the signal fre- raised and locked, Trained." 4 WORKING OUTFITS quency to beat the signal to the intermediate bringing the mast to its FURNISHED To make this practical, the inter- full height. The loose ends of the top frequency. BIG MONEY IN Start almost at once doing mediate frequency selected is of a very low guys are then firmly anchored and the AUTO AND POLICE part time radio work. I neighborhood 20 or 30 order, usually in the of job is finished, the whole RADIO WORK furnish 4 outfits of appara- kc. so that the detuning of the first detector will thing having tus that you build into test not materially reduce signal strength. Many taken little more time than it takes to W. H. Carr, 402 N. 16th equipment with which you 01., Kansas city. Hans., can do actual jobs and experimental superheterodynes are provided with harde earn describe the process. An outstanding fea- R -T -I tudent, has extra money. Sly Training a preselector stage with the object of improv- of 35 rodeo equipped Police ture of the mast is that a ladder is not d Fire Department ea pays its own way, and you ing the signal -to -noise ratio and also of prevent- He gets $230.00 n month get your money back if not ing radiation from the oscillating detector. There required, the entire job being accomplished d free auto, gas, oil, etc. satisfied. Age or lack He says, "If I had not tak- of are, in some instances, a resulting improvement by one man with his feet firmly planted en your course I would not experience is no handicap. in sensitivity. one be able to hold this job ". in signal selectivity and The on the roof. FREE weakness of the superheterodyne is that it lacks BOOK the noise -reducing characteristic of the super - The manufacturers of the mast also have Find out why R -T-I Trained regenerative receiver. a complete line of mast and antenna men get "Quick Results" Unquestionably the ideal receiver installation and "Big Results." Send accessories available. These include guy - for "Radio's Future for a 5 -meter amateur station would consist of and wire anchors, with thumb -screws to ad- Yours" today. It tells two receivers, one of each type. With a low about Radio's amazing op- prevailing -noise condition the superheterodyne just the tension of the wire, insulator portunities. It de- receiver could be employed for weak signals; or brackets, truss braces scribes my approved at times, when the 5-meter band is crowded .with (for use where the training -what R.T.I. signals, advantage could he taken of the superior mast is erected at the edge of a roof and students are do- selectivity of the superheterodyne. When the a backstay is therefore impossible), antenna ing and making. noise grew lead or where high selec- It gives the conditions tension insulators (for keeping the an- names of 50 firms tivity is not needed the super -regenerative re- who endorse and ceiver can be switched in. It is more than likely tenna taut). Mast sections are available, recommend R -T-I. that some manufacturer will produce a receiver singly, or in groups up to four sections, It's FREE. in which are continued these two circuits with a the latter providing a height of 13 feet. Ray D. Smith switch to permit either one to be selected as PresidentRadio required. In fact recent experimental develop- An extension section is also available to and Television ments at headquarters of the American Radio provide a maximum height of 16 feet. Institute Dept. 43, 2150 League have produced a superheterodyne re- In addition to the ease of erection, these Lawrence Ave., Chicago ceiver employing a super- regenerative second detector. This experimental circuit is said to masts are pleasing in appearance and sur- MAIL COUPON FOR FREE BOOK combine the sensitivity and selectivity of the prisingly rigid. A 4- section mast installed RAY D. SMITH, President superheterodyne with the noise eliminating qual- in the City Listening Post is used to sup- Radio and Television Institute (R-T -1) ities of the super -regenerative circuit. 2150 Lawrence Ave., Dept. 43 In 5 -meter reception, the antenna plays an port two doublet antennas, both with Chicago, Ill. extremely important part and for best results the long, heavy, twisted -pair lead -ins and in Without obligating me, send FREE Book about spare - antenna should be one which resonates at 5 spite of this double strain there is not time and full -time Radio opportunities and how I can meters and should be a vertical rather than a train for them at home. horizontal wire. the slightest bend or distortion of the mast. The most common practice is to employ an Finally the cost is so low as to pay for Name 8 -foot length of 4-inch copper tubing mounted itself in the labor saved over required Address in a vertical position and supported means that by in erecting an ordinary iron pipe or wood of stand -off insulators on a wood mast. This L,ty State type of mounting not only holds the copper tubing mast. J

www.americanradiohistory.com 566 RADIO NEWS FOR MARCH, 1936 The DX Corner (Broadcast -band) (Continued front page 542) 1935 season. The Japanese stations and XGOA are the only Trans -pacific stations that can be depended upon for daily reception. Quite a few of the Australians have been heard, but rarely. IYA is the best of the New Zealand stations Get Into a Line heard, but the signal strength is about half of that noted last season. Signals from the eastern Where There's part of the United States and Cuba are much better than last year, many of the eastern sta- Day tions are well received at 4 :00 p.m. PST. The Action -Every - Analyzer & DX'es from the Cubans are being heard from And a Payday Every Resistance 90 to 100% readable, but middle Westerners on Tester DX are hard to read 50 %. Week -You Be the Boss! - I have received the following information cov- Latest ering Australian stations from the Postmaster - Right now while hundreds are Design - General's Department at Melbourne under date looking for work where there isn't Yours With- of November 4th: field can use any, the radio service out Extra New Stations trained men. With the proper Cost training and the necessary equip- 3GT, Gippsland Regional (Longford near Sale, ment, you can enter this field Vic), 830 kc., 7 kw. and make a comfortable living. We incmde with our course this modern set analyzer and trouble shooter with- 2GZ. Country Broadcasting Services Ltd., P. O. out any extra charge. This piece of equipment has Box 3650 S, Sydney, 990 kc., 2 kw. proved to be a valuable help to our members. After a Cumming brief period of training, you can take the set analyzer 3MB, Mallee Broadcasting Pty Ltd., out on service calls and really compete with "old timers." Ave., Birchip, Vic., 1470 kc., 100 watts. We show you flow to wire rooms for radio -install auto Wireless Ltd., 47 York St., sets -build and install short -wave receivers -analyze and 4PM, Amalgamated repair all types of radio sets -and many other profitable Sydney (station location-Port Moresby, ERIC BUTCHER WINS NEW jobs can be yours. Teaching you this interesting work is Papua), 1360 kc., 100 watts. HONORS our business and we have provided ourselves with every Ltd., Wilson St., Burnie, facility to help you learn quickly yet thoroughly. If you 7BU, Findlays Pty Eric, shown here with his Scott All - possess average intelligence and the desire to make real Tasmania, 1390 kc., 50 watts. progress on your own merits, you will be interested. Wave, has been appointed vice- presi- Changes dent of the 6000-12500 Mile DX Short - ACT NOW -- -MAIL COUPON 3AR, changed frequency from 630 kc. to 580 kc. Wave Club, in charge of broadcast - Start this very minute! Send for full details of our plan 7NT, changed from 750 kc. to 710 kc. band activities. and free booklet that explains how easily You can now cash 3MA, 900 kc., increased power from 50 watts to in on radio quickly. Don't put it off Wrlte today! 100 watts. Send nowt 3WR, 1260 kc., reduced power from 1000 to 7 feel sure that the other Observers join us in r 500 watts. him a speedy recovery. RADIO TRAINING ASSN. of AMERICA (Pennsylvania): XEAQ wishing Ravenswood Ave., Chicago, M. Observer Gordon Obscurer Pellatt (England) : Paris P.T.T. Dept. RN -63, 4513 was a new station testing on 1090 kc. and will Send me details of your Enrollment Plan in and Lyons P.T.T. have increased power to 80 kw. Gentlemen: real money probably be in regular operation sometime Fecamp and Poste Parisien are and information on how to learn to make should be addressed to the Reports on in radio quick. January. Reports wanted. Send them to the International Broad- station in care of Rosario Beach Country Club, casting Company, II Hallam Street, London Rosario, Mexico. WI, England. Luxembourg reports should go Name Francis L. McCray (Pennsylvania) : Am still to the same address. The I.B.C. programs are using the All Star Senior with a 138 foot an- carried by Luxembourg, Athlone, Poste Parisien Address tenna but have added the RADIO News Tenatuner and Fecamp, and are not carried by Frankfurt and find that it brings in stations that I have as implied by Observer Tomlinson. State. never heard before. Observer Coales (England) : Have been City Routzahn (Pennsylvania) is work- out the RADIO News Tenatuner on a re- Observer at testing ing 10 hours a day; playing in an orchestra ceiver employing 1 r.f., detector, and audio tube night and trying to study a radio course in be- and, with an indifferent antenna, the tenatuner tween times, which doesn't leave him very much produced a big gain and the wave trap circuit time for DX. In spite of this he has found time functioned very well. The next test was on a to add a few stations to his log, bringing the receiver having an untuned r.f stage. In this total to 898. He passes along a report from case the tenatuner brought about a large gain Observer Mathie in which it is stated that the in both selectivity and signal strength. The final new French station in New Caledonia, Oceania test was made on his big superhet and it was an on 600 kc. closes down Wednesdays and Satur- unqualified success not only in increasing signal days at 4 p.m., EST with the French National strength but also, when used as a wave trap, it Anthem. cut the most powerful transmitters down to a Observer Grosvenor (Kansas) reports that whisper. The tenatuner tunes nice and sharply. his log now stands at 833 stations. Of these 347 He winds up his report with the statement "I are verified. He writes for verifications only can thoroughly recommend this Tenatuner to all on low power or real DX stations and has been DX'ers and RADIO NEWS is to be congratulated accumulating these verifications for only two on an excellent job." years. He sends in a beautiful chronological re- Observer Jurd (Australia) writes that a port of his recent DX'ing and it is regretted "Radio Listeners League" has been formed in that space prevents its presentation here. Townsville and already has . a membership of `0.00r, Observer Golson (Louisiana) Engineer and 400. He has been elected Vice President and for a vote of would like to correspond with similar clubs in "What What DX Announcer of WJBO qualifies pep! for his cooperation in putting on the spe- the United States in order to exchange views on power! Take a tip. thanks matters in general. Letters should be ad- IIams and Experimenters - cial DX programs from WJBO which have been radio You can't beat ALLIED dedicated to RADIO NEWS Listening Post Ob- dressed to Aubrey R. Jurd, Livingstone St., matched kits when you're building your servers. West End, Townsville N. Q.; Australia. own. I never knew it would be so easy to Dakota): Observer Tucker (Alaska) in a letter (via set. Every part fits right; all I Observer Olive Johnson (South build this to Mrs. Johnson who has recently dog sled) dated December 9th reports European did was follow the diagram and presto - Our sympathy stations just starting to come in. On that date here it isl Say, if ALLIED can make set - been suffering from a bad cold -not to the com- building this easy -I'm going to build DX activities, however. he heard 21 stations in England and Germany. plete exclusion of U. west coast stations are heard beginning at more sets. ALLIED says they can supply Observer Covert (California) is doing a fine S. FREE parts lists for any circuit; I'm KGGC weekly 2 p.m. Mexicans are heard during the evening. got job in preparing the script for the going to take 'em up on It. They've to RADIO News. He He reports that from sunrise to sunset there is what I need and they save me money. I'm tips broadcasts dedicated absolutely no static; during the evening there clamed glad I've got an ALLIED Catalog and Andy Potter, manager of that station, are which should be is sometimes a little, increasing towards mid- handy -it certainly pays!" planning some new features night. In the early morning the static is so Send for FREE catalog. (Dept. M.) mighty interesting to DX listeners. Observer 1250 kc., is on Sun- intense that only the very strongest signals can Covert reports that KFOX, be heard. day mornings until after 4 a.m., EST; KMTR ALLIED RADIO on until 4 a.m. Sunday mornings. KSFO re- 833 W. JACKSON BLVD. broadcasts evening programs from KNX; also KJBS and KQW rebroadcast each other from II CHICAGO, ILLINOIS time to time. Requests for verifications on these stations should therefore include quotations Impedance Match from announcements, as a report on program serve as proof of reception. (Continued from page 538) QUALITY recommends material doesn't Observer- Ellis (California) is again editing "The Circlette ", official organ of the IDA, Sec- Substituting in the formula, we have ond District. 40000 2 Observer Butcher (Wyoming) started col- r lecting verifications in 1934 and now has them DB loss = lo log [1 -- J from stations in 34 countries with a total of 125 37680 foreign verifications. He has recently been appointed Vice -President of the International = 10 log [1 -I -1.18] cast Club = 10 log 2.18 = 10 X .32387 e s and r best WET ...DRY Band sectio)X Congratulations = 3.24 decibels ap- PAPER wishes. Law (Alberta) was laid up in the . proximately MICA ... TRIMMER Observer returned home. is useful in design work for Please Write for Details hospital and has just recently Formula (1) He writes that during his absence Mrs. Law predicting the low- frequency loss of a 599-601 Broadway to know he has MFG. CORP. carried on the DX work. Glad transformer. For example, when wLp = Z. SOLAR New York City recovered sufficiently to return home and we

~~www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 567~~

= Z,,,- the- response curve will -bp down 2. LL almost may also be an important factor exactly 1 decibel. Similarly," when in the same frequency region. wL Z /2 - Zb /2, the response will be 3. The ultimate characteristic will down 3 decibels, prob- etc. ably be determined by resonance between Over the middle frequency range (i.e., LL and Ca. from about 200 to 6000 cycles), none of In cases where Zb approaches open cir- the elements shown in Figure 1 are apt to cuit conditions, the transformer is said to show much frequency discrimination. This be "unloaded. Our equivalent circuit ON statement is -41 must be qualified, of course, by then the same as Figure 1 without Z,,. the type of unit under Note that consideration. In the loss for this condition is 3 AUTO a line -to -line transformer, for example, Ca decibels when any one of the following RADIO WORK! is apt to be relatively unimportant be- relations exist for the unity ratio trans- cause the value of Zb is of the order of a former. few hundred ohms. Hence, the high -fre- Z:, = wLL quency response of this type of unit will 1 probably be controlled almost exclusively Z:, _ by LL. In a line -to -grid transformer, on CCa the other hand, both LL and Ca, as well as resonance between the two, will set the In our next installment we hope to limit dis- for high -frequency response. This is cuss some additional problems of the ap- due primarily to the fact that Zb for the plication of audio -frequency transformers grid of a tube is very high. From the to impedance matching and relating prob- standpoint of circuit analysis, it may often lems. be considered infinite. Figure 3 is an equivalent circuit for Erratum leakage reactance, considered by itself. It in Part IV enters as a series impedance to the transfer Equation (3) as printed: of energy from Z to Zb. Its loss -producing I., Zs IsZ I Z=O effects will be important only when it be- Equation (3) as it should read: comes of the same order of magnitude as LZn+IsZL--IpZ,,, =O Z and Zb. Then it acts just as a series inductance between them. Formula (2) gives this loss in decibels. 24 -Tube Super Good Instruments Decibels loss due only (Continued from page 539) to reactance of LL } - make it more profitable resistors are mounted on the same shaft and this ¡1 (Za -i- Zb)2 - (WLL)- control is known as the micro -tenuator. When 20 log (2) no resistance is in the tuned circuit, when the that is, Z:, Zb lever of the micro- tenuator has been More and more of the auto radio servicing T / turned all the way to the right as far as it will Now let us calculate the loss due to LL go, the i.f. amplifier has the greatest selectivity is being done by independent servicemen and the greatest sensitivity. Turning when we have the following constants: toward this lever are the left will increase the resistance in -who properly equipped to do it effi- Z:, = 200 ohms the tuned circuit and thereby make the amplifier ciently. Z,, = 200 ohms broader and at the same time less Good instruments are a requisite passing sensitive, for LL = .01 henry a wider audio range for high -fidelity to get this work, reproduction providing better quality. and handle it profitably. 10,000 cycles high- fidelity For best f = reception, this lever should be With WESTON servicing Substituting in the formula, turned all the way to the left. equipment you we have The 6H6 tube serves as second detector only can gain the confidence of auto dealers x/16 + 39.44 X 100 and has no connection with the a.v.c circuit. The signal for the automatic volume and owners and build up a steady DB loss = 20 log taken control is business. from the plate circuit of the first i.f. 400 amplifier tube and fed to the grid For WESTON instruments mark their / 6K7 a.v.c. of a special 7.446 amplifier tube. After being amplified, owner as a careful, the signal is coupled to another 6H6 tube competent craftsman; = 20 log serves as a which rectifier for the automatic volume and enable him to do 4 control. This is a delayed a.v.c. system any repair job the bias because = 20 X .26951 resistor in the cathode circuit of both quickly and efficiently, a.v.c. tubes makes the cathode with good profit = 5.4 decibels approximately tive of the 6H6 posi- with respect to the diode plates. Therefore, to himself and complete satisfaction to The effects of Ca by itself can be studied a minimum signal of a given value applied to has to be the customer. from Figure 4. Formula (3) is an expres- the diode plates before the system Let us send you full data sion for begins reducing the sensitivity of the receiver. the loss due to this shunt capacity. It will also be seen that some on WESTON radio service instruments. tubes of the controlled Decibels loss due receive only a portion of the a.v.c. voltage only 1 Weston Electrical Instrument while the first r.f. tube has the total a.v.c. voltage Corp., 615 to shunting effect of Ca f - applied to its control grid. Frelinghuysen A 6C5, Ave., Newark, New Jersey. coca Z Zb is used as a heterodyne beat oscillator. Then there is another extra 6C5 10 log 1 + (3) the dimming pilot which operates light. The rectified signal in Z ± Z,, the diode circuit of the 6H6 second detector applied to the grid circuit is It serves to illustrate signal of this 6C5. When a the amount of Ca is being received, this grid will that can be negative with respect become tolerated in cases where a to the cathode, thereby in- definite value creasing the plate- resistance of can be assigned to Z,,. Sup- connected the tube which is pose we have the following across the d.c. winding of the saturable case: reactor. This has the effect of increasing Z' = 500 ohms reactance of the a.c. winding the with the which is in series Z., = 100,000 ohms pilot light. Therefore, the pilot light dims when a signal is tuned N2 = 200 dial in and the main should be adjusted for the dimmest light. Model 698 low price Ca = 200 mmfd. A 6J7 tube is employed tween stations. to reduce noise be- Selective Set Serv- J = 10,000 cycles This system is in operation only on the broadcast band and on icer, complete with Reducing our value of Z:,' to its band. the long -wave corre- It is really an automatic tone control Socket Selector sponding value for a unity ratio which places a tube in series Set, trans- When with the condenser. leads, carrying former, we have a signal comes in, the tube grid becomes case, negative, increasing the plate resistance etc. Z =Z,'N' tube which has of the the same effect as turning the = 100,000 ohms tone control so as to receive high notes. no signal is coming When Now, substituting in, the plate - in Formula (3) and tube becomes resistance of the cancelling before considerably less and the tone squaring any terms gives control becomes effective, thereby us: and other noises. reducing hiss FESTON Two Decibels loss = 10 log [1 -I- (.628)2] 6C5 tubes are employed to change adio signal from a single -ended amplifier the Inr/rumen/i 10 log 1.3944 into a push - = pull amplifier. These tubes feed into driver tubes, two 6F6 WESTON ELECTRICAL = 1.44 decibels approxi- connected as triodes which in turn INSTRUMENT CORPORATION mately excite the final amplifying stage consisting 615 Frelinghuysen Avenue, Newark, N. J. six 61'6 tubes in a push -pull of Formula (3) by itself is parallel circuit. Send bulletin on inadequate for These tubes are also connected as triodes. Weston Radio Instruments. predicting the high -frequency The power supply response of employs three different recti- Name line -to -grid transformers fiers. Two 5Z4 tubes are employed for the following the power to supply reasons: for the output stage while a 5Z4 is used to supply power single Address 1. Zb is practically The to the other tubes. equivalent to an audio system employs three speakers, open circuit. one low- frequency speaker and City State quency speakers two high -fre

www.americanradiohistory.com NEWS FOR MARCH, 1936 568 RADIO Fewer service call backs on TUNG- SOLtubes...because they're WHAT'S NEW IN RADIO set and circuit tested before wILLIAM C. DORF they leave the TUNG -SOL factory. tester manu- (Continued front page 521) Chekatube Model C111 tube factured by the J -M -P Manufacturing A Giant Filter for Power Jobs Company, Inc. Silver contacts are used on all selector and lever switches. The trans- The Tobe Deutschmann Filterette rated at 50 kilowatts, is of the inductive -capacity type and contains heavy -duty inductances designed to carry the full load current of

former employed has a high -voltage secondary and rectified current is provided for all tests, affording a closer approach to normal operating conditions than is obtained in more common designs. Short - circuit and leakage tests of high sensitivity are provided. All tests are quickly and conveniently made with self- resetting lever switches. Crystal Microphone TUNG1SOL Sound engineers will be interested to hear of the Shure model 77E desk type radio crystal microphone, designed to meet the e0-,a qbuy high -fidelity requirements of public ad- TUNG -SOL LAMP WORKS, INC. Radio Tube Division SALES OFFICES: Atlanta, Boston, Charlotte, Cleveland, Chicago, Dallas, Detroit, Kansas City, Los Angeles, New York. GENERAL OFFICE: Newark, N. I. You Can Become a Fast, Capable RADIO OPERATOR at Home a 50- kilowatt machine without introduc- drop. This The CANDLER SYSTEM Makes it Easy for You! ing an objectionable voltage If you want to learn code QUICK ask about Junior filter was installed in connection with speed ask about type Course for beginners. If you lack a motor operating the vacuum cleaning -HIGH SPEED TELEGRAPHING. Whether comparative Beginner, Amateur or Coni l op., tell plant of a large hotel. For us what ticket you're going up for and size a small junior Filterette is shown in well show you how EASY it is to get. the photograph. CANDLER SYSTEM gives you Speed, Accuracy and ability- to Copy A New Call System Behind -shows you how to use "mill" in copying fast stuff. An inter -communicating system of wide All questions answered. Save time adaptability for office and factory execu- and money by sending for 1936 called the Selective Speech Relay, is BOOK OF FACTS. Contains valuable tives, information. now being manufactured by the Turner station, which is CANDLER SYSTEM CO., Dept. N -3 Company. The master a small cabinet to be placed ASHEVILLE, N. C. contained in on the desk, is provided with push- buttons dress, broadcast and sound recording Beginner or old timer, to be for each branch station. One or more systems. Its associated remote pre- ampli- branches may be simultaneously called, fier is enclosed in a telephone style wall a good operator, you need: which is of great advantage when it is de- box, which can be mounted in any con- Or location. MAC KEY @ $7.91 finest semi- automatic Rey built. venient JUNIOR DIODE.L @ $4.9" a low priced 'speed key- 1,000 Switch guaranteed ; MAC OSCil`ia Radio Time cycles code practice. \TOiteJ $1.95 UAC /De money back guarantee. Herewith is an illustration of a portable Time" switch manufactured by M. T. R. McElroy, 23 Bayside St., Boston, Mass. "Mark- H. Rhodes, Inc. This switch contains a

modela Ma,, to select from, AC-DC, All-wave, Car d ne Tube ì1ód,1,. Your n and ,.jdrees on Postcard brin,, you NEW 16-page 1936 Bargain Cata- log in mio,, FREE. Cu de- ;aile of 30-Der TR.173.1811T and Agent -Leer proposition. Goldentone Radio Co.,Dept.243, 8780 Grand River. Detroit. Mich. whose whereabouts Correspondence Courses In sired to locate a person are unknown or to issue a warning in case RADIO and £L£CTRICM. f NGIN£f RING of fire, accident or other emergency. The give IELECTRICAL ENGINEERING. e a, system is ruggedly constructed to trivet field. Most modern course. So eimottfied anyone oan operation. gran. untidily. Prepares you for secure future. LOW COSTI efficient, trouble -free ENGINEERING á öto= °' $l n: RADIO 1,1 áió wt Diploma you to be super-serviae in. real vacuum tube teoholoian. A New Tube Tester either Deferred payment Plan. by setting the time. Gour cop's of high -grade clock which is wound toge. r magazines', engineering and soih ten Thorough unit will turn on or off any radio set F R a Ë construction are salient features of the new The É Nebr. Lincoln Engineering School, SS7 -E So.37th St., Lincoln.

~~www.americanradiohistory.com RADIO NEWS FOR MARCH, 1936 569~~

or electrical appliance at the desired time. i.f. stages and the conventional glass tubes It can be set up to 12 hours in advance. in the less critical positions. It has a fre- THESE SPLENDID A New Socket for Acorn Tubes The illustration below shows the Ham - marlund Isolantite socket for the ultra BOOKS high -frequency Acorn tubes, types 954 and FREE

955. The socket has five double -grip prongs of tinned phosphor bronze. It measures 17/8 inches in diameter and has an alignment plug to insure proper insertion of the tube. quency range of 535 kilocycles to 18 mega- New Capacity Meter with Four cycles. A mechanical band -spreading ar- Ranges (Turn to page 574) This Weston model 780 multi -range capacity measuring instrument provides full scale ranges of 10; 1.0; and 0.01 Electron Tubes

~~(Continued from page 557)~~

He asserted that, while it is improb- able that all of the functions now performed by the thermionic tube will be replaced by this new cold- cathode device, it was evident to those who have worked with secondary electron multi- plication that this new art will have a revolutionary effect on the science of radio communication. Noiseless amplifi- THINK of it! 2 books full of in- cation was claimed for the "multipactor." valuable information, That to be had the tube is not limited to tele- for just the mailing costs! One with vision application was emphasized by the 20 complete transmitter designs inventor. He said there were many quite including 12 tested transmitter RF unexpected new applications. It was de- section designs and clared 8 modulator that "multipactors" may be used and speech amplifier designs. Cir- as a source of electrons for purposes cuits, complete parts specifications, other than amplification, this being due inductances, etc., all included. Out- to the very high multiplications obtain- puts ranging from a little fellow able. all the way up to the big ones comparable to the best broadcasters. microfarads, thus covering all capacity Ten complete designs for public ranges that are commonly employed in address amplifiers in the other radio sets. It is a.c. operated and mea - "Backstage" book. It includes one for every pur- sures 5% by 334 by 2% inches. pose, from 3 Wafts to 30 Watts page (Continued from 551) output, tried and tested designs Special Speaker System that you can build, with complete One The Pacent high- fidelity speaker system of the choicest juvenile roles in the parts list for each. films went to Billy Mauch, 10 -year old consists of 2 dynamic cones for low re- These dramatic actor heard on many books should be in every sponse and a dynamic tweeter for high -fre- CBS and amateur's technical NBC programs. He was signed by library. They quency reproduction. The speakers are are invaluable for reference Warner Brothers to portray the role of purposes. Just 22 "Anthony Adverse" as a boy- Fredric cents in stamps, to March will portray the adult character. cover postage, brings them both to you, or get them from Billy's twin brother, Bobby, also a radio any standard star, accompanied him distributor. Send for your copies to the West Coast. today. A Twentieth Century -Fox contract recently was awarded Helen Troy, diminutive comedienne who portrays Susie on NBC's STA -N DARD Saturday Carefree Carnival. Carol Deis, co- featured with Conrad Thibault on the TRANSFORMER Log Cabin Revue over NBC, Wednesdays, is another radio star making headway in the talkie field. CORPORATION ( nnected to operate as a single unit and 856 Blackhawk SI., Chicago, Illinois have their own power supply. IN selecting Louis Gress as permanent conductor for his Sunday CBS broad- Easily Installed Sound System casts, Eddie Cantor has brought a new VIRIL THIS [OuPOD! The Remler public -address system fea- name to stellar radio ranking. For the tures easy installation and operation. In start of his new season's Pebeco programs, addition to the amplifier the system in- the comedian used a different guest con- f STANDARD TRANSFORMER CORP. ductor every cludes a floor -stand condenser microphone, week, but he soon decided Dept. D. 856 Blackhawk St., Chicago. 2 tone -equalized speakers and the neces- to pick a permanent musical setup. Gress and ! am enclosing 12c for Transmitter Manual sary connecting cables, plugs, etc. It is Cantor previously worked together in stage productions. available for either 110 volt alternating. Gress, a native New I am enclosing IOc for Amplifier Manual current or battery operation. Yorker, conducted three editions of the Ziegfeld Follies and Cantor's starring ve- Name Features Three -Band All -Wave hicle "Kid Boots." Supplementing his instruments Tuning for tonal effects are bottles, IAddress I glasses and megaphones. He also employs The Belmont 7 -tube receiver employs eight voices to produce sounds and tones [ty State the metal type tubes in the r.f., mixer and in addition to song lyrics. taaa' aaaas arse aaaaa sass asaa:.

www.americanradiohistory.com FOR, MARCÍI, 1936 570 RADIO NEWS Service eApplications of the Super-Sensitive V. T. VOLTMETER (As described in the August, October and November, 1935, issues) By John H. Potts Part. Four

FFICIENT servicing of sets afflicted avoided until the defective stage is iso- with intermittent fading conditions lated. In making the above tests, there is constitutes one of the most difficult less reaction on the set if the coupling is problems facing every serviceman. Many made from plate to plate rather than from have been proposed for handling grid to plate. In i.f. stages, one may couple methods detuning FEATURING such troubles. All work in some cases; from grid to grid without serious none in all cases. due to the high sensitivity of our tube PUBLIC ADDRESS! Usually, abrupt intermittent fading is voltmeter, which requires relatively little Let Lafayette engineers tell you how to get a mechanical or electrical coupling with even the ordinarily low out- this summer. The caused by poor into this lucrative field contact in some portion of the set or its put voltages given by the average service season of conventions, athletic and out. oscillator. With a superheterodyne re- door social events is at hand. All need associated equipment. When the trouble Lafayette Public Address. Our proven. is purely mechanical, often little difficulty SHIELDED LEAD busioess'getting plans are used by radio is in locating the cause. But f5,000 4000 experienced OHMS, OHMS service erywhere. Consultation when the trouble is induced by heat ex- without obligation is invited. FREE Catalog pansion and occurs only when the chassis describing complete line of Equipment and is tension or enclosed in a cabinet, V request. under .05 accessories on obviously trouble -shooting is rather dif- .z5V Address Dept. N.36. rarely occurs under 1.0V. ficult. Gradual fading 5.0V. _ 4000 conditions and is ordinarily far easier I- OHMS RADIO such D 40.0V ' WHOLESALE CO to handle. Some other causes of gradual a 080,000 z OHMS " OE ALE N.Y.SERVICE fading, such as leaky coupling condensers loo SIXTH AVE. give 400,000 or plate resistors changing under load OHMS FIG.2 CHICAGO. ILL. ATLANTA, GA. a characteristic sound in the speaker read- 901 W. JACKSON BLVD. 431 W. PEACHTREE ST ily recognized by experienced radio men. BRONX.N.Y. NEWARK.N.J. fad- 542 E.FDRDRAMRD. 219 CENTRAL AVE. In the more difficult cases of abrupt ceiver, for instance, simply bringing the ing, even touching a test prod to the chas- tube voltmeter test lead near the oscillator c9isésste yostvt.SisccelJ sis will often temporarily restore normal condenser gives an immediate indication operation. Such conditions are frequently if it is functioning. caused by by -pass condensers which de- test National Schools, Los Angeles. The design of the capacity coupling otter full inetruction in Elec. velop intermittent "opens." The super- tricity, Television, Radio, prods will depend on the oscillator output Talking Pictures and Com- ìal d Br adc tOperat- available. With some service oscillators, ing.C National's all- inclusive so cou qualifies you for a suc- ELECTRICITY sufficient output may be obtained that cessful. profitable future will the actively growing fields a only a short piece of insulated wire Electricity, gRodio d leS- TELEVISION With others a ná mgarte uTe. . provide enough coupling. cuvt.' hceen Earn room and board while 1 -inch metal plate, or even a small coupling learning. Coach R. R. fare showed to L. A. &RADIO coil, may be required. MAIL THIS COUPON An attenuator, to adapt the tube volt- up to 10 volts at NATIONAL SCHOOLS -LOS ANGELES meter to measurements Dept. RN -3, 4000 Figueroa St. 20,000 ohms per volt, is shown in Figure 2. will be accurate only at low NAME The ratios frequencies, up to about 20,000 cycles, but ADDRESS it will be found quite useful in testing CITY STATE public-address amplifiers, pick -ups and pre- L amplifiers.

Use Genuine PREMAX MASTS Radio Workshop aerial to go sensitive tube voltmeter, used in conjunc- When it's an 532) up, stop messing around tion with a test oscillator, permits the stage (Continued from page with gas pipe or 2 x 4's. affected to be quickly isolated without Premax Telescoping Steel snaking a metallic contact to the chassis. is the use of a Yaxley rotary switch with Masts save time and pa- set -up shown in Figure 1, the a single deck of eight points or one with the Using the tience, yet cost about oscillator is coupled to the input circuit a double deck, four points each. same as pipe. At your a special NOEL CHASE, Bul- of the stage under test through dealer or write for test prod and the tube New York, N. Y. letin RN. capacity coupling voltmeter similarly to the output circuit. SALES DIV. Sufficient oscillator voltage at the frequency Two Soldering Kinks PREMAX is to to which the circuit is tuned applied pro- Chisholm -Ryder Co. deflection on the tube volt- Strange to say, few irons have been give a good attached. The one shown Niagara Falls, N. Y. A comparison reading is made of duced with a rest meter. Figure 1, is similar to the a similar stage. If either of the condensers in the diagram, are defective, a far higher os- folding rest on a carving fork and can be Cl or C3 time from odds and cillator input will be required than that constructed in a short JOBBERS SERVICEMEN for a similar stage with good by -pass con- ends of hardware. trimmers and transformer Make a band to fit around the iron, from Write for FREE 1936 Catalogue! densers. Shorted below with a will likewise show up by this test, flat brass and clamp together Covering Replacement Parts Ham defects stiff wire bend the - Parts Amplifiers latter may be readily located with- small bolt. Then from Parts Short Wave but the The legs spread out and Kits Experimenters Parts Ac- an elaborate set -up. In all fad- rest as shown in detail. out such eyes fit around cessories. cases, the use of analyzers, volt -ohm- at the bottom and the two COMPANY ing them serv- BOND RADIO meters or condenser testers should be the bolt; the cross bar between 11702 Livernois Ave., Dept. 211t, Detroit Mich.

~~www.americanradiohistory.com RADIO NEws FOR MARCH, 1936 571~~

ing as a stop bar when the legs are in a replacement unit are to be connected. vertical position. This bar straddles the If an exact duplicate replacement part clamp and the eyes go between the clamp is used, one need only replace the old leads and washers as shown. By using lock washers the tension can be regulated and held by the tension of the nut on the bolt. Thus your iron can be rested above the OP bench or the rest folded back against the shank when not in use. String solder wound on spools is awk- ward to hold and it is much easier to rack

~~"""""No 1 SUPPORT~~

~~STOP, X= CLIP AT THESE POINTS~~

with each new lead having the same color coding, one by one. If a different replace- Model 710 -A ment part is used, the slip accompanying FIG.4 same will enable one to identify the corresponding lead. DEALERS° W. D. PAYNE, it, as shown in the little holder in the Buffalo, N. Y. NET PRICE sketch, Figure 2. Take a piece of suitable copper tubing about 8 inches long and split Polishing and Cleaning Old down one end, for a third of the distance Bakelite Only 16° with a hack -saw. Open this split and drill The following information the ends. Then insert the was received spool of solder from Mr. Allan Brown of the Bakelite and hold it with a metal pin inserted in Cor- ALL the poration in reference to an item entitled CHECKS PARTS OF holes in the ends of the prongs. "Renewing the Appearance Bakelite Run the solder through the tubing of and until Hard Rubber Parts" which appeared in the RADIO CIRCUITS USING it projects from the end. By wrapping the Experimenter's Department. "We have carried on a number of ex- GLASS OR METAL TUBES SPOOL OF STRING periments and recommend the following: SOLDER To keep a panel in good shape sponge it off This popular three meter set tester checks all parts with alcohol occasionally. The only dirt that of radio tube circuits by plugging directly into sticks is greasy dirt, like the receiving set sockets. WIRE 1111111111111111111 fingerprints, and these could be washed off PIN with alcohol D.C. Voltmeter better than they can with soap Scale 20.60.300 -600 and water. D.C. Milliammeter If a high lustre is desired Scale 15-150 on a polished A.C. Voltmeter surface, a little Butcher's floor wax may Scale 10-140-700 SPLIT be applied and rubbed; or with dull panels, Model 710 -A INTO .._COPPER"r where FORK TUBING a rich matte finish is desired, a little In Black Leatherette Case complete with all light lubricating oil may be wiped on and necessary connections. then carefully rubbed off. Dealer Net Price $16. 0 A Simple Vacuum -Tube Model 712 -A Same as 710 -A but having Triplett moving coil Voltmeter Model 223 2" D.C. Voltmeter (1,000 ohms per volt). SOLDER Here is a diode -type vacuum -tube volt- Dealer Net Price 422.20 meter that can be used for a wide variety of tests, where a slight circuit load is not objectionable. Being substantially independ- OTHER FIGURE 2 ent of frequency it is adaptable to either READRITE a.f. or r.f. circuit. PRODUCTS tubing with a layer of electricians' Readrite also manufactures tape or The value of R1 will depend all types felt it can be used as upon the of testers used for servicing radio the solder holder in sensitivity desired. For full -scale sets, including: lengthy jobs without the heat of the solder deflection Set Testers, Tube with 100 volts input the value of this Testers, Oscillators, Resistance, Con- being imparted the tinuity and - to hand. resistor should be about Capacity Testers, Point L. B. 75,000 ohms. For to -Point Testers and inexpensive In- ROBBINS, greater sensitivity RI can be decreased dicating Meters. Harwich, Mass. so Overcoming Refrigerator Interference Quite often radio interference can be traced to static discharges from the motor belt of electric refrigerators. To eliminate this type of interference simply connect a wire from the motor frame to the com- pressor and continue this lead to a good ground. ELWOOD S. FAULS, MAIL THIS COUPON Oneida, N. Y. Readrite Meter Works Identifying Replacement 315 College St., Bluffton, Ohio Connections Please scud me more information on: In replacing transformers, condenser .. Model 710 -A ...... Model 712 -A blocks, and similar parts with numerous New Catalogue leads, the problem of reconnecting the as to cover any desired range. The device wires to the proper points may be greatly has a fairly linear scale and it may be Name simplified and a great deal of time saved calibrated on an a.c. 60 cycle supply line if the old leads are clipped off close to by connecting it in parallel with an a.c. the defective component. meter. This calibration will hold for radio Address After the defective part has been re- frequency as well as audio frequency. moved, the color -coded loose wires remain- JOHN POTTS, City State ing will indicate where the leads from the New York City, N. Y. 1. J

~~www.americanradiohistory.com 572 RADIO NEWS FOR. MARCH, 1936~~

of the stations operating in the lower half of the the IMPOSSIBLE The Shack band, that is, from 28,000 to 29.000 kilocycles. "Ham" Therefore, a number of amateurs who have undertaken to construct special receivers for 10 -meter is a REALITY- (Continued from page 527) operation have designed them to cover the lower 1,000 kilocycles on 180 degrees of tuning. This the Amazing partly solves the sharp -tuning problem, but after the sun -spot activity which causes leaves the high- frequency half of the band un- DECOSTER this additional in- covered, and with the increasing number of sta- WRIGHT- them. Therefore, with tions using the band, it is desirable to make use fluencing factor, the problem of predicting of the whole band. Two band -spreading settings conditions is made more difficult. might therefore be built into the special 10-meter receiver, one for the lower and one for the higher NOKOIL transmitters for 10 -meter Now, about halves. operation. A number of the 20 -meter The super -regenerator receiver that performs DYNAMIC REPRODUCER good" 'phone men have found it possible to op- so well on 5 meters has been found "not too on 10 meters. Its broad tuning characteristic is erate their rigs on the higher frequency not particularly desirable when listening to with reduced inputs with effective results. crystal -controlled signals. have As we have already said power on 10 On the other hand, a number of amateurs obtained quite good results with 5 -meter super - meters seems to be one of the least impor- heterodynes, equipped with 10 meter coils. Those tant factors. Good results may be expected with transformer -type intermediate circuits are 100 input. The chief the best for selectivity, of course, although re- from 50 to watts sistance-coupled i.f. circuits will give excellent problem in getting a transmitter operating gain at this frequency. If a special receiver is on 10 meters is obtaining sufficient excita- used, it will be found that good results will be of the stages. obtained by using an intermediate -frequency of tion for each the order of 2,000 kilocycles. Several amateurs Several suggested layouts are illustrated have constructed adaptors for 10 meters and are here. Each of them have been in use at working them into autodyne receivers tuned to "All that the name implies " 2,000 kilocycles, and are obtaining exceptionally different Eastern amateur stations and have good results. The autodyne receiver is simple to ±t40 FIELD COIL OR CURRENT+ provided excellent results. The one which construct and easy to operate, and provides good seems to provide the greatest all- around sensitivity, but does not usually compare with a good standard superheterodyne. However, 10- Performs like an electro- dynamic re- stability and effectiveness is that shown at meter reception is more susceptible to ignition producer Figure 1. It is a conventional layout. interference than the lower frequencies, and in Requires less space than an electro- The tube line -up is a 53 used as 40 -meter locations where automobile traffic is heavy, it dynamic speaker will be found that the autodyne may out -pertorm oscillator -20 -meter doubler ; an 802 for the superheterodyne. Priced to compete with electro- dynamic doubling into 10 meters and an 800 type Returning to the subject of transmitters, due reproducers- tube in the final. It wgs possible to run to the sharp tuning effect of the receivers used a com- on 10 meters, only crystal -controlled transmitters The answer to the demand for up to 100 watts input in the final ampli- should be used. They, of course, will hold to pact permanent magnet dynamic types will be more speaker fier with a high degree of efficiency. their frequency, while other about rig might apt to drift and shift in frequency, making it A few points this particular difficult the operator on the receiving end to Available in 6" and 8" models be interesting. The 53 oscillator -doubler is being for on the 20- hold on to a signal. Write for complete catalog, prices and used by a majority of the stations covers the problems of band, and therefore, a large number of This in a general way name of nearest distributor. Wright - nieter 10 -meter operation. It is hoped with the in- s of equipment available. DeCoster distributors are always anxious tations have this portion activity, more will be learned about the With a 40 -meter crystal, it is possible to get creased to cooperate. any other band, and just what may be expected of it. As more output on 20 meters than with good DX oscillator. The output is more than suffi- we said before, in addition to providing type of it is an excellent WRIGHT- DECOSTER, Inc. 10 meters with as high possibilities, also band for local cient to drive the 802 on communication. 2255 University Ave. St. Paul. Minn. as 5 milliamperes rectified grid current, the nor- Export Dept. -M. Simons & Sons Co., New York mal rating suggested by the manufacturer. ' Simontrice" Cable Address 600 volts Calls Heard Canadian office-A. M. FlOnechtheim & Co., Guelph, With normal input on the 802 (about t. with 60 milliamperes) it was possible to drive the By Norman C. Smith, Forge House, High 800 with 25 milliamperes grid current, with nor- Street, Foots Cray, Kent, England, on 40 -meter mal bias. If more power were to be desired on 'phone: LU8DR and TI2EP. 10 meters, an additional amplifier might be EA6AM, LU1EP, HB9AQ, On 40-1et r CW: added. However, at 10 meters, it will be found ZL3DJ, W4UP, EA2JJ, ZL1HY, ZL2FY, that the low- capacity tubes such as the 800, 50 -T, VK2BV, VK2PT, VK2ZC, W4AXA, OX4VDB, 852, 150 -T, RK -18 and RK -354 will provide the VJ3JO and XD4BOZ. greatest efficiency. The higher capacity tubes By T. E. Lowe, 28 Allenby Road, Cadishead, may be used, but it will be found that reduced M /C, England, on 20 -meter 'phone: W2HMY, inputs will be necessary to avoid excessive heat- W2BS, VE9DT, W4DGC, W1GND, W2FDW, LINE ing. The radio -frequency current does curious W2DSD, W2AMD, W1CND, AV2YD, WSCFT, things at these high frequencies. At one station W1CMD, W4CDC, FSFU, W1AF, SN5WK, TEST where a 203 -A was used in the final amplifier W2AN, W4DB, W3COV, FSNH and W2BSD. pmEnT with reduced input. The tube showed excessive TUBE heating despite an apparent high plate efficiency, RADIO NEWS Sponsors New slot i.e., ratio of power input to power output. How- U defects ever, the tube elements ran exceptionally hot, Opportunity for Code demonstrates tests. freak effect of the radio - th tubes , soeCifiic apparently due to some Practice at Home that sells x different, frequency current. Such a condition is not good easily ' - in a short life. Ply and for a tube and will result RADIO NEWS takes pleasure in publish- Another suggested layout is shown at Figure a ing the following schedule of code trans- 2. It consists of a 59 tri -tet oscillator using especially for 40 -meter crystal, with the output tuned to 20 missions in the United States meters, a 46 amplifier, an 841 doubler and an those who wish to learn the code over the 801 in the final. This arrangement proved quite air. All one has to do is to tune in to the effective with 50 -watts input to the 801. Figure proper frequency as specified at the proper A third suggested layout is shown at day and start copying the spe- 3. This consists of a 53 oscillator, quadrupler, time and a 46 buffer and an RK -20 amplifier. By using cial code transmission for practice. A regeneration in the 53 amplifier -it is possible daily schedule is given for the present to obtain sufficient excitation to drive the 46 at February 1st and end- low input in 10 meters. Of course, the output month (beginning from the 46 will be sufficient to drive the pentode ing March 1st.). In the first column is final amplifier on ten meters, as 5 milliamperes the time (am. or p.m.) ; in the second col- grid current is more than sufficient to operate symbols, E, C, M and P this tube at normal input. A high c.w. output umn are the and a 15 to 20-watt carrier, with suppressor grid (where E is used for E.S.T., C for C.S.T., modulation, may be obtained. M for M.S.T. and P for P.S.T.). In the Receivers for 10 meters are another problem. third column are the call letters of the Few of the all -wave receivers that perform ex- of amateur members of the ceptionally well on frequencies of 14,000 kilo- transmitters cycles or lower are proportionally as efficient on Guild and the fourth column contains the 10 meters. Some will give satisfactory results, frequencies of transmission in all cases, ex- but the chief problem on 10 meters is that most where otherwise noted. Each CSCG all -wave receivers tune so many kilocycles per cept dial division that only very careful tuning will transmitting station will begin his program reveal signals. Ten -meter signals seem to be at stated time by sending "CSG" 6 times, lower frequencies. much sharper than those of followed by his station call repeated 3 This, of course, is only apparent, as it requires only a small amount of capacity change in an times, slowly. At intervals of 5 minutes, L.C. circuit to cover several kilocycles, with a he will repeat "CSG" 6 times and his call result a far greater degree of band spreading is lower frequencies. letters 3 times. All who listen to CSCG necessary than available for a In receivers with changeable coils, the band- programs are requested to write card to spreading problem is simplified by the fact it is the transmitting station telling him how his possible to change the tuning ratio more in keep- signals come in and, if possible, sending ing with the frequency. The 10 -meter band, however, covers 2,000 kilocycles, and even with a him copies of transmissions. receiver designed to spread the whole band over a 180 degrees of a dial, tuning will be found MONDAY to be exceedingly sharp. This tuning problem has resulted in a majority 8:30 A. E. W1AMH 56,100- 3536jy

~~www.americanradiohistory.com RADIO NEWS FOR MArcx, 1936 573~~

9:00 A. ED. W2HZ 1 3577 W5DDC- Herbert Leo, 1420 Hawthorne St., 10:00 A. E. \\'3AEJ 3785 Houston, Texas. 4:00 P. E. NIFNM 3510 W5CPV- Grady- L. Hardin, 132 Oak St., Hot 5:00 P. P. W7WE 3637-7274 Springs, Ark. 6:00 P. E. W8MHE 3830 6:00 P. E. VVSEEZ 3598 \V6IQY -E. L. Troutman, Box 55, Flagstaff, 6:30 P. C. \V9LKK 3757 Ariz. 6:30 P. E. N1DUZ 3638 W7WE- i.oren C. A[aybee, 3516 Hudson St., 6:30 P. E. W2HCP 4785 Seattle, Washington. 7:00 P. C. W9SFT 3585 \V7DBP -F. \V. Stuart, R. F. D. 2- Boise, TORSION GRIP 7:00 P. E. VV8NL'O 7250 Idaho. 8:00 P. E. WBMCP 3580 W7D \VI -R. J. Gunning, Wendell, Idaho. W8HKT -F. T. McAllister, 807 Michigan MAKES TUESDAY Ave., St. Joseph, Mich. 8:15 A. E. \'E3UU 3865 W8MCP-Chas. Hedrich, 30 DeKalb St., PERFECT CONTACT 9:00 A. ED \\'2HZJ 3577 Tonawanda, N. Y. 4:00 P. E. N1FN\I 3510 W8MHE- Charles L. Gibson, 9 Sycamore St., The new socket for 6:00 P. E. W8MHE 3830 Natrona, Pa. the new tubes 6:00 P. E. \V8EEZ 3598 WSEEZ -Tauno M. Alanen, 512 New Street, -metal 6:30 P. C. \V9LKK 3757 Fairport Harbor, Ohio. or glass. The prongs 6:30 P. C. W9RPD 3514.5 VVSKGM-E. J. Goodison, 300 E. Edward St., of tubes are gripped scissor -like, in- 7:00 P. M. W9HHW 7276 Endicott, N. Y. suring absolute 7:00 P. M. \V6IQY 14380 contact and eliminat- 7:00 W8NUO-J. A. Ditmyer, 2541 Kress St., ing noise, squeals, cracking, or P. E. W8NUO 7250 Ohio. any 7:30 P. C. W8HKT 3750 Toledo, irregular W9HHW- Denzel Begley, Box 46, Ft. Meade, reception. Contacts made of 8:00 P. C. W5CPV 7149 grade "A" Phosphor 8:00 P. E. W8MCP 3580 S. Dak. Bronze 8:00 P. M. W7DBP 3607 W9RPD-R. J. Lawrence, Fort Lincoln, ... the finest conductor . . . 8:15 P. M. \V7DWI 3620 N. Dak. rust and corrosion proof. \V9SFT-Gerald Broughton, CCC Co. 735, Lasting spring ac- WEDNESDAY Scammon, Kansas. Sidney Schulz, 3132 -4th St. S. E. tion ... constant 6:00 A. C. \V9LKK- \\'5DDC 7200 Minneapolis, Minn. Torsion Grip . . 9:00 A. E. \\?HZJ 3577 Read, 3401 Parnell Ave., I0:00:\. E. \\'3--\ EJ 3785 \V9LUS- Clarence extended lug for 4:00 P. E. N1FNM 3510 Chicago. fast soldering ... 5:00 P. P. \V7WE 3637-7274 wrapping grooves 6:00 P. E. W6\1HE 3830 6:00 P. E. W8EEZ 3598 for quick testing and assembly. 6:30 P. C. W9LKK 3757 Perfect contact means perfect reception. Tor- 6:30 P. C. W9RPD 3514.5 sion Grip insures this. There is no Grip like 6:30 P. E. W2HCP 3785 Torsion Grip. Order a supply today. 10¢ 7:00 P. E. \V3AE.1 3785 each . .. or $1.00 per dozen postpaid. 7:00 P. C. \V9SFT 3585 7:00 P. M. \V91-IHW 7276 Armstrong's Invention HMINHAtHH HHHH®1HHIHNI 7:00 P. E. \VSNUO 7250 8:00 P. M. W7DBP' 3722 (Continued front page 525) TORSION GRIP MFG. CO. 408 S. Hoyne Ave., Chicago, Ill. Enclosed you will find f for THURSDAY presence of the carrier). The point to be noted which you will please send Torsion 8:15 A. E. VE3UC 3865 is that only the noise originating within, say, Grip Sockets. 9:00 A. E. \V2HZJ 3577 10,000 cycles -per -second to either side of the 4-prong. 5 -pr. 6 -pr. î-pr. S-pr. 6:00 P. E. \VS\IHE 3830 carrier can produce an audible beat with the 6:00 P. E. \V8EEZ 3598 carrier in the audio -frequency circuits. Beats 6:30 P. C. \V9LKK 3757 are also produced by noise originating more than 6:30 P. C. W9RPD 3514.5 10,000 cycles -per -second from the carrier, but 7:00 P. M. W61QV 14380 these are inaudible and, in fact, will not be NAME 8:00 P. M. \V7DBP 3607 passed by most audio channels. The noise orig- 8:15 P. M. \V7D\VI 3620 inally present and distributed over the entire ADDRESS 100 -kilocycle band -width will still be present, but FRIDAY this noise is greatly overshadowed by the noise introduced by the addition of the carrier. TOWN STATE 10:00 A. E. \\'3AP.J 3785 Referring to Figure 8, it is seen that the 9:00 A. ED. W2HZJ 3577 principal noise components, as introduced by the 5:00 P. P. \V7WE 3637 -7274 carrier, occupy a band only 10 kilocycles to either 6:00 P. E. \V8\1HE 3830 of the or 20 kilocycles in all. In 6:00 P. E. WSEEZ 3598 side carrier, P. addition, as mentioned before, the current limiter 6:30 E. NIDUZ 3638 has introduced a "mirror- image" frequency for 6:30 P. C. W9LKK 3757 each disturbing frequency present in the output 6:30T. E. W2HCP 3785 of the amplifier. If a noise component, for ex- 7:00 P. E. R'8N UO 7250 is 9:30 P. E. \V4BHR 3867 ample, of 410 kilocycles present in the input to the current limiter, the limiter introduces a. companion frequency of 390 kilocycles, and so SATURDAY on for each disturbing frequency. The action of 6:30 P. C. W,5RNA 3610 the current limiter is such that when the two 8:15 A. E. VE31-t- 3865 disturbing frequencies are co- linear with the 8:30.\. E. \VIA\1H 56,100-35363 carrier, they are opposite in phase. 9:00 A. ED. \V2HZ1 3577 In the position shown in Figure 8, with the 6:00 P. E. AV8\IHE, 3830 carrier at 400 kilc,cvcles and the disturbing fre- 7:00 P. E. \VBNL'O 7250 quency and its mirror image at 410 and 390 kilo- 11:50 P. P. \V7\VE 3637-7274 cycles respectively, the response clue to the 410 and 390 kilocycle signals are equal and opposite (when the disturbing signal is co- linear with the SUNDAY Consequently, at carrier). that instant, the noise Servicemen! Sound 6:30 P. C. \V5 BS--\ 3610 components are cancelled, except for the small Specialists! For 8:15 A. E. \'E3UU 3865 amount of noise originally present before the real money -making, 9:00 A. ED. W2HZJ 3577 introduction of the carrier. If the disturbance customer -pleasing P. A. 10:30.-\. E. \V3EEV 3628 components are not co- linear with the carrier, equipment-see your ALLIED Catalog! 10:30 A. C. W5DDC 7200 their effect on the carrier is still small since they Get acquainted with our unbeatable line -5 tc 50 watts -individual amplifiers or complete systems. 11:00 A. E. \V'8KGM 3807 are out -of -phase with the signal, but some of the portable, mobile or permanent -preamplifiers, 1:00 P. P. W7WE 3637 -7274 noise does not balance out. microphones, speakers, phono equipment, record- 6:00 P. E. \VSMHE 3830 Also, the carrier is swinging over the entire ing systems, etc. -Sound for every need! 6:30 P. C. \V9RPD 3514.5 100 kilocycle band, and, even with the noise and FREE CONSULTING 7:00 P. C. \V9I.US 3631 its image in direct opposition. they SERVICE can cancel Write to our Sound Engineering Division for 7:00 P. E. W8\00 7250 exactly only at the 400 kilocycle point. At any sound expert advice on your P.A. problem;. 8:00 P. M. \V7DBP 3722 other frequency a part of the noise remains. We're ready to answer any question, to supply With these effects taking place simultaneously, any ype of Sound Equipment at rock -bottom if the frequency deviation is made wide enough, prices. Write to us: only ALLIED can Active a considerable improvement in give you "Sound" Value, "Sound" Ser- Members signal to noise vice, and "Sound" Prices. ratio obtains, and, the wider the frequency de- Send for Free Candler System Code Guild viation, the greater will be the improvement. Catalog. Dept. M. Armstrong has obtained an improvement W1AMH- Harold J. Morse, 45 Hebron in St., signal -to -noise ratio of something more than 30 ALLIED RADIO Hartford, Conn. d.b., with a deviation of 100 kilocycles, or N1DUZ -J. E. Vermeirer., 137 Middlesex St., a total 833 W. JACKSON BLVD. Mass. band width of 200 kilocycles. Springfield, By reducing the noise inherent to his receiver, CHICAGO, ILLINOIS N1FNM -G. W. V,abrek, New Hartford, Armstrong is enabled to increase the reception Conn. range of his frequency -modulated signals beyond \V2HCP -A. P. Baser, 32 Dove St., Albany, the limits York. of ordinary ultra -high frequency sig- New nals. The amount of static, while very small at \ \'2IIZJ- Walter G. Gerinann, 905 E. 169th these frequencies, is made still smaller by the St., New York, N. Y. noise-reduction process. A. D. As far as man -made RADIO ENGINEERING W3EEY -Dr. H. Baer, BAER HOS- disturbances are concerned, the system is effec- PITAL, Allentown. Penna. tive so long as the signal is somewhat stronger RCA Institutes offers an intensive course of high \V3AEJ -Geo. \V. Knowles. 82 Elgin Avenue, than the noise. If the interference standard embracing all phases of Radio. Practi- Westmont, N. J. is stronger cal training with modem equipment at New than the desired signal then the frequency modu- York and Chicago schools. Also specialized VE3UU- Gordon Murray, 53 Elm Grove lation method courses Toronto, cannot offer any improvement over and Home Study Courses under Ave., Ont., Canada. the usual method of communication. At the very "Noobligation"plan. Catalog Dept. RN -36. \V4BHR -James D. Randolph, Warren Plains, high frequencies, ignition interference is objec- N. C. tionable, if automobiles can approach within, say, RCA INSTITUTES, Inc. WSBSA -H. Trosper, Box 223, AVhittenburg, 50 feet of the antenna. 75 Variek St., New Texas. Other electrical noises York, 1154 Merchandise Mart, Chicago are usually not severe enough to prevent corn- Recognized Standard in Radio Instruction Since 1909. ,

~~www.americanradiohistory.com MARCH, 1936 574 RADIO NEWS FOR~~

munication and, in any event, they can be brought to a level lower than that of the signal by the normal noise- suppression means, with the cure applied at the source of the interference. Profes- sor Armstrong looks toward the complete elimina- GET tion of automobile ignition interference by the eventual use of suppressors and similar devices A SHARE in all automobiles. TATTELITE TESTER Selective fading is not present to any extent In addition, the new Tells the tale -a new pocket - OF THIS NEW at ultra -high frequencies. sizé tool for service men -tests fol system eliminates periodic fading of the common blown fuses, condensers, resistors. PROFITABLE form, if the signal strength does not drop below r.f. peaks, wave length, polarity, Go after the radio the minimum level of the current limiters. In open circuits, live lines, defective business that felr this respect the action is similar to that of an spark plugs and has over 100 more servicemen have automatic-volume -control. It should be noticed uses! Get a TATTE- Complete considered worth- 3147119131 also that interference between stations is mini- LITE from your lob- for a while The elimina- mized. An interfering station, even if it is ber or direct. $100 tion of- static disturb- operating on the same carrier frequency, if its Send 10c for catalog of the power supply and level is lower than that of the current limiters, other Tattetkes, Instrument. prepaid ances in both noise (so far as the receiver is Aircraft and Hip', Volt- with antenna. becomes another age L,ttelfuses, Radie Fuses instrue- concerned) and its amplitude is reduced just as and Mountings. fions Prac- 26,000.000 radios are now in use. that of a noise would be. LABS. require one form or LITTELFUSE tically all of them 4256 Lincoln Ave., Chicago III another of filtering. Here's a slice of business in which there is little competition and a big margin of profit. Cornell -Dubilier has the unit that will do the job for you scientifically! The C -D What's New INDEX TO ADVERTISERS Quietone IF-1 utilizing a properly designed filtering network completely eliminates all from page 569) Aerovox Corp. 552 static. (Continued Alden Products Co. 562 Radio 560, 566, 573 Can be used on either A.C. or D.C. at set Allied Corp. voltages up to 220 volts. rangement is provided and the operates All -Star Headquarters 564 on 110 volt 60 cycle a.c. supply. American Transformer Co. 576 Amperite Corp. 564, 576 LIST $500 PRICE A New Positive -Grip Bond Radio Co. 570 Brush Development Co., The 574 The usual Cornell -Du- Type Socket bilier iron clad guarantee A new spring type socket, known as the Cameradio Co. 575 protects you on this pur- Candler System Co., The 568 chase. Write immedi- Torsion Grip, has just been announced by Capitol Radio Engineering Inst 561 ately for the full infor- the Torsion -Grip Manufacturing Company. Central Radio Laboratories 554 mation. given the prob- Classified Advertising 575 Special study has been to 574 Manufacturers of the world's of on tube Cornell -Dubilier Corp. most complete condenser line. lem securing a tight grip the Cornish Wire Co., The 576 prongs, making for increased efficiency and Coyne Electrical School 575 Deutschmahn Corp., Tobe 561 mo-Im.1VOV-II .{anum i , 11u N Dodge's Institute 564 CORNELL- 11 %/1EIII Mf.i.. 'A=11111111 %f///////// Electrad, Inc. 562 DtiBILIER First National Television, Inc .. 562 C O R P O R A T I O N General Electric Co Inside Front Cover 568 4387 BRONX BOULEVARD Goldentone Radio Co. N E W Y O R K U . S . A. therefore improved performance in tube Hallicrafters, Inc. 556 operation. The contacts are short, grasp- Hammarlund Mfg. Co. 555 ' 559 ing firmly the upper portion of each tube Hygrade- Sylvania Corp. prong. With this design, the usual tendency Instructograph Co. 576 toward loosening contact due to vibration International Resistance Co. 576 BRUSH is completely absent. The socket is of sub- Ken -Rad Corp., Inc., The 576 stantial yet low -loss construction, using high -grade bakelite insulation. Lincoln Engineering School 568 SPHERICAL Littelfuse Labs. 574 A New Antenna Kit for All - Lynch, Inc., Arthur H. 576 MICROPHONE Wave Receivers McElroy, T. R. 568 McGraw -Hill Book Co., Inc. 558 .¢atu7e9 The Technical Appliance "Taco" all-. Mallory & Co., Inc., P. R 518 wave doublet antenna system includes 60 Midwest Radio Corp. Back Cover feet of wire for the top span, 75 feet for 563 Size Light Weight ( National Company, Inc. Small the downlead and the necessary coupling National Radio Inst. 513 National Schools 570 Price and National Union Radio Corp. of N., Y 560 New York Y.M.C.A. Schools 576 Typical BRUSH Sound O'Brien, Clarence A. 576 Cell Precision Apparatus Corp. 553 Operation Premax Sales Division 570 RCA Institutes, Inc. 573 low price microphone RCA Manufacturing Co. 552 A specially designed, Radio City Products Co 553 for remote pickup, "P. A." commercial intersta- Laboratory 572 Uses round case Radio Technic tion and amateur work. the Radio & Technical Publishing Co 554, 557 first introduced by Brush engineers in their Radio & Television Institute 565 expensive laboratory microphone- Wide fre- Radio Training Association of America 566 quency response and typical sound cell opera- Radolek Co., The 575 tion. Non - directional. No diaphragms. No Readrite Meter Works 571 distortion from close speaking. Rider, John F. 551 Easily installed. No button current or polar- Rim Radio Mfg. Co. 560 izing voltage -no input transformers -and no Rotospeed Co., The 558 elaborate stand mountings are needed. Beauti- Scott Radio Labs., Inc., E. H 549 fully finished in dull chromium. Size only 2% McMurdo 515 5 oz. level Silver Corp., inches in diameter. Weight Output Solar Mfg. Corp. 566 minus 66 D. B. Locking type plug and socket Sprayberry Academy of Radio 553 connector and either suspension mounting or Corp. 569 stand hickie furnished at no extra cost. Full Standard Tranformer details. Data Sheet No. 13. Free. Send for it. transformers and insulators. A novel dr- Teleplex Co. 551, 556 BRUSH HEADPHONES arrangement provides automatic elec- Torsion Grip Mfg. Co. 573 cuit Trimm Radio Mfg. Co. 556 Response 60 to 10,000 cycles. No magnets trical switching from long to short waves, Triplett Electrical Instrument Co 551 to cause diaphragm chatter. Specially designed eliminating the usual manual switch. Tri -State College 576 cases minimize breakage. Light in weight. Only Tung -Sol Radio Tubes, Inc. 568 6 oz., complete with headband and cords. A quality product at a low price. Details. Data High- Fidelity Receiver Utah Radio Products Co 561 Sheet No. 10. Free. Send for it. The American -Bosch 1936 line of receiv- Webster Co., The 555 ers, equipped with metal tubes, features a Weston Electrical Instrument Corp 567 which is a new type of Wholesale Radio Service Co. 570 Centromatic unit, Wright DeCoster Co., Inc. 572 assembly and construction to guard against electrical interference and losses. Zephyr Radio Co. 558 MICROPHONES MIKE STANDS TWEETS, HEAD PHONES LOUD SPEAKERS

www.americanradiohistory.com RADIO NEws FOR MARCH, 1936 575 JUST STARTING TO BUILD A NEW "RIG "? RADIO NEWS WE STOCK ALL "BLUEPRINTS" RADIO EQUIPMENT FOR TRANSMITTER COMPLETE sets of construction REQUIREMENTS t "blueprints" including full -scale picture LICENSED RADIO AMATEURS wiring diagrams, chassis The great specifications, drilling layouts, Coyne shops in Chicago have a world- AT BOTH OF OUR STORES etc., wide reputation for training ambitious fellows Our catalog on request only to those are available on the following: for this big-pay field in only 12 weeks. Then help living in Pennsylvania- Ohio -W. Virginia. you by giving you lifetime employment service. "DRAGNET " -A 2 -tube battery op- By my new plan you can take advantage of their erated short -wave receiver providing 1 wonderful method of learning -by-doing NOW. stage untuned r.f. (34 tube) and a dual CMRDI purpose type 19 tube which serves as SEND TODAY FOR DETAILS OF MY 601 -3 GRANT ST., 30 TWELF H ST. a regenerative detector and 1 audio stage. PITTSBURGH, PA. Y WHEELING, W.VA. Described in August, 1934, issue. Price Established 1919 25c. "Pay- Tuition -Af ter - Read Classified Advertising "SKYSCRAPER " -A fully shielded, -It Pays short -wave receiver. Includes GDG tuned Graduation" Plan r.f. stage, 6C13 Advertisements in this section twenty regenerative detector and Train for Radio in 12 weeks on real Radio, Sound cents a word for each insertion. Name a 41 pentode audio stage. It operates and Television equipment. and address must be included at the above from a.c, power supply unit or batteries. Send the coupon today. If rate. Cash should accompany all classified Features single dial band -spread tuning you are short of money I'll with standard plug -in send you all details of my advertisements unless placed by an ac- coils. Described finance plan. If accepted, you credited advertising agency. No advertise- in November and December, 1034, is- won't have to start paying tui- ments for less than 10 words accepted. sues. Price 25c. - tion until five months from Objectionable or misleading advertise- 1 the date you start school, ,' and thenyou'll havel8 months ments not accepted. Advertisements for "SCOUT'S OWN " -A simple, mod- to complete your payments. these columns should reach us not later ern 1 -tube (type 30) regenerative re- Send for Big Free illustrated than 3rd of 2nd month preceding issue. ceiver for short -waves. Described in Book telling all about the September, 1934, COYNE and how many TECK PUBLICATIONS, INC. issue. Price 25c. earn while learning and 461 Eighth Ave. New York, N. Y. "training you can get there "RADIO NEWS TRAP -CIRCUIT without book _,IAA TENATUNER " study or _ /. .PM -An inexpensive, easily useless T/VLTJ. ^' A.C. Auto Generators constructed device for use with standard theory. broadcast-band receivers. It incorporates 5 different circuits; TURN scrap into money. Autopmver shows you how 3 antenna tuning cir- COYNE easily end economically Stun gent, atom can be converted cuits for boosting signal voltage, and 2 ELECTRICAL SCHOOL into A.C. or D.C. general. h amt D.C. motors, 2 to 1000 wave -trap circuits. No tubes, or excit- 500 S. Paulina St., Dept. 36-3K, Chicago, III. volts; for sound, radio, p.m es. light, or welding. No ing voltages are required- Described in previous experience neci,,111 -complete information all July, 1935, issue. I MR. H. C. LEWIS, President In new with simple and. Price 25c. book, instructions illustrations. 1 600 S. Paulina Endorsed by thousands. Only 01.00 postpaid. Autopower, St., Dept.36 -3K, Chicago, Ill. I I Send loc., 414 -A S. Hoyne Ave., Chicago. "2 -VOLT DX'ERS SUPER " 7- me the BIG FREE Illustrated Book on tube -A with details of your 'Pay- Tuition battery operated broadcast receiver, IRADIOGraduation" Plan -After Agents Wanted of special interest to the rural listener and DX fan. It utilizes the latest 2 -volt I NAME tubes, three ...., I AGENTS: Stich -on -AA'indow Sign letter -s. 500% of which are dual purpose profit. Write today. Meta 11ic Letter Co., 422 N. tubes (LAG, 1B5 and 19), thus permit- ! ADDRESS Clark, Chicago. ting 7 tubes to perform the function of 10. The set is equipped with automatic CITY STATE volume control, Code .11ae¡illes tone control and a signal - L_._------IME MIS strength meter. Described in August -- --I OMNIG RAPH Cade Tel gel ahead quickly. Thou- and October, 1935, issues. Price 50c. sands satisfied. There'_ money ìn it. Dials exchanged free. $2.51) to $22.tm . Cam fugue. Easy Terms. Dealers, "RADIO NEWS Agents Inquiry inviini. Onrnigr:gdi Mfg. Co., 810 E. DX HOPPER -UP- :ill St., Brooklyn, N. Y. PER" -This 4 -tube converter complete with its own power supply, can be used with any tuned r.f. or superheterodyne Correspondence Courses broadcast band receiver to provide tremendously increased selectivity and sen- USED Correspondence cc, es, and Educational Books sitivity on broadcast sold on rented. 1nexpaaavo. .honey -hack guarantee. -band reception. De- Write for Free Catalog Iiains 4000 bargains. (Courses scribed w October, 1935, issue. Price Bought. I Leo Mountain, Pi -salt. Alabama. 50c. JUST Frog Raising "TAYLOR -COCKADAY OCEAN HOPPER " -A single -range short -wave OFF THE FROG RAISERS WANTED. Start backward. We have superheterodyne receiver covering the breeder:, instruction :. m:nkcr. Write. American Frog principal European and domestic short- PRESS Canning Company (510 , New Orleans, La. wave broadcast bands from 19 to 49 meters. The circuit uses 9 metal type Help WT-anted tubes which includes 2- 6K7's, 1 -GAS, Completely Revised! 2- 6C5's, 1 -GHG's and 1 -5Z4 rectifier, The MEN: Write far catalog. The New Radolek 1936 Profit Guide is SERVICE 5 tube, Snperhet, set features air -tuned i.f. transformers, a the most complete Radio Parts Cata- World wave, $13.30. l'arte Set. All Wave, Complete dual ratio airplane type log With \vindehargnr. we lee it is eiy will not be undersold. tuning dial and ever published. Completely revised Ct iiCO, Redding, Iona. other latest developments. Described in -right up to the minute, bringing you November, 1935, issues. Price 50c. everything in Radio -at the right Patent Attorneys prices. Packed with valuable money- saving "radio -buying" information . "P.C.A. OBSERVER " 3 -tube selector, -A pre - every page brings you extra profits! If converter and amplifier unit, PATENTS -Advice anti .tl.i. free. Highest refer - covering the Contains over 10,000 individual Re- rnrra. Irrst results. ('I 071 R1m,5 as-cured. Watson E. broadcast and short-wave pair Parts -hundreds of new items Coleman. Patent Lawyer, 724 0th Street, Washington, ranges from 550 to 15,000 ke. in 3 hands. a complete new selection of Receivers- D. C. A 6K7 metal type tube is used in the and Amplifiers. Radolek offers you r.f. stage, followed by a GAS tube func- one complete source for all your Radio PATENTS. lust t sleti 11 "floc to Establish Your tioning as a combined detector and oscil- requirements. . . . Everything you Eights" and farm. "Evidentc of Conception" -sent Freer lator. need The device -always in . Lancaster. .55111111' S i; mcl, 414 Bowen Building, has its own power sup- tock ready for Washington, O. C. ply, using an S4 for rectification. De- prompt delivery to you. This Book is scribed in December, 1935, and present your handy index to Radolek's huge issue. Price 25c. storehouse of Radio materials . Printing you need it-it's FREE. Send for it! 2000 BUSINESS cards neatly printed $1.50. Free sam- RADOLEK restricts distribution ples. Atlas Distributing Co., 1,14 Bedford Ave., Pitts - of burgh, l'a. the PROFIT GUIDE to those actively and commercially engaged in the Radio Business. Please enclose your Busi- Patents and Inventions ness Card or Letterhead. INVENTIONS COMMERCIALIZED. Patented er un- The Technical Review patented. Write Atlagn Fisher Company, 278 Enright, St. Louis, Missouri. (Continued from page 559) Radio J2 -Radio Parts Catalog, of Insuline Corpora- RADOLEK tion of America. Free. JI 572 W. Randolph Street ARMY -NAVY give:, fr't Radio Operators' training for -Book Circulars of Alfred A. Ghirardi. Chicago, Illinois service on Strips, Airci1k. Sa tary, expenses paid. In- Free. formation pamphlet, linty ta apply, 20e. Continental, J4- Latest Wholesale Radio Service Co. \aine Box 344 V, Indianapolis, Ind. Catalog-listing receivers, sound equipment, amateur and service replacement parts, etc. Wind Driven Lights Free. Addrese Fl- Catalog of Radio Parts. The National Serviceman I ELECTRIC LIGHTS -WIND DRIVEN -You build Co., Inc. Free. Dealer I O Expert I them. Write, Wind \letae Electric, Ridgway, Montana. (Turn to next page)

~~www.americanradiohistory.com 576 RADIO NEWS FOR MARCH, 1936~~

e for DEPENDABILITY Radio Amateur's Handbook AMATEURS, short -wave enthusiasts, experi- mentors and others, will be interested to know that copies of the A.R.R.I. Handbook which is reviewed above can be obtained by forwarding check or money order for $1.00 to: RADIO NEWS, CURRENT AND VOLTAGE 461 Eighth Ave., New York City.

Amperite replacements. tor AC- riite radio DC sets now LIST $1.25. Amperite amateur's 3.40 can replace AC -DC set regu- lators 50x3, 300, and SB. Also new handbook low price on replacements for as dependable as the light- 2 -Volt Battery Sets, List $1.60 house that guides in the Write for CHART CV. night- /AMPERITECO. 561 BROADWAY NEW YORK AMERTRAN

TRANSFORMERS Thordarson Transmitter Guide Amateurs and Engineers THE Thordarson Transmitter Guide is a 32- page book containing complete technical data INSULATED alike prefer AmerTran on more than a dozen different transmitter units Metallized RESISTORS ranging in power from 6 to 1000 watts. Both Develop- Transformer Products, be- the beginner and the advanced amateur will find The Outstanding Resistance it interesting and instructive reading. Circuit ment in the History of Radio cause they know from ex- Sample I.S watt Insulated Resistor FREE constants, coil data and parts lists are included. to benaßde servicemen and aviateurs.' perience that these prod- Because of the size of this booklet and the work CO. free, INTERNATIONAL RESISTANCE ucts are dependable; that involved in its preparation, it is not offered 401 N. Broad St. Philadelphia, Pa. but costs 15 cents. It is well worth several times In Canada, 187 Duchess St., Toronto they are designed and con- this slight amount. Copies may be ordered from RADIO NEWS, 461 Eighth Avenue, New York, structed according to the N. Y. highest standards of qual- CODE TEACHER ity and to meet the most It's easy to learn the code with the lnstructouraph. Book of Instructions exacting requirements in shows you how to study to best advantage. For Rent -on attractive terms. Audio Amplifier and Radio Rental paid may be applied toward Service Bench purchase price if desired. For Sale - Transmitter circuits. The cash or terms. Just send post -card to- (Continued from page 553) INSTRUCTOGRAPH COMPANY, Dept. NR -3 Ask for Bulletin No. 1002 912 Lakeside Place Chicago. Ill. must be taken from the bulb side of Reyreaentaliva for Canada Toronto which College of Caneda.Ltd.. 863 Bay St. AMERICAN TRANSFORMER the lead in which the switch is connected- Radio COMPANY which, incidentally, explains why the switch is there, rather than utilizing the 177 EMMET ST. NEWARK, N. J. simple expedient of plugging the line in or INVENTORS out. This lead, ending in a test prod, is TIME COUNTS used for ground tests. By opening the in applying for patents. Don't risk delay in protecting year ideas. Send sketch or model for i nstructions or te for FREE BOOK having first tested for juice Patent Guide for the Inventor" and "Record of Once gtien switch, after form. Na charge on how to proceed. Prompt. careful, efficient COLLEGE in the receptacle the bulb will light when- Degree in 2 Years CLARENCE A. O'BRIEN AND HYMAN BERMAN ever the prod hits ground. (It may, of 309 -Z Adams Building' Washington, D. C. Registered Patent Attorneys before U. S. Patent O$ae Complete Radio En- course, be necessary to reverse the plug.) gineering course in 96 The test prod is mounted in the handle of weeks. Bachelor of a five -and-ten fountain pen. When the Science Degree. Radio is screwed ttelevision, talking pic- prod is not being used, the cap RADIO COURSES tures and the vast on, thus keeping it from getting someone RADIO OPERATING: Prepare for License Exam. RADIO SERVICING: electronic field) offers unusual opportunities AMATEUR CODE radio engineers. Courses also in Civil, Including Short Wave trained ORDINARY LAMP CORD New Course in ELECTRONICS: Electrical, Mechanical, Chemical, Aeronautical, 'TROUBLE Upon Request Administra- SWITCH s). LAMP Day and Evening Classes- Booklet Architectural Engineering; Business SCHOOLS tion and Accounting. Low tuition, low living costs. .1 _ NEW YORK Y.M.C.A. for technical two -year courses. Those 7 W. 63rd Street, New York City World famous pLuS who lack high school may make up work. Students CAP TEST PROD from all parts of the world. Located in picturesque ® 1 J hill and lake region of northern Indiana. Enter January, March, June, September. Write for catalog TEST PROD ON SAME LEAD AS SWITCH 1636 COLLEGE AVE. ANGOLA, IND. FI G.5 lienflad into trouble in case it should fall afoul of Radio Tubes Ram the chassis when the light is merely being For quiet, noise - used for illumination. THE KEN -RAD CORP., Inc., Owensboro, Ky. free reception "I find the ground test most useful. It AN TE.NA'A (both shortwave ALL -WAVE and broadcast) will show up a poor ground or an open have a "NOISE - It will identify antenna and ground if they MASTER" in- have been reversed or disconnected from stalled by a quali- tracing might be difficult, It fied service man. the set, when Now l0¢ Stick to antenna will also show up a grounded antenna."- products designed Earl Kane, Livingstonville, N. Y. Think of it! For the small price of by specialists! Com- 10c you can now get the old favorite, plete literature And Com- on request. SERVICE NOTES WILD WEST STORIES plete Novel Magazine -the publica- List Price Here's a chance for servicemen to obtain tion that features new thrilling ad- CORNISH WIRE CO., Inc. $6.75 a Wright -DeCoster Multi -test speaker ventures of Flash Steele in every 30 Church Street. New York City (matches all tubes, all output transformers, issue. The quick- trigger action of all field combinations, voice coils, etc., and this cowboy has gained tremendous TWINS comes in an attractive carrying case) at popularity among western fans every- NOISE -REDUCING half the trade cost. The speaker can be where. In addition, there are numer-

LYNCH HI -Fl LYNCH obtained from your dealer - at the usual ous exciting short stories. Get your ASSEMBLED ALL. If your dealer copy of the April issue today sale cannot supply FILTERADIO discount. From one to ten coupons are -on WAVE ANTENNA at all newsstands! All ready to hang. you, order di- Cuts out objectionable packed with various Wright -DeCoster e 90% of installa- write the light tion time. p6.75 rect, or line.fromto in- products, 75 of which can be redeemed by Amazing re- for folder. stall; simple to S 5UD suits. Lie adjust. List the serviceman for half the cost of the Wild West Stories Novel Magazine Arthur H. Lynch, Inc., 227 Fulton St., N. Y. Multitest speaker in merchandise. This And Complete PIONEER OF NOISE- REDUCING AERIALS offer expires January 1st, 1937.

~~www.americanradiohistory.com 10,00( Radio Me~~

CONTENTS Can't, ReWronj of four months, the entire first edition of the 1936 Chapter I In the short period RADIO DATA BOOK has been distributed. Ten thousand radio TELEVISION men received copies of this valuable reference guide -and many enthusiastic letters have been received by the editors. Radio men every- 2 Chapter where found its contents supplied just the material they needed ! A METAL TUBES second edition is now available -but our supply will not last long with

the present demand ! Therefore, we urge you to send for your copy Chapter 3 today -while our supply lasts! SHORT WAVE RADIO Every Radio Man Needs This Book is crammed full hard -to Chapter 4 The 1936 RADIO DATA BOOK of -get information. It is a large 8" by 11" book with over 120 illustrations AMATEUR RADIO - bound in a durable green cover that will last for years. Here are a few of the dozens of articles : Disk vs. Cathode Ray Television Sys- Chapter 5 tens- Description and Characteristics of Metal Tubes -Short -Wave BROADCAST RECEIVERS Reception Aids-Short -Wave Circuit Design -Constructional Details on Five Short -Wave Receivers -Amateur Transmitters, Receivers and Chapter 6 Transceivers -Characteristics of Transmitting Tubes -Broadcast Re- ceivers- Short -Wave Converter- Trap -Circuit Tenatuner- Broadcast- SERVICING AND SOUND Band DX Converter -Using Cathode -Ray Oscillographs -P. A. Sys- EQUIPMENT tems -Sound -Head Servicing- Service Sales Tips -Calculating Voltage Divider Constants -Formulas -Hints and Kinks -Wire Table- Trans- Chapter 7 former Design Table -Short -Wave Station Lists-and plenty of other ENGINEERING DESIGN worth -while information! Get Your Copy -FREE! Chapter 8 RADIO NEWS. Dept. 363 RADIO EXPERIMENTING The 1936 RADIO DATA BOOK 461 Eighth Avenue, New York, N. Y. is not for sale--at any price ! It was Enclosed find $1 (Canada and Foreign $1.25) - published solely as a gift to those for five issues of RADIO NEWS and send me, without cost, a copy of the 1936 RADIO Chapter 9 placing new or renewal subscriptions DATA BOOK. STATION LISTS for RADIO NEWS. YOU can get a copy- absolutely free-by sending us Name your subscription for the next five issues of RADIO NEws -at the money- Address Mail The saving price of $1 (Canada and For- eign $1.25). Present subscribers may City State Coupon Now have their subscriptions extended.

~~www.americanradiohistory.com Q AL Th-Y NS DE AS WELL AS UlSI D E..:Iigfa deJerizegidit r with Sk 2A/tfte Ta/arh 4/2 to 2,400 METERS :~~

*METAL OR CLASS 6 WAVE BANDS SAVE Features 80 Advanced TO 18 Tubes and 6 wave bands are but S0/0 `(d=t COMPLETE two of the 80 advanced features its leadership ad- ONCE again, Midwest demonstrates adult /87a6e4 that include every worthwhile by offering the world's most powerful super de- vantage, that even the most critical is a master achievement could luxe 6- tuning range radio. It Got/GIANT radio technician and enthusiast ...today's most highly perfected, precisely built, ask for. Some of the other exclusive instru- THEATRESONIC Button, laboratory tested unit. It is a radio -musical features are: Station Finder ment that will thrill you with its marvelous super enabling "hams" to secure CW- acousti- tone...crystal -clear SPEAKER"- silences the Silencer Button, which performance...gloriousnew`concert" realism...andmagnificent foreign reception. set between stations-38 Tuned Circuits give Maximum Selectivity - Only Midwest Gives 6 Tuning Ranges (41/2 to 2400 Meters) 4 Gang Condensors -Reinforced Capacitors radio in the world that posi- W .RS! and Pre -aged Intermediate Frequency Trans- Midwest is the only TER51 formers prevent drift, etc. Thebalanceof the 80 tively covers every possible and useful wave band. features are described in detail on pages 12 to Accurately made, recisely assembled, rigidly tested, The Midwest "A" band chart, illustrated at lef , 21 inclusive, of the new FREE 40 -page catalog. Luxe radio assures the brilliant shows how the perfect reception of the Midwest this 18 -tube Super the widely varying powers assigned to Before you buy any radio, write for the free radio "hams" and enthusiasts equalizes and and learn about the super performance that those fortunate stations enjoying cleared channel 40 -page 1936 catalog, demand. The 18 tubes permit of advanced circuits making These stations successful Midwest Laboratory - To - You semi -cleared channel broadcasting. it possible to use the tremendous reserve power, and to come in clearly and with equal volume. The short policy that saves you 30% to 50%, that gives maximum output of the powerful new are operat- days free trial in your own home. exert the sustained wavering lines indicate that many stations you 30 tubes. These sets are vibration tested, any times, until the same wave length. These stations are useful No middlemen's profits to pay. You buy means of adjustment are locked ing on set. direct from Laboratories "creeping screws" and other only when one of them is located close to your at wholesale price, permanently in position. It is interesting to note that this Charts, illustrating the stations that can be making your radio dollar go twice as home bands, are pictured far. You can order your 1936 Midwest is the only secured on the five additional is at t It id is catalog. radio from the new 40 -page catalog with as receiver that tt NYrf'i on pages 20 and 21 of the Midwest All shrinkage %. ;, ,:"i f much certainty of satisfaction as if you were "aged." \4k t ¡1 You save 30% to 50%... you get 30 days FREE trial. and driftare completely a Midwest radio in to oome yourself to our great laboratories. by the use ..as little as $5.00 down puts eliminated your home. You are triply protected with a One -Year of such features as Guarantee, Foreign Reception reinforced capaci- Guarantee and Money - Back tors, pre -aged inter- Guarantee. Write for FREE mediate frequency for yourself that transformers, as well 1936 catalog. See "A" BAND i. this super radio will out -perform sets as elaborate pre-aging - times as much. tests and processes. CHART costing two and three TRIAL OFFER g= MAIL COUPON TODAY for FREE 30 IDAY and 40 -PAGE FOUR COLOR CATALOG

MIDWEST RADIO CORPORATION, User -Agents -R, Cincinnati, Ohio. Make Easy Dept.11 Extra Money my part, send Without obligation on Address me your new FREE catalog, complete your liberal 30-day FREE CheekHerefor details of Town __._.-- .State _.._ trial offer, and FREE Miniature Rotat- details if interested in a Midwest All-Wave Battery Radio ing 18-tube Dial.This is NOT an order. Check

~~www.americanradiohistory.com~~