Radio Digest (Oct 1923-July 1924)

RECENT Da.* SHOW GROWTH OF RADIO DIPLOMATS SEE INCREASE IN IMPORTANCE Parts Offer Serves as Indicator of the Universal Use of Ether Waves SPECIAL REWARD OFFER | Coupon Number 20 jj This Special Reward Coupon |g appears each issue in Radio s Digest until further notice. HI When sent in, accompanied = by necessary remittance, ac m cording to the rules govern li iner same, apparatus can be ^ secured. See apparatus list = and rules of offer below. = Save Me — I Am Valuable ( ::Si[R!lii!!!llllI!llllIliIlllllll!llII^ Radio is everywhere, like the medium it uses. Even a cursory survey of civilization, even a glance at its many activities, shows that in every phase of life Radio is present. Reports from every country on earth, even from the jungles and the deserts, emphasize the advance of Radiophony. The more complex the form of civilization the more indispensable has Radio become. Governmental investigations in all parts of the globe reveal that Radio is an integral factor of statesmanship, that without it states and industry would soon languish. These are the recent conclusions of trained observers. Their ideas and suggestions form the bases, in many instances, of extremely important diplomatic negotiations. Nowhere is the growth of Radio more apparent than in the demand for the various parts offered by Radio Digest. It ;cause of the constant expansion of distribution of these parts that aton is called again to the instructions anted below. Caution: In ordering parts, be sure to use the latest list published in Radio Digest. Frequent changes made by the manufacturers make it necessary to have the latest published list supersede all previous ones. Bales to Remember One point must be emphasized to those contemplating taking advantage of the special offer; that is, that the coupons turned In for any Item must, be numbered consecutively, as for example, 1, 2, 3, and 4 or 3, 4, 5 and 6. The number of coupons necessary and the cash remittance, of course, depend on the item sought by the reader. There is no limit to the number of series turned In by any one reader. Another point to remember is that cash, checks and money orders but no postage stamps will be accepted. To make selection moTe simple the items have been divided into eight classes, each class depending on the number of consecutive coupons and amount of cash remittance necessary. Xhe eight classes of items follow: Class A Articles For two consecutively numbored coupons and thirty cents ($0.30) any one of the following articles will be sent: 1 Carter Imp Jack and Plug; 1 Carter 15-Ohni Resistance Unit; 1 Schindler .00025 mfd. Eullt-up Mica Condenser: 1 Schindler .0005 mfd. Built-up Mica Condenser; 1 Schindler .001 mfd. Built-up Mica Condenser; 1 Schindler .002 mfd. Built-up Mica Condeneer; 1 Schindler .0025 mfd. Built-up Mica Condenser; 1 Martin-Copeland Sta Put Plug; Walnart Standard Tube Socket; Walnart t'V-199 Socket; Dubilier Micadons Type 601 (.0001. .00025, .0005, .001, .002. .0025, .003 or .004 mfd.); Premier Grid Condenser (.00025 or .0005 mfd.); Premier Variable Resistance; 1 Carter 25ohm Resistance Unit; Standard Socket Adapter for Delta Midget Tube; Electrad Grid Leak (1 or 2 megohms. with clips I; Amsco 3-inch Dial; Amsco Inductance Switch; Freshman Mlcon Condensers, (.00005, .00025, .00035, .0005, .001. .0015. .002, .0025, or .003 mfd.); Teleradio V. T. Socket; B Metal Mounted Crystal; Aerovox Lightning Switch; Aerovox Serie3 Parallel Switch; Aerovox Contact I^ver; Na-Ald Small Space Sbcket; SeAr-De Vernier Adjuster; 3" Radion Dial, black; 2M," Radion Dial, black; 3"xl" Radion knob with shafts, &" or M", black. 3" Radion Dial, ribbed surface. Class B Articles For four consecutively numbered coupons and sixty "eiits (tO.60) any one of the following articles will be sent: 1 Carter .04 mfd. Special Fixed C»n<lenscr; 1 Carter Jack Switch; 1 Carter Hold-Tttc Jack, One Spring Open Circuit; 1 Carter Hold-Tite Jack, Two Spring Closed Circuit: 1 Carter Hold-Tite Jack. Three Spring Filament Control; 1 Carter Hold-Tite Jack. Four Spring Closed Circuit; 1 Carter Hold-Tite Jack, '■' re Spring Filam-nt Control; 1 Federal Universal jne Plug; 1 Federal Open Circuit Jack; 1 Federal •sed Circuit Jack: 1 Federal Double Circuit Jack: •in-Copeland Shur Grip Plug; 1 Martin-Copeland •*Q> "slar.. Socket; 1 Martin-Copeland WD-11 Adapter; \vt>-ll -Copeland UV-199 Socket; 1 Martin-Copeland , Mtrti" 'apter 1 Martin-Copeland Pull Switch; 1 riV-199 iSia nd 5-polnt Inductance Switch; 1 Carter Varun-C°Pelp1.'ug; 1 Martin-Copeland SPST Knife •^^jAVaS, Siart <n-Copeland SPDT Knife Switch: 1 ciltcb; „l „T»nd L~>PST Knife Switch; 1 Martin-CopeMi, rti»'9?ST W»''» Snitch: Walnart Variable Grid Vand !>P, ii«rt Wductance Switch; Dubilier Mlcadons v?afc-, ^ inoOl. 00025. .0005. .001, .002. .0025. .003. voe 60» *£ mfd); Dubilier Micadons Type 610 (.001, *\ or«« 003. .004, or .005 mfd.); Dubilier Mill -M^.' '■>! I-006 ™fd-> '• Dubilier By-Pass Condenser .rion 'rsP^ .5 mfd.): Premier Untversal Tube Socket; \, .25. .Sdlo Dial (ft. 'A. or ft in. black or white etol^emier Universal Radio Jack, Open Circuit; niversal Radio Jack. Two-Circuit Three Spring; •mier Universal Radio Jack. Two-Circuit Four Spring; piemicr Universal Radio Jack, Filament Control Three Spring, Premier Sw'tch Lever and 10 Points; Amsco 0-Obni Rheostat; Freshman Fix-O. Grid Leak and Condenser; Freshman Variable Resistance Leak (with or without condenser) ; Freshman Mlcon Condensers (006 or .005 mfd.); Teleradio 6Ohm Rheostat; radio 30-Ohm Rheostat; Tehradio\ Lightning ArB-Metal Crystal Tube Detector Type A: H-Metal Me Detector Type D; Aerovox Rheostat; So-Aricuura Tube Socket; 3%" Radion Dial, black: 4" i Dial, black; 4" Radion Dlai, l\lack, ribbed Class C Articles For six consecutively numbered coupons and ninety anj one of the following articles will bo . -Ohm Vernier Control Rheostat: 1 .1 Panel Mo l Federal 6-Obm Rheo ' Federal S-Olim (Power) Rheostat. 1 Ampcrite Automatic Filament Control (with mounting ; 1 Mar n'olatul Marco Rheostat; 1 Martin-Copeland Series Parallel Switch: 1 Martin-Copeland DPDT Panel Snitch: 1 Martin-Copeland 7-1'oint Inductance Switch; 1 Martin-Copeland 9-Point Inductance Switch: 1 Martln-Copolard 11-Polnt Inductance Snitch: Walnart Variable ("rid Leak with ,00085 mfd. Condenser; Walnart Variable Condenser (3-plate .00006 mfd.): Dubilier Ducoo; Dubilier Mlcadon Tvpe 600 (.006 mfd.); Dubilier Mlcadon Type 610 (.01 or .02 mfd); Dubilier By-Pass Condenser (1 mfd.). Premier Universal Radio Jack Filament Control Five Spring; CUL Va-lnble Grid Leak, without condenser: Premier No. 250 Variable Resistance, panel mounting: Thordarson Vernier Rheostat; Hitter Loop Aerial: Martin Copeland Variable Grid Leak: Amsco Multiple Point Inductance Snitch; Amsco 30-Ohm Rheostat; Amsco 50-Ohm Rheostat: Freshman Antenella; Freshman Mlcon Condenser, .01 mfd.; Teleradio Variable Condensers, (3-plate or 11-plate) ; Sot "Read "EM" Binding Posts (S) ; B-Metal Crystal rube Detector Type B: Illinois Cushion Resil'ent Socket: Aerovox Antenna Plug: Aerovox Potentiometer; Aerovox Crystal Detector; S--Ar-De Adjustable Vernier Condenser; Radion Panel ft"x7"x9", black or mahogaiiite; Radion Panel A"x7"xl2", black. Class B Articles For eight consecutive coupons and one dollar and twenty cents ($1.20) any one of the following articles will be sent: 1 Carter 20-Ohm Vernier Control Rheostat: 1 Chindler Radio Frequency Transformer: 1 Martln15-Foint. Inductance Switch; 1 Mart-n-Copcland 19-Point Inductance Switch; Walnart Variable Condenser (5-Plate Copeland 13-Point Inductance Switch: 1 Martin-Copeland .0001 mfd. i ; Electrad Variohm, with mica condenser; Dubilier By-Pass Condenser (2 mfd.); CRL Variable Grid Leak with Condenser; Rcs!stome!er (Type A or 2A) ; Thordarson Variable Condenser. .00025 mfd : Amsco 300-Ohm Potentiometer; Freshman Micon Condenser, .015 mfd.; Teleradio Variable Condenser, 23-nlate; Aerovox Crystal Detector and Condenser, mounted; SeAr-De Variable Grid Leak, with condenser mounting; Fil-Ko-Stat; R, S. C. Variable Condenser, 3-plate; B.adion Panel ft"x7"xl2", mahoganite; Radion Panel 3/16"x7"xl8", black; Radion Panel 3/16"x9"xl4", black; Radion Panel 3/16"xl0"xl2", black. Class E Articles For ten consecutively numbered coupons and one dollar and fifty cents ($1.50) any one of the following articles will be sent: 1 Carter 6-Ohm Automatic Control Rheostat; 1 Carter 20 Ohm Automatic Control Rheostat; 1 Demcal 3-Plate Variable Condenser; Walnart Variable Condenser (13-Plate .00025 mfd.); Turney Outline Reinartz Coll; Dubilier Variodcn (.0004 or .0006 mfd.): ResistomHer (Type B) ; Delta Midget Tube and Socket; Thordarson Variable Condenser, .0005 mfd. ; Freshman Mlcon Condenser, .02 mfd. ; B-Metal Crystal Tube Detector Type C; Aerovox 3 -Gang Socket: Aerovox Double Slide Tuning Coil; Na-Ald 3-Plate Vernier Condenser, with dial: Radion Panel ft"x7"xl8" mahoganite; Radion Panel ft"x7"x21", black; 1 Federal Potentiometer. 1850 ohms. Class T Articles For twelve consecutively numbered coupons and one dollar and eighty cents ($1.80). any one of the following articles will be senl : 1 Acme Pot-Bheo (potentiometer and rheostat) ; Walnart Variable Condenser (23-Plate .0005 mfd.: Dubilier By-Pass Condenser (8 mfd.); P-emier Variable Condenser without dial (.00039 mfd.); Thordarson Variable Cond user. .001 mfd.; Amsco Comrensat'ng Grid Condenser: Freshman Micon Condenser, 0 25 mfd • Teleradio A'ariable Condenser, 43-plate: SeA-De 3-Plate Condenser: Radion Panel ft"l7"x21", mahoganite; Radion Panei ft"x7"x24", black: Radion Panel Vi "xl0"xl2", black; Hadlnn Panel ,V'x9"xl4", mahoganite; Radion Panel ft"xl0"xl2". mahoganite. Class d Articles For fourteen cot seeutlvely numbered coupons and two dollars and forty cents ($2.40) any one of the following articles will be sent: 1 Federal 7-Plate Variable Condenser: 1 Federal 11-Plate Variable Condenser; 1 Federal 21-Plate Variable Condenser: 1 Federal Anticapacity Switch: 1 Demcal Variable Condenser 11-Plate Walnart Variable Condenser (43-Plate .001 mfd.); Duhil'er Variation (.001 mfd.); Dubilier By-Pass Condenser (4 mfd.); Premier Variable Condenser with dial (.00078 m'd ); Premier Hegehog A. F. Transformer, 4 to 1 Ratio; Thordason A. F Transfo-mer. 35 to 1 Ratio; Thordason Variable Condenser, with vernier, knob and d'al (.0005 mfd.) : Tho'dason Variable Condenser, with vernier, knob and dial (.00025 mfd.) ; Rltter Grand C-ystal Set, Amsco Double H. C. Coil Mounting: Na-Ald 13-Plato Precision Condenser, with dial (.000297 mfd.) ; Na-Ald 23-Pln-e Precision Condenser, with dial (.01X1523 raid.). Se-Ar-De' 9-Plate Condenser: Se-Ar-De 17-Plat? Condenser; R, S. C. Variable Condenser, 23-plate; Kedion Panel ft"x7"x24", mahoganite; Radion Panei %"xl0"xl2", mahoganite; Radion Panel ft"xl2"x21", black; Radion Panel ft"xl4"xl8", black. Class H Articles For sixteen consecutively numbered coupons and three dollars ($3.00) any one of the following articles will be sent: 1 Federal Audio Frequency Transformer No. 226 W; 1 Demcal 23-Plate Variable Condenser; 1 Acme Audio Frequency Transformer; 1 Acme Radio Frequency Transformer (R-2. R-3, or R-4) ; Walnart Variable Condenser (13-Plate vernier) ; Walnart Variable Condenser (23-Plate vernier) ; Dubilier Duratran (R. F. transformer) ; Premier Micrometer Variocoupler with dial; Premier Variable Condenser with dial (.0015 mfd.) ; Premier Variable Condenser with vernier (.0004 mfd.); Premier H -gohog A. F. Transforms. 10 to 1 Ratio; Premier Hegehog A F. Transformer, Tube Socket Type, 4 to 1 Ratio; Thordarson A. F. Transformer, 6 to 1 Ratio. Thorda-son Variable Condenser, with vernier, knob and dial ( 001 mfd.) : T. B. H. Radio Head Set. 2.000 ohms; Tulip Loud Speaker, 15-inch, white; Teleradio Vernier Condenser 23-plate; Teleradio 2.000-Ohm Head Set; Na-Ald Tuned R. F. Transformer, one stage; Na-Ald 43-Plate Precision Condenser with dial (.001 mfd.); Se-Ar-De I 35-Plate Condenser; R. S. C. Variable Condenser, 43plate; Radion Panel ft"xl2"x21", mahoganite; Radion Panel ft"xl4"xl8", mahoganite. Carnegie School Offers Evening Course in Radio PITTSBURGH, PA.— A new and practical course in Radio for beginners is one of the new features added to the night courses at Carnegie Institute of Technology. Decision to add this course was made as a result of the demand developing from the widespread interest in Radio communication in the Pittsburgh district. The work will be covered in one year of two terms extending from September to May, and the course has been prepared to appeal specially to amateurs, school teachers, salesmen and dealers in Radio apparatus. No previous knowledge of electricity or Radio is required. Instruction is given two nights each week, and will include lectures, demonstrations and laboratory practice. CONTENTS Radio Digest, Illustrated. Volume VII, Number 1, published Chicago, Illinois, October 13^ 1923. Published weekly by Radio Digest Publishing Company, 123 West Madison Street, Chicago. Illinois. Subscription rates, yearly. Five Dollars; Foreign Postage One Dollar additional; single copies. Ten Cents. Entered as second-class matter at the postolnce at Chicago. Illinois, under the Act of March 3. 1879. "All the Live News of Radio" 1 to 9 Ionization Wrong ; Sun Crowds Radio 3 Flewelling Answers to Queries 6 Further Details of the Famous Miloplex, by tfr's Mystery Man • 10 Simple Explanation of Radio for Everybody, Chapter III — Rectification and' Receiver Essentials, by M. W. Thompson 11 Radio Programs 1Z R.D.-100, A Real Selective Long Distance Receiver IS Editorials; Indigest; Condensed by Dielectric 16 First Steps for Beginners in Radio, Chapter XX — Useful Information and Formulas, by Thomas W. Benson 17 Slide Tuner Hook-up in Simplex Diagram 18 How to Make King Miloplex I, by H. J. Marx 19 Questions and Answers 22 Broadcasting Stations, Part I — Station Schedules 23 Radio Illustrated, a Page oi Pictures 24 Looking Ahead A Push-Pull Amplifier, and How to Make It — the subject of a much requested article by H. J. Marx next issue. Mr. Marx will tell all the details of constructing one of these popular and powerful audio amplifiers, even giving instructions for winding the special push-pull, practically distortionless, transformers. Don't miss this! Trouble Shooting Key for Your Radio Set This special arrangement, to be given readers next week, helps the greenest novice to locate and correct the little slips % that always occur just when one tries to show off his set to a party of friends. Rectification and Receiver Essentials a continuation of the discussion of the principles of the vacuum tube will be Marvin W. Thompson's contribution to the already abundant selection of easily understood technical articles scheduled for next issue. The Untuned Aperiodic Primary, Three Honeycomb Coil Set — -promised this week but squeezed out by lack of space will be here for you as R.D.-I0I. Built by a reader and it works great! Next Week's Simplex Picture Diagram is a good dry cell tube hook-up. It's selective and has lots of volume. Designed for the fan who wants not the simplest set, but one with a few more knobs and dials. Oh Yes!!! Don't Miss King Miloplex the Third — Next issue the Mystery Man will tell you a few more changes to make in your Miloplex set so that you can lay your receivers on the table without their rattling off and falling to the floor when a DX station 2,000 miles away bangs its way in. Early returns from many readers indicate that the Miloplex is THE only set to build for the winter months. Line forms to the right, waiting for next issue and more "dope." Newsstands Don't Always Have One Left WHEN YOU WANT Radio Digest YOU WANT IT! BE SURE OF YOUR WEEKLY COPY BY SUBSCRIBING NOW SEND IN THE BLANK TODAY Publisher Radio Digest, 123 West Madison St., Chicage, Illinois. Please find enclosed check M. 0. for Five Dollars (Six. Foreign) for One Year's Subscription to Radio Digest. Illustrated. Name Address City St«t». NEW TYPE Variable Resistance Leak ONLY THE KNOB SHOWS ON THE PANEL This device is especially built for use as a tuning instrument. Its construction is such that it will withstand unusual usage. Fully garanteed. Absolutely no pencil markings. Can be mounted on any panel in a few seconds. It will enable you to get stations you have never heard before. Complete with either .00025 or a« >w» .0005 Freshman Condenser .$1.00 Without Condenser 75 At your dealers, otherwise send purchase price and ycu will be supplied without further charge. fflas-Fresfi \Z&zc6ci Gondt 106 Seventh Avenue man (o. Inc. New York c4broad at Home Where Shall We Go Tonight? To New York, Cuba, Atlanta, San Francisco or perhaps Honolulu ? Far distant stations are continually being brought in clearly and distinctly with a Crosley Model X-J. Unsolicited letters from users, telling of new distance records are received daily. You, too, at a very small cost, can enjoy the many pleasures and conveniences that this new Croslej' Model affords. CROSLEY MODEL X-J $65 A 4tube radio frequency set. incorporating of Tuned Radio Frequency Amplification, Detector and two stages of Audio Frequency Amplification, with jack to plug in on three tubes for head phones; new Crosley multistats; universal rheostats for all makes of tubes; new condenser with molded plates; filament switch and other refinements of detail. This receiver is exceptionally efficient in long range reception. It will bring in stations at afhiost unbelievable distances clearly and distinctly. We unhesitatingly claim the Model X-J is the best radio receiver ever offered, regardless of price. The t'rosley Model X-J. together with the com Crosleir line of reoervws. ranging iu rrioe Etaoa Jl'ij to $150. are for sale by best dealers everywhere. last rrioes on our equipment west o f Rocki higher. In Canada ado Better -Cost Less Radio Products Write for Free C: CROSLEY MANUFACTURING COMPANY J>.. Pres 104*2 Alfred St. Cincinnati, Ohio M