April, 1924 25 Cents
Total Page:16
File Type:pdf, Size:1020Kb
APRIL, 1924 25 CENTS (Reg. U. S. Pat. Off.) WHANDREWS "HIS FORMER PLAYMATE" www.americanradiohistory.com CUN iNGHAM CUNNINGHAM DcT{CTQp-AMPLIFIER OF IECTOR-AMPUFIER MQ:DELGII MODEL CI2 PAdENrEo PATENTED iiNGHAM R-AMPLIFIEP LiC 299 ' C- 11 -1.1 Volt ENTED .25 amp. Dry C -2119 -3 Volts. C-12- Similar Battery Det. and 06 amp. Dry to C -11 with Amp. Special Battery Det. standard base Base and Amp. $5.00 $5.00 $5.00 &complete line of--- C -300 -6 Volts Gas Content Detector $5.00 RADIO TUBES FOR EVERY TYPE OF RECEIVING SET WHATEVER type of receiving set or circuit you C -I2 is identical to C -x x in operating characteristics, are using -one or more of these five Cunning- but is mounted on a standard base to permit the use ham receiving. tubes will be ideal for obtaining of a dry battery tube in sets equipped with standard maximum distance reception with perfect reproduction sockets without the aid of special adaptors. of both voice and music. Whenever storage battery supply is available for fila- Three of the five tubes are designed to use dry batteries ment lighting, the C -3oo will be the best tube to use as for filament lighting. C -29g, the latest development in a detector because it is the most sensitive for the Radio Tubes, is compact in design and highly efficient reception of distant and weak signals. in operation as a radio frequency amplifier, a detector Under the same condition, C -3orA will be the best and as an audio -frequency amplifier. When used for tube for amplification at either radio or audio fre- the latter purpose, the output of two stages is sufficient quency, because it gives greater gain per stage than for the operation of a small loud speaker. any other tube on the amateur market. The new patented filament used, similar to that in C -299 draws The most remarkable feature of this tube is the new only .25 amperes at 6 volts, reducing the necessity of patented filament used which draws only .o6 amperes frequent storage battery charging. at 3 volts. Cunningham tubes are cov- C-11 is a dry battery tube with a special base for use Patent Notices ered by patents dated 2 -18-08 NNIN in sets having special sockets. It is a good detector and and others issued and pending. Licensed for amateur. PLIFIER audio -frequency amplifier. The filament is lighted experimental and entertainment use in radio communi- C- 301A-6 Volts from a single dry battery and draws .25 amperes. cation. Any other use will be an infringement. amp. Amplifier 3 PE C $5.00 PATENT£ The care and operation of each model of Receiving Tube is fully explained in our new 4o -page "Radio Tube Data Book. ' Copies may be obtained by sending ten cents to our San Francisco office. Q Home Office: 182 Second St. 154 West Lake Street 30 Church Street San Francisco, Calif. Chicago, Illinois New York City, N. Y. www.americanradiohistory.com RADIO for APRIL, 1924 1 ghe l`oyalty cRa Gt1,0 KENNEDY MODEL V Like the Artist Standing 1081 efore You So pure, sweet and life-like is the tone of the new Kennedy Radio out whining, whistling noises that interfere with listeners living Receiver, Model V, that it really makes you feel the artist's presence near you. fireside -performing for you, in your own home! -standing at your When you buy your Kennedy Model V, you will add an attrac- And, with this new Kennedy, it is astonishingly simple to bring tive piece of furniture to your home. The mahogany cabinet is to your own living room the best broadcast entertainment in the hand -rubbed to a beautiful finish. The polished black Formica country. You, your wife, mother, son or daughter- anyone -can panel, in contrast with the mahogany cabinet, creates a pleasing operate Model V with an ease that brings its own form of fasci- effect. There is no confusing mass of wires dangling from the nating pleasure. Only one dial is used to "tune in "a station -a cabinet and all batteries are completely enclosed. slight regulation of a second dial controls the volume so you can bring in music or voice soft or pronounced as you wish. Model V is really the receiver for youl It is a permanent invest- ment that will bring you years of pleasure. It is sold, completely Best of all, when once you have determined the dial setting for any equipped with all dry battery tubes, dry batteries and Kennedy station, that station (if it is broadcasting) will "come in" at its own 3000 -ohm phones with plug, for only $125.00 ($127.50 west of dial setting -any night, anywhere, regardless of the kind of Rockies). Other models range from $285.00 to $825.00 (slightly antenna used. higher west of Rockies) completely equipped, including built -in Think of the possibilities herel Many Kennedy owners make up loud speaker. their own station record -showing the dial set- Try this new Model V in your own home -your ting for each station. How wonderfully simple - dealer will gladly arrange this for you. If you can- merely select the station you wish to hear and set not locate him, write us direct for fully-illustrat- the tuning dial to the number of that station. $125 ed literature covering'this and other popular Kennedy models. Another feature about this new Kennedy is one fully equipped that your neighbors will appreciate. It does not ($127.50 west of Rockies) All Kennedy Radio Receivers are regenerative. radiate to any appreciable extent -it does not throw Licensed under Armstrong U. S. Patent No. 1,113, 149. THE COLIN B. KENNEDY COMPANY SAINT LOUIS KENNEDY,.. _ A . ghe cl`Z.oyalty g'cAadi.o Tell them that you saw it in RADIO www.americanradiohistory.com 2 RADIO for APRIL, 1924 Forecast of Contributions for May Issue Prof. C. M. Jansky of the University of Established 1917 as Pacific Radio News Minnesota will start an authoritative series of articles which will give the non -technical man an idea of what is going on in the various volume PI for April, 1921 Number 4 radio circuits in which he is interested. He first takes up an elementary discussion of electric current, charge, pressure, resistance, inductance and capacity. As Prof. Jansky is a member of the CONTENTS for APRIL, 1924 Washington Radio Conference and a well known authority on radio, his articles should be of great interest and value. Radiotorial Comment 9 The Radio Network of the U. S. Navy, By S. R. WINTERS 10 The "Flivver" Super Heterodyne, By E. M. SARGENT 13 Paul Oard presents a number of radio con- struction pointers, including complete Double Rectification with Two -Crystal Receiver, By JACQUE AVON 15 directions for the construction and finish of a radio cabinet. A Burglar -Proof Counterpoise, By ALEXANDER MAXWELL 16 A Single Tube Reflex Receiver, By PAUL OARD 17 A Real Short Wave Receiver, By JOHN F. RIDER 19 Samuel C. Miller has an unusually clear un- derstanding of circuit requirements for maximum The Enchanted Jackass, By EARL ENNIS 21 amplification. These he explains in the course Soldering, By D. B. McGowN 22 of an article on matching impedances. "Super -Autodyne" Reception, By P. J. TOWNSEND 23 Up -To -Date Radio Dictionary, By L. H. LA MONTAGNE 24 D. B. McGown details the construction and A Study of The Frequency Trap, By JEROME SNYDER 25 uses of various types of telephone receivers. A Reflex Receiver for Beginners, By CHARLES F. FILSTEAD 27 A Handy Drill List for Machine Screw Taps 28 By CHAS. F. FILSTEAD Keith La Bar gives directions for making a receiving set The Super- Regenerative Circuit, By L. R. FELDER 29 that will readily utilize any one of a half dozen circuits at will. What You Should Know About Storage Batteries 30 By EDWARD T. JONES Radio Construction Pointers, By PAUL OARD 31 Charles F. Filstead completes his series of Miles of Standard Cable 33 three articles on "A Reflex Receiver for Be- ginners" with a description Official Registration, By DR. A. E. BANKS 34 of the single -tube re- flex unit. Queries and Replies, By GERALD M. BEST 35 4.14 News of The Broadcasters 39 L. R. Felder has an excellent article on the With The Amateur Operators 40 theory of the neutrodyne. With a better under- Calls Heard 41 standing of its principles there is less difficulty From The Radio Manufacturers 42 in assembling this popular circuit. Geo. C. Jones has a suggestive article on effi- cient radio -frequency amplification. RADIO is Published Monthly by the Pacific Radio Publishing Co., Inc., Pacific Building, San Francisco, Calif. ARTHUR H. HALLORAN Editor A. L. Munzig writes helpfully regarding the LAWRENCE MOTT Associate Editor construction of a receiver using tuned radio - GERALD M. BEST Technical Adviser frequency with neutralized capacity coupling. H. W. DICKOW Advertising Manager Branch Offices: 17 West 42nd St., New York City, Telephone Longacre 8248; 157 E. Ontario St., Chicago; 52 Irving St., Boston, Telephone Copley 5107 ; 1102 Republic Bldg., Kansas City, Mo. F. W. Morse, Jr., tells how to make a remark- European Representatives: Compagnie Universelle De Representation ably simple and effective set capable of per- wt de Commerce. Rue des Fortifications, 69, Anvers, Belgium. forming nearly all of the functions to which a Advertising Forms Close on the First of the Month Preceding Date of Issue. vacuum tube may be applied. Issued Monthly, 25c a copy. Subscription price $2.50 per year in the U.