Ctil:>S ()fficial JI f()IU 112~ A\ IL Vol. 4 No. I March 1979
Philo T. Farnsworth • Those Wild Hams of the '20's Protectina Broadcastinas Past • Collector SPotliaht: Jim Enaland Maiestic Radio Restoration • The Flemina Valve C:til!S ()fficial JI f()IU 112~A\ IL Uol. 4 No. 1 March 1979
THE SOCIETY: The California CONTENTS Historical Radio Society is a non- profit corporation char• tered, in 1974, to pror.iote the Those Wild Hams restoration and preservation of early radio and radio broad• of the '20's. . 1 casting. CHRS provides a me• dium for members to exchange Beautifying That Old Radio. 5 information on the history of January Swap Meet . . . . 6 radio, particularly in the west, with emphasis in areas Protecting Broadcasting's Past. 9 such as collecting, cataloging and restoration of equipment, FEATURE: Horn Speakers. .11 literature and programs. Reg• ular swap meets are scheduled Philo T. Farnsworth .20 at least four times a year, in Novelty Nook. . . . .23 the San Jose area. PRES I DENT: No rman Berge Spotlight Collector: SECRETARY: Dave Brodie Jim England . . . 24 LEGAL COUNSEL: Eugene Rippen TREASURER: James Cirner Majestic 20/23 Restoration. . 25 JOURNAL ED ITOR : Allan Bryant PUBL ISHER AND PRINTER : Don Tube Column . 28 Stoll PHOTOGRAPHER: George Durfey Collectors' Ads inside back TUBE EDITOR: Russ Winenow TECHNIC/1.L EDITOR : Floyd Paul CIRCULATION MANAGER: Larry LaDuc, Jr. MUSEUM DIRECTOR AND COORDINA• Graphic material "borrowed" TOR: To Be Announced, 1979 liberally from Radio News (pub• DR. CHARLES 0. HARROLD AWARD lished by Experimenter-Publish• RECIPIENT: Bruce Kelley, ing Company, Hugo Gernsbach , (AWA) (19 78 ) President) and Radio Retailing HONORARY LIFETIME MEMBER: (McGraw-Hill, Inc.). Paul Courtland Smith (1978)
THE OFFICIAL JOURNAL of CHRS is published quarterly a nd furnished free to all members. The first issue (published in CHRS Official Journal is pub• Sept. 1975) is still avail• lished by California Histori• able ($2.00) , other early is• cal Radio Society , Box 114 7, sues are $1 . 00 each. Articles Moun tain View, CA 94040. Ar• for the Journal are solicited ticles and non-commercial ads from all members. Appropriate for the Journal should be sub• subjects include restoration mitted to Allan Bryant, Editor, hints, information on early 38262 Ballard Drive, Fremont, radio broadcasts and personali• CA 94536. Historical data ties, anecdotes about the pio• for copying or dona ti on should neers, etc. Anyone interested also be sen t to the Editor. in assisting in producing the Journal should con tact the Contents © 1979, CHRS, Inc. 0 Editor. Those Wild Hams of the ·2o·s
by Charles C. Hay, W¢LCE (now called capacitor) went for $15. So, most of us were It was a glorious time to forced to build our own equip• live -- back in the 1920's, ment. when radio communication was The usual receiver consis• just beginning to emerge. Only ted of a coil of wire wound a• a very few top scientists knew round an empty oatmeal box; anything about this new medium another coil inside the box -- and most of the things they was rotated by a lead pencil "knew" were incorrect. But pushed through the box and that didn't deter them from b~th coils. This pair of displaying their errors -- coils was connected to a fine what thev thouqht were "facts" wire sharpened to a point. -- in the public press. The point made contact with One of the notable "facts" the surface of a galena crys• that qot around was the state~ tal. The body of the crys• ment that radio communication tal was connected to one lead was impossible below a wave• of a pair of headphones, and length of 200 meters. (for the other lead of the phones those of you familiar with was connected to ground. With only hertz, 200 meters is a long-enough length of wire 1500 kHz.) So, Congress for the antenna, this contri• dreamed up a radio law that vance could receive radio sig• confined all amateur communi• nals from as far away as 1000 cation to the bands below 200 miles. It needed no outside meters -- or above 1500 kHz. power since all the power was The law also specified that furnished by the radio waves all radio stations had to be themselves. licensed. Little problem While vacuum tubes were that, since a license was known in the early 1920's (they granted upon request and with• were used in World War I) , they out the applicant having to weren't available, except to a submit to an examination. very few lucky individuals. Another part of the law Everyone used a tubeless spark stipulated that only in the transmitter, anyway. big cities were licenses to A spark transmitter was easy be granted. Needless to say , to build. It required simple since many experimenters materials, like a spark coil lived a long way from the big from a Model T Ford, a pair of cities, a lot of transmitters sharpened zinc strips (to act were on the air without the as the spark gap), a telegraph benefit of licenses. What• key, and an antenna. By con• ever call letters were used necting the spark coil through were self-assigned. the telegraph key to an auto• We Built Our Own Equipment: mobile battery, and the secon• All-Of the eq\iTpment we early dary of the coil through the hams used was homemade. There spark gap to the antenna, a guy were only two companies in the entire United States that sold radio parts, and their prices Reprinted from Popular were quite steep. For example Electronics Magazine, Copy• $20 would buy a link coupler. right ® 1973. Ziff-Davis while a variable condenser Publishing Co. was in business. When he pres• sed the key, he drew a lovely spark from the gap . The spark could be received clear across town, if the town wasn't too big, that is. Although the receiving sta• tion had a tuner, it wasn't necessary. Those spark trans• mitters were the original all• band transmitters. When they came on the air, any nearby re• ceiver, no matter where tuned, would pick them up . Along Came Tubes : Late in the 1920's;-Yacuum tubes be• came available. About the same time, commercial broad• YOU ARE INVITED casting reared its head. Peo• to join CHRS and enjoy : ple with money could buy broad• 4 quarterly issues of this cast receivers, precipitating Journal the unpopularity of the neigh• 4 quarterly swap meets borhood experimenter, with his Free ads in every issue of all-wave spark transmitter . the Journal Technical advice on your res• Government regulations, toration problems, etc. which instituted "silent hours" for Sunday mornings and until Annual membership -- $9.00 10 o'clock each evening, came Seniors (over 62) -- $6.00 into effect. Not that this For applications contact: did much to the experimenter. Dave Brodie He usually didn't read gov ern• 315 Cotton Street ment publications, so he knew Menlo Park, CA 94025 nothing of the regulations . or call the nearest represen• tative: At the time the new regula• tions came into effect, radio SACRAMENTO communication was administered Jim England by the Department of Commerce, 6875 Escallonia Drive which had other things to do Orangevale, CA 95602 (9 16 ) 725-6625 besides supply money for radio enforcement. With the absence MOD ESTO of enforcement , the young ra• Eddie Enriques dio experimenter wasn't much 1824 Wy lie Drive troubled . But there were neigh• Modesto, CA 95355 borhood relations to consider, (209) 529- 7596 and if interference was over• RODEO done, the neighbor with his Ronald DeLucchi high-priced broadcast set was 1028 Seascape Circle likely to take the matter up Rodeo, CA 94572 with the offender's parents . (4 15) 799- 2270 This usually resulted in the GLENDALE enforcement of "quiet hours" Floyd A. Paul -- if it didn't terminate ex• 1545 Raymond perimentation altogether. Glendale, CA 91201 (213 ) 242- 8961 I was one of the experimen• SAN DIEGO ters in the early days of ama• C. Alan Smith teur radio. The fact that I 6368 Charing Street could hear broadcasts on my San Diego, CA 92117 cry stal-detector tuner intri• (7 14 ) 268-3620 gued my parents to the point where they shelled-out enough money for a v acuum tube, a Crosley book-condenser and a v ariable tuner. With these treasures on hand, I was able
2 to build a new-fangled super• than the inner diameter of the regenerative receiver. copper cylinder, soldered to A by -product of my new re• it a length of wire, and slip• ceiver was the fact that the ped the new assembly into the copper cylinder. When I was superregen was itse~f a trans• mitter. It interfered mightily finished with this step, the with our neighbor's neutrodyne wires from both assemblies pro• receiver. But that was a prob• truded from opposite ends of lem between my parents and the the glass tube. neighbor. Recovering a length of fila• The superregen would pick ment wire from a light bulb, I up commercial broad~asts. It slipped this down the center was also adept at picking up of the coiled wire. After us• amateur transmissions (after ing rubber stoppers to seal my parents had gone to bed, of both ends of the glass tube course). By this time, ama• (with the wires protruding, of teur operators had acquired course), I applied sealing wax vacuum tubes. Some of them to assure an airtight seal. were even communicating via Later, at school, I attached voice ('phone) ! a rubber hose to the 1/ 4" glass tube and used a vacuum pump to My desire for a tube trans• evacuate the air until the rub• mitter could be described as a "consuming passion." But ber tubing went flat. The only while my parents were deeply thing left was to use a blow pipe to seal the 1/4" glass interested in broadcasting, tubing. the idea of an amateur radio transmitter in the same house My first vacuum tube had left them cold. No money was the filament wire exiting forthcoming. from it through the centers of the rubber stoppers. When pow• I had read of a Chicago ham er was applied to the filament, who had built every part of an it heated up as expected -- amateur radio station. He even and so did the stoppers. The built the vacuum tube. So, I vacuum left the tube with a thought, anything he could do, piercing shriek, and a strong I could do. Building the vacu• smell of burning rubber filled um tube, however, was the big the air. problem. Vacuum tubes grew from Mr. Edison's incandescent lamp. They were large and had four-pronged bases. Making the base was beyond my powers. Fortunately, one of the broad• cast set dealers I happened to visit showed me a receiver eo..,.u, Wiit[ Cltlwt!:O made in Canada. It used Myers AltOUNO LIGHT 9ULI tubes. While the American riL•llfNt tubes were descended from a light bulb, the Myers tube was fathered by a cartridge fuse. Now, this was something I My next vacuum tube (see could duplicate. drawing) produced better re• I bought a test tube, and sults. Instead of having the heater wire exit the tube, a from it cut away the lip and pair of copper wires, crimped closed end. To the body of around the heater wire, did this 2-inch-long glass cylin• the exiting, and all the heat der, I ·fused a length of 1/ 4 " was contained within the tube. glass tubing over a hole made This arrangement functioned previously. Then, after rol• quite well. In fact, I had ling a strip of copper into a three QSO's using the tube be• cylinder and soldering to it fore the vacuum got up and a length of heavy wire, I slip• slowly walked away. ped the assembly into the glass tube. Next, I wound a coil of Condensers and Resistors: wire, much smaller in diameter There were other-components
3 we early hams had to make by to insert a couple of copper hand. Some were easy to make, wires through a rubber cap like tubular bypass condensers. into a bottle half-filled Back then, Hershey chocolate with water, and change the bars were wrapped in real sol• resistance by varying the derable tin foil. This foil, depth of the wires in the wa• some waxed paper, copper wire, ter. Excitement was added and a soldering iron and sol• when the water boiled during der were all an experimenter a transmission. needed to make his own conden• The Power Supply: The sers. power supply was more dif f i• To make the condenser, we cult to make. Hams with lots would cut two pieces each of of money had de motor genera• tin foil and waxed paper to 4 tors to supply their power. inches by 1 inch. After light• Most of us, however, had to ly tacking soldering leads to find another means of obtain• the short edges of the foil, ing power. For example, I the waxed paper and foil sheets took a number of copper plates, were interleaved with overhanas about 4 inches square, and oxi• to obviate any possibility of, dized one side of each with a the plates (or leads) from blow torch. I drilled a hole touching each other when the through the center of each condenser was assembled. Then plate, and, after slipping a the whole was tightly rolled rubber tube around a lona bolt into a cylinder. When finished, and insulating the head and the condenser had one lead corn• nut with rubber from an old ing out of the center of the inner tube, put the bolt cylinder and one lead to one through the stack of plates. side. After bending the side When finished, the plates lead to live up with the cen• were bolted together, ozide ter, the foil was crimped a• face to bare copper. This round the leads and soldered. rectifying setup, with a cou• A bit of sealing wax over the ple of my home-made bypass soldered foil and along the condensers and the· coil from exposed seam of the waxed pa• an old telegraph sounder made per properly sealed the con• a 117-volt de plate power denser. A strip of adhesive supply. tape held the whole thiner to- Finally, there came that gether. · magic night when my parents A variable condenser al- were in bed safely asleep. I so had to be hand-made. The crept downstairs and assembled Crosley book-condenser didn't the set with a galena crystal have enough insulation resis• where the tube would be. With tance between its plates. So, the headphones tightly over my 4-inch-square pieces of sheet ears, I moved the variable con• zinc were cut and fitted into denser until I heard another every-other sawed groove in a amateur. Then I quickly tuned pair of pine guides. An end him in on the superregen. piece which had sawed orooves Taking the galena crystal that mated with the empty ones out and inserting the tube, I in the other assembly had fas• fired up my rig and gave him a tened to it the rest of the call. I was lucky. He came zinc plates. When the two back to me, and that was my were meshed, we had a crude first QSO, the high point of variable condenser. my life. The QSL card I re• Resistors were more of a ceived from him still hangs problem. The carbon cores on my shack wall, some five from flashlight batteries decades after it was sent. could be used, but they were rather limited in their resis• tance. Even when a number of them were connected in series, The Editor would like to the resistances obtained were thank Carles Hay for his per• often unsatisfactory. Nor mission to use this article. could the resistance be con• The preceeding article is not trolled. The way to go was for reproduction. 4 Greening of the Grid During the early experiments with the first crude handmade radio tubes , it was t h e custom of Dr . DeForest to giv e d i rec• tions to his assistants some• what in the following manner: "Here . .hook this to that , and that to this. Bring this wire o v er to that post and move this o v er there." In the rapidly shifting tests it was , at times, dif• ficult to differentiate be• tween what was "this , that or the other thing , " so one day , in a state of exaspera• tion, an assistant impulsively ask ed : "Doc , why don ' t you name some of these parts, so we'll know what you're talking about and what we are doing? " "All right," snapped De Forest in reply . "You know what the filament is and which is the 'wing' (now known as ' p late' } , so we ' ll call this other jigger -- the GRID , - • because that ' s what it look s like -- a roaster grid . " Then, quickly adding, as if it were equally important : . and remember this . i n fact ma k e a sign and paste it on the wall: REMEMBER, GREEN TO GRID and Red to Wing . " To this day , that order h as nev er been countermanded, a nd we find that -- in every coun• try in the world where elec• J''"B" tronic circuits are p lanned or Elimin ators used -- the "lead to g rid" is take the pl:ace of "BM Bat· Every inch of Sylfan Reproducers 1s always specified in the color tc:rid,3n d ino.:as.: )O'-'T ran6<' -c!.Jrify :yot 5 The Journal swaP Rights of Reciprocity The CHRS grants Rights of Recipr ocity to other vintage radio organizations. The pur• pose of the agreement is to improve cormnunication between clubs and to promote the ex• change of ideas. A part of this agreement is an exchang• ing of journals, and the right to reproduce each other's ar• ticles. Organizations that have re• ceived Rights of Reciprocity from the CHRS may reproduce our articles, except those labeled -- Not for Reproduc• tion. These are special ar• ticles the Editor has obtained permission to print, and they are not for reproduction. The CHRS requires full dis• closure as to source and author and requests a copy of any journal in which our articles appear. If your organization is interested in establishing rights of reciprocity, please contact the Secretary, Dave Brodie. Please note the following Journal deadlines: June issue -- May 1, 1979 September issue -- August 1, 1979 December issue -• November 1, 1979 The Cats Whisker Response to the offering of the "Cats Whisker" book has been excellent. On March 1, the final order was placed with the publisher . These books will be mailed out to indivi• duals as soon as they arrive. No other mail orders will be accepted. There will be a small supply of hard- and soft• cover editions available at the Foothill Meet -- while they last. - Allan Bryant 6 The CHRS holds several swap meets each year for the bene• meet fit of its members. Members by George Durfey . are encouraged to invite poten• tial new members to attend these meets . However, a com• plaint has been made to CHRS that antique dealers in the area have been invited to swap meets by certain members. We request that antique dealers not be invited to our swap meets . The reason being, at a recent swap meet, one of our members wanted to buy a reason• ably-priced radio, but found it was already sold. He later found this very same set at a local antique shop , priced at five times the price asked at our meet. This type of ac• tion defeats the whole purpose of our swap meets, and only succeeds in driving up the prices of antiq ue radios to an artificially high level. If complaints continue to come in, in regards to this matter, CHRS has the right to refuse admission. Let's keep the meets for members and their guests only -- not for dealers! the Cover Famous RCA Trademark Reju• venated : Here is one version of the famous Dog and Phono• graph trademark, showing how it will be used in TV and print advertising as an ad• junct to the bold contemporary "RCA" letters. Plans also call for the "Nipper " trade• mark to be gradually phased into useage on RCA products, shipping cartons, sales promo• tion literature and company vehicles . The dog and phono• graph symbol is regarded as one of the world's most popu• lar animal trademarks in use today. The trademark has been a standard for more than 70 years. 7 Radio News for Febr11ary, 1923 8 Protectin2 Broadcast in2s Past by John Palcewski Until recently , anyone in• terested in radio or televi• sion programs of the past had to wait for reruns or documen• taries, or get special permis• sion to search through such sources as network archives, of the speeches delivered by university or private collec• Herbert Hoover and Franklin tions . Now, scholars, teach• Roosevelt during the campaign ers, researchers, historians of 1932. An extensive collec• -- and even the merely curi• tion of World War II material ous -- can visit The Museum of is planned by the Museum, be• Broadcasting on New York ' s ginning with the coverage of East 53rd Street , and review a full day of broadcasting at an array of historical audio the start of the war in Sep• and video tapes that cover a tember 1939, and at its con• half- century of American clusion in August 1945 . broadcasting . Access to this wealth of ma • For a suggested contribu• terial is surprisingly quick tion of a dollar per visit, or and easy . A visitor goes an inexpensive yearly member• through a computer-generated ship, anyone can replay such card catalog, much like that television gems as General found in a public library . Douglas MacArthur addressing Listed are more than a thou• a joint session of Congress sand individual radio and te• shortly after his firing by levision programs, indexed not President Truman, or Edward only by title, subject and R. Murrow ' s 1954 interview with date, but also by director , historian/poet Carl Sandburg, producer, writer and technical or Vladimir Horowitz's Carne• and cast credits . A t ypical gie Hall Recital , or even the program in the collection may premiere broadcast of "I Love be listed under as many as 15 Lucy," starring Lucille Ball different headings. and Desi Arnaz. Once a particular program The Museum's collection is is located, a librarian sends not restrict ed to television; the call number to the Museum's also available is a diver se storage area. Within a few range of radio programs f r om minutes, the desired tape is the earliest days of broad• placed into one of eight modern casting . A visitor may tune broadcast consoles , containing in a 1935 broadcast of "Major audio and video playback ma• Bowes and His Original Amateur chines . The tape is loaded in• Hour," 11 Arnos 1 n 1 Andy, 11 11 The to the machine, and the visi• Lone Ranger , " "Ma Perkins," tor views or hears his program and many other popular hits selection. Each of the broad• of that era. In the collec• cast consoles can accommodate tion are speeches by US Presi• three people at one time , and dents beginning with Warren all eight of the consoles G. Harding , and including 38 or any combination -- can be 9 plugged into the same program within three feet of any tape at the same time. The entire storage. rack . operation, with its ultramodern This security consciousness television monitors, keyboard extends, naturally, to safe• buttons, knobs, switches and guarding the tape collection earphones , resembles a scaled• from fire. If room tempera• down version of the control tures exceed 140 degrees, Du room at the Manned Spacecraft Pont's Halon 1301 fire extin• Center in Houston. guishant is immediately dis• Repository Established: charged. Through a special The Museum of Broadcasting is chemical reaction, any fire the brainchild of CBS chairman would be snuffed in seconds. William S. Paley , who decided The extinguishant is clean that "some serious thought" and dry, leaves no residue, should be given to the preser• causes no damage, and re• vation and collection of im• quires no extensive cleanup portant examples of broadcas• following discharge. ting. He feared that a myriad The Museum of Broadcasting of radio and television re• is helping to preserve for pos• cords of important cultural events, political landmarks, terity the bizarre video comedy milestones of social history, of Ernie Kovacs, the somber and even classic comedy would, memorial to President John F. through neglect, simply disin• Kennedy, and Ed Sullivan's la• tegrate or disappear. Paley conic announcement that"sit• reasoned that some sort of an ting in our audience tonight institution should be built as " a repository, so he commission• The preceeding article was ed feasibility studies and reprinted from Du Pont Maga• seminars to find out if such zine, with the permission of an idea was practical. E. I. du Pont de Nemours and The conclusion of the stu• Company. Reproduction rights dies was -- yes! Miniaturized do not apply to this article. electronics and modern record• ing techniques could reduce a mountain of cumbersome materi• als such as radio recording discs, kinescope film and bulky videotape to manageable size. Plenty of material existed which could be collected and catalogued. That much being established, Paley did not wait for a length• y fund-raising drive. He con• tributed $2 million of his own money to insure the Museum's operation for its first five years. The doors opened in November 1976. The valuable collection, which is growing at the rate of about 4,000 programs per year, is stored in two vaults w ~~!~~~r:~:.:u:·:t~t~~~~~ ~ ini: r~7lh· Ci..•crimin.:irin~ ptt'f'!c. !i.1:1l,.-navox is that are about as close to be• cnuin fO ec i~ul!cci. ing completely burglarproof ~~~~i- ..l:fi'!!i~-;~~~~R~u~:-;, t:i.e :aJ.:!11..:.n of :a ~b,_....,,, .._ F<:>o<~ A m:."!.~ "'fTllcs as possible . Temperature and 1h.c<>Ch.,.,,rcqt.1tt.11<,.•olu:m-. ~- ... ,.,._~ ,_ ... lt,o.; ·-""'" r:- humidity are carefully con• ...... o...._..._: ..... i.-.:.~ ...... -=--...... trolled. Windows of the building are bricked over, not only for added security, J\GNAVOX but also to prevent any stray magnetic fields from affecting !Radio the tapes. All wires are care• .Reproducer Supreme fully shielded; none is placed ?lie 10 Background Material: Rath• er than reprint much of the al• ready printed literature on horn speakers, this article will reference a few signif i• cant articles on the subject, touch on some high-lights of horn speakers, describe the author's collection, show some frequency characteristics of horn speakers, and list known manufacturers . The reader may know of other good reference material, but the author recommends the follow• ing three articles for pre• ferred reading: "Early Horn Speaker Development," Old Timer's Bulletin, December 1976, Vo l. 17, No . 3; "What Is a Good Loud Speaker," Fred Canfield, Radio News, August 1928; "Loud Talkers," Walt Sanders, Radio Age, January 1978. Horn Speaker Popularity and EvolUITon of Design: The e:ra• for the popularity of horn speakers was . 1922 to 1926. Be• fore 1922, earphones were the common listening device. Dur• ing 1926, the paper-cone repro• ducer became popular , and by 1927, it was difficult to find horn speaker advertisements in radio magazines. Early horn Horn Speakers speaker designs were trial-and• error oriented . Early horn speakers tended to be straight• by Floyd A. Paul line v ertical cone-shaped tubes, with a right-angle turn to a Horn Speaker Definition: bell opening. Improvements oc• The horn speaker is a device curred by curving the cone• to reproduce audio sound waves shape tube of the horn into a from electrical energy and dis• continuous curv e. This design tribute the acoustical energy improvement was to become the through a horn-shaped element. basic shape of most horn speak• Horn loudspeakers contain two ers. Two benefits occurred elements, a signal reproducer from this continuous curving: and a horn-shaped acoustical The curved shape created a coupler. When the signal re• longer air column and a larger producer (phone or loudspeaker air column (more volume} and unit} is driven by electrical it was possible to move all energy, a diaphragm is vibrated masses of the mechnaical de• by a magnetic field (directly sign toward or over the center or indirectly} and an acousti• of gravity, and hence greatly cal sound energy is delivered improve the physical stability from the diaphragm. The col• of top-heavy horn speaker de• umn of air in the open horn sign. tube is displaced, creating amplified audible Sounds. Designs were copied and many Neglecting other parameters, innovations occurred during the the acoustical volume will be first few design years. New ma • somewhat in proportion to the terials were continually being size of the horn and the amount experimented with, in the con• of air displaced by the dia• struction and fabrication of phragm. horn speakers, and advertise- II ments exaggerated all types of the volume of the lower audio benefits from these modified levels but may limit the louder designs. Some manufacturers audio signals because increased made all parts of their horn diaphragm movement may cause speakers, such as Western Elec• the diaphragm to chatter a• tric and Magnavox, while others gainst the magnetic poles. made some parts and bought (2) Driver Arm -- Somewhat from others, such as RCA. more complex than earphones, Horns were fabricated from fairly rugged, magnetic drive wood, laminated wood, pressed of an armature which is coupled wood, bakelite, plastic, alumi• mechanically to a diaphragm, num, cast-iron, brass, copper, diaphragm of mica or alumi- papier mache and sheet-iron. num or bakelite, coupling is a The following design features rod or pole, subject to mis• and attendant benefits became alignment with use and aging, guidelines to good horn speak• and may result in possible pole er design. chatter, difficult to clean out (1) In general, horn ma• magnetic particles that accumu• late in magnetic field areas, terials should be made of fibre no simple mechanical volume or non-metallic substances control can be used, higher which have no natural period volume, fair efficiency, me• of vibration in the audio range. These materials do not exhibit chanical linkage can be reso• a ring or resonance, which many nant. metal horns had. (3) Voice Coil Driver Somewhat complex, alignment of (2) Horns should have dynamic parts important, hollow roughened interior surfaces, such as wrinkled paint on coil suspended in a magnetic metal surfaces, which tend field, coil coupled mechanical• to diffuse the sound and re• ly to a diaphragm, mica is the typical diaphragm material, duce metallic ringing. subject to magnetic and non• (3) The shape of the horn magnetic particles lodging should be exponential rather between moving coil form and than straight line (megaphone) pole pieces, better frequency shape, for optimum reproduction response than drivers and ear• of sounds. phone, higher volume. (4) A longest column of air in the horn (longer horn) gives Author's Collection: The a better low-frequency response. author has-a collection of 12 Short horns have higher cut• horn speakers, and one addition• off frequencies. al speaker which may barely qualify as a horn speaker. The (5) A largest volume of air Reflectone speaker is a bit of in the horn design gives a a maveric, but its possible greater volume of sound. qualification is based upon the Horn Speaker Driver Mechan• horn speaker design concept of ismS:-There were three basic an air column driven by a driv• driver mechanisms by which most er unit. See fig. 1 for a designs could be classified. sketch of the Reflectone de• The benefits, limitations and sign. The cross-section shows characteristics of these three how the sound from the earphone types are described here: located in the base facing up• ward impinges upon the internal (1) Earphone -- S~mple de• surface of a ll:i" diameter re• sign, seldom if ever need ad• flector cup, then is reflected justment, magnet drive to an backward onto the inside sur• iron diaphragm, fairly rugged face of a larger 3" diameter and not easily damaged, limited cup wrapped completely around frequency response from the the smaller internal cup open• diaphragm, limited volume, vol• ing and reflecting sound out• ume control (when used) is an ward through a grating to the adjustment which moves the listener. There is an air col• coils and magnet closer to umn, small as it is, with a and further from the diaphragm, definable length (about 4"), but when moved closer increases and the speaker's design is to 12 move a column of air into two Evaluation and Performance reflectors, which in effect Test: To get some comparative simulates an air column of a performance evaluations of the horn speaker. author's horn speakers, a test was designed and performed by putting a known frequency of a known intensity into each REFLECTONE speaker and making an intensity Reflected'- design sound level reading at a given Sound ' distance from each speaker. "' The test equipment consisted of an Audio Generator, AG-3, fig. 1 made by ~easurement Engr. Ltd. of Canada, a General Radio Au• dio Frequency Microvolter, Type Sketch show s 546-C and a Hermon Hosmer Scott how sound energy Inc. Sound level meter, Type from diaphragm is reflected off 410-A. The sound meter is a inner half shell commercial device for testinq sound levels and has a flat · frequency response of +l db throughout the audio range. It reads directly in db from 35 db (a very low whisper) to 140 db (which is above the The author's collection of threshold of pain for most horn type speakers is summariz• people) . The audio oscilla• ed in Table 1. Useful infor• tor supplied a 2.2V ac signal mation is supplied in this ta• at all audio frequencies into ble to help in describing some the General Radio Type 546-C of the pertinent characteris• Microvolter. The Microvolter tics of these speakers. The was adjusted to provide a 1 column titles are listed as volt ac signal output at all follows: The type of driver frequencies into each speak- column identifies each speaker er in this test. Two fre• as having one of the three quencies were chosen, and all driver mechanisms described speakers were tested at 350 earlier in this paper -- namely hz and lK hz. Any very pro• earphone, driver arm or voice nounced resonances and nulls coil. The bell diameter column (anti-resonances) were looked gives diameter to the next• for between 350 and lK hz and closer whole smaller inch. The noted. The sound level me- de resistance is accurate to ter was located 2 feet direct• about +10%, as is the ac impe• ly in front of the horn bell dance measurement, which was openings. The results of the made by using a 4V ac signal test are given in Table 2. at lK hz and driving a General Background noises from the Radio Decade resistance box, street and dogs barking in• type 602 L in series with each terfered with measurements speaker's driver coil. The de• below 45 db. Therefore, low cade box resistance taps were level measurements should be adjusted until the voltage considered marginal in accu• across the decade box equalled racy. the voltage across the driver coil and the resistance value There was a vast difference was noted. A Micronta 22-204 in efficiencies of these speak• multimeter with a lOV ac scale ers, as can be seen by the db was used to make voltage mea• measurements. A statistician surements. It can be seen will also advise against quot• from the measurements that ing data based upon one sample ac impedances of the various size in a test, and particular• horn speakers varied consider• l y when the tested devices are ably (3K ohms to 40K ohms). over 50 years of age. However, The table shows that most of the data should be at least the speakers have an ac im• considered as a q~alitative pedance to de resistance ratio result, if not quantitative . of between 5;1 and 10;1 at lK Two speakers were chosen for hz. an o v erall frequency response 13 ed and siezed, and no adjust• ment could be made. Therefore, the AK speaker response should not be considered as t ypical of a good AK speaker. Mo st of the horn speakers had a f re• quency response that dropped off rapidly below 250 hz, on the low end, and about 2.5K hz, on the high end. One horn - '"·U ' l·····J speaker, the Rola, responded . ':'f. l·L " 1' .. · : ::.+ well at up to 4.5K hz. Three of the speakers with earphone drivers had volume controls .... •.·_.,,·1 which varied the spacing be• tween the magnetic poles and I the iron diaphragm of the driv• ·'.. it' '.· I er unit. The Radiola volU1'1e control gave a 3 db delta i n volume . The BTH control gave FREQUENCY (in hz per sec.) over a 20 db range of volume. The Dictograph speaker control Frequency Response Curve gave a 15 db range adjustment. of RCA Radiola and 14" The WE lOD had no significant Music Master resonances. The Silvertone speaker had a generally in• creasing db response slope fig. 2 from 350 to lK hz (smoother measurement, and the test re• than most speakers) . Two of sults are shown in flg. 2. It the speakers had a v ery pro• can be seen there are many nounced dip (anti-resonance) peaks and dips in the response and these are so noted in the curves. The frequency response table. The Radiola UZ 1325 between 250 hz and 2.5K hz is could not be adjusted for a anything but linear. It should maximum output. It was not possible to turn the earohone also be pointed out that this clos~ tes"t which selects a standard mechanism extremely to testing condition for all the diaphragm, so as to achieve speakers doesn't necessarily maximum volume. Some parts may give results that might not be have aged and caused mechanical altered when a speaker is binding. The Magnavox R-3 coupled to a battery set's speaker was o p erated in this final output circuit. Let test with 6 volts applied to the reader be reminded that the field coil. The amperage the impedance coupling charac• was 1 amp at that voltage. To teristics of the final driver test the effectiv eness of the tube would also affect the vol• field coil a decreasina field ume output of the speaker, so voltage was applied to , the R-3 that, for a given driver tube field with a 700 hz signal ap• with a ~iven Ep/ Ip condition plied to the reproducer's voice and a given speaker's non• coil. The frequency of 700 hz linear impedance response, was chosen because the R-3 there would be a different peaked and responded well at audio output reproduced for that frequency region. As the the listener. field voltage was reduced (and hence current), no noticeable Observations: A few obser• decrease in sound volume was vations are in order about the discernable down to the half• testing of these various speak• vol tage point (3V), but as ers. The AK "H" horn speaker voltage was reduced further, did not respond anywhere near very noticeable sound level the db level of the other changes were noted. With 2V speakers, but the AK could applied to the field coil, not be restored or adjusted greater than 6 db reduction as some others were, since was noted. Below 2V the drop the pot-metal parts in the off in sound level continued base of the speaker had expand- to be pronounced 14 Photo1ra~hs: Six photo• early Magnavox horn. It is one graphs o t e horn speakers of the prettier horns in the are shown and referenced as author's collection. pictures l through 14. Descrip• Picture 8: The RCA Radiola tive comments are included a• UZ-1325 has a molded rubber bout the various speakers in horn and a volume control. It the following paragraphs. Pic• has a more upright shape than tures 1 and 2 show the smallest most other speakers. and largest horn speakers in the author's collection. Picture 9: The Rola, Re• Creator, has an aluminum horn Picture 1: Reflectone 3 11 and was in fact one of the diameter speaker (which the better sounding horn speakers author describes as barely of the collection. The fre• qualifying as a horn speaker) quency tests of Table 2 show is at least an oddity. Being the horn had better volume at extremely small, using an ear• 350 and lK hz than most speak• phone as a driver unit, it has ers. a very low audible output. It is made of simulated tortoise Picture 10 : The Dictogrand shell and was advertized in is an earphone-type horn speak• Radio News Magazines of 1925. er, with an adjustable volume This speaker weighs less than control. The ·numbered dial on l pound. the front of the chassis box, when turned, varies the air Pictures 2 and 7 : The Mu • gap between the magnetic poles sic Master horn speakers (14" and the diaphragm, thereby in• and 22" diameter bells) have creasing and decreasing the nearly identical goose-neck, pull of the ma gnetic field upon cast-iron bell support tubes, the diaphragm and hence its ad• .-but the two earphone driver justment varies the volume. units have quite different ac impedance responses at lK hz. Picture 11: The AK "H" is The 14" bell is made of light• a very ruggedly-constructed tan spruce wood (laminated), steel horn speaker, with brown and is original. The 22'' dia• crackled paint. The type of meter oak bell is a Victor driver is an 'earphone. The phonograph bell made of cross• aesthetic shape of this speak• banded oak veneers (Victor #31) er is most pleasing. Unfor• that had several inches cut tunately, the driver parts off the small diameter part of (made of pot-metal) had siezed the bell, and was custom-fitted up, and made adjustment impos• to the goose-neck part with a sible (note: a second AK "H" Music Master adapter ring. speaker was acquired during Since the 22" diameter bell the writing of this article, seemed to closely match the also had siezed parts and did shape and size of the original not perform adequately) . 21" diameter Music Master bell, Picture 12: The Western it was included in these tests Electric, 100, has a heavy for comparison and tests. metal base which contains a Pictures 3 and 6: The Magna• step-down transformer to drive vox M-20, Moc:.'l. A., is a unique the low impedance driver arm construction shape, being best assembly. The papier mache described as a driver arm re• 14" diameter horn is a bit dis• producer coupled into a u-shape torted on the edges because of cone-tube. The horn is totally time aging and wear. The horn encased in a walnut, rectangu• is one of the earliest of all lar box cabinet, with a cloth shown in Table 1. It weighs door cover. 9 pounds. Picture 4: The Magnavox R-3 Picture 13: The British is an electro-dynamic speaker Thomas-Houston (BTH) is a with a movable voice coil an• British-make horn speaker with chored to a metal diaphragm. an earphone driver and an alumi• The movement of the coil is num horn. The outer bell is limited only by the elastic painted brown, and the volume limit of the diaphragm. The control is a knob in the base impedance of the coil is very that gives an extreme range of low, so that a step-down trans• control . (over 20 db) . The former needs to be used from tonal quality was as good as the output of an amplifier. any US-make earphone horn. The electromagnetic field con• Picture 14: The Sears Sil• sumes lA at 6V. Resonance of vertone WLS horn is one of the the diaphragm is hear 4700 hz. smaller horns, having an 11" This speaker is the heaviest diameter bell . The horn is of all the author's speakers, molded bakelite, brown-colored, and weighs 13 pounds. with a very low driver de re• Picture 5: The Magnavox M-1 sistance and ac impedance. has a driver coil res i stance of In conclusion, the author 400 ohms, and impedance at lK has made a listing of horn hz of 3K ohms, the lowest of speaker manufacturers and all speakers tested. The steel model identifications of the bell is painted gold, one of 1920's, and lists 65 such manu• two colors available with this facturers in Table 3. 15 16 Table Manufacturer Model-Name-Style Ackerman Aristocrat 21, 25 Ajax Elect. Spec. Aldine Radio & Mf. Microphone American Art Mache Madera Amp lion AR 102, lll, 114, The Midgtit Dragonfly, Jr., Loud Spt111ker Jr. deluxe (also With the identified as AR Cinnl Voice 15, 19, 35, 45) Arkay American Elect. Burns 205B, o Atwater Kent H, L, M. R -and only 5 inches high Baldwin Nathaniel Bel Canto W 1 ;1'. '.~ '. ~1~~::'. ' ~ ~ ~ : . ~~:; i11 :' ;;: :' i:t 1: ;::: :.'.;;::: . ;: 1 ·. :.:l~1~· 1 ;;:::'.:;:'.:\~:·:'. :,:\s .'.~::i Brandes Audiophone "S, 11 •111 .1 ll1 w--th.11 tlwlu•11 11· ha. lou1 i.:11a t111·,I . "J, 11 Baby Grand , Tiu- f<:dl• ••'lu•,,. •• m:ul1· 11.. 111 .1 lw .1 11 1itul. hi~ hl ) 1'"1,,1,,.,\ nrn t1·1i.ol •i111 ul:i 11U;! l•>th •i•1' -111·[ 1. Baby lt-um1-11:i ltw1.d 11 11 .1li11 i- 1li1· 11 ·- ull u1 1li,•l.<11·t·•·i,·111 i1i.: Bristol R 1202 oh ·1d,,1111w111 11IU' lt'h) .,,,.1,.I ;, l<'lln•tt•ol 1110111 ••1u· ,!••11:11 Cannon & Miller Cameo d1:1111h, ·1 l•• :n 1•otl,.·1 . ' l'loi. 11w1h. ,.l .. limi1 1.ol• '• oli• t Type Bell (ohms) ac imp. of dia. de (ohms) at Mfsr. - Model Driver in in. resistance lK hz Atwater Kent, uH" earphone 14 2,000 lOK British Thomas- earphone 14 2,000 12K Houston, BTH Dictograph Prod., earphone 10 4,000 40K Dictogrand Magnavox, M-1 driver arm 14 400 3K Magnavox, M-20 driver arm 8xl4 1,800 7K Mod. A Magnavox, R-3, voice coil 14 1,400 7K Mod. B Music Master, 14D earphone 14 1,200 13K Music Master, 22D earphone 22 1,400 6K RCA, Radio la earphone 12 1,800 16K UZ-1325 Rice & Hochster, earphone 3 1,100 12K Ref lee tone Rola, Re-Creator driver arm 14 2,000 16K Sears, Silvertone driver arm 11 800 SK Western Elect. lOD driver arm 14 1,000 24K Table 1 DECIBEL LEVELS OF HORN SPF.AKERS WITH RESONANCES AND ANTI-RESONANCE POINTS Anti decibel level at Resonances Resonances Name 350 hz lK hz Freg. db. Freg. db. AK "H" 40 40 BTH 64 57 640 74 360 68 Dictogrand 52 59 540 68 380 64 Magnavox M-1 55 75 650 80 Magnavox M-20 44 57 700 50 Magnavox R-3 50 72 750 74 650 74 Music Maste r 14 II 62 67 700 70 Music Ma ster 22" 59 63 950 67 700 67 450 67 RCA UZ-1325 55 54 600 70 Ref lee tone 40 62 Rola 58 72 380 45 Silvertone 49 62 540 58 400 46 Western Elect. l OD 48 60 Table 2 18 The Fate of Rufus McGoofus By J. H. Reed .Rufus McGoofus knew radios hy heart; Beautify That Old Radio He could put them together- or take them apart. by Edward W. Sage A handy mechanic was he to han~ 'roun 19 Philo T. Farnsworth by Kenneth W. Miller in the Navy until his father's death in 192A. He then return• To say that the name is not ed to help support his mother, a household name is definitely and managed to attend classes an understatement, but in 1930, at Brigham Young University. at the age of twenty-four, Phi• But before long his part-time lo T. Farnsworth was granted job ran out, and he moved to the patents that are the basis Salt Lake City to open a radio of modern television. In fact, repair shop. However, the Philo Farnsworth was sixteen shop was not a success, so in 1922, when he diagrammed Farnsworth went to work for his plans for electronic tele• Community Chest. His employer vision on a blackboard in his was George Everson, a profes• high school in Rigby, Idaho. sional fund raiser who adminis• tered Community Chest campaigns In 1926, Farnsworth began throughout the Western states. developing his ideas into an Everson was impressed with operational system in a labora• Farnsworth's ideas for elec• tory in San Francisco, Cali• tronic television, and arrang• fornia. At the time, similar ed the $5,000 Farnsworth efforts ere under-way by v. K. thought it would take for a Zworykin at RCA Laboratories working model. in Camden, New Jersey. Mechani• cal scanning television was, of Farnsworth moved to Southern course, already in existence, California, where he would but Zworykin and Farnsworth have access to the California were developing systems in• Institute of Technology. But volving electronic scanning. after a · few months the $5,000 Zworykin had the facilities was gone and Everson had to and finances of RCA at his dis• stump for more money. Farns• posal, but Farnsworth worked worth now estimated that he independently with a small needed an additional $12,000. staff on a fraction of Zwory• So, a somewhat wiser Everson kin's budget. There were started looking for $25,000. countless problems to be That support finally came solved and Farnsworth made from w. w. Crocker of Crocker advances in a variety of Bank and other investors in fields. After mastering the San Francisco. Farnsworth special glassblowing problems, then moved into a loft owned there were details like making by Crocker Bank at 202 Green a photoemissive coating only Street in San Francisco to one molecule thick on the continue his work. face of his scanning tube. Farnsworth eventually earned The air of secrecy that sur• more than 165 patents cover• rounded the experiments led to ing the entire spectrum of a raid by police, who found the engineering and physics, and strange glassworks, but not the including the fundamental still they expected. Then, on• television patents for ~can ly one year after moving into ning, sychronizing and focus• the laboratory on Green Street, ing. Farnsworth succeeded in trans• mitting electronically-scanned After high school, lacking video images. It was the fall the funds to attend college, of 1927, and he had just turned Farnsworth spent a short time twenty-one years old. A slide 20 with a hand-painted triangle those days, including Zworykin was placed in front of the himself, who expressed great crude camera, and a few yards admiration for what he saw. away the blurred outline of RCA was becoming painfully the triangle appeared on a one• aware at this point that they and-a-half-inch screen. After would have to deal with Farns• this beginning, Farnsworth worth, as dreams of a complete• quickly improved the quality ly independent RCA electronic of the picture and succeeded television system went up in in transmitting a film clip smoke. It wasn't until 1941, of Mary Pickford combing her however, that Farnsworth won hair, in a scene from "The a long-standing suit with RCA, Taming of the Shrew. " which awarded him the basic patents . RCA's patent attorney In September 1928, the ori• is said to have had tears in ginal budget of $30,000 had his eyes when the royalty a• been overrun by 100%, and it greements were signed. was time for a public demon• stration. The Mary Pickford Farnsworth's San Francisco clip was included in the demon• days came to an end in 1931, stration, and it was said that when his company reached an a• she combed her hair a thousand greement with Philco for the times that year, in demonstra• production of television re• tions of Farnsworth' s tel·e• ceivers. The agreement includ• vision. Farnsworth caught RCA ed the stipulation that Farns• by surprise when he applied worth move his lab to Philco for a patent for the system. headquarters in Philadelphia. Farnsworth's lab had a num• In 1938 Farnsworth's Television ber of impressive visitors in Laboratories bought Capehart 21 Radio and began plans to pro• RESTORATION HINTS duce their own television sets. The company became Farnsworth Most Grebe receivers I have Telev ision and Radio Corpora• come across have the fine-tune tion, based in Ft. Wayne, In• rubber friction drive flattened diana . In 1948 the sets came or hardened with age -- such off the line, but proved an that they will not turn the irr~ediate failure. By 1949 main dial . The way I repaired the company was bought out my Grebe CR-8 was to loosen by ITT, and Farnsworth became the main components from the President of the Farnsworth panel and remove the fine-tune Research Division. He remained wheels. Care should be taken with ITT until his retirement not to do any soldering if pos• in 1967, and on March 11, 1971 sible . Also use the best fit• he died in Salt Lake City . ting screw driver available, so as not to nick the black Farnsworth was one of an screw heads. Remove the old almost extinct breed. In an rubber 0-Ring from the grooved age of corporate research and wheel . Fill the groove with large budgets, he was the ro• small rubber bands {or string mantic maverick inventor work• or smaller 0-Ring), to bring ing by his own wits, with in• the surf ace of rubber bands dependent financing and limited budgets. It's saddening that approximately flush with the he never escaped relative ob• top of the groove. Then take a 1/2-inch (3/8-inch inside scurity. Only with the coming of the 50th anniversary of his diameter) rubber chassis grom• 1928 demonstration, has some met and slip it over the groov• recognition been given Farns• ed wheel . The outside diameter of the rubber grommet is iden• worth. Ceremonies in late 1978 included one at Foothill tical to the original Grebe College in Los Altos, which rubber 0-Ring and fine-tunes as smooth as silk. featured a re-creation of the original setup and demonstra• tion . In addition, a plaque was placed on the building at 202 Green Street, where Farns• worth helped give birth to modern television, more than 50 years ago. An excellent reprint of an early Crosley Radio Apparatus Catalog is now available. It contains many illustrations of various sets and parts, ranging from the model XXV to the small experimental units. The cata• The preceeding is based log is 32 pages in length, and largely on the book by George is priced at $4.00 + 50¢ for Everson, titled The Story of mailing. You may order it Television: The-r;Ife-or-Philo Farnsworth~NY , Norton~, ~ - from Vestal Press, PO Box 97, T . 320 North Jensen Road, Vestal, 1949), as quoted in Erik Bar• New York 13850 . nouw's The Golden Web, {NY, Oxford Uiliversity Press, 1968). vestal Press also has books Also a magazine article, "Tom on automated musical instru• Swift in San Francisco," by ments, juke boxes, phonographs, James Minton {November, 1972, gambling machines, etc. Write San Francisco Magazine). for details. 22 @ by Don Stoll T ime Switch This issue I've tapped into An automatic device made in the form of an owl, for automatically shut• the extensive collection of Jim ting off t he radio r eceiver , has been in• Cirner and come up with two of troduced by the Radio Owl, 2269 East his treasures that I really like . 5 lst Street, L os Angeles, Calif. This instrument will operate on either A .C. The first is the "Radio Owl" or battery sets. Its operation is h y • draulic and may be set for any period which was advertised in Radio from 5 minutes to 1 ~ hours. The switch Retailing in 1928- 1930 and sold has a capacity of 5 amper es. It is to for $3.50. Standing about 6" be installed in series with the A-supply with D.C. sets and on the 110 volt side high, and weighing almost 2- lbs, of A.C. sets. It is about 5~ in. high and this finely detailed statue is fi nished in brown. T he intended r etail price is $3.50.- Radio Retailing, August, cast of heavy metal with a 1928. hydraulic and spring mechanism that can be set to automatically turn off your radio up to 2- h rs after activating . The bronze color finish on the owl is very attractiv e but the plastic eyes are not as well done as the casting (perhaps they should have been lighted). If anyone out there has one of these birds and would be willing to part with it, please let me know. "Hauschildt Music Company , Oakland". The bottom front edge of the cabinet pulls out and becomes the handle of a roll (approx . 14" long ) of impregnated fabric with an alphabetical- log sheet printed on one side and a one-week daily "favorite programs" log sheet printed on the other side . The original owner had written in west coast stations (KLY, KGO, KFRC, KTAB , KEX , KNX, KLX, KF I, KECA, KQ\·1 , KSL, KFWI) and programs such as News Item-KLX, The second item from Jim's Amos Andy- KGO, and Cecil collection is an unusual pro• & & Sal- KPO. This r adio novelty motional device that I can ' t was manufactured by Midland find mentioned in any of the Specialty Corp.-Des Moines, Ia. early publications. It's a miniature model of a radio set If you have any interesting (probably battery) , 4"-wide , radio novelties, please let me 2" - deep, and l~" - high. Made know (a quick picture is good). of sheet metal with dark- brown Write: Don Stoll , Foundation XIV, crackle finish , the top of the 2245 Old Middlefield Way, cabinet is imprinted with Mountain View, CA 94043. 23 Jim Eni!land I began my radio collecting about 18 months ago. It all started when I walked into an "Antique Store," where I no• ticed my "First Radio." From that time on, I attended auc• tions, garage sales, etc. My collection totals 30 radios, at present. My reasons for settling on "Cathedrals" seem to center a• round their design. It quickly became apparent that there are many different "makes and models." Each "new radio" I find is a new experi• ence. And, I might add, a very enjoyable one! As fellow radio collectors know, some of the more prominent names in "Cathedral Radios" are: Phil• co, Atwater-Kent, Jackson-Bell and so forth. As time passes, I plan on "branching out" my radio col• lecting. I enjoy collecting literature on radio gear, as well as pictures, etc. Jim England 6875 Escallonia Drive Orangevale, CA 95662 (916) 725-6625 ps: I am currently looking for Atwater-Kent Cathedrals, especially: Model 558, Model 82, Model 84. 24 TECHNICAL SPOT MIOHTY MOHAR.CH OF THE AIR. Help! ! necessary to cut or unsolder several wires to remove bottom Have you ever restored a plate. I don't feel that it Majestic radio model 20, 21, is practical to attempt to re• 22 or 23, manufactured by cap capacitor pack. If you Grigsby Grunow Co. , year 1931? r econnect capacitor pack as This radio is a very diff i• originally designed, the ra• cult chassis to restore for dio becomes unserviceable a • several reasons. The large gain. Yo u could extend all power supply capacitor pack, the wires from the pack, but the power supply choke and this might cause oscillations, the output transformer are all etc. This is the way I sug• mounted on the bottom plate-.~ gest you restore it. Look In order to expose inside of chassis, remove both sides first (fig. 1). Then it is Figure 1 cap pack ~~~~- output trans. ~~~~~ ---1111111!!~:;--...,.-;...:..,...;._ ~~.e:;;..~ ,-,:t- ~~~~~ ....:..,:t-'- ~ 25 c HOl<:e Mouli/Te.d 0/11 SOTTOM cover- SPI<., FleLO Pt/II 2 OF PIN 3. OF COi L \ To To'lle CONT l"'O L. :>..7 rvse f.{.S- TVBGS !Sec. oer. J_ 'f"' 8L •04' MFO. ~40V .s 1 ff "f 1wre1- ' RF CHOke '· 7"' SO M .H .. :l..00 ..J"L- ... + llK eLeeoe.,. N e l \.VOt-1< Figure 2 at my schematic (fig. 2), it is safe to lift terminal showing what is in the capaci• strip higher. Cut all the tor power pack. You will ob• old capacitor wires and cut serv e there is a 200 MH RF the interstage transformer choke between terminals 7 and wires as long as possible . 8. Remov e brass 6/ 32 screw Take a 500-degree F. on terminal strip. This screw shrink-tubing heatgun and melt helped held RF choke in place the tar around t h e RF coil. when unit was being manufac• When it loosens from the tar, tured. Carefully pry up ter• remove it from pack. This minal strip slightly. You will be able to see RF coil wires connecting to the under• Figure 3 side of terminals 7 and 8. Disconnect these wires . Now 4 MFD caps ------.... 25 K------...... _< 26 will be reinstalled elsewhere as shown (fig. 3) and wire to later. If the interstage new capacitor pack. transformer is good, take a NOTE: The two . 1 MFD 200 pair of tin snips and cut the VDC plate bypass capacitors metal side of the capacitor are potted in tar, one in each pack case from one side of IF transformer. It is neces• the transformer. Use a heat• sary to remove IF transformers gun to melt tar away to re• from set and carefully remove trieve interstage transformer. rivets. Heat IF cans and pull Throw away the rest of capaci• the IF transformers out of the tor pack. If you don't have melted tar. Throw the tar a• a heatgun, heat the pack in an way. Remove old plate bypass oven. This takes longer and capacitors. Suggest you in• is messier. The 25k resistor stall new ones outside IF cans, between terminals 1 and 5 one on either side of the 500 should be sav ed for later use. ohm resistor as shown in sche• As shown (fig. 3), mount a ma tic. terminal strip on side panel Remount speaker output of chassis. Install four 4 transformer on front side of MFD at 450 VDC, and the origi• chassis (fig. 3), on power nal 25k resistor to the new transformer end and rewire as terminal strip. It will be shown in schematic. Speaker necessary to extend a few wires cord wires are the old rubber• to connect up the new capaci• cov ered wires, and will probab• tors. l y require replacement. Re• Also, make up a mounting align IF transformers if neces• bracket and install the inter• sary . IF frequency is 175 K. state transformer on the side HZ. This set is a lot of panel. This allows you to be work to restore, but you will able to lower side panel and discov er it is a very good make the rest of the components sounding radio. Don't forget serviceable. Remount the RF to check the resistance on choke near the tone control. all resistors, coils, etc., Remove all the old capacitors for possible problems. If and replace with new ones. any further questions, contact Mount the power supply choke me: Jim Cirner, 13366 Pastel Lane, Mountain View, CA 94040 (415) 967-7672. 0 80 0 o s10 O o si 0 '"° 00 45 MOvtlTed 0 21() Cl Ci" .."' Cl c:"' ~ :!; 8 !. ~:. \:~ . - Tube r tl .V. Pl t . V. Crd .V , C•th. v . Sc . Gr d.V. Plt.CrDt lR F 2 .32 180. 3. 90. 6, • 1..1 .... (( RO 2 .32 90. 4, CCIN Dt>I SE.:i: COLOR CODE o. c. o. 2 .~ 2 2 1114 oomdens•r- Or•np .atr&nd eG tDet 180. e. to. 1. 2 at'd c o 11denser- ~hi. e, • t rand-.d lIF 2. 32 UIO. 213. 90. 5. l atd corid e nu r - Red , strand -.:S MAJESTIC. : ~ = ~ ~:! ; l 11fd con ~ e n ser- Gr e .tn s t ra..b ded ;;;: 46. 2:: e ondenser co=.on- !:ll e.o lc s t r•nd,d 21·2.l.·l.!> ,,...,. 2.35 " ' · ••• 28 . . C1 • !°d '- ond en.H r - lli" hi t • s tranded ••(L 2.0 C.MUStl Rec . 4 °88 41 0 . 80 • 27 wireless use. after Edison experiments. Marconi used the Fleming Valve in some of his early re• ceivers but it was soon sup• planted by the· electrolytic detector which was more servi• ti ve . The Valve is nothing more than a two-element vacuum tube. Many versions were made. As it had a very limited applica• tion, not much can be said a• bout its characteristics. Sizes and shapes varied con• siderably and, since they were hand-made, it follows that filament voltages and currents v aried widely . Many claims were made for The Fleming Valve two-element tubes using an ex• by Russ Winenow W6AVG ternal grid. Various circuit arrangements were recommended, John Ambrose Fleming was all of which s howed the exter• born in England in 1849. In nal element connected to the 1882 he was appointed to the antennae. I have tried sever• Edison Electric Light Co. of al of these, but was never suc• London. While there, he pre• cessful in making any of them sented a discourse before the work. Royal Institution on the prob• lems of the electric lamp. He A much more detailed ac• also reviewed the work of Edi• count of Fleming's life may be son and confirmed the rectify• found in the "Scientific Ameri• ing properties of the lamp can" magazine of March, 1969. with an added element. In Time prevents me from adding 1896 he.wrote a book in which more details, which the reader he noted that Hertzian Waves can find in the following re• had been suggested for use in ferences: Wireless telegraphy. In the same year, he gave all honor "Conquerer of Space," Cor• to Marconi for being the first n eal, Liveright, N. Y. to demonstrate the practical• "Father of Radio," DeForest ity of using Hertzian waves. Autobiography. In 1899 Fleming joined the "Fi-re of Genius," Heyn, An• British Marconi Research Staff chor Press. and built a special transmit• 11 Marconi, 11 Degna Marconi , ter for the famous Poldhu-St. McGraw-Hill. Johns transatlantic tests. He "Radio & TV Almanac ," Dun• applied for a British patent lap. in 1904, which subsequently "Modern Wonder Workers," was assigned to the British Kaernpffert, Blue Ribbon. Marconi Co. The patent was "Radio World Magazine," June for what he called an "oscil• 17, 1922. lation valve." The British "Saga of the vacuum Tube," still ref er to tubes as Tyne. 11 valves." CORRECTION: The following typ• Contrary to some accounts, ing error appeared in the last he did not simply make use of issue, under the Tube Column. Edison's discovery. He did a After the heading 1927, the GE great deal of work on it be• should read WE. fore he realized its potential submitted by Lauren Peckham 28 Electronics in the West -• THE MAGNAVOX LOUD The First Fifty Years SPEAKER This loud speaker is the result of considerable experimenting and re· by Jane Morgan search in the design of radio loud talkers, and is an instrument that (pub., 1967; $3.75, plus tax) does not require any electric current for its field excitation. It is de• As collectors, we devote signed primarily for use with raclio considerable time to reading technical material, study ing schematics, and familiarizing ourselves with antique equip• ment by perusing catalogues, magazines, Vintage Radio, etc. Perhaps we tend to ne• glect a most important seg• ment of our hobby -- its his• torical aspects. Here is a book which will painlessly introduce you to the development of radio and electron ics in the San Fran• cisco Bay Area. The authoress makes no attempt to be techni• sets that employ dry cell tubes. Un· cal or provide an in-depth like the famous electro-dynamic type study of any of the great pio• employing an electro-magnet, this iu· n eers. Instead, she cov ers strument employs a powerful per· the period in 188 pages, by manent magnet for its field. It is touching upon the lives of called the Semi· Dynamic, type Ml, Magnavox, and is manufactured by DeForest, Herrold, Elwell, the Magnavox Co., Oakland, Cali· Farnsworth, Heintz, Kaufman, fornia. This instrument has a D. C. the Varians and many others. resistance of 400 ohms and an im· Herein you will find references pedance at 1,000 cycles of about to the Bay Area companies which 5,000 ohms. It is exceptionally sen• sitive throughout the wide range of appeared on the scene through• audible frequencies and reproduces out the y ears. You will also powerful signals without rattling. read the story of the Perham It is noted for its excellent quality Collection, its transfer to and faithfulness of reproduction, the New Almaden Mu seum, the The base and horn are of metal, highly finished in gold. formation of the Perham Founda• Arrived in excellent packing. tion and the transfer of the AWARDED THE RAD I 0 collection to the Foothill NEWS LABORATORIES CER• Electronics Museum. TIFICATE OF MERIT NO. 292. In summary , this is an easily -read brief history of the subject, amply illustrated and modestly priced. Sounds Uintase Copies available at: Foot• hill Electronics Museum, 12345 This is a new monthly maga• El Mon te Road, Los Altos Hills, zine, edited and published in CA 94022. England. The first issue just arrived, and as stated on the cover, the publication is de• voted to vintage wireless sets, phonographs, gramaphones, re• LEARN THE CODE AT HOME cords, news, history and books. This is an ambitious under• taking. In-depth coverage will be provided after I have had the opportunity to examine one or two more issues. Annual subscription b 6.80 airmail (approximately $13.60, based on current rate of exchange). The Omnigraph Mfg. Co., 20 H1dson St. , M1w Yori City - Dave Brodie 29 Raaio News for June, 1925 :Me Geutest Values in /(alhb 1/!sta.y Show us a nationally advertised headset or loud speaker (with a list price not greater than ours) which is equal or better, in any respect, and we will send you a Tower Scientific Loud Speaker absolutely free. On Sale from Co2lt to Co.. t. If your Dealer cannot supply you, order direct. THE~HOTEL Philadelphia The6rst 1003 Radio Equipped Hotel in the World. Tower Scientific Headsets were used exclusively WoRLJ1S GRE~TEST LounsPE~KER VALUES 30 Wanted: 1st Volume of the 4- Wanted: Riders Volumes 1-5 --voI. Set, "Everyman's Guide ------ruilabridged) and 20-23; al• to Radio" (1926) , published so information on obtaining by Popular Radio. Also, a replacement phono car• April 1921 issue of "Radio tridge for a Motorola Model News" with cover. Last, 58-FRC. I have Riders Vol• Pilot vernier dial (Green• umes 6-10, 12 and 17, and wood, pg. 204, lower right). a Philco Cathedral Model Floyd Lyons, 456 Post Street, 38-123 to sell or swap. San Francisco, CA 94102 Stan Lopes, 1201 Monument (415) 396-6866. Plvd.#74, Concord, CA 94520 (415) 825-6865. Wanted: Radiola 24 cabinet ----rICr or parts set. Grebe Wanted: Rider's Perpetual Synch 7. Has anybody re• -----orrouble Shooter's Manuals, plicated the pot metal end Vols. 1-16 plus Indexes. pieces for the SLF tuning Also need chassis to AK 49, condensers? Need WDll duds plus AK literature. Roark (bakelite base). Need ori• Vane, 6839 Havenside Drive, ginal owners' manuals for Sacramento, CA 95831. any make. Jerry Newton, Route 1, Box 262, Woodland, Wanted: Cabinet for Majestic CA 95695. Model 70 or if you cannot Wanted: Pre-1940 National Re• part with your cabinet, ceivers. For Sale: Non-oc• make me an off er for my tal tubes.--irested OK, $.50 chassis and speaker. Russ to $1.00, SASE for needs. Goodlive, 1401 Franchere F. R. Tesche, 3728 Mosswood Place, Sunnyvale, CA 94087 Drive, Lafayette, CA 94549 (408) 732-1472. (415) 284-5608. Wanted: Any model Elkay Re• Wanted: Grandfather clock ra• -----ceiver -- state condition, dios. Prefer Philco 70. price and model number. Want mint Freed-Eisemann Keith Parry, 17557 Horace Model 14 speaker, Philco 90 Street, Granada Hills, CA and Philco 51 clock radio. 91344. Sell ~ Swap: Hallicrafter SX-25 with matching speaker, Wanted: Metal tube can for Kolster 8-B and 6-J, Cros• ----OVS tube. Also need good ley 51 SD and ACE. Edward or bad DL4 tube without can, W. Sage, 559 Civic Center former for Crosley 51. Al• Street, Richmond, CA 94804 lan Bryant, 38262 Ballard (415) 236-8093. Drive, Fremont, CA 94536. For Sale or Trade: SE 1899, Wanted: Base and driver for ~-Ip-50l:A;"° English Crystal 24" Magnavox horn. Two Set, Federal 110, Crosley Bremer Tully variable capa• 51, Audiotron, Murdock Neo• citors in good condition, trodyne and others. Paul split stator type - 17 Giganti, 2429 San Carlos plates each section. Must Avenue, San Carlos, CA be in good condition. Sin• 94070 (415) 593-4723. gle socket for WE 215A pea• Free: Uncle Al's Radio "Mak• nut tube. Output transfor• ~~ers of Miracle and Melo• mer for Howard neutrodyne tone Radios" Service cards. (Model A). Transformers While they last! SASE for RADA and Radiola III. please. Scott Welch, 3167 Dave Brodie, 315 Cotton Eastman Avenue, Oakland, CA Street, Menlo Park, CA 94619. 94025. For Trade: Grandmother clock• Wanted: Member who has draft• ~-radio, Westinghouse Columaire ------rng equipment and ability, Jr. Model WR 12. Restored to re-draw schematics, etc., and in good condition. Jim to be used in the Journal. Cirner, 13366 Pastel Lane, Contact the Editor: Allen Mountain View, CA 94040 Bryant, 38262 Ballard Drive, (415) 967-7672. Fremont, CA 94536. CJ/ze 1 • J) A.• , ~mp_aon J:-'eulfi!ee \~~\\)\)\\I I I\' 'I I'\' '"'"" 11 ll'lH"' ull •lll\Ul llH I" 'I\)\ \l)Jl ))1\)))\ll In 1887 Mr. Alfred Graham invented and dem• onstrated the first ~ra';~~o~s~ ~~i d bad ever heard (illuatrated above) • Graham L ou d Speakers placed In 1894 GrahamLo ~d Y 1 Pu~f:.a~o~ ~~~~S Speakers first used m ...... I the "1893 model." British NavY. Graham Created by the actual originators and world's ~~~1::~~1;h~~~eyo~d oldest makers of loud speaker reproduction. speakers, it is only logi• In 1896 Grah am Loud Speaking Naval Telephones developed and cal that the Amplion adopted by British Admiralty. should "the world's In 1898 Graham Watertight Loud Speakers patented. Placed on many be warships and m ercantile vessels, throughout world. finest" radio reprodu• In 1902 Complete Graham Loud Speaker installations, on central bat• cer. Some of the coun• tery plan, erected on warships as sole means tries in which Ampli• of communication. In 1906 The most extensive loud speaking naval in- I· ons rule as favorites: stallation to date was made by Grahams. • Included a Graham exchange system fitted to UNITED STATES H. M. S. Dreadnought. DOMINION OF CANADA Onwards Graham Loud Speakers applied to all sorts and conditions of service a t home and abroad, ENGLAND ashore and afloat. SCOTLAND WALES By 1919 No Jess than 12,000Graham loud speaking installations in oper• IRELAND ation on ships alone. NORWAY SWEDEN 0 DENMARK f:UJ ~~a?e~ ~e~l~ l~n! ~Jo~~~ HOLLAND BELGIUM common use ) "AMP- standard equip- &;_ FRANCE SPAIN ;:~:~r'fo~ ~ d~e~ ~d~~~1~~ i~ SWITZERLAND Alfred Graham & Co. sets abroad. ITALY JAPAN 192 " AMPLION"trade- 1922 ftt SOUTH AFRICA Mod mark registered. Model ~ NEW ZEALAND Jn 1923 Amplions introduced into Unit,ad States, Canada and other AUSTRALIA countries. Quickly attained largest throughout-the-world sale of any loud speakers. In 1924 To supply demand The Amplion Corporation of America was formed to market and manufacture Amplions here. ~ 0 ~t!~: ~~ ~t C,Z~fS~~e~~~;~:~thgf~f:~~~~~!i .JlliL demand. 'fhe Amplion Corporation of Canada, Lim- ited, organized. Alfred Graham & Co., London, England Patentees T o hear this new cAmplion CJJra· AMPllON gon AR-19 is to appreciau why ;/heWorlds Standard .[oud Speaker c:Amplioru, yetJr after year, inter• ntltionally lead in 54/es. Six mo• THE AMPLION CORPORATION OF AMERICA dels, including phonograph units, executiYe Offices: Suite S, 280 Madison AYe., New York Cit) $1 210 $42.50. Write for interest• ing liurature and dealer's addreH. Canadian Distributors: Bumdept of Canada, Ltd., Toronto Associated Companies and Agents: Alfred Graham & Co., London, England• The Amplion Corporation of Canada, Limited, Toronto; Compagnie Francaise Am'plion, Paris, France; Compagnie Continentale Amplion, Brussels, Belgium; Amalgamated Wireless {Australasia), Ltd., Sydney and Melbourne; British General Electric Company, Ltd., Johannesburg and Branches; Indian States and Eastern Agency, Bombay and Calcutta; C. ). Christie E. Hijo, Buenos Ayres; David Wallace & Co., Valparaiso; Mestre & Blatge,Rio de Janeiro; F. W. Hammond & Company, London and Tokio.