AMATEUR 1920 OVER 100 I L LUSTRATIONS Edited B' NEWSREG

Radio Map of the !3, /924Y 15 Cents JANUARY RADIOAMATEUR 1920 OVER 100 I L LUSTRATIONS Edited b' NEWSREG. y.3.PAT.OFF. Hoe] I ?sback "The 100 Wireless Magazine"

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AMPLIFY YOUR RADIO SIGNALS OE of the greatest drawbacks since the invention radio signals to such an intensity that he can hear of wireless telegraphy is the receiving of weak the signals about his station without the need of the signals at the receiving station. Many devices were telephone head set. but without suc- proposed to improve this condition, By the addition of a loud talking telephone he is able to hear cess, on account of the mechanical difficulties encoun- the messages many feet away from the instrument. He is also tered in these ampli- able to demonstrate the fying devices. operation of his wireless However, this was apparatus to his friends. recently solved by the The super - sensitive introduction of an ex- DETECTAGRAP H- TRANSMITTER here- ceedingly sensitive mi- with shown is two and crophone transmitter, three -eighths inches in di- which is known to de- ameter, five -eighths of an tect sound waves with inch thick and weighs less than three ounces. It is great accuracy and the most sensitive sound magnify them through Practical Instrume nts for Commercial detecting device ever an intermediate tele- brought before the public. phone circuit. and Scientif is Purposes. The manner in which By the employment the amplifying process is of the new DETECTAGRAPH- TRANS- attained is by attaching with tape the DETECTA- the GRAPH- TRANSMITTER to the regular wire- MITTER, amateur can amplify the less receiver as indicated in the diagram. Other Uses -1 NOTICE is this instrument applica- Although prices of raw material and labor have in- Not only creased greatly in the last four years, we have con. ble for amplifying radio signals, but tinned selling our instruments at the pre-war prices it can be used with equal satisfaction due to the fact that we had a large stock of sounds. Phono- material on hand. That material is now almost for magnifying other exhausted and we will be compelled to renew our graph music can be transmitted from stock at an increase in price, but for a limited time one place to another by means of this you can still get the benefit of the present low Our Super -Sensitive instrument, and those who are afflicted prices. Detectagraph Trans- mitter. Price, $7.00 with deafness will find enormous Complete benefit by using this transmitter. It Is t h c Aflust.d Our 'tuner Sensitive loud to/king Moa.l tarn, slit Hs. greatest d e - 'B' laikie ///zropho e Tronjmd /er telephone v in e 20 h10h Arad. loud % for Recsioesa an building your Stand Búe. own loud Price. $12.00 Complete talking tele- Adiuted rG phone, detec- /lead Jet, tagraph and Model 'C" Rhea-tot, other devices. Horn, w I t h Can be used N o . 20 high IlOd/rf/ for any pur- grade Lou d pose where a Talking Wall sensitive de. Receiver. i tecting i n - Price, Our Special No. 25 Detector Our Seruihve toco Ohm strument is Loud Talking Receiver Rodio Telephone Receiver required. Price, $4.50 Complete $12.oí, C,,,,, pl.t. DETECTAGRAPHS FOR THE EXPERIMENTER FOR DETECTIVES FOR THE DEAF DETECTAGRAPH This detecting instrument Super Sensitive No. 40 of marvelous sen- Receivers to be used In sitivity can be used for detecting secret con- connection with Detect. versations. Outfit consists of Sensitive grph Transmitter.. Transmitter, 25 -ft. Black Cord, 00 50 Receiver, Headband, Case and Battery. $18 $10 Complete rt as ta DETECTAGRAPH JUNIOR DEAF -PHONE The outfit consists of a Super -Sensitive Transmitter, with a cord connector; Super - Detectagraph Rheostat, eBBosomault Sensitive Ear Piece with small black cord; especially made for am- CO -, 25 Church plifying circuit.... ' St., N. Y. C. Black Single Headband ; Black Case and two small Batteries. Transmitter 2h inches in Complete 00 per your ad in diameter, s- Radio Amateur News, of an inch thick, $ 2 please send me free or- and weighs Order lea than three a00 direct from ad. Or write for culars and full particulars $18 free descriptive circular.ir / - De- ounces. For your .bout your Det, tagraph Complete convenience use the coupon. ces. G. ' NAME BOISSONNAULT COMPANY ADDRESS 25 CHURCH ST. NEW YORK CITY CITY Makers of Super- Senitive Microphone Device, e STATE You benefit by mentioning the "Radio Amateur Neros" when writing to advertisers.

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/ j .* / ' t _ _'-J ì\ , \ a\ ` \ ' \ ~ _ `__ _ ' -.P. [ !hi CONTENTS i 'Dí FOR JANUARY 4It:n I,

PAGE PAGE I I L

Eternal Waves..By H. Gernsback, Editor 333 Our Supplement 354 ICú1 'i11' d?1lar The Priess Loop Set - Part Il Crystal and Vacuum Tube Detectors By Walter J. Henry 334 By E. M. Sargent 355 VI1jill CCr+i Dr. de on the Radiophone 35G r I New Radio Apparatus 335 Forest t. NS Radio Telephone on MountMo Hoodoo 336 Loop Multiple Aerial Switch \I\I By John G. Merne, I. M. T. 357 6 Static Elimination by Directional Recep- tion 337 II1 Designing an Amateur Transmitting An- \\' \! tenna By E. T. Jones 358 /` Fourth Prize Award- Radio Contest 342 \ , 'd Clearing Traffic by "Sparks" 359 Construction of Simple Radio Telephone lli I By E. S. Rogers 343 A Case of Nerves -By Julian K. Henney 360 Multiple Stagege Amplifiers 5r1 Design of Mil ON By Prof C. L. Fortesque 344 Radio Digest 361 .,_

Rebuilding the station -By P. F. Geagan 346 With the Amateurs 362 q, ¡ÿ3i Squier "Wired Wireless" 348 Club Gossip ,I Elec- A Trigger Relay Utilizing Three Junior Radio Cours' .365 trode Thermionic Vacuum Tubes :vi,nemunun.on.u, By W. H. Eccles and F. W. Jordan 349 New Radio Patents .ì6ö Radio Constructor 350 $100 Radiophone Prize Contest 369

How to Build Arc - Generators By H. W. Secor, Associate I. R. E. 352 I Want to Know 370

W.u` esvv[D1.w%- »-,.ß11tU1V1+aTU.. \ .-Trif/iiiic-..uví/GÌti AMATEUR NEWS Is publish' on the 25th of each month at Included. ALL accepted contribution, are paid for on publication. A RADIO are 12 numbers per year. Subscrip- special paid for novel good accompanying 233 Fulton Street, New York. There rate is aaperlmeats: Photographs to 11.50 a year In U. S. and possessions. Canada and foreign them are highly desirable. tion price coin stamps accepted (no RADIO AMATEUR NEWS. Monthly. Entered its second -clue matter New York. N. Y.. foreign ccoWcoins or stamps). Singlo 15tcentseac8h cpy June 8th. 1919, at the Post Office at under the Act of sent FFrrstieon reaneet. Chedu and money orders should be drawn to March 8. 1897. Title registered U. S. Patent Office. Copyright, 192. by be PUBLISHING CO.. INC. If you Would change E. P. Co.. Inc.. New York. The Loperlmenter Publishing Co.. 233 Fulton order of E7U'cuIMENTER of thin maparine are yourour address otify w ...... promptly in order that copies be not mlecarried or Street. N. Y., N. Y. The Contents copyrighted and No copies sent erplration. must sot be reoreduoad without giving full credit to the publication. and contributions to this Journal should be eddrest RADIO AMATEUR NEWS Is for sale at W oewsetanda in the Cotten All communications 239 States and Canada: also at Brentano's. 97 Avenue de l'Opere, l'aria. S'or cannot be dunessulll postage been Great Britain: GooFry Parker & Gregg, 82 & SA. The Mail. Ealing. London. tiEna ed' pte cobutlonntrtrcú Publisht by EXPERIMENTER PUBLISHING CO., INC. 233 Fulton Street, New York City H. GERNSBACK, President S. GERNSBACK, T R. W. DE MOTT, Secretary

yn .,, ;r. _ . , G -

www.americanradiohistory.com l.nwary, 1920 RADIO AMATEUR NEWS TRIODE TRIODE TRADE MARK) (TRADE MARK) Audio Transformer Type P Vacuum Tube Socket Type F

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Standard Vacuum Tubes $7.00 each. Price $1.25 Postpaid The base of this socket is bakelite dilecto and will not crack and break like the moulded material of the usual socket. Contact springs are stamped with identifying letters. Base is provided with three rubber feet and four countersunk holes for panel mounting. We also manufacture: Due to its operation on the principle of voltage amplification Eaton Oscillators Two Step Amplifiers through resonance this transformer provides a maximum of low frequency amplification and is superior to all others. Grid Leaks Damped and Undamped Receivers Permits reliable daylight reception from European stations FARADON MICA TRANSMITTING CONDENSERS Establishes new amateur long distance records. Renders remarkable amplification of all signals. Standard and Special Radio May be used with the Marconi and all standard tubes. Equipment of Every Description

ENGINEERS, DESIGNERS, MANUFACTURERS Wireless Specialty Apparatus Co., BOSTON, MASS., U. S. A. Vacuum Tubes Repaired We repair the filaments and other elements in all types of vacuum tubes and guarantee them to operate equally as well as a new tube. Inmost cases they operate better. We produce wonderful oscillators, detectors, and amplifiers. MARCONI VT DE FOREST VT MOORHEAD TUBES WESTERN ELECTRIC Repaired at Four Dollars and Fifty Cents each ELECTRON RELAYS OSCILLAUDIONS Repaired at Four Dollars each

All Foreign -made receiving tubes repaired at Six Fifty ami power tubes depending upon size. We have purchased a large quantity of burned out Marconi Vts. and electron relays which we offer for sale at five dollars. Remember these tubes are guaranteed good as new. Dealers write us VACUUM TUBE REPAIR CO. 51 1 Perry Building Oakland, Cal.

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www.americanradiohistory.com 332 RADIO AMATEUR NEWS January, 1920 A WARNING to Manufacturers Importers Dealers Jobbers Agents Amateurs Purchasers Users of Vacuum Tubes The Marconi V. T. Patent is Basic United States Letters Patent to Fleming, No. 803,684, Flewlog Pet. No. 803.684 November 7, 1905, has been held to be valid by Judge De Forest Pst. No 841.387 -879.532 Mayer of the United States District Court for the Southern District of New York, and by the United States Circuit Court of Appeals for the Second Circuit. It is a basic patent and controls broadly all vacuum tubes used as detectors, amplifiers or oscillions in radio work. No one is authorized to make, sell, import or use such tubes for radio purposes, other than the owners of the patent and licensees thereunder. Any others making, selling, importing or using them alone or in combination with other devices, infringe upon the Fleming patent and are liable to a suit for in- junction, damages and profits. And they will be prosecuted. THE AUDIOTRON AND THE LIBERTY VALVE ARE NOT LICENSED UNDER THE FLEMING PATENT The price of the genuine Marconi Do not take chances by making, im- V. T. delivered is $7.00 each. The porting, selling, purchasing or using standardized socket is $1.50 addi- vacuum tubes for radio purposes tional. The standard resistance, com- not licensed under the Fleming patent. By selling, purchasing or using plete, costs $1.00 and is made in licensed tubes for radio purposes the following sizes: i megohm, you secure protection under the 1 megohm, 2 megohms, 4 megohms, Fleming patent and avoid the risk 6 megohms. of litigation for infringement thereof. This warning is given so that the trade and public may know the facts and be governed accordingly. Send all remittances with order to COMMERCIAL DEPARTMENT MARCONI WIRELESS TELEGRAPH CO. OF AMERICA RADIO CORPO RATION OF AMERICA 225 Broadway New York Sole Distributors for De Forest Radio Telephone & Telegraph Co. Retail Once end Exhibition Rooms, 25 Elm St., New York Schofield Bldg., Cleveland, Ohio Insurance Etch. Bldg., San Francisco, Cal. 301 Commercial Banc Annex, New Orleans, La. American Bldg.. Baltimore, Md. 136 Federal St., Boston. Mass. 109 South 2nd St., Philadelphia, Pa.

You benefit by mentioning the "Radi. Amateur News" when writing to advertisers.

www.americanradiohistory.com MINE. I ill .14 WIWI. Vol. 1. JANUARY, 1920 No. 7 eMININNIMMOIMNIII softy*. MUNI WA ETERNAL WAVES WHEN Marconi first started his historic experi- wont to say that you couldn't even think hard near the ments with his spark coil as a transmitter and instruments for fear of disturbing their balance! But per - his coherer as a receiver, it took a surprising haps this was an exaggeration. Few of us ever think amount of energy to cover even small distances. hard! - A specially constructed coil throwing a spark over eight inches long Recently great improvements have been made in mul- and which required half a kilowatt tiple step amplifiers transmitted only over a fraction of a mile and it becomes more and more feas- ible now to weed or filter out extraneous disturbances, so After a while we substituted a carbon detector using that the final bulb will only emit such signals as we actually steel needles as an imperfect contact, in series with a pair want. of telphones as a receiver. We immediately found out that we only required a fraction of the former energy of Once arrived on these premises there will then be no the transmitter, to send a given distance. Then came the trouble to make a 50, or a 100 or even a 1,000 step ampli- electrolytic detector which again increased our receiving fier! Perhaps you laugh at such a suggestion. Ten years range enormously, due to its greater sensitivity. In turn ago you would have laughed at a seventeen step amplifier we had the still more sensitive crystal detectors, which which can pick up buzzer signals 300 miles away! So again increased our receiving radius. Later came the the prediction does not matter much -it will soon be a audion which surpassed anything in sensitivity we knew fact anyway. heretofore, and once more our range was vastly increased. But I didn't start out to tell you about a 1,000 step ani- After that came the two -step amplifier which quadrupled plifier, rather I wanted to make a strictly philosophical ob- the best receiving performance of the single audion we had servation on a rather surprising FACT. known. Finally we see the seventeen -step amplifier, with The question before us is: How for can you detect an which -so we are told -you can hear the spark from a 1 electrical wave. Theoretically there is no limit. In other kilowatt station, at any point of the globe- 12,000 miles to words, as time passes and our detectors become more sen- be exact -which is practically half the circumference of sitive we find that we can reach further and further. We the earth! will all live to see the day when the waves emitted from Indeed during the war the British used a seventeen step a buzzer will be picked up after having traveled around amplifier to listen to buzzer signals used for inter-commu- the globe a distance of 12,000 miles. Undoubtedly they nication between German warships in the North Sea. reach much further but unfortunately our earth will then And the distance was often 300 to 400 miles! Just think have become too small, for the emitted waves certainly of picking up such an infinitesimal amount of energy over travel infinitely further. such a great distance. , It is so small that the little frac- Electromagnetic like tion that impinges upon the receiving is well nigh waves, space are infinite. A radio aerial wave shot out into free incalculable. It would take a long string of zeros to ex- space -just exactly like a light press the value in amperes. ray -will keep on traveling at a speed of 186,000 miles Of course, it goes without per second, for thousands saying that a seventeen step amplifier is a most tempera- of years to come. mental affair and a great deal more "nervous" than the Just as we can pick up light rays from distant worlds proverbial cat! of the Universe, which left there thousands of years ago, A trolley car starting up a mile away will give out and are only now seen by us, so do radio waves travel on shrieks in the horn connected to the seventh bulb. A bell towards distant worlds, to be intercepted there centuries rung in a distant building will produce a Niagara of noise hence. horn. you in the If wave your hands ten feet away from tap the seventeen -stepper the change of capacity of your body This ought to make us careful when and how we will produce a loud noise in the receiver! Our English the key ! ! friends who first perfected the seventeen -stepper were H. GERNSBACK.

TO OUR READERS DUE to the great printer's strike which paralyzed New This, the January issue, should be in your hands on York's entire printing trade, RADIO AMATEUR NEWS January 22nd. The February issue will came out on was printed out of town for several months. This February 11th. March issue on March 6th, April issue greatly delayed us and prevented your magazine from March 29th. reaching you on time. RADIO AMATEUR NEWS is now We desire here to thank our readers for the patience printed in New York once more, and soon will appear they displayed with us, during a very trying period. again on schedule time. T PUBLISHERS. 333

www.americanradiohistory.com 336 RADIO AMATEUR NEWS January, 1920 Radio Telephone on Mount Hood Forest Protective Wireless Telephone at an Elevation of 11,225 Feet By C. M. ALLEN

THE success of a forest fire protec- stance, the umbrella type of antenna was half inch bamboo, in 6 % -ft. lengths, was tive organization, in the work of fire very strongly recommended. This would used in the construction of the long mast. prevention, is determined to a large have required a :umber of captive balloons Each piece was reinforced by wrapping extent by the efficiency of its system anchored around the top of the mountain 19 wire of wire bands of No. spring brass about telephone lines. While these for holding the outside ends 1 lines of the wires, % -in. wide between joints. The lengths give excellent service, they fail oc- and as the supply of balloons was limited, of bamboo -eight in number -were joined casionally on account of physical condi- it was not attempted. There was also a by fitting oak pieces inside of the ends; tions which cannot be controlled. The pos- wide range between suggestions made in and the mast was held rigid by four a -in. sibility of using the wireless telegraph to regard to the construction of the counter- special steel airplane cordage truss guys, supplement the wire telephone line under poise which would have to be used, as an from top to bottom, these being spread these conditions about 36 in. at has been consid- the center by ered, but the in. oak spreader complicated na- arms. The use ture of the ap- of the oak pins paratus, in the for spreader p a s t, together arms was a mis- with the knowl- take, as the first edge of the code sleet storm coat- required for its ed them to a operation, eortt- thickness of bine to make its about 3 in. which use impractical. snapped two of However, radio them off and al- apparatus, par- lowed the mast ticularly t h e to crumple up. wireless tele- One - half inch phone, has been iron pipe was very much im- substituted for proved and sim- the oak pins and plified during the proved very past year; and satisfactory. A the United States 4 - wire antenna Forest Service, was used at first, recognizing the each wire being need of an aux- a No. 10 strand- iliary to the wire ed copper wire line system of 250 feet long, communication, with a spread of is now carrying 3% feet be- on a series of Left -Wireless Telephone Aerial at the Government Camp Hotel Mt. Hood. Upper Center tween wires. As -One of the Wireless Telephone Outfits Set Up for Experimenting in the Basement of Mr. tests with the Allen's Residence. Lower Center -Pack Horses Were Used in Transporting the Radiophone it was impossi- wireless tele- Sets Across Four Mlles of Snow Covered Fields. Right -Great Difficulty Was Experienced ble, due to gla- phone for the In Erecting a Mast on the Mountain Top. The Lookout House Stands at an Elevavtlon of cier ice, to make purpose of de- 11,225 Feet. an ordinary termining to earth ground, a what extent it may be used. While these earth ground was out of the question on counterpoise was used with fair results. tests are not yet completed, the results the summit. Operation of the sets was started about have been so satisfactory that it is believed However, it must be understood that August 1st. The best results in the tests a very optimistic view of the future pos- these differences of opinion were not due which were made during the remainder of sibilities is justified. There are, of course, to an insufficient knowledge of the under- the month were obtained with the use of limiting conditions regulating wireless tele- lying principles of radio work, but to a a two -wire inverted L type antenna, 30 phone transmission, but the work so far lack of knowledge of physical conditions, feet high, with a spread of about 10 feet this year has demonstrated that the ap- and it was decided that in this case, as it between the wires. There was practically paratus in its present stage of development will undoubtedly be in other cases, the only no difference in the results obtained with can be set up and operated successfully by thing to do was to get results -if impos- the use of either an insulated counter- Forest officers under extreme conditions. sible with one type of antenna or counterpoise composed of two insulated copper Two wireless telephone sets were loaned poise, to be prepared to try another. Con- wires laid on the ground under the two to the Forest Service by the War Depart- sequently more material was packed to the antenna wires, or a counterpoise made of ment, and permission for their operation top of the mountain than would be needed two strips of 12 in. chicken wire netting. in making certain tests was granted by the for a permanent station, but much valuable In both cases about six- tenths ampere Navy Department about July 1, last year. information was obtained. The transpor- radiation was obtained. They are vacuum tube sets known as the tation was by auto truck from Portland, In telephone conversations between the "S. C. R. 67 ", for use on the ground by the Oregon, to Government Camp (which was two sets the voice carried very clearly Signal Corps for airplane communication used as a base), a distance of about 57 and was about as loud as over the wire and are purposely designed for a limited miles; from there by pack horse to the lines; telegraph signals from many stations workipg range of about 12 miles. foot of Crater Rock, a distance of about over the continent were picked up. They For the preliminary tests it was decided eight miles, four of which are across the came in particularly strong on top of the to locate one of the sets at the lookout snow fields; and from there packed by mountain, in some cases loud enough to station on Mt. Hood which has an elevation Forest officers about 1,000 feet up to the be heard all over the cabin. Static, or of 11,225 feet, with the view to making it summit of the mountain. electric interference, in regard to which a permanent station, and the other set at After making a careful examination of there had been so much speculation, and Government Camp, which has an elevation the conditions on top of the mountain, it which at times was very annoying on the of 4,000 feet and is some eight miles from was decided to erect an inverted L shaped wire line to the summit, was almost entire- the top of the mountain. antenna 250 feet long, supported at one ly absent in the wireless receiver. Very little data were available for use end by a- 50 -ft. mast erected by the side The energy for operating each set was in designing the station on top of the of the lookout cabin, and the other end furnished by two 5 -cell Edison storage bat- mountain. There was a wide variance be- attached thru strain insulators to wires ex- teries. About 8 amperes, at 13 to 15 volts, tween the suggestions from radio engineers, tending some 50 feet farther southwest to or about 110 watts, which is a fraction over many of which were impracticable on ac- a short mast set in a point of rock sticking one -tenth of a horse -power, is the amount count of physical conditions. For in- up beyond the small glacier. Two and a (Continued on page 383)

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 337 Static Elimination By Directional Reception By GREENLEAF W. PICKARD

N the early days of radio communica- for condensation; A droplet, perhaps con- these clouds being eventually drawn out tion, those disturbances which have been sisting of iron or calcium, will grow around into streaks or lines roughly parallel with variously called "static," "atmospherics," this nucleus until it attains a diameter or the lines of force in the earth's magnetic "X's" and "strays" were either attributed the order of a wave -length of visible light. field. This is exactly what we would ex- to distant lightning, or more vaguely At this point in its growth, the pressure pect of a charged particle in rapid motion, and correctly to "atmospheric when it encountered a magnetic electricity." 'While it is still true held. It would tend to spiral its that our knowledge of static way down a magnetic line of causes is far from satisfactory, force, at least until it reached we have at least progressed- to and penetrated the upper level of the point where the distant the atmosphere, whereupon it thundershower has ceased to be would begin to spend its energy considered an important source in ionization, with light as one of static, and are now able to of the less objectionable by- concentrate our attention on the products. higher levels of the atmosphere. The writer is well aware that Such disturbances as may exist a theory is at the most tentative, at these levels are unquestionably and under suspicion of unsound- electrical, so far as they concern ness, until it yields confident our receiving circuits, and are forecasts. Until such time as it due to a supply of electricity may have been proven by this which in some way is generated acid test, it is unwise to over- in or supplied to the atmosphere. burden a theory by speculative The normal electrification of our exterpolation. However, even at atmosphere, observed as a rather this risk, as well as the graver marked potential gradient in the one of diversion from the sub- lower and more accessible layers, ject matter of this paper, the accompanied by downward elec- writer cannot refrain from a trical currents and attended speculation as to the possible from time to time by high level connection of the auroral struc- auroral displays and magnetic ture, above outlined, with certain storms, is undoubtedly due to facts as to the difference between ultra- terrestrial sources. Ac- east -and -west, and north -and- cording to Arrhenius, the sun is south radio communication. If, the ultimate cause of electrical as would certainly appear from phenomena in our atmosphere, the visible aurora, east -and -west and altho his original theory has bound waves encountered a suffered certain modifications celestial hurdle, while north -and- and additions in the past fifteen south waves ran peacefully be- years, it will well serve as an tween the ionized filaments, the introduction to this paper. ease of north -and -south, and the The sun being an intensely comparative difficulty of east - heated body, must in consequence and -west radio communication have emitted electrons in such would be readily explained. One abundance as to have acquired a might go a step further, and at- very large positive charge. This tribute, at least at times, a suffi- charge, estimated by Arrhenius Fig. 5-This Type of Coll Aerial Was Demons ra ed By the Write at Dorchester, Mass., in 1907. Note How It Con orms to the Loop ciently periodic spacing to these as three billion volts, forms a Aerial So Much In Vogue at the Present Time. Ionized clouds for the formation powerful center of attraction for of a gigantic reflection grating, stray electrons and negative ions, which of light upon its surface considerably ex- and thereby account for de Forest's obser- are gathered in even from space far be- ceeds the solar gravitational pull upon its vation of the easy transmission of cer- yond the confines of the solar system. mass, and the droplet moves away from the tain wave -lengths, and the high absorption An electron or a negative ion, moving in sun. Such of these minute particles as of others. Certainly the visible aurora fre- toward the sun under this force, will may reach the vicinity of the earth fall quently has a very regular spacing, and it eventually reach the outer and cooler solar into our upper atmosphere, and as they might be intesting to ascertain if it be of atmosphere, where it will form a nucleus carry with them their original electrical the right order to account for these effects. charges they constitute an important source But for the purposes of thi, paper it of electricity. There are, however, two other sources, also solar, but differing materially in their mechanism. One of these is the ionization produced by the shorter wave -lengths of the sun's light, as it impinges upon the gas atoms in the upper strata. The other consists of a direct emission of either electrons (Beta rays) or, according to Chapman', charged helium atoms (Alpha rays). This direct emission apparently does no take place all over the suds surface, but jets out in streams, pre- sumably most vigorously from sunspot areas, in consequence of the great thermal gradients and magnetic forces existing at such spots. When such a stream, which may be ten or more degrees wide, sweeps across the earth, it makes itself evident as magnetic storms and intense aurora. The aurora, or Northern Lights, give us a certain illumination as to the manner in which these charged particles arrive and move in the upper levels of our atmosphere. Perhaps the most striking part of this phenomena is the streaky or discontinuous structure of most aurora. It would appear Flg. 3. -The Pre - Dleckman Shielded An- Is a Complete Solution of the Hissing as if, instead of a steady shower of tenna Fl.. A -Another Type of ore - Dleckman Cage Variety of Static. charged particles, they arrived in clouds. Antenna, Patented by the Writer In 1907.

www.americanradiohistory.com 338 RADIO AMATEUR NEWS January, 1920

I. 111.fi1 IITCITL9 M.5.100% G. Ir. LILUII charges in the upper atmosphere, the con- n.^CLLM tUneIlI.tITIOI dition of affairs with respect to the receiving station might be pictured somewhat as in Fig. 1. Here a discharge stratum, H -H, forms a portion of a sphere concentric with the earth's surface E -E. This stratum is not only above the receiving point R, but Fig. 1. -A Discharge Stratum As It Appears envelops this point in all directions, even Forming a Portion of a Sphere Concentric to the horizon. It is at once apparent that with the Earth's Surface. individual discharges, as at a; b and c, will set up waves or pulses which will arrive at the receiving station with intensities inversely proportional to their distances a -R, b -R and c -R. This may be approximately expressed by saying that the intensities will vary as the sine of the vertical angle, save near the horizon. To exactly state the law would obviously require a knowledge of the height of the stratum H -H which we do not yet possess. How- ever, it is apparent that the intensity on the horizon, as at d, is far from being zero, and is most probably between five and ten per cent. of the zenith intensity. The maximum static intensity, tho by no means confined to the zenith, is evidently distinctly above the receiving point R. At first thought it would seem that the total amount of disturbance produced by static would be represented by the product of the individual intensity by the frequency. Inasmuch as EARTH avo..4,6*Witte r' the number of individual discharges in- FIg. 6.-Two Separate Collectors Are Em- 0., cluded in a given small solid angle near ployed Spaced a Material Fraction of a Afp the zenith, as at e, is much smaller than Wave Length. Flg. 2-Copy of the Cage Antenna Patent the number included in the same solid angle Showing the Method of Connecting the taken nearer the horizon, as at f, varying same amount of energy in a given time, a Antenna and the Shields. in fact approximately as the square of the bell will give the greatest response when cosine will be sufficient to assume only that the of the vertical angle, it would seem the taps are individually strong and fairly charged particles enter out atmosphere in that the total effect should increase as we well separated in time, rather than when pass from the a discontinuous manner. Charged clouds zenith to the horizon. In the taps are weak but frequent. Further- general, the will be formed at some high level, prob- writer finds this to be the fact, more, at least until such time as all recep- altho ably drawn out so that their greatest length it not infrequently happens, particu- tion is photographic, the psychology of the lies approximately north -and -south, and in larly in the forenoon, that light static comes receiving operator must be borne in mind. down above, a manner similar to that a from with very little from the There is doubtless an illy defined, but none observed in horizon. thunderstorm, there will be equalizing dis- This may be explained by con- the less existent frequency of maximum charges first, sidering such horizontal static as con- disturbance. For example, the writer finds between these clouds. At be- sisting cause of the low dielectric strength of the of weak discharges at great distances irregularly spaced disturbances most atmosphere at the higher levels, such dis- from the receiver, and of so great fre- troublesome when their mean frequency is charges will occur at small potential dif- quency (because of the summation of so about twice that of the signal element. many individual discharges) as ferences, and hence will tend to be of small to blend If the discharging clouds are drawn out individual intensity but frequent occur- into a distinctly "soft" disturbance. Bear- in a north -and -south direction, we should of in rence. As the charges sink toward the ing mind that static acts upon a receiv- expect that the waves arising from such earth they will reach denser air, and there ing circuit by pure impact, a not inapt discharges would show a certain uniformity the discharges will become of greater in- analogy is that of a bell, set into vibration in their planes of polarization. Altho it dividual intensity but less frequent. by irregularly spaced impacts. For the would be absurd to think of the discharging clouds as accurately oriented linear oscilla- We recognize today two important, that tors, nevertheless there should be a certain is to say bothersome, varieties of static. preponderance in that direction. One of these is the "click," consisting of 6 71100 B".u./". It eft. 1 110.E The writer's theory of might .t,.u.01 Y.0,un0`4` static be rather widely separated but very strong .. MUM" SPACE summed up as follows: According to the disturbances, reminiscent of the discharges assumed character and location of the dis- that aptly named apparatus, the of static charging masses, static waves may be ex -, machine. The other is the "grinder," - petted to come in on the receiving stations which runs the gamut of noise from a from all angles in altitude and azimuth, with grating or grinding sound thru something a maximum individual intensity from above, resembling handfuls of gravel thrown and a maximum frequency in the neigh- against a window, with perhaps slushy or borhood of the horizon. The r total dis- even hissing sounds at the other end of turbing effect will in general come in from the scale. The clicks are most probably points nearer the horizon than the zenith, relatively low level discharges. This is r altho the altitude of the ring of maximum supported by the fact that local thunder- disturbance is indefinite, The individual storms give rise to clicks which can some- .r planes of polarization may take all possible times be identified with visible discharges angles, but with a preponderance in a between cloud and cloud, or cloud and r direction determined by the earth's mag- ground. Grinders, however, would seem e netic field. Finally it would seem that the to have two possible origins. In the first most probable static wave form was a single place, they might arise from very high highly damped pulse, because of the low level discharges of considerable tho irregu- conductivity of the discharging masses. lar frequency. The writer has succeeded According to the above theory, the prob- in imitating, with a disconcerting fidelity, lem of the elimination of static and the grinding static by the simple process of dis- preservation of the signal consists simply charging a small condenser thru a series of the reception of a wave -train originat- circuit of a wet string and a vacuum tube, ing at a definite point, and the exclusion replenishing the condenser from an in- of static pulses originating at all points fluence machine. Grinding static might in altitude and azimuth. In a broad sense, also arise from the summation of many dis- there are two solutions for this problem, tant clicks. There is some experimental one involving a separation of signal and evidence of the existence of these two va- W.,Ticsoes, IrIJctlrart. static based upon their a---. difference in wave rieties, either singly or mixed, and to this ta. i_.e 5iy.3. _AA.. Q24 .e CWx., form, and the other a separation based a later reference will be made. For the simply on sharply directional reception. It present, our principal interest is in the is quite clear that if we could restrict recep- in the static waves arrive a manner which Fig. 7. tion to small solid angle including the we assume -A Method of Obtaining Sharp Dl- at the receiving station. If a rectlonal Reception Invented by J. S. Stone distant station, there would be relatively more or less uniform distribution of dis- in 1902. little static included. To use an optical

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS 339 analogy, the problem is essentially like,that ionable O. W. rICt1 ;. of late to attirbute this invention of receiving monochromatic light signals to MM. Bellini and Tosi, it should tru oar I. .m tin/. be noted in full daylight. A spectroscope or a filter .950,186. ivro.tyssóuie that these gentlemen first published an ac- screen would be one solution, and directive count of their work on November 14, reception as by a telescope another, but best 1907,.. The writer began his development of all would be a combination of the two. of the coil or loop aerial in 1902, and pub- In present day radio communication we lished an account of his work on June 15, have already highly developed the spec- 1907,., almost exactly five months prior to troscopic or filter separation of signal from MM. Bellini and Tosi. It is of interest static, as 'by sharply resonant circuits and in this connection to note that the writer, beat reception. But aitho we have had two on September 13, 1907, demonstrated one practicable types of sharply directional re- of his coil aerials at Dorchester, Mass., to ceiving circuits for the past twelve years Lieut.-Commander S. S. Robison, detailed or more, very little use of these appears by the U. S. Navy for this purpose. This to have been made until quite recently. particular coil aerial is shown in Fig. 5, In a paper, entitled "Absorption and Re- and consisted of two turns of wire forming flection of Electrical Waves," read before a square about nine meters on a side. Altho the New England Wireless Society on De- but two turns are shown, from one to ten cember 7, 1912, the writer, after discussing turns were actually employed, depending the probable relation between ionization of course, upon the wave -length. Ex- conditions in the upper atmosphere and ceedingly accurate bearings of a number electrical wave transmission, went into some of distant stations were taken, some over detail of his early experiments to deter- sixty kilometers away from the loop, with mine the nature of static. At his first ex- a maximum error not greater than 2 de- perimental station, at Blue Hill Observa- grees of arc. tory, Milton, Mass.,. he conducted a long Further on in the 1912 paper, the writer series of tests which apparently showed a said: relation between the wind velocity and the "But the worst summer static appears to number of disturbances in a given time, be at a very considerable distance from the which led to the conclusion that effect was receiver, and I believe it originates at some a local one, possibly consisting of an actual of the higher levels already discussed in discharge to the receiving aerial from elec- this paper; probably many miles over our /h{ heads. I trified masses of air moving past the an- also believe that static is simply tenna wire. This theory was rudely upset ---`iL gay a discharge from one high level cloud of by his further work in 1901, when com- Fig 8.-System Devised by the Writer in ions to another similar cloud, very like parison of tapes at Galilee and BrieIle, N. 1905, In Which Two Aerials Are Tuned to what we see from cloud to cloud in a the J., about twenty miles apart, showed the Distant Transmitter. thunder shower ; that is, an equalizing dis- same dots and dashes from static day after charge. Like lightning, static appears to day. It was clear from this that some as against the most bothersome varieties be non -oscillatory, as may be readily found static, at least, came from discharges at of static, it seems only fair that he, and by experiment." not Dieckmann, should receive whatever The writer does not claim novelty for C credit is due for this invention. While the the "static from above" theory. In fact, shielded antenna is open to attack from Airy. said in 1911: clicks and grinders, it is a complete solution It was concluded that most of the dis- of the hissing variety of static, due to a turbances were not due to local weather direct dischange to the aerial. Where a series condenser is employed in the antenna c circuit, this is very apt to charge up to the limit of its dielectric strength, and then spill over, giving an excellent imitation of pistol shot static. This occurs most markedly during snow storms, and on shipboard, where the aerial is slung immediately over the funnels, the vessel manufactures this type of static in abundance, and delivers it effectively to the waiting antenna. Shield- ing is of distinct value in such cases. Continuing his paper before the New England Wireless Society, the writer then describes his early work with directive D o aerials, particularly with the ungrounded Fig. BA.- Showing the Receptive Curve of coil or loop aerial. Again, as with the Fig. 10. -A Cosine Curve of a Vertical Loop the Combination of Two Loop Aerials. Dieckmann cage, the writer must pause to Drawn in Polar Co- Ordinates. correct a heresy. Altho it has been fash- considerable distances from the receiving conditions, but to discharges taking; place aerial. He then said: in the upper atmosphere, and at very great "A little later, I surrounded a receiving distances from both stations. He thought aerial by a Faraday cage. constructed with it would be eventually proved that these loading inductances to avoid shielding the atmospherics were connected with magne- aerial inside from the desired signal. This tic disturbances, and that they had the same seemed to eliminate a small portion of the common origin -i. e., the arrival of nega- static- probably that portion due to direct tively charged electrons from the outer discharge to the wire from the atmosphere space into the earth's atmosphere." -but had no observable effect upon the dis- The writer concluded his 1912 paper with tant variety." the following up-to -date treatment of the At this point, the writer wishes to call static problem : attention to the careless manner in which "I believe. as a result of considerable members of this Institute refer to the Fara- experimental work, that the real solution day cage antenna shield as a "Dieckmann of the static problem lies in the use of Cage." Dieckmann, in 1912., first published sharply directional recdving antenna. Pro- his description of an aperiodic shield or vided only that the static does not origi- cage around an aerial, so designed as to nate at the same point as the signal, good permit the passage of signal waves, but to directional reception should eliminate most be opake to static pulses. The writer has of it." published, in a patent. filed six years before As already stated, there are two practical Dieckmann's date, this exact thing. Ref- methods of obtaining sharply directional erence to Fig. 2 will show the antenna reception. In the first method, originally wires A, A, surrounded by a cage, sectioned suggested by Elihu Thompson. in 1899, off into short elements which are connected patented in England by S. G. Brown in the together by impedances and grounded thru same year., more fully disclosed and pa- other impedances so that an aperiodic shield tented in this country by Stone in 1902,.. results. While he is inclined to agree with elaborately worked out for two, three and Weal/anti. that the device is of small utility Fig. 9. -The First Portable Radio Compass four collecting circuits by Braun in 1906,,.

www.americanradiohistory.com 340 RADIO AMATEUR NEWS January, 1920

lar direction is cancelled out in the secon- N dary, and does not affect the detector. A further advantage of this system, which has recently been pointed out by Weagantu is the fact that it has materially greater or sharper directional reception than any single type of collector. This is obvious when we consider the fact that the loop aerials M, and M. have simple cosine reception curves in the horizontal plane, and that a pair of open or non-directive aerials, separated as W are M, and M. in Fig. 8, by a considerable fraction of a wave -length, with currents combined in a common secondary, have also a cosine curve characteristic. The combination of two loop aerials in the manner shown in Fig. 8 has therefore a cosine square reception curve. The second method of directional reception, devised by the writers, does not in- N volve, even for long wave reception, such S 11. -When the Vertical leap Is In the geographical dimensions as Fig. 13. -This Figure Represents a Plan of the systems the Hemisphere Vertical Plane the Reception Curve Is In shown in Fig. 8. This second method con- Over the Loop. the Form or a Circle. sists simply of a closed tuned circuit or coil aerial, of dimensions small as compared nate from under foot, and hence is shown and more recently used by Weagant.,, two with a wave -length. In its most effective in dotted line. or more separate collectors are employed, form, consisting of a coil aerial combined If, however, a loop is placed aloft, as in spaced apart a material fraction of a wave- with a so- called "open" aerial, this method aircraft work, the useful reception curve length in the line of propagation, as shown gives true unilateral reception. The coil in this vertical plane is a full circle. Finally, in Fig. 6. These collectors act upon a corn - may be of quite small dimensions, par- the complete three -dimensional reception mon secondary circuit in such wise that ticularly when it is employed simply as a surface of the loop is a torus. This torus when the collectors are simultaneously af- radio compass. In Fig. 9 is shown the first is shown in Fig. 12, and differs from the fected by any disturbance, the currents set portable radio compass, which was em- conventional anchor ring or doughnut in up therein will arrive in phase at the center ployed by the writer in 1907 -1908 for map- that it has no hole in the center, this pe- of the system, and there, by opposed wind- culiarity making its representation some- ings, be placed 180° apart in phase in their what difficult. The significance of this last effect upon the secondary. Because of this figure is obvious-the loop receives more opposition, such currents will not affect the or less from all points in space, excepting detector, and no signal will be produced. only along a line passing normally thru its On the other hand, the signal wave, passing center. The further meaning of this figure the collectors successively, will set up cur- is that maximum reception occurs only in rents therein which will arrive at the center all directions in the plane including the loop, of the system in an out -of -phase relation, and the significance of this fact is perhaps and such signal currents will add in their best brought out by Fig. 13. This figure effect upon the secondary and affect the de- represents a plan of the hemisphere over tector. This is very well shown in Fig. the loop, just as if one were looking up at 7, and clearly explained in the specification the zenith, and the shading indicates the of the Stone patent of which Fig. 7 is the amount of reception from different points drawing. The writer, in 1905, devised a in this hemisphere by a loop placed in an system in which two aerials, tuned to the east-and -west vertical plane. The zone of Fig. 14.- Showing the Complete Reception distant station and separated on centers by in Any Vertical Plane Passing Thru the maximum reception is a belt passing across some thousands of meters, were connected Antenna. the sky from east to west, reception de- to a common secondary by way of phase creasing to zero on the horizon at points adjusting means, so that the currents were north and south of the loop. added in the secondary in such phase as to ping out the wave -front around a transmit- A so- called open antenna consisting of a produce the maximum signal. This method ting station, This radio compass consisted vertical wire, short as compared with a was first published in a patent filed in of a three -turn loop, one meter in diameter, wave -length, has in the horizontal plane a 1907,, and is shown in Fig. 8. The par- shunted by a variable air condenser and a simple circle diagram, that is, it receives ticular case discussed in this publication crystal detector. equally well from all points on its horizon. involved two large loop or coil aerials, ar- Heretofore, the reception characteristics In any vertical plane passing through the ranged in an east -and -west plane for the of aerials have been studied principally, if antenna a quite different reception curve purpose of transatlantic reception. These not exclusively, in the horizontal plane. The results, as reception is a maximum on the loop aerials consisted of long, low rec- writer is not aware of any publication deal- horizon, and decreases to zero at the zenith. tangles, and were tuned to the desired ing with the three -dimensional character- The complete reception in any vertical plane wave -length by inserted series capacity and istics of aerials, although for quite some passing through the antenna is shown in inductance. With this system, it is possible time past points of wave origin other than Fig. 14, and is, of course, the familiar to so adjust the phase relations of the cur- the horizon have been common, e. g., static, cosine curve. That portion below the hori- rents arriving at the secondary that inter- and more recently transmitters on aircraft. zon is shown dotted in 'the figure; if the ference or static arriving from any particu- Just why radio engineers have elected to open antenna consisted of an ungrounded live in a two -dimensional world is rather z puzzling, and if this paper has no other effect than to add another dimension to N their life, the writer will feel fully repaid for his labor. In Fig. 10 is shown the now familier reception curve of a vertical loop or coil antenna in the horizontal plane, consisting of a cosine curve drawn in polar co -ordinates. This is an ideal curve; actually a coil aerial gives a more or less distorted figure-of- eight, sometimes tending to an W hour -glass shape, and usually more or less unsystematical. The reasons for this distortion have only recently been worked out in detail, and some of the more important causes of distortion will be explained later in this paper. In a vertical plane including the plane of the loop itself, reception is obviously symmetrical, and the reception curve in this N plane is a circle, as shown in Fig. 11. If the loop is near the ground, the lower half the Loop Re- Fig. 15. -Here the Reception Belt Rings the Fig. 12. -This Signifies That of the reception curve is normally without ceives More or Less from All Pointe In Space Horizon and Reception Is Zero from the Excepting Along a Line Thru Its Center. interest, because signals do not often origi- Zenith.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 311

/,.In,111. PATENTED SAIL 0 e. IIKADD. fl, IIOI .bination of loop and open reception cannot IITLLYOCICt IITCCCOYYOI.CATIOR 11 eWogA0ICCIC et COMPONENTS be attributed to MM.. Bellini and Tosi, rrrrr 'often as this has been attempted of late. .5- In this figure is shown the coupling of a loop and an open antenna to a common secondary, by way of phase adjusting means, so that the currents in the loop and the open antenna, normally 90° out of phase, are added in phase in the secondary circuit. If now, as by suitable dimensions of the loop or by coupling adjustment, or by both, the currents from the open antenna are made equal, in their effect upon ./7 the secondary, to those from the loop, the result of this addition, in a reception curve on the horizontal plane, is shown in Fig. a. 17. Reception is at a maximum from the Fig. 17. -Here the Reception Is at a Maxi- mum from the Direction O -A, and Is Zero direction O -A, is zero from the direction from O -B. O-B, and has intermediate values from other directions, the complete curve being a z cardoid. Such a circuit, employed as a direction finder, gives the true bearing of the distant station, and does not, as with the simple loop, leave the direction inde- terminate by 180 °. In a vertical plane including the loop the reception curve is also a cardoid, as shown in Fig. 18, with a maximum on the horizon at A, and zero on the horizon at B. Reception from the zenith, that is, along the line O -Z, being limited to the loop, has half the value of reception along the line O-A. In a vertical plane at right angles with the loop, that is to say, at right angles to the plane of Fig. 18, the Fig. 16. -A Method of Combining Loop Re- reception N Open Antenna Reception. curve is that shown in Fig. 19. ception with Fig. 18. -In a Vertical Plane including the /3 Loop the Reception Curve Is Also a Cardold. linear oscillator considerably removed from the earth, the lower portion of the curve of static reduction. As the effect of static would interest us. Actually, just as with on a receiving circuit is practically pure the loop or coil aerial, and for similar rea- 2 impact excitation, complex waves will be sel sons, this ideal curve usually suffers con- up in the two coupled circuits -the loop and siderable distortion, partly because actual the open antenna -with the result that the vertical aerials have an appreciable hori- just shown ideal diagrams of reception zontal length in most cases, and partly be- curves and surfaces are but roughly ap- cause of unsymmetrical or electrically A proximated. These diagrams are, of course. warped surroundings. The complete three - only true for undamped wave reception, or dimensional reception surface of the open for static reception on substantially aperio- antenna is therefore just like Fig. 12 laid dic circuits. down flat, or, more exactly, laid down flat Shortly after America entered the war. and half embedded in the ground, if the the Wireless Specialty Apparatus Company open antenna is on the earth's surface. It equipped a radio station for Mr. Alessandro will be seen from this that the loop and Fabri, at Otter Cliffs, near Bar Harbor, the open antenna have identical reception Me. When the station was completed, Mr. surfaces, but in planes 90° apart. Similarly Fabri donated it to the Navy, and it was to the loop, Fig. 15 shows a plan of the first used as a low power spark station. hemisphere over an open antenna. In this However, it was very shortly found that the figure, the reception belt rings the horizon, location was an excellent one for trans- and reception is zero from the zenith. If atlantic reception, and this eventually be- static came solely from above, an open an- Loop Cos4Sin/3 came its principal service, the station tenna would make an ideal eliminator. Open - Si. gCoe/3 finally becoming the premier reception point Equally, if static came in on the receiving in this country. The summer of 1917 hav- point with the same intensity from all points Loop +Open - Cos «Sinf3 +SintlCos/3 ing shown that altho the Otter Cliffs sta- in altitude and azimuth it would be difficult tion had excellent signals, it also had over- to account for the well -known freedom of Fig. 19. -This Is the Familiar Cosine Curve Again Tilted Thru 45' with the Vertical O.Z. whelming static on occasion, Mr. Fabri the loop from static.). But if we assume invited the writer to install directional re- that in general static is at its worst near This is the familiar cosine ceiving circuits for static elimination adapt- the horizon rather than the zenith, a com- curve again, tilted thru 45° with the vertical O -Z. ed to the requirements of transatlantic serv- of Figs. 13 and 15 will show a rea- The parison complete three -dimensional reception sur- ice. Within a few days after this request, the son for the relative immunity of the loop. circuit shown in Fig. 11 was face is difficult to show in a two -dimensional installed, com- In Fig. 16 is shown the method referred figure, or even to describe accurately in bining open antenna reception with loop or to above, which combines open antenna coil reception. This was immediately found loop or coil reception. A words. It is a distorted apple- shaped fig- reception with ure, with the at the stern successful in improving the signal- static the date of this drawing -June origin pit, and the glance at vector of maximum reception at the other ratio, and was at once placed in service. 10, 1907 make it obvious that the cotn- The loop A consisted of a solenoidal coil -will end. Some idea of this surface may be No. 16 B. S. obtained from Fig. 20, which gives its sec- of four turns of & (1.3 mm. 2 tions in three perpendicular planes, passing (Continued on page 3721 thru the origin O at the front of the figure. A Altho it is not an exact figure of revolution, inasmuch as the principal distortion is at the front of the figure, it will suffice for our immediate purposes to consider that it is essentially a cardoid of revolution. 'yM Al From a consideration of the three - r lJ--J2ò5 dimensional unilateral reception of the cir- c L, cuit shown in Fig. 16, it will appear that static originating at points other than on s the horizon in the direction of the distant transmitter will either be weakly received, I I or, if it happens to originate on the horizon 0 at a point 180° from the transmitter, it will not be received at all. The circuit Fla. 20. -This Figure Has the Origin at the Fig. 41.- Solid, Uninterrupted Copying Dur- Stem Pit, and the Vector of Maximum Re shown in this figure is not at present, how- ing Periods of Severe Static Was Made Pos. caption at the Other End. ever, the best arrangement for this method sible with This Circuit.

www.americanradiohistory.com 342 RADIO AMATEUR NEWS Awards of $100 Radio Prize Contest 3rd Prize Winner $25.00 in Gold AN IDEAL RECEIVING SET By URBAN D. WORNER

THE set to be discussed, is of the The detector is of the DeForest old tu- The coil L in the diagram is 32 in. cabinet type as shown in the photo- bular type audion, and gives very gratifying long and 3% in. in diameter, a tap being graph. The cabinet itself is made results, both on arc and spark stations. Its taken off every 2 inches and is shunted by of mahogany wood and is 20 in. long, oscillating qualities being marvelous. The the variable condenser & (Murdock) hav- 11 in. wide, and 11 in. high. The detector can plainly be seen in the centre ing a capacity of .001 mfd. It is necessary base is 12 in. longer than the cabinet in of the front panel of the cabinet. to have a condenser of rather large ca- order to accommo- pacity here, so by date the secondary, filling C' with a which rides upon good grade of paraf- the two brass rods i s oil its capacity fastened to the up- is raised to .005 right piece of wood mfd. which is suit- near the end of the able for all pur- base. poses. By means of The terminals of L and C' signals are the individual in- greatly amplified; struments are this is more pro- brought out to bind- nounced on long ing posts on the than on short back panel. In this waves.

way it ' is an easy The plate circuit matter to change is brought into ad- to any desired justment by means hook-up, without of the high voltage undue trouble or "B" battery, which any unnecessary consists of eight wiring. No 710 "Bveready" All the instru- flashlight cells which ments, except the are sealed in wax. loading inductances, The voltage is reg- the coil L, and the ulated by both taps variable condenser and a high resist- C. are mounted in ance carbon rheo- the cabinet. The stat. T h e reason primary P of the for this double ad- receiving trans- justment of the "B" former is 10 in. battery is because in long, 6''/s in. in this circuit it is diameter, and is necessary to have wound with No. 24 the voltage at a critical in S. C. C. magnet point or- wire, being varied der to get the best by the usual units Here Is a Neat. Com pact and EHlelent Receiving Station. Note the Cabinet DesIgn -the results. T h e va- and tens system. Tuner and Audlon Control Are All Contained In the Same Unit. riable C' is o f The secondary S, the Murdock con- which can be seen in the photograph, is The filament F is lighted by a 6 volt 80 struction and has a capacity of .001 10 in. long and 5''/z in. in diameter, being A. H. storage battery, the current being mfd. and is widely used to vary the tone wound with No. 28 S. C. C. magnet wire, regulated by the 10 ohm rheostat shown of the incoming signals. Brandes 2800 and is varied by means of a sixteen point on the extreme lower left hand corner of ohm phones are used, which give excellent switch, the connections being brought di- the panel. The filament current is cut on results. The wave -length of the primary rect from the secondary to the binding switch to the and secondary circuits is increased by or off by the small next means of the two large loading coils. These posts on the base. The secondary S, is rheostat. shunted by a Murdock variable condenser coils are used only for arc stations having C' which has 23 plates and a maximum ca- The grid condenser C' should have a very long waves. The coils are identical pacity of .0005 mfd. capacity not exceeding .0001 mfd., and is in size, being 42 in. long, 4 in. in diameter usually of the variable type; but I have and wound with No. 22 S. C. C. magnet The hook -up used in the secondary dr- in. cuit is the well -known Armstrong circuit found that equal results can be obtained wire. A tap is brought out every 4'/, by using a very small fixed condenser, con- My aerial is of the inverted L" type, employing a second air coil adjustable ft. transformer M, which has the following sisting of two brass plates separated by has four No. 14 copper wires, spaced 3 65 ft. long, 55 high at one end, dimensions: P' is 4 in. long and 4 in. in mica. apart, ft. and divided into and SO ft. at the other. The lead -in is diameter eleven sections: the lower end and is com- S' is 4 in. long and 3% in. in diameter, taken from posed of four No. 14 copper wires, bunched divided into fifteen sections. Both P' and into the station, all S' are wound with No. 30 S. C. C. magnet just before coming wire, the sections being brought out to taps connections being well soldered. the upper left -hand side of the front The ground is connected to the city water on pipes and to a series of 10 ft. pipes driven panel. Connections between P' and S' are the in the diagram. coup- down in moist earth. The lead -in from clearly shown The ground to the station is composed of two ling between P' and S is adjusted by ribbon are means of a coupling device which projects in. copper wires which side just brought in directly to the aerial switch. through the of the cabinet, back My aerial is rather small to do very much of the filament rheostat. It is absolutely coupling between long distance work, nevertheless surprising necessary to have the P' results are obtained, from both arc and and S' adjustable, as through the mutual us- is forced spark stations. NBA, Darien, Panama, inductance of M, energy back ing an arc set can be copied at all hours from the wing circuit to the grid circuit, of the day or night, the signals being which results in the amplification of sig.: strong. NAA also can be heard both dur- nals when the coupling is properly ad- ing the day and night; by adjusting M, the justed. It is not necessary to have P' and coil L, and the condenser C', NAA's spark S' divided into sections, but for very close signals can be amplified to such an extent running it is desirable. Wiring Diagram of Urban Worner's Prize Set (Continued on Page 384)

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 343 Construction of a Simple Radio Telephone By E. S. ROGERS

THE accompanying photograph shows the radiophone set which the writer built, and which has proved very satisfactory in every respect. In the following article only the constructional details and a few points on the operation of the set will be described. As seen in the photo, the set is mounted on a piece of marble 18" x 24 ". The Mar- coni bulbs are observed mounted at the top of the panel. 'The microphone shown is one of the Stromberg Carlson long distance transmitters. In the center can be seen the voltmeter which reads up to 600 volts. At the bottom of the panel is shown the milli- ammeter which is connected in series with the plate circuit, while on the right side are the switches and controls for the inductance mounted on the back. The rheostat for regulating the filament current is mounted on the left. The inductance used in the set consists of two coils L1 and L2 and L2 is made to telescope inside of LI. The coil Ll is 4%" in dia. and is wound for distance of 4". 12 is 4" in dia. and is also wound for 4 ". Both coils are wound with No. 16 D. C. C. magnet wire. The filter system used, consists of two choke coils. connected in each line from the generator and shunted by two condensers of 2 mfd. capacity as shown in the diagram. A choke IA is also connected in series with the grid of the modulator valve. The inductance 1.3, is of one to two micro- henrys. A small glow lamp is connected in series with the aerial lead. All connections should be made with heavy insulated wire and all the joints well soldered. The wires from the different circuits should be kept as far away from each other as possible. The bulbs used by the author were the Marconi V. T., Class II, as already. stated. It was found that some of the harder" tubes would oscillate on voltage as high as 500 V, but that the average would work on not more than 350 V. The motor generator used, is after all not such an expensive article as most amateurs think. A good second -hand outfit which was purchased for this set did not cost over $50.00. In tuning the set, make the milli -ammeter and aerial glow lamps show the greatest readings for max. radiation. It is a very simple matter to see if the set is oscillating. By cutting off the switch connecting the Here Is a Simple Design of Radio Telephone. With This Set Mr. Rogers, a Canadian Amateur, grid to 12, the milli- ammeter will drop off is Having Remarkable Success, Not Only in Voice Transmission But Also In Phonograph in value, if the set has been oscillating Concerts. properly. When the V. Ts. are working two -bulb oscillator and one -bulb modulator. NEW WIRELESS TELEPHONE at full output the plates get very warm, By using the whole five bulbs as oscilla- STATION. often getting cherry red in color. tors, powerful signals can be produced for The voice and phonograph music have telegraphy. As a matter of fact, one sta- As the North Jersey coast was selected been transmitted all over town, and even tion situated in west end of the city, has as the field for the establishment of the received with galena receiving sets. This heard the signals on his one -bulb oscillator first of the great transatlantic wireless tele- has also been accomplished by using only a receiver, all over the top floor of the house. graph systems, so has it been chosen as the proper location for experimental purposes in connection with the inauguration of wireless telephone service between Eur- ope and America. Operations have for some time been under way on the Foxhurst farm west of Elberon on the construction of one of four wireless telephone stations along the Atlantic seaboard thru which it is hoped to make possible the carrying of the voice from one continent to the other with the same facility as now marks the sending of messages thru the ether from points hundreds and thousands of miles distant. All the vast resources of the Western Electric Company are behind this particular wireless telephone project. Three big towers, rising more than 160 feet into the air, already have been placed, The Circuit Used Is Simple and Any Amateur Should Have Little Difficulty in Constructing and the complex system of ground wires Set. laid.

www.americanradiohistory.com 344 RADIO AMATEUR NEWS January, 1920 The Design of Multiple Stage Amplifiers By PROF. C. L. FORTESCUE. M.I.E.E. simplest THE amplifying circuit is cies) and the resistance Ra may be re- inductances that shown and capacities, oscillations will in Fig. 1. Here A, G, and placed by a condenser and inductance in be set up and maintained. F are the valve electrodes, If there are no the anode, parallel as in Fig. 2, the circuit inductances or capacities, grid and filament respectively. The being ac- the voltages and curately tuned to the frequency of the currents will steadily change in one direc- . filament temperature is maintained tion or the other by current from the variations of grid potential. until the altered slope of battery B, and con- the characteristic curves trolled by the adjustable resistance To stops the action. R.. A a sustained oscillation this circuit On the other hand, the steady potential is maintained between coupling between the behaves in the same way as the resistance the ends of the system may anode and filament by the battery B. the tend to oppose circuit of Fig. 1. But to an oscillation of the changes at the input end. More power varying amplitude thé behavior is quite is required then from the external source different. For example, during the first to maintain the changes in the input dr- few cycles after the oscillation is applied cuit, and the effective amplification is re- to the circuit the current flowing round duced. Obviously. the greater the opposi- the circuit La Ca has not been built up to its normal value and the effective amplification is less than is the case at the later stages. With a circuit such as that of Fig. 2 the tuning of the condenser Ca becomes more and more critical as the resistance Ra decreases. The more critical the tuning the less will be the relative amplification at Fig. t Shows the Simplest Form of Amplify frequencies other than the frequency to ing Circuit. Fig 2 -An Inductance and Ca which the circuit is tuned. An efficient cir- oacity Used in the Plate Circuit. cuit consequently leads to a selective amplifier. The effective damping of the cir- Two Valves In Cascade, Using In anode current passing cuit can be regarded as being made up of Resistances thru the anode Place of Transformers, In the Plate Circuit. resistance Ra. The small potential varia- two parts, viz. (a) the resistance of the tions to be magnified are superimposed circuit itself ; and (b) the equivalent re- tion coupling, the poorer will be the am- upon upon the steady voltage maintained by sistance due to the resistance of the tube plification obtained. the battery B' between the negativ! terminal in parallel with the circuit. This latter In an arrangement giving a high amplifi- of the filament and the grid. These varia- component decreases with a decrease in the cation ratio (say 1,000 to 1 on the voltage, tions may be looked upon as being pro- ratio of La /Ca and vice versa. With large i. e., 10' to 1 on power) the transfer back values duced by a tiny alternator D, representing of La /Ca it constitutes the prin- of a very small proportion of the power . the input circuit. Under these conditions cipal cause of the damping and may render from the output end to the input end will the potential variations consist of a rise the circuit almost aperiodic. Thus a cir- be sufficient to render the circuits unstable, above and fall below the mean potential cuit having a very high ratio of La/Ca can- or to reduce the amplification very con- of the grid relative to the negative end of not be efficient, and is the reverse of a siderably. selective the filament. The changes of the grid amplifier. It is thus a matter of the very greatest potential are immediately followed by In practice, where high selectivity is es- importance to secure an adequate control changes of the anode current which in turn sential and tuning is not objected to, the of the coupling between the low-power and are accompanied by changes of the anode efficient circuits may be used. But where high power ends of the instrument. This voltage due to the change of potential dif- approximately equal amplification is re- coupling may be capacity coupling or a ference across the resistance Ra. quired over a wide range of frequencies, mutual inductive coupling, or a combina- The curves of Fig. 3 show these varia- then a high ratio of La /Ca and a valve of tion of the two. Resistance coupling may tions and their relative phases, it being low effective anode resistance would be also be employed in conjunction with either assumed that the variations of potential used. capacity or inductive coupling. Capacity applied to the grid are more or less sinu- Multiple -stage amplification can be ob- coupling is always present to some extent. soidal in form and of constant amplitude. tained with either of the arrangements of At high frequencies it is always important The and is generally relative values of the alternating com- Figs. 1 or 2, the anode -circuit voltage vari- the controlling factor. If ponent of the voltage across Ra and the ations of each valve being applied to the inductive coupling is also used, the condi- alternating grid voltage give the voltage grid of the valve next in the series, and tion actually arrived at is a balance between step -up of the valve and circuit. so on. Fig. 4 shows a possible arrange- the two. With this arrangement of pure resist- ment of two valves in cascade, using re- Fig. 8 shows a method of using a ca- ances thruout the variation of the volt- sistances in the anode circuit. Separate pacity coupling, and Fig. 9 a combination age across Ra can be made an exact repro- filament and anode batteries are required of inductve and capacity coupling. Both duction of the variations of the grid volt- with this arrangement. In Fig. 5, however, these systems are applicable to more than age, provided that both are small compared almost the same results are obtained with- two valves, but the connections for the ca- with the range of voltage corresponding to out this disadvantage. A similar arrange- pacity coupling must necessarily be made the active portions of the characteristics. ment for two valves with tuned anode cir- to the right valves or opposition effects For low- frequency changes the conditions cuits is shown in Fig. 6. will be obtained. of the previous paragraph can be realized A cascade arrangement of valves with In practice it is desirable that the action without difficulty. But capacity effects are step -up transformers between the valves is of the amplifier should not depend upon serious at high frequencies (radio frequen- another possible combination and is shown a very critical adjustment of this coupling. in Fig. 7. When allowance is made for the Consequently the unavoidable coupling self- capacity of the windings this circuit is very closely allied to that of Fig. 6. The action of any amplifying system, electrical, mechanical or otherwise, is strongly Affected by any transfer of energy back from the output end of the system to the input end. With the amplifiers now under discussion, the transfer back of energy may be caused by any form of coupling between the output and input circuits. If this coupling is such that the changes at the input end are accentuated, it follows that changes of a given amplitude in the input circuit can be maintained by a smaller external power supply. In the extreme case the coupling may be strong Here the Same High Potential Batteries and enough to do more than maintain the Filament Batteries Are Used for Both Variations and Relative Phases of the Gr d changes at the input end. The system is Valves. The Results Obtained Are the Same Voltage Plate Current, and Plate Voltage. then unstable, and if the circuits consist of as With the Circuit in FIg. 4.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 345 must be reduced as far as possible. For amplitude to be maintained in the input changes which are to be dealt with in am- high -frequency working,. of the un- circuit for a smaller power supply from plifiers are small compared with the volt- avoidable sources of this coupling is the the external source. This is in itself age range of the active portions of the equivalent to amplification. Under perfect conditions, with the reaction under perfect control, it would be possible to secure anything up to an infinite amplification by slowly increasing the power supplied back to the input circuit from the output circuit until the power required from the external source becomes vanishingly small. In practice, however, there are limitations. The control soon becomes very critical and the adjustment so delicate that the least change in the conditions in the valves upsets it. Also, unless all the valves are working on points on their characteristics where the amplification is a maximum, any An Amplifying Circuit Using Tuned Plate Here a Step -Up Transformer is Used Be Circuits. momentary large disturbance will slightly tween Stages. increase the effective amplification and capacity between the grids and the anodes cause the self -maintained oscillations to characteristics. So long as this is the case of the valves themselves. set in. Thus amplification by "reaction the characteristics may be regarded as A common method of designing an am- which in reality is merely using the ampli- straight lines and the changes of current plifier is to adjust it so that when the fier to neutralize the resistance of the in- calculated from the observed slopes of the mean potential difference between the grid put circuit, must be reduced to a very characteristic curves. and filament has a particular value there moderate amount. The modern tendency This procedure involves a fundamental is good amplification with a definite tend- is rather in the direction of avoiding it assumption, viz., that the ordinary static ency towards the unstable condition. If an altogether if possible, the extra amplifica- characteristic is followed even at high fre- adjustment of the grid- filament P.D. is now tion required being obtained by using more quencies and with minute amplitudes. It is provided, this tendency can be decreased valves in cascade. difficult to see wiry the static and dynamic or increased by making the mean grid -fila- In the second place, where continuous characteristics should not be the same. The ment P.D. more positive or more negative. waves are being received by the heterodyne fact remains, however, that it never seems When more positive, the grid damping is method, the use of a separate set of instru- possible to secure the amplification per increased, which increases the effective re- ments to generate the beating oscillation is valve that is indicated by numerical calcu- sistance of the circuits in which the oscil- avoided if the amplifier can be so con- lations from the static characteristics. lations are produced. Usually, also, the trolled as to generate these oscillations it- With high -power transmitting valves a total amplification is somewhat reduced. self and yet maintain its power of amplifi- difference between the static and dynamic Both these effects tend towards stability. cation. Many amplifiers have been de- characteristics is fairly definitely estab- signed which serve the double function fairly well, but generally there is considerable loss of amplification and simplicity of operation. The loss of amplification arises from the fact that, once the beating oscillation is started in the input circuit, it immediately builds up to a value which is large compared with the incoming oscillation to be amplified. By the time that this large oscillation has been amplified by the whole series of valves, the voltage amplitude is such that for the last valves the grid voltage is coursing to and fro far beyond the limits of the slope of the anode - current characteristics. This difficulty is leading under modern conditions to the use of separate low -power generating sets for Capacity Coupling Is Used Between These the beating oscillations. A Combination of Inductive and Capacity Two Stages. producing Couplings. Small irregularities in the action of the If the grid is made mode negative the con- valves are due to two causes, viz. (a) the lished and appears to be due to surface and the tendency to electron emission from the filaments is ap- changes of the filament. Whether some ditions are reversed -power oscillate is accentuated. parently not perfectly uniform; and (b) similar effect takes place in the low There are two quite distinct ways in thé amount and nature of the residual gas amplifying valves is a question that re- which reaction can be employed. In the is not constant. quires much further investigation. first place, as has already been pointed out. Anything of the nature of imperfect con- Paper read before the Wireless Section the tendency to produce self- maintained tacts must be scrupulously avoided. of the Institution of Electrical Engineers, oscillations enables currents of a given In general, the current and voltage London, England. (Abstracted.) A ROYAL AMATEUR

you did not can be effected without the PERHAPS use- of a large aerial, al- it, but King Al- known though t h e transmitting phonso is much inter- as the ac- stations are very far dis- ested in radio tant. company ing photograph shows. In his earlier days King the recent opening of Alphonso was considered a At great sportsman and he was the National Engineering the King of keen on all scientific exper- Exhibition iments. At present consid- Spain evinced great inter- appara- erable interest in r a d i o est in the wireless prevails amongst royalty tus, which permitted him to be- and nobility in Europe, not listen to communication only in the commercial ra- on between the ing carried dio but also the amateur station of Nauen and one photo- side of it as well. It is in America. Our said that many of the shows His majesty graph higher minds are w e l l listening in on the special designed that along on the road to the apparatus, so realm of radio bugs. reception and interception

www.americanradiohistory.com 346 RADIO AMATEUR NEWS January, 1920 Rebuilding the Station By P. F. GEAGAN

NOW that amateur stations are again advantage to know the natural wave length, allowed Since the average antenna at amateur to operate there is a the capacity, and the inductance of the stations great deal of activity is of short wave length, it will be in the line of antenna. The wave meter is used to obtain necessary to have placing in commission stations our number one coil of these values, but it is, in most cases. too small value. It should that have been inactive since the expensive be wound in the a piece of apparatus for the ex- pancake form and preferably with outbreak of the war and the closing of all perimenter to enjoy. It is possible how- Litz wire, it should also be wound upon a form ever to improvise one which will give these values approximately. Variable air con- 400 densers are obtainable at moderate cost, and one of these used with several coils 1111 !í of wire of known value of inductance and a small low voltage lamp, such as is used 1111111111111111011111111111 in pocket flashlights, will measure wave length, capacity, and inductance over a con- 11!".i siderable range. The condenser 11pni11 should be calibrated for ni 111111 capacity, that is, a curve sheet should be !í 11 furnished with it, showing the variation in 1111 capacity from zero to one hundred and 111111 o eighty degrees of the scale. I believe there o 1111111111 11 M b éo 10 roO KO MO VO b are condensers to be M b !O b VO Po MO XO MO bought which furnish Degrees on condenser Degroes on Condenser sew/e such a curve with st04 riq. the condenser, but if one Ply.! t cannot be located, a curve If You Know Maximum may be drawn With Thls the Capacity of Your that will be Curve the Wavelength May Be Condenser This Curve Will Enable You to fairly accurate, provided the Read Directly from the Cond Scale. Calibrate the Condenser. maximum capacity of the condenser is known. and held rigid so that the This is marked by the maker in most turns may not stations by the government. Much advance change position and so vary the inductance has been made in radio communication dur- cases and Fig. 1 shows a curve which would value in handling. be fairly accurate ing the time that the operation of private for a condenser having Some radio clubs own collectively a capacity at full scale, at one hundred a wave stations has been forbidden, and the owners and meter, and in such cases the value eighty degrees, of .002 mfd. is of the of such stations have read a great deal in It neces- coil may be obtained by comparison with the magazines and periodicals devoted sary only to lay off at the bottom of a sheet to of the wave meter in the following manner. radio in regards to, and in explanation of, co- ordinate paper the condenser scale If any oscillating circuit degrees from zero to one hundred be used to excite the many improvements. Naturally all ex- and the wave meter and a reading eighty in equal divisions, in like manner obtained, we perimenters have been impatiently waiting may then substitute our condenser, coil, and for the time when the ban would be lifted, mark the left hand side of the sheet in lamp, connected micro- farads, starting in series, for the wave and they would again be able to try for with zero at the bot- meter and find the resonance point tom, and marking divisions equally on the themselves new appliances and circuits upward. condenser scale. This will be when the about which they have been reading. It is desirable to so divide the number of lamp glows divisions with greatest brilliancy. It is In consequence as to bring the maximum or full desirable to make the there is at present much scale capacity figure near coupling between the digging up of apparatus long lain idle and the top of the two circuits only strong enough to make the sheet, so as to make the curve long feverish activity in preparation to get back and lamp glow a dull red at resonance, as easier to read. also reduces this into the fascinating game. It the error enables a closer reading to be and to listen and the liability of mistake taken than once more to familiar, in reading to if lighted brilliantly. Let us assume faraway sparks. a minimum. that Perhaps without Because of the capacity be- such an exciting circuit measures exception all have made tween the plate two hun- mental reservation when planning edges it is not possible to dred and fifty meters on the wave this re- obtain zero- capacity, meter, setting up of their station, that and so we must start and our improvised meter indicates reson- it would the curve some be an improvement over from point above zero. ance at thirty-six degrees on the condenser. the old one in This capacity between plate many ways, and the purpose of this article edges is very By referring to our condenser capacity small however and so we may adopt is to describe a few simple methods which a point curve, Fig. 1, we find that the capacity of a few divisions above zero to represent it. the condenser at this will enable one to know approximately the The point is .00047 mfd., values capacity at full scale or one hundred or 423 cm. of wave length, inductance, and ca- and Using the formula pacity he is eighty degrees, we mark at the point using, without having to make X ,, in where the line marked one hundred and -2*VCL all centimeters, (cm.), a greater outlay of money than perhaps eighty Then 25000=6.2832V423L can be spared. and the line marked .002 intersect and draw a straight line from this point to 25000' Of course without knowing the quanti- the one marked on the left -hand edge above ties one is handling, getting efficient or = 423L work zero. The capacity of the condenser at any 6.2832 v out of a mixed lot of apparatus is largely point on the scale then is read at the left - a hit or miss proposition, and it has often hand side of the sheet where the line from / 25000 ' happened that the amateur has faithfully that point, and the line from scale division on 1 =423L a 6.2832 followed method of connection for which which we desire to read cross on the di- / much is claimed in a magazine without agonal or curve line. 25000 achieving the looked for results, due to the or Thus, referring to Fig. 1, fact that the values used, unknown to him, the capacity at (6.2832 /1 were entirely out forty degrees would be .00051 mfd., and of proportion. It is of at one =L hundred and twenty -seven degrees 423 would be .001444 mfd. In fixing the zero capacity point consideration 4ntenno must be given to the design of the condenser. If it be built up of a comparatively large number of plates of relatively small area, the hey edge capacity would obviously be greater than if built of half as many plates of twice the area. Due to the arbitrary method of fixing the zero point there will be a slight error at the lower portion of the curve, Irons! this disappears, however, as we go up the or coi/ curve provided the maker's rating mark is Ground correct. The inductance coils are not so easy of Pig 3 rig. 4 calibration, and while there are a number } of formulae available for calculating the Fig. 3- Method of Connecting an Improvised inductance, they are more or less compli- Wavemete r. cated and present a liability of error. Flg. 5-A Condenser Should Be Used Across It the Gap If the Spark is Not Sharp and White. Flg. 4- Exciting the Antenna by Means of a is much better to rely upon comparison or Spark Coll. Fig. 6 -Here a Condenser Is Inserted In the measurement to get these values. Ground Lead.

www.americanradiohistory.com It January, 1920 RADIO AMATEUR NEWS 347

This worked out gives a value of 37429 phones across the condenser. The circuit is 20000=2+r V 414L cm. or 37.429 M.H. inductance, the value then set at approximately six hundred 20000 of the coil. The other larger coils may be meters, and after we have read our con- in like manner and a wave or = v 414L worked out denser value from the capacity curve we 6.2832 length curve plotted for each. can extract the inductance value of the coil To construct this wave length curve, proceeding as with the wave meter com- / 20000 ' after having obtained the inductance values parison. This method will not be as ac- or( 1 =414L of our coils, and using the same formula curate as the other, due to the detector \6.2832/ and telephones across the condenser, unless as above, X = 2v V CL, we figure the wave length at, let us say, two points on the the detector and telephones be used to indi- or( condenser scale, twenty and one hundred cate resonance when measuring wave 6.2832 and fifty degrees. Referring again to our length instead of the lamp. =L condenser curve, Fig. I, we find the capacity We see in the question column of the 414 radio magazines a great many requests for the wave lengths of various antenna, and Key with such an arrangement as described here this measurement is easily obtained. It is only necessary to excite the antenna as in Fig. 4, couple our meter to it, and Ca/ measure by reference to the wave length curve for the particular coil used. Any small spark coil may be used to excite the antenna, and as steady a spark as possible should be maintained while taking the measurement, for the reason that if the Burztt spark be ragged and broken, a fluctuating reading results which is difficult to read. If exciting from a transformer of con- fi(y. Q siderable power an arc is apt to form at re ,. M s n o r .o _,w, m muff A. w re the spark gap and this is to be avoided, the "g e Fig. 7 -An Inductance Used In the Ground spark should be sharp and white, not soft, Resonance Curve of the Transmitter. Lead. red and wavy. If trouble is experienced Fig. 8 -Here the Wavemeter Is Used as a in getting a proper spark, a condenser ca- Driving Circuit. pacity placed across the gap, as in Fig. 5, This worked out gives a value of 24472 will remedy the trouble provided the value cm., or 24.472 mh. inductance for our an- of the capacity is not too great or too small. tenna. at twenty and one hundred and fifty de- A condenser capable of withstanding high Once the capacity and inductance of the grees to be .0003 and .00169 mfd., respec- voltage must be used also, or it will break antenna are known it becomes a simple tively, or multiplying by 900,000 to convert down. matter to calculate how much inductane into cm. 270 and 1521 cm. These values will be necessary to add to the antenna multiplied by the inductance in cm. of coil This reading should be taken with all circuit to reach a certain wave length, or number one, the square root of the products turns of the sending helix out of circuit, how much capacity we must insert to re- extracted, and these roots multiplied by the antenna going as direct as possible to duce to a certain wave length. For instance, 2A or 62832, gives us 20000, and 47406 cm., the spark gap, and as direct as possible to using our antenna described above, having or 200 and 474 meters wave length, respec- ground. In most cases it is necessary to a fundamental of two hundred meters and tively. From these values we can now con- wrap the antenna or ground lead around capacity and inductance few in of respectively struct a wave length curve similar to our the wave meter coil a times order .00046 mfd. and 24.472 mh., we wish to condenser capacity curve, plotting condenser to obtain sufficient coupling between the know how much inductance we must add degrees at the bottom of the sheet as be- two circuits ; sufficient insulation to prevent to reach a wave length meter coil must of twenty-five fore, and meters wave length at the left - sparking to the wave be hundred meters. The formula then be- hand side. Marking the points where the provided, however, in order that the meter oscillation be due entirely to resonance and comes X =2+r V .00046 (24,472 + L), or to lines from twenty and one hundred and put the values into cm. fifty degrees intersect the lines from 200. and not forced by direct coupling. 250000= 6.2832 474 meters, we draw a straight line thru V 414 (24472 + L) If it is desired to obtain the antenna or(250000 ' these points from the left -hand margin of capacity or inductance, or both, a second the sheet to the one hundred and eighty l 24472 -1-L reading must be taken after inserting a 6 2832/ degree line. This curve, Fig. II, gives us known value of capacity or inductance in the wave length at any point on the con- the antenna circuit as in Fig. 6 and Fig. 7. 414 denser, reading in the same manner as the This capacity must be constructed so as condenser capacity curve. to withstand the high voltage and of not Two or more additional coils may be too great value. Denoting the first measure- \' wound and calibrated in like manner, ment in meters wave length, or the antenna or I depending on what wave lengths it is de- natural, by X, and the second reading, 6.2832 sired to measure. The coil values should with, let us say, a condenser of .001 mfd. 24472 = L be such that the resultant wave lengths capacity in series in the antenna or ground 414 will overlap, that is, coil number two curve lead, by X2, then the antenna capacity This worked out gives a value of 3799404 should start below five hundred and forty- cm., or 3799 M.H. We find then that it five meters, the limit of coil number one. C = X .001. Let us suppose an antenna will be necessary to add this amount of inductance to the antenna to reach a wave If a wave meter is not at hand for measuring natural comparison, and a coil of known two hundred meters, length of twenty -five hundred meters, and making and with .001 mfd. in measuring 165 inductance cannot be purchased, it is pos- series, if a curve of the inductance coil in use be meters, then by the formula above the plotted, taking several measurements in the sible to obtain an approximate measure- (165)' ment in the following manner: (200)'- same manner as in calibrating the wave antenna capacity C = X.001 meter coil, the inductance for any number The antenna circuit of the receiver should (165)' of turns may be readily ascertained from be tuned closely to some signal of ship or or .00046 mfd. the curve. station of which we know the wave length, and couple it to our improvised wave If an inductance be used the same pro- If desired, the receiver, both primary meter with a crystal detector and telephones cedure is followed, but the formula be- and secondary, may be calibrated and across the condenser as in Fig. III. Most X' marked in wave lengths by using the wave of comes L = X L, where L equals the meter as a driving circuit and sending out ships and stations send on a wave length waves six hundred meters, or very close to it, so it of known length to which the re- will not be difficult to obtain a signal of this antenna inductance in cm., L, the known in- ceiver circuits are tuned. A buzzer is con- X nected wave length on which to work. After tuning ductance inserted in series in cm., the to the wave meter as shown in Fig. the antenna circuit as closely as possible, us- antenna natural wave length in meters, and 8, and the meter set at different wave ing the regular receiver, reduce the coupling X, the wave length with known inductance lengths. With the buzzer in operation the in series. wave meter coil is coupled loosely to the between the primary and secondary coils receiver and to a minimum and open the secondary cir- If either the capacity or inductance be the receiver tuned to the maximum signal strength, each point being cuit, couple the wave meter coil to the found the other may be readily extracted marked antenna circuit inductively making sure from the formula used in plotting the wave as found. that there is no coupling to the secondary length curve X = 2v V CL. In the case Those fortunate enough to possess a cur- circuit. Then without disturbing the above the natural wave length being two rent operated device in the form of a meter antenna circuit adjust the wave meter con- hundred meters or 20000 cm., and the ca- to use instead of the small lamp, may deter- denser to maximum response in the tele- pacity .00046 mfd., or 414 cm., then mine the logarithmic decrement of their

www.americanradiohistory.com 348 RADIO AMATEUR NEWS January, 1920 circuits if so desired. This is a profound M.F. capacity and well -built coils of Litz plot the curve as in Fig. 9, marking degrees mystery to many, but is to be found easily wire in pancake form an approximate value of condenser scale at the bottom of the if a quantitative reading device sufficiently may be struck at .05. It should be borne sheet, and current device scale readings at sensitive is at hand. The method of pro- in mind that this value will vary a good the left -hand side. Marking the points cedure is as follows: The spark should deal depending on the construction and where the lines for each reading intersect be as smooth and regular as is possible to values of the coils and condenser, however, and drawing a line thru all the points we obtain in order to prevent fluctuations of even though the error be large it will be have a graphic representation of the man- the needle. With the wave meter coupled of interest to experimenters to make the ner in which the current rises to maximum loosely to the circuit to be measured find measurements. and falls to minimum at each alternation the point of resonance or wave length, we In tuning up the transmitter it is desirable or reversal of current flow. By setting will denote this by X. Then without chang- to have the proper ratio of transformation the coupling between the open and the ing the setting of the wave meter, move it in the oscillation transformer and not too closed circuit at different degrees of close- into closer coupling until the current read- much or too little of the inductance in the ness and plotting a curve for each setting ing device reads nearly full scale, next loading coils, it being possible to have the we obtain a number of differently formed rotate the meter condenser in the direc- two circuits in resonance and still have resonance curves, provided there is suf- tion of longer wave length until the scale poor efficiency due to an improper ratio in ficient flexibility in our oscillation trans- reading of the current device drops to one - the oscillation transformer. By means of former. A series of such curves show dis- half its highest reading. Read this wave the wave meter each circuit may be meas- tinctly the advantage of keeping the length and denote by X,. Turn condenser ured separately after setting to best radia- logarithmic decrement below a certain back toward low wave length until scale tion in order to ascertain what difference if value. reading of current device rises to maximum any exists in the wave lengths of the two It is desirable to mount the condenser and falls again to one -half maximum, read circuits, and also set at different ratio of and lamp of the wave meter in some sub- this wave length and denote by 1t.. transformation using the same wave length. stantial way, and make provision on the The total decrement then is equal to Many interesting measurements may be coils for connection, binding posts, or X, -X, made with the wave meter. Plotting the something similar. The connecting wires D = 157 X , all three in meters. should be of low resistance, preferably of a resonance curve is one that appeals strongly. To do copper or brass strip, the idea being that Since this represents the decrement of the this the current quantitative reading device is necessary as in meas- once it is calibrated there should be no circuits being measured plus the decrement uring the decrement. change that might produce an error, such of the meter itself, which we will desig- Setting a clear steady spark into operation and coupling the wave as different lengths of leads or positions nate as D,, the decrement of the exciting meter to the circuit close enough to obtain of parts with respect to one another. nearly a full scale deflection at resonance, The time and money spent on such a circuit is equal to D = 1.57 X D,. we take a series of readings starting at device would be considered well spent by X zero on the wave meter condenser the experimenter, and the editors of our scale radio publications would obtain some relief The meter decrement of course will vary and reading the current device, It us say, with different coils and condensers, but from the tedium of answering the mass of every ten or fifteen degrees to one hun- inquiries as to the wave length of different with condensers of approximately .0025 dred and eighty degrees. We may then antennae. Squier "Wired Wireless"

w1 R E D a single wire by w i reless" "HIS MASTER'S persons thousands is a sys- VOICE" of apart, tem of guiding ra- miles by will soon be an- dio currents nounced by Major means of a wire. Gen. George O. The currents trav- Squier, Chief Sig- el thru the a i r nal Officer of the alongside the wire, army. which guides them to their destina- The method tion. The method makes long dis- eliminates o n e t an c e telephone fault of the or- communication dinary radio, virtually limitless. sends t h e Conversations which A Michigan Amateur from Nome to messages broad- Writes Us That He Ar- cast in all direc- Has a Noble Hound Rio, and from tions. Under the That Once Saved His gentina to Alaska Life, Dad Bless Film. will be a matter Squier method the Of Course, He is Terr- wave currents rr -ubiy Attached to of course, provid- stay close to the Said Hound, Even as ed single wires insur- You and I. So Much, are strung be- wire, thus In Fact, That He Has tween the points ing reliability and Equlpt Towser's Dog - secrecy. House With a Radio mentioned. T h e Outfit and a Loud n e w method will T h e principal Talker. And When He save telephone in long Goes for a Cruise on difficulty the Lake. He Calls Up and telegraph distance telephon- Towser Ever So Often. companies la r g e ing'has been that Keeps Him from Get- ting Lonesome, You sums of money, as to carry the di- Knowl Great Stuff, by its use one wire rect current to a We Say will do the work great distance re- now done by ten quires conductors ,,,,,,,,,,, 111,,, 1, 1,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1,,,,,,,,,,,,,,,,,,,,.,,,, or more. so large as to It is expected to be almost impracticable. The new method pulse to further experimentation with the put the new method in practical operation has adapted an alternating current of high new method, with the result that those in- between New York City and Albany in frequency to the use of the telephone thru terested in the work believe they have the near future. adaptation of the instruments used in wire- found a way to eliminate wire congestion Successful tests of the method have been less telegraphy to the purpose. for good and all. On the ordinary tele- made by Government experts recently The high- frequency current travels along phone wire an alternating current is used, along the line of the Harlem Division of the wire, but not in it, passing thru the employing a frequency of from 750 to the New York Central Railroad. The ex- ether as do radio waves, with the differ- 2,500 cycles a second. The Squier method periments are still going on, but the results ence that instead of being diffused it travels increases the frequency and rapidity of the have been so gratifying that General Squier in a path of which the wire serves as a vibrations so that they "step up" to as high will soon make his formal announcement. core. Enthusiastic persons who know of as 500,000 cycles a second, a feat which General Squier's work believe that as many electrical experts had thought impossible. In removing the insulation from Litz wire as fifty messages may be sent along one The perfection of a method of "wired apply a flame at the place to be bared, wire simultaneously. wireless," by means of which at fewest rub lightly with emery paper and finally The congestion of telephone and tele- ten and possibly more conversations may dip it in sulphuric acid. This insures a graph service during the war gave an im- be carried on simultaneously by means of clean surface for soldering.

www.americanradiohistory.com January, I 9 2 0 RADIO AMATEUR NEWS 349 A Trigger Relay Utilizing Three -Electrode Thermionic Vacuum Tubes By W. H. ECCLES, D.Sc. and F. W. JORDAN, B.Sc. IN a well -known method of using a in such a manner that the grid becomes be used for indicating. In order to restore triode* for the amplification of .wire- more negative than before relative to its the initial conditions it is easy to interrupt less signals an inductive coil is placed filament. Consequently the plate current of for an instant the linkage between the tubes, in the filament -to -anode circuit, and the second tube decreases, and the P.D. or to stop the operation of one or both of another coil magnetically coupled with between the terminals of its plat circuit the tubes, as, for instance, by dimming its this is introduced into the filament -to -grid filament. circuit. This "back-coupling," as it is The external stimulus is led into the sometimes conveniently called, if it is ar- o primary P of transformer ranged in the right sense, greatly exalts PS, of which P 5 the secondary is connected to grid Gr. The the magnification produced by the tube in plate circuit of any alternating E.M.F. applied to the grid; this first tube contains the indicating instrument such an for the induced E.M.F. passed back to the I, as ammeter or a moving tongue relay. resistance grid is in correct phase relation to add di- The r, in the plate circuit of the first tube has rectly to the original alternating E.M.F. its terminals connected instead using induc- to the filament and applied there. If, of grid of the second kind, we attempt tube. Similarly, the re- tive retroaction of this sistance r, in the plate resistance then the circuit of the second to use back -coupling, tube has its terminals connected retroactive E.M.F. applied to the grid is to the fila- fiçl ment and the grid of the first tube. The exactly opposite in phase to the original al- plate circuits In Which the Electrlca contain batteries E,, E., and ternating E.M.F., and the amplifying action A New Relay Circuit the grid circuits reduced. Since, however, Condition Continues After the Original Im batteries e,, e,. The fol- of the triode is lowing values are typical, in phase pulse Has Stopped. and show the one triode can produce opposition performance of the relay: in the manner indicated, it is clear that two - E =78 volts. E, =74 volts. or any even number of similar triode -cir- resistance decreases also. This decrease of n=22,000 ohms. r:= 12,000 ohms. cuit's arranged in cascade can produce is the grid circuit P.D. now transferred to e, =31 volts. ei volts. agreement in phase. Hence we conclude in such a manner that it =17.5 of the first tube The that retroactive amplification can be ob- tends to make the grid more positive rela- change in the indication of an ammeter tained by effecting a back -coupling to the tive to the filament. The result of these at I is from 0 =2.5 micro-amperes. first grid from the second, fourth, and so processes is that a positive stimulus from The sensitiveness of ar- the arrangement on, anode circuit of a set of triodes outside given to the grid of the first tube depends on the transformer PS to some coupled cascade. ranged in an ohmically- initiates a chain of changes which results extent. Using a telephone transformer of It is possible to take advantage of the fact finally in the plate current of the first tube the kind made for Army C Mk. III. Ampli- above stated for obtaining various types of attaining the highest value possible under fier with 20 ohms resistance in the primary, purpose continuously- acting relay, but the the E.M.F. of its battery, and the plate and with the primary connected to a Brown of the present communication is to describe current of the second tube falling to its telephone of 60 ohms resistance, the relay what may be called a one -stroke relay lowest possible value. This condition, there- is operated with certainty by snapping a triggering which, when operated by small fore, persists after the disappearance of the the thumb and finger at a distance of electrical impulse, undergoes great changes initial stimulus. In the initial condition, five feet from the telephone. in regard to its electrical equilibrium, and with the two-tube arrangement just de- then remains in the new condition until Fig. 2 shows another mode of inter -con- scribed, the plate current of the first tube nection of two tubes. The stimulus from re -set. that the is made very small, and of second outside is introduced to the grid the first In what follows, the circuit comprising the reception of tube large; after of the tube through a transformer, as before, and the space in the tube between anode and outside stimulus on the grid of the first filament, the external conductors and the the indicating instrument is again placed in tube the final condition is a large plate cur- the plate circuit of the first tube. The two source of E.M.F., will be called the anode tube and a rent in the first small plate cur- plate circuits are in parallel with a circuit, and the current flowing in it the rent in the common second tube. Either the de- battery E, and the connections are such that anode current. The circuit comprising the creases or the increases of plate current can space in the tube between the grid and the the changes of P.D. between the anode and filament, external conductors and a source the filament of the first tube are imposed of E.M.F., will be called the grid circuit, between the filament and grid of the second and the current flowing in it the grid cur- tube, and the changes of P.D. between the rent. anode and filament of the second tube are The operation of the relay is most easily imposed between the filament and grid of explained when two tubes, each with re- the first. In order to help to maintain the sistances and battery in its plate circuit, and grids' advantageous potentials, grid leak with a resistance and battery in its grid resistances are connected as indicated. circuit, are used and interconnected in the The following numerical values are typi- manner shown in Fig. 1. cal dimensions The electrical stimulus frbm outside E which it is desired to detect and magnify =80 volts. r, 100,000 ohms. is applied in the grid circuit in the first =r:= e, =6=40 tube so as to make the grid transiently volts. relative to more positive in potential the The sensitiveness of this relay could be This causes an increase cur- filament. of made greater than that of Fig. 1, when rent in the plate circuit of the first tube, these large resistances are used. and consequently an increase of the P.D. The circuits described here were the sub- between the terminals of its plate circuit ject of a patent, No. 10290/1918, taken out resistance. This increased P.D. is trans by the English Admiralty, and the descrip- ferred to the grid circuit of the second tube Another Circuit In Which the Relay Has to tion is now published by permission. Be Reset In Order to Restore the A new English term for a three electrode Original Paper read before the British Assnnatior,. See. vacuum tube, i.e., audion. Conditions. fion G (Fnnineerunr) Women Radio Operators Get Licenses "There are now thirty licensed women that they are simply providing a little fun eral and at last the manufacturer, who is wireless operators in New York City. They and a profitable pastime for their little 56 years old, came out with the reason why have formed an organization of their own. sons. he spends his leisure moments listening to Some of them are engaged in other occu- "The other day the president of a wire the wireless ticks. pations and have taken up wireless teleg- concern came to me for an amateur li- "In the old days, he told nie, he started raphy as a hobby." cense," said Mr. Krumm. "He wanted to life as a telegraph operator at $30 a week. As a rule the older men who come to set up an outfit at his Riverside Drive home Now he is worth a couple of thousand Chief Radio Inspector Krumm of the Sec- that would cost at least $5,000. At first he times that amount. One of his closest ond District for a license are a bit shy was trying to tell me that he was doing it friends is a Wall Street broker. In the about confessing their weakness for the for his little boy. days gone by the two men worked side by hobby. In many instances they pretend "We got to talking about things in gen- side as telegraph operators."

www.americanradiohistory.com 350 RADIO AMATEUR NEWS January, 1920

A Sensitive Amplifier By RAY T. FOSTER

THE instrument which I am about to piece on the extreme top of the ringer at right angles to the length of three - describe is not very hard to make. movement as shown in Fig. 1. quarters of an inch from one end. The Before you start, look around your small cup taken from the battery should work table and gather together the follow- be soldered to this short piece on ing: One two thousand ohm ringer such as the top side. Now measure it so that is used in telephones (be sure the circuit this cup will come up about level with thru the coils is not broken). One foot of the top ends of the coils on the ringer copper or brass strip; this should be three - movement as shown in the figure, and bend eighths or one -half inch wide and heavy over the other end for a distance of one enough to require pliers to bend to shape. inch. Drill a small hole to take a wood Two steel nuts or several steel washers screw and fasten to the board so that the (see description below). Two small coil cup will come directly under the centér of springs about half an inch long made from the iron strip. Next solder a common No. 30 spring brass wire. A brass cup brass pin to the center of the iron strip. taken from a flash light battery. A piece of The purpose of this pin is to dip into the the thinnest iron or tin strip about six cup to about half its depth. This cup is inches long and about one -quarter of an to be filled with carbon grains until the inch wide. Now get one thumb screw to- grains touch the needle. If you have no gether with a few small wood screws and carbon grains take a piece of carbon and you are ready to begin. a coarse file and file off enough of the car- First take the old ringer and remove the bon to fill the cup. This will work well clapper arrangement, and let it clap around but the grains are to be preferred. against articles on the work bench for pos- Place two binding posts on the other sible future use! Hunt up a piece of wood end of the board. Connect one lead from suitable for a base board and mount said the upright to which the brass cup is al- ringer on it near or about the center, then Showing the Constructional Details of the tached and the other lead from the frame connect the two leads from the coils to Amplifier. Note the Connections In the Base. of the ringer. binding posts near one end. Now take the Take the thin iron strip and the two The operation of this apparatus is as fol- copper strip and cut off about eight inches; small coil springs and proceed as follows : lows: Lead a wire from one side of your bend each end over at right angles for one Solder one of the coil springs to one end detector circuit to the binding post to which inch. In one of these ends drill a hole the of the thin strip and tie a short piece of the ringer coil is wired and another lead size of the aforementioned thumb screw common sewing thread to the other end of from the other side of the detector circuit and thread it. In the exact center drill a the spring. Now solder a small eye to the to the other binding post. See Fig. 2. one- quarter inch hole. Now mount this point of the thumb screw on the upright; (Continued on page 385) take the iron strip with the coil spring attached and tie loose end of the thread in Tick /er this eye. Tie it up short, leaving only about one -quarter of an inch between the spring and the thumb screw. The strip should now be stretched across just above the ends of the magnets. Cut off short enough so that the other coil spring can be soldered to it and still have just room enough left to hook it on a small hook which is to be soldered directly in a line with the thumb screw on the other side. Next take the two steel nuts or the washers, which should fit tightly over the tops of the coil poles, and magnetize them by rubbing them on a permanent magnet. In doing this see that the pole pieces arc turned so that there will be a positive and a Method of Using the Amplifier With a Crys- negative pole at the top. Take the re- This Shows the Amplifier Connected In an tal Detector. mainder of the copper strip and bend over Audlon Circuit. Mounting For Rotary Tuning Coils To evolve an efficient mounting for the The mounting that is presented here con- rotary tuning coils, now so much in vogue, forms to both of these conditions fully. is a thing that every experimenter is up The coil A is composed of a wooden core against at present. To be efficient it must 34 in. thick and 2 in. in diameter. The conform to at least two different things sides are of wood or hard rubber in. besides being srong. thick and of an approximate diameter of 4 First -It must be stable; that is, it must in. which will vary according to the amount be so balanced that it will stay in the posi- of wire on the coil. Old phonograph rection you place it, no matter what its angle ords are suitable for this purpose. On to the vertical, without necessitating any each side of this coil is fastened a piece of undue friction. copper or brass bar 1/16 in. thick, % in. Second -It must be so constructed that wide and from 3% in. to 4 in. long, the the coils can be changed quickly without end of which is bent out at right angles of the bar. The having to change connections, unscrew and Here Is a Method of Mounting Rotary In- in. from the extremity fasten nuts. etc. ductances. distance from the center of the coil to the

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 351 ends should be the same in all the coils by 2 in. in size. Hard rubber may be used. should be soldered to one of the bars B and provision should be made for the (I) 2 small brass bolts with nuts. as at M and flexible terminals N soldered length of the bar accordingly. This is (J) 2 pcs. heavy phosphor- bronze strip, to each spring J. By means of this con- shown as B. in. wide -1% in. long. struction when the coil is inserted in the Next procure the following materials: First bend the phosphor- bronze strips holder the connections are made automati- (C) 1 hard rubber knob, about % in. J to the shape shown in the drawing, then cally. thick-1g in. in diameter. fasten with the bolts I to the bakelite piece A similar clip should be made to fasten (D) 1 brass bolt, % in. in diameter - H as shown after having bored a % in. on the bottom of the cabinet to hold the 134 in. or 2 in. long. hole in the piece of bakelite. Then after stationary coil when three coils are used (E) 1 brass pillar, % in. high with a boring a % in. hole in the panel K which to tune with. 34 in. threaded hole thru it. is represented as being % in. thick, assem- This mounting should attract the atten- (F) 2 brass washers, % in. or 34 in. ble the various parts as shown fully in the tion of those "bugs" who are looking for in diameter -g in. hole. drawing. A pointer L can be added as de- a serviceable and efficient mounting for (G) 2 brass V in. nuts. sired. their tuning coils. (H) 1 pc. bakelite, 3 in. thick -1% in. Each of the ends of the wire on the coil Contributed by EUGENE M. RIEL. A Variable Condenser In the experiments which the radio of the plates, and the skill required in the is desired, it may be used in connection amateur is performing to -day, the varia- general construction. Some time ago the with a fixt capacity. ble condenser is an important piece of ap- author was confronted with the same prob- Fig. 1 shows the method of construction paratus, and several are required in nearly lem and no doubt his solution will be of and further details are unnecessary. interest. The capacity of a condenser depends upon three factors: The area of the conducting surfaces, the distance between them and the nature of the dielectric. Now, in order to adjust the capacity, it is necessary to make at least one of the above factors variable. In order to change the area of the conducting surfaces, it is necessary to construct a condenser of the "moving plate type" or the "tubular type." This construction is rather difficult, and the average experimenter lacks the proper tool equipment to do a good job. For obvious reasons we will not consider changing the nature of the dielectric. Therefore, we have one possible solution to our problem, and is Details of the Upper Plate and Knob. Is Varied that to change the capacity of the The Capacity of This Condenser by Distance condenser varying the distance between Fig. 2 is Thru Increasing or Decreasing the the plates. another possible construction of Between the Plates by Turning the Knob. the moving plate. This raises the adjust- It is possible with a condenser of this ment knob above the plates and eliminates every hook-up. Reliable variable conden- type to obtain a variable capacity large the capacity effect due to the presence of sers are rather expensive and therefore enough for practical purposes, and also the operator's body. An extension rod many experimenters have attempted to con- one of very delicate adjustment. The di- may also be fastened on the bakelite knob struct their own. The construction is a electric is air, and if calibrated, the con- for this purpose. difficult task, however, on account of the denser will give very accurate results for Contributed by great accuracy necessary in the alignment measuring purposes. If a larger capacity Ii. L. BEEDENBENDER. Lightning Switch Control The location of the lightning switch on A large rectangular loop should first be The above described control. though sim- the outside of the building is a source of made at A so that there will be sufficient ple and inexpensive in construction, has much inconvenience to the amateur, espe- play between the rod and the switch handle. proved to be very efficient in operation. during the This is cially winter. necessary and important, for it by The accompanying drawing illustrates a compensates for inaccuracies in locating Contributed simple device by which the switch may be the bearings and allows the switch to work FRANCIS S. WILLIA \I'. thrown from the inside. In Fig. 1 the smoothly in spite of them. The bends at switch is fastened to the window sill and K and L should be made, preferably with a 5/16 in. hole is drilled through the sash the aid of a vise and hammer. The rod at D, which should be, as nearly as possi- is then placed through the holes at D and N and the bend made at M. This bend will of course have to be made by hand, using heavy pliers. rwilrn The switch now operates by turning the rod to the right or left. It is well to wind the end of the switch íuNIIN handle with tape, as the rod otherwise rubs the paint from the handle. This also im- proves the insulation between the rod and the switch. The insulation value might be further increased by winding the loop A of the rod with rubber and friction tapes; by slipping on a piece of soft rubber tub- Y ing, et cetera. TO sel fig. t In case it is not desired to place the switch as shown in Fig. 1, it may be fas- Control of the Li ghng SwSill.itch Mounted on tened on brackets on the the Wtiindow side of the building as in Fig. 2. When this arrangement ble opposite to the center bearing of the is used, the rod passes directly thru the switch. The bearing 13 is made from a wall. If the interior is plastered, a block block of wood, nailed or screwed to the must be put up to serve as a bearing. It sill so that the hole N is in alignment with might perhaps be better to mount the This Shows the Switch Mounted on a Bracket the one at D. The iron rod C is about switch in an inverted position on the brack- on the Side of the Building and Controlled 5/16 in. in diameter. ets to give it more protection from storms. by the Handle C on the Inside.

www.americanradiohistory.com 352 RADIO AMATEUR NEWS January, 1920 How to Build Arc Generators Ry H. WINFIELD SECOR. Associate I. R. E.

Id K

------FEED SCREW 10 -32 --

TO-POLE. J

H --'SPRING*16 WIRE e-72, -THUMB NUT F- -___ASBESTOS GASKET LANGE STD. ZIRON PIPE GAS JACKET-

- --SOLID CARBON ROD e WATER CHAMBER GAS RELEASE VALVE COPPER ELECTRODE --T----GAT INLET TO+ POLE PIPE ASBESTOS COPPER SLATE STRIP WATER WATER INLET OUTLET

GO BRASS ruer PrOR CEL AIN KNOB EE Fig. 2 Above -A Working Drawing of a % K.W. Arc. Fig. 5 Left -Arc of the Magnetic Blast Type.

t11.1 iiiiiiiiiiii 11.1.41,14. NOW that am;Etlur wireless has form the principal operations for him, the ing features of the design are that it per- come into its own, once more, cost will be small indeed, and will not neces- mits the experimenter to use various gases everyone is interested in construct- sarily exceed the cost of a single vacuum ih the arc chamber; different forms or sizes ing the most efficient transmitting receiving tube, such as the standardized of electrode materials may be used and the apparatus that they can procure type now supplied to radio amateurs. general make -up of the apparatus is simple designs on,- particularly in view of the The first design of radiophone and un- and rugged, thus minimizing the cost of fact that the radio law limits the average dampt radio telegraphy and arc trans- construction and also the cost of operation amateur station to % kilowatt of energy mitter, shown in Figs. 1 and 2, is of a type of the finished arc. input. Also the general trend of amateur designed by the writer several years ago, The principal dimensions of the arc gen- radio development is slowly but firmly and a number of these arc units have been erator parts are given in Fig. 2. Fig 3 gives wending its way in the direction of un- built, both commercially and privately by the outlines of various parts composing the dampt wave transmitters, for both teleg- experimenters, with success. The outstand- arc, and these are made of standard ma- raphy and telephony. terials such as brass, copper, wrought iron, Of course, the usual thing to do is to etc., which the average amateur has about procure vacuum bulbs and endeavor to rig his laboratory or can easily procure at any up wireless "telephone" transmitting sets machine shop or machinery supply house. or undamped wave "telegraphic" transmit- This arc is suitable for a r/a K.W. input ters, by this means. There are two objec- of energy, and may be operated on any po- tions, however, which limit the activities tential from 110 volts direct current up- of the enthusiastic radio amateur when it ward. The higher the voltage used on comes to the vacuum bulb proposition. any of the arc generators, the higher poten- First, the arrangements for use with the tial, of course, of the radio -frequency vacuum bulbs to be employed as generators oscillations delivered to the antenna cir- of radio -frequency energy have to be very cuit. adjusted and official carefully placed and direction, it may be mentioned reports of some of the government depart- In this sources tend to show that that very good results have been obtained ments and other with applied arc voltages of 500 to 1200 the undamped wave telegraphic signals, as from vacuum tube transmitters, volts. Great care must be exercised, radiated voltages above 500 are quite dangerous and are somewhat distorted and not as satis- if come in con- as they might be. liable to prove fatal they factory in all cases, tact with the body, so as to form a circuit Secondly, another stumbling block is the bulbs, even in the smaller thru it. high cost of these ways in which to A number of bulbs would have to be There are two distinct sizes. a gaseous envelope about an arc, connected in parallel or otherwise, to give produce amount of transmitting i. e.,-by dropping alcohol into the arc any appreciable chamber, by means of a graduated oil cup, energy while if a large bulb is desired 2 of money will be needed. the alcohol being vaporized by the heat of very large amount arc. and secondly, very goo en- The present article gives data on small the -a can be used for radio velope for the arc is formed by ordinary arc generators, which illuminating gas such as is used in the telephony or undamped radio telegraphic and if the constructor buys average house for lighting. transmission, Doctor Lee de Forest (who was for sev- carefully and does his own Flg. 1. Showing a Photograph a 34 K.W. his materials of eral years, Radio Engineer for the Ameri- work, or even if he has a machinist per-er- Arc Transmitter -Note the Safety Valve. ,

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 353

can Poulsen arc interests or the Federal Telegraph Co., of San Francisco, Cal) ,.S/otsj2 thick,¢ deep made many important tests with their pow- Sid 2" ; )a32Tap 40 to 50 K.W. f/angesf n 76 fiole ^!* , !Is erful arc generators, rated at Pipe and the long distance transmission of un- lron lu i® 7- damped wave telegraphic signals, and he /032 found that illuminating gas produced very Tap satisfactory results. In this case, about 1,200 L" volts D.C. was used on the arcs. Carbon Holder ;ee B It is of interest to know that at the pres- 3a B ent time, the Federal type of Poulsen arcs k SB have been developed and perfected to such Gas Jacket ¢,fM.US.Thrd.- 2"K- o a degree that they are available in sizes up 3" /0-325a: to 500 K.W. The U. S. Government has To Take ó 0. D. ;B.32 Tap Tofass found them very satisfactory and has sev- Bridge Brass Tube l6 - k feed 7# eral of the large size Federal arcs in opera- 2¢-- Radio tion at the principal Naval Stations. ^10 M\ Electrode In the large Poulsen arcs it has been ll eÑlafer Copper negative elec- Feed , usual to rotate the carbon or . Q- trode and in both of the arcs here shown, 3l,Stdi fe copper or positive electrode is water - i...:11'4' I the B 44-1 sr Waste Good fif- cooled. However, this may be submitted .5 """a Hole #/03 1 I by extending the supporting pieces of the fora "die.:-. . o ater Feed copper electrode down below the slate or Copper Pole Base Rod _ For nsldeof base and fitting a number of metal marble Co ec rode cooling flanges upon it. Several of the ;II/Holes pp a smaller size Poulsen generators, such as B-32 /,14-414 1`76 j/, up to 3 K.W. capacity, have been success- a foe /ron Reducing Copper Electrode Collar fully operated by air-cooling. /6-1 ;lb - -Bushing : B32Tap This cooling can also be greatly enhanced . by forming cooling ribs or flanges on the ,I %l'' - ¢Port ah., Lii ÑiN ,1, Ilei Jb // wall of the gas jacket, as shown in Fig. 4-B. 1Jo 0. f i %s4 In the present arc designs the carbon elec- -l_ ; ih /6 1 lQ ' . r Abo'41I -' 1rol''' section A A trode is stationary, and this has proven sat- Brass ;Vent _ _ isfactory in the smaller size arc generators Port 2 Gas of standard type, as it is not necessary to Spiral` Spring' rotate the carbon electrode, except in units larger than from 3 to 5 kilowatts. Gas Release Valve :Alin' F1 G. 3 The arcs here shown are fitted for illuminating or other gas, which is let into the gas chamber surrounding the arc, thru a inch pipe threaded into the wall of the IIIIIIIIIIIIIIIIIIHIIIIIIIIIIHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIHIIIIIIIIIIIIIIII IIIIIIW.!IIIIIIIIIIII IIIIIIIIIIIHIIIIIIIQ chamber. The Constructional Details of the y¢ -K.W. It is important to note that the amateur Arc Are Shown in the Above Drawing. If should never build one of these arc gener- the Dimensions Are Carefully Followed the ators without fitting them properly with Amateur Will Have Little Difficulty In Build- safety (pop) release valves, which are ing the Arc. The Method of Connecting the shown in both of the designs herewith. Arc Is Shown at the Left, The Choke Coll Either these valves may be made by the In With the machinist doing the and Resistance Are Connected Series experimenter or by Is Similar mechanical work on the arc, or they may be the Arc. The Rest of the Circuit purchased from any engineering supply to the Ordinary Transmitter Circuit. house. They are worth anywhere from 75 cents to $1.25, and are usually adjustable so that they can be set for various release --Gas Jacket 11IIHHIHIHHIIIHIIIHIIIIIIIIIH pressures of, from five to twenty pounds. . .. Copper Ì1111111IIlI/ / /Di A. Showing The gas chamber is made air -tight at the the method of top and bottom where flanges fit against Electrode 1111111111111111QII- -.... cir- pimim1 fastening the the top and base members, by placing copper elec- cular asbestos gaskets between them, as 1111..w.Lig Sate Base --- -- jmlI VIII trode to the shown in the drawing, Fig. 2. base also the method of As will be seen, the top electrode or car- placing the bon cap is pushed dqwnward by pressing Coohnes on the knob "J ", so as to short -circuit the II'II I I IIIIIIII cooling flan- / ges. Recent arc and start it. The carbon electrode is I , -- Ili 11 1 ililil01l improve- simply pushed down, and then released, ugáwm 1ïi1I111111Illjlllll ments have when the arc forms and the length of the mum u b r o u g h t arc can be accurately adjusted by means of . -___ about tho use ". NM= .. the feed screw "K Ili of tungsten in Fig. 2, is . shown Illt electrodes In The smaller type arc, 11//IAI blast, but the `Copper or Steel III IWIIi arc transmit- not fitted with a magnetic arc shown in Fig. 5, has this feature. Cooling flanges A B ters In place larger of the carbon Those wishing to experiment with a mag- and copper. netic blast on the arc shown in Fig, 2, may suitable electro- Wrought Iron Yoke- B. The gas easily do so, arranging a /60 Jacket with magnet co- axially with the copper electrode. the cooling as shown in the design in Fig. 5. to drill holes Iron flanges Another way, would be mounted as sides of the gas jacket of the Q 6 Wire thru the two j shown. arc, shown in Fig, 2, and in this case, the ariv Length Wad Core Il1111111' d Iijl; C. Details of jacket should be of some known magnetic » !3 --Core Of °_ II ] Bound the magnetic metal, thru which holes can be projected the 6lihl,,;I!_ I. 11 blast con- two magnetic coils. The outer ends of the struction. magnet cores would be connected of course, iron yoke. somewhat in the o Magnr : D.This shows by a wrought ltibgnet the method shown in Fig. 4-C. MagneticAeon 2 y}1111111111W manner Coil L cod r of construct- The diameter of the carbon electrode in bas Jacket ` f 111)11 1. ing the choke any of these arcs, for K.W. rating, is (Brass, Etc.) Taps colt used In one -half inch. A % K.V. arc carries over -Coll t h e primary View of Arc a range of 20 to 25 miles and more under Vertical circuit of the for speech Fitted with Magnetic Blast Detail of "Choke Coil" for Use arc. favorable operating conditions C in Primary Side of Arc. transmission. A much greater range may be obtained of course, when, transmitting FIG.4 0 1111111111111111111111111111101111111

www.americanradiohistory.com 354 RADIO AMATEUR NEWS January, 1920 undantpt radio telegraph signals. Of course the arc must never be started with- Mica condensers are often used in the out a suitable resistance in the circuit, or ocsillating circuit of the arc, and air in- 42w, sulated variable it will blow the fuses out ; also a properly condensers have been util- designed ized many times, where the plates choke coil must be used in series faâ.,y,,y'se/ y are sepa- with the arc. The rheostat placed in rated at least 1 /16th of an inch or more, series to prevent with the arc, as shown in Fig. 6, may be an FQCeOÍF breaking down due to the surges adjustable water resistance, but the best flanges of radio -frequency energy produced by the method is to use a resistance wire rheostat arc in the resonant circuit. of the usual coil type. Any rheostat that The design for the magnetic blast arc gen- will carry about five amperes, without un- erator shown in Fig. 5 is suitable for opera- due heating will serve the purpose. tion in a cool manner, at loads of 1% to 2 For radio telephoning, a hot wire am- K.W. Those desiring to build % KW. arc meter and a microphone of this same type should simply follow the are placed in the dimensions ground wire as shown in Fig. 6. The oscil- given for the gas chamber and lating circuit connected across the arc, may the carbon and copper electrodes in the comprise a variable condenser placed in =r detailed drawings for the previous design, in Figs. I. oil, -such as castor oil, to improve the in- Cal and 2. Fig. 7 shows the photo- sulating qualities. The condenser should C/alrps- -Fibre graph of the arc. have a capacity The magnetic blast coil is connected in value of .001 to .003 micro - series farad. The energy is transferred to the with the arc itself. In striking the aerial circuit by means of an ordinary arc with this design, it is only necessary oscillation transformer. to press downward momentarify on the Volt and ammeters angular projection shown, which slides the may be connected in carbon the positions shown in the diagram, and Fie.S holder downward until the carbon proper fuses rated about 10 and the copper touch. at amperes and As a switch should be placed in the primary This Shows the Type of Arc Using the Mag- the two electrodes are separated, the circuit of the arc. netic Blast. arc forms in the usual manner and the length of the arc, Several improved hookups for modulat- sulated which is usually about with six layers of oiled linen for TA inch, is regulated by the ing the arc radio -frequency energy both a length of seven inches carbon feed at the center. screw to the left of the drawing, Fig. 5. for telephony and telegraphy are given in Over this should be wound several of the newest radio four layers Some arc generators have been fitted text -books of No. 14 B. and S. gage D.C.C. or enameled with substantial which every experimenter has at hand or blue or red glass windows magnet wire, bringing out a tap from the about one inch in diameter, placed opposite can consult at his library. end of the 2nd, 3rd, and 4th layers, Two excellent works giving to per- the arc in the gas chamber wall, so that the official mit of varying the reactance or self in- the length and operating U. S. Navy hook -ups of arcs, are Robin - qualities of the ductance of the winding. arc might be viewed. This is son's "Manual of Wireless Telegraphy," After the not neces- and "The Principles wire has all been wound on in sary however for ordinary purposes on Underlying Radio this manner, the coil should be covered with small arcs, Communication," published by the Signal and the adjustment of the arc several layers of oiled linen, being care- is carried out to produce the maximum Corps, U. S. Army; Radio pamphlet No. 40. ful to fold it tightly A suitable choked over the ends of the radio -frequency oscillations in the antenna, coil to be used in series winding, and then the two long projecting or closed with the primary side of the arc to prevent oscillatory circuit. ends of the core are bent over and inter- Some arc sets have been the radio- frequency oscillation from back- meshed. fitted with a hot ing The junction of the core wires wire ammeter, in both the closed oscilla- up into the primary circuit, may be should be firmly bound with constructed as follows: some pieces tory circuit as well as in the antenna oscil- of iron or copper wire, so as to make a latory A core may be made of iron wire about circuit, in order to keep a check good firm joint and the completed closed on the degree of resonance and No. 20 gage, and about 16 inches long. core the aTnount Then the choke coil can then be mounted on a of energy passing in either circuit at any bundle of iron core wire is in- base. instant. Our Supplement IN presenting to our readers the wireless the Greenwich meridian. The time differ- Constantinople 7.00 P. M. map which forms a Copenhagen supplement to this ence as you will see from the clock dials, 6.00 P. M. issue, we sincerely Denver 10.00 A. M. trust that it will is seven hours exactly. Dublin meet with approval. This map is intended 4.35 P. M. to be mounted Now remember that when it is noon on Hamburg - 6.00 P. M. on heavy cardboard and the Havana 11.31 A. M. framed under glass Greenwich meridian, the time west of Havre (France) 5.00 P. for display in the radio Greenwich M. station. The chart has been compiled ac- is slow to the time of Green- Hongkong 1.00 A. M. wich mean time, while to the east of Green- Honolulu 6.30 A. M. cording to the latest information, giving Lima (Peru) 12.00 Noon the names wich the time is fast. Thus the time at Lisbon as well as the call letters of Denver, 4.24 P. M. the most important radio stations of the which corresponds to about 105 °, Liverpool 5.00 P. M. world. is seven hours slow to Greenwich time. London 5.00 P. M. Therefore, if the Bordeaux Madrid - LOO P. M. An innovation station, which Manila 1.00 A. M.' which has not been shown is on the Greenwich meridian Melbourne on a wireless map heretofore was sending, 3.00 A. M. is the time - while your clock showed 10 A.M. (Denver Mexico City 10.24 A. M. finder, or time computer. Natal (South local time), the actual local time at which Africa) 7.00 P. M. It will be New York 12.00 Noon seen that on the top and bot- Bordeaux was sending would be 10 plus 7, Paris 5.00 P. M. tom of every meridian a clock dial has or 5 P.M. The same procedure should be Petrograd 7.01 P. M. been inserted, showing the time on this used when converting the time for Rio de Janeiro 2.00 P. M. particular other Rome 6.00 P. M. meridian. The time, as is well meridians for the various localities. San Francisco- 9.00 A. M. known, is exactly the same thruout the Inasmuch as new great radio stations are Santiago (Chile) 12.00 Noon length for the entire meridian. The time continuously Sitka (Alaska) 800 A. M. is computed erected, the reader may mark Stockholm 6.00 P. M. universally from Greenwich, such stations Vienna 6.00 P. M. commonly called on the map himself in red ink, G.M.T. or Greenwich as quickly as such stations are opened and Yokohama 2.00 A. M. st /con Tinte. Thus when it is noon on the made public. Greenwich meridian, the difference of time At places marked the time noted is in the will as indicated The chart also shows the various dis- morning of the following day. be on the different clock tances, dials all over the globe. From this the local and a rough calculation may there- For cities situated in countries where "summer" fore be made by anyone in time has not been adopted, one hour must be sub- time can be readily computed without much order to corn - tracted from the time given in the above table, dur- trouble by anyone. As will he seen, every pute the distances between different points ing the spring and summer months. whenever this becomes necessary. Eastern" time includes: New York, Boston, meridian, which is really every 15th, rep- Philadelphia Baltimore, Washington, Richmond resents exactly one hour. There are 360 TIME DIFFERENCE. Norfolk, Charleston, Buffalo, Pittsburgh, Montreal, meridians all told, but for the sake of Twelve o'clock noon United States standard Quebec, Ottawa, Toronto, etc. clearness the map shows only every 15th, Eastern time as compared with the clocks in the "Central," which is one hour slower than East. each one of these representing a difference following cities: ern time, includes: Cleveland, Chicago, St. Louis, Aden (Arabia) Minneapolis, St. Paul, Milwaukee, Kansas City, of one hour between the one preceding and 8.00 P. M. Omaha, Alexandria 7.00 P. M. Indianapolis Cincinnati, Detroit, New the one following. Amsterdam Orleans, Memphis, Savannah, Pensacola, Winni. 5.20 P. M. peg, etc. your station is in Denver, Colo- Athens 7.00 P. M. Suppose Berlin 6.00 P. M. "Mountain," which is two hours slower than rado, which is at 105° longitude off Green- Berne 6.00 P. M. Eastern time, includes: Denver, Leadville, Colo. wich. Let its say you are receiving a mes- Bogota (Colombia) 12.03 P. M. rado Springs, Helena, Regina (N. W. T.), etc. Bombay (India) 10.30 P. M. sage from the French station at Bordeaux, Bremen "Pacific," which is three hours slower than East- as you will note is on 6.00 P. M. ern time, includes: San Francisco, Portland (Ore- !¡ France, which nearly Brussels 00 P. M. gon), Victoria, Vancouver, Tacoma, Seattle, etc.

www.americanradiohistory.com January, I920 RADIO AMATEUR NEWS 355 Crustal and Vacuum Tube Detectors BY E. M. SARGENT

THE purpose of this article is to give feet cubes. The mineral should be taken blunt piece Of No. 18 copper wire makes a the experimenter a good understand- from the holder about every week or ten good contact for this mineral and enough ing of how his detector operates, to days and thoroly scrubbed with soap pressure may be applied so that it will not tell how to get the best results from and water and then dried with a clean cloth, jar out of place easily. it and also to compare the relative care being taken not to handle the surface Iron pyrites is very nearly as sensitive as merits of crystal and vacuum tube detec- of the mineral after it has been scrubbed. galena and can be used with medium pres- tors. The crystal. detectors will be taken sure on the point of contact. It can be up first. used in a detector of the carborundum type, The most common minerals used for but will work better in a catwhisker detec- crystal detectors are galena, carborundum, tor with a slightly heavier contact wire iron pyrites, and silicon, and each one re- than that used for galena. This mineral quires a different type of contact to get the gives very satisfactory results when used best signals. Galena is the most sensitive, in a station where considerable transmit- carborundum is the most rugged, and is ting is done. also fairly sensitive, iron pyrites is fairly rugged and somewhat more sensitive than If silicon is to be used, the catwhisker carborundum, while silicon has neither detector can be somewhat modified and great or ruggedness, and is rap- made adaptable for it. with a piece of sili- sensitivity the Correct Design of a Galena a station hav- This Shows con the best signals will be obtained if the idly falling into disuse. In Note the -Circuiting Switch ing a powerful transmitter near the re- Detector. Short contact is made by an iron needle resting is Mounted on the Detector Base. ceiving set it is difficult to keep a point on horizontally across the edge of the mineral. galena unless special protective devices are A medium pressure may be used to keep the point from out. To find a point used, and a carborundum or pyrites detec- Galena should not he mounted in Woods jarring found to give the best results. even the needle is moved back and forth along tor may be metal or any similar material, because the However, for a receiving station not the small amount of heat that is used in edge of the mineral. Silicon should troubled in this way galena is better and is liable to also be wrapt in tinfoil before being mounting it in this manner placed in the holder, will give surprising results if used cor- decrease its sensitivity. but .even then it does rectly. not compare favorably with galena, and When a galena detector is used in a sta- should not be used where the best results The design of a galena detector should tion having a transmitter the detector must are desired. be such that the contact may be of the be protected with a short circuiting switch. "catwhisker" type, and have a universal If this switch is properly connected across Nearly all crystal detectors will prove control movement, making all parts of the the galena the point will not knock out when more sensitive when used in conjunction mineral accessible. The "catwhisker" when the transmitter is used. Use a rela- with a 3 to 5 volt battery and potenti- should be a piece of No. 28 B. & S. age timely heavy single blade single throw ometer. The reason for this may be seen silver wire, two inches long, one end firm- switch and mount it right next to the from the characteristic curve, Fig. 2. It ly fastened to the handle or other device by detector. Then run leads of small wire, must be remembered that the radio signal which it is to be moved, and the other end about No. 28 B. & S., from each side of the picked up by the antenna has a frequency clipped at an angle so as to form a sharp detector to each side of the switch, keeping far too high to affect the diafram of a point for making contact with the mineral. the leads parallel and close together. This telephone receiver, or to be audible if it This two inch wire should be looped in a will tend to eliminate inductive effects and did affect the receiver, therefore, it must semicircle and arranged so that the point will not appreciably affect the efficiency of be converted into some audible frequency will rest lightly on the galena. It is very the detector. These leads must be as short before it can be heard. In other words. important that this contact be light as the as possible to still further reduce the possi- it must be distorted in some way from its sensitiveness is considerably decreased bility of their picking up any energy from original form. Suppose that two signals. when any great pressure is put upon it. the transmitter. When the switch is one of amplitude E. and the other of am- The galena may be held in a clamp, and heavy single blade single throw switch and plitude E. are being imprest on the must be wrapt in tinfoil before it is fast- mount it right next to the detector. detector (Fig. 2). During one -half of the ened into place. This has the double ef- connected in this way, the current picked cycle, E. produces a current in the detector fect of decreasing the resistance of the up by the secondary of the loose coupler (and thru the phones as they are in series mineral and of increasing the sensitive area, will practically all flow thru the switch with the detector) of amplitude I. and as it will always be found that the best as the impedance in that path will be many during the other half of the cycle a current points on galena are near the place where it times lower than thru the detector, and in the opposite direction of amplitude Is is is fastened into the holder. This, latter owing to the non -inductive leads from the produced. Due to the irregularity in the effect is of course due to the decreased re- detector to the switch practically no volt- shape of the characteristic curve I. has a sistance at these places. Pieces of galena age will be induced directly into the de- greater positive amplitude than I, has having slightly uneven surfaces are as a tector to burn it out. negative. Therefore the resultant current I. rule more sensitive than those with smooth whose value depends on the difference of flat surfaces and which break up into per- Sometimes operators experience difficulty ,n getting a good point on a catwhisker de- amplitudes of I. and Iu will flow thru the tector, and blame the trouble on the min- receivers. One of these resultant currents eral without further investigation. In nine will flow for each wave train picked up cases out of ten the trouble will be found to be with the contact wire. In a cat-

i whisker detector the wire does not bear heavily enough on the mineral to be self - cleaning, and consequently when it has been used for some time it gets too dirty to make good contact, with the result that the mineral appears to be dead. If the contact wire is freshly clipped every three or four days no trouble will be experienced from this cause, and the operation of the detector will be more satisfactory as a whole. An efficient design for a galena detector is shown in Fig. 1, together with the protective switch. An excellent detector for use with carborundum has been described by Air. R. F. Gowen in the October issue of the Electri- cal Experimenter. In this detector it will be noticed that considerable pressure can tie applied between the contact and the mineral. Unlike galena, the sensitivity is not appreciably de- Here the Curve Shows What Happens When Curva Illustrating the Advan of carborundum Characteristic contact and for this a Positive Potential Is Applied to the De- a Battery in Connection creased by a heavy tage in the Usa of be made very rugged. A tector. With Crystal Detectors. reason it niay

www.americanradiohistory.com 356 RADIO AMATEUR NEWS January, I920 by the receiving antenna and the signal results that could be obtained with a single heard signal is imprest between grid and fila- in the telephone receivers will there- good gas tube by an expert operator. The ment considerable distortion fore have a frequency corresponding to the experimenter should may take place remember that the and the tube will apparently be a good one. wave train frequency of the transmitter. fact that the navy or army used a certain Tubes of this type This is an audible frequency. Referring type of tube make excellent ampli- widely during the war does fiers but are poor detectors until the work- again to Fig. 2, it will be seen that the not indicate that this tube is a particularly ing point is corrected. signal E, has an amplitude so small that it sensitive one. On the contrary the army does not reach the bend in the curve and and navy tubes were as a rule inferior to A good test for a vacuum tube detector therefore it is not distorted and will not the tubes used by the amateurs before the is as follows. By good detector is meant a be heard in the receivers. war and were used only because of their tube that will pick up weak signals. A Suppose now that a steady positive po- uniformity and reliability under all dif- source of dampt oscillations should be tential of value E., Fig. 3, is put on the ferent adjustments. available. A wave meter may be used, or detector. The voltage acting on the de- The if there is none at hand, a coil and con- gas tube, of which the well known denser excited tector from signal E. will now be the sum old style tubular audion is a good example by a buzzer will do. Set up of E. and E. or at any instant e, = E, max has a characteristic this miniature transmitter and then about curve that follows the three feet from sin wt + E, What has been accomplisht is general form of that of a high vacuum it connect a similar coil that the constant E. has been added to every tube, but has irregularities and condenser. Run two leads one from value in it, (Fig. 4). each side of the condenser of E, and therefore on the diagram When the tube is adjusted so that the to the middle the imprest voltage has been shifted to the working point terminals of a DPDT switch. Connect the comes at one of these ir- vacuum tube detector right by the amount E.. This is called regularities extreme sensitivity results. to one throw of the "shifting the working point". The same Suppose the switch and a good galena detector to the plate potential and filament other. Next put on happens to E. with the result that the current are so adjusted that the working the telephones con- positive alternations from E. are now nected to the galena side and get the best point falls at point B, Fig. 4. Then either point greater than the negative, a distorted cur- the positive or negative half possible on the mineral and get the of the cycle of coil and condenser rent is produced, and the signal that was the imprest voltage will cause an in- in tune with the trans- formerly inaudible is now made readab e crease in the plate current, and instead of mitter. Note the strength of the signal, having the difference of the two halves of then put on the vacuum tube telephones, the cycle for the resultant as in the crystal detector, we have the sum, resulting in a very strong signal in the phones from a relatively small imprest E.M.F. While it is difficult to maintain the working point at exactly the right place, it is by no means impossible. The easiest way is to have a very fine adjustment on the filament rheostat Varying the filament current shifts the working point indirectly by changing the height of the characteristic curve. The working point may also be shifted directly by putting a steady potential (usually negative) on the grid. A very good way to get the correct amount of steady grid potential is to connect the filament rheostat in the negative lead of the Showing the Connections of a Rheostat o "A" battery (see Characteristic Curve of the Gas Type Fig. 5). Then make an Which Permits Critical Adjustment. Tubular Audlon. extra arm for this rheostat and connect it to the filament end of the receiving coil. in the phones. At the same time the dis- By varying the position of this arm, the and retune and note the strength of the tortion of E, has been increased and the voltage drop between the negative side of signals in these receivers. If the signal resulting signal is louder. If too much the filament and the receiving coil will be was of moderate strength on the galena it steady voltage is applied the working point changed, and if a leak resistance of 4 or should be much louder on the tube. Now will be shifted to point B, Fig. 3, and no 5 megohms is put across the grid condenser move the transmitter away until this negative the signal distortion will result. The correct value potential will be imprest on is just audible, then throw the switch again for E. is somewhat critical and to obtain the grid. Practically all tubes require some to the negative potential mineral and do not be surprised if the best results the potentiometer should on the grid for best the signal is both louder and operation. For those that require positive clearer on the be capable of fine adjustment. It will also mineral. If this is the case throw the switch be noticed that the steeper the portion A -C (as in Fig. 4) put the rheostat in the positive lead of the "A" again to the tube and adjust the work- of the curve the greater will be the distor- battery and connect ing the second arm of the rheostat as before. point until the signal is at its best. tion and the louder the resulting signal. With Vacuum tube detectors may be The characteristic most tubes this can be done, and the roughly curves of vacuum tube made divided into two groups, high vacuum tubes tubes are steeper than those of crystal de- better than galena, but some and low vacuum or gaseous tubes. The tectors hence louder signals are obtained are so poor that any adjustment will not latter are by far the more sensitive. The from the vacuum tube where a moderately improve them. The author has made tests high vacuum tubes are very steady in strong voltage is imprest on the grid. similar to this one on vacuum tubes of operation, have no critical values for plate However, a very important fact, and one the kind now licensed for amateur use and potential or filament current and as a rule that is many times either overlooked or un- found that a good piece of galena was bet- give uniform results, and their operation known is that a vacuum tube may bring in ter in many cases. In performing this test under certain conditions and with certain moderate signals very loud and at the it will be necessary to change the adjust- circuits can be predicted. For this reason same time be either inoperative or inferior ment of the receiving condenser slightly they are very good for laboratory experi- to a piece of mineral on weak or long when the shift is made from ments intended to check results dis- the vacuum arrived at tance signals. The reason for this is read- tube to the galena. The reason for this is theoretically or mathematically. They ily seen from were widely used during the war because the characteristic curve and that the tube, leads, socket parts, etc., have the majority of new operators had never is analogous to that described for the an appreciable capacity, sometimes as high seen a vacuum tube and kne -r little or noth- crystal detector. The working point may as 30 m.m.f. and this added to the con- ing about its operation, and to simplify the be so far up on the curve that detection or denser capacity increases the wavelength adjustments on receiving apparatus, high distortion will not occur for a very weak of the circuit somewhat. The difference vacuum or "hard" tubes were used, some- signal and at the same time the curve may probably will not be more than 2 or 3 de- times with amplifiers to obtain the same be steep enough so that when a moderate grees on the condenser scale. Dr. de Forest on the Radiophone Editor Radio Amateur News: vocated the probability that the radio phone country and you are the first editor to point I have just read with great interest your must supplant the radio telegraph, and it out this situation. ' timely and well- stated editorial in the is only very recently that the art has pro- You may be quite sure that we will co- RADIO AMATEUR NEWS for December on duced a low power, low priced, And reliable operate in every way with every effort to "Developing the Radiophone." This article radiophone which the amateurs can acquire make the radiophone popular among the meets with my heartiest approval and I am and successfully operate. amateurs. greatly pleased that you have taken this ad- There is going to be an enormous devel- Very sincerely, vanced view of the situation. opment and wide-spread application of the LEE DE FoREST. As you know, I have for many years ad- radiophone among the amateurs in this New York, January 2, 1920.

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS 357 Loop Multiple Aerial Switch By John G. Merne, L. M. T. County Technical Instructor, Leitrim, Ireland.

MANY amateurs who have had the length of the aerial loop in action. If loop 1 is wound to 150 meters and the other pleasure of persuing Professor + e Knoll's account of his experiments IIlmorv lane. Zoo,/ loops in ratio of 1, 2, 4, 8, the calculations with loop aerials as related in the August are as follows: issue of Electrical Experimenter, will without doubt be constructing apparatus to re- Stud 1 150 meters ceive signals in the manner suggested Stud 2 300 meters therein. Stud 3 450 meters Stud 4 600 meters This has prompted the writer to offer the Stud 5 750 meters following ideas, which if embodied in such Stud 6 900 meters It/ 5.11 ,nsJAY, , Okla or give a wide range of tuning, and rrtm e+Y.ann.na' Stud 7 1050 meters a set will oled meal n rNOY ,MYh at the same time ease and simplicity of OYCY, a man 'mist Stud 8 1200 meters the aid of the Stud 9 1350 meters making adjustments. With :'.y:N;a°wr aerial switch, any loop can be put in action ro,..n n. ..,V. . Stud 10 1500 meters sr es a.aner.., .,m orn. o or any multiples of same used and with the o Stud 11 1650 meters use of the circuit switch, each circuit as -°own rt47roa++i% Stud 12 1800 meters shown, can be used independently. This Stud 13 1950 meters arrangement does away with a number of Stud 14 2100 meters switches and embodies all the actions of same in the function of one switch. /vio/ S.ihh If loops are wound to a larger wave top length than those given in the tables, the Fig. 1 shows 4 loop aerials at the wave lengths for each stud on the aerial 1 loop is wound of the drawing. Number switch can be calculated easily if the ratios say a wave length of 100 or 150 to give, of 1, 2, 4, for loop to. meters. 8 each be adhered Loops can wound a form such as to a wave length of 200 be on No. 2 loop wound described by Professor Knolls on page 328 or 300 meters. of the Electrical Experimenter. Having No. 3 loop wound to a wave length of 400 constructed the form, wind each coil to or 600 meters. wave length required, soak in melted wax to a wave length of 800 and when cold remove the coil from form No. 4 loop wound and tape it up so that the four coils in 1200 metres. fg or ratio of 1, 2, 4, 8 can be placed side by In this way: On,' s.,. side in a flat box on which the aerial switch can be mounted and connections made to 1 a ratio of 1. Loop would have At the Top of the Drawing 4 Loop Aerials loops. This a very compact ratio of 2. One Having a should make Loop 2 would have a Are Shown, Each Different and one that 3 have a ratio of 4. Wavelength Range. The Aerial and Circuit aerial easily carried about Loop would Switch Connections Are Also Shown. can be placed in various positions for ex- Loop 4 would have a ratio of 8. perimental purposes. The aerial switch is so designed that Switch Meters loops loop is a separate unit and indepen- on stud in action The circuit switch is shown in Fig. 1 each with connections to the loop aerial switch. dent of every other loop, by this means, 1 100 dead ends are done away with, which is 2 200 When the switch blade is on Stud 1 (in an important factor in wireless apparatus. 3 300 black), working clockwise, the connections When switch blade is on the first stud on 4 400 are as shown in Figs. 1 and 2, page 328, 5 500 Electrical Experimenter. When the sector working clockwise, Loop 1 switch the top 600 moves 2 is in action, Loops 2, 3 and 4 out when the 6 to Stud and then on to Stud 11, switch blade is on the second stud on the 7 700 working clockwise, the tuning inductance top sector, Loop 2 is in action and Loops 8 800 is in as in Fig. 3, page 328, Electrical Ex- 9 900 perimenter. When 1, 3, 4 are cut out. When the switch blade the other end of the 10 1000 switch blade comes on to - is on stud 3, Loops 1 and 2 are connected; the studs at left 11 1100 hand 1 Loops 3 and 4 are cut out. When the bottom side of switch from Studs switch blade is on Stud 4, Loop 3 is in and 12 1200 to 11, the circuit is the same as in Fig. 4, 1300 page 328, Electrical Loops 1, 2 and 4 are cut out and so on up 13 Experimenter. The to the end of sector. 14 1400 apparatus being connected to earth with tuning inductance and variable condenser Assuming that the wave lengths of each This arrangement makes things very in the ground circuit. loop are as follows: simple as the experimenter knows from the number of the stud covered, the wave Fig. 2 shows the construction of the Loop 1 100 meters aerial switch, also the circuit switch. The Loop 2 200 meters handles are removed in the plan and the Loop 3 400 meters metal parts colored black for clearness. Loop 4 800 meters In conclusion, experimenters could con- Then we have the following combina- struct a number of these multiple loop tions of loops: aerials and have same fitted into flat boxes so that various wavelengths could had Loop 1 100 meters be Loop 2 200 meters when required. Other improvements will suggest themselves to those who are in- Loops 1 + 2 300 meters 400 meters terested in the question of compact re- Loop 3 ceiving apparatus. Loops 3 + 1 500 meters Loops 3 + 2 600 meters Loops 3 + 2 1 700 meters 800 meters PLANTS AND WIRELESS Loop 4 TELEGRAPHY. Loops 4 + 1 900 meters Loops 4 + 2 . 1000 meters One of the most extraordinary recent Loops 4 + 2 + 1 1100 meters discoveries in regard to plants is that they Loops 4 + 3 1200 meters are "conscious" of wireless messages. Ex- Loops 4 + 3 + 1 1300 meters perts who have experimented in the matter Loops 4 + 3 + 2 .1400 meters declare that plants receive and make a response to wireless messages. and that the All these ratio changes are brought about response can be detected by the newer elec- by means of aerial switch connections trical instruments. The latter ratios are so sen- shown in Fig. 1. Keeping the above sitive that they can detect and register the ex- the Construction of the Aerial and in mind, we determine the following Showing minutest internal movements in plants. ample: Circuit Switches.

www.americanradiohistory.com 358 RADIO AMATEUR NEWS January, 1920 Designing An Amateur Transmitting Antenna By E. T. JONES

NOW that the Amateurs have acquired to the wavelength of two hundred meters creased to one hundred and seventy -three the prestige which was forthcoming as prescribed by law. Columns after col- meters. A raise in the height of the same for some little time, and have most umns have been given to the advancement type antenna but ten feet has caused an in- of the "Influential" Engineers and Scientists of the tuning of the circuits both open and crease of twenty-three meters. Therefore i closed, the advisability of providing high as we raise the antenna we will have to voltage transformers to reduce the amount Antenna .50 feel /n /A^igh/ of capacity required and last but not least t f the elimination of unnecessary losses which Antenna 60 fee/ in height r occur from the lengthy leads employed by ZOO the amateur to connect up his instruments; 110 however not one single author has to my MO knowledge advanced Information in respect to the correct design of antenna which /70 should go with these short wave transmit- /60 ters, and therefore, no matter what is done /SO in the operating room proper, best results /a cannot be obtained unless the antenna is properly designed in respect to its natural /so period. The average amateur is not satis- /20 fied with the antenna which would be high- //o JC 43 57 31 Y ly efficient éS -r N Qi 9J YS KV for the transmitting waves pre- /ao [mg/h o/s,aan feet scribed by law, for his receiving set; as 40 45 50 . 0 60 65 Al 75 SO 6S 7093210 he does not care to be handicapped in this Zenith ofsA07/2 /n feet fgl respect. There is then, but one solution fig. 3 and the correct one, provide a separate .. With This Direct Reading Graph You Can antenna for transmitting and the sky can be Easily Design Your Own Antenna. considered the that Showing What Happens When the Antenna limit for of the receiv- Is Raised to a Height of Sixty Feet. ing set. pulling strings at Washington for their wel- Design of the Antenna. fare, let them not forget their duty towards satisfy ourselves with a shorter one, for correct and these men who have fought and won their With . the valuable assistance of several efficient transmission on 200 battles several times. It is their duty to graphs which were taken from Dr. Austin? meter wavelengths. maintain the high standard which was ac- works the Amateur will have before him In order to use this same antenna at a corded them when their sacred privileges very valuable assistance which will permit natural period of one hundred and fifty were at stake; by adhering to regulations him to construct an antenna best suited for meters we will have to make the length and reducing to a minimum the amount of the operation of his transmitting on two - fifty -one feet; exactly nine feet shorter "chewing the rag stuff" which goes on from hundred meters. than when the antenna was ten feet lower. morn till night. The antenna is composed of number four- A graph of not much use other than While the above regulations are the teen bare copper wire and comprises FOUR acting as an illustration of what happens easiest to adhere to, the average Amateur WIRES spaced two feet apart thruout. to this same antenna, when raised to a does not know how to tune his transmitter The four leads should be twisted together (Continued on page 385) at a point ten feet from the ground and then brought into the sending room. Antenna 40 fee/ in height By referring to Fig. 1, it will be seen that Antenna 60 feet /n heght too r--,-T the type antenna described above if raised

i ¡ 1 to a feet and stretched NO /901-1 11 1 i height of thirty to a length of sixty feet the natural period 000 /eó of this antenna will be one hundred and /ro A fifty meters. If lengthened to eighty-six AO /óol feet the wavelength would be -two hun- WO /J,O . dred meters and at this point it would be SM I impossible to insert inductance at the base I of the antenna. (The Open circuit Oscilla- ; do i 1 tion transformer Inductance.) It would zo . be found that several turns of the usual too Amateur helix could be inserted at the base of the antenna if it was reduced to a sixty- 100 ' ¡ foot length as the wavelength at this point 00 SO - 60 10 110 40 IS 50 55 40 6$ /O 7 SO 81 f0 99 AM A W /e7 /X /10 /a /W.NO /V A is hut one hundred and fifty meters. length Span in feet length of soon in feet of Fig. 2 shows the wavelength of the same fig 2 fig. 4 type antenna at a height of forty feet. By A referring to this graph it will be seen that An Increase In the Height Carries an In At a Height of 80 Feet a Maximum of 500 crease in the Wavelength As Shown by This if we still desire to employ an antenna Meters Can Be Reached with an Aerial Graph. sixty feet in length its wavelength has in- Length of 180 Feet.

Perhaps you do not recognize what this not speak of them as telephone receivers, are just now engaged in writing to our means. We'll say it is a mouthful! Next simply call them "dien -haw" which not only Chinese correspondent to find out what a time you get tired of saying "radio" just sounds nicer but is Chinese as well, meaning few simple little things such as wave- call it wu- shien- dien -bao for a change. Yes, "electric talk instruments." How do they length, 15 -step amplifier, heterodyne re- sir, it is the same old wireless, only it is get that way, we ask? ceivers, Honeycomb-Litzdraht-variometer- in Chinese this time, and if you don't be- Then if you own a "tin lizzy," you will coils, and similar ones mean, when trans- lieve it, we will give you the translation now have to call it "tzi -shin -cha," meaning lated into chop- sueyédoiseI verbatim, for wt1- skirl- dien -bao means "self- traveling carriage." (P. S. We for- P. S.1 It just occurred to us that the "without wires electrical message." We'll got to ask our informant what the Chinese Chinese probably cannot use Galena Detec- say it is descriptive, if nothing else. call their "self- traveling carriages" when tors. With such talk (look at headline) And the very next time you get tired of the latter go on strike and have to be the sensitive spot surely would be knocked wearing your "tin cans" on your head, do "horse traveled" or simply pushtl) We out.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 359 Clearing Traffic By "Sparks" iketchikan, Alaska.

A\lATEUR radio plants are now per - waste could have been saved by the sending by the number of the message with no mitted to open up and transmit to operator memorizing a certain form, the designation "NR." The operator's personal their hearts' content. In view of that right one, and using it. This operator of- sign should follow next, and every operator fact a few suggestions as to the handling fended further by acknowledging for a should adopt a personal sign as it helps in and disposition of amateur traffic may not tracing a message. The check, or number be out of place. With thousands of new of words next without the prefix "CK," amateurs, who have become interested in and not followed by the word "Radio" as the art thru war experience, it is important this has already appeared once (this is a that the handling of amateur communica- common fault). The date is always spelled tions should be done correctly and in a out, never say "date' -it's confusing. The business -like way. The habit once formed filing time should follow the date in fig- will tend to a better and more efficient ures. As the filing time is seldom re- trans- operation. mitted over land lines, this may be omitted, Let us first consider the matter of call- and the date followed by the double dash, ing another station. This station is lo- which indicates a separation of prefix from cated within easy communication range. address, address from body and body from Then let's not have any of the old time signature. This double dash should al- methods, which consisted in making four ways be used as it saves confusion. The or five attention signs, the station's call ten designation "To" is permissible in commer- or .fifteen times, "DE" once or twice and cial traffic, but in no case should the ab- adding your own call letters six or eight breviation "sig" be used before the signa- times, followed by several "Ks," "ARs," ture. The double dash shows that the signature is about to follow. etc. Make it a regulation call ; the attention sign but once, the station's call three Remember, I'm not holding up the gov- times, "DE" once, followed by your own ernment operators as models who use call letters three times. That's enough for correct procedure, for I've heard very, very any station who can hear you at all, to few operators of any class, government, know that you are calling him. In cases commercial or amateur, send a message where the station is almost within shouting correct to form. I once received a repri- distance, or even several miles away if mand in the service for "unofficial com- communication is good, even the regula- munication" and determined then and there tion three calls are not necessary; give that there would be no repetition. I ac- him a couple and sign once -make it cordingly learned the correct forms for all Ye Editor's Translation of the N's, R's, Q's transmissions, and find it best all round. snappy. Long drawn out calls only show Dashes Jazzed Out by and Miscellaneous I question me on up an inefficient operator and don't serve an "Op" When He Desires to Raise a sometimes have operators to clear the traffic. Use consideration, too, Station. parts of the form as I use it, it is so un- in your calling; listen first and see if the familiar, to them. Most of the present other fellow is receiving or is otherwise (lay operators adopt their forms from what message in this way: "N- N- N- they hear others using and by so doing, occupied with another station. He can't de handle two stations at once and you only N- W- W- W- rrrrnr they are almost certain to learn the wrong 1 1 He left cause unnecessary interference and get the rrurnr rrokr... -, -" way. Learn the right way first and it will no doubt as to his correct reception of the soon become a habit. You will find it good fellows "down on you" if you persist . message, but how foolish. in mussing up the air. The law calls for much easier to copy correct forms and get a listening period before calling, and ama- The handbook of commercial traffic regu- all the information, than to hunt out the teurs are not exempt from the radio regulations which should be in place on every number and check, etc. lations. If the station you call doesn't an- ship, and copies of which the amateurs can In acknowledging a message, call the swer after the lawful three calls, don't obtain from the government printing office sending station once without the attention in Washington, contains complete data on sign, say "R" a couple of times, give the persist ; if he were there he would have and let correct forms for sending, calling, acknow- message number followed by your per- heard you. Keep out for a while and "K" the other fellows, who are in communica- ledging, etc. Get one, fellows, and start sonal sign, your station call letters R R 1 NX tion, do something. your transmitting off right. Jump the other if more to come. Thus: "5AZ you get your man. Suppose fellow for useless sending, too. Here's a 5BR K ". The above method of acknowl- Now, after long, it is permissible you have a couple of messages for him. sample of the correct form for sending a edging being a little How you going to get 'em off? Probably message: send nothing else but what ap- to say merely "RK" when receiving a in marks, after at the end of each message and in like this: "Hr nr 1 ck 12 ck 12 pears the quotation calling series, something and signing ONCE. "Radio SS PHILA- giving the regulation acknowledgment, sub- fm Pittsburgh Pa date to -" and so on. for for that DELPHIA 1 NX 24 Twelfth 430pm ... stitute the number of messages received Where do you find any authority - at the end form? A common answer I have heard to - To " The word radio is the the individual message number, prefix and shows the count to be radio. of the reception. A more detailed account that question is, "Most of the commercial under dif- fellows use it, or something like it." Sure Then follows the office of origin followed and examples of acknowledging Nothing ferent conditions, such as when sending they do, but pity their ignorance. in the pub- annoys an operator more than to get a alternately etc.. will be found above, particu- lications which can be secured by applica- string of stuff such as the local radio inspectors. All the larly when he is trying to make a clean tion to the Only the forms and regulations governing radio com- copy, probably on a typewriter. be found therein. other day a well known passenger ship munication will waters called Give this matter some thought, fellows, running in these (Alaskan) in a business -like way. I'd me. She carries two first grade operators, and get going three hours like to come back into the amateur game too, both old timers. Altho only above where it formerly out and coming in strong, he called me and find it aces six. Not only was. I'm an amateur at heart now. have seven times, and signed off too, and followed that with on his first call for recognition but for been practically When commercial work, and finally my present each acknowledgment thereafter. whereof I in a form something government service, so "know he sent me one, it was you. similar to the one outlined above. I let speak ". I thank him to re- him finish and then requested Rivers have often been accused of form- peat the whole thing before acknowledg- for radio copying on a "mill" and trying better paths or channels ment. I was waves. This has been proven by extensive ing to make a decent copy as our originals to communi- are turned into headquarters. It couldn't tests. When it is necessary idea of the mes- cate with a ship and the two are separated be done, so I gathered an -tenth the signal is re- sage from his first sending, and using what by land but one follow- ceived as when the same ship enters the knowledge I gained from that and This Poor Bird Tried to Make a Clean Copy or whose to get my copy Refused to Picture mouth of the river upon near ing his repetition, managed on the Mill. Our Artist station is located. straight. Here double time and a useless His Thoughts. bank the receiving

www.americanradiohistory.com 360 RADIO AMATEUR NEWS January, 1920 A Case of Nerves By JULIAN K. HENNEY

ALL day long the steamer Rollybelle cabin except the wailing and crying noises stopt and prest the buzzer, its small had been plunging along in the incident to the high wind. Occasionally squeak startling the junior operator so teeth of a half gale which whistled Miggsby prest the test buzzer, which emit- that he nearly fell from his chair. The down Lake Huron from the north- ted a high squeak strangely harmonizing hardened mate even looked about him with east, stirring the water into perfect with the noises that came from without. a sort of shiver as he changed the position furor of foam and wash. The ship was At each gust of the wind and the follow- of his feet, firmly planted on top the con- a pretty sight in sunlight but tonight she ing heave of the steamer, Boyd looked denser case. Outside the wind still howled seemed to he trying her best to live up to apprehensively out of the porthole at his and mourned alternately, the rigging and her name. She was in fact a veritable "holy side, and then at the mate. The storm was stack acting like organ reeds in the high beginning to get on his nerves, yet he was velocity wind. Without much imagination afraid to go to the bunk room. The good natured jokes of the mate were always distasteful to his sensitive makeup. At length Miggsby broke the silence. "This wind," he said, "reminds me of the last night I spent at Breezy Shoals. The station was situated far out from town on the desolate shores of Cape Breeze where so many wrecks occur every year. It was about this time of the year, or maybe a little later, in November perhaps, and for a week the wind had whistled thru the wires overhead in a perfect gale. Sitting alone in that small cabin was not a pleasant position at any time, but in those long winter evenings the time dragged along at such a slow pace that I could almost keep track of the ticks of the station clock. Its staccato tick- tack seemed to break into the monotonous howling of the wind with almost machine gun noise at times, and together with the crackling of the wood fire, was the only thing that kept me from going mad with the desolation of the place.

Suddenly I Thought I Heard a Rustle at the "On this particular evening, the wind Door. seemed Then Came a Shrill Cry Again -This Time unusually strong and to get away from the Operating Table. from the repeated sound of ship reports roller" and at each lurch of the vessel, the and storm warnings that came to my youthful wireless operator longed for the ears phantoms could be seen flitting past the thru the receivers, and the wailing of porthole thru which Boyd gazed so intently. end of the watch that he might be relieved the gale overhead, I took down a from duty. The screeching of the wind book Around the small cabin the gale seemed to from the shelf and began to read. Of all concentrate its fury, and at each gust the outside and the pitch of the steamer was the books I should not have found was beginning to tell on his sensitive and a men unconsciously moved closer together copy of Poe's stories, but this was the first tho the cold of getting nervous nature, and it was with a sigh of that came to my hand. Reading Poe as the deck were relief that he welcomed the second mate was into their bones. never very soothing to my nerves, and to- "By the time I had found my place in to the small radio cabin. Toward midnight night I seemed unable to get away from the gale seemed to have reached its height Poe," resumed Miggsby, "all of my former the thrall of the stories. Hour after hour nervous strain had come back. My nerves -at least young Boyd was unable to think I absorbed the weird, the fantastic, and of anything worse -and both men were the were keyed to the top notch, and at times horrible until my head was a great whirl I think I almost trembled sheer fright. silent as the minutes hastened on toward of unsightly shapes, of melancholy with the end of the watch. Soon Miggsby, the sounds, I got along to the place where the pen- and grewsome sights. At last I began the dulum is air much like senior operator, appeared saying that it was third or fourth story, 'The Pit whistling thru the quite impossible to sleep owing to the con- and the the wind outside, when suddenly I felt Pendulum,' I believe, when I noticed that that someone was on the step outside. tinued roll of the ship, and the three it was time to send the press reports. officers decided to sit out the storm. Whether I had heard something, or wheth- "Laying aside the book I started on the er it was a sort of intuition. I don't know, With the addition of the mate and the nightly schedule of news items, First the conversation began to smack off in some but as the seconds past I became certain measure regaining my composure and ac- that the outer step was occupied. And I the usual seaman's comparisons and relat- customed state of mind, steadied ing of experiences. The mate told of a little was just as certain that my unseen, un- by the rythmical sending and the close at- known visitor was trying to get into my storms that fairly froze Boyd's blood, and tention I paid to the manuscript Miggsby, not to be outdone, answered in before station. The hair .along the back of my me. The half hour that was consumed in neck felt as tho there were thousands of kind and Boyd's hair rose on end accord- sending out this material was relief ingly. The small gale through which the a from tiny electric needles jabbing my skin. A the enormities which had been flowing into cold shiver went up my back; my heart Rollybelle was then plunging was, of my head, but from the very start course, only a capful of wind compared of the seemed to freeze. But try as I did my eyes press I noticed that it was mostly about a would not leave that book. I sat there for with some the mate had weathered, and murder the first radio man also had a few ex- that had been committed near an hour it seemed, staring with unseeing periences of his own. Haversook, the railroad station from which eyes at the closely printed page before me I came each evening. trying to figure it all out. In my imagina- Miggsby was the mystery on board the When I finally finished the sending, I could not throw off tion I thought of the pendulum with its ship. Why he -a man of forty -odd years unceasing oscillation, and the painful tick- -should still be serving on the Lakes as thoughts of that terrible affair, and invol- untarily I glanced around me when I again ing of the clock served to emphasize my operator of the Rollybelle, was unknown. feeling of dread. Then suddenly I thought Many were the speculations concerning picked up the book of Poe. I remember quite of that murder at Haversook, and of the Miggsby aboard the steamer, many were distinctly looking out of the small murderer still at large. the unasked questions concerning the rea- window near the table, but of course at "To say that I was frightened is putting son he should be using his experience and that time of night nothing could be seen it mildly. It was not mere fright that crept education in the manner he was. The except the intermittent flashing of the thru my body with all the stealth of a mur- other operator was young, on his first ship lonely lighthouse far out derer It was not a none on the spit. I did stalking his victim. in fact, and the stormy weather was not expect to see anything, but the fact mere feeling of uneasiness, nor was it the too pleasant for him. He longed for other that there was nothing cold of the gale getting into my body. It occupations that were more soothing to to be seen reassured me in no small measure. The murder was something, nameless, indescribable. A the nerves, occupations on land where one vague dread, a horrible fear, a senseless was certain of his footing at least. story, however, kept coming back to my mind as I went back feeling that something terrible was impend- Talk of storm and gale palled on the to 'The Pit and the ing. It is beyond me to tell you just what man after a time, however, and for some Pendulum'." was the matter. I cannot express the ex- minutes nothing was heard in the small At this point in the story Miggsby (Continued on page 387)

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 361 RADIO DIGEST MOTOR GENERATOR FOR tances have been bridge and messages from tor of resistance is very low, the impedance VACUUM TUBE WORK. Eilvese have been received in Honolulu. predominating. In this method the pri- The relative strength of signals received mary oscillation circuit is tuned to the The greatest drawback to the use of in America from Eilvese and Nauen were, wave desired, using inductance and capacity vacuum tube transmitters long distance for under the same conditions, 21.6 X 10' and values as desired, it being considered that has been the difficulty in getting a work 14.4 X 10-' amp. from Elek- it is always desirable on short wavelengths voltage -Abstracted high- direct -current generator. A trot, Zeits., May, 1919. to use as much capacity as possible in motor generator set operating on 110 volts order to utilize fully the 1 kilowatt power a.c. or d.c. has been brought out by a well input allowed by law. The inductance known radio company. VARIATION IN DIRECTION OF PROPAGATION OF LONG should not, however, be cut down to less This set gives 200 to 500 volts at 0.2 am- than one turn, in favor of increased ca- pere. At a speed of 1,750 r.p.m. the 48 com- ELECTROMAGNETIC WAVES. pacity. mutator segments of the generator give a After tuning the primary, the secondary By LIEUT.-Coss. TAYLOR, U.S.N.R.F. smooth current from which the ripples can or antenna circuit should be resonated in be taken out with a small iron core choke This paper is the report of the outcome the usual manner. and shunt condenser. of a study of the properties of an ex- The variable core choke coil 'should now The voltage is regulated by a separate tremely long -wave direction -finder coil, be connected in series with the transformer rheostat, making it possible to control the with a view to determining the feasibility primary and a wattmeter, voltmeter and input to the tubes and to obtain the proper of using such long -wave direction finders ammeter connected in the circuit. A power operating potential. Motor and generator, on large aircraft on long flights, such as, factor meter may be substituted for the connected by a flexible coupling, are for instance, a transatlantic flight. The voltmeter and ammeter if available. Ad- mounted on a heavy wooden base ap- use of direction finders for aircraft hav- justment should now be made of the choke proximately 19 in. long by 9 in. wide. ing been carried to such a very satisfac- coil core, until the power factor is at its Rubber feet on the base absorb any vibra- tory conclusion at the Naval Air Station, greatest value as shown by the formula tion. Hampton Roads, Va., on a wavelength of W Now that power tubes are available, a 2,500 m., it seemed highly desirable to f = number of undampt wave telegraph and ascertain if it might be possible to utilize EI telephone sets have been erected, and for airplane direction -finder work existing where W = input in watts, E = voltage, others are under way. In some cases audio high -power stations in Europe in case of I = current and f = power factor. -Ab- frequency modulation is used because of extremely long flights. Since all of the stracted from December Q. S. T. the difficulty in heterodyning 200 -meter un- transatlantic stations which may be con- dampt waves. This can be done without sidered to be really high -power stations any trouble, however, with a rotary tone operate on continuous waves of lengths DEVELOPMENT OF LOOP AERIAL condenser at the receiving station. A corn- between 8,000 and 20,000 m., it was decided FOR SUBMARINE RADIO ing article will describe the construction to build a direction -finder coil at the Naval COMMUNICATION. and use of the tone condenser. Abstracted Aircraft Radio Laboratory, Bureau of By J. A. WILLOUGHBY and P. D. Lowell. from December Everyday Engineering. Standards, of suitable dimensions for in- In the close 1917, in the course stallation in a type F -5 -L, type H -16, or of of experiments made with the object of de- THE MEASUREMENT OF ALTER- type NC flying boat. In the process this study veloping apparatus for the detection of NATING CURRENT WAVES of comparison submarines, found was made of the relative accuracy of set- it was that radio sig- WITH THE BRAUN TUBE. nals could be tings obtainable with the two -coil maximum received by means of a loop, By E. Lima. either in air or submerged in fresh water. method and the usual single-coil minimum The method. was noticed loop aerial arrangement, as finally per- This book contains a description of a It that there were fected, very considerable variations in consisted of two insulated wires novel application of the Braun Cathode- the appar- earthed at the extreme ent bearing of the Naval Radio Station at ends of the hull of ray tube to the delineation of alternating a submarine, New Brunswick, N. J. -From carried over suitable supports current waves. Instead of the usual method Scientific to the bridge, and thence to receiving Paper, No. 353, Bureau of the in which the curve of the waveform is di- Standards. and transmitting apparatus. Communica- rectly delineated upon the fluorescent tion at sea can be carried on under all con- beam screen of the tube, the cathode -ray RADIO COMMUNICATION WITH ditions more efficiently with such a loop is employed to ionize the space between the ANTENNA AND COIL AERIALS. than with ordinary elevated aerials. Also plates of a small condenser mounted on it does not nterfere with submergence. the end of the usual tube. The beam is The Bureau of Standards, Washington, D. C., have With the submarine submerged any North caused to rotate in a conical path by elec- been conducting an extensive research on radio transmission with vari- American or European station could be re- tromagnetic deflection, so that the Instant ceived as distinctly as on the surface. To of ionization with respect to the position ous types of aerials. As a result of this is receive short waves it is necessary that the in the cycle can be controlled at will by work it possible to determine by simple calculation the distance at which a given top of the loop should be near the surface rotating the deflecting coils around the of the water, whereas a wave of 10,000 tube. The condenser plates take the place receiving aerial will receive signals from any transmitting aerial when the current meters length can be received with the top of the contact -maker in the delineation of of the loop submerged 21 feet. Signals the waveform by the "Joubert" contact, in the transmitting aerial, its dimensions and the distance between the stations are could be transmitted from the loop a dis- point -by -point method. Examples of curves tance of 10 or 12 miles with the submarine are givèn in the paper. A modified method known. The small coil aerial has many ad- is completely submerged. The range falls to is, for fre- vantages, but usually not as powerful a is also described, and suitable transmitting two or three miles with the top of the loop quencies up to several million per second. and receiving device as the - antenna type of aerial. It may, however. 8 feet to 9 feet below the surface, using Abstracted from the Jahrbuch der Draht- 952 meters wavelength. Submergence of losen Telegraphic. have so much lower resistance than the antenna that it is equal to it in transmit- the submarine during reception or trans- ting and receiving value. It is shown that mission does not alter the wavelength. RADIO STATION OF EILVESE. a special type of antenna, consisting of two With the submarine on the surface a transmission range of at least 100 miles can be By S. M. SORENSEN. large metal plates, has certain advantages. The fundamental principles of design of obtained with a 1 k. w. spark set even under An illustrated article describing the wire- radio aerials have been developed. The in- very stormy conditions. The loop can also less station of Eilvese Hanover which is vestigation has opened up a large and most be used as a direction finder.- .-lbstractcd equipt with Goldschmidt generators. Com- interesting field for further research and from the Physical Review, August, 101Q. parisons are made between the results ob- progress in the utilization of radio waves. Nauen. The tained at this station and at -Scientific Paper of the Bureau of Stand- DETERMINATION OF THE OUT- Eilvese equipment is cheaper in installation ards, No. 354. PUT CHARACTERISTICS OF and in running cost and has an antenna ELECTRON TUBE only 250 in. high. The economic operation TRANSMITTER RESONANCE. results from the high efficiency of the ap- GENERATORS. paratus and the method of sending by In a brief manner R. I -I. G. Mathews ex- By LEWIS M. Hutt., of of the generator, so plains the importance resonance change excitation of be- General expressions are derived for the machines run light during the tween the primary power circuit and the that the power and current output in pauses between the signs. It is a great primary oscillating circuit. One of the ternis of advantage that the Goldschmidt system methods of obtaining this resonance is de- static characteristics of a generating tube. produces waves with practically no har- scribed as follows: A primary choke coil and are corroborated by experimental re- monics. It has been found possible to in- having an adjustable core is used. In mak- sults, obtained with a particular tuhe.- crease the power of the station by running ing up such a coil, care should be taken Scientific Paper. Bureau of Standards No. several generators in parallel. Great dis- to use sufficiently heavy wire that the fac- 355.

www.americanradiohistory.com 362 RADIO AMATEUR NEWS January, 1920

HIS department is open to all readers. It matters not whether subscribers or not. All photos are judged for best arrangement and efficiency of the apparatus, neatness of connections and general n ppearance. In order to increase the Interest In this department, we T make it a rule not to publish photographs of stations unaccompan led by a picture of the owner. We prefer dark photos to light ones. The prize winning pictures must be on prints not smaller than 5 x 7 ". We cannot reproduce pictures smaller than 31/2 x 3W'. All pictures must bear name and address written in ink on the back. A letter of not less than 100 words giving full description of the station, aerial equipment. etc., must accompany the pictures. PRIZES: One first monthly prize of $5.00. All other pictures publisht will be paid for at the rate of $2.00.

V. G. Mathison's Station HIS station is with the tuner prim- located on ary. Upon this cab- T Unga Island inet is the audion (one of the Shu- panel. The tall box magin Islands), in the center has Alaska. There be- three variable con- ing no regular com- densers and a switch mercial or n a.v a I for changing from station on the island, short to long waves the station is at and vice versa. The present operating cabinet to the left under a limited contains the long - commercial license, wave inductances. enabling communi- A one -half inch cation with Alaskan coil may be seen on naval stations. Its the left hand end of call letters are KVI. the desk, which also The apparatus gets its current shown in the photo from the storage is all my own handi- batteries. Using this work with the ex- spark coil on the ception of the panel aerial described be-. on the lower right. low I have regularly The set is, of course, worked ships as far' designed for both as twenty -five miles. dampt and undampt The is Ever Hear KV17 Here Is the Station and Its Owner, V. G. Mathison, Who Captures the aerial of wave reception, and First Prize of $5.00 This Month. four bronze wires; has a tuning capac- 350 feet long and ity of more than 20,000 meters. loading coil for waves up 1800 meters, over 100 feet high and gives excellent re- The lower right -hand cabinet contains and also an aerial condenser with master sults. V. G. MATHISON, a very efficient receiving transformer and switch for switching it in shunt or series Haywood, Calif. Frederick J. Rumford's Station I have been a constant reader of RADIO reception of European messages. Within AMATEUR NEWS and Electrical Experi- the cabinet are 4 crystal detectors which I menter since their first issues, and have can connect in conjunction with the coupler been much interested in your various con- and loading coil for the reception of mes- tests for amateurs. sages within a certain aera. I have a 180 I have an outdoor 4 wire antenna 100 degree scale in front for indicating the feet long, wires spaced two feet apart. I turning of the secondary on the vario- have also a direction finder and loop aer- meter. All of the instruments Includ- ial which is shown at the left of picture. ing storage battery and cabinet are of my I can use either aerial by the throwing In of a switch. To the extreme left is my own manufacture. the receiving cabinet portable testing outfit, which is capable of I have a small circuit breaker to protect testing low and high tension circuits; also, the audio -tron from being burnt out. radio circuits of all descriptions. The re- FREDERICK J. RUMFORD, Fred. J. Rumford Is a Close Second. Note ceiving cabinet to the right I use for the the Up -to -Date Loop Antenna. 26 Dore Street, Boston, Mass. E. F. Schwach's Station Here is a description of my whole set: tery on right side and necessary telephone From left to right are my Audions- jacks for detector, amplifier and extra pair detector and amplifier; next two knobs con- of phones. trolling primary and secondary of 20,000 me- In front of my cabinet are two pairs of ter inductance, five taps on each then phones, Brandes and Baldwin. comes my loose coupler for short wave To the right is a 1 k.w. open core trans- work, two knobs with 23 taps, tens and former, a "Thordarson" rotary, a Mur- units, on primary, and the two white scales dock sending and receiving switch and are variable condensers, primary and grid ; in. contacts and in is my arc and Bunnell key with A between condensers spark back my is a Tungar rectifier and switch, and just below that is a 90° De of set Forest condenser. In my secondary circuit a 6-60 -AH storage battery for my audions. 'Small, Compact, Vet Efficient" Was E. F. E. F. below are two bakelite 18 point switches Schwach's Motto When He Designed His Samna!, for secondary of loose coupler and B bat- Receiving Station. Chicago, Ill.

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS 363

EXPERIMENTAL SCIENCE AND POLYTECHNIC RADIO CLUB RADIO CLUB OF HARTFORD RADIO CLUB. On Sept. 8th, 1919, the Polytechnic Radio A meeting of the Radio Club of Hart- The distance is 6,000 miles to Pearl Club of San Francisco was organized and ford, Conn., was held recently in the room Harbor, yet the Radio Molecules who at present has a membership of thirty -five. of the Automobile Club of Hartford. Mr. vibrate in the rarified ozone of room 204 Meetings are held every Friday evening Kenneth B. Warner, editor of "Q. S. T." declare they have heard the ukeleles strum- at 8 p. in. in the Polytechnic High School and secretary of the American Radio Re- ming on the beaches lay League, w a s of Hawaii through present and gave a their audions, con- very interesting densers and phones a n d instructive which a r e strung talk on "Practical thicker than morn- Applications o f ing glories over the the Audion". Mr. front porch in the Warner told summer time. Look- something of the ing eastward to the theory of the Au- sea they have cap- dion and then tured messages showed some of from the Presi- the best circuits dent's ferryboat, the for detector, os- George Washing- cillator, and am- toit. They have plifier use. It was heard from New a l s o explained Orleans and An- why a highly ex- napolis. D tir i n g hausted bulb was State Fair Week, more suitable for when the club oper- an amplifier than ated under a special f o r a detector. license f rom the This was the sec- Central Department ond meeting since at Chicago, I l l . , the war. It was their messages were decided to hold heard on the Cana- the next meeting dian border and let- Members of the Exper ¡mental Science and Rade rtbh listening to a Lecture by a Prominen some time in Jan- ters were received Radio Instructor. uary, t h e secre- from other ama- tary to send no- teurs over the State. Mr. Robert Hall. a building. The following officers wer tices to the members when the date for former instructor at Harvard, gives reg t- elected: C. R. Tinsley, President, Lee that meeting was decided upon. A large lar lectures before the club. Mr. Hall owns Brillhart, Treasurer, and Herbert Dodge. attendance is expected at the next meeting a 1 k.w. transmitter which has been heard Secretary. at which time a number of radio operators 1,200 miles away. Cyril Otterholm receive. Three w ho have been in the service either at home committees were appointed -Elec- or messages every evening from the Atlantic trical Committee, Library Committee and abroad. will tell of their experiences. coast. The ban on sending was lifted re- 111.tiTL, Nn STEELE, on a Meetings and Papers Committee. The cently. Already Walter Kannenberg Electrical Committee has Secretary. Thomas Street has established communi- direct charge of cation with the station at the Y. The chief the apparatus of the club, conducts all ex- operator of the club, Mr. James Schultz, periments, and gives code tests at every SECOND DISTRICT WIRELESS has been appointed district superintendent meeting. The Library Committee keeps ASSOCIATION. for Southern Minnesota for the H. R. R. L. on file all the latest radio magazines and All communications should be addrest to news of interest to the club. The Meetings Notice to Second District Amateurs. The Second District Wireless Assn. Mr. C. J. Otterholm, Y. M. C. A., Experi- and Papers Committee arranges the pro - which was organized in 1915 is mental Science and Radio Club, St. Paul, gram for the meetings and secures speakers. now open Minn. for membership. All amateurs of the Sec- An initiation fee of seventy -five cents ond Radio District are requested to join. has adopted RADIO -SCIENCE CLUB OF been and the monthly dues of Our yearly call book containing names, ad- FOSTORIA. the organizaiton are twenty -five cents. To dresses, call letters and power of station become a member of the club one must at- of all our members will go to press in of Fostoria. The Radio- Science Club tend the Polytechnic Highs School or be- February or March -join now. Ohio, was recently organized under the Address all communications to Joseph supervision of Mr. Lutz, High School In- long to the alumni. A sample of the membership card decided upon at a recent meet- E. Engstrom, 100 St. Marks Place, Brook- structor of Physics and Chemistry. The lyn. N. Y. purpose is to study radio and scientific sub- ing is reproduced herewith. Communica- Pjects. Officers were elected which include: tions from other clubs would he greatly resident, Francis Colligan ; Secretary and appreciated and should be addressed to the Treasurer, Marjorie Newhouse, and the secretary, Herbert W. Dodge, 1038 Ortega CENTRAL RADIO CLUB. Historian, Le Roy Wolfe. St., San Francisco, Cal. The organization of the Central Radio It is the duty of the Historian to keep Club was completed recently, with the a record of the talks and experiments that drawing up of the constitution. by -laws are given each week. THIS CERTIFIE THAT and the election of the following officers A program committee is responsible for President, Louis R. Helwig ; secretary and a program including special lectures and lÌ4°. treasurer, George A. Flett. treatises upon the subjects under discussion. The club is composed of members of Each of the twenty -two members are ex- IS A MEMBER Or THC the Central Y. M. C. A. Boys' Division, pected to cooperate with the committee in numbering at present ten; but all members original experiments and research work. Ftl(I,jlfrfplit Nubia íIIlu6 of the "Y" are eligible to join. The club The membership is limited to thirty -five AB SHOWN CV 550050 ON BACS OP CANO meets every Saturday evening at eight and but all who are interested in science are soon expects to have an efficient set in eligible to become candidates for ttdmission. 6fe1:0110.61/.SS,ss.. operation. under the care of Messrs. Poolev It is the desire of the members of the s...... and Usher of the Advisory Committee. All club to keep in communication with other communications should he addressed to radio organizations through the medium of Central Radio Club, e/o Boys' Division. RADIO AMATEUR NEWS. A Neat Little Membership Card Which the GEORGE A. Fi.Frr. MARIORIR NEWHOUSE. Sec. Members of This Club Take Pride In Showing. Sec'v & Treas.

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364 RADIO AMATEUR NEWS January, 1920

THE NOLA RADIO CLUB gether and enabling them to improve their THE PHILADELPHIA AMATEUR The Nola Radio Club organized on De- installations by contact and discussion with RADIO ASSOCIATION. cember 27th. At this meeting the follow- other amateurs. Meetings are held every The Philadelphia Amateur Radio Asso- ing officers were elected: Prof. Auguste J. Friday evening at the Y. M. C. A. and an ciation, meeting at 1611 Columbia Avenue, Tete, President; Arthur H. Kopper, Vice - address is given by some prominent wire- the second and fourth Monday of each less or electrical engineer of this city. We President ; Hubert E. de Ben, Secretary- month, has now 100 active members on its Treasurer. are desirous of getting in communication roll and we are only a few months old as Twenty members were enrolled. All with other clubs and anyone desiring to an Association. members were enthusiastic and a much communicate with the club will please write With an attendance of 79 at the last larger membership is looked forward to. the corresponding secretary, Soo, Ontario. regular meeting we were surpised with a The main object of the club is to increase DAVID S. LLOYD, visit from Lt. Mackay, Radio Officer in the interest in amateur radio communica- Secretary. charge at League Island, (N. A. I.), who tion, which seems to have been lacking in informed us that his station has no amateur the past. Several members have been do- THE LOWELL RADIO CLUB. on the Black list to date. In appreciation ing very good long distance work. These of our strict observance of the 200 meter members will help the others greatly in After two years of silence, the Lowell law and several minor rules of courtesy, improving their stations and working Radio Club renewed its activities at a post- starting January 1, 1920 at 8:45 P. M. range. war reorganization meeting held recently Philadelphia Navy Yard station will send Through the courtesy of the Nola Radio in Lincoln Hall, Lowell, Mass. The at- Amateur broadcast code messages using the School we were allowed the use of their tendance of pre -war members was aug- code employed at N. A. H. school and set. mented by a large and enthusiastic body of Officers in the club elected to serve for The station call is 5NO. Anyone hear- new members. one year are President, Dr. G. M. Chris- ing this call will greatly favor us by drop- The club which was formed some months tine; Vice -President, M. Ferris; Secretary ping a card to Nola Radio School, 134 before the war, ceased activities with the P. Hoby of 1902 N. 11th St. Interesting Charles St., New Orleans, La. placing of the ban on experimental com- programs are arranged for each meeting munication. The war record of the club HUBERT E. DE BEN, with the following technical speakers : Mr. Secretary- Treasurer. is unusual since nearly three -quarters of Stuart Ballantine, Mr. W. Benson, Mr. M. the members were connected with the radio Ferris, Mr. S. S. Harris, Mr. L. Damon, units of the army or navy, several seeing Mr. Delke, and others of prominence in SOUTH SIDE RADIO ASSOCIATION long service overseas. Philadelphia radio work. \Ve are pleased to announce that we have Prior to the war, the club had rooms in At the last meeting Mr. Cadimus, 3rd one of the largest Amateur Radio Associa- one of the downtown office buildings and District Radio Inspector, told of the De- tions in any city in the U. S. And also partment of Commerce relation to the our members are all of the live sort. Our amateur. Lt. Mackay spoke of the local President Mr. M. H. Romberg is an ex- naval station's attitude toward local Naval Radio Instructor and has been in Radio Articles in amateurs; Mr. Patterson gave drawings for the game for twelve years, and our Trea- January Issue a new coil winding machine for home use; surer Mr. D. Myers is an old time Great Mr. Harris spoke on "Fundamentals of Lakes operator. The Association has been Electrical Experimenter Alternating Current"; Mr. Benson dis- reorganized and is now known as the cussed "Is Impact Transmission Practical South Side Radio Association of Chicago. 7 h, / ,i /w ( "ouipass -how it works for Amateurs ?' Mr. Delke took up Honey Any out of town members of other organi- -by Ensign Pierre H. Bouche - Comb Coils vs. Pancake Coils; Dr. Chris- zations who wish to become connected with ron, U. S. N. R. F. tine read the club magazine. a real live radio club will do well to write Members agreed to stop sending at 10 An Oscillion Radio Telephone and US. MARKUS GREEN, P. M. so that long distance signals can be Secretary. Telegraph. heard without difficulty. New Undampt Radio Receiver. EXPERIMENTERS OF THE Rado Fog Signaling a Success - ALBANY RADIO CLUB TO IN- BRONX. The work of the Bureau of STALL RADIOPHONE Public School No. 23, of Bronx Borough, Standards. A powerful radio telephone plant will be New York City, now has a club called New 165 -foot Portable Radio Mast. erected in Albany, according to plans made "Experimenters of the Bronx ". This by the members of the Albany Wireless school has quite a large number of radio Automatic Aerial Switch, by Ern- Club. The radio operator on the destroyer "bugs" and experimenters. est Oke. which was at Albany recently sent a tele- The club was organized on Nov. 6, 1919. phone call to all radio operators in Albany All those boys present who qualified were to attend the club meetings, which take admitted as charter members. Officers ,,,, ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1,,.,,,,,,,.,,,,, place in the Young Men's Christian Asso- were not elected at the first meeting, but was planning the installation of a modern ciation the first and third Tuesday of each one of the instructors of the school told month. The plan met with such success the boys how to proceed set. These quarters have been resumed and with the club's the club will erect an aerial and install ap- that the club has arranged for the tele- affairs. paratus shortly. phone's erection in the Y. M. C. A. The Club's Aerial is 125 Code practice for the jun- to be feet long ior members is The following officers have been elected: and 70 feet high. A set now already in operation and being con- theory lectures in President, E. C. Fashodt; vice -president, structed by members consists a large are preparation. of Correspondence with other clubs is in- W. Stein, and secretary and treasurer, K. B. loose -coupler, phones, detector and con - Hoffman. denser. Other instruments will be added vited and should be addressed to Lowell needed. Radio Club, Odd Fellows Building, Low- as ell, Mass. The club holds its meetings in the school AMATEUR RADIO CLUB OF every Wednesday. Success to RADIO AMATEUR NEws! BALTIMORE W. H. CARNEY, Secretary. A new organization which is expected to bring together all of the amateur radio BLOOMINGTON H. S. RADIO YATES RADIO CLUB operators of this city, and which will be CLUB. A radio club has been formed in Penn known as the Amateur Radio Club of Balti- We have recently organized a radio club Yan called the "Yates Radio Club." more, was formed on October 25. The at Bloomington High School, Bloomington, We started to organize about December purposes of the club are to bring the radio Ill. The name of the club is Bloomington 1st and already have ten members. The amateurs of Baltimore and vicinity into High School Radio Club. purpose of this club is, to study wireless closer relationship, so that their individual The club was organized with twenty - telegraphy and telephony and other experiences and experiments may be dis - three charter members. The purpose of branches of the electrical field. cusst for the advancement of the science the club is to create more interest in Radio. We have a complete transmitting and of radio, to instruct all amateurs in the Any member of the high school is eligible receiving station. We can pick up Euro- observance of the rules set for them by the to the club whether or not he has a sta- pean stations with the receiver and can United States Government, and to reduce tion. We are putting up a large set at the cover 50 miles with the transmitter. It questionable radio methods to a minimum: school. is hoped that in the near future a I KW Rules and regulations for the guidance of VICTOR R. SLEETER, transmitter will be installed. The call of the club have been adopted and monthly Secretary. the station where the club meetings are business meetings will be held. held is 8FN. The station has been licensed Since the government takes particular in- since October 1st. We already take all the terest in assisting amateur radio clubs, it ALGOMA RADIO CLÙB leading wireless magazines. Address all is contended by those back of the local The Algoma Radio Club was formed communications to William C. Babcock. organization that all who affiliate will have about three months ago for the purpose of WILLIAM C. BABCOCK, access to valuable information which they binding the amateurs of this district to- Secretary. otherwise could not obtain.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 365

Junior Radio Course THE previous lessons have clearly heated it passes off into vapor, so with but keep it going at the same speed and shown that radio impulses are propa- waves; they also have their distinct char- the same height of swing. gated in the form of waves, likewise acteristics, relative to their shapes. So in radio, we can have waves which we explained the meaning of wave- They do not change physically as the are constantly being generated, and which length. In this lesson we will take water does, but nevertheless vapor is waves will continue to come on and on, into consideration the various forms of water, and a wave is a wave, altho its one right after the other with exact pre- waves. shape and movement may be different. cision, just as the pendulum in the clock, By forms we mean the shape of the Starting with the undampt wave form, or as the waves in the water. 1 let us first see what the meaning of undampt is. Supposing we were to return 11 to the pool of water so often described in our previous chapters and procure a large '%2Q-9Q9pp. number of marbles of the same size, shape and weight. By means of an incline, see o0 Fig. 1, we now dtop one of these marbles into the pool of water and immediately a set of ripples, or waves is set up from the oI center point, where this marble was dropt. Damp/ Each wave now forms a complete circle Warr Undomp/ and the number of these circles resulting n'ove directly from the dropping of the marbles 0 into the water, we shall call a train of waves. In other words, the entire number r\f\: /\/. !v\iVNL\ of waves set up by the dropping of one Jnl marble into the water constitutes the wave train. Supposing now, that we could accurately and with precision drop one marble after so that the second c another into the water marble will start its series of waves im- mnediately after the first wave (formed by Fig. 2 -A Marble Dropt in the Water as Fig. 1 -By Dropping Marbles at Rapid and Shown Creates a Dampt Wave. Equal Intervals Undampt Waves Are the previous marble) has gone thru one Produced. up and one down motion. The second wave now sets up its series of trains as well. We Supposing now that we were to fill water in exactly the where the waves as they move along. Supposing we drop a third and a fourth, into the bottom of this bell jar same position as before, and we will find clock is still going, its pendulum swinging could take a photograph of them, we would after another will con- with absolute freedom of motion. see that they are similar to water waves. that one wave train along tinue to go out from the starting, point The water coming into this jar will now We are now going to deal with the various inasmuch as can and do as- without decreasing in height, have a retarding effect on the pendulum. forms which these waves is by a marble of exactly it, the pendulum grad- sume. Just as water assumes various each wave formed It will tend to stop size and weight as its prede- ually decreasing its steady to and fro mo- i forms, as when frozen it becomes ice, when the same cessor. See Fig. 1. These waves continue to come on, and on, as long as we do not t'/ecfcica/ Undompt Wows cease dropping marbles into the water. In fiéd-r,^/. Alma/ other words, we are constantly supplying nyres energy, which causes these waves to be formed continuously. There is nothing to hinder them, and hence they are undampt. The word undampt itself means - not checked, not deadened. Anything which lias a tendency to check may be called a damper. Thus we know that as long as we have a constant source of energy coming in at distinct intervals, the waves will go on interruptedly, one forming its movement exactly in line and in step so to speak, with the one proceeding. Let us remember now that the waves are being formed one right after the other by the constant dropping of the marbles into the water, each one, of course, making its own wave train, but each train exactly in step and coming close upon the one which lias just left. These are then undampt waves. Suppose we take another example. We have a clock. unmounted with just its pendulum hanging down and swinging freely. ()ver it we place a large glass bell jar. The pendulum will be seen to continually '.way on and on, as long as the clock is wound up. In other words, we are con - ,tantly supplying energy to prevent that /VUUV pendulum from ceasing its undulations. U,h'/t77t'd/ Wow. Undanp/ Phis energy is being applied at the critical moment, so that it will not hi any way Fig. 4 --Here the Pendulum Is Retarded or t la. 'I - A Pendulum Covered by a Bell Jar as the pendulum, Dampt by the Water In the Jar. Shown Swings Freely, retard the movements of

www.americanradiohistory.com 366 RADIO AMATEUR NEWS January, 1920

tion, finally stopping entirely. We start smaller, the same as the movements of the he resistance is mainly in the circuit just the pendulum once more, under the same pendulum died down when the water as the pendulum movement was stopt in conditions, and it gradually ceases its reached it, and it had to buck against a the jar by the water. oscillations again. The water friction is resistance. We have now what is known too great to allow a free motion of the as a dampt effect. There is nothing to QUESTIONS FOR THIS LESSON. pendulum which will always tend to stop. continue the waves one after the other. It restrains the movements and hence They are given a start, only to die out Question 1 -What is the meaning of wave dampens the vibrations of the pendulum. shortly. form? 1 he water, it will be observed, is the re- Exactly so with radio. In dampt wave Question 2 -How does an undampt wave sistance offered to the swinging pendulum. formation the wave is given a full start, look? Let us again repair to the pool of water but it meets with resistance and inasmuch Question 3 -Give a similar instance of un- and discontinue the dropping of the marbles as there is not enough energy being supplied dampt wave formation by some simple with the regularity which we used in the to overcome this constant resistance, it physical principle. first experiment. This time we only drop loses out and gradually dies away, to be Question 4 -What is meant by undampt one pellet into the water; a train of waves replaced a little later by another wave. wave in radio? is set up and it dies out. We drop another This, of course, takes place at remarkable Question 5 -How does a dampt wave dif- and note the same results. This time the velocity, one wave coming closely upon the fer from an undampt wave in (1) its waves have been dampt by the action of other, but still its characteristic is the same form, (2) its constancy of vibration? action the gravity, the cohesive of water, as the example quoted above. In a future Question 6- Illustrate the formation of a. or anything else which you might believe chapter we will take up the resistance dampt wave by a simple mechanical ex- to be the cause. Nevertheless, the waves which a wave meets with, in discussing the periment. do die out, becoming gradually smaller and differences again briefly, under spark gaps. Question 7 -What causes damping? Facts About the Bordeaux Station

Within six months France will possess a western front news from this station's mes- the Eiffel Tower and three times as great as wireless station capable of sending messages which were picked up in Shanghai, the Lyon station. Fully 500 kilowatts will sages everywhere on the world's 'surface. and there given to the local papers. be available. This will be far the greatest This station, now nearing completiotl at The Bordeaux station has been jointly electrical force ever devoted to the launch- Bordeaux, will have sufficient power to constructed by Americans and French. ing of wireless news. reach all stations within a radius of ap- When General Pershing arrived in France The famous German station at Nauen, proximately 13,000 miles. he requested a station which would enable heretofore the most powerful in Europe. The Eiffel Tower station and the im- him to keep in touch with the United States will be greatly outdistanced, both in send- mense government station at Lyon have at all times, regardless of bad atmospheric ing distance and in daily capacity. The been France's important stations thruout conditions. The Bordeaux site was im- Bordeaux station will be able to send fifty the war. The Eiffel Tower was able to mediately suggested by the French govern- words per minute, or a total of 72,000 per send messages up to a distance of 3,500 ment and work begun under the direction day. The great capacity will be made pos- miles, while the new station at Lyon had of General Ferrie of the French telegraphic sible by the employment of special equip- an average range of about 7,000 miles. service. Nearly 1,000 French and Amer- ment heretofore confined to wire tele- An average of 10,000 words per day have ican soldiers were assigned to the task of graphy. been sent out from Lyon thruout the war. constructing the immense station. Sixty men will be needed to maintain It was from this station that many parts In actual electrical power supplied the and operate the station. They will work of the world were kept informed of the antenna the capacity of the Bordeaux in four shifts, keeping open a continuous war's progress, even the far east getting its equipment will be five times as great as twenty-four hour service. Junior Constructor

SIMPLE CRYSTAL DETECTOR. Mount the condenser on a suitable base as Here is a small wireless detector which shown in the diagram. I made of very little material. Procure a Poriab/e Condenser Condensers of this sort may be mounted cup from an old dry cell, two brass main cabinets as per illustration. When corn - chine screws and a battery binding post. Brass tapir paper xi/n pleted, this makes a very efficient instru- A heavy magazine clasp with the long end Can, sirop tinfoil under ment. bent into the shape of a tube is fastened Contributed by in a hole %" in diameter drilled in the VICTOR R. SLEETER. base. The knob is an old auto switch plug key. A piece of copper wire is then soldered to the shank of the knob. Refer to the drawing for other details. This de- TO MOUNT COILS ON A PANEL. tector was made for use with Galena. Here is a simple way to mount coils on Contributed by HARRY WARDRUM. a panel. A piece of square or round brass tub-

Note the Simple Construction of This Vari- able Condenser. A Method Is Also Shown for Mounting on a Panel.

ment very similar but much cheaper and easier to construct. I have tried it out and it "does the work." First procure a tin can about 2" by 4" and a glass bottle to slide in and out of it easily. The bottle should be about 6" long. Solder a wire to the end of the can as in A. This goes to one binding post. Prepare the bottle as follows: Shellac the Colis Mounted In this Manner add to the A Crystal Detector Permitting Ease of bottle to within 2" of the mouth, and wrap Efficiency of a Receiving Set. Adjustment May Be Constructed as Shown. one layer of tinfoil around. To the tinfoil Note the Use of the Magazine Clasp. at the upper end, solder a piece of No. 24 insulated copper wire. This should be ing is used to hold the coil away from VARI- about two ft. long. From the tinfoil bring the panel and when the machine screw is EASILY CONSTRUCTED it around the curve at the top of the bottle tightened up the coil will be held very ABLE CONDENSER. and bind it at the neck. Make a spiral of rigid. Coils mounted on panels in this In a late issue of RADIO AMATEUR NEWS, the remainder of the wire. The end of this manner are very efficient. I saw an article on the construction of vari- wire goes to the other post. Cover the Contributed by able condensers. I have made an instru- tinfoil with one layer of Empire cloth. STUART Al HENDRICK.

www.americanradiohistory.com !1 January, 1920 RADIO AMATEUR NEWS 367

A SHORT GROUND. A NOVEL SPARK GAP. armature does not stick. Also fasten a In order that amateurs living in the coun- piece of platenoid on the razor blade. try or outlying parts of the city and not This can be taken from an old bell arma- having access to water pipe to ground their ture. receiving and transmitting sets, the follow- The blade should be very stiff, and when ing short ground was designed. The writer the whole is assembled and connected to a installed and found it practical and further- battery, a fine high pitched sound is pro- more it was passed by the Massachusetts duced. State Board of Fire Underwriters. Contributed by This ground consists of a short piece of JOSEPH SAMUELOWITZ. pipe five or six foot in length and three - qùarters or one inch in diameter. Thread both ends of the pipe; on one end a pipe AN EMERGENCY VARIABLE cap should be screwed on securely, first CONDENSER. white -leading the threads. The pipe should I-Iave you ever wanted a variable con- then be filled with water within three -quar- denser "imejatly" if not sooner? The ter inch from end; sealing wax to be author has and this is his solution to the melted and poured in open end of pipe. A Couple of Zincs, a Wooden Block With a Few Holes in It and You Have a Neat and Simple Spark Gap. Here is a drawing of a spark gap which has given very good service, and cost almost nothing to make. The drawing explains itself so further details are necessary. A and B are made of hard wood which has been dipped in boiling parf line. D is a hole 34" in diameter. C C are battery zinc electrodes secured from old batteries. Two small set screws E screwed in from Mil ri =MA the top hold the electrodes in place. Con- =NI ow nections with the electrodes are made as elms, itil shown. 111111111MI Contributed by FREDERICK H. GRAENING. GLASS SWITCH KNOB. A glass drawer knob is procured at a A Make -shift Variable A hardware store. The blade is made from Condenser. Try This Ground If You Have No Access to brass and is 2 in. x 311 in. It is made in a Water Pipe. It Is Practical and Should the usual shape. problem. Take a quart fruit jar, fill it Give Good Results. half full of salt water and fit a wooden cover to it. Then fasten to a block of Then screw pipe cap on the open end. The wood some thin metal strips as shown in short ground is now ready for use. sketch. Also fasten to this block a large The ground wire must be no smaller than wire to act as a support. When this is No. 6 insulated wire, to be fastened to mast completed the "plates" are dipped in shel- or building with petticoat insulators. After lac or paraffin. This coating acts as an running ground wire to place of ground, insulation and dielectric. A small hole is solder the wire to a ground clamp and se- bored in the cover to pass the wire thru. curely fasten ground clamp to pipe already A spring binding post is slipt on the wire made. A trench must be dug in earth two to make connection with the plates and to foot deep and long enough to take pipe, hold them at the desired depth. Another the pipe to be placed in trench and cov- wire is immersed in the liquid to make ered with earth and tamped down. the other connection. Lowering or raising This ground saves the amateur the the plates changes the condenser capacity. trouble and expense of running wire to the Contributed by E. D. PAPKEE. nearest pond or creek. A Type of Switch Using a Glass Knob. .Contributed by RALPH G. DICKIE. The contact points are 22 caliber rifle A SAFETY PIN DETECTOR shells. The diagram The following is a description of an ex- A SIMPLE DETECTOR. explains other features. ceedingly Contributed by EUGENE M. RIEL. simple detector: HIGH FREQUENCY BUZZER

Perhaps one has noticed on the market . the various high priced buzzers. They all

work with a steel reed as an armature in- A stead of a soft iron one. It is difficult to get a suitable piece of thin steel and the razor blade shown in illustration provides c an excellent substitute. The magnet is wound with a No. 32 wire, 8 and the base is made of wood or bakelite. The razor blade is held in place by the piece of brass bent in the shape of A in the illustration. Two screws hold the A Real Silicon Detector, Using a Safety Pin This Amateur Designed a Detector so That blade tightly. for Simplicity. the Pressure on the Crystal Is Controlled by a Wire and Thumb- Screw. Solder a piece of nickel to the pole of the magnet facing the armature, so the A is the metal end of a cartridge fuse, B a strip of mica 1/16 around the cup. C This is a detector suitable for the bug a strip of brass forming a ring over the who lacks the tools required for making mica and tightly clampt by E, D one lead most detectors. A is a piece of flexible soldered to cup, E a binding post holding B is brass strip screwed to the base C. the C and safety pin, F a safety pin and I. a adjusting wire soldered to A and running piece of silicon. thru the hole E and fastened to the screw Contributed D. by HARRY ROSENBERi.. (Editor's Note. -Try the base of a broken By turning the screw D it pulls the wire, electric light in place of the cartridge fuse thus pulling down the strip A and adjust- end. Fasten the brass strip ing the catwhisker on the mineral. near the top A Razor Blade Used as the Armature Causes so that the whole may be screwed into a Contributed by H. RICHARDSON. This Buzzer to Give a High Frequency Tone. lamp socket.)

www.americanradiohistory.com 368 RADIO AMATEUR NEWS January, 1920

RADS PÀTIÎiTS

Directive Sending System method depends upon the fact that Wireless Transmission of Energy There is provided an antenna con- impressed taming adjustable and (No. 1,301,644, issued to O. E. an electromotive force (No. 1,315,197, issued to Earl C. inductance upon the input circuit of a thermio- Hanson.) capacity and two local oscillating cir. Buckley.) nic amplifier of the "audion' type cuits of substantially identical ar- The object of this invention is to produces an apparent change in the This invention relates to the rangement; each of these circuits secure a of radiant energy from impedance of its output circuit; in transmission of energy by means of contains an oscillation generator, particular, a change in electromotive like the well -known vacuum valve force impressed upon the input cir- adjusted to generate high frequency, cuit, resulting from a change in sustained oscillations, above audibili- impedance in a local circuit asso- ty; these two circuits are so adjusted ciated with said input circuit, causes as to avoid establishing by their the impedance of the output circuit characteristic frequency a conjoint of the amplifier to vary in such a note, that is, any note due to their way as to produce therein much coupled co- operation upon a third greater changes in power than take circuit coupled with said two local place in the above mentioned local circuits. This third local circuit circuit. The thermionic amplifier in includes means for tuning and is this case acts as a magnifying device tuned to a lower frequency than for changes of power in the local that characteristic of either of said circuit, and on account of this prop- first named local circuits. erty a primary source of modulated power, capable of handling only a small amount of power, may be used to produce much larger changes, for Are Transmitting System example, in a transmitting antenna. (No. 1,309,778 issued to O. C. Roos.) In the systems which are en- ergized by substantially continuous Vacuum Tube Repeater oscillations such as those developed (No. 1,313,406 issued to R. C. by an oscillating -arc circuit oscilla- )Bathes.) tions developed in the antenna are generally not simple harmonic but This invention provides a method consist of a fundamental and vari- and means for maintaining the ous multiples thereof the higher of potential of the grid or control which if reinforced by antenna electrode which is momentarily resonance are generally of consid. negative at a relatively high value electro-static and electromagnetic induction with- erable amplitude. the transmitting station principally thus compensating for the lowered from place to place The existence of these higher out the use of or con - in certain definite directions. This potential of the control electrode wires other harmonics imposes a limitation to which is positive. ducting members. It differs essen. efficient selective transmission and object is occomplisbt by making tially from previous attempts at such use of the fact that a number of This object is attained in the it is therefore the main object of form of the invention shown herein, transmission in that it employs waves to provide means for sources of wave radiation, spaced at audio the this invention equally a oscil- by coupling the control electrodes frequency rather than absorbing the higher harmonics so along line and all common type of waves which are lating with the same constant fre - to the source of received impulses that the transmitted electromagnetic tend to produce by by means of two separate trans- of radio frequency. The audio fre- be simple quency, inter- quency electro- static and electro- waves will substantially ference a flow of energy principally formers non- industively related to harmonic. A further object of the magnetic waves are those a in one or more definite directions. each other. having invention is to provide means for The power radiated, instead of being frequency within the range of the approximately uniformly distributed human ear, this frequency being in direction, as in the case of a below ten thousand cycles per single source of radiation, will be second. concentrated in certain definite directions. Apparatus for Eliminating Static In order that the novelty of this Effects invention may be appreciated, it is necessary to point out that a (No. 1,306,170, issued to E. E. number of independent oscillating Butcher.) antenna, not controlled from one This invention comprises the use source of power and not otherwise of an antenna circuit containing ad- connected with one another, cannot justable inductance and capacity; be maintained in synchronism and two local oscillating circuits each in phase.. Further, it is not prac- containing adjustable means for tically possible to supply with power causing said circuits to generate or from one central source a number exhibit high frequency oscillations, rectifying such higher harmonics of antennae separated by the dis- means for associating said circuits Radiosignaling and for ut lining the energy of the tances here contemplated, for that System with a third circuit containing ad- resulting unidirectional impulses to would involve transmission of high (No. 1,304,296, issued to Charles justable inductance and capacity; assist the main current in feeding frequency power of large amount Le G. Fortescue.) and a receiving device, like a re- the arc. over a distance of several miles. It is recognized that, to render ceiving telephone; adjusting or the receiving apparatus of a radio system most effective, the impulses Translating Circuits Radio Transmission impressed upon the receiving circuit (No. 1,312,433 issued to John R. should occur at the rate of approxi- Carson.) mately 1,000 impulses per second, of its which corresponds to the frequency This invention has for one objects the provision of a translating or pitch of a tone of good audibility. An arrangement in which there is no object of this invention is to circuit as dis- provide means for accomplishing the input or controlling aforementioned tinguished from the output or con- results, whereby the of the radiations that are only slightly trolled circuit functions damped two circuits being combined in a may emanate from the single operating circuit associated antenna of a wireless sending station. At with the translating device. An- the same time, the wave of the invention is to trains projected into space be other object may produce a translating arrangement produced at a high rate and uni. form frequency in of this character which may be order to insure used either for modulating high the production of a uniformly pitched frequency oscillations in accordance and audible note in a distant with signal variations, or for detect- receiving station. The inventor ac- signals imposed upon high complishes these results without ing the using frequency carrier oscillations, by the a high -frequency alternator of the modulated oscil- hut by employing the usual Hertzian interaction oscillator. lations with a local source of oscil. lotions in accordance with the heterodyne or homodyne principle of receiving. (No. 1301525 issued to H. J. tuning said two local circuits to fre- Van Der Bi I.) quencies above audibility and re- This invention provides a method spectively different, and said third in which it is not necessary that circuit to a frequency lower than the primary source of modulating that characteristic of either the an- waves shall handle directly all the tenna circuit or the two local cir- modulated power required to be cuits referred to and within the radiated from the antenna. This range of audibility.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 369

%0.N.r\ll'L\WLl4Il\RL\WL\WLl%ll $100 RADIOPHONE PRIZE CONTEST ONE of the most disap- Now, the Publishers believe RULES OF THE PRIZE CONTEST. pointing features of in the truly wonderful future of The set to be described may be Radio Amateur Prog- the Radio Telephone. They will of the vacuum tube type, the arc ress at present is the stake their reputation -nay, if type, the quenched or other seeming lack of in- necessary their all-on their spark type. Or it may have em- terest in the Radiophone. conviction. They will spare no bodied in it new features not The Editor of this publica- expense, leave no stone unknown at present. The impor- tion has always taken the stand turned, to make American Radio tant part is that the set must that the ultimate goal for all ra- Amateurism one of the world's have been actually built, that it dio enthusiasts Ices, without a greatest institutions. And Ra- either is in use now or has been shade of doubt. in radio tele- dio Amateur Telephony will be in use. "Ideas" or patent de- phony. the keystone to this edifice. are strictly excluded Pub- scriptions The reasons are so obvious With this in mind the from this contest. It is also bring out the best and so convincing ; while not one lishers wish to that, insofar as this con- of our amateurs, obvious single argument can be found from the ranks test is conducted chiefly to bring against it. Radio telephony is the best being of course radio instru- out NEW ideas, commercial ra- the one and only solution out of telephone transmitting now sold modern radio re- dio telephone outfits as all the many Radio amateur's ments. Any makers, are excluded is capable of receiving by several troubles, to wit : ceiver from the contest. Telephony, inter- either radio telegraph or radio With Radio what ference with Government and 'phone messages. We are con- It is necessary to state Commercial stations is prac- cerned here, only with the instru- instruments are used, and if cer- tically done away with at one ments that send the messages. tain instruments have been Consequently and logic- The Publishers therefore offer bought, the make must be stated. stroke. of the ally, the radio amateur will at prizes of $100 in gold for the The transmitting distance in a safe and dig- best articles on a practical radio radio -phone should be given, i. e. once be placed with nified position. He will not be telephone outfit. America's the record distance covered in the past and pres- foremost radio experts will act the set. A complete diagram of bothered as in ent with anti -amateur legislation. as judges of this contest. As connections, neatly executed radio amateurism every one of the judges will ink, is to be furnished. A good But American than will surely perish if its future pass upon the manuscripts sub- photograph (not smaller rests upon radio telegraphy. mitted there can be little doubt 5 x 7 ) giving at least two views Radio Telephony no of the set is necessary. A photo- With .,;. nt:a::, is required. codes need be mastered. You graph of the builder The sizes and the kind of wire talk, that's all. PRIZES OF $100 Radio Telephony, the used in the construction must be With IN GOLD length of time required to send given, as well as the dimensions a message is from 1 /10 to 1/20 First Prize $50.00 of the principal parts. More shorter. Consequently more 25.00 than one outfit may be entered Second Prize is traffic can go on for a given time 15.00 by a contestant. The contest Third Prize .. open to every one (radio clubs than now. Prize 10.00 Vlrith Radio Telephony, the Fourth included) except manufacturers of wireless apparatus. The tuning is infinitely sharper and sfrir'i _...... ii@r%si7r%i\1frd.Irrleti better, consequently less inter- manuscript should not be longer ference. With Radio Telephony, that all contestants will be than 1,500 words. 1,000 words radio amateurism will become treated fair and impartial. Fur- are preferred. All prizes will be truly great -of a national scope. thermore, we feel certain that paid upon publication. Where there is one radio ama- this contest will not only bring The contest closes in New teur telegrapher today, one hun- out the very best there is in the April 12th, and the first but that it York dred will grow in his stead the American amateur, prize -winning article will ap- tele- will lift the new art to an un- moment practical radio pear in May, 1920. phony is here. Everyone will known and undreamt of level. use the radiophone! The far- Here are the men who will Address all manuscripts, mer, the business man, country act as the judges of the contest. photos, etc., to "Editor Radio- folks, motorboats, autos, etc., etc. A distinguished array of the best phone Prize Contest," care of Now the curious and surpris- radio talent in America: this publication. ing thing is that the radiophone Dr. Lee de Forest, Ph.D., Inventor In connection with the above con- has been with us for some years of the Audion. test, it grieves us to announce that past. There is nothing new Dr. Greenleaf W. Pickard, Inventor our second $100 Radio Prize Con- about it, no secrets, no patents of the Crystal Detector. test : "An /deal Sending Outfit," was amateur. Dr. Louis Cohen, Ph.D., Radio Ex- abandoned for the reason that of the that need bother any Inventor. manuscripts received, none we use this won- pert and several Then why don't Fritz Lowenstein, Radio Expert. complied with the most important invention to the very rule, viz., the actual building of the derful H. W. Secor, Assoc. I. R. E., Asso- limit. It will surely boom Ra- Experi- outfit, and its proof -the required ciate Editor, Electrical manu- dio Amateurism more than any menter. photograph of the set. The scripts were therefore returned to one thing in this world ever can H. Gernaback, Editor, Electrical Ex- and Radio Amateur the respective authors. or will. We have all the tools, perimenter The Publishers. so where is the hitch? News.

::c -.:w:------_

www.americanradiohistory.com 370 RADiO AMATEUR NEWS January, 1920 VJWTa D wkNÇIP Ao:

THIS n Department is conducted for the benefit of our Radio Expert menter. of all, but we can only publish such matter of sufficient We shall be glad to answer here questions 1. This Department interest to all. for the beneft cannot answer more than three questions for each 2. Only one side of the sheet should be written upon; correspondent. penciled mntter. all matter should be typewritten or else written In ink. No attention paid to 3. Sketches, diagrams, etc., must be on separate sheets. This Deepartment 4. Our Editors will be glad to answer any letter at does not answer questions by mall free work, intricate calculations, the rate of 25c quaion If. however, questions of charge. patent research, etc., a special charge will be entail considerable research OS Informed as to the price charge. made. Before we answer such questions, correspondents You will do the will Editors a personal favor If you make your letter as brief as possible. +...11.m...... l.i....m,...... n.m...... ,,,,,... .,...... ,.....,..,.,.,,,,.,,.,,..,,.. W.,.,...,.,...,. TIKKER FOR UNDAMPT WAVES, nary audio- frequency transformer which A. 2. No. The restrictions are (109) C. L. Kesley, Missouri Valley, are sold in the market at the present time. the total based on Ia., wavelength of the oscillation in- asks: Q. 3. Where could I obtain Radio Pam- ductance, lead -in Q. 1. Will and the antenna. you please describe a tikker phlet No. 40, U. S. Signal Corps, from Q. 3. Could used as a which I use the undampt trans- detector? the article was taken? mitter described in A. 1. your October issue of A type tikker which may be very A. 3. This book may be obtained from RADIO AMATEUR easily constructed by the Bureau News, page 162 with the an amateur is shown of Standards, Washington, D. C. aerial described in question, in the diagram. The method for connect- Price 55 cts. and remain TICKLER 9ni/Sh fine insufetri CIRCUIT. fi s, 'f/ Pee/ firm " (112) Maurice K. Bretzfelder, New III wire York, N. Y., asks: 1. Q. Will coils L4 and L3 in Figure 1 act as a regenerative coupler and will this circuit receive dampt and undampt waves? A. 1. Yes, this is the ordinary regenerative circuit. Mt) Q. 2. Will the circuit shown in Figure 2 (the Ultra- Audion circuit) receive undampt waves? .íaAO// kHl! [p/ß¢/' 0 /09, A. 2. Yes. Q. 3. Please give data for coils L3 and -7MRSmiller The Tikker Used as a Detector for the IA in Reception of Undampt Waves. The Metal Figure 1. Ring and Motor Shaft Are Not Insulated. A. 3. \ \'ind 40 turns of No. 28 CC wire 0 /h7 into a coil 3" 'diameter. Make another A Radiophone Transmitter ing same in a circuit coil Hook-Up In is also shown. This in the same manner and connect them as Which an Ordinary Loose Coupler Is Used. form of detector is adjusted by thè speed shown in the diagram. Lay one on top of within the government limit of restriction? of the motor, and by the pressure of the the other on the table. If wire on the disc. they are to be A. 3. Yes, by inserting a condenser in mounted in a cabinet, arrange so series Q. 2. Would one of these that the with the primary of the oscillation be of help to coupling may be varied by the turning of transformer and the amateurs out here where we hear NAA a knob. antenna or ground. and coast stations all night, yet cannot hear LOOP AERIAL TRANSMISSION. them in day time using galena? GOVERNMENT RESTRICTIONS. A. 2. The (114) Dorris L. Sargent, Harrisburg, tikker is a very sensitive (113) Ill., form of detector, and you should Irwin P. Stephens, St. Charles, asks the following: be able Mo., desires 1. to hear NAA and all other to know: Q. Can I use No. 14, bare, aluminum undampt sta- Q. 1. What aerial tions within range very readily. would be the natural wave- in making a loop aerial? If so, would length of an aerial composed of five wires, it require more or less turns of wire? eighty feet long, fifty A. 1 Yes, 14 RADIOPHONE HOOK -UP. feet high, fifty foot No. bare wire may be used. lead -in, wires spaced one foot apart. The same number of turns will be satis- (110) Fernando A. Wessell, 300 Broad A. 1. 300 meters. factory. Street, Red Bank, N. J., asks: Q. 2. Are the restrictions of the govern- Q. 2. Can one send with a loop aerial? Q. 1. Would you kindly give me a hook- ment on sending stations based on the na- A. 2. Transmission has been success- up for sending wireless telephone with an tural wavelength? fully accomplished with a audion loop aerial. bulb? Q. 3. How many miles and how many A. 1. The hook -up is herewith given. meters should be able to receive using the Q. 2. How to make an audion bulb out following: a six of volt carbon filament bulb, and Six foot square, loop aerial with 20 turns, where can such a bulb be bought. No. 14 bare aluminum wire, single A. 2. slide The November issue of RADIO tuning coil 11 inches long, 3% inches in AMATEUR NEWS contains information re- diameter, galena detector, fixed condenser garding the experimental audion bulb, con- 1/20 M.F.D. cap and double pole seventy- structed from a small six volt bulb. This five ohm receiver arranged as in Fig. 1, type of bulb may be obtained at almost enclosed. any automobile supply house. A. 3. You will probably have very little success using a loop with the instruments USE OF GRID BATTERY. you mention. An audion detector and a (111) K. Gerdin, Floral Park, N. Y., one or two step amplifier are necessary for wants to know: even fair results. Q. 1. In your July issue you published in the "Radio Digest," a diagram for aud- SPACING -OF WIRES. ion amplification before the signals reach (115) M. M. Mitchell, Ravenna, Ohio, the audibility circuit. Kindly inform me wants to know: of the use of the grid battery. Q. 1. On page 62 in the August RADIO A. 1. The grid battery is used in this AMATEUR News there is a table of the spac- circuit to impress a positive charge upon ing in inches of the loop aerial, the way it the grid. This tends to render the tube says is 1 -9 inches and 1-4 inches, etc. Does operative for amplification. this mean of an inch and t/q of an inch Q. 2. Please give me data concerning or does it mean 1 to 8 inches? the construction of coil M which induces A. 1. This was due to the printer's error current into circuit L C. The Tickler and the Ultra.Audlon Circuits and should read one -quarter inches, seven Both Permit the Reception of Undampt sixteenths, etc. A. 2. The coils M consists of an 'ordi- Waves. (Continued on page 388)

j www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 371 MURD CK No. 55 RADIO RECEIVERS

2000 OHM 3000 OHM COMPLETE COMPLETE DOUBLE SET DOUBLE SET $5.50

MURDOCK APPARATUS combines the desirable qualities of good design, excellent materials, and efficient operation to an un- Variable Condenser No. usually high degree. 368, .0005 mfd. $3.75 Variable Condenser No. Moreover, it is priced so rea- 366. .001 mfd. $4.75 sonably that it gives the ex- the "most for his perimenter ¡ :' money." \,1in >1 I A copy of our latest bulletin / ,` will be sent free to those inter- Fixed Condenser, No. a58 Receiving Transformer No. 344 $0.70 ested in good apparatus. $9.00 WM. J. MURDOCK COMPANY 50 Carter Street 509 Mission Street CHELSEA, MASS. SAN FRANCISCO

Yon benefit by mentioning the "Radio Anmteu News" tchen writing to advertisers.

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372 RADIO AMATEUR NEWS January, 1920 LEARN THE Static Elimination AUTOMOBILE by Directional Reception BUSINESS By GREENLEAF W. PICKARD Great orpnr lunllhs for Iratied men of Aloha Lewis. S h o p Foremen. Licensed (Continued from page 34) Chauffeurs, or In MlalMAI for yourself. WEof expensive wireless ul stru- plie,. tc.. $CAN diam.) copper wire, with the turns spaced fora selapparatus.i ouse hold article that goes like wild- apart 30 cm. This loop was in the form of a fire because it is M°h° necessity a genuine Y long and because it sells You low rectangle, 30 meters long, and 6 cheap. no learn here by putting on overalls and All of our premiums doing the actual work, under expert tuttrue- meters high, the lower are guaranteed part of the loop be- fact. new and per. tnrs. By this method You, cannot fall. If We give you no junk. you ing about 4 meters from the ground. Plans to have yearned for a future ahem you can The receive high grade wuele,, make big money-lime it is. plane of this loop was approximately apparatus without costing north- should melt' you a cent Write TODAY for information east portunity interest you. An op- by southwest, that is, it was in the such u this one again be may never great circle bearing placed before you so take BUFFALO AUTO SCHOOL of the more important advice grab It, our European uosi. purchm Dept. 86 Buffalo, N. Y. stations. This coil aerial was houoi Ìd tuned to >rleof twisty fl :eeenr:h. low the desired wavelength by series tb y ar. Ir,..btibl. act,at r hi n' stinetivene..,th.lr 7Telr splendid vats.and inductance L. and capacity C, a fixed coil unerslnseand their quick tilling lities ill mute them L. calms (hi. article la go like hot of 22 millihenrys being used in most of s genuine necessity in alum GLIDE "O" PLANE the work, The open antenna of this combi- R dn. apre, ferbe1l nY is the.,is the .n after them.ut d ,o't nation consisted of the conductor of the to pay vela.sold. écdon't 'i Learn the cent r i loop itself and a connection to earth addles. and we , of at G ourreataelou, will -'. ''P,í%fr ^". principles premium i Aviation by by way of a coupling coil Lt of 22 milli- ppaidfrom. twelve household './ ua information for tellline. _., flying o u r cry i ne,m arné the ale,tuns etc. -m, I,, goods can famous glide postalhnd loaren the lrestt us O plane. Not vú:tu.Op C BECK NOVELTY HOUSE 1298 Carroll etructted gliding model, which may Street, Brooklyn, N. Y. be thrown by hand on the field or launched from the top of the The ORIGINAL ' bill. Will circle, loop and glide

, , ,1 gracefully with a light throw. Constructed of best materials, AUDIOTRON finished In Bright colors with the Insignia I of the U. S. Army on the Main Plane. Very durable and easy to fly. All wood, ad- ADAPTOR justable. Price 55e Postpaid In U. S. Send for catalogue 53. HEC Aeroplane Co., 345 E. 49th Si, New Yerk City $1.75 Each Shipping Weight One Pound - -- LOOP CURRENT Your Tubular Bulb will - - QUADRATURE now fit the standard "VTer RESULTANT socket with our adaptor 2 C Bain 4ln..I1 In, between renter.. 17 is total Ìulagth. Shipping weight I3I6a, Bib New Type "VT" Socket of lathe is machined. W orkmanshpip fret - with chuck. Now $1.00 Each Canbe fitteduwÌW á In plate sod d1 .Ì I1 .p. i equipment. Order one tod.ay Yriee 16.00 cub Our adaptor :deer. consists of a standard base with SYPHER MFG. CO.. DEPT E TOLEOO,oKIg nickeled brass pillars appropriately placed to ac- commodate five leads and support tube. Pillars are forced Into solid bakelite, not sealing wax. We have PARAGON ß back-mounted rheostats, $1.75 I New radio UKULELE call book out Jan. 15, '20, $1.00 each If elnonudnt.drenuvn.w.n.mmrlc crud nth° n.ulua> l2. evnrr.; tree unarm.l20 RADIO EQUIPMENT CO. simple toucan.; ggive WOOo tree tI( roe - ,yt 630 WASHINGTON ST. BOSTON, MASS. Ìmw.ä undtostory- YY, n troa, A.k e. to cane inn awry orlit norst Youwllll?.""L M- obagadon- absolubly (roes No CENTRAL RADIO ENGINEERING CO. jS) The Hawaüanlostituteof Music + ° - =- 604 W. 60th Street, 1400nroadwaL.mpt. 13A Naavork Chicago, Ill. ACROMATIC TELE'SCOPE n WS AT YOU WANT LIMITED OFFER

on au i_.. ! LONG 199(,EN¡s MARS 'oR RANCn ' -/ I 3500 METER Made upon new +dcntlac principles. with nicely brassbound powerful lenses, edentllieally ground- Travelers, hunters, farmers, boy moot. and everyone leseope. llave needs a te- Loose Coupler you over enjoyed the marvels of a telo- $8.50 scoped Each telescope gttarantund just as represented, or money promptly refunded. Bend e9 cents to-day. Highly finished in golden oak or mahogany EASTERN NOVELTY CO., Sop,. 177 E, d3 Rt.,New York Slider adjustment on Primary and Ten Tap Switch on Secondary. SBe FREE from 22" Long 7" Wide 71/2' High TAMMERIN Send 2e Stamp for our Bulletin A. HOME COURSE. Physical Culture mcth..d. strengthen the voice organs. Simple exercr..., The Radio Engineering Company form the habit of easy, correct speech. Results GUARANTEED or NO PAY. Write for full MANUFACTURERS OF particulars. IT CAN BE DONE AT HOME. Sutherland Scheel, Educational Bide., 70 5th Av.. N.Y. AMATEURS RECEIVING OUTFITS AND INSTRUMENTS "RaDIO APPARATUS" Complete Tuning Coil Receiving Sot $4.00 Beg to announce their reorganization and the opening of a show room and distribution center FOR THE Send stamp for descriptivo literature SOUTH, of all standard radio apparatus. MAYMIN RADIO MFG. CO. The famous 1845 E. Twelfth S Brooklyn, N. Y. "RECO" KEY reduced for a short time to $6.50. 81x cents in stamp will bring our new and revised catalog now on the press. -LOWEST PRICES Note New Address: CAMERAS Supplies and printing at reduced 827 Madison Ave., Baltimore, Md. mi.. Eliminate the middlmnan. FIB. CALL 3 EM Deal direct and .are 010110 Catalog 22 the Degeneration of the Ideal Figure -of -Eight Reception Curve Into Pool Photo Place. 640 E. Clementine St., Philadelphia, Ps. Insure your copy reaching you promtlyp each menth. I an-Showing Hour -Glass Shaped Figure. Subscribe to RADIO AMATEUR NEWS-S1.50 Year. You by benefit mentioning the "Radio Amateur News" when writing to advertisers.

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS 373

A 240 Spark Note on 60 Cycles with three to four times the energy in your antenna and with a low decrement entirely inside government regulations -all possible with the "AMRAD" QUENCHED GAP Our bulletin No. 12 sent on request explains $17.50 Altho within the reach of every amateur's means, this GAP is on par in performance with the finest commer- Folder giving com- cial quenched gap. Not only does it increase the efficiency of your station three to four times, but is p le t e specifications economical to use because it can be operated without sent on request. a motor generator and also because it effects a saving in current. Ask your dealer today to show you the AMRAD Quenched Gap. If he does not have it, order direct from us but send us his name

(I Keep out Makes DC like AC For the amateur who operates of trouble where AC is not available the You can meas- "AMRAD" ure your wave INDUCTION COIL length with ab- $28.50 solute accuracy Works as consistently as a trans- and no difficulty former with the Adapted for amateur use from the designs for the army signal corps coil, the AMRAD induction coil entirely overcomes difficulties "AMRAD" found in all other WAVE METER coils. $5. A special model is made for use with 32 In this very simple and reliable volt farm lighting device a flashlight bulb and direct outfits. reading dial give instantaneous and precise measurement of your Ask your dealer to en- s h o w y o u t h e transmitting wave. It does A MR A D induction tirely away with danger of violat- coil. ing government rules. Your dealer can supply you Folder giving complete details mailed Descriptive folder sent on request. on request

AMERICAN RADIO AND RESEARCH CORPORATION

21 PARK ROW, NEW YORK, N. Y. Laboratory and Works. Medford Hillside, Mass.

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It www.americanradiohistory.com 374 RADIO AMATEUR NEWS January, 1920

henrys inductance, a variable inductance L Make Your Own for tuning this open antenna circuit, and a variable resistance R, and was tuned to the WIRELESS APPARATUS same wave -length as the loop. The coils L, and L. were quite closely coupled to- V gether, and coil Le rather more loosely coupled to the secondary or detector circuit S. This secondary circuit, as shown in Fig. 21, employed the static coupled audion circuit due to Lieut. Eaton of the U. S. Navy. _ Two steps of audio frequency amplification were usually employed, in addition to the circuit shown, and the normal signal THE "ILLINOIS" strengths from Rome, VARIABLE CONDENSER Lyons and Carnar- Hard Rolled von were about 1,000 times audibility. The Aluminum Plates resistance Three Styles, No. 1, Panel, No. 2, Open Type R was found to be an important as shown, No. 3, Fully Encased. Anti Profiteer. element of the circuit, and in its absence Less than pre -war prices. Fully assembled and 72 the results were decidedly inferior. The tested, SAVE Sent Prepaid on Receipt It's easy to make your own at home amount of resistance required was of Price sur- Style No. 1 with the aid of these No. 2 No. 3 Money back if not setts - 4 up -to -date prisingly large, being about 3,000 ohms. 43 Plates. $3.00 $3.50 $3.75 fled. Just return conden- books that 23 you can understand. Each The operation of this circuit is sub- 2.50 3.00 3.26 ear within 10 days by m- has over 72 pages and over 60 illustra- 18 2.25 8.76 3.00 lured P. P. tions, 3 color cover, size 5 x 7 Inches. These condensers are made by a watch me- LESSONS IN WIRELESS TELEGRAPHY is chanic schooled in accurate workmanship. Per- a course in the elementary principles which sonally we will need no introduction to Amateurs you must understand to obtain good results. who have "listened In" for "time" and "weather" WIRELESS CONSTRUCTION AND INSTAL- from 9, ZS. LATION FOR BEGINNERS gives complete G. F. Johnson, 827 Black Ave., Springfield, details with working drawings for making Ill. simple but good sending and receiving apparatus and erecting aerials, etc. THE OPERATION OF WIRELESS TELE- GRAPH APPARATUS shows how to obtain best results and greatest ranges with all kinds of apparatus, how to tune the station Copper to 200 meters, use a wave meter, apply for license, etc. EXPERIMENTAL WIRELESS CONSTRUC- Aerial Wire TION gives details, with working drawings for making more elaborate and efficient send- Two Feet for One Cent ing and receiving apparatus, complete sets, etc. We are offering 100 feet of pure copper aerial 30ceach 1 wire for 50c, No. 14 the gauge -be sure to include postage postpaid 20 SET and insurance charges or wire Less than the price of one telephone re- will be shipped by express, collect. ceiver. Order now while the supply lasts. Price0 subject to change without notice. COLE & MORGAN, Inc., Pubbshers The Famous Skinderviken Transmitter Dept. 112, 19 Park Place, New York Button We are now handling this well known and efficient device and can supply the local battery, detectaphone or Radio types -postpaid for $1.00 Fig. 23. -Here the Loop Is Balanced to the each. Ground by a Three -Plate Variable Con- Below are listed a few of our New Year specials. denser. Everything You Want To Dry Cells- Slightly used test as high as 20 amperes, shipped by express collect. Only stantially as follows : As it is a develop- per dozen $1.50 Know About A. C. ment Resistance Lamps -Variable each .25 Motors of the circuit shown in Fig. 16, and Carbon Grain Transmitters consists of a combination each 1.00 of a loop and an Send 5c for our illustrated catalogue. Is found Instantly In the ELECTRICAL open antenna, with the currents added in WORKER'S FRIEND. The only complete ELECTRICAL book of its kind for the man ou the job or phase in the secondary circuit' it has a SPECIALTY CO. the student. Will make you an expert motor reception surface which is Dept. R 48 So. Front St. Columbus, O. repairman. Contains 66 electric motor draw- essentially like ings with complete Instructions for rewinding the upper half of Fig. 20, with a maximum and reconnecting. Tells how to put each coil In the sluts, how to get speed, alterna- reception only on the horizon in the directions. cycles poles, how to find the coil tion of the distant transmitter, Static pulses throw, ,umber of coils per group and number of groups, etc. from any direction other than that of the Covers all practical reconnecting changes from distant station itself are either received phase weakly or not at all if it happens to ATLANTIC RADIO CO. another. oor r changing both the obese and orig- voltage at the same time. inate to the rear of the system. Reaction Written so you will understand It. You between the open and closed circuits, with need this book -send for copy today, resultant complex wave formation, is pre- Our line of new appara- or we will ship vented by the high damping of the open $4.00 C. O. D. if you prefer circuit, which with 3,000 ohms inserted is tus comprises, t h e latest practically Free Circular aperiodic. The reason why so post -war equipment. on Request large a resistance can be used in the open circuit and still have substantial equality of Prepare your station for Henry F. Bosshart open and closed circuit current is due to P. O. Box 68, Homewood Sta., Pittsburg, Pa- the fact that a loop of the dimensions em- the new era in the amateur ployed is much less effective than an open radio world by equipping antenna of the same height at long wavelengths. The currents from the open cir- with our standard, h i g h A New cuit, reduced to the same amplitude as those grade apparatus, parts and in the loop by the inserted resistance and VACUUM RECTIFIER TUBE degree of coupling, are shifted thru 90° supplies. for Wireless Telephone a absolutely the newest device on the market. Does a way with motor generator. It per - 34 Batterymarch BOSTON mils you to use 110 VOLTS 60 CYCLES alternating current and rectifies this to di- Street MASS. rect current for the transmitting tube. r,.a o r We dari ipl ire circular 138 WIRELESS EQUIPMENT CO., INC. 19 Park l'L,

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS

The Demand for Wireless Operators Far Exceeds the Supply The New York Wireless Institute will make you an operator --AT HOME -in your spare time -quickly, easily and thoroughly. No previous training or experience required. Our Home Study Course has been prepared by Radio Experts. Experts able to impart their practical and technical knowledge to YOU in an easy to understand way. The graded lessons mailed you will prove so fascinating that you will be eager for the next one. The instruments furnished free, will make it as easy to learn the Code as it was to learn to talk. All you will have to do, is to listen. Big Salaries Travel the World Over Wireless receive excellent salaries rang- operators A Wireless Operator can visit all parts of the ing from $125 to $200 a month and it is only a world and receive fine pay and stepping stone to better positions. There is prac- maintenance at the tically no limit to your earning power. Men who same time. Do you prefer a steady position with- but yesterday were Wireless Operators are now out travel ? There are many opportunities at the holding positions as Radio Engineers, Radio In- numerous land stations or with the Commercial spectors, Radio Salesmen at salaries up to $5000 Wireless or with the Steamship Companies. a year. FREE Instruments and Text Books

We furnish free to all students, during the course, the wonderful receiving and sending set exactly as produced in Ille illustration. This set is not loaned, but given to all students completing the This wonderful Set for learning the Code furnished free with our Course Course. The Transmitter shown is the celebrated Ofnnigraph Easy Payments used by several Departments of the U. S. Govern- A small pay limit down will enroll you. We will make ment and by the leading Universities, Colleges, the payments so easy that anyone ambitious to enter the fastest growing profession- Technical and Telegraph Schools throughout the Wireless-may do so. U. S. and Canada. Start the Omnigraph, place the Send for FREE Booklet phone to your ear and this remarkable invention Without obligating you in any way, send for our book- will send you Wireless Messages, the same as let "How to Become an Expert Wireless Operator" - it is free. Mail the coupon below, or postal or letter though you were receiving them, through the air, but do it today. - from a Wireless Station hundreds of miles away. When you apply for your license, the U. S. Gov- NEW YORK WIRELESS INSTITUTE ernment will test you with the Osnnigraph -the same rDept. 41, 258 Broadway,======New York City model Otnnigraph as we furnish to our students. Ask any U. S. Radio Inspector to verify this. New York Wireless 1 Institute Dept. 41, 7E8 Bwsy, N. Y. City

FREE Post- Graduate Course 1 Send me free of charge, your booklet "Bow to Become an Ex- pert wireless Operator," containing full particulars of your Course, so desire, at A one month's Post- Graduate if you 1 Course, including your Free l.strament Offer. one of the largest Wireless Schools in N. Y. City. New York -the Wonder City -the largest port in the World Name and the Headquarters of every leading Wireless and Steam- 1 ship Company. 1 Addrens 1 1 l 'ity or Town State {,w ben,mt by menW"una Ow "Radio Amateur Nrtes" whom writing to advertisers.

www.americanradiohistory.com 376 RADIO AMATEUR NEWS January, 1920

In phase by the transfer from the open to By a Close Application of the Very the closed *cuit by way of the coupling, Best Business Methods and Our between L1 and L., and hence are added in You Benefit APPLIED PERSONAL ATTENTION" phase in the loop circuit, and then transferred, by the coupling between Ls and S, 1 to the secondary circuit. It will be seen that the change in phase accomplished in the original circuit of Fig. 16 by a Phase adjuster in the form of a variable artificial Doing The Largest the Largest Radio Supply Radio Supply Organization Business in the in the Central East Central East

I s I Flg. 25. -In This Circuit a Second Loop Al Efficient Equipment for All Is Used Closely Coupled with the Main Loop Srnd 4r. Stamp for Catalog At The Best,;Costs You Less When You Buy From line, is here done by the simple expedient Us of coupling together tuned circuits. Our 200 to 2500 meter loose coupler costs $18.00. The performance of this circuit may be You cannot buy a better instrument if you pay more. judged from a typical set of audibility Mention Radio Amateur News meter readings taken by the writer, which are tabulated below : THE RADIO APPARATUS SERVICE Time Station Loop alone Loop-i-Open "A Supply Company for the Radio Amateur" A.1a. sig. stat. sig. stat. Dept. 11.25 Nauen 2500 800 400 60 1, Room 803, Union Savings Bank Bldg. Washington, D. C. .35 5000 1500 3000 800 .45 " 3000 1000 400 120 .50 " 5000 1500 - 12.00 " 3000 1500 - - 2.35 1000 1000 250 60 .40 " 1000 20o 3.10 Carnarvon 1000 4000 600 600 .15 1500 5000 600 160 .25 800 5000 200 80 Just The Press! .30 Nauen 1000 5000 250 80 Off .35 1000 4000 600 160 " .37 Carnarvon 1000 5000 600 160 Design .41 1000 4000 500 160 and Construction .55 Nauen 1000 5000 300 80 of Audion Amplifying 4.00 600 2000 300 60 The static intensities in the above table Transformers were taken in each instance over a period of five seconds, and no attention was paid to the clicks, which were of several times Radio and Audio the intensity of the grinders. It will be Frequency Type noted that during the forenoon, with strong signals and weak static, the system had little effect. But during the afternoon, with This I a t e s t and important weaker signals and much stronger book by Mr. Ed ward T. static, the improvement in the ratio is Jones, late Associate Editor rather striking. As a matter of fact, the of Radio News, will be of circuit of Fig. 21, during periods of severe great interest to static, enabled the solid, uninterrupted all radio copying of stations which would on the amateurs thruout the land. ordinary circuits be so broken up as to be The transformers shown unreadable. in these books have never Continued use of this circuit at the Otter Cliffs station developed the fact that the been described in print earth connection of the open antenna was before, and have usually not attached symmetrically to the aerial, the been considered a manu- result being that a certain amount of cur- facturer's secret. Any- rent in the open circuit was flowing directly thru the loop and coil L,, of course 90° out one who has several of phase with the loop current. This tended vacuum tubes cannot afford to do to decrease the sharpness of the unilateral without this book because it will enable him reception, and hence the degree of static to build the necesary amplifying transformers very readily. The elimination. As this effect is often present designs are very simple and in the simple loop or coil aerial when used rugged, and anybody can make them for direction finding, it may not be out of without much trouble whatsoever. place to briefly explain it here. Mr. Jones, the author, is a practical man, who is an experi- Considering only the horizontal plane menter himself and knows whereof he speaks. The book is printed on good paper and has an attractive cover in two colors. Paper bound. Size, 5" x 7 ". Contains many illustrations, diagrams and working data necessary to build the transformers. PRICE Postpaid, 25c Experimenter Publishing Co., Book Dept. 231A Fulton St., New York, N. Y.

Add to your Salary-Make extra Pin Money Fig. 26. -The Simplest Solution and the One MONEY for YOU Start a lucrative business of your own. Which Gave the Best Results from the Com- 4and an how day taking Radio Amateur News." We'll pay you wen and you'll enjoy the bination of Vertical Open Antenna and the wort w5 intloubscr Cl ülatlot Dept., RADIO AMATEUR NEWS. 233 Fulton St., N. Y. City. Loop, Is Shown Here. You benefit by mentioning the "Radio Amateur News" when writing to advertisers.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS reception of a simple loop aerial, with a certain unbalanced capacity to ground (either by way of unbalanced leads or unsymmetrical construction of the loop itself), .,, ,s.....4. a it is obvious that the system wiU act as ,_, NEW MOTORS combination of loop and open antenna, with .r - FACTORY GUARANTEED ALL SIZES - IN ORIGINAL BOXES - the currents added together, not in phase, ,11rw but in quadrature. As a result of this, the is Bur New Guaranteed Eitel,ci' ; currents will add together irrespective of Your Opportunity Asturian of shaeut Mlaraarw<. their direction, with the result that the Gaga Men Motors Charging Generators Polyphase Motors Charging .1 Battery Outfits ideal figure -of -eight reception curve de- Oo -eel.oli. A. t' .,, I.. - a.hle for all [tabling I phew. A . r.. a o

; Battery Charging generates into an hour -glass shaped figure, Ieo R. P. NI. a,. .. 1730 RPM. rung. ' and P.,' R..luirean'in. s AI, N. r1M4 irl.o- b.. and pulley. the breadth of the neck depending upon the P -III III TOLL L C- IM ert1. 11 tons w $284.50 er.Rlaoak $16.50I,Ax.. amount of open antenna current. This de- 14 .aLL.Wtwr.. $42.50 .wwt,etdEwl $40.00 li ION- ti.. $21.001... Ill wells, LC- Ia Arm. 11 wen 50 generation is shown in four steps of in- 1/2 1wP.a II- W.&ih i.- $38.50 .a1 ..walked $68 22. P. $59.50 creasing open antenna current in Fig. 1/N. P.. BelaTOLLn «wt+i,e $24.50 IN.ni.Ib L0_1Merns 2 ww.aIww.ww $46.50 ii nth crIwtmWr.w.. $75.00 The remedy for this trouble is a simple one, ,m..1:..e $24.50 1x. r. $72.50 and consists in balancing the loop to - $67,50 1 ó...."'Z,b... «.NLL I1..e$38.50 ent`:.WH:liwon $85.00 ground, as by a three -plate variable con- axP 50 al N.P- IIslaMIT. c III reLL4C- 171..h11 rent 23. 2 ,IR.NE1r.e$3sso -' denser, in the manner shown in Fig. By raWr, daK Ire. $10850 Li T nnwl ..ndwrl $85.00 i a P. turning this loop thru 180° in its own plane, «..R.. n..e $58.50 $1 02.50 to rN4 LC. SM.wh 00 3 ,"..,:-.:."11141'.-. a w. wn mtdwr, $110 so that the terminals of the loop come out $124.50 Ili wME I11.a $58.50 t N. P- Nfl sues. I/« on top, a material advantage results in di- N P. ne111 TOLL raw m. a , $36.50 m.m u- 1M °.n. 5 wade.. dsi.l heir $ Gwmlr $85.00 :g,dE- 1Em ws, n.wE n «I ,eildNel $125.00 rection finding. As the points of highest 164.J0 potential are thus removed as far as pos- UM FOR CATALOG. IMAM: IN MOTORS END GENERATORS sible from the earth, the loop is much less SP E CIA WUN I NG MACHINEMOTOi grounded objects. m 75 affected by surrounding H. P. L al1dail 4 19'EACH 1 - Of course, this method is at its best with lw / LP, 11S1 RPM. o°".1.

www.americanradiohistory.com 378 RADIO AMATEUR NEWS January, 1920

011 the same dimensions as that of N Fig. 21) is given below: Time Station Open alone Loop alone Open r. r. sig. seat sig. stat. da. stat 1.45 Nauen 2000 4000 300 600 Hanover 300 60 WIRELESS KIEN 400 1500 100 500 200 80 2.54 400 1500 150 500 300 100 .44 Nauen 800 6000 200 500 300 80 3.10 200 800 300 800 400 80 .18 Lyons 100 1000 150 500 150 .27 40 n 200 2000 150 1000 200 60 and AMATEURS .52 300 1500 100 500 150 50 7.14 Carnarvon 300 1500 150 600 150 80 .28 400 4000 CI 300 1000 400 100 .40 400 3000 200 800 300 100 The Second Edition of the 8.26 Lyons 400 1500 150 500 300 100 .57 400 1500 200 1150 300 150 9.11 Carnarvon 100 800 100 800 150 60 .20 Lyons 600 8000 200 1500 150 100 .32 Carnarvon 7 8000 1 1000 150 100 Consolidated .37 Lyons 300 1500 100 600 100 60 One of the striking things in the above tabulation is Carnarvon at 9.32 P. M. Radio Neither on open antenna or on loop, taken singly, could sufficient signal be heard to measure on the audibility meter. But on the Call Book combined loop and open antenna, the signal was well above the static in intensity. The adjustment of the combined loop and open antenna, in either of the forms shown, is quite critical, the best unilateral Will Be Out Feb. 5 reception being when the loop and open antenna currents are equal. In Fig. 27 is shown the result of combining different The only book in print offi- ratios of open and loop current. The up- permost reception curve is the horizontal cially listing all the amateur plane characteristic of an open antenna, with no loop current. The second curve radio calls as issued by the Bureau of Commerce. represents equal amounts of open and loop Meets a timely and urgent necessity among radio current, and is a cardoid. The third figure represents the addition and steamship companies, professional and ama- of two parts of loop current to one of open, of while the fourth shows pure loop reception. teur radio operators, and those having need It will be seen that the vector O -A, in the authentic and practical information on radio calls; open antenna, in either of the forms creases uniformly as loop current is added radio, telegraph and cable rates, special signals to open current, until the ratio is one to one. Any further change in this ratio, in- and general radio procedure. creasing the proportion of loop current, decreased the vector O -A, the reception being only at a maximum when the ratio is All Amateur Calls Listed unity. Similarly, the amount of reception from the direction O -B In addition every vessel and land sta- That new and great aid to navigation decreases steadily and as loop current is added to open, being zero tion in the world is represented and -the radio compass -is explained is is a unique of this publication when the ratio unity. Any further listed alphabetically, according to feature change, increasing the ratio of loop to open, names of vessels or land which will be of special value to stations, and masters of merchant vessels. This results in increasing the amount of recep- according to call letters; Revision of book contains all calls listed in the tion from O-B. American coastal stations under U. S. new book to be published by the De- The writer here wishes to emphasize the Naval control, and their new calls. partment of Commerce. fact that the results above tabulated are in no sense exceptional for his system of the combined loop aerial and open antenna, nor were they taken under "freak" condi- Price $1.00 Prepaid tions. These combined loop and open circuits have been in daily operation, summer and winter, over a period of nearly two IMPORTANT NEW years at Otter Cliffs, and have proven con- sistent performers. During the summer of Given Free with Each Copy 1918 the Otter Cliffs station circuits gave A Wireless unbroken copying of the European stations Map of the World in colors is given absolutely free at times when all other Atlantic coast re- with each copy. This map shows the locations of all the high ceiving points were helpless. In fact, altho powered RADIO stations in the world, including the time a large amount of interesting experimental signal stations. In addition it tells at a glance how far away work was done at various points on the any of these Atlantic coast, it may now be definitely said stations are. Of greater interest are the time that the above -described circuit, in the in- zones, which enable the amateur to compute instantly the stallation at Otter Cliffs, was the only static correct time for the zone in which he is located from any time eliminator that played any part in our war signal station. use of transatlantic radio communication. An interesting and as yet unexplained matter is the marked predominance, at least on the northern Atlantic coast of static originating on the western or southwestern Order Your Copy Today horizon. In all probability, this direction Send Cash, Money Order or Check. Act quickly, as orders are of origin accounts for. some of the elimina- pouring in and the edition will be rapidly exhausted. All orders tion observed on the above circuits. The filled in the order writer also has a certain amount of evi- of their receipt and first come, first served. dence which tends to show that this effect is confined to the immediate neighborhood of the coast, and that it vanishes a short Consolidated Radio Call Book Co., Inc. distance inland. 41 Park Row, New York City As a result of the writer's study of the This book also contains the advertisements of practically every leading com- three -dimensional characteristics of various pany in the radio field. aerial combinations, many novel and useful i arrangements have resulted. While a de- igmeellsellselleas tailed showing of these arrangements will

You benefit by mentioning the "Radio Amateur New:" when writing to advertisers.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 3 79 be given in a later paper, a brief description of one of them may be of interest here. Examination of Fig. 20 will show that if this figure is turned thru 90 °, so that the vertical plane C -Z -D -N becomes the hori- D.H.E. SPECIAL zontal plane, a very favorable reception surface results. No energy would be received SOFT TONE COMFORTABLE SENSITIVE from the zenith, and but very little from the rest of the hemisphere, until the horizon was reached. Even on the horizon, reception would only be at a maximum along one 3200 OHM HEADSET $6.0 " line, and zero at right angles thereto. In order to turn the reception surface of a TEN DAYS' TRIAL circuit thru 90 °, one has only to turn the circuit itself thru this angle. In Fig. 28 is shown the circuit of Fig. 26, turned thru 90° in the plane of the loop. Examination D.H.E. Navy Coupler, $18.50 of Fig. 20 will show that the circuit of Fig. 28 eshould be placed in a vertical plane 45° D.H.E. Tuning Coils, 4.50 from the bearing of the distant station for best reception. It is best to remove this circuit somewhat from the earth's surface, WE CAN SUPPLY ALL STANDARD in order to prevent distortion of the open antenna characteristics. Ordinarily, if the RADIO APPARATUS AND PARTS FROM STOCK lower part of the loop is elevated some five or six meters from the ground there will be SERVICE AND SATISFACTION GUARANTEED. nb appreciable distortion. The writer gives below a typical extract CATALOG WILL BE OUT JAN. 1st. from the performance log of this circuit. The loop A (Fig. 28) consisted of seven turns of No. 16 B. & S. copper wire (1.3 DOUBLEDAY -HILL ELECTRIC CO. mm, diam.) spaced 10 cm. apart in a sole- 7 high RADIO noidal coil, 30 meters long, meters DEPT. 719 -21 Liberty Avenue, Pittsburgh, Pa. and with the lower conductors of the loop about 4 meters above the ground. The open horizontal antenna A, -A, consisted of a single wire 50 meters long, with a variable condenser C, inserted at its center. The LONG WAVE TUNER coils L, and L. were of 20 millihenrys each, 20,000 METER and the resistance R was 1000 ohms. Pre- Diagram on bottom, involute coils machine wound that bear liminary tests having indicated that the honeycombs. XDA comes in on tap No. 1, NSS on tap No. 4. 5 taps P &S. Tested on aerial 25 feet high, 40 feet long. All tuners weigh 2 pounds. No complicated tuning. Coils waxed in. Formica top, full nickel finish. Works through worst static. We satisfy you or return the money. 3,000 METER ARLINGTON TUNER Amplifies NAA sign 50 times. Tested on 25 foot aerial. Tested in Frisco and Davenport. Also gets all 4000 meter arc stations. 7 taps primary, 5 on tickler. Receives wireless phone call s. 200 METER REGENERATIVE TUNER Very sel.ctive and amplifies sign from 175 to 300 meters. Fine for RELAY work. Any of above tuner coils set to wax for mounting in cabinet $10.00. All complete tuners EIS each delivered to you. Tuners licensed under Marconi Patent No. 763772. KNOCKED DOWN VARIABLE CONDENSERS I plate grid variable, capoc., .00025MF $1.75 21 plate Sec. variable, capac., .0005MF 2.25 43 plate Pri. variable, copse., .001 2.75 Packed in strange box with full directions for assembling. Formica tops, hard rubber knobs complete with scale and pointer. Aluminum plates .015 thick. Agents and dealers wanted. Catalog free. TRESCO, Davenport, Iowa

When Signals are Weak Ba They can be brought in one hun,trtd times stronger if you connect into circuit a FIG. Combining Ratlos of Open and Loop Current.DDifferent

open antenna received materially less energy than the loop, the resistance R was removed from the open circuit, and placed fiEBE «AD)D in the loop. The secondary S was then coupled with L, instead of Ls, as shown in Fig. 28, and the following readings were Vacuum -Tube Detector taken: and Two -Stage Loop+ Open Audio- Frequency Amplifier Time Station Loop alone TYPE RORD sig. stat. P.M. sig. stat. Control. 50 1 It embodies tho latest development In Amplifier construction -The Grob. Automatic 2.45 Natten automatically. 1S O 600 60 A telephone Jack and plug system controls bath tho filament and telephone circuits 58 Detector only Is In use; In tho second Jack one stage of 3.14 1.y 100 500 30 With the plug In the first Jack the 1 In the third Jack the n 800 3000 200 amplification Is added and the output transferred to the telephones. .2ß Naueana stage is connected Into circuit and the complete wit is in operation. 4.12 Carnarvon 100 S00 second Amplifier .25 100 600 60 Amplifier tubes work test at a different It potential than detector tubes. Tho RORD 80 Is equipped with two sets of binding pests for 11 batterlos-une for tito Detector. tho other .32 Mitten 100 10OÓ 80 1 for the Amplifier tubes. .s8 You will got results front this Amplifier that will surprise you. In conclusion, the writer wishes to ac- Hand for tree bulletin IP110; complete catalog 10 cents. knowledge the valuable assistance and co- A. H. GREBE & CO., 72 Van Wyck Blvd., Richmond Hill, N. Y. operation of Mr. J. A. Proctor, and the aid su freely given by I1r. Alessandro Fabri, Yen beno4t by a,rnticning the "Ratio Aamtoa, Now" when n+itiag to advertisers.

www.americanradiohistory.com 380 RADIO AMATEUR NEWS January, 1920 whose helpful enthusiasm and encourage- ment will long and gratefully be remem- Radio Mesco bered. Diagrams Radio Buzzer BIBLIOGRAPHY and Formulae With Shunt Resistance- 1. S. ARRHENIUS. Roy. Soc. Proc. 73. pp. U.S. Navy and U.S. Army 496 -499, June 22, 1904. in Loose Leaf Form Standard. 2. S. CHAPMAN. Sci. Am. Supl. 2282. p. The publishers CONSOLIDATED 199, Sept. 27, 1919. RADIO CALL BOOK have ompledth preparation of diagrams and instructions 3, DEFOREST. Proc. Inst. Radio Eng. 1. 1. on:- p.p. 42 -51, Jan. 1913. Measurement of Capacity of a Condenser. (Substitution Method.) 4. H. M. AIRY. Electrician, 67. p. 29, Apr. Calibration of a Variable Condenser. Two Diagrams and 14, 1911. Curve. Measurement No. 1 5. PICKARD. Sci. of Inductance of a Coll or Circuit. Am. Supl. 1254, p. 20097, Two Methods Jan. 13, 1900. -Two Diagrams No. 2 Measurement of Distributed Capacity of an ductance. In- 6. PICKARD. U, S. Patent No. 842,910, Diagram and Curve No. 3 filed Nov. 30, 1906. Measurement of Fundamental Wavelength of an Antenna, Three Methods. Three Dia- grams No. 4 Measurement of Wavelength of Distant Trans- mitting Station. Two Methods. Calibration fhe of a Receiving Set. Two Diagrams. Radio Officers of the NC planes, after Measurement No. 5 testing all other buzzers, decided to use tb,- of Effective Antenna Capacity. "Mesco on radio Two Methods. Two Diagrams 6 their equipment. The R -84 Measurement No. stns equipped with two of them. of Inductance of Antenna and a Third Method of Why? Because of Measuring Effective Capac- Its reliability and coo ity of Antenna. One Diagram stancy in operation; greater output efficient-) No. 7 Measurement of Antenna Resistance. Substi- ease of adjustment; unaffected by extreme var. tution Method ations in weather conditions; exposed wire elimi Schematic No, 8 noted. Wiring Diagram of Regenerative Au -. dlon Receiving Set Suitable for Receiving Sparking Is almost entirely eliminated, High Power so Undamped Wave Station, Con - the energy lost in light and heat in the nections shown are those used in operation of other most Navy buzzers is here conserved and Commercial Receivers No. 50 and radiated In the form of oscillating energy. Table giving the value of LC (Product of In- This buzzer maintains a constant note and is ductance and Capacity) for wavelengths from 300 recommended as an exciter for checking ware. to 20,000 meters. Inductance In Micro - meters where pure note and ample energy are henrys No. 100 requl red. Fig. 28. Table same as above but with Inductance in -This Shows the Circuit of Flg. 26 centimeters List No. 55, Mesco Radio Buzzer. Price...52.05 Turned Thru 90' In the Plane of the Loop. No. 101 Schematic Wiring Diagram of Signal Corps Type SCR-68 Radio Telephone Transmitting We carry a very large d and complete line of standard 7. M. DIECKMANN. Luftahrt und Wis- Receiving Set No. 51 wireless apparatus and solicit your inquiries. Wireless Schematic Wiring experts In all of our stores. senschaft. 1. 1912. Diagram of Type CW-936 (Navy Submarine Chaser) Radio Telephone 8. E. THOMSON, Elec. W. & Eng. 33, pp. and Telegraph Transmitter and Receiver. Send for New 769 -770, June 3, 1899. No. 52 the Edition of Our Schematic Diagram of Type S.E. 9. S. G. BROWN. British Patent No. 14,- 1100 (Navy Catalog M 29 Flying Boat) Radio Telephone and Tele- 449 of 1899. graph Transmitter No. 53 It Is pocket else, contains 264 pages, with over 10. STONE. U. S. Patent No. 716,955, filed These diagrams and instructions are the 1.000 Illustrations. and describes In plain, clear most language all about Bells, Push Buttons. Batteries. Jan. 23, 1901. CLEAR. CONCISE. COMPREHENSIVE Telephone and Telegraph Materiel. Electric Toys, and CONVENIENT form of Instruction that Burglar and Fire Alarm Contrivances Electric 11. F. BRAUN. Electrician. 57. pp. 222-224; has ever been presented. They are printed Bells. Call Medical Batteries, Electrically Heated Apparatus, 244-248, May 25 and 1, 1906. on pages size 81/4 x I1. Battery Connector,. Switches Battery Gauges Wiretess June Telegraph Instruments, Ignition Supplies. etc. 12. R. A. WEAGANT. Proc. Inst. Radio Complete Set of 14 Sheets 17 IT MEANS MONEY SAVED TO YOU Eng. 7. 3. pp. 217 et seq., June 1919. to nave Our Catalog when you w,.nt to buy. 13. PICKARD. U. S. Patent No. 956,165, as described, sent postpaid 1 C Manhattan Electrical Supply Co., Inc. filed Sept. 3, 1907. CONSOLIDATED RADIO CALL New York: Chicago: SL Louis: 14. IBID. pp. 231 -232, BOOK 17 Park Place 114 S. Wells St. CO., Inc. 1106 l'ire St. 15. PICKARD. Elec. Rev. June 15, 1907. 41 San Frandsen Omcr: 6114 51tsslon St. Park Row, New York, N. Y. 16. PICKARD. Elec. Rev. Oct. 3, 1908. 17. PICKARD, Proc. Wireless Institute, May, 1909. 18. A. S. BLATTERMAN. Jour, Franklin VACUUM TUBE Radio Intelligence Bureau Inst. 188. 3. pp. 289 -362, Sept., 1919. CONTROL 19. E. Earn $125 to $150 per Month BELLINI & A. Tost, Elec. Eng. 2. PANEL Complete pp. 771 -775, Nov. 14, 1907. Course and Pre - 20. PICKARD. U. S. Patent 956,165, p. 5, ls. Most efficient and neatest Practice Buzzer Set W 15 paid 37-40. panel manufactured. Course prepared by a leading authority on the 21. PIcxARn. U. S. Patent Bakelite panel, graduated dials, mounted in subject. No. 876,996, All questions answered free after pur- filed June 10, 1907. oak cabinet. Variable grid condenser, rheostat, chase of course. The entire faculty is at your :end tube receptacle mounted back of panel. command to solve your problems. May be used in any circuit. Wuelen Reclmg sets: Wire - We DesignO less Transmitting sets; Wireless RADIO INTEREST IN THE - SOUTH. PRICE -less Bulb (with V.T.Baae sr sets; DngroundVatic-ground , Rogon installations, Audlotron mounting)-- 816.00 complete or individual Imtrumenu, at nominal cost. W. B. Downey, radio Build your own apparatus at one-tenth the coat. We inspector of the For Full Information write furnish dimensions. drawings, and diagram. complete, bureau of navigaton, department of com- Special Questions answered by our Query Department merce, was in DAYNOR RADIO ELECTRIC COMPANY at 25o each. U questions involve considerable research Birmingham recently on a work, ear., special charge, not to exceed $5.00. is tour of the southern Box 105 r Wilk!nsburp, Pa. made. states, in which the government is making an investigation to RADIO INTELLIGENCE BUREAU ascertain how much interest there is in this 864 Roosevelt Pl. New Orleans, Le. sèction in radio service. Mr. Downey examined a number of radio operators who had served in this branch of service during AMATEURS the late world war in the United court States Complete line of Radio Mate- IND W room at the federal building and Apparatus. TANCE PAT - found them very enthusiastic rials and all Standard WIND- TERNS over this IND SIEGERT ° °° work. have some new and inter- Only We 1250 two cities in Alabama were visited esting developments. West 97th Pl. by Mr. Downey -Mobile and Birmingham CHICAGO, ILL. -and he stated that about 100 men had Write us your needs. been examined 1 in North and South Caro- lina, Georgia, Florida and Alabama. "RADISCO AGENCY" Special Radio and Electrical There were before the war a large num- apparatus built to order ber of radio stations all over the country, K & L ELECTRIC CO. according to Mr. Downey, but during the war all of these were dismantled at the re- 427 Olive Street, McKeesport, Pa. Electrical Experimental Work quest of the government, but now all ama teur stations may be reinstated, while other BRIGHT BOY WANTED radio stations must be licensed Write for E,Nmates -1 Will Saft You Money ernment. by the gov- residing In N. Y. One that is capable of making his own He did not find as much interest radio apparatus, to make parts and assemble. Chan. to in Mobile as he expected. leant trade: write, giving age, wages expected. etc. Arnold. 2052 Lexington Ara, N. Y. Yon benefit by mentioning the "Radio Amateur News" when writing to advertiser,.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 38 I

s ,: : CONTRARY -=-= ,i;: to RUMORS ' Spread by a Competitor ,_ /I( The Radio Distributing Co. is still manufactur- ;li ing their unmounted universal wound Induc- t\j tances, and will continue to supply their agents Iw "' these very efficient coils. . "°`ems That the RADISCO COILS are superior to any

.. '. similar typeYP of inductances is the opinionP of several well known radio men who have received signals from very remote stations. The RADIO DISTRIBUTING COMPANY will assure all purchasers that they will experience no inconvenience by reason of any action now pending or to be started by reason of patent on coils purchased. These coils are in stock at all RADISCO AGENTS. RADISCO AGENTS carry only apparatus of proven merit. Look for the RADISCO trademark on all coils you buy and be sure of getting efficient apparatus. Below are listed a few of the reliable firms who carry the Universal Wound Inductances and are our Agents for all standard radio apparatus of merit. Communicate your wants to them. ALBANY, N. Y. BRONX, NEW YORK NEW ORLEANS, LA. PITTSBURG, PA. E. L. Long, CITY L. A. Rose, Radio Electric Co., 21 Magnolia Terrace Amateur Wireless Equip- 4323 Magnolia Street. 4614 Henry Street, ment Co., SCRANTON, PA. ATLANTIC CITY, N. J. 1390 Prospect Ave. NEWCASTLE, PA. Radio Mfg. Co. Independent Radio Supply, P. 0. Boa Wireless Mfg. Co. Also 118 So. New Jersey Ave. CHICAGO, ILL. 507 Florence Ave. 8 Kingsburyg y St., BEINVILLE,QUEBEC,CAN. Chicago Radio Laboratories, Jamestown, New York. Canadian Radio Mfg. Co. 1316 Carmen Ave. PHILADELPHIA, PA. SPRINGFIELD, MASS. Philadelphia School of Electric Service Co., BOSTON, MASS. McKEESPORT, PA Wireless Telegraph, 585 Armory Street. Atlantic Radio Co., K. & L Electric Co., Broad and Cherry Streets. TORONTO, ONT., CAN. 34 Batterymarch St. 427 Olive Street The Vimy Supply Co., I. BROOKLYN, N. Y. PROVIDENCE, R. 585 College Street. Keelly & Phillips NEWARK, N. J. Rhode Island Elec. Equip. WASHINGTON, D. C. Electric Co., A. H. Corwin & Co., Co., National Radio Supply Co.. 312 Flatbush Ave. 4 West Park Street. 45 Washington Street. 1405 U Street, N. W. if none of the above agencies are in your vicinity, communicate with RADIO DISTRIBUTING COMPANY, NEWARK, NEW JERSEY

Mils N. Y. ELECTRICAL SCHOOL Is the pioneer and 1 premier school of the "Learn by Doing" method. When you have completed this Course ou shall be fully m a llfled to handle ALL branches of Electrical Industry. The equipment of this School Is unequalled and up-to- the- minute. No preparation needed to become a 'learn- er" In this school. You can start to learn on any day of any week throughout the whole year. Send for catalogue. OPEN ALL SUMMER NEW YORK ELECTRICAL SCHOOL 29 -31 west 17th St. New York City

Pou beuent by mentioning the "Radio Amateur News' when writing to adrnn,.,

www.americanradiohistory.com 382 RADIO AMATEUR NEWS January. 1920

TWENTY MILLION DOLLAR RA- DIO COMPANY FORMED Ag American and international wireless operating system that is designed to link the countries of the world in exchanging 3 Inch Dial commercial messages, which is announced to begin business in the United States and throughout the Americas, Hawaii, Britain, France, the Scandinavian countries and China and Japan, has been effected through Indicator interests of the General Electric Company of Schenectady, under the name of the Radio Corporation of America. The United States corporation and a subsidiary FOR SALE operating company for general service in Central and South America will have a total capitalization of $20,000,000. The new organization is planning to co- BY ALL operate both with the Government and na- No. 66 Dial only tional commercial interests, and to meet the suggestion by Federal authòrities that Postpaid 75c American trade shall have free and inde- Radisco Agencies pendent communication with South and No. 67 Dial with Central America as well as with other for- Bakelite Knob eign and more distant trade centres. Postpaid $1.30 AND BY The Radio Corporation has been greatly strengthened through its connection with the General Electric Company, by reason of which it will have available for its use the valuable wireless apparatus recently A. H. CORWIN & CO. developed by the General Electric Com- pany, the principal device being already 4 West Park St. Newark, N. known as the Alexanderson high -frequence J. alternator. Radio stations, which the corporation is waiting for the Government to relinquish control, are the transmitting depot at New Brunswick and the receiving station at Belmar, N. J., which will be used for the British service; Marion, Mass., and Chat- You may think that ham, Cape Cod, sending and receiving for Scandinavian service, and Tuckerton, N. J., Your Transmitter is for sending and receiving from France Tuned Hawaii, Japan and China operations will But you don't know unless your station is equipped with be conducted from Balinas and Marshal, a reliable Antenna Ammeter. near San Francisco. These Roller -Smith Hot -Wire Ammeters were made for the U. S. Army Air Service for use on fighting planes. AMATEUR RADIOPHONE CON- CERTS. Regularly $13 - Listening by means of wireless telephone Our Special Price $7 to a selection of music played by a phono- With the Armistice calve a cancellation of contracts and these Ammeters, graph has become the Saturday evening which had successfully passed the exacting Government tests, were returned amusement of 400 owners of wireless re- to the manufacturers. Each is in perfect condition, packed in its original carton ceiving sets living in Pittsburgh, Pa., and and ready for immediate shipment. environs. The scale reading is: 0 -2.5 Amperes. Shunt giving double or triple this Several weeks ago Frank Conrad, who range, 75c extra. has a private laboratory at Penn avenue and Peebles street, took his By buying the entire surplus we are able phonograph to sell these Ammeters at less over to his wireless telephone transmitter, than the Government paid for them in lots of one thousand. Better order yours a record today as this may be your last chance. Remit put on and started the music. by check or money order. That started the concerts. Every Satur- A. day night since 400 ears have been glued H. GREBE & CO., 72 Van Wyck Blvd., Richmond Hill, N. Y. to wireless telephone receivers, listening to Conrad's renditions. Conrad stated that he is using four vacuum valves to transmit the music, and employs a spark transmission of 900 cycles frequency. The music is heard, it is said, in exactly This Audion Control the tones rendered by the phonograph Panel designed and record. made by Arnold, is the only one of its kind on the market at OTTER CLIFF STATION present and represents After every receiving station on the the best value of any. coast had tried to get into communication Just think of getting with Stavanger, Norway, the Otter Cliff an Oak cabinet with station of the U. S. radio service was the polished 3!t" Hard only successful one. This station is now Rubber panel front, receiving an average of 20,000 words a equipped so you can day, which is more than any three stations use a V. T. Moorhead, on the Atlantic coast are doing. It is or any type of tubu- planned to make this station the largest lar bulb, with giving and best equipped on the Atlantic coast. that youy can use either at will? A six point switch for battery control giving 16 to 40 volts? Yes, Batteries are included, best make, and a mica grid con- UNITED STATES WIRELESS denser. STATIONS. A concealed rheostat with only knob, pointer and scale showing All connections made with stranded wire, and soldered. Special posts for phone plugs, binding post The government shore wireless stations with white. connections n icely lettered on rubber and filled numbered 135 on June 30, 1918, of which Sine over all 12" by 8" by a ". Price shown 319.80. 88 were in continental United States, 20 Call and fr, ,. (WC in Alaska, 19 in the Philippines, three in J. F. ARNOLD the canal zone, two in Hawaii and one each Established 1910. 2082 LEXINGTON AVENUE, NEW YORK in Porto Rico, Guam and Samoa. The government ship stations total 470. You benefit by mentioning the "Radio Anonym, News' when ,+itiao to adoyrtior,J.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 383

Radio Telephone on Mount Hood By C. M. ALLEN (Continued from page 336) f1f of energy required when talking; only a small fraction of this energy is required for receiving. The problem of furnishing Telegraphy power for the set on top of the mountain Learn was rather a hard one on account of the (Wireless or Morse) difficulty in packing the storage batteries up and down the mountain. It is planned The EASIEST, QUICKEST, to overcome this trouble by installing a CHEAPEST WAY wind- driven motor generator charging plant on top of the mountain this year. While the details of such an oufit have not yet been worked out, the available wind AT HOME velocity records indicate that there will be ample power from this source. It is In Half the Usual Time planned to have the outfit entirely automatic in operation, with the wind motor of such size as to permit its being readily removed and stored when the station is not WITH THE OMNIGRAPH in use. On account of the high charging rate required by the Edison type of stor- "Just Listen -The Omnigraph Will do the teaching" age battery, it may be necessary to use a lead battery, altho it would not stand the The Omnigraph is an Automatic Transmitter that teaches you both rough usage as well as the Edison. In this the Wireless and Morse Codes, at home, without any expense except event it is probable that they would have of the machine itself. Merely connect to battery and your to be removed to a suitable station for the the cost winter months to prevent freezing. Wind Buzzer, or Buzzer and Head Phones, and the Omnigraph will send motor power may be used for driving unlimited messages by the hour, at any speed you desire. charging generators at lower stations also, altho it is probable that either a gasoline USED BY THE U. S. engine or water wheel will be more satis- GOVERNMENT factory. The Omnigraph is used by the It is planned to continue the tests as Government in testing all appli- long as the season will permit, with the cants applying for a Radio view of securing all of the information License. It is also used exten- possible in regard to the type of sets most sively by the large Universities, practical for Forest Service use, and dem- Colleges and Telegraph Schools onstrating their successful operation at a throughout the Country for few at least of the points where wireless teaching Wireless and Morse. is needed. Further investigations will be Hundreds of the Army's skilled made to determine the shielding effect of to operators who served during the timbered areas, high ridges, etc., and war learned with the Omnigraph. what extent tree antennae may be used, also with the view of developing a more satisfactory method of sending call sig- Let The OMNIGRAPH Teach You Wireless nals. While the tests are only about half For a few dollars you can have a complete You'll be surprised how quickly you will completed, the results obtained so far have outfit that will make you an experienced attain speed. Even if you are already an been satisfactory, as previously stated, and operator in the shortest possible time. No operator the Omnigraph will help you. It it is believed that a consideration of some hard, laborious work -just learn by listening. will make you more proficient, more accurate The Omnigraph is adjustable so you can and more confident Thonsaads of Otani. of the possibilities in connection with the start receiving messages slowly, gradually in- graphs are in use to -day and thousands of use of wireless apparatus, particularly the creasing the speed as you become proficient operators owe their success to them. telephone, is justified. At present it will as an auxiliary Write for Free Catalog probably be of most value The Omnigraph Mfg. Co., to the wire lines, in providing a reliable Send for a catalog to -day, showing the 3 dif- communication between the wire ferent models, $12.00 to $28.00. Every 39 F Cortlandt St., means of Omnigraph is sold with the absolute guarantee New York City. line centers of distribution and inaccessible that you must be satisfied or your money back points so located that the construction and for the asking. Mail the coupon today-the Gentlemen: - maintenance of wire lines is not physically catalog will come to you by return mail. As per your ad in Radio Amateur News or economically practical or possible. The please mail me your free catalog of Omnigraphs. Forest Service has spent thousands of dol- The Omnigraph Mfg. Co. telephone Name lars in the construction of some 39 F Cortlandt Street, New York City lines extending thru isolated regions, in Address dis- order to secure communication with City State tant stations, for the proper working of 0111IIIIf1111,111, 1111,01.11, 111, 1111 .11111,111,11111I11.1il.11114 the fire protective organization. In some cases these lines have to be practically re- built each year, and used only two or three months during the fire season. Event- ually the wireless telephone may take the SPECIAL $1.00 place of many of these lines, or it may connect the Forest Supervisor directly with ONLY some of the distant points on his Forest. SALE! For instance, a fire chief on the Okanogan at his desk in Postage National Forest could sit We have on extra. Okanogan and talk directly with the fore- 2,000 in hand man in charge of a fire crew on a fire C a r b o n Ship. Weight. the northwestern part of the Forest where Trans- 2 lbs. This can Grain \iJrT,c.,_ there are no wire telephone lines. miners as Diameter, be made possible thru the use of a 100 - per photo- Reduced Photograph of Trans- portable pack horse wireless mitter showing nickel plated caso 3% ins. mile range graph. They and Hard Rubber Mouthpiece telephone set that it is planned to develop. are first - It is possible, too, that the ever -present class instruments and may be used for all kind of experiments, especially for Ford may be equipt With wireless tele- wireless telephone sets, where a heavy current is to be passed through. Slightly phones, using an antenna with telescope used, but in perfect working order. Money refunded if not satisfied. A real masts, which would permit the driver on bargain. Order one or more today. patrol duty to report a fire to his chief THE ELECTRO IMPORTING CO., 231 Fulton St., NEW YORK without stopping his car, or possibly talk to an airplane doing patrol duty overhead. to advertisers. Yon benefit by tnentio,ind the "Rodio Amateur News" when avilis°

www.americanradiohistory.com 384 RADIO AMATEUR NEWS

,.,11e,,,,,e,1 ...... ,,,,,,,,,,,,,,,,.°,,,,,,,,e,e11,,,aaeee,,,,,,eaaa PLACE A NEW ORLEANS SILVELL DETECTOR SPRING An Ideal Receiving Set WIRELESS SUPPLIES AND By URBAN WORNER MINERALS on your mineral detector and note the de- OF ALL DESCRIPTIONS cided Improvement in signals received. Ad- (Continued from page Jostable to any detector. Set of six mailed 342) L. A. ROSE on receipt of $1. Satisfaction or money re- 4323 MAGNOLIA STREET funded. that they can be NEW ORLEANS. LA. E. 8. LINDMARK, heard with the phones lying on the table. It is Send 6 Cents for Catalogue 215 Avenue F, Brooklyn, N. not only on long Y. waves that this set shows such results, but also on 200 and 600 meters. Ships lying TYPE 5 -A RECEIVING $6.00 in the harbors of Tampico, Mexico, and For SET Progreso, Mexico, the beginner who wishes an efficient. perfectly balanced and very handsome receiving set at moder- are copied very often ate price. Ibis set was designed. Shore stations and ships at See come In Willi surprising clearness. Consists without difficulty. Amateurs from all over of double slide taming coll. galena detector with the Arlington tested crystal, fired condenser and country (before the war, of course) binding posts for connecting aerial, ground and have been copied with a fair degree of receivers. Mounted on beautiful hardwood bue. signal Completely connected and ready for use. strength. This set also is very sen- Prim 88.00. RUBBER KNOBS sitive to wireless telephone signals, which Large knob, 1 %' dia. with pointer, suitable for have been heard on several variable condenser, rheostat, ele., each 60e occasions. Knob and switch arm, 135" die. switch arm I operate this set purely for its scientific 156 long. salt and instructive Knob and switch arm, 1" die.. switch am value. Radio, in my opinion 114" long. each 45,. cannot be surpassed by any other science. L UNMOUNTED COILS It has itt Wound opened a new field to me, namely, 1 with No. 24 enameled wire. 12" long 4" dia. each 82.00 the experimental field. It has taught me 10' long 3" die, each $1.00 to be patient, to be careful, and to be 0" long 2% "dia. each .7s. ever Postage must be Included with all orders. watchful of how the world is steadily going MC MAHON & ST JOHN forward. Again it gives me pleasure and 86 West Ave. South Norwalk, Conn. pastime found in my own house, and I am sure there is no better place. RADIO CONTROLLED AIR TOR- WIRELESS PEDOES NEXT. AMATEURS, Aerial torpedoes in the form of pilotless DEALERS AND MANUFACTURERS ! airplanes guided by wireless will play their Have You Seen The part in the next war, members of the American Society of Mechanical Engineers "DEPENDABLE" of New York City were informed by Col- Line of Radio Instruments and Complete Sets? onel E. A. Deeds, of Dayton, O. We manufacture a This development was far advanced dur- large line of DEPENDABLE apparatus -not the cheap ing mail order variety, yet our prices are low. this war. The fuselage, laden with Tuners, Couplers, Detectors, Fixed high explosives, will drop as a plummet, and Variable Condensers, Loading Coils, etc.; also Binding Posts, Switch Levers, etc., Switch Points, hitting a target the size of a city accu- etc. rately. Send for New Catalog No. 9 to our New York office, 3Lusitenía 4Eieba[,r 19 Park Place, New Oermalt prrof f German n setiin i. York City. oink "Lualwia ". ut:Ma of ha.D t kad- DORON downfall of German Empire. Duplicates die- BROS. ELECTRICAL CO. - - - castot In metal. copper oxidized. We each: HAMILTON, OHIO. i1Jt.IÌ three for edcu .te,t.nds. Collecptors to want olne oar more. Clreuler free. C. .rMAII(ÑitD. Warren. Pa.

Distributors of all Prominent makes RADIO APPARATUS Largest and best stock of any house:In New England DE FOREST HONEYCOMB WOUND INDUCTANCE COILS Solid Wire Litz. Wire Appx. W. L. range Cat. No. Appx. Ind. with .001 Var. Cond. Price Cat. No. Price L25 .040 130 -375 $1.40 1-35 LL25 $1.40 .075 180 -515 1.45 LL35 1.45 L50 .15 240 -730 L75 1.52 LL50 1.64 .3 330-1030 1.60 LL75 1.70 L100 .6 450 -1460 L150 1.70 LL100 1.76 1.3 660 -2200 1.80 LL150 2.16 L200 2.3 930 -2850 1.90 LL200 2.28 L250 4.5 1300 -4000 L300 2.00 LL250 2.50 6.5 1550.4800 2.10 LL300 2.66 L400 11. 2050-6300 L500 2.25 LL400 3.10 20. 3000 -8500 2.40 LL500 3.35 L600 40. 4000 -12000 L750 2.65 LL600 3.00 65. 5000 -15000 2.80 LL750 3.20 L1000 100. 6200-19000 3.00 LL1000 3.75 L1250 125. 7000 -21000 L1500 3.35 LL1250 4.16 175. 8200 -25000 3.60 LL1500 4.68 POSTPAID TO ANY PART OF THE U. S. OR CANADA. DE FOREST COIL MOUNTINGS Cat. No. LC- I00- Inductance coil mounting without base, but with gears to hold three coile.s8.00 Cat. No. LC -10I -Same as above, but mounted on oak base, complete Cat. No. ULC -100 12.00 -Same as LC -100, but mounted on unit panel 10.00 Postpaid to any part of the U. S. or Canada. GREBE STANDARD DIALS WITH KNOB COMPLETE Suitable for variometers, couplers, condensers, etc. No. Cat. PDA 0'- 100' -4 inches die. Bakelite $3.00 Cat. No. PDB 0'. 50 °-4 inches dia. Bakelite Cat. No. PDD 2.50 0'. 50' -3 inches dia. Bakelite 2.25 Postpaid to any part of the U. S. or Canada. Note: -These dials are used on all Grebe apparatus. EXCLUSIVE DISTRIBUTORS OF GREBE PRODUCTS IN NEW ENGLAND Some good territory open to live dealers. Write for proposition) REMEMBER: -All this material is carried right in stock and shipped the same day as order is received. GIVE US A TRIAL. Send 6 cents in stamps for NEW CATALOG JUST OUTI EVERY AMATEUR should have it. F. D. PITTS CO., Inc. DEPT. C BOSTON, MASS.

You benefit by mentioning the "Radio Amateur Neros' when writing to advertised.

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS iN5

A Sensitive Amplifier By RAY T. FOSTER IMIGNON "RW4" (Continued from page 350) UNDAMPED WAVE Now place a battery and your phones to the other two binding posts and you are RECEPTORS ready to tune in, although before you tune in it is best to use your buzzer and adjust the carbon in the cup to such a level that it will give the loudest signals. It will be Loose Couplers seen that when current comes from the detector circuit the magnets will act on the Loading Coils iron strip which in turn causes the brass pin to vary the contact with the carbon in Variameters the cup. If a bridge circuit such as de- Amplifiers scribed by Mr. Benson in a previous issue NO is used it will perhaps increase the efficiency to some extent, or a small telephone "RW4," Size 12" z 9" z 6;¢" Strongest, Most Distinct Signals induction coil could be placed in the circuit with the phones and the battery. A circuit is shown in Fig. 3 wherein the amplifier is used in connection with an IMPORTANT NOTICE audion detector. Ernest C. Mignon, inventor of the famous disc -core undamped wave

. . .. ,. . receptor, is no longer connected with the Mignon Wireless Corporation, of Elmira, N. Y., or their successors -the Universal Radio Mfg. Corp. Amateur Antenna Design Address all communications for Mignon apparatus to By E. T. JONES MIGNON MANUFACTURING CORPORATION, Newark, N. J. (Continued from page 358)

height of sixty feet, is shown in Fig. 3. DAMPED AND UNDAMPED WAVE Here it is seen that an antenna of the fore- APPARATUS FOR ALL PURPOSES going type only forty feet in length has a natural period of one hundred and ninety meters. Endorsed by Radio Department of D., L. & W. R. R. Co. Figs. 4 and S will prove of value to those of desirous of finding the natural period Write for Literature. their receiving antennae if constructed along the lines pointed out in the beginning MIGNON MFG. CORP. r Antenna /00 feel In height NEWARK, N. J.

600

700 \ o...... e a.....o..... r....r. r el a. 600 . sal 4)\ ® n111 -n \\x. '

O INTERNATIONAL

b 50 00 0 n0 tD a0 de e0 /50 M7 Ife DO 'e At length of span in fee/ VACUUM TUBE DETECTOR AND fig 5 s AMPLIFIER, AND TWO STAGE Wavelength and Span Curve for Antenna 100 AUDIO FREQUENCY AMPLIFIER Feet In Height. fourteen spaced This detector and amplifier unit is one of a series of interchangeable panel i. e., four wires number Company is two feet apart. units for receiving which the International Radio Telegraph as new line and laboratory appa- uses these graphs in de- manufacturing part of its of experimental If the Amateur about 350 signing his transmitting antenna he will be ratus. The two -stage amplifier will multiply signal strength the x panels and are all one step towards better co- times. The units are all same size, having 6" 63" taking more combined and in- operation in the widespread endeavor to cut fitted to standard well -finished cases, so that they may be These instruments include detectors, con- down interference from amateur installa- terconnected in any way desired. as in various bulletins. tions. densers, inductances, amplifiers, etc., described our Write to Department 22 for our new circulars. JAPAN HAS NEW STATION. The Detector -Amplifier is priced at $35.00 each, without tubes and the Two - Stage Amplifier at $42.50 without tubes. F.O.B. New York City, cash with The new high -power Japanese wireless arse,. station at Tokio, which will communicate directly with a radio station on the Pacific INTERNATIONAL RADIO TELEGRAPH COMPANY coast of the United States, will be com- New York City o° pleted soon. Trial exchange of messages 326 Broadway will be made at once with the American \\wi.wa\ au\ uuuu uuuuuuuuuuu Pacific stations, and if satisfactory results tft are obtained the radio station will be opened to the public for acceptance of messages. LEARN WIRELESS TELEGRAPHY WANTS RADIO STUDENTS. Fascinating and Educational Work -Big Salaries- Propane Now the local army The United States Shipping Huard is making heavy demands upon us for Dodge- tralned wirelessoirr. Efforts are being made by tree, unsurpassed living accommodations and earn a bigsalary. of men atone. Travel all over vac world, secure, recruiting office to recruit a number We Also Teach Morse (Wire) Telegraphy and Railway Accounting for the army school located at Little Silver, School eetabllshd 45 years. Endorsed by wireless, railway and telegraph officials Low N. J. The school is for the training of rates. Students can earn living expenses while nt'ending school. Catalog Free. Writs Today. men in the radio and wireless telegraphy Dodges Tel h and Wireless Institute 26th St.. Valparaiso, Indiana divisions of the army. You benefit by mentioning the "Radio, Amateur News' when writing to advertisers.

www.americanradiohistory.com 386 RADIO AMATEUR NEWS

The Priess Loop Set 4 Famous Books! (C ontintted front page 334) ...... ,.,

packing 1 swells , when oil reachesw it, thus effecting a tight joint. The stuffing box is adjustable. The condenser will withstand 4,400 volts effective.- (Photo- graphs by courtesy of Wireless Specialty Apparatus Co.)

EACH ONE A BIG SUCCESS!

THE BOOKS YOU Here Is Shown the Mica Transmitting Con- MUST denser of the Priess Set. Note the Switch Arrangement. HAVE

Wireless Course in 20 Experimental Electricity No. 1. How to Make Wireless Apparatus Lessons Sending Course in 20 Lessons No. 2. How to Make Wireless By S. Gernsback, A. Lescarboura and By S.Oernsbaok and H.W.Secor.E.E. H. W. Receiving Apparatus Seoor. E. E. By 20 Radio Experts A Course of the theory and prac- A course that tens you everything you tice of Electricity for the Experi- Two Remarkable Books Want to know about 'Wireless' start- menters. One of the most complete Both Paper Bound ing off In lesson No. 1 by explaining and comprehenelve treatises of this Book No. 1 contains 100 pages. size the Principle. of Electricity. By special subject ever published. Writ- 7 x 0 m. and 88 illustrations. simple, easy stages. this wonderful ten Course by the same authors as the Book No. c contains 100 pages, sise takes you into "Wireless" famous Wireless 7 by the Course." x 5 in. and 90 illustrations. use of such simple language so Every phase of experimental elec- Written ano published entirely for skillfully used that of necessity you tricity is treated comprehensively the wireless entuusiast who wants must understand every word. There in plain English. New Experiments to make his om. radio apparats. s a whole lesson devoted to the are described Theory and and explained and Oeil) strictly modern radio apparata kfathemahcs of this epoch nearly every application of Elec- are described and the Illustration. marking eublect. The Ian lesson Is tricity in modern and descriptions devoted tc a life is given in are so clear and history of Wireless. simple language. simple that no trouble will be expe- Size of book Is rienced In making the Instruments. 7 x 101/4 In., 160 Th. book contains 128 pages and oases. 350 illustrations, 90 tables. more than 400 Illustrations. Book No. I -How so make Wireless clothth cover.... Sending Apparatus 25o per copy 75e Flexible cloth cover-per copy 750 Book No. 2 ta make Stiffexible cover copy51.25 -How Wireless per Stiff cloth serer per copy$1.25 Receiving Apparatus 25e Postpid Postpaid Postpaid The Loop Transmitter Set Up Ready for Use. THE EXPERIMENTER PUBLISHING CO., Book Dept., 233 Fulton St., New York Article No. 3 in our February issue coil describe the receiving section in detail with detail photographs. The Guaranteed "Better Quality" B-Batteries The Only Genuine and Original B- Batteries that the Signal Corps, U. S. Army and Navy Use LOW PRICES AS COMPARED TO OTHERS We have decided i make our prices as low as possible regardless of expensive made. Many wonder the materials from which our "BETTElt QUALITY" B- Batterlea are why we can make the price so low, but It Is because we live up to our motto "RETAILING AT WHOLESALE PRICES" Amount CAT. No. Voltage of Cells Type Kind Dimensions Average Life List Value Our Price BB -154 22;¢ 15 BA -2 Signal Corps, U. S. Army 334 "x2 "x23¢" 4 months $1.50 $1.25 Postpaid add 10c. In Canada and foreign countries add 35c. BB -158 22!¢ 15 BA -2 Signal Corps, U. S. Navy 63¢ "x4"x3" 8 months 2.50 2.20 Postpaid add 35c. la Canada and foreign countries add 50c. SBB -3012 45 30 BA -2 Spl. comb. Navy and Army 14 x8 "x6" 1 year 6.00 4.35 Postpaid add 70c. In Canada and foreign countries add $1.00 We Guarantee each and every "Better Quality" B- Battery on a moneback basis. No higher claims can he made more honestly. We can Drove It. ORDER THROUGH YOUR DEALER. THIS WILL SAVE TIME AND MONEY Or if your dealer does not handle our "BETTER QUALITY" B- Battery. send us your order and dealer's some and address. Your order will be filled within four !sours. DEALERS: WRITE FOR PROPOSITION. TERRITORY NOW BEING ALLOTTED. THE H. S. WIRELESS CO. 164 Ross Street, Brooklyn, N. Y. WRITE FOR DESCRIPTIVE BULLETIN REGARDING WHY OUR "BETTER QUALITY" B- BATTERIES ARE BETTER QUALITY. IT'S FREE.

You benefit by mentioning the "Radio Amateur Newt' when writing to odvertisrrr

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 387

... ,.,,,..,,,,,,,,,,,,, A Case Of Nerves By J. K. HENNEY (Continued from page 360)

treme terror into which I soon found my- self." Miggsby shuddered as tho the recollec- tion of the affair were proving too much for him. Boyd huddled closer to the huge mate and seemed to be trying to avoid the eyes which so earnestly sought his own. The unusual paleness of their faces con- Our New Catalog "H" trasted strangely with the glow of the / small lamp over the operating desk. The Contains 24 pages of instruments, raw materials and seething waters outside seemed never to A complete line of high recede, the wl istling of the wind thru the parts you can't afford to miss. rigging seemed to be increasing in violence. grade, moderate priced apparatus including switch At the end of a few minutes of silence, switches, meters, plain and threaded brass the whistle announced the r end of the points, knobs, watch, its earsplitting roar only aiding the rod, copper strip, binding posts, screws, nuts, washers, etc. feeling of dread that seemed to be filling the boy's heart. He wanted to get away, 5c in stamps for your copy today and get on mailing to get into his bunk and to pull the covers Send tightly about his ears, but the large eyes list for future Bulletins. of the mate seemingly commanded him to remain. I don't know how long I sat there," said SHOTTON RADIO MANUFACTURING COMPANY Miggsby, "never daring to take my eyes from the book. The obvious thing of P. O. BOX 3, SCRANTON, PA. course. was to get my revolver, walk to N. Y. the door, and. to face my nocturnal visitor. BRANCH: 8 Kingsbury St., Jamestown, Yet as the minutes fled I realized more and more that it would take an almost super- human effort to do anything except sit there, never moving, hardly thinking in my stupor of fear, until the unknown person came in and finished me off. I realized soon, however, that something must be Vacuum Tube Socket done to put an end to the strain and re- The "ACE" lieve my mind of its foolish fancies. Sud- The Ace Vacuum Tube Socket is de- denly I thought I heard a rustle at the four prong door, and in my disordered mind's eye I signed to fit the Standard thought I heard the door knob slowly turn- vacuum tube. The top part consists ing. My terror became acute. Then a of a finished aluminum casting, horrible scream came to my ears. I jumped mounted on a formica base 1/4 inch to my feet in abject fear. I looked square break under at the door and saw nothing.. Far on the $` thick. This base will not other side of the cabin the flickering light any condition of service, as moulded of the fire cast an everchanging series of composition bases will. Heavy phos- weird and fantastic shapes on the wall. phor bronze springs are mounted on My eyes could see nothing there. Then I base for con- glanced across the room and under a table the under side of the littered with magazines and message forms, nection to the tube prongs. I thought I saw something moving in the This is the only vacuum tube socket on dense shadows. Then came that shrill cry $1.50 each the market which has the grid leak built again, this time from the operating table. used I realized that somehow my strange visitor in as part of the socket. It may be had entered the room, and was in some complete for back or front of panel mounting. terrible anguish huddled up under the The best socket on the market, regard- way entirely and with grid leak table. My nerves gave less of price. I rushed away from the place with the of speed and aimlessness of a demented per- We manufacture a complete line son. I must get as far as possible from Radio apparatus. into the awful thing at the station. Out CO., Inc. the night and gale I rushed, I knew not THE PRECISION EQUIPMENT where." Manufacturing Engineers, Dept. A Miggsby was silent. Boyd and the mate 2437 Gilbert Ave., Cincinnati, Ohio sat on the edge of their chairs, their eyes gazing fixedly at the darkness under the operating table. Neither spoke for some time. Perhaps they were afraid to disturb the spell that Miggsby had cast upon them. Perhaps they imagined that the unseen WIRELESS AMATEURS presence of the radio station would invade Send 2 -cent stamp for free description of the Rollybelle if they broke the silence. Finally the mate's curiosity conquered. The Barr Mercury -Cup Detector "Well ?" he queried. by "Well," said Miggsby with an odd smile - The most efficient detector on the market. Tested and a shrug of his shoulders, "I guess The Marconi Wireless Telegraph Co. and the United that's all. It was only a case of nerves. States Government. The cries I had heard were the death sig- Increases the efficiency of every wireless receiving nals of the freighter Pleiades. She sank the signals clear, sharp and distinct. fired lai set by making a moment later with all hands. I was Mal Instantly adjustable at a constant pressure. I am _ - for leaving my post. That's why Dept. B, THE WYOMING, here." The BARR Mercury -Cup Detector WASHINGTON, D. c. JAZZ WIRELESS MUSIC BY RADIO AND TELEGRAPH SCHOOL Amateur wireless operators in many MASSACHUSETTS and Evening Classes by jazz music RADIO AND TELEGRAPHY Day cities are being entertained Tel. 7165 Boston. and grand opera sent out from the United IS Boylston Street States navy station at Chicago, Ill. when nritiap to edvartisws. You benefit by menttonisg the "Radio Amateur News"

www.americanradiohistory.com 388 RADIO AMATEUR NEWS

,,.M,,,,,,,,,,,,,,,,,, ,,,,,,,,.,,,,,M,,,,,,,,,,.,,,,.,,,.,,,,,,,..,,.,,.,,,,,,,,,,,,,.,,,,,,,.,. g -264 Pago. Nical 13 I Want To Know eleBiss and Electre (Continued from page 3701 DUCK'S NWeirw Th ,nalwtkkce. Catalog It will be mailed for 12c in stamps or coin which may be de- WAVELENGTH OF LOADING ducted on first order of $1.00. Catalog not sent otherwise. COIL. 1,v e regard this catalog as our greatest effort. It embraces every- (116) Walter C. Dux, Memphis, Texa., asks: thing in wireless worth while. 172 pages with no waste space devoted exclusively to wireless instruments. Your amateur Q. 1. Please give me the wavelength of a loading friend will tell you that there never has been any wireless coil 30 inches long and 4 inches catalog in diameter wound to take the place of catalog of this company and above all that you can absolutely with No. 28 S.C.C. depend magnetic wire. on our goods. There is no need for any other catalog when you have this big catalog. A. 1. Approximately 10,000 meters. Q. 2. Also could I receive undampt with A big improvement over our the same former model. Primary divided loading coil, 5,000 meter loose into four sections, with three coupler, two .001 mfd V.C.'s, an audiotron dead end switches, greatly im- bulb, fixed condenser and proving selectivity. a pair of 2,000 ohm phones with a four -wire aerial No. 4 Secondary divided into three gauge, 110 feet sections, with two dead end long and 40 feet high. switches, eliminating harmon- A. 2. Yes. ics. The change in the con- Q. 3. Also what is the wavelength of struction of the guide rod sup- my aerial. port makes it possible to obtain a looser coupling. It is a won- A. 3. 400 meters approximately. derful improvement over our old model both in performance and appearance. Only $23.50. MEANING OF MEGOHM. (117) Henry Chung, Honolulu, Cahu, NEW MODEL 5BB. NAVY TYPE RECEIVING TRANSFORMER asks: Q. 1. What is the wavelength of my aerial, which is 60 feet long and thirty feet high, and The secondary on our new consists of four strands of No. type Arlington is divided into 12 bare copper wires? .hree sections with two dead A. 1. Approximately 250 meters. end switches eliminating dead Q. 2. end effect and harmonics and Will you hook up the following giving greater selectivity. The apparatus: 3,000 meter loose coupler, 2 end support is similar to that on our Navy type permitting a looser coupling. It is a beau. tifully finished instrument. Price only $10.50. OUR IMPROVED ARLINGTON RECEIVING TRANSFORMER

THE WILLIAM B. DUCK CO., 230 -232 Superior St., Toledo, Ohio

HIGH GRADE VARIABLE CONDENSERS DESIGNED especially for back of panel mounting. If you are building a new receiving set or are making some changes in the one you now Circuit Using a TwoPoint Switch to Change have, you will need several good variable con. from Spark to Arc. deniers. These are the best you can get, and are offered at prices within the reach of practically every experimenter. 43 plate condensers, 1 fixed condenser, pair 2,000 We are making a specialty of manufacturing of ohms receivers, 4 volt storage bat- these condensers, and the best of materials Is tery, Marconi vacuum tube detector rheo- used throughout. The plates are of heavy gauge stat? aluminum, die stamped, which are heavy enough to stay flat. The spacers are very accurately ma- A. 2. Hook -up given herewith. chined from brass. One excellent feature Is the Q. 3. Can you explain the word meg- Bakelite- Dilecto end supporting plates and bear- ohms to me? ings, which Insures perfect insulation and low A. 3. capacity when at zero. Fitted with drill rod shafts, The prefix mega means 1,000,000. accurately ground to size. A copper ribbon sold- Therefore a megohm is 1,000,000 ohms. ered to the movable element insures perfect contact. Fitted with polished, lathe turned knob and pointer and mounting screws, In brass or LOOP AERIAL. nickte finish. In ordering, specify thickness of (118) Stewart W. Smith, Warren, panel and whether brass or fickle metal parts are Ohio, wants to know: desired. Q. 1. Can a loop aerial be used to receive messages from a station which is us- PRICES ing both aerial and ground, without hav- 2 plate Vernier $1.85 ing a ground connected to the instruments? 7 plate .0001 m.f. max. capacity $2.15 1. 13 plate .0002 mi. max. capacity $2.50 A. Yes, a loop aerial may be used to 17 plate .0003 m.f. max. capacity $2.85 receive messages from any radio station. 23 plate .0005 m.f. max. capacity $3.25 No ground connection is necessary when 31 plate .0007 m.f. max. capacity $3.90 receiving with the loop. 43 plate .0010 m.f. max. capacity $4.75 63 plate .0015 m.f. max. capacity $6.75 Q. 2. Can a loop aerial be used for Include postage for one pound transmitting purposes? A. 2. See question 114 elsewhere on THE WIRELESS SHOP A. J. Edecomb these pages. 511 West Washington St., Los Angeles, Cal. GRID CONDENSER. (119) Clifford G. Fick, Sioux Falls, S. MEMORIZE CONTINENTAL CODE D., asks: UNIVERSAL SYSTEM Q. 1. Whether there would be any ad- ALMOST INSTANTLY RADIO APPARATUS vantage in using a De Forest Variable Con- Sly method Is the short cut. Complete chart denser of .0005 mfd. capacity for a grid and full Instructions, 10 cents. Efficient Equipment for all purposes condenser on a Marconi "Vt," over an ordi- Damped and Continuous Waves nary fixed grid condenser? C. K. DODGE Send stamp for catalogue A. 1. There is an advantage in using a Mamaroneck, N. Y. UNIVERSAL RADIO MANUFACTURING CORP., variable grid condenser although some Dept. W.. Elmira. N. Y. authorities do not agree in this matter. You benefit by 'mentioning the "Radio Amateur News" when writin g to advertisers.

www.americanradiohistory.com January, 1920 RADIO AMATEUR NEWS 389 MAGAZI Príce Slashe

of magazine subscriptions expire this month! With tremendous advance of paper prices and labor It is certain that nearly all magazines will advance their Millions subscription prices at least from 25% to 50%. The BY ORDERING NOW YOU WILL SAVE BIG MONEY. In announcing these wonderful prices it is with the absotute Publishers knowledge that our readers are offered the lowest prices for standard Magazines that it is possible to obtain anywhere. Will Mail the Only by special arrangement with the publishers are these prices possible, but to take advantage of them, Magazine you must act quickly. Don't delay, do it now. This offer is so good that of necessity it must be limited in time. Direct From Just think of buying standard Magazines at reduced prices in time for Xmas Presents, and they certainly make ideal Their Own gifts being a constant reminder for a whole year of a con- siderate friend. Just glance over our wonderful prices, and see Office to You. how we enable one dollar to bring you two dollars' worth, and then make up your list. When sending your order, don't forget to state where magulnes are to be sent. But be *tire you do it now. To- morrow means you may forget and lose this wonderful opportunity. all prices quoted are for subsCHbers In U. S. A. only, Canadian and Foreign subscriptions require additional postage.

BIG SPECIAL TO Radio Amateur News...21.50 Radio Amateur News...81.50 Our Price Radio Amateur News...31.50 Our Price "WIRELESS BUGS" Scientific American 5.00 OurPrice Boy's Magasine 1.50 St. Nicholas 3.00 Big Everyday Engineering 1.50 Radio Amateur News ..$1.50 Regular Price $3.00 2.50 Regular Price $4.50 3.75 Electrical Experimenter. 2.00 Special Regular Price 18.00 7.00 News...11.50 Vlreleas Ape 2 00 Radio Amateur to You Everybody a 2.00 Our Price Radio Amateur News...81.50 Q. S. T I So 2.00 Our Price Everyday Engineering... .50 Radio Amateur News...11.50 Our Price Delineator Boya Magazine 1.50 Wireless ßbí s life 2.00 World (London) 2.75 Price 4.25 2.50 $10. 3.10 Regular 15.50 Regular Price $3.00 111.24 Regular Price 13.50 Radio Amateur News. $1.50 American Magasine 2.00 Our Price Radio Amateur Newe...81.50 Our Price Radio Amateur News...$1.50 Our Price Women's Home Com- Today's Housewife 1.00 Radio Amateur News...81.50 Popular Science 3.00 Electrical Our Price panion 2.00 Experimenter. 2.00 4.25 Regular Price $2.50 2.00 Regular Priee..... 14..50 4.00 Regular Price Regular Price 35.50 $9.50 3.00 Radio Amateur News...81.50 Radio Amateur News...11.50 Wireless Age 2.00 Ow-Price Popular Science...... 3.00 Our Pnte Radio Amateur News...11.50 Illustrated World 2.00 Electrical Experimenter. Winder Age 2.00 Our Price 4.75 5.75 Electrical Experimenter 2.00 Regular Price $5.50 Regular Prie ...... $6.50

Regular Price $5.50 4.75 Special price Special price With Radio Amateur News...11.50 Our Price Retail (Radio Retal (Radio Wireless World (London) 2.75 Club Price Amateur Club Price Amateur Ne. Magazine Singlle News) No. Magazine Single News) Regular Price 84.25 4.00 60 Adventure 39.00 54.25 60 Metropolitan $3.00 $4.25 40 American 2.00 3.25 27 Modem Priscilla 1.50 2.50 93 Boy's Life 2.00 3.00 25 Boy's Magazine 1.50 2.50 Motor 3.00 4.25 70 Century 4.00 4.75 Motor Boating 2.00 3.25 45 Christian Herald 9.00 9.50 5tuusey'a Magazine 9 00 4.25 Conquest (London) 5.75 4.50 20 McCall's Magazine 1.00 2.25 Cosmopolitan 2.00 3.25 45 McClure's Magazine 2.30 3.50 Country Gentleman 1.00 2.25 70 Outing 4.00 4.73 100 Country Life 5.00 6.25 20 Pathfinder 1.00 2.25 60 Current Opinion 9.00 4.25 40 Pictorial Review 2.00 3.25 40 Delineator 2.00 3.25 60 Popular Science 3.00 4.25 50 Dniester 1.50 2.75 50 St. Nicholas 3.00 3.75 40 Everybody's 2.00 3.25 Saturday Evening Post.. 2.00 3.25 84 Etude (For Bugle Leven) 2.00 5.00 95 Scientific American 5.00 5.75 $5 Field & Stream 2.00 3.00 75 Scribner'' 4.00 5.00 Bed Housekeeping 2.00 9.25 System 9.00 4.25 Harrier's Bazar 4.00 5.25 13 Today's Housewife 1.00 2.00 Hearst's Mamalee 2.00 3.25 35 Wireless Age 200 3.00 35 Illustrated Wend 2.00 3.00 40 Woman's Home Companion 2.00 9.25 Ladles' Homo Journal 1.75 3.00 60 World's Work.... 4.00 4.25 Literary Digest 4.00 5.25 50 Youth's Companion 2.50 3.75 For computing together Magazines listed separately. add Class Numbers before title end multiply by 5, giving our pride to you In dollars and cent. Write for Special Prices on ANY Publication not listed here We will save you money SEND ALL ORDERS TO "CIRCULATION DEPARTMENT" EXPERIMENTER PUBLISHING CO., Inc. 233 Fulton Street, New York City, N. Y.

to advertisers. You benefit by mentioning the "Radio Amateur News' when writing

www.americanradiohistory.com 390 RADIO AMATEUR NEWS January, 1920 IP '0&,uaui:uv"N/N.6UWlIV:p"t/"\/4\W!t.b'LN/bU10.0!L&J0104LVJLN/Jl>`/Jrti'J/szÁIA/'wJM:LN/JCN.l'NiJU/: Iu:u Naupww: uv:'.v:uNpwr./!fv.uuwut: OPPORTUNITY AD -LETS Follow these advertisements every month. Reliable advertisers from all over the country offer these columns. you their most attractive specials in Classified advertising rate two cents a word for each insertion. Ten per cent discount for 6 issues, 20 per cent discount for 12 issues. No advertisement for less than 20c accepted. Name and address must be included at the above rate. fied advertisements unless placed by an accredited advertising agency. Cash should accompany all classi- Objectionable or misleading advertisements not accepted. Advertisements for the March issue must reach us not later than February II. THE CIRCULATION OF THE RADIO AMATEUR NEWS IS OVER 30,000 EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street. New York, N. Y. iaerisv-ritiñehrr-iiilri.arravlrriii!ri!rr'reñrawasIrirormre tr. ireIrieaieriehravvrenriehraF!riehriaiiriaifriat! -rr.i!;rañrieriairieñri. írigirietir-sanriahrieñyañr'ieiuiaitrnmrrsahr errn - t. ñ, - - Aeronautics. For Men. Exchange. 100 Model Aeroplanes. Good flyers. ssc brings Safety Razor Blades resharpened, double For Sale edge, 35c -One pair Brandes "Navy" phones, Working Drawing and prices. F. Bruland, Red - per dozen; single edge ase per dozen; practically we pay postage. Write new, cost $i .00, sell for $io.00. C. tord, Mich. Star Safety Razor Sharp - M. Cardeza, teas Locust ening Co.. 60 Chestnut St., Northside, Pitts- St., Philadelphia, Penna. burgh. Wanted -A good long distance receiving net cabi- Business complete with aerial. Lock Box No. 17, Opportunities. Detectives Earn Big Money. Travel. Great Washburn, Illinois. demand. Experience unnecessary. We 5.30 per 100 paid for names and addresses. Par- train Audiotron, you. Write for free particulars. American De- new double filament. 54.25 post ticulars free. Victor -King Co., 36 Bromfield St., tective System, 1968 Broadway, paid. Raymond K. Kehler, Abilene, Kansas. Boston, Mass. New York. For Sale-Set Hawkins Guides, never used, Can You Draw? Chalktalking offers a splen Health. first money order, seven fifty, takes. Carl did opportunity to make money. Particulars Pyorrhea (Rigg's Disease Bleeding Kuickrehm, 5553 Elgin Ave., Forest Park, Ill. free. Truman's Chalk -Talk Studio. Box 765 - or Swollen Gums). H. E. Kelty, D.D.S., M.D. Sell-One -sixth KW. transformer, never used; Perrysville, Ohio. pyorrhea specialist for 15 years, has developed key; other apparatus. Write, Larson, sae West $30.00 a Week Evenings. I made it with a a successful home treatment for pyorrhea St., Worcester, Mass. small mail order business; continued my reg. Purifying, healing, preventative. Full month's For Sale -Audion Detector, Amplifier, Navy ular job daytime. Free Booklet tells how. ac treatment, $t postpaid. Or, write for free loose coupler, two loading coils, 54 KW. Thor - postage. Albert W. Scott. Cohoes, N. Y. booklet. Pyorem Mfg. Co., 439 Seventh St., darson transformer, Brooklyn, N. Y. Condenser, Oscillation Oklahoma ranch farm and oil lands; Soo acres transformer. Sell cheap. Write. Alonzo Ma. Lenore county, Oklahoma; fine farm and ranch Tobacco or Snuff Habit Cured or no pay; si ginnis, Rochelle, Illinois. and near gas well that had ato feet sand; if cured. Remedy sent on trial. Superba Co., Wireless Apparatus $7.50 SB, Baltimore, Md. for Sale or exchange for a acre. R. E. Lynch, Tulsa, Okla. good lathe or a tool box. Let me know what you want and what you have; have Detector Collect and Sell Names and addresses in your IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIOIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIW111101011111111111001111111111111 (- stands. Old style DeForest Lamps, Audio Tron Two spare time. No canvassing. Details. soc in filament lamps, coin. L. Stultz, Middletown, Maryland. CARL A. HANSEN and other apparatus. Address O. M. Radio, Post Office Box 549, Jersey City, Stamp Names on Key Checks; spare time 828 EIGHTH AVENUE N. J. make as high as $19 a hundred. Send 25c BROOKINGS, For Sale -Complete receiving, sending wireless for sample and instructions. Returned if re. SO. DAK. set. Send for list of instruments -too numer- quired. Elct Keytag Co., Cohoes, N. Y. ous for advertisement. $75.00. Charles Riedle, Experimenter Pub. Company, Inc., 7357 So. Peoria St., Chicago, Ill. Books. 233 Fulton Street, For Sale-Loose Coupler, 3,000 meters, $5.00. MultiAudiFood, $54.00. Panel Detector Set Books -Practical Mechanical. Auto, Aviation, New York, N. Y. with Audio Tron Bulb, $10.00. Herman Siegert, Home Study Books; easy payments. Semi dime Grayville, Ill. "tonight" for catalogs. Amsco. Dept. Gi. Aurora, Gentlemen:-Enclosed is $3.74, for For Sale -Pathescope moving picture machine Illinois. which insert the enclosed ad in the in good condition. Write Science Club, Belle- vue High School, Bellevue, Pa. Nature Laws every married and engaged February, 1920, issue of the Elec. Sell- Galena detector person should know 5oc. Central Company, nos trical Experimenter, and Radio three magnetos wall tele- Ninth Ave., New York. phones, loading coils, condenser. moo Ohm Amateur News. Phones. Write, enclose stamp, Edward Weitz, Mechanics. Learn how to . read blueprints. Both of your magazines are 6704 Deary St., Pittsburgh, Pa. Complete I69-page cloth bound book with sas GREAT and I couldn't get along Buy, Sell, Exchange. Wireless and elec illustrations mailed for Sz.00. You cannot lose; trical goods. Murdock, Clapp -Eastham, your money refunded if not satisfied. Educa- without them. As to the R.A.N. Thor. darson, Brandes, etc. Send toe stamps for our tional Institute, '139 Rewland Bldg., Detroit, it's the best in its line. I am watch- circular listing new standard Michigan. apparatus at less ing for the day when the Wireless than manufacturers prices. We have to exchange; Wireless, Experimental Electricity Course in so lessons. Electrical, Optical, Cameras, Telephone will be in common use, Printing Presses, Typewriters; By S. Gernsback . and H. W. Secor, E. E. A and to large list free. course of the theory and practice of Electricity help along the cause, I am LaRoy Zahrbach, z5 College Ave., Hiram, Ohio. for the Experimenter. Every phase of experi- subscribing to the R.A.N., for I For Sale-Audion control cabinet 8xioys inches. mental electricity is treated comprehensively in know that it champions all those Crystal and Audion detector with two-step plain English. New Experiments are described NEWEST IDEAS in the Wireless amplifier. Oscillating Audion with two -step and explained and nearly every application of amplifier without tubes $65. Also cabinet same Electricity in modern life is given; 16o pages, 400 line. s:;re, Cry stal and one -step amplifier. Oscillating illustrations. Flexible cloth cover, 75c postpaid; Yours for PROGRESS! ion and Audion detector without tube, $eo h seta stiff cloth cover, 51.25 postpaid. Experimenter CARL A. HANSEN. oscillate from too meters up. Also Publishing Co., Book Dept., 233 Fulton St., New short wave regenerative receiver cabinet dame York City. size contains two 43-plate condensers, tickler, 711111111111111111fl111111IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIl01101111I1 =111IIIIII 1111IIIlIIl011111111111111111M12 etc., $2. Siebert, 267 Radde St., Long Island Wireless Course in 20 L By S. terns. City, N. Y. back, A. Help Wanted. Lescarboura and H. W. Secor, E. E. For Sale- 15,000 meter Navy coupler, Su; Tells you everything you want to know about Earn $25 Weekly, spare time, writing for news- tS,coo papers, magazines. Experience loading coil, $4; rotary disc, $z; Emerson induc- "Wireless"-theory, practice and history. A unnecessary; de- tion motor, needs rewinding, tails free. Press Syndicate, 5665, St. Louis, Mo. $3; four pounds clear, concise course on every phase of this 12 D.C.C. wire, $a. Might consider Marconi subject; 16o pages, 35o V. T. illustrations, 30 tables. Detectives make big money. Travel, be your Ralph Haynes, 655 Woodlawn Ave., Canon City. Flexible cloth cover, 75c postpaid; stiff cloth own boss. Either sex. We instruct, small cost. Colo. cover 15.2 postpaid. Experimenter Publishing Write Johnson's Detective School, 232 Sheldon Will Trader s Burrough's Co., Book Dept., 233 Fulton St., New York. Ave., Grand Rapids Mich., Parlor Billiard or Dept. A. Pool table, pair Boxing gloves crokinol Board BE a Back Numbers R. A. N.-Have you missed a Mirror Expert. $3$io a day; spare time flashlight for pair Brandes 1 'Variables, Helix copy of the Radio Amateur News? Now is our home at first; no capital; we train, start you Step down Transformer, Lighting Switch. All chance to get it. We can making and silvering mirrors French method. goods guaranteed. Paul Craugh, Liberty furnish copies ofy Free sir St., August, September, October November and prospectus. W. R. Derr, Pres., 579 Decatur Penn Yan, N. Y. De. St., Brooklyn, N. Y. cember issues at isc each. Orders filled immedi- Se-foot Aerial, Insulators, Detector, Loading ately. Experimenter Publishing Co., Book Dept., U. S. Government wants hundreds Railway Coil, moo ohm Receiver, $6.00 Cash. William 233 Fulton St., New York City. Mail Clerks immediately. Men, women, 58 to 35. Stasaitis, 356 Bainbridge St., Brooklyn, N. Y. $y3oo first year. Raise to $a,000. Just off the Press. Design and Construction Vacations of Audion Amplifying with full pay. Women appointed to office work. Patent Attorneys. Transformers (Radio and Permanent life positions. Common education Audio Frequency Types) By Edward T. Jones, sufficient. Patent Attorney. Consulting Engineer. High late Associate Editor Radio Amateur Pull unnecessary. Examinations com- class patent service in all its branches. Write News. A ing everywhere. List government openings free. book that every radio "bug" should have. Writ. for particulars. M. H. Loughridge, 1457 Broad- ten so you Write to-day, Franklin Institute, Dept. 0.584, way, New York. will understand every word. Price Rochester, N. Y. 25c postpaid. Experimenter Publishing Co., Book Become Million. spent annually for ideas" Hundreds Dep't., 231 -A Fulton Street, New York City. Auto Experts. Hundreds needed. 835 now wanted! Patent yours and profit! Write to- week. Earn while learning. Franklin Institute, day for free books how Dept. 0.856, Rochester, -tell to protect yourself, N. Y. how to invent ideas wanted, how we help you Chemicals. Secret Service Operatives and Detectives are sell., etc. ,.3oz Patent Dept., American Industries, in demand. Earn big money. Travel every- Inc., Washington, -D. C. Experimental Chemists: If you want prompt where. Fascinating work. Learn this profession service and quality chemicals and apparatus. by home study. Particulars free. American For Inventors. give us a trial order. Sample Prices. Ring School of Criminology, Dept. R, Detroit, Mich. Inventors -We do experimental, stand, so cents. Small rings, ao cents. Large Model, Teel, rings, as cents. Four ounce glass Die and Jig Work; Light Manufacturing. Miller mortar and News Correspondence. & O'Brien Mfg. St. pestle, 4o cents. 6" test tubes, 25 Co., Paul, Minn. cents dozen. Earn $25 Weekly, tubes, 14 spare time, writing for Inventors-Models, Dies Tools; Thistle cents. 8 ounce flask, J5 cents. newspapers, magazines. as years' ex- You need our catalogue. Mathewson, Morell Experience unneces- perience; work guaranteed; lowest price. Manu. sary; details free. Press Syndicate, 566 St. facturing St.. No. Weymouth, Maas. Louis, Mo. of specialties our hobby. Peerless Die & Tool Co. izi Opera Place, D. B., Cincinnati, O. You benefit by mentioning tir "Radio Amateur News' when writing is attentions.

www.americanradiohistory.com January. 1920 RADIO AMATEUR NEWS 39 I

Office Devices. Auctioneers. Multígraphs, adoressographs folders, duplica- Auctioneers -Makes big money. Free cata- tors, sealers, bought and sold. Office Device logue. Carpenter's Auction School, Kansas City. Company, saa -W North Wabash, Chicago. For Advertisers. Printing. Money? Jacobus Art Ads make small space 3,005 Two -Color Labels, 51.35. Irvin J. Wolf, dividends. Price $5.1.0. Write to -day. PIN pay big Station E. Philadelphia. cobus Service, to73 Sanford Ave., Irvington, Fifty classy name cards printed in gold. 5oc, Durso, Dept. so, as Mulberry, New York City. Wireless. iso Note Heads and am En- US Letters Heads, The Audion. Its early history and develop- One Dollar Print, velopes, postpaid, 8a.00. Commercial and Trigger Action. Delaware. ment, Electron Theory Wyoming, Compiled by a Chief Electrician Radio, who was Post Cards. stationed at the Naval Radio School as instruc- two written by an old amateur Membership in post card exchange one month, tor for years, TO COUPON a5c. Girard, for the amateurs, in words that they can under- three art cards, lists etc., Sophie hook -ups R. L stand. Also blueprint diagrams for Box a4, Pawtucket, for Receiving Damped Signals, using both air soc Durso. SA Fun Creating Cards silver. exhausted and gas bulbs. Receiving undamped D of m. a Mulberry N. l. City. signals and regenerative circuits. Two step. Write your name and ad- Personal. Amplifier using same (A) and (B) Batteries for both steps. Wireless Telephony with Power dress plainly, mail us both, Salesman Wins- Thousands of positions a The by, Bulb. Working Blue Prints on how to build and you open. We teach traveling salesmanship mail "One to One" transformer for use with Audion by return mail and guarantee offer of position or refund tuition. Amplifier. All for Two Dollars. Address T. O. For Interesting particulars, address Kansas Vo- McKenzie. tot Warburton Ave., Yonkers, N. Y. will receive your Miltonvale, Kan. cational Bureau, Multi -Audi -Font amplifies all signals with Nubber Stamps. any detector. Upkeep cost, 5c a month. Modern Elizabeth, N. J. Rubber Stamps made to order. McCaddon Com- Radio Equipment Company, pany, Zanesville, Ohio. While they last. Heavy current telephone Skinderviken transmitters complete with lug for mounting on stamps and toms. your radiophone set. $3.00 Parts for Microfonic Best one-cent approvals in America. F. P. amplifiers etc. Satisfaction guaranteed. Mod- Hand, 1117 So. both St., Philadelphia, Pa. ern Radio Equipment Company, Elizabeth, N. J. Transmitter Hays you seen The Stamp Herald? Finest Calla-Printed on best white cardboard monthly stamp paper published. Subscription t1 x 5. Ten cents, three for twenty -five. Radio ,oc a year 3 months' trial for loc. Stamp Herald Press, lob Franklin St., Framingham, Mass. Publishing Co., Dept. E., Indianapolis, Ind. Stranded Aerial Wire seven strands of Num- BUTTON Ba- SOS all different stamps, including Bosnia, ber as pure copper. High tensile strength and varia, China, Guatemala, Bulgaria, Bohemia, too per cent conductivity. Supply limited at this Poland, Turkey, etc., and Dime Stamp Album, period. No. C. O. D.'s. s cent per foot, $9.00 only one to a customer. all for a5c. Our per thousand. Lee A. Bates, 8 Meen St., Wor- sheets S. ic cester, Mass. svalNet. diffeent Poetageand Complete Receiving Sets, H and up. With War Revenues for only 75c.. Indiana Stamp Co., i,000 -ohm receiver, tested mineral; guaranteed. Dept. E, Indianapolis, Ind. Bulletin for stamp. Jenkins, 5123 Purchase St., ncclluding 1,1111S U. S. and Foreign Stamps, New Bedford, Mass. Mexican Villa Dollar, all for a5c. CC Leumite the new ultra- sensitive detector 77 Kensington Heights, Meriden, Connecticut. crystal. Marvelous for fine adjustment and ISO Foreign Stamps. 55c. too U. S. Stamps, a5c. clearness of signals. Used by the U. S. Navy. Veale. Box 1364 Detroit, Mich. Generous crystal s5c, coin. Leumas Labora- tories, 1306 Park Ave., New York City. Song -Poéms Radio Amateurs -Get the best special non- Song- Writers Manual & Guide Sent Free! shrinkable tubes for radio work from 354" dia. Contains valuable instructions and advice. to 6%" dia. by quarter inches any length to 36 Submit song-poems for examination. We will inches. Prices very cheap; send stamped and furnish music, copyright and facilitate publi- addressed envelope for price list. Sennett & Co., cation or sale. Knickerbocker Studios, 311 to Court St., Hoboken, N. J. Gaiety 'Bldg.. New York. Wireless telegraph and telephone apparatus Have yqu song poems? I have best proposi- made to your specifications. Lowest prices, high- tion. Ray Hibbeler, D Hs. 4040 Dickens Ave., est grade workmanship. Lee Bros. Co., 605 N. Chicago. Walnut St., Champaign. Ill. Song Writers. Wireless Amateurs. We are selling "Areogram" radio pads, one hundred sheets for twenty -five Song Writers. You cannot afford to miss our cents. Just the thing for keeping a record of proposition. Reference any bank or first -class or sent out. Send your orders & Co., messages received sheet music house. Warner C. Williams now. Only a limited supply. Agents wanted. Dept. R., Indianapolis, Ind. Sample 3 cents. The Arco Press, 45 N. Division Stammering. St., Buffalo, N. Y. and Stammering cured at Three pairs Imperial phones; moo ohms; pickle St- Stu- t- t- tering head band and cord. Very sensitive. 83.75 pair. home. Instructive booklet free. Walter McDon- not saustactorl. Bldg., Washington, D. C. Worth 5.8. Money refunded if nell, iii Potomac Bank H. Butterworth, toe Greene Ave., Brooklyn, N.Y. Collapsible Scenery for all plays. Amelia Galensi -One large piece Pa. Amateurs Tested (;rain. Philadelphia, tested galena. Only 15c postpaid. Each piece Telegraphy. goes under actual test before shipment. Radio and Testing Station, as Sturges St., Binghamton, Telegraphy (both Morse mad Wireless) Y. railway accotintini) taught thoroughly and N. quickly. Big salaries now paid. Great oppor- Knocked down variable cond for panel Est. 45 and cabinet mounting. You assemble and save tunities. Oldest and Largest School. at years. Catalog free. Dodges Institute, 5th St., money. .00t mid. 3 p 8r. 0005 mfd. Valparaiso, Ind. ßs.25. .00055 mid.. All postpaid. Also lplateong and short wave tuners. Write for circular. Photo Developing Richard Stowe, 6a3 Grand Ave., Dayton, Ohio. Mall me your next roll of films for develop- Wireless Course In ZS Lassons. By S. Gerns- ment and 6 prints for 25 cents. You won't be back, A. Lescarboura and H. W. Secor, E. E. sorry. Elmer F. Koehler, 1043 White -Rock Ave., Tells you everything you want to know about Waukesha, Wisconsin. "Wireless"-.-theory. practice and history. A clear, concise course on every phase of this Electrical Supplies and Appliances. subject. do pages -350 illustrations, 3o tables. Radium Laketon guaranteed to stone in the Flexible cloth cover. 75c postpaid. Stiff cloth dark, attach to electric switches, gas jets, key cover S1.a3 postpaid. Experimenter Publishing holes, etc., moo other uses. Send twenty-five Co.. hook Dept., 333 Fulton St.. New York. cent.. Agents loo per cent, profit. Radium New How to Make Wireless Receiving Apparatus. Products Co., 715 Monroe Place, Wes no pages, to illustrations. Only strictly modern Co. York. N. J. Fl, -ctro Importing radio apparat are described in this book and 231 -A Fulton St., N. Y. Experimental Electricity Couru in m Lessons. the illustrations and descriptions are so clear By S. Gernsback and H. W. Seto" E. E. A and simple that no trouble will be experienced course of the theory and practice of Electricity in making the instruments. Paper covered, ssc Gentlemen :- of experi- for the Experimenter. Every phase postpaid. Experimenter Publishing Co., Book Enclosed please find One Dollar. mental electricity la treated comprehensively In Dept.. 533 Fulton St., New York City. Ex eriment2 are described Trans- plain English. New How to Make Wireless Sending Apparatus. Ship at once one Skinderviken and explained and nearly every application of pub- 1áo loo pages. 88 Illustration.. Written and Button to Electricity in modern life is iven. pages - who mitter cover, 75e post hotted entirely for the wireless enthusiast p., Ilhutratlgna. Flexible cloth make his own radio apparatus. Con cover, lorss postpaid. Emote!. wants to paid; stiff cloth tains more information on "how to make it" 'neater Publishing Co., Book Dept., 233 Fulton Paper bound, Name tit New York City. than any other book we know of. s e postpaid. Experimenter Publishing Co., Miicellanaous, )look Dept., an Fulton St., New York City. Address II. Parodies on Toteet Songs. toc. Charles Just off tits Press. Design and Construction Dyne., Winchester, Ind. of Auction Amplifying Transformers (Radio and AudloFrequencp Types) By Edward T. Jones, City Akin Mtl for a stmp. C. E. Robinson, 1i A t' ,nut late Associate Editgr Radio Amateur News. Inn.. book that every radio "bug" should have. Writ Novelties. ten so you will understand every word. Price State Publishing Co., Book Relics, page catalog free. Gruis stn postpaid, Experimenter Indian M t, .31 -A Fulton Street, New York City. coo her,. Mukwenago, Wis. Dep to adverrùer,. You bend. by mentioning the ''Radio Amateur Neetu" wies wrimop

www.americanradiohistory.com 392 RADIO AMATEUR NEWS January, 1920 NAME ALS..4 'LV/JtN/3teUVtilAeA'aeAYeN W.VtUJWtllt.ytle,lüW:V/?a,^. ADDRESS STATE FILL IN THIS E L E C T R O IMPORTING COMPANY, COUPON FOR 23IÁ Fulton St, New York City. I enclose herewith 6 cents In stamps or e YOUR coin for which please send me your COPY OF latest Cyclopedia Catalog No. 21 con- Our New 176 Page Wining 176 pages, 263 Illustrations , Cyclopedia No. 21 and diagrams, Including Treatise on Wireless Telegraphy, and 20 IT IS WAITING coupons for your 160 page FOR YOU Free Wireless Course In 20 r U I size fac- lessons. l' simile of our catalog just as it looks when you get it

It A N 1 1 -2 INCH THICK WEIGHT ALMOST 1 -2 POUND 1.iN 263 Illustrations

A Few Interest- ..-- ing Things from Catalog No. 21 Treatise on Wireless Te- legraphy by H. Oerns- tatrRaErimenerand Amateur News- 13 big pages, 3 /nas- W', a; less oElPctrícal tratious. The Wireless Law of 1912 -all bout It. , ,, what you ola do and i what you can't. yclop` il How to receive and send Radio Ji messages. How far you can send menage.. t: (I/I`/ \) Table of wave lengths. of principal ti. R. a r1 foreign Radio high pow- (/, El, er stations. - How to melee time sig- \\ \,, nals by Radio. How to construct an amateur aerial. Cat How to use the teat buxrn. How to loin the 'Radio NO2 League of America" 6 FREE, including application blank. How telephone receiver. wound end tossed 1 '1\ 3 pages. 2 Illustration. 1 r Experiments with pony ' ! telephone receiver. With . / 6 illustration . Wireless de Morse. C lies sal, Nary. i Experiments with spark I 1 tolls, 3 pages. How to photograph elec- L. ° trical dlscbarg ` (sparks),

All about atnnse bat - /Si=K'a, ' I , .a r tories, h o w Io test then, recharging, eta.

T e e l v! _ a experiments, 2 I 'ly : pages 1 _ :. Ir /il1 \ /, Slow to make Selenium ((jj rYa .I' / Celle (Illustrated). / 8t with t,d w.o- FREE :v rv C,1/ : derful cycloge- II .aJ li _ dla-20 coupons for our i b 160 Page Wirele 1 Course in 20 Incas. '! / i' 3 5 0 illustrations, 3 0 0 Ra f aY. -% tables. Catalog explains ! how you can get this Coure absolutely t I 1,1=" - free. d' /i/[i/d!!l!t! \ - lI . kÌpqP- :' `t. IIIIIIIVII I(Illl "THE 'he ElpciYo Imnoa'fin Co. LIVEST 231 FULTON STREET NEW YORK EVERYTHING CATALOG FOR THE EXPERIMENTER' IN AMERICA" IN this cyclopedia you will find 116 pages E. I. Co. for quality and workmanship. Talkers, High Frequency Apparatus and all about radio. One of the greatest Other things you supplies, Heating Pads, Electro- magnets, catalogs of its kind in print. will find listed in this catalog: Electrolytic Interrupters, Bull- X -ray tubes, Telephones, Magnetos, Low You will find in it dozens of wireless in- dog Spark Coils, Chemical Outfits, Omni - Tension Transformers, Books, etc., etc. struments of the famous E. I. Co. make. graphs, Code Practice Sets, Telegraph In- IN A WORD THE MOST COMPLETE Remember always that this company was struments, Primary Batteries, Storage Bat- CATALOG IN PRINT '. the FIRST to make and sell wireless instru- teries, Solenoids, Hydrometers, Volt and ments, the first wireless outfit having been Ammeters, Batterymeters, Electrolytic Rec- rrl placed upon the market by them in 1904. tifiers, Rheostats, ELECTRO IMPORTING CO. Tesla Coils, Nickel Plat- FULTON The E. I. Co. knows how, because it has ing 231 -A STREET NEW YORK. N. Y. T the Outfits, Lighting Plants, Dynamos and o: experience. Others imitate but cannot equal Motors, Microphones, Detectiphones, Loud "Everything for the Experimenter" bill 4C. s,íraa;racra:h:fi . trati-slNgtlfi'eYll'nLYaVlfie`dFßhrilr%s\ír/etV%a\1YAlYaYRtinfAhYglYa\tYaYCAa:40YAíha\1iY9eYYeCTß\7"

You benebt by mentioning the "Radio Amateur News" when writing to ado, rtia,rs.

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10 t JIwUU Volumes HAWKIN HAWKINS: ' AWKIY HAWKINSr ' NAWKIN_ 'HAWKINS ¡d' EEEURIEAE= ÏFIEURIU IiEEUR, EUiRI Ettunt 3500 aunt t Flexible r' lisp GUIDE GUIDE GUIDE,i. GUIDE Guist, GUIDE ,Ql ? Pages ANA Covers - - toll _ . 4700 i'lq6'.; %"9 N° - Pictures r Handy --===------.., ,,, HICTRICITY MtuttNlNl _° A.C. :' = A.C. s RAILWAYS. MODERN $1 Per NAGNEEISN-" SYSTENS_ WIRING Pocket - DyIÌADS pfRRATI MOTION ' uno r INOUTTION gsl CIRCUIT,: POWER Of Volume MTORS YSTMS_ mRRNIS PICTURES OR,RÌN(IOy BREAKER STATIONS EIEGRIU Size 115 OYgaMOS - IStüt ORAtE NtAyÌRigG % TtUMOME . REI[RINCE ARNqURtS' tIRRot $Í Per THING TRRIES 1., MEMO IGNITION WINO FF ' "RK. INDES Volumes _ ; _.....-. 1 Month

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Just what you need to know to succeed in ELECTRICITY

EVERY electrician, every engineer, every mechanic should know READ about these wonderfully helpful instructive books, which give in THIS PARTIAL LIST OF CONTENTS 1 Contains 348 pages, 388 Illustrations. Electrical plain words a complete working knowledge of electrical engi- No. signs and symbols-static and current electricity -primary cells -conductors and insulators- resistance and neering in all its phases. conductivity- magnetism -induction cols- dynamo principles -classes of dynamos- armatures- windings- commutaUon- You run into some new electrical problem almost every day. The brushes, etc. Contains 348 pages, 394 illustrations. Motor information you need to help you in your every day work is in Noe 2 principles- armature reaction -motor starting calculations -brake horsepower -selection and m;Wlation of- dynamo and motors- galvanometers- standard cells- current measurement - resistance measurement voltmeters watt- meters-watt hour meters-operation of -dynamos -operation- of motors. etc: -- - Contains 300 pages, 423 illustrations. Dlstribu- No. 3 Uon systems-wires and wire calculations-in- HAWKINS side. outside and underground wiring -sign flashers-lightning protection- rectifiers-storage battery systems. eto. No. Contains 270 pages, 379 illustrations, Alternat- ELECTRICAL GUIDES 4 ing current principles-alternating current diagrams -the power factor -alternator principles- alternator These books place electricity at your /finger ends. They cover every Imaginable construction -windings, etc. subject, principle, theory, problem, trouble, and way of doing things electrically. Noe Contains 320 pages, 614 illustrations. A. C. Motors Every subject Is Indexed so that you can turn right to it. They are a study course 5 -synchronous and induction motor principles -A. C. commutator motors -induction motors, transformers; and a reference guide in one, written in plain every day language -no wasted words construction, connections. losses, what need to know -chock full of up-to -the- minute electrical knowledge. tests -converters -rectifiers. etc. -only you Contains 298 pages. 472 illustrations. Alternating The guides are a complete course in electrical engineering. They will help you in No. 6 current systems -switching devices -circuit break- every detail of the day's electrical work. You can't ask an electrical question that ers- relays -lightning protector apparatus -regulating devices Hawkins Guides can't answer, -synchronous condensers- indicating devices- meters-power factor indicators -wave form measurement -switch boards. etc. No. 7 Contains 316 pages, 379 Illustrations. Alternat- ing current, wiring power stations -turbines. Pocket -Size Flexible Covers management, selection, location, erection, testing, caro and repair -telephones, running. The books are small enough to slip Into your coat etc. 8 Contains 332 pages, 436 Illustrations. Telegraph ,[bal Electrical Men Say pocket- handsomely bound in flexible black covers. No. -simultaneous telegraphy and telephony-wire- You can carry each volume with you until you have less electric bells electric mastered Its contents. 3.500 pages of actual information - - lighting - photometry, etc. Helped Him Make Good Contains 322 pages, 827 illustrations. Elec- and 4,700 illustrations. Ones you see these books and No. 9 tric railways- electric locomotives -ear light- "It is only right for mo to recom- put them into actual use you will never again want to be ing- trolley car operation -miscellaneous mend for without them. Try it at our expense. applications- Al highly the Hawkins Guides. motion pictures -gas engine ignition- automobile self - they harp been or the greatest assist- starten and lighting systems. electric vehicles. etc ance to me In placing mo m my NO. Contains 513 pages, 599 Illustrations. present position as Superintendent of 10 Elevators- cranes- pumps -air com- Construction Department of one of NO MONEY pressors- electric heating -electric welding- THEO. Ohio's largest Electrical Companies. SEND soldering and bracing - industrial electro- 1 would like to see every man have bum,- electro plating- electrotherapeunc AUDE L set of Hawkins Guides." It will cost you nothing to receive these books -to look -X -rays, etc. & CO. them over them all the you can think of , Geo. Knecht, Columbus, Ohio. -ask Questions Also a complete 72 Ave. -oso them in your work-study them-pick up some 126 -page ready. Fifth In the Naval Electrical Dept. information that will increase your earning ability. We reference Index of the complete New York, N. Y. will strip you the entire set of 10 volumes entirely FREE. library. This Index has been "The Hawkins Guides are great Is a sign of our confidence in the planned Please submit me for help to This guides. Pure to render easily ne- me in the Naval Electrical gold does not object to being tested. Keep them for cessible all the vast infor- # examination Hawkins Department. which they cover von, sewn days and if you do not decide that you can't get thoroughly." C. J. Cornell, along without them, return Went to us and owe us malion contained In the Electrical Guides (Pelee U. S. Reoeiving Ship, Brooklyn, N. Y. 10 electrical guides. nothing. , SI each). Ship at once. pre - There When you keep them you only are over 13,- IO Superintendent decide to have to pay 500 cross refer- Held. the numbers. If utls balance on the easy , factory I agree to send you Sl "1 am now superintendent of the Vaymwditw f $1 00 ea month paid for.0Ú whist You Dunnville Hydro Use this coupon to get the books. It will pay you what you want within seven days and to further ki Ouieswee great many times over , you 21 each month help to me in holdingdlacr down a re- to know in- null until paid, sponsible pontlbn." straitly. , W. E. Swarts, Dunnville, Ontario. THÉO. AUDEL & CO. BIgnature Wireless Operators 'T have worked wireless for ten 72 Fifth Ave. New York, N. Y. le Occupation years -but I wish I had theeo book. years ago, as they have saved mo a Employed by great deal of trouble." H. Marshall. Steamer M & B No. 2. Rest dance Walkerville, Ont. AP ir

Reference . A.N. J.m.

You bent-lit by nrantion roll file "Radio Anmteur Netts" ruhen writing so advertisers.