Evening Star Newspaper, May 27, 1923, Page 20

“ oy Amplifier Tube Functions In Broadcasting Explained Likened to Miniature Transmitter Within Receiver in Radio — Tube Detector’s Influence in Long-Distance Signals. BY PAUL GRIGGS. Tr we replace a erystal detector in a recelver with a tube detector we invariably obtain stronger or louder signals from .passing radio waves. We are also enabled to hear the pro- grams broadcast by distant stations located too far away to be heard with a crystal g If we asnc plifier tubes we obtain signals strength. We theh grams broadcast b, perhaps 1.000 miles 2,000 or more miles away. We way that the tube detector more “sensitive” to passing broadeast waves with which our antenna and receiver circuits are adjusted to “res- onance” than is the crystal detector, and that the amplifier tube or tubes increase the sensitivity of the de- tector tube. The logical inference is that the detector tube abyorbs, or causes to be absorbed, relatively more of the elec- tro-magnetic energy from passing radio waves than the crystal is cap- able of absorbing and that the addi- tional amplifier tubes, when used, cause still more energy to be ab- sorbed from the passing waves, From what other possible energy mource could the stronger or louder speech and music come? We quite naturally assume that the signal strength must all be extracted from the passing radio waves; that the full volume of the Incoming speech and music is all “picked out of the air.” d Power of Antenna System. - . As a matter of fact. however. nelther the crystal detector nor the tube detector nor the tube amplifier have anvthing whatever to do with the amount of energy extracted or rbed from passing ether or radio It is our antenna or collector and that.alone; which ex- bsorbs electro-magnetic energy f P ng waves, nd the same amount of energy is absorbed from passing waves entirely regard- less of whether a crysial or one or more tubes are employed in the re- ceiver. A properly designed low-resistance Teceiving antenna system will absork more electro-magnetic speech and music energy from passing waves than will an Improperly designed high-resistance antenna system The antenna circuit transfers its energ to the receiver circuits and an ient antenna il transfer more ¥ to the receiver than will an in ent But this con- dition appl iess of whether we em stal detector in our receiver, or a single tube detector, or & tube detector associated with one or more amplifier tubes. It is clear. then, that when we em- ploy tubes in ou eceivers there must be available some local power which produces the equiv of human speech, mus and other sounds. and that this local power is lacking when we employ a crystal. This is actually the case. Thne local auxiliary power is in the tubes within our receivers The detector tube in our receivers with its circuits and batteries, con- stitutes a local miniature electric power plant. Likewise, the amplifier tub. tutes not only a miniature power plant within itself, but when functioning as an amplifier it com- prises a miniature transmitting sta- tion within our receivers. It is not to be wondered at, then, that we obtain loud signals hear distant stations when we employ tubes, especiaJly amplifier tubes Crystal Detector Minus Energy. The crystal detector possesses with- In itse bsolutely no energy or power whatsoever. It is entirely de- pendent for its functioning on the encrgy of the incoming signal oscil- lations and its manner of functioning actually wastes at least half of the coming signal energy by suppress- every olher energy alternation of the incon & wave. The tube detector, hand, not only causes virtually all of the incoming signal energ: to be utilized for producing sound telephones, but it also adds its own electrical energy to that of the in- coming signal. thereby strengthen- ing the signals, as described in my article of May 13. Obviously, therefore. we should al- w s obtain signals of at least double the strength for the sume distance, and we should be able to hear stations “«t least twice tne distance when w one or more am- the detector tube of still greater can hear pro- iate with away; possibly stem, consti- electric on the other stations situated | and can | in the | employ a single detector tube in place of the most sensitive crystal. When we add radio frequency am- plifier tupes to our receiving equip- ment we transplant, so to speak, the distant broadcast transmitter in miniature form directly in our re- celver, As a radio frequency amplifier the tube simulates a “relay” or “way sta- tion” for distant transmitting sta- 1 tions. Sensitivencss of Tube a Factor. The sensitiveness of the tube as a radio frequency amplifier is equaled only by its marvelous versatility. It ! would 'seem to be only necessary to endow 1t with reason to make it { human. It suffers the distant broadcast sta- tions voice, music and other electro- magnetic sound cquivalents (although fhey may be so,extremely weak when impressed upon it through the an- tenna and receiver circuits as to be rely perceptible even to itself) to {moldits own comparatively vigorous cnergy into their corresponding fre- quency form, and qualities. It strengthens these equivalents enor- i mously; perhaps 1000 times, possibly 20,000 time_or more. It actvally cieates human speech, for example, out of something that was incapable of producing human speech When frequency used as a radio w mmodate - and amplifier it will acc strengthen incoming signal oscilla- tions so extremely weak that even our marvelously sensitive detector tube will not accommodate and rec- { tify them into audio frequency pulses. This "is the principal reason for utilizing radio frequency amplifiers— to increase the strength of weak in- coming radio frequency oscillations sufficiently to cause the detector tubes’ own energy in turn to accommodate them for rectification purposes. When we employ radio frequency amplifiers in our recelvers, therefore, the tubes circuitc are always asso- clated with the eeesiver circuits in nuch a way that the incoming signal oscillations are impressed on the in- put circuit of the tube. The .radio frequency amplifier accommodates them, strengthens them. and delivers them in the identical form in which received through its output circuit. As many as three radio frequency amplifiers may be used to advantage in receivers. If three are used the incoming signal oscillations are many times as strong by the time they reach the detector tube as they would be if only one were used. Not Producer of Sovnd Wavex. Radio frequency oscillations electro-magnetic undulatory move- ments in the ether. hr reversals of current flow in_electrical circuits, of an extremely high order. It is be- lieved they are incapable of produc- ing sound waves, or if they do the waves are of such 1 high pitch as to be inaudible to th| human ear. A broadcast station transmitting on a wave lensth of 40] meters, for ex ample, creates ether waves the fre- quency of which yre 750,000 cycles per second. Theis corresponding os- cillatory currents in our receiver and radio frequency amplifier tube eir- cuits before they reach the detector and likewise reverse their direction 750.000 times per second The range of frequencies which may produce sound waves audible to the human ear are from 10,000 cycles for sounds of extremely high audible pitch to about iifteen cycles for sounds of extremely low pitch. The function of the detector is to rectify the oscillatory or alternating currents of these extremely high fre- quencies to direct current pulses of frequencies corresponding to audible sounds of the general order of 1,000 cycles. are Effect of Frequency Amplifiers, When we employ audio frequenc amplifiers with our tube detector, either In conjunction with or without the radlo frequency amplifiers, we transplant, so to speak, the distant broadeast performers in our receivers in much the same manner that we transplant the distant broadeasting transmitter when we employ radio frequengy amplifiers. These amplifiers function to in- crease the strength of the rectified pulses of audible frequency pulses of voice and music equivalent to cur- rents in much the same manner that the radio frequency amplifiers in- | crease the stréngth of the radio fre- quency oscillations | The basic functioning of all three electrode tubes is identically the The electrical circuits asso- clated with the tubes determines whether they will act as radio fre- quency amplifiers, detectors, or audio frequency amplifiers. same. Century Pre RADIO GOSSIP AND NEWS Radio enthusiasts among the Army, Navy and Marine Corps officers sta- tioned in Washington have organized the United States Radio Assoctation and elected Lieut. Col. F. P. Jackson, Quartermaster Corps, as president. Other officers are Capt. J. T. Tomkins U. 8 N, vice president, and Capt 2. B. Connor, secretary. The club has for its object the education of commissioned officers in the radio science. Approximately 100 officers have enrolled, in addition to some civillan experts, admitted as associate members. Maj. Gen. George O. Squier, of the - Signal Corps of the Army, gave the first practical talk on radio before the association. As a result, plans have been formulated for a lecture course on the various phases of the radio science. Strange Experiemce at Seabrook. The story relating to “dead spots,” which appeared in this column last Sunday, prompted Mrs. George E. Weed of Seabrook, Md., to write the following letter to the radio editor: “We have all been reading your news notes and have similar_experi- ences as you have noted. For in- stance, the Baltimore station is rarely lheard. We live between the Pennsyl- vania railroad, one-half mile north of us; south of us one mile is the pow- crful trolley line of the Washington, Baltimore and Annapolis electric line. The Ardmore power station is less than four miles away. We seem to hear it roar here at times. The sky- line_was aflame with vivid electric «narks one night in April. Some Zolks here thought the world was coming to an end. Well, we wouldn't try the radio that night! “When we did hear Dr. Wood's Church of the Covenant we imagined the reverberations of his voice up in the arches of the edifice, yet I read and saw the picture of the set in the basement. _Sometimes the _voices cound muffled, no matter how sharply tuned. Then again, we don't get the enunciation clearly. WOC at Davenport, Palmer's school, sounds like ‘farmers’ and WDAP station, the Chicago Board of Trade on the Lake Hotel, sounds like ‘Drake’ Hotel, we thought, until we saw the names in print different.’ Physiclan Summoned by Radio. The steamship West Cahous, lying at anchor in Baltimore harbor. about nine miles from the city, needed med- ical help at about 3 am., recently, and needed it quickly, says the United States public health service. A member of the crew had fallen into the hold and had hurt himself serlously. So the captain of the ship zont & wireless broadcast asking help. The “call was picked up, not in Baltimore, nine miles away, but at Cape May, N. J., about 100 miles due east of Baltimore. As Cape May was separated from the West Cahous by parts of New Jersey and Delaware and by the eastern shore of Maryland, not to mention Delaware and Chesa- peake bays, no direct help from it ‘was possible. | But the operator was on the job. Promptly he consulted the long-dis- tance list in the Baltimore telephone directory and called up the residence of the public health service surgeon in charge of the Marine Hospital in | Baltimore—100 miles to the west. The surgeon, roused from sleep to receive the message, asked him (o radio_cer- ergency treatment to the Cahous, and fo direct the captain te send a boat to a certain pler in Balti. more, where he would find & surgeon Waiting to go out to the ship with him. ~And so, in the middle of the night, in less than an hour, a wire- ess-controlled sea-going ambulance, carrying a public health service officer. reached the side of the injured sallor and brou; lor = ought him later to the P'r. Meet Tube Supply Demand. 1ans for meeting the co 2 demands for tubes were revealod 1 a letter from Gen. J. G. Harbord head of the Radio Corporation of \merica, made public yesterday by the National Radio Chamber of Con. merce, which, following complaints of & shortage, s conducting a nation- wide survey ‘of the tube supply, i r;; Harbord, responding to~ the chamber's. request for a statement ex.. plaining the shortage, transmitted through the board of governors, said o (Corporation ordered es for of ‘Apcll. -~ OFf this number: sogoin were of the dry-cell type and 200000 of the storage-battery type. ¢ was the policy of the - poration, Gen. Harboard saig. 10 Cree to the public immediately the henefi of Do Jdevices as soon as they are . citing the 2 action in'placing the UV 198 des ome tery tube on the market as soon as a sufficlent number of tubes were avall: able to make_even small deliverioy Gen. Harbord asserted that the cor- poration expected to follow its stand. ard policy of building up production and reserves of this type of tube based upon the public demand; that during the month of April and the first week In May it placed, approxi. mately, 75,000 of these tubes on the market, and that further increase: production will depend to a large Ex- ent upon the rate at w tubes are absorbed. 2 ekt e Radio Corporation, added Gen. Harbord, hus laid down & wacour tube production schedule for a period of six months, beginning May 1. which coatemplates delivery to the i 8 . THE SUNDAY STAR, WASHINGFON, D. C. MAY 27, 1923 PART 1. LOCAL STATIONS. NAA—Naval Radio Station, Radio, Va. (435 Meters). 10:05 a.m. and 10:05 p.m.—Weather bureau report. WDM—Church _of the Covemant (360 Meters). | a.m.—Morning service; by Rev. Charles Wood, pastor. S p.m.—Evening service; sermon by Dr. Wood, en “Decorated ‘Graves and Dedication Day Tasks"; evening choir of 100 voices. 11 sermon WJH—White & Boyer Company (273 Meters). 8 p.m.—Services of the Vermont Avenue: Christian Church; sermon by Rev. Earle Wilfley, pastor, on “Paths in the Desert”; "special music by mixed and male quartets and chorus, led by William 1. Bralthwaite. DISTANT STATIONS. All Programs Scheduled for Eastern Standard Time. WEAF—New York (492 Meters). 2:30 to 3:30 p.m.—Interdenomina- al services, under the auspices of ew York Federation of Churches. b Musical program. Organ recital. o= S WIP—Philadelphia (509 Meters). Services of the Holy Trinity Memorial® Chapel. 1 to 2:30 p.m.—The Ben Stad Little | Symphony Orchestra. WHAS—Loulsville (400 10:57 a.m.—Organ music. 11 am.—Services of the Methodist Church. Metern). | & Trinity | WEBAP—Fort Worth (476 Meters). 12 noon to 12:15 p.m.—Services of the First Methodist Church. 6:30 to 6:45 p.m.—Base ball letins. 7:30 to 7:45 p.m.—Base Im}l scores. 9 to 9:10 p.m.—Final sporf neview. bul- WW.J—Detroit (516 Meters). 11 am.—Services of St. Paul's|C ——— e e corporation of no less than 2,000,000 tubes of the storage battery and dry battery types. ; Should sales of tubes during the coming months indicate that the above figures are too low, Gen. Har- bord explained, the corporation fs prepared to_ increase further its pro- duction orders, it is our policy and aim to supply all the tubes which the market requir Widespread Interest in survey has been aroused, to I'resident Willlam H. Davi. n(_lhr chamber. A report on the question- naire sent out nationally by the cham- ber's board of governors will® be made public soon. Can Reduce Interference. Up to a few years ago radio com- munication was for the most part carried on from a transmitting station to one recelving station; this is “point- {§ to-point communication. There wer on a few special kinds services, such as time and W signals, In which messages mitted by radiotelegraph from statlon were received by a cor able number of receiving | However, signals were transmitted | from a transmitting station in every | direction, and could, if desired. be received by any receiving station located within a certain distance, re- gardless of its direction. A compara- fively small number of wave lengths was sufficlent to take care of traffic requirements. Praetically all radio communication in the past has been carried on on wave lengths above 200 meters, according to F. W. Dun- more and . H. Engel, radio experts of the bureau of standards With the development of radiotele- phone transmitting apparatus, the transmission of the voice or music broadeast by radio has assumed an important place in the radio field Radio waves which are transmitting the voice or music wide band of wave lengths than a “sharp’ wave transmitting radiotelegraph nals. Because of this great in- crease in a kind of service which requires u wide band of wave lengths there is already comsideruble inter- ference among broadeasting st and between broudcasting and radiotelegraph station These authorities state that point-to-point communication the are two important ways of reducing such interference; that is, to direct the waves radlated from the trans- mitting stations in a row beam toward the recelving station, and to | use -short wave lengths, which are not at present employed Some .English investigators ha I recently reported on the results their Investigations on dire short-wave transmission Experiments have recen conducted at the bureau ards on transmitting ap ploying electron tubes, mits a directed beam of and emy waves as meters. This system, ti substantial relief from difficulties. Tt also_hus tary applications. The ar Dbeen used for communication by radiotelegraphy and radlotlephony. In the experiments at the bureau of standards a reflector has been used consisting of short parallel vertical wires arranged on a frame shaped like a parabola. This reflector acts much as an ordinary mirror would for light waves. The radlo waves are, in fact, the same kind of waves as light waves, but of considerably longer length. Forty vertical wires were used and the generating set, with fts small antennu, was placed at the focus of the parabola. Each wire was tuned separately to ten meters by ad- justing its length. It was found that about 75 per cent of the radiated the tube | according s R: D trans- | one | 1€ ider- | te w w ot tive been | stand- radio waves short as te opera c | purpose where it is used. |can be easily adapted to any speclal | requirement. have a special classification, such as a radio classification, so arranged that it will fit conveniently into a library ey classification is al- In th ion the number 621.384 represents radio communication, and the classifi- cation where the Dew this number. reau comparatively erial is iclent to use only the nine main which, number 300" apparatus orgal into | represents using ab of Cathedral. 4 p.m.—News WLW—Cineln: BY RADIO TODAY Schedule of Wireless News and Entertainment. Orchestra. il (390 Meters). RITES FOR MAJ. DUNCAN. Services With Honors at Arling- ton Cemetery Tomorrow. Funeral services for Maj. Thomas Duncan, Alr Service, who was killed in an airplane accident Friday after- noon, will be held at the Arlington Natlonal Cemetery tomorrow after- noon, at 2:30 o'clock. Burial will be made with full military honors in a 11 a.m.—Services of the Church of | grave about 100 yards southeast of the Covenant. WGY—Schenectady (380 Meters). 9:30 am.—Services English Lutheran Church. 3 p.m.—WGY Symphony Orchestra. 6:30 p.an—Services English Lutheran Church. of the of the WJZ—New York (455 Meters). 10 a.m.—Services of the West End Presbyterian Church. 7 p.m.—'The Annalist.” 7:15 by Ponch 7:45 chestra. 9 p.m.—Concert under the manage- ment of the Betty Tillotson concert ureau. p.m.—"La Gioconda,” p.m.—Hotel gra; felli. WSB—Atlanta (420 Meters). 1 a.m.—Services of the First Presbyterian Church. 6 to 7 p.n.—Sacred concert. 8:30 to 10 p. m.—Services -of ti Wesley Memorial Church. WGM—Atlanta (420 Meters). 4:30 to 5:30 p.m.—Musical program by Atlanta artists. 10:30 _to 11:3 ignor E. Volpi. KDKA—Pittsburgh (326 Meters). Services Breeze Presbyterian Church. 2:30 p.m.—Bible story for the chil- 10 a.m. ren 1:45 Quartet. 3:45 adyside Presb: 5:05 p.m.—Bas 0 p.m.—Concert of the p.m.—Christian Church Male p.m.—Vesper services of the yterian Church. e ball scores. 6 p.m.—Base ball scores. 6:30 p.m.—Services of the Calvary Presbyterian Church. KYW-——Chieago (447 Meters). 10 a.m.—Servi; hurch. 3:30 p.m.—Studio chapel services. ‘hicago Sunday Evening 7 p.m.— lub Services. of dy In use. prepared undards is really a subdivision of For the radio classifica- tion the abbreviation “R” is suggested to_represent There has recently been issued Bu- 138, the of Standar ggested Deci adio Subjects ewey System.” :ld_of radio hich subdiv This nded to be is and to not sacrifl heoretical refl In an org: to be in R nd e zations it such detafl clec pr erative action of classification reviated hich Is suitab] ify. ctive nd th Persons ork will stderable interest ircul purchased for 10 c perintendent ment Standards ¢ printing All Sizes at the It resistance neiples of ces of particular libra: is convenient Dewey classi at’ the bureau number 621.384. ds Circular No. mal Classification An Extension of t! In the classification given in this publication the general communication is_di- vided into nine main class w required cs, each ided as minutely classification is f; pre-eminently practical €ess to any = useful nent zation in which only a small amount of mi classified it may for cxampl reprse quipment.” may be d us “R34 tron tube couplf t “In lary 8" or super-rege electron tubes.” is glv organizatio le for {having & moderate amount of mate- rial to clas v S publication of co: r No. 138 can nts from documents, gove office Reliable Dealers. First First Commodore Or- Point the Central It is flexible and radio “mplifiers -l An engaged in radlo A copy of Bureau the & the Lee Manslon. The honorary pall-bearers will be Col. George F. Baltzell, infantry, Maj. Gerald C. Brant, Alr Service, Maj. J. W. S. Wuest, Air Service, Maj. Henry T. Burgin, Coast Artill- ery Corps, and Maj. Frank Thorp, jr., fleld_artillery, all of this city; Ma Hanr{ B. Clagett, Alr Service, of Langley Field, Va., and Dr. Jesse L. ‘Wagner of Reading, Pa. WAR RECORD HONORED. | Business Men Present Gen. Bell, | Retired, $30,000 in Cash. ‘Word has reached here that Maj. Gen. George Bell, jr, U. 8. Army, retired, now residing in Chicago, has been pre- sented with securities valued at $30,000 by a group of business men of that city in recognition of his military services. During’ the world war Gen. Bell com- manded the 33d Division and also the 6th Army Corps in France, and most of the donors of the gift served under his command. The presentation took place at a banquet given in honor of Gen. Bell in Chicago on the 15th inst. —_— CLASSES TO GRADUATE. Graduating exercises of the Army Medical School and the Army Dental School at Walter Reed General Hos- pital will be held in the audftorfum of the new Natfonal Museum Friday afternoon, June 8. The graduates wiil be addressed by Acting Secretary Da- vis and Surgeon General Ireland. ' Large Soft Crabs..$1.00 per doz. Hard Shell Crabs.......50c doz. Crab Flake .... 60c b, Lobster ........ ve....50c b, Sea' Scollops .............$L00gt. Fish Prices Always Low EACHO & COMPANY 21-22-23 Muniecipal Fizsh Market Phones Main 6176 and 9510 nd he by i ry to - of of he of as n- Company. T be he ge n- en ns m be ) S T If the to I N N I N G now ma Colbert Glad to MAURICE downspouts need ing. now's the right time order Summer rains will reveal = the weak AT ettty 0L RN Z 5 £ [T rooi, gutters and rep: the job done. y obviate need for extensive replacements. * fYou' can depend upon to do strictly re- liable work at Fair Prices. estimate. J. COLBERT Heating—Plumbing—Tinnin 621 Street Phone Main 3016-3017 LT U R LTV energy could be confined within an angle of about 75 degrees. This_ apparatus i desciibed in scientific paper No. 469 of the bureau ¢ standards, entitled “Directive Rudio | Transmission on a Wave Length of Ten Meters,” by F. W. Dunmore and F. H. Engel. Coples may be obtained from the superintendent of docu- ments, government printing office. | Washington, D. C. The price is 10 cents. Decimal Classification Method. During the past few years the field of radlo communication has grown very rapidly, and a very considerable | number of different kinds of appara- | tus and, methods are now employed In organizations actively engaged in radlo work, such as manufacturing., | operating or selling companies, and {radlo research laboratories, and in large libraries, there ig a real demand ltor convenient and comprehensive | methods of classifying the consider- able volume and variety of printed matter, books, specifications, draw- ings, references, and other radio ma- terial which is constantly accumulat- ing. A -good method of classification Dby subject makes it possible to place the material covering related subjects | near together in the file or on the shelf, instead of arranging the ma- | terial simply In the order in which | the varfous items are received. | | The only valuable knowledge is the available. To be avaflable it must be so cssified that it can at once be found. It is often much easler to- hunt up a desired fact anew than to search for it among a mass of ma- terial which is unclassified or poorly classified. Several years ago the staff of the radio laboratory of the bureau of standards felt the need for a suitable classification In connection with its own work. After some trials, it ap- peared that a decimal system of clas- sification would be very useful for this purpot Persons, connected, with library work are’ familiar with the Dewey | decimal classification, which assigns a classification number according to subject to every book which may be found in a library. The Dewey clas- sification has been successfully used since 1876, 'The entire field of human knowledge is divided by the Dewey classification into nine main classe: and each main class is subdivided as minutely as may be required for ihe Do You Want to Sell Your Auto? The quickest way is to advertise it in the Clas- sified Section of The Star. Describe it fully— make, condition, equip- ment, price, etc., and the replies will come rolling in. Star Classified’ Ads bring such satisfying results that every day The Star is required to print MORE of them than all other, combine “Around a Star the papers here d. the Corner” Is Branch Office quarters. T A [ TR It will be known as “SHR INE” This central office will connect with: Shrine Housing Bureau Shrine Registration Bureau Shrine Transportation Bureau Shrine Information Bureau Visiting Temple Headquarters Almas Temple 1923 Shrine Committee All Other Shrine Activities tions be made as brief as possible. Announcing a Special “Shrine” Telephone Exchange Tomorrow (Monday) a special exchange for service during the great Shrine Convention will be opened by the Telephone Information as to the movement of special trains may be ob- tained from the Transportation Bureau. Information on parades and all other Shrine activities may be obtained from the special information switchboards. Ask the operator for “SHRINE” from any telephone, and you will be ‘connected with any of the above bureaus and head- In order to avoid congestion of the telephone system during the Convention, it is urged that telephone conversa- The Chesapeake & Potomac Telephone Co. I miE T LA TR T T The addresses of registered visiting Nobles mayv be obtained from the Registration Bureau.