The Sunday Oregonian. (Portland, Ore.) 1881-current, August 13, 1922, SECTION FOUR, Image 64

The Sunday Oregonian., August 13, 1922, SECTION FOUR, Page 8, Image 64

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Newspaper Page Text8 II V IMS (M i BT SAUL EMANUEL O you know tha difference be- een a "volf and ao' -am pere" 7 Thea two terma. which are ued the measurement of electricity Knd electrical circuits, often have been confuted by the norlce In the radio same. Many think they are wo names for the same thins;. The terms "toll," "ampere." "watt" and "ohm" are being en countered dally by the thousands Eho hare taken bp the radio as a eana of amusement or entertaln ent. y A knowledge of thee common Mectrlcal terms ahould prove of krreat Interest to these persons and there who are reading of the radio rniraclea nearly every day. ho volt la the unit of electrical rresaure. r rather, difference in ressura. Wherever there happens i to be a difference i.: preau-, ' whether I; be in water or electricity. there wll! be a movement or flow. If thf presure of one end of the electrical circuit Is greater than that of the other end. whit is known a current of electricity will flow. This wilt flow as Ionic as the difference of pressure exists. The voltage Is the amount of difference; In the pressures. When the current flows it must have a certain strength or amount of flow. This strength is measured In amperes. If the pressure be tween the ends of the circuit Is raised a larger amount of current will flow. Thus, by increasing the pressure, or voltage, we also In crease the amount of current or am pereage in proportion. In all electrical conductors there is something which holds back the flow of current or offers resistance to it. The amount of the resistance Is expressed in ohms. The relationship of these different electrical factors is expressed In what Is known as Ohm's law. The pressure In volts divided by the resistance in ohms will equal the amount of current In amperes. If any two of the factors are known and the third is desired. It can be easily obtained by using this formula. When we have a certain pressure setting a certain amount of current to flowing an amount of power Is being expended. This power Is ex pressed In watts. Tha watt is the product of the pressure, multiplied by the amount of current. With this formula, as In the other. If any two of the fsctora are known the third may be found easily. , "ADAPTER" MAKES PHONE WIRES SERVE AS ANTENNAE FQRRADIQ RECEIVING SETS Puget Sound Telephone Company of Everett Offers to Patrons Use of New Device Invented by Seat tle Man Construction of Aerial Wires for Radio Reception May Be Made Unnecessary. RADIO QUERIES AND ANSWERS Idttor Radio Waves and Ripples: X. Would yo a kindly oalwe me hr ndtcc a hookus f some STra le nroea lAe tumnc of a shert wave re- aerative set eoasistlng of two v rlo neterev a vmelo-coopier and one stase of d!o frequency! 1 Would shortening the distance he ween the rotors sad the staiors ot the arlometers helsT a Contd a variable condenser be uee.i a lacreeee the elreoslh vf the aisaa'.s IB aw circuit ana so. wot W. eV. Chit wood. Or. F TOUR" regenerative set is cor j rectly constructed. It should be ver- sha.ro In t'.a tuning. Sug- st that you place a variaote cui. Is thts ljrp of antenna suitable for raJU.pno:ie? ft O. U . Portland. Or. 1. The rotor is generally three Inches thick and three and three quarters inches in diameter. The small ribs at the edge of the rotor are made 1-1 Inch high and 1-1 inrb wide. For a plate variometer 4i turna of No. IS aire wound on the rotor and the same on the stator wi.l give you a good combination. For the grid variometer wind the rotor with S turns of No. 22 and about the same on the stator. 2. Any blade switch of 0 am peres capacity will do very well. 1. The V-shaped antenna should enser in h. aer... circuit in series , HZ fee Hong Con- ith the primary ti me j thl!, iead-ln- wire to the bottom oupler. This will sharpen the tun- I of ,h, v . - ..;i...kt- " ! i constaeraoiy. i 'o. Such urocedure would tend ! o do the opposite. J. .v condenser does not Increase 1 strength of the signals. The use f one la the circuit will allow a .ner adjustment of the circuit's ca-acity. .tllor Radio Waves aad Ripples: I. What can be dona for a rnea te hookup that woa.d stop howling on o meters? My srid and p:ate leads are .t rlnae ,;oIher. 1 think that the wling lavraued by the Cioee coupling ' my variometers. ; Would a tube that works on more B ' tvattery howl more than a tube that m less? . Woo d a bad -B- battery cauaw ime bowilng? 4. In Armstrongs super-reeeoerattve eok-op. should the eeconoarv ot ID eond counter where tnefirimary is ran- cted to the srld of the second tub, be r-p4 as well ee having a vartaDie cod cev across it T 5. Kow mane tarns on both for 15 to V meter workT Does the above hookas ampUfy adtophose as well as spark station? t. May the two lubes In the atmve oknr be lit by the iuii "A" battery? S Can seod reaalts be obtained ea t. W. with aa ordinary areuad laataad ot eovaterpoiee? T. X. X-, Portland. Or. 1. Tha causes of bowling and Its Umlaatlon ara taken up fully In an rticla in thia week's radio section. Not always. The howling Is arely caused by the tuba Itself but due to poor battery, etc . Tea. 4. No; tha inductance are fixed. 5. Tha primary coll consists of J 00 tarn, tha secondary of lzi9 urn a. . Tea. . 7. Tea. t. Tea. Good reaults can often be btalned with a regular ground. It a a matter of experimenting to see vhether the ground will work as Ivell as tha counterpoise. Miter Radio Waves and RiPeUs: 1 Would It ba ail right If I need l-md speaicer with a varuora tube, s.d condenser ana tatting eoliT 3. If en. would It b aU right te ue ox Colainbla Orafonola aa a lend email . How far can I be able to hear with V loop aerial tuning ceil and fixed eoa- siieirr A. ras, Laanton. ur. X, It la doubtful If you will be abla a srt loud enough signals out of a -ud speaker using only one vacuum a be. Tha loud speaker works best rhen at least two stages of amplic ation is used In addition to the de eetor. If you can ret signals loud nough from your telephone recelv rs to hurt your ears when you are veartng them, you may bo able to s tha sound chamber 01 tna poon graph as a loud speaker. 1. The loop aerial can only ba used uccessfuily with a set consisting f at least two stages of ampllfica tdttor Radio Waves and Rioplea: 1. Could any of tae western broed aatir.c ataiioiu be picked op by a station rate! at Faedlatoo with the almp.e re nerattve receiver described In The ren:an ef Jane 4? 2 Wouid a (rid leak Improve Hie set i la the wire from the "A" batterv the around connected with the wire t:n from the phones to the variable ndenrT K. Miava.e. ma 1. Picking up the western stations rom Pendleton will depend on many ther conditions besides the receiv es set alone, such as heighth and nd of aerial, type of ground used, lose proximity of power lines snd cal atmospheric conditions. I. Yes. the grid leak is necessary cr the successful funellon of the acuum tube. . Yes. Kdttor Radio Wtm and Rtppar 1 When I connect mv receivers to the aertal and the around there Is a contin uous rirctne. What la this and what is the cure? 2. Please send me a hook-up of two honercomb coils 11-plal tariabie con denser, and a eryjstai detector. 1 en -cioe stamp and envelope for same. a Could I receive from Portland with this set; The distance la -S miles. 4. Can a sood varlo coupler be made? If so. how. aod how sha:l I hook -it up? A. E. O., Forest Grove. 1. What you hear Is the induc tion set up by nearby power lines. The only way to overcome this Is to place your lead-in wires as far away from the power lines aa possible. I. The hook-up has been mailed to you. I. It Is doubtful be able to hear 25 miles with your set. Would advise the use of a good loose coupler Instead of the honey comb coils, as the fixed colls are not suitable for crystal detector cir cuits. 4. This column Is too limited in space to take up the construction of a vario-coupler. It will be taken up in the radio aection In. a future issue. . : - , ,si . , ,,. '7?:.,' I ' - . : '""!' V" ' K"" ' i I sLljiLMawawwawawwwswaaa I lavealor Wlghtaaaai llatealng la by wee- of his radio adapter while aa ordinary conversation la going; on over the telephone. i it is best to mount the binding posts cn the rear of the panel on fiber strips. - The large meter holes may ) be drilled with a regular expansion oit. . First smooth the wood off with I sandpaper; then purchase a pint of i dark metal primer, such as is used I by automobile body painters. After V U U llSLVe O Li a-l UCU LUC ll liuoi througrh cheese cloth, give the panel a good, heavy coat and leave it for a day to dry. Then rub it with a very fine sandpaper, always rubbing it in the direction of the grain. Now give the panel another coat of primer, applied in a room where no dust will fall upon the panel. This second coat should be applied very thinly and evenly. A wooden , panel, is not recom mended for an amplifier. 71 Radio Notes. HOOKUP OF NEW ARMSTRONG SYSTEM IS VERY SIMPLE DEVICE Super-Regenerative Receiver, With Which Amplifications of 100,000 ' , Can Be Obtained, Not Difficult to Install. PIXIKT S Wash.. of aerl, Editor Radio Waves and Ripples: 1. I have made a variometer with B0 turns en the primary and i'S on the secondary. Will this do with a crystal receiving set for radio phone work 7 2. Which Is the better, an aerial grounding switch or a protective device? S. txes It spoil a tuning coll If the enameled wire gets loose? 4. Some dare I hear Portland well and other davs I can barely hear the sta llena. What does this mean? W. W., Corvallla. Or. 1. Tou wil have to have the sam number of turns In the sec ondary or rotor coil as you have in the primary or stator coll to get any results. 2. The protective device is con sidered the best, as It works auto matically. I. Yes. This will cause slight change in the tuning when the wire vibrates. 4. This Is due to the changing atmospheric conditions, which are never the same two days in succes sion. However, such difference in the conditions will not be so no ticeable during the winter months. IXIKT SOUND BUREAU. Seattle, Aug. 12. Construction ial mires for radio recep tion may be maife unnecessary and the questionable use of the electric light and power wires prevented by means of an "adapter" that can bo janacnea to teiepnsne boxes, wnicn will make telephone wires serve aa safe and certain antennae for radio receiving sets. Use of this adapter and connection of a radio receiving hether you will! set does not In any way Interfere with regular telephone service. The adapter is the invention of Merle J. Wightman. an electrical engineer, who is president of the Seattle Radio association. Its serv iceability has been worked out and proved In collaboration with Major Garrison Babcock. Inventor of the telechronometer. who Is also an officer of the radio association. Everett, scene of the first experi ment In measured telephone service by means of the telechronometer. Is also to have first opportunity to listen In on radio over telephone wires by use of Air. Wightman's de vice. The Puget Sound Telephone .com pany of Kverett. with the conaent of the state public aervice commis sion, is offering the use of the radio adapter to all of its patrons. There Is, of course, nothing compulsory about the matter." It is a service without profit to the telephone com pany. Telephone subscribers wish ing to have the adapter installed have to become members of the Se attle Radio association. ' paying the regular dues of J5 a year. The tele phone company, by contract with the radio association, undertakes to install the adapter on the request of any subscriber and to see that all users of the adapter are supplied with the weekly bulletin covering the broadcast programmes of the ensuing week. This is done without cost to the subscriber beyond the annual $5 association dues. The "national board of insurance underwriters. according to Mr. Wightman and other officers of the radio association, has held that the use of aerial wires for radio recep tion Involves some hazards; but still more serious objection has been raised to the connecting of radio receiving sets with high-voltage light and power wires. The com paratively negligible voltage of telephone wires eliminates the pos sibility of objection to the use of the adapter. The adapter itself consists of a condenser, triangular in shape, twoi inches to the side and half an inch in thickness. This is connected up inside the telephone receiving box and with the radio receiving set. Any receiving set may be connected, permitting the present wide range from simple home-made devices to the most costly apparatus.. The adapter or condenser does not im pair or interfere with the ordinary uses of the telephone. , On the con trary. Mr. Wightman maintains that its use will tend to steady telephone circuits against any sway current or unbalanced Induction. The Seattle Radio association has a membership campaign well under way covering the whole Puget sound region. The declared purpose of the association is to establish a broadcasting station of the best and most modern equipment, capable of a wide range of service. The asso ciation officers believe that the telephone ' wires offer an ideal dis tributing system. The first con tract offering use of the adapter was made with the Puget Sound Telephone company of Everett be cause this is an Independent con cern. The adapter and its possibili ties have also been brought to at tention of )ocal representatives of the Bell telephone interests, and en couragement - of its general use .Is under consideration. Mitor Radio Wavea and Ripples: t. Hw mnch weald a regenerative .--tver cost me tf I made the varlo--.eters and the vano-coupter mreelf? 3. ouM 1 hear Waahincton and Call raian aiatioas oa ttls set S Wouid a copper wsra No. 14. TS feet cik and buried atwat S inches In the -iun't make a better around than a atrp;pe7 J sv. Portland, or. 1. Such set. including a storage attery and telephone receivers, will oat you about 135. J This wl!l depend on tha heighth nd kind of an aerial you will uae. he proitmlty of power lines, close rs ef tail steel buildings and local Ltmosrheric conditions. . No- The water pipe Is the very st ground you can find in the ty. Editor Radla Waves aad Kinpies: 1. I wish to make a variometer. What re should the rotor be fir the best re j.ta on short wae re-epton? 2. Can an amateur make a ltrbrninc wlrh that wt-i pas the laaurance re- uire meats f a. X am incloaiag Editor Radio Wavea and Ripples: 1. When I put a phone condenser across my telephone receivers tha sig nal are cut down entirely. What does thia show? S. How many plates ant needed In a variable condenser to get .OOl mfd. capacity? a. Is a alnsle or two-circuit Jack beat for the detector tubs? 4. Will AO turna of wire wound en an oatmeal box do for a single circuit tuning coli? K. W., Uandon. Or. 1. Your condenser must be short ed or It would Increase the loudness of the signals somewhat Instead ot cutting them down. Would advise making or buying another one. 2. A condenser of such capacity usually has 43 piatea In It. . Use the two-circuit Jack be tween the detector and first-stage amplifier. 4. Yes. This will do for receiv ing short wave lengths as Is used In radiophone. Tap about every six or eight turns and'eonnect the taps to a multiple switch. WAVE ANTENNA TO COMBAT STATIC IS NOW BEING USED Receiving Aerial of One Full Wave Length Necessary to New Process, Its Length Is Nine Miles. Editor Radio Wavea and Rlppiea: 1. I have a crystal receiving set which has gone bad and 1 can't receive any more alcnale oa it. Have you any eus seetinns as to how 1 can remedy the troubles ? 2. I am ulng a horlsontal loop around the attic. This loop Is 3d feet long and f"et wide and has Its ends connected. How can I connect this loop up so thai I can set a looser wave lensth out of It? S- W.. Jurt.and. Or. 1. Scrape all the connectiona of the receiver parts and solder thor oughly. The crystal of the set may have lost Its sensitiveness. If that is the case It would be better to get another and fresher piece. 2. It would be better if you leave one end or the loop msconnectea and connect one of the wires to the lead In leaving the other free. Editor Radio Waves and Ripples: 1. I want to put an antenna In an attio 43 feet long and 25 feet from the ground. How many wires ahould 1 need to get coed reeults with a crystal receiving set? What kind of wire should 1 use? INTERESTED BEulXXKH, Portland. Or 1. Run one mire all around the attic and connect one end of it to your lead-in wire, leaving the other end of the loop free. 2. Us either bare or rubbrr-cov- ered copper wire, stze It. If bare e ia used be sure that it la in- 'faulated from the-attic 4y porcelain! V -k - ... - WnnhA THE thousands of amateur radio fana, a majority of whom are realising for the first time what an interference static is to the re ception of the various programmes broadcast, will be. Interested in knowing what means the large commercial companies, such as the Radio Corporation of America, are taking 'to offset thia atmospheric disturbance. Perhaps the chief means used by the radio corporat'on is In the type of aerial. This ia known as the "wave" antenna, which in addition to reducing static interference, has greatly Increased the efficiency ot trans-Atlantic wireless telegraphy. In order to fulfill all of the re quirements of the theory covering the operation ot the new antenna. It Is necessary to have a receiving aerial one full wave length long, or in other words, a receiving aerial wire miles in length. This la exactly what has been installed. The aerial ' Is nine miles long and Is supported on poles 30 feet above the ground, one end being grounded through a noninductlve resistance, and the other through a variable inductance. With this wire the Rlverhead station is daily receiving five different European stations simultaneously without In terf erence. To illustrate the operation of the "wave" antenna, an engineer of the Radio Corporation of America has drawn the following analogy: "If we look upon the new anten na as a' large lake and the wind aa the static, we can get an idea how It works. Now. suppose the wind is blowing across the lake from east to west. At the eastern end there will be little r no ripples, but as we get to the western end the ripples will gradually increase In si me to full waves. If the 'shore at the western end is a gentle slope of sandy gravel, the waves will be dissipated and will not be reflected. "If. on the other hand, the shore of the lake is precipitous and rocky, the waves will be reflected and will disturb the eastern end of the lake. Now this antenna, having a non-inductive resistance at Its non-receiving end. corresponds to a sandy shore, because It absorbs the static and interfering waves and does not reflect them. Carrying the analogy further. If we place a stationary paddle wheel at the western end of the lake, which is revolving uniformly and producing waves of a uniform char acter, these waves will travel stead ily forward toward tha eastern end and will net ba interrupted by or stopped by the wind. This paddle wheel corresponds with the trans mitting station and the wave i sends out is equivalent to the waves from the European station. "The tests which have been con ducted completely confirm " this theory. When the receiving appar atus la placed at the end which is grounded through the non-inductive resistance it is Impossible to hear anything but a terrific roar to con tinuous static discharge. Using the wire-properly as "wive" antenna. trans-Atlantic wireless communica tion can be carried on without any difficulty, despite the static." This antenna system can not be carried out by the amateurs because of lack of space but the system sug gests many promising methods which radio engineers are busy on and hope to solve this problem of remedying if not eliminating static in the radiophone broadcast enter talnment. Careless Operation May Distort Signals. Characteristics mt Vaeauna Tabes A law May lie Chh. D' ISTORTION of signals in ampli fier circuits is due to the char acteristics of the vacuum tubes treed and careless operation, according to experts connected with one of the lsrgest vacuum tube distributing concerns in the country. The output of amplified current may be distorted by any one of the following four conditions, declare the vacuum tube men: 1. If the normal grid voltage is positive a current will flow from .he filament to the grid and this will reduce the maximum value of the voltage of the positive half cycle Of the incoming oscillation, resulting in distortion of both input and output currents. 2. If the Incoming signal volt ages are excessive, the plate cur rent will not oscillate within the straight Una part of the character istic 3. If the input voltage Is not applied to tha straight line portion of the plate current grid voltage characteristic. 4. If the transformers and asso ciated apparatus are improperly designed distortion will result. Freedom from distortion requires a tube having a substantial straight line plate current-grid voltage char acteristic at negative grid voltages. An amplifier cannot be operated at a normal grid voltage of 0 without distortion, but must be operated at some negative value of grid voltage so that this value, plus the maxi mum positive voltage of the incom ing signal will not produce a posi tive voltage on the grid. The results from the operation of a vacuum tube depend largely' on the operating position on Jhe plate current-grid voltage characteristic curve as determined by the normal grid voltage. This value can be fixed by the use of a C battery with potentiameter between the grid and filament. These facts are presented with the thought that many experimenters will find it interesting to conduct experiments with vacuum tubes as detectors and amplifiers using a C battery. Some ofthe results obtainable will prove very surprising. The vacuum tube can be operated as a detector with out grid condenser or grid leak by using a C battery to locate the operating point at the point of maximum curvature on the plate current-grid voltage characteristic, a a a The use of radio for the transac tion of governmental business has been demonstrated successfully by the postpffice department. Post master General Work announced to day that hereafter radio will be used exclusively as the means of communication among branches of the department. Great saving, he said., will be made by abandoning the telegraph and the work will be greatly expedited by dependency upon radio. The cost of radio messages a word, postal officials assert, is less than one-eighth of a cent. Wash ington station transmitting admin istrative orders, requisitions for supplies, reports from field inspec tors and communications for the air mall service is averaging 1000 mes sages a month. se Bakelite and formica, are the best materials for panels, but they are expensive, and when it' comes to cutting holes for meters, a difficult Job presents Itself. A smooth, straight-grained board will make a neat panel. The main objection to wood is that Its grain mars the panel's appear ance. As it Is not a perfect insulator. ARRANGEMENTS have been practically completed for the erection of a broadcasting station in New Tork city which is to represent the most advanced state of the art of radio both technically and in the entertainment sense. The station will have a range of 1500 miles, ap proximately, and all of the latest improvements In radio-telephony en gineering will be incorporated. Tlie Radio Corporation of America will build this super-station, utilizing the experience culled from the operation of the Newark station, WIZ. of which it is part owner, and which will close with the opening of the new station. On the roof of Aeolian hall, in the heart of New York city, which is to be the site of the new station, two 100-foot towers " with a 200-foot aerial will be suspended 380 feet above the earth. Several special de vices for transmitting both solo and ensemble music with exceptional fi delity will be installed The station will transmit simulta neously on two wave length from the same aerial but from separate studios. The two factions observed in the majority of radio audience will in this manner be served. Two distinct programmes will be avail able every evening, one classical and one popular. Both programmes will be handled separately in the two studios but modulation will be gov erned from a central control room. The station will be equipped with four powerful transmitters, two for regular operation and the other two for replacement in emergencies. . ' The aerial and the ground connec tions possess what is known as dis tributed inductance and distributed capacity, whereas coils and condens ers possess concentrated inductance snd concentrated capacity, respec tively. The concentrated- values hold their energy within themselves, but the distributed values radiate and absorb energy from the outside, -so in order to get the maximum ab sorption the antenna system should consist, to a large extent, of the distributed values. This means that it is best to use very little concen trated Inductance and concentrated rapacity in this open circuit. With short waves thia is especially desir able, but with long waves it is not always practical, and with these waves a loading Inductance of quite a high value will do little toward lowering the efficiency. But as the short waves are the ones that most interest the broadcast listeners, this theory holds true. . For best results on the snorter waves the aerial snouia nave a wave - length of approximately three-quarters of that of the wave ength that it is desired to receive. On this basis an aerial for 360 meter reception should be about 180 feet long, but aerials from 100 feet to about 200 feet will do. If your aerial is longer ithan this you will not be able to use enough turns in your coil to convey t noagh energy into , your detector circuit. When a longer wave, such fis 1453 meters, is wanted, it is bet ter to add a coil of iitductance than to enlarge your aerial, as the in- .A. .1 . i rr n 1 elrDnnth WHIlM Tint be commensurate with the extra I trouble. LJL - -Ife 5r Hook-up of the new Armstrong snper-regenerattve system, employing a single vncuuni tube only. The constants of thes circuit are aa follows i 1 Primary of -vario-coupler. 12 Secondary of varlo coupler with twice the usual nmonnt of tarns. 3 Variable condenser, .OOl mfd. capacity. 4 The C battery of fonr volts. 5 Variable condenser, .0005 mfd. capacity. Duo-lateral coll 1250 turns. 7 Duo-lateral coll 150 turns. 8 Variable condenser, .0005 mfd. capacity. JPlxod condenser, .0005 mfd. capacity. 10 Resistances, 13,000 ohm each. 11 Vartnble condenser, .001 mfd. capacity. 12 Iron choke coll. 100 mil henries inductance. Loop aerial, 12 turns on a three-foot square frame. B-battery used of SO volts. SEVERAL hookups of the new Armstrong super - regenerative receiver, with which amplifica tions of 100,000 can be obtained, al ready have been given out to the radio amateurs of the country. In these hookups two vacuum tube were used to get the super-regen erative action. Practically the same action can be obtained with one tube -only, ac cording to Armstrong, the inventor. The one-tube circuit requires very careful handling by the experi menter, who will hae to learn the delicate adjustments by experience. It is quite likely that the proper re sults will not be obtained until after a great deal of experimenting on the part of the amateur. a e The two large duo-lateral coils must be In inductive relationship with each other. It will be found that this relationship is very crit must be exercised in the adjustment ical and the greatest possible care as well as obtaining the correct amount of capacity in the two con densers S and 8. . a e e In the one-tube receiver the -super-regeneration is accomplished by the simultaneous variation of the posi tive and negative resistances of the circuit. This is achieved by a sec ond feed-back circuit, shown in the i accompanying diagram under the numbers 5, 6, 7 and 8, which ia a-d-justed to oscillate at a lower fre quency than the incoming signal. The proper relations between the positive and negative resistances are obtained by adjustment of the condensers S &nd 8 and the coupling between the colls 6 and 7. a The grid battery as shown in the diagram consists of two pocket flashlight cells connected in series, giving a total of about four volts. The negative terminal of this tiny battery must be connected, to the grid. The 12.000-ohm resistances and .the 100-mill-henry iron choke coil are standard instruments used for filter purposes in telephone re peater circuits and can i be obtained from stores handling telephone sup plies. s - e a It must be remembered that there are seven critical adjustments to be made in. such a receiver. This fact is not stated to discourage the experimenter, but to impress upon him the importance of very delicate and careful adjustment. It also will serve to remind him that in tht event of failure at the first or sec ond time not to give up in despair but try again and again until com plete mastery of the adjustabl parts of the circuit is obtained. The subsequent results will amply re pay him for his trouble. Loudness of Signals Due to Amplifier Voltage. Careful Experimentation Only Will Bring Good Results. ' Efforts to produce radio-controlled tanks appear to be the very latest step , in government radio work lor the army and probably for the marine corps material. To date no definite plan has been evolved by radio engineering experts, but after the navy successfully operat ed the Iowa by radio control the leading scientists of the army be lieve radio-controlled tanks are a certainty. Today one out of every eight or ten army tanks has a radio trans mitting and receiving set. enabling this leading or control tank to keep in close touch with headquarters constantly and communicate by sig rals with its fellows in battle. Such efficient liaison would be a tremen dous step in military science, as the tanks could also serve as message centers for the infantry troops as well as spot artillery fire, and keep headquarters posted as to "the po sition of the advance lines. Before the year is out it is believed that all army tanks will be equipped with radio communicating outfits and that the marine corps will also have tanks equipped with radio. At the recent maneuvers at Gettysburg the marines used some army tanks, one of which was a "master tank" equipped with radio. s e a Yosemite's' granite cliffs rise straight Into the air for 3400. .4000 and occasionally 5000 feet. Yosemite valley is literally a "hole In the ground," and some wireless experts riciaeeri local conditions' were en tirely against successful operation of a wireless station mere, never theless, valley folk recently have been getting news reports, weather predictions, market quotations and lots of good music right out of tht air. with no other aerial than wires strung between two of the giant trees with which the valley floor is forested. Edwin J., Symmes of Alameda, Cal., put in the first wireless set for his own amusement and has received messages from several core damped and Undamped wave stations, in cluding Honolulu and Catalina is land. . Government authorities also have put in a station, which will be used to keep in touch with the out side world. A WORD to the amateur on am plifers: . Using, a two or three-stage am plifier, it must be remembered that the loudness of the signals depends upon the voltage used in the plate circuit of the iast. stage. This voltage depends upon the type of tube used. Some tubes will stand from 150 to 200 volts on the plate circuit before they will operate at a maximum when used as amplifiers. The exact voltage in this regard wil! have to be deter mined by careful experimentation. When adding a second, and more often a third stage of amplification, there is sometimes considerable whistling or howling, together with a rasping, scraping noise. This is sometimes due tov corroded contacts on the bottom of the lamps a con dition that can be corrected with a little sandpaper. Sometimes this noise may be eliminated by using a separate "B" battery on the last stage of am plification, connecting the preced ing amplifiers and the detector to a common "B" battery. A condenser of large capacity one to two micro farads placed in shunt on the last "B" battery will sometimes help in this regard. Another wrinkle is to ground one terminal' of the "A" battery or use this idea in conjunction with the others mentioned previously. One or all of these precautions will usually cut out the unnecessary noise in amplifier work, although it must be remembered that any am plification of signals also picks up and magnifies the atmospheric and ether disturbances in a like degree and that much of the disturbance at audio frequency at least, will have to be endured. The generally accepted theory of the cause of "fading" is the Ioniza tion of the ether, due to saturation by the sun's rays. For this reason reception invariably is much better at night than in the daytime. "Fad ing" at night time is thought to be due to strained conditions in the ether, which momentarily permit signals to travel further in certain directions than normal. Perhaps the best way to explain this is by the analogy of winds, where, due to conditions in the atmosphere, we suddenly get a terrific rushing wind blowing in one direction for a cer tain distance, the velocity of the wind varying according to the con-i dition. Something similar to this' probably exists in the ether, making reception good at one moment and weak at another. This condition, of course, does not affect stations within close normalrange. The Store J. E. Weed, Mgr. The Oldest Exclusive Radio Store in Portland. Z. USE ANTENELLA AND NO AERIAL ". Before purchasing a Radio set consult an established radio store where you get the benefit of years of experience and service afterward. We carry all the leading makes of sets and parts for making them. SEIBT PHONES FOR LOUD SPEAKERS. Mail Orders Filled Promptly. Write or Call for Catalogue. 310 Oak Street Portland, Oregon Do Your RADIO Shopping With Us Complete Sets and all "THE MAKIN'S" jiiiiiimiimiiiiiiiiiimii!iimiiuiiiii ervice We give the very best of service FREE to every one who buys their radio set from us. You are then protected by buying from us. See our new one -control, three -stage receiving set which has automatic battery con trols and can be tuned in less than a minute. t Radio Service Bureau GASCO BLDG. MAIN 4538. miiiiiiiiimmiiiiiiiiiiiiiiiimiiinii ELECTRIC CO Operating KQY 75 Sixth St., Portland Radio Sets of all kinds, made to your order. Complete sets in stock. Large supply of parts. SMITH-McCOY ELECTRIC CO. 64 Alder St. Main 8011. HIGH-GRADE RADIO SETS COMPLETE LIXE OK P.IKTS M. J. Walsh ELECTRIC CO. 106 Fourth Street PORTLAND, OR. J SURE WE HAVE Sockets for the PEANUT TUBE TUBE $8.00 SOCKET $1.00 Use a Standard Rheostat ONE DRY CELL. HALLOCK & WATSON 192 Park St., Portland, Or "KGG" The Journal's Broadcasters. E. L. 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