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1. A great deal of talent is lost in the world for want of a little courage Every day sends to their graves obscure men whom timidity prevented from making a first effort who if they could have been induced to begin would in all prob ability have gone great lengths in the career of fame The fact is that to do anything in the world worth doing we must not stand back shivering and think ing of the cold and danger but jump in and scramble through as well as we can Sydney Smith Bad will be the day for every man when he becomes absolutely contented with the life that he is living with the thoughts that he is thinking with the deeds that he is doing when there is not forever beating at the doors of his soul some great desire to do something larger Phillips Brooks Reading is to the mind what exercise is to the body As by the one health is preserved strengthened and invigorated by the other virtue which is the health of the mind is kept alive cherished and confirmed Addison Success or failure in business is caused more by mental attitude even than by mental capacities Walter Dill Scott When you get into a tight place and everything goes against you till it seems as though you could not hold on a minute longer never give up then for that is just the place and time that the tide will turn Harriet Beecher Stowe www americanradiohistorv com June 1930 NATIONAL RADIO NEWS 15
2. Another well known development that Radio in the Movies WWW americanradiohistorv com RADIO owes its rise to radio research is the talking motion picture It is a fact readily admitted by talkie experts that the success of the talking moving pic ture is due primarily to the perfection of the electrical reproduction of sound which was accomplished in the radio broadcasting transmitter and receiver Without this perfection neither the de sired volume and tone quality nor the delicacy of control necessary for the synchronization of sound and sight would have been possible No phase of research has been more fertile in the production of radio by products than that which has centered about vacuum tubes In the last decade thanks to radio the use of vacuum has invaded practically every field of in dustry Through its application par ticularly in the form of vacuum tubes our senses of sight touch and hearing have been enormously extended One of the amazing tubes is the West inghouse grid glow tube the most sensi tive power controlling device the world has ever known If only the amount of energy expended by a fly crawling one inch up a wall is applied to it the tube can actuate a relay powerful enough to start almost any electrical operation Then there is the photo electric cell better known as the electric eye This device is sensitive to light and shadow Any change in the intensity of the light
3. IT DOES NOT MEAN THAT WHILE STICKING 1 To TRE JOB AT HAND q WE CANNOT PREPARE FOR THE JOB WE WANT X ON THE CONTRARY Ha THAT IS THE VERY ba THING WE SHOULD Do ABRAHAM LINCOLN SHOWED US N How N R I AT R M A SHOW N R I will be represented at the 1930 Radio Manufacturers Association Show at Atlantic City June 2 6 by Mr Joseph Kaufman Chief of the Consulting De partment Mr Kaufman will make a thorough study of Radio problems for the coming season as well as of the new equipment offered by Radio manufacturers A forthcoming issue of the News will carry a complete account of his findings at the R M A Show Watch for this article it will contain important data for every Radio man N R I SERVICE MANUAL Continued from Page 10 to determine the efficiency of condensers The apparatus consists merely of an at tachment cord 110 volt 25 watt lamp and socket and two test leads Connect as follows 1 One conductor of attachment cord to lamp socket 2 One conductor of attachment cord to one test lead 3 Other test lead to other terminal of lamp socket Plug the attachment cord into a 110 volt outlet and insert the bulb into the lamp socket a When the two test leads are touched together the lamp will burn at full bril lianey b When the two leads are touched to the terminals of a large condenser such as 2 Microfarads the bulb will glow its brilliance dependent on the siz
4. Fig 4 This shows the location of the remote control set and flexible shaft control is a flexible shaft such as those used in dental drilling machinery and speedometers In other words a modified remote tuning control Volume control of the re ceiver together with the means for switching it on and off require only that the actual units necessary for these op erations namely the vol ume control variable re sistance and battery switch be connected with the circuit of the re ceiver by means of extra long shielded leads Usually it is found most convenient to locate the tuning controls directly on the dash or at the driver s left on the side wall of the car See Figs 7 and 8 From either of these loca tions the flexible shaft and leads go directly to the set The actual placing of the receiver depends largely WWW americanradiohistorv com June 1930 NATIONAL RADIO NEWS 13 Auto Radio upon the size and type of car in which it is to be installed for instance in a coupe or roadster the logical place for the set and batteries would be in the compartment occupied by the rumble seat Fig In a sedan or touring car having an unusually long hood ample space for locating the receiver will be found directly forward of the dash under the In others space may be found under the 7 hood floor boards Fig 4 or even under the seat another place for the set is on the running board wh
5. Fig 5 a ab OPRER AGR Second five or ou TE corina urns of wire may PANEL strung around the inside of the car at the top where they will be out of the WIRE way If this latter A system Fig 6 is i 3 used the collector WITH REMOTE CONTROL j SPARK may be connected to SIDEWALL AND CABLE 2 7 the receiver as a DI ED Di BEHIND straight antenna or as a tuned horizontal loop When used as a loop some experi mentation will be OWN THE UPHOLSTERY For elimi of the resistors WWW americanradiohistorv com 14 NATIONAL RADIO NEWS June 1930 required to determine the correct number of turns to be employed so that the an tenna stage tunes in step with the other radio frequency stages The main source of noise in a receiver installed in a car is from the spark plugs induction coil and associated igni tion wiring To prevent pick up from the wiring it has been found necessary not only to shield the receiver itself but also to run the receiver battery wires and all other leads connected to the set through flexible metallic braid grounding the latter to the car s frame Fig 3 Eliminating the noise caused by the discharge of the spark plugs presents a CONDENSER F RECEIVER WORM ON ENO OF FLEXIBLE SHAFT GEAR ON CONDENSER SHAFT GEAR ON DIAL SHAFT Ss GEARS ON FLEXIBLE a rfi SHAFT eii t Fig 9 Some methods for gearing the tuning con trol to the condenser shaf
6. along after Radio work He found plenty of it Set owners wanted their receivers kept in good shape Others needed accessories which he sold at a profit On top of this he secured orders to build receivers for three of his friends To make a long story short he earned several hundred dol lars profit from June to September simply because he went after business instead of waiting for it to come to him Today he owns a Paying Radio business built up during the season generally thought poor for Radio His fellow student on the other hand neglected his opportunities Just as Brietbart neglected his scratch Breitbart lost his life the student four important months and the business built up by the other fellow who studied and worked E R HAAS Vice President amp Director Gets African Ticket EWS received this month from Keetman shoop South West Africa shows again that N R I men are making good all over the world Student E G Thompson telegraph operator for the South African Railways and Harbor Commission just passed the stiff examina tion held by the West African Postmaster Gen eral Of the forty two candidates Mr Thompson was the only one to ob tain the first class license The only other successful candidate received a second class ticket Mr Thompson s high grades spell pro motion with his present employer as he was promised a more responsible posi tion subject to passing the Postmaster Gener
7. and tight The rotor of the second radio frequency stage is grounded through a pig tail to the ground lug of coil L2 sec ond radio frequency stage Make sure that this wire is intact Make sure also that the other two condenser rotors are grounded to the condenser frame through pig tails 6 Poor Coil Grounds The secondary winding of each coil is grounded through one of the coil fastening lugs This con nection must be clean and tight 7 Other Grounds Check all other ground connections such as by pass con denser grounds volume control ground and connection at Ground terminal post 8 Defective Center Tap Resistor Os cillation may result if center tap resistor R10 is open or not grounded Use the continuity test to check this unit 9 Open By Pass Condensers One or more open by pass condensers in the re ceiver may cause oscillation This con dition is best checked by using the Con denser Test An open condenser is however a somewhat rare occurrence 10 Grid Resistors If the resistance value of the grid resistors R4 R5 is too low oscillation may result Check these units for proper resistance by means of the Ohm meter 11 B voltage tco high Check the WWW americanradiohistorv com NATIONAL R DIO NEWS June 1930 B voltage in the radio frequency and detector stages If too high refer to the Trouble Chart 12 Screen Voltage Too High Too high a screen voltage c
8. set batteries and tuning control nating spark plug interference note the use cable presents another problem which cannot always be solved by directly connecting the end of the cable to the condenser shaft through a coupling medium such as a universal joint Fine tuning or in other words the direct turning of the condenser shaft with out back lash which is just as necessary whether the set be in a car or in the home is very difficult while the car is in motion Some means of gearing down the revolution of the tuning control knob for vernier action must be utilized Straight and worm gears have been found reliable and satisfactory for this job Moreover their use permits locating the set so that there are a minimum of twists and turns in the flexible cable itself Details of the gear drive are shown in Fig 9 To a certain degree the amount of signal coming from the loud speaker is dependent on and in propor tion to the efficiency of the antenna In automobiles where size injects a limiting factor the pick up is boosted by the use of several stages of high gain radio frequency amplification but of course there is a limit be vond which they cannot be used effectively Several ways of providing an accept PR able collector are possible First one may use a copper screen fastened to but in sulated from the roof inside 3 TO 10 TURNS PURE WRULATED Fis 6 How to mount the coil antenna in the roof the car
9. 6 000 And to each one of them has been mailed a membership card and a letter of wel come Right here I want to tell you what the Alumni Association has done so far and what its ambitions are for the future With Association dues received from applications we opened and equipped a small office in the U S Savings Bank Building 14th and U Streets Letter heads envelopes membership cards and copies of the constitution were printed to send to prospective members of the As sociation The balance of the funds have been deposited in the U S Savings Bank Now as to the future We have hopes of a publication devoted entirely to the Alumni Association carrying news of N R I graduates This is going to be a big job and will take plenty of coopera tion Help has been promised along this line from the Editor of the N R I News who has proved a real friend to the As sociation We are going to work with Mr Murray N R I Employment Man ager to assist him to place graduates in good paying jobs In the future we may even open up an Information Service for members to provide data from the U S Patent Office Official Radio Publications from the Bureau of Standards Depart ment of Commerce etc Now fellows the Alumni of a great school like N R I should have a Creed We have one and a good one too It is taken from the Constitu tion of the Association I want every man to read it over several times so that he will kn
10. Ana Clancy has the distinction of being the world s first Radio Television girl by looking im em the first Television broadcast in history She is not only hearing the voice of WendelisMcMahill but also seeing his Tele visioned features as he speaks www americanradiohistorv com TE
11. hundred off shoots in cluding perfume and soda water tobacco seasoning and billiard balls fertilizer and motor fuel Thus the story runs through the entire history of scientific development Thus also the story runs through the various acts of the gripping radio drama When Dr Frank Conrad began tinker ing with wireless it was with the sole hope that he might find a way to send sound over a distance without wires He and other engineers worked long and hard and they reached their goal But their achievements did not stop with success in radio broadcasting for every discovery leads to a further discovery Other scientists investigated The re sult is that while the broadcasting art has been and continues to be the major outcome of investigative effort in the radio field there has issued in addition a great host of valuable by products of radio some of which give promise of one day transcending in importance the mother invention Scores of these by products have at tained mature development and are now in actual use Others are incubating in research laboratories awaiting further development with their eventual prac ticality not for a moment doubted Still Kadio Traffic Control System Radio s amazing growth has created a number of new fields by products which require men with specialized Radio training fields of opportunity that guarantee that the tech nically trained man will always be in d
12. this condition exists is to substitute other tubes in the radio fre quency and detector stages wie i 3 Lack of shielding The shielding is applied to the receiver principally to pre vent oscillation and it is therefore quite obvious that all shielding must be in place and properly secured to obtain cor rect operation of the receiver Make sure that the variometer shield coil shields tube shield condenser gang shield and the three small shields under the condenser gang are in place Each shield must be firmly fastened by its screws or clips and good contact ob tained between the shields and chassis frame 4 Variometer Grounded The vario meter is grounded only through a special ground wire running to the ground ter minal of the condenser C8 and insula tion is provided between the variometer bracket and the condenser gang so that there is no path to ground from the vario meter direct to the condenser gang Oscil lation is liable to result if these two units become grounded together through a poorly insulated bracket Check this condition by disconnecting the variometer ground lead and checking between the condenser gang and variometer bracket with the continuity test No reading in dicates a properly insulated bracket 5 Poor Condenser Gang Ground The condenser gang is grounded to the chassis through the bracket support at one end and the single stud at the other Make sure that these two joints are clean
13. 6th and U Streets N W Washington D J E SMITH Publisher E R HAAS Editor Copyright 1930 NATIONAL RADIO INSTITUTE Washington D C June 1930 REITBART Ger many s professional strong man could drive iron spikes through two inch planks with his bare fist Yet for all his strength a mere scratch of the skin caused his death Carelessness or supreme belief in his physical superiority made Breitbart feel im Possibly many E R HAAS mune to ordinary ills engagements kept him too busy to care for himself He considered that scratch unimportant neglected it and his life was the price f Many seemingly unimportant things are vital Had Breitbart realized the consequences of delaying medical atten tion he would have been alive today This story reminds me of the fellows who neglect little things and as a result lose out The case of two N R I students out in a little Kansas town last Summer is an example of this Both of these fel lows had completed the same number of lessons One man felt it useless to de vote hours to study during the hot weather didn t feel he could get Radio business anyway in the Summer So his spare time was spent trying to keep cool resting swimming fishing The other fellow knew business was there if he went after it He made up his mind to grasp the opportunities missed by Radio men who laid down on the job While these fellows loafed he plugged
14. A receiving set isn t worth much unless there is something good coming over the air When your customer buys a set he does so on the faith of bringing in good and enter taining matter with it In the past 10 years the art of broadcasting and program building has rapidly advanced along with the technical side of the Radio industry An army of artists announcers and program directors create the wealth of broadcast material always on tap for the set owner awaiting to be released at the twist of the dial The President of the United States speaks the landing of the Graf Zeppelin is described sports are broadcast orchestras jazzticulate the world s best show is on the air every night The public favor has been captured by all this in fact its interest and desire to listen in has caused it to expend hundreds of millions of dollars for over 14 000 000 Radio sets and millions more in keeping them serviced and repaired If you have not already done so it will pay you to familiarize yourself with some of the favorites of the air some of the outstanding regular programs Such knowledge will prove helpful in giving demon strations and closing sales Good demonstrators in variably make it a point to know the types of pro grams on at a certain time of the day and evening and tune in the best for their prospective buyers So make the most out of the programs on the air Have some idea of what your customer wants to hear and what yo
15. FROM N R I TRAINING HEADQUARTERS 2 VOL 2 NO 11 WASHINGTON D C JUNE 1930 Station L I O N Broadcasting See Page 3 LD MAN SUMMER SLUMP is on his death bed Nine years ago he was hale and hearty last year his strength began to fail Today he is on his last legs not expected to live through the month Modern receiver construction improved summer reception dealing him a severe body blow All Star summer programs are the last straw He is out for good In his place is Year Round Business offering good profits regard less of season The country is Radio minded and set owners demand as much from receivers in July as in January Radio Tricians who go after the work will find a busy summer ahead HEN the newspapers carried the news that Babe Ruth had signed with the Yankees for 80 000 a year many fans felt he was lucky to get so much for playing baseball a few hours each day They see Ruth on the diamond but they don t see him away from the ball grounds or after the season is over They don t know that he trains from early morning until night day in and day out in season and out Stiff work outs in the gymnasium long jogs on dusty roads endless training Pleasures the ordinary fellow enjoys are not for Ruth No late hours no tobacco few sweets Ruth worked hard for his 80 000 con tract Last Fall and Winter while the Bill Joneses of the semi pros were loafing th
16. al s Proficiency Examination Congratulations student Thompson You together with dozens of other N R I men are carrying the good work of N R I into the far corners of the world We are proud of what you have accom plished and wish you continued success in Radio Electrad Incorporated 173 75 Varick Street New York City have prepared in teresting literature on the Electrad Lof tin White Amplifier N R E men are invited to write them for this pamphlet BOSCO ON AIR Station KVEP Portland Oregon an nouncing our next feature the N R I Hawaiian Trio under the direction of John Dal Bosco Student Bosco and his N R I Hawai ians are a popular feature in West coast programs Tune in some night about 8 00 P M and hear these artists Besides making a record as a student Mr Bosco is making good over the Mike The News wishes him continued success both with his course and with his trio of Radio entertainers Don t miss the July issue of the NEWS If you have changed your address let us know at once so that you can be sure to get your copy www americanradiohistorv com June 1930 NATIONAL RADIO NEWS N R I SERVICE MANUAL N Bosch Radio Receivers Models 48 and 49 This receiver is of the tuned Radio fre quency type using the transformer method of coupling the Radio frequency tubes It uses three 24 one 27 and two 45 type tubes A schematic wir ing d
17. aused by wrong con nections or a defective resistor R11 may be the cause of oscillation Check screen voltages and if too high refer to trouble chart Alignment Condensers The alignment condensers are indi cated at C4 C5 and C6 on the schematic wiring diagram The function of these condensers is to act as vernier con densers across the main tuning con densers C1 C2 and C3 and thus bring the tuned circuits into exact resonance The capacity of the alignment condensers may be varied by means of a bakelite wrench inserted from the rear of the re IRES ANT i Re TABLE OF CORRECT SOCKET VC A Volts B Volts 8 Type Position of Tube of Tube 60 25 60 25 Cycle Cycle Cycle Cycle ic BY 224 Ist R F 24 24 175 150 BY 224 2ndR F 2 4 2 4 175 150 BY 224 3rdR F 2 4 2 4 115 150 BY 227 Detector 24 2 4 290 250 BX 245 Audio 2 4 2 4 250 200 E BX 245 Audio 2 4 2 4 250 200 BX 280 Rectifier MBO Sale es eat i Line Voltage 115 Plate voltages measured Grid voltages measured Screen Grid voitages me Volume control in full on position for all voltages of meter used and may vary considerably from the Readings may also be taken at the chassis pov given below Detector plate voltage read between connectors R F plate voltage read between connectors___ Screen grid voltage read between connectors BY 224 and BY 227 filament voltage read between gt 2 i i i 4 GNO a A t j
18. barely audible 6 Adjust the three alignment con densers in any order for maximum vol ume using a bakelite wrench inserted through the tube shields 7 Again adjust the Selector and Clarifier for maximum Volume 8 Again check the adjustment of alignment condensers for exact setting Condenser Test As mentioned elsewhere in the manual there is a simple test which can be used Continued on page 15 Fig 2 Wiring diagram of Power Pack www americanradiohistorv com June 1930 NATIONAL RADIO NEWS 11 An Open Letter To The Alumni Association I have often remarked to the staff of N R I what a fine bunch of fellows at tended the convention in Washington last fall Every man whether old young or middle aged had that expectant look in his eye which meant he was contented They were satisfied because they were all successful Radio men It was not hard to fathom the real cause of happi ness the N R I Fellows we have gained our knowledge from N R I as well as the pleasure of knowing such men as J E Smith E R Haas Phil Murray J A Dowie I could go right on down the line naming each individual but after naming them all they would still just sum up to one great organization the N R I For fifteen years N R I has been turning out men turning out but not forgetting because N R I has always thought of us That s why the Alumni Association is striving to keep th
19. carefully compiled and is offered as an aid to those enthusiastic pioneering souls who are now finding an outlet for their energies in this newest of ventures in radio Assuming that the re ceiver has been built the first item for con sideration in the car it self is how and where the tuning controls are to be located Naturally it is out of the question to consider that the tun ing dial volume control and on off switch will be mounted directly on the receiver chassis The bulkiness and the lack of a suitable place to locate a receiver So as to be reasonably convenient for tuning precludes this possibility in most cases Therefore we will assume that the tuning controls will have to be placed in one lo cation naturally the most accessible and convenient one while the set itself is located elsewhere in the car Belt drive of the con denser shaft is a possibility but the simplest method of eee erre PI CORNER OF RECEIVER CASE Proofing the set n CLAMP GROUNDS METAL RECEIVER CASE LCADS 7 BATTERY CABLE ENCLOSED MTO Aa Fig 3 Use a clamp to ground the cable shield to the set s case Fig 2 Another method of shock busy and go after this work Editor FLEXIBLE REMOTE CABLE CONTROL DIAL pena LRA gt re j E 230 TI A 3 a END vena ae e he ga N vs a di GAZA m matt saan RECEIVER SLUNG os UNDER FLOOR BOAROS Sunes
20. e Babe was sweating in a gymnasium In the Spring while the Joneses were waiting for the Bush Leagues to open Ruth was out on the diamond plugging away at batting prac tice Year round training kept Ruth s body in perfect shape When the 1930 season opened he was ready for base ball s biggest job A Winter s loafing for Bill Jones means surplus fat he PRESIDENTS PAGE was lucky to get a 30 a week job on a team out in the sticks Ruth s constant training is the secret of his success Bill Jones after season lay off explains why he is a Bush Leaguer The same holds true in Radio The men who stick to their lessons dur ing the warm months when others are loafing are the men who will be the Babe Ruths in this industry The Bill Joneses who lay their lessons aside to gather dust are condemning them ae to the Bush Leagues of Low Pay jobs I am glad that N R I men stay in the big league class The sincere enthu siastic manner in which you tackle your lessons regardless of season clearly shows why N R I Graduates succeed in Radio As Big Leaguers nothing in terferes from the time an N R I man enrolls until he is through the course and in a good Radio job HIS Summer many Radio Tricians are turning their eyes toward four big Radio fields which offer unusual oppor tunities for extra earnings More Public Address installations are in demand tha
21. e of the condenser e On a small condenser 002 micro farads the lamp will not glow at all d The bulb will burn at full brillianey if the condenser is shorted This test applies 110 volts to the con denser and will detect condensers which might break down in use but would not be detected by an ordinary continuity test using a 41 4 volt C battery Bushels of Letters Show N R I Men Cashing In Are a Few I made 150 00 seliing and repairing receivers since I mailed the last lesson I promised to cut out some of my servicing and get more lessons but I saw a chance to make some money and just couldn t pass it up I have made the cost of my course several times over I did so much Radio work in spare time I could not find time to get my lessons in fast enough Carl D Ma cum 611 Spruce Ave Kansas City Mo Here I am praising the course every day for all it has done for me I threw my money back agree ment in the fire the second week after I started S E Bost 112 48th St Wylam Alabama I have worked at Servicing for about seven months and during that time I earned about 2 200 00 John Wippick 121 Fern St Darby Penna I wouldn t take ten times the cost of the whole course for what I have already learned about Radio It is worth the cost just to be associated with such a bunch of good fellows I turn down work every day because I feel like it is more im Portant to keep up wit
22. e old bunch of graduates together We re hav ing splendid success and the cooperation of hundreds of N R I men Here is a letter I received with an application just the other day I would like to offer my congratula tions and thanks to those public spirited men who formulated the Alumni It is one of the grandest things I know of to keep members of such an institution as the National Radio Institute in close touch and harmony with one another During the Great War battalions of men fought shoulder to shoulder Those who were left are today holding reunions to get together and renew old acquaintances and experiences Today we graduates of old N R I are out fighting the battles of life Indiscriminately we are scat tered over the face of North America and throughout foreign countries but we can fight those battles in mass forma tion through such an association as the Alumni Therefore I say again con gratulations and thanks to those men who made for the rest of us such a pos sibility I am cordially yours George F Doan What a letter Such fellows as Doan belonging to any organization are bound to make it a success There are more than 6 000 graduates men who have gone through the same routine of study the same as you and I We want every one of that number back again We want to know each and every one of them and we want them to know us I have already received 500 applications for membership out of that
23. emand Fortunate s the Radio man no ruts or blind alley jobs to stare him in the face J E S It s these broad new others exist only as vague ideas in the minds of their sponsors but it may be that these ideas are the forerun ners of some of the great est inventions of all time A thrilling by product or outgrowth of radio is tele vision Steady progress is being made Closely allied to televi sion is another form of sight transmission known as ra dio photo The owner of a ra dio photo re ceiving set re ceives actual facsimile prints of the subject matter that is being sent A style scout in Paris can sketch a Worth creation hand it to the operator of a radio photo transmit ter and immediately her store in Chicago begins receiving an exact photograph of her drawing Again a London banker can write a check for 20 000 pounds place it in a facsimile transmitter and a negotiable duplicate reaches the hands of a New York broker in a few minutes Facsimile transmission by wire is not new but the use of radio for this pur pose is a recent development Probably the best machine for performing this feat is the one developed by Dr Vladi mir Zworykin A picture drawing or piece of written or printed matter four inches by five inches in size can be placed on a transmitter be sent through the air any distance within the broadcast range be picked up and reproduced com pletely in four minutes time
24. ere it may be placed in a metal box strong enougn WIND HOOD SHIELD FLEXIBLE CABLI Receiver RECEIVER estrias g gt e lt A m A A a 11 DASH x si A SUPPORTING FRAME 3 Still rig gs Mounting the set under the dash provides a short tuning con trol cable to the dash board to serve as a step if necessary COPPER SCREEN ANTENA LOCATED in TOP OF C ANTENNA LEAD AFTER PASS Ar ING THROUGH DASH 1S RUN THROUGH A SHIELDED FLE XIBLE TUBE WHICH tS GROUNDED i RECEIVER a RECEIVER SET 15 GROUNDED TO METAL gt CASE WHICH IN TURN lt 1 GROUNDED TO p CAR FRAME CAR FRAME Fiz 5 Details of the antenna ground system for an auto radio installation To take up the excessive vi bration which will be visited upon the receiver chassis while the car is in motion both to prevent breakage of the tubes and to minimize microphonic noises produced by vibration several systems may be employed One is to support the receiver chassis in a frame by suspending it at the four corners of each end by means of springs This method is illustrated in Fig 2 Another is to make a sling of sev eral layers of rub ber strips and sup port the receiver chassis from hangers as shown in Fig 1 Discarded inner tubes are excellent for this purpose Turning the con denser shaft by means of the flexible A AND B BATTERIES Fig 7 Showing the installation details for the
25. falling on the eye causes a corresponding change in the amount of cur rent passing through the unit Possible applications of the electric eye are lim ited only by the bounds of Dr Frank Conrad s Television Transmitter the imagination Were one to list all of the uses to which it might conceivably be put the total number would reach well into the hundreds Already the eye is used in Pittsburgh and Wilkinsburg Pa to control traffic automatically by operating traffic signals when it sees approaching Radio Facsimile Transmitter By RALPH C EDGAR Editor Westinghouse Magazine automobiles It serves as a never wink ing watchman ready to operate an auto matic fire extinguisher when it detects the faintest wisp of smoke It takes eare of numerous jobs of counting both of persons and of objects It is used for sorting materials according to color It controls factory lights It furnishes an accurate and continuous record of the intensity of smoke issuing from chimneys It serves as an automatic sentinel needing only a person s shadow to set off a burglar alarm The electric ear is another uncannily human by product of radio One of its uses is to turn on an airport s landing lights when it hears the motor roar or siren shriek of a night riding airplane approaching the field Televox the world famous mechanical man who executes orders given over the telephone owes h
26. gt ss i ANT E o c7 ane R3 gt Li Vaciometer A Ri L2 2nd RF Cai gt L3 3rd RF Cail g lee ey R2 L Detector Coil L5 Detector Plate Choke c8 L6 Small Filter Choke GND ei L7 Large Filter Choke c9 Rd SI Ofi and On Switch S2 Voltage Tap Switch C1 2nd RF Tuning Condeoser A 7 ZA f E PLAT C2 3rd RF Tuning Condenser FOLLOW THIS PORTION OF LESS C3 Detector Tuning Condenser DIAGRAM FOR SETS USING VOLUME SCREEN C4 2nd RF Alignment Condenser C5 3rd RF Alignment Condenser CONTROL HAVING RESISTANCES FILAMENT C6 Detector Alignment Condense OF 10 000 AND 5000 OHMS Fig 1 Schematic wiring diagr WWW americanradiohistorv com June 1930 NATIONAL RADIO NEWS 9 LTAGES FOR AVERAGE RECEIVER creen Volts C Volts Plate M A Plate M A Normal Grid Test 60 25 60 25 60 25 60 25 tycle_ Cyclel Cycle Cycle Cycle Cycle Cycle Cycle 70 0 2 5 1 5 3 5 3 5 6 0 6 0 10 0 2 5 1 5 3 5 3 5 6 0 6 0 70 70 2 5 1 5 3 5 3 5 6 0 6 0 E ia ee 27 20 20 45 42 30 30 50 0 50 0 x 45 42 30 30 50 0 50 0 Ra E 56 55 i Set on 115 Volt tap from Plate to Cathode from Grid to Cathode asured from Screen Grid Cathode Note Voltage readings are dependent on the type above values er Pack connector strip and are approximately es 60 Cycle 25 Cycle Tand 1 300 Volts 250 Volts Sand 1 180 Volts 150 Volts 4and1 70 Volts 70 Volts 3and 2 2 55 Volts 2 55 V
27. h the lessons Jack W Allen 1004 Hale St P O Box 221 W Dur ham N C Last week I made 18 00 in about 15 hours out of the week I charge from 81 50 to 2 50 per hour I have lined up two dealers who give me all of their repair and service work If it were not for you I would still be digging ditches When I enrolled it was my starting step to a better job Herbert J Sainsbury 4144 10th Ave N E Seattle Washington You will be interested to know that I have ac cepted a job as Service Man for Montgomery Ward amp Co Have taken care of a number of calls this week and have them all running O K Fred J Dubuque 19 Church Street Oswego N Y I gave out 15 cards and as a result have 9 repair jobs I can tackle any Radio job that comes my way I have every right to be con fident because I am getting the best Radio train ing possible William Orr 34 S Main Ave Scranton Penna I have been doing Radio Servicing and I have done fine I am just working on my 20th lesson now and have already earned 113 80 I have been enrolicd with you only two and one half months Ernest M Zimmerman 980 No Water Street Decatur Illinois It seems that Aladdin rubbed his magic iamp for me Your Course has opened up a new world of mysteries I feel as proud when I send in a lesson as if I were banking money S H John son 406 O Connor Ave Charleston W Va I think the N R I cour
28. iagram is shown in Figure 1 Figure 2 is a diagram showing an actual wiring of the power pack These dia grams will enable the Radio Trician to satisfactorily test the various circuits and determine whether or not they are in good condition Oscillation A receiver which oscillates may howl or squeal steadily or may make this noise only when tuned in on a broad casting station The whistle is loudest as the dial is turned slightly in either direction from the station A strong hiss occurring when the station is tuned in denotes that the receiver is very near the point of oscillation This increases the sensitivity somewhat and will do no harm unless too pronounced Actual oscillation however ruins the perforni ance of the set The following sugges tions will be of assistance in eliminating oscillation from any receiver so affected It must be remembered however that the oscillation may be due to any simul taneous combination of the causes 1 Receiver Ungrounded Some re ceivers due to a certain combination of tubes or other factors may operate per fectly when properly connected to a good antenna and ground is removed or when the ground connection is poorly made The remedy consists in providing the set with a short direct ground lead firmly connected to a water or steam pipe 2 Defective or non uniform tube is a common cause of oscillation The quick est and most certain method of determin ing whether
29. is robot existence to the discovery by radio investigators of certain facts about sound sensitivity This electrical servant will take his place as one of our most useful radio by prod ucts High frequency is a term that is day by day growing in importance By the broadcasting of high frequency power it is possible to fry an egg on a cake of ice High frequency induction furnaces are used for the melting of metals used in special alloys There is also indication that in time high fre quency currents will be used for therapeu tic purposes High frequency knowledge grew out of radio studies Perhaps the greatest by product of radio has yet to be invented There are electrical engineers who predict confi dently that the world will have this in vention at its command before many years have passed This invention is power by radio When it comes wires will no longer be needed as power chan nels To light your home and run your vacuum sweeper you will tune in a power company just as now you tune in a broadcasting station for music Air planes will speed through the sky receiving their power by radio from gen erators on the earth and ships and trains likewise will pick up their power from the air WWW americanradiohistorv com for NATIONAL RADIO NEWS June 1930 National Radio News Published monthly in the interest of N R I students and graduates by the NATIONAL RADIO INSTITUTE 1
30. n ever before Parks Summer camps auditoriums hotels and apartments are good prospects for these jobs Campers picnickers and motorists need portable receivers for vacation use This is a live field offering good oppor tunities The advent of automobile radio is keeping trained men busy installing receivers in cars Every automobile owner planning a long motor trip is a good prospect Owners of Summer camps or cottages spend thousands of dollars every year for additional re ceivers and accessories The majority of these places are not wired creating a real demand for battery sets Here are four fields crammed with money making opportunities Every N R I man should land his share or more of this extra volume of Summer work www americanradiohistorv com June 1930 NATIONAL RADIO NEWS PROGRAM INTEREST BUILDS DEMAND FOR NEW SETS On the cover of this issue an announcer is shown picking up a novel program from the Bronx Zoo New York City This merely shows to what ex tremes broadcasting companies go in digging up an endless variety of interesting and entertaining as well as educational programs for their 50 000 000 listeners Do Radio Tricians realize how important well planned interesting programs are to the Radio in dustry Are you making the most of these pos sibilities in tying up program interest with your Radio sales and service A major part of the Radio industry is dependent upon good Radio programs
31. ndenser 2 mid C21 Filter Condenser 4 mfd Aado Input Franstormer 2 Audio Output Transformer 3 Power Vransformer R1 Volume Control i ui ohms Antenna 2 Volume Control paz ohms R3 Ist RF Screen Resisthr 25 000 ohm R4 2nd RF Grid Resistor 500 ohms R5 3rd RF Grid Resistor 500 ohms R6 Ist RF Bias Resistor 1500 ohms R7 2nd RF Bias Resistor 1500 ohms R8 3rd RF Bias Resistor 1500 ohms R9 Detector Bias Resistor 15 000 ohms RIO RF Center Tap Resistor R11 Voltage Divider Resistor R12 Audia Center Tap Resistor C22 By Pass Condenser ae Orie o eats U23 Detector Plate By Pass Condenser 001 mid am of Bosch Model 48 Receiver WWW americanradiohistorv com 10 NATIONAL R DIO NEWS June 1930 There are however some precautions to be noted the observance of which will enable an exact adjustment to be quickly made 1 The receiver signal comes prefer ably from a modulated oscillator battery or AC operated 2 If no oscillator is available use the signal from a semi distant broadcast sta tion 3 Set the oscillator or select the broadcast station so that the signal may be received at some point between 30 and 40 on the dial or as near to the sec tion as possible below 30 rather than above 40 4 Use both the Station Selector and Clarifier control to tune in the loudest possible signal 5 Use the Volume Control to reduce the signal so it is just
32. olts zonnectors ceiver and through the holes provided in tube shields The method of adjust ing these condensers is given in the fol lowing paragraphs Alignment Adjustment The adjust ment of the alignment condensers should not be attempted until it has been defi nitely determined that the trouble does not lie elsewhere in the receiver The selectivity and sensitivity of the receiver depend on the exact setting of these con densers assuming of course that the rest of the set is in perfect order The actual adjustment of the condensers must be made with the receiver in operation that is while it is actually receiving energy from a modulated oscillator or a broadcast station The principle of the adjustment consists merely of turning the adjustment nut of the alignment con densers until the signal is strongest sa St C7 Antenna Tuning Condenser C8 Antenna Conden er 001 mtd p C9 Ist RF Cathode By Pass Condenser 5 mfd C10 2nd RF Cathode By Pass Condenser 5 mid Cii 3rd RF Cathode By Pass Condenser 5 mid C12 Detector Cathode By Pass Condenser mfd C13 Ist RF Screen By Pass Condenser 5 mfd Cl4 2nd RF Screen By Pass Condenser 5 mid C15 3rd RF Screen By Pars Condenser 5 m d C16 Detector Plate By Pass Condenser 001 mfd C17 Ist and 2nd RF Plate By Pass Condenser 5 mid C18 3rd RF Plate By Pass Condenser 5 mfd CI9 Fiher Condenser mfd CH Filter Co
33. ow it and be able to tell other graduates about our aims Let every one of these words sink in To cultivate the friendly relations among the Alumni of the National Radio Insti tute to foster the spirit of unity and loyalty to our Alma Mater to encourage the Institute in its dissemination of Radio knowledge and to promote the welfare of the members by inter change of helpful information Fraternally yours E A MERRYMAN Secretary N R I Alumni Association WWW americanradiohistorv com NATIONAL R DIO NEWS June 1930 How To Install An By STUART C MAHANAY The installation of Radio receivers in auto mobiles is opening up a tremendous field for trained Radio men Mr Mahanay Editor of Radio News gives some valuable pointers to Radio men who are after this business Read this money making article fellows then get SIDE VIEW OF RECEIVER CASE RUBBER SLINGS Fig 1 Shock absorbers for mount ing the set under the floor boards HE selection and construction of receivers for automobiles present only a part of the job to be accomplished Once the receiver is built the con structor must give thought to its location in the car It is true too that where the set has not as yet been built the amount of space available for it will exert a deciding influence on the type finally chosen It is with this in mind that the following article has been prepared The information presented has been
34. se can t be beat All the students that I ve talked to who have made a suecess in Kadio seem to be N R I trained An N R I man is always popular with set owners Blaney B Blay 601 Columbia Ave Elgin Ilinois I just do Radio work in my spare time now but Ill tackle any screen grid receiver right now and guarantee results I have earned the price of my course over many times R A Reel Bouton Iowa WWW americanradiohistorv com IT S HERE mms treater or Tar am Television has been right around the corner for a long time It looks like it Is here at last from the above picture taken in the first Radio Television theatre in Lincoln Park Jersey City New Jersey Wendell McMahill right ploneer of Television announcers an Don Short left Television camera man are standing beside the complicated mechanism which fs a combinatlon of Radio Broadcastinr apparatus with ultra modern motion pieture camera Illumination for the Televislon camera eye is supplied by a 65 000 kilowatt power supply The image of the speaker is Radioed from the black box behind the televisor eye instead of Imprinting itself upon a negative Philo T Farnsworth young San Francisco invemtor and experimenter shown with his improved Televisor constructed in the Crocker laberatories The white circle is the image screen for reception the microphone being used for talking sequenges WEIS SI AAA IIIS RIA STE KI KKK Miss
35. t are shown here more complicated problem Shielded spark plugs may be substituted for the usual ones or choking resistors of about 50 000 ohms may be inserted in series with the spark plug leads Fig 7 Noises produced by the action of the brushes against the generator s commu tator may be eliminated by shunting a 25 mfd fixed condenser across the relay box to ground Editor s Note The growing importance of this field is evidenced by the prominence of the following concerns making Automo bile Receivers Automobile Radio Corporation 4615 Prospect Avenue Cleveland Ohio American Bosch Mag neto Corporation Springfield Massachusetts Continental Wireless Supply Corporation 60 Newark Street Hoboken N J Crosley Radio Ohio 1420 Wisconsin Blvd Delco Radio Dayton Cincinnati Corporation Corporation Ohio National Inc 61 Sherman Street Mal den Massachusetts Silver Marshall Inc 6405 W 65th Street Chicago II They Have Said The victory of success is half won when one gains the habit of work Sarah A Bolton He who would do some great thing in this short life must apply himself to work with such a concentration of his forces as to idle spectators who live only to amuse themselves looks like in sanity Parkman Nothing is easier than fault finding no talent no self denial no brains no character are required to set up in the grumbling business Robert West
36. u can tune in at that particular time and then you will be presenting your receiver under the most favorable circumstances Bigger and better programs are ahead Popular interest in Radio is growing by leaps and bounds Over half of the people of the United States are still without Radios That explains why around four and one half million sets will be sold this year Now is the time to start lining up your sales and service prospects WWW americanradiohistorv com Top to bottom Dorothy Har rington of the Forty Fathom Trawlers the Senator amp Ma jor of La Palina fame Chic Sale as proprietor of Liberty Bell Gas Station Dora Boesher from Around the Samovar and Ted Husing broadcasting the famous Kentucky Derby Headliners of the air like these and Will Rogers and Amos and Andy create big interest in broadcasting which in turn builds a demand for new Radio receiving equipment By PRODUCTS of Radio Eye Counter OLUMBUS sought a new route to India and found a new world Alchemists failed to find a way to con vert base metals into gold but gave birth to chemistry more precious by far than the world s whole supply of the yellow metal Astron omy grew out of astrology Combustion engineers in the course of experiments found to their surprise that coal contains gases and solids of greater value than the fuel product itself and today the revised family tree of coal has not less than five

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