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SHOOTING FOR THE MOON OHM'S LAW SUCCESS STORY: BOB JONES

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1

journalVOL. 22, NO. 2

MARCH/APRIL, 1965Published every other month by the Na-tional Radio Institute, 3939 Wisconsin Ave.,N. W., Washington , D. C. 20016.Subscription $2.00 a year. Printed in U.S.A.Second class postage paid atWashington, D. C.

Copyright 1965 by National Radio Institute.All rights reserved.

CONTENTS

4. OHM'S LAW

14. SHOOTING FOR THE MOON

16. SUCCESS STORY

18. GATED -BEAM FM DETECTOR

24. WHAT'S NEW?

26. JOB OPPORTUNITIES

28. NEW BOOKS

29. ALUMNI NEWS

ON OUR COVER

Diane Cavitt shows off a "solar steamboiler" developed by space scientists.The flower -petal arrangement of thedevice, developed by Bendix Corp. engi-neers, enables it to use heat from thesun to generate electricity for the op-eration of control and communicationssystems in satellites. Themetal petalsopen to capture solar energy and closewhen enough energy has been stored inthe cylindrical unit (at end of the"handle"), called an energy converter.It can operate even when its satellite isin the shadow of a planet. The spacepower plant operates in a way similarto conventional steam boilers, but usesa liquid metal instead of water. Otheraspects of what's doing in outer space---particularly of television's newrole ---appear on Pages 14 and 15, withphotographs televised from Ranger VIIof the moon's surface, and of the north-eastern part of the United States fromweather satellite Nimbus.

WILLIAM F. DUNNEditor and Publisher

ALLENE MAGANNManaging Editor

T.E. ROSEAlumni News Editor

J.B. STRAUGHNTechnical Editor

MARION TIGERArt Editor

2

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3

EDITOR'S NOTE: This article by the

late Dale Stafford, who was an NRI

consultant, is so clearly and simplywritten that we are reprinting it as a

guide to beginning students.

To the beginning student in electronics,everything is new and strange and wonder-

ful. For a time, he gets along fine, learningnew terms and facts and fitting them in withthe things he already knew, Then he runsheadlong into Ohm's Law and, all too often,falls flat on his face.

For the benefit of those who may have thisexperience, we will try to explore this sub-ject and point out some of the common pit-falls. If you are already well acquainted withOhm's Law, the material in this article willprobably be too elementary to be of muchinterest. It is hoped, however, that the newstudent may find it to be of real help.

To keep the discussion as simple as possible,we will attempt, in this article, to coverOhm's Law first as applied to dc circuits.When Ohm's Law is applied to ac circuits,we must consider the fact that the oppositionoffered to the flow of current in a circuit isnot the same for ac as it is for dc, This makesany attempt to cover both types of circuits ina single discussion rather involved and is aptto create more confusion than it clears up.

BY DALE STAFFORD

It is best for the beginner to learn de circuitsfirst. Then ac circuits are much easier tounderstand.

Actually, there is nothing so very difficultabout Ohm's Law. It is simply a fundamentallaw which explains, or defines, the relation-ship between the voltage, current, and resist-ance in a de circuit. At first glance, thereseems little reason to suspect that it can bea very severe stumbling block for the begin-ner. There is even less to show why somestudents have little or no trouble while others,equally clever, flounder badly before they getstraightened out.

Much of the trouble one sometimes has withOhm's Law may be avoided if he remembersthe following facts: Ohm's Law deals withthree different things. These things are re-lated in a definite way, so closely related,in fact, that the values of any two may beused to find the value of the third. However,no matter how closely they are related, theyare completely different things and are meas-ured in entirely different units of measure-ments.

Once a student has learned just what voltage,current, and resistance are and has learnedto apply the proper units of measurement toeach, he doesn't have too much trouble inusing Ohm's Law. Unfortunately, at the timehe first encounters the subject he is tryingto learn so many new things all at once thatit is difficult to keep them neatly sorted outand get a clear view of the over-all picture.A phrase which describes the situation rather

4

aptly is the old saying about "not being ableto see the forest for the trees."

As a result, he becomes confused and wehear such questions as "How many ohms arethere in a volt?" or "How many volts arethere in an ampere?" The answer, of course,is none. Volts, ohms, and amperes are com-pletely different units of measurement usedto measure different things. We can't say"So many volts equal one ampere" or "Somany ohms equal one volt" any more thanwe can say "Two feet equal one hour" or"two tons equal one mile."

Everyone knows, of course, that when wemeasure anything we must use the correctunit of measurement, feet, pounds, gallons,or whatever the situation may require. Forthis reason, it may seem unnecessary tostress anything so elementary. The troubleis that when the student first starts to studythe subject, he doesn't know either the unitsof measurement or just what it is he is sup-posed to be measuring.

It is not so hard to learn to measure timein hours or distance in miles when one knowswhat time and distance are. If, however, onehad never heard of either, it would be a lotmore difficult, wouldn't it? It is small wonderthen that a stranger to electronics sometimesbecomes confused.

HAVE THREE CONCERNS

In any dc circuit, there are, as already men-tioned, three things with which we must beconcerned. The first is the current flowing inthe circuit. The second is the force whichcauses the current to flow. The third is theopposition which is offered to the flow of cur-rent by the parts which make up the circuit.

Current flow in a circuit is due to the move-ment of electrons through the connectingwires and parts of the circuit. You know thatall matter is made up of extremely smallparticles called atoms. These, in turn, aremade up of even smaller particles calledprotons, neutrons, and electrons. The elec-trons make up the outermost portion of theatoms.

In the atoms of some materials, the electronsare tightly bound like the members of a lovingand happy family and it is extremely difficultto make them leave home. In other materials,some of the electrons in the atoms can beeasily dislodged. In fact, in a good conductorsuch as copper or silver, the outermost elec-trons in the atoms are continually flying offin all directions even when no force is appliedto the circuit.

The vacant spaces in the atoms are filled byelectrons dislodged from other atoms whilethe wandering electrons go on to fill vacantspaces in other atoms which have lost anelectron. Thus, we have countless free elec-trons flying at high speed in all directionsthrough the spaces between the atoms.

When a force is applied to the circuit, thefree electrons all move in one direction.While it is unlikely than any individual elec-tron will move more than a few inches persecond, the force is felt almost instantlyaround the entire circuit. The reason is thatthe instant an electron is forced into motion,it repels the electron ahead of it and forcesit to move. This electron, in turn repels anelectron ahead of it and so on all around thecircuit, The electrons repel each other be-cause they are all negatively -charged parti-cles and, as you know, like charges repeleach other.

The effect is somewhat as if you had a pipefilled from end to end with marbles andsuddenly tapped the end marble with a ham-mer. The marbles would begin to move at afairly slow speed but the shock would travelalmost instantly the full length of the pipe.

However, in an electrical circuit, we get apulling as well as a pushing effect. Wheneveran electron is forced out of an atom, the atomwill then attract a free electron. For thisreason, whenever an electron is forced intomotion, another electron moves up to takeits place. Thus, we have a force pushing andpulling the electrons around the circuit.

This movement of electrons around a circuitis what makes up a flow of current. The unitwhich is used to measure current flow is theampere. An ampere is not a unit of quantitylike a bushel or a dozen. Rather, it is a unitof rate -of -flow like the gallons -per -minuteunit used to measure the flow of waterthrough a pipe.

An ampere represents a certain number ofelectrons flowing past any point in a circuitin one second. The exact number of electronsis not important. You will seldom need toknow this and it is such a large number it ishard to remember.

The force which causes electrons to movearound the circuit is called several nameswhich all mean the same thing. These areelectromotive force, difference in potential,potential difference, electric pressure, andvoltage.

Let's see what voltage means. There will bean electrical pressure or strain existing be -

5

tween two objects if one of them has too manyfree electrons while the other has too few.There will also be a strain existing if bothobjects have too many or too few electronsbut one has more than the other. In any ofthese cases, electrons will attempt to movefrom the object which has the greater num-ber of free electrons to the object which hasthe smaller number. If the two objects areconnected by a conductor, electrons willflowfrom the object having the greater number tothe object having the smaller number untilthe number in each is equal.

When an object has too many free electrons,we say that it has a negative charge or simplythat it is negative. When an object has toofew free electrons, we say that it has a posi-tive charge or that it is positive. When bothobjects have too many electrons, both arenegative but the one having the greater num-ber of electrons is more highly negative thanthe other. When both objects have too fewelectrons, both are positive but the one havingthe fewer number of electrons is more highlypositive than the other.

FLOWS TOWARD POSITIVE

Electrons will attempt to flow from a negativepoint to a positive point, from a negative pointto a point which is less negative or from apositive point to a point which is more highlypositive. The strain of the electrons trying tomove in this way is what we call voltage.

A voltage can be generated in several dif-ferent ways. Two common ways of doing soare by the chemical action of a battery or bythe use of a generator. The latter is a machinemade especially for this purpose and worksby moving a conductor, several of them infact, through a magnetic field. It has a ro-tating part called an armature. This hasseveral slots in which coils of wire are wound.In the frame of the generator are other coils,called field coils, wound on pole pieces ar-ranged around the armature. A de currentflows through these coils, setting up magneticfields across the armature. When the arma-ture turns in these fields, a voltage is gen-erated in the armature coils. The armaturemay be turned by a gasoline engine or somedevice may be used to turn it by using steam,a stream of water, or the wind.

The unit of measurement is the volt. This isthe amount of pressure that is needed to forceone ampere of current through a resistanceof one ohm.

The opposition that a material offers to theflow of current is called resistance. As wepreviously mentioned, some metals such as

copper have a great number of free electronscontinually in motion flying in all directionsthrough the spaces between the atoms. Whena voltage is applied between the ends of awire made of such a metal, a large numberof free electrons travel through the wire andwe have a large flow of current. We say thatsuch a metal has a low resistance.

Other materials, such as a carbon resistor,have a great many fewer electrons in motionbetween the atoms. Thus, when a voltage isapplied between the ends of a resistor, fewerelectrons will travel through the material andthe flow of current is much less than in thecopper wire. We say that such a material hasa high resistance.

The unit used to measure resistance is theohm. It is the amount of resistance which willpermit a pressure of one volt to cause oneampere of current to flow in the circuit.

Remember, the force which is pushing andpulling the electrons around the circuit isthe voltage and is measured in volts. Theelectrons moving around the circuit makeup the current and the size or rate -of -flowof the current is measured in amperes. Theopposition to the flow of current offered bythe parts and wires of a circuit is the resist-ance and is measured in ohms.

When very large or very small quantities areto be measured, different units of measure-ment may be used. However, the names ofthese units are formed by taking the name ofthe original unit, volt, ohm, or ampere, andcombining it with another word. If you willremember this, these other units should causeyou no trouble.

Now, let's see how the voltage, current, andresistance are related in the simple circuitshown in Fig. 1. Here we have a 6 -ohm re-sistor, R1, connected across the terminalsof a 6 -volt battery. For the sake of simplicity,we will say that R1 represents all the resist-ance in the circuit. Electrons will leave thenegative terminal of the battery and flow up-wards through R1 to the positive batteryterminal.

- 6 VOLTS

0RI6 OHMS

II AMPERE

FIG. 1. A simple dc circuit.

6

The meter, M, shows that the circuit currentis one ampere. This is what we would expectit to be. It takes one volt to force one ampereof current through a resistance of one ohmso it would take six volts to force one ampereof current through a 6 -ohm resistor.

CHANGE PROPORTIONAL

Since the voltage is what causes the currentflow, if we increase the voltage, the currentwill increase and if we decrease the voltagethe current will decrease. The change in thecurrent will be directly proportional to thechange in the voltage. If we double the volt-age by using a 12 -volt battery, the currentwill be doubled and the meter will read 2amperes, If we halve the voltage by using a3 -volt battery, the current will decrease toone-half its original value and the meter willread one-half ampere.

Since the resistance is what opposes the flowof current, the current will also change if wechange the resistance. The change in the cur-rent is also proportional to the change in theresistance, but, of course, in the oppositedirection. The current increases when theresistance is decreased and decreases whenthe resistance is increased.

If we double the value of R1 in Fig. 1, makingit a 12 -ohm resistor, the current will de-crease to one-half its original value and themeter will read one-half ampere. If we cutthe resistance in half by using a 3 -ohm re-sistor as R1, the current will be doubled andthe meter will read two amperes.

DIVIDE THE VOLTS

The fact that voltage, current, and resistanceare related in this way makes it possible forus to use the values of any two of these tofind the value of the third. Suppose, in Fig. 1,page 6, we have no meter to measure thecurrent, but we do know the battery voltageand the value of Rl. We know it takes onevolt to force one ampere of current througha resistance of one ohm. Therefore, wesimply divide the number of volts by the num-ber of ohms to find the number of amperes.Six divided by six gives us a current of oneampere.

Suppose we know that the battery voltage issix volts and the meter shows that the currentis one ampere but we do not know the valueof Rl. We know that for each volt applied toa circuit, one ampere of current will flow ifthe resistance in the circuit is only one ohm.Since we have six volts applied to the circuitbut only one ampere of current, we know theresistance is more than one ohm. We can find

out how much more by dividing the numberof volts by the number of amperes. In thiscase, six divided by one gives us six ohmsas the resistance of the circuit.

Suppose we know that R1 is six ohms and themeter shows that the current is one amperebut we do not know the voltage of the battery.We know that it will take one volt for everyohm of resistance to cause one ampere ofcurrent to flow so we simply multiply thenumber of ohms by the number of amperesto find how much voltage the battery is pro-viding. In this case, six multiplied by onegives us six volts as the voltage of the battery.

SHOWS RELATIONSHIP

We can do the same thing with any other dccircuit so long as we know two of the values.If we know the values of the voltage and re-sistance, we divide the voltage value by theresistance value to find the value of the cur-rent. If we know the values of the voltage andcurrent, we divide the value of the voltage bythe value of the current to find the value ofthe resistance. If we know the values of theresistance and the current, we multiply thevalue of the current by the value of the re-sistance to find the voltage value. Ohm's Law,which shows this relationship between voltage,current, and resistance is usually written inthe form of three simple equations, E = IR,I = E/R, or R =E/I.

Here again is a common pitfall for the begin-ner. To the newcomer in electronics, equationis a strange and frightful word. He is not ex-actly sure what the purpose of an equationis, nor is he used to seeing things expressedin this manner. Therefore he feels that it issure to be very hard to understand.

If the student has seen some of the equationsused by engineers, he can scarcely be blamedfor feeling uneasy. In some of these, thenumber or quantity on one or both sides ofthe equal mark (=) is made up of severalnumbers added together, subtracted from oneanother, or multiplied by each other. How-ever, the simple equations used in Ohm'sLaw are no more complicated than a recipefor making lemonade.

IT'S JUST A RECIPE

There is nothing frightening about a recipe,is there? You know that if you add certainquantities of water, sugar, and lemon juice,you wind up with something entirely different -lemonade. Thus, the equation for this actionmight be written "1 gal. water +2 cups sugar+ juice of 6 lemons = 1-1/8 gal, lemonade."

7

E.?

E. IR

P. 3ouus

FIG. 2. Ohm's Law problem in dc circuit.

These may be the wrong quantities --I nevermade much lemonade --but you can see whatI mean. At any rate the equation simply meansthat one quantity is equal to another. In thisinstance, certain amounts of water, sugar,and lemon juice are equal to a certain amountof lemonade.

The equations used in Ohm's Law are muchlike simple recipes. Call them recipes if itmakes you feel any better. Let's examinethese recipes and see what each of themmean. The first is E = IR. Here E stands forvoltage, given in volts. I stands for current,given in amperes. R stands for the resistance,given in ohms.

The equation E = IR means that the voltageis equal to the current multiplied by the re-sistance of "the number of volts is equal tothe number of amperes multiplied by the num-ber of ohms." The fact that the number ofamperes is to be multiplied by the numberof ohms could be written in any one of threedifferent ways. We could write it: I x R,I (R), or simply IR. Any one of these methodsmean that one number is to be multiplied bythe other. You can see that E = IR is a muchsimpler way of stating that "the number ofvolts is equal to the number of amperes multi-plied by the number of ohms" than it is towrite out the statement.

You may often see this written "volts = am-peres times ohms. This effort by the writerto simplify the discussion is fine except thatit sometimes confuses the new student. Somestudents get the idea that if "amperes timesohms = volts" all three must be different unitsof the same thing just as pints, quarts, and

gallons might be different quantities of water.This is not true, of course. Regardless ofhow the equation is written, it means that ifthe current in the circuit is a certain numberof amperes and the resistance in the circuitis a certain number of ohms, the voltageapplied to the circuit must be a certain num-ber of volts.

Our next recipe is I = E/R. This means thatthe current is equal to the voltage divided bythe resistance or "the number of amperes isequal to the number of volts divided by thenumber of ohms." The fact that a number isto be divided by another can be shown in threeways. We could write it E R which meansthat the first number is to be divided by thelast. We can separate the two numbers by adiagonal line called a slash mark, "/", likethis: E/R. This means that the number aheadof the slash mark is to be divided by the num-ber following it. In the third method, we canwrite one of the numbers, draw a line underit, and put the second number under the line,

Elike this: T This means that the number above

the line is to be divided by the number belowthe line. Thus, we can write the equation,

I = E = R, I = E/R, or I = R. They all meanthat "the number of amperes is equal to thenumber of volts divided by the number ofohms."

Our third recipe is R = E/I. Here, of coursethe slash mark means the same thing as inthe previous equation. Therefore, the equa-tion means that the resistance is equal to thevoltage divided by the current or "the numberof ohms equals the number of volts divided bythe number of amperes."

STICK TO SUBJECT

Remember, when you use these equations thatyou are not saying that a volt is the same asan ampere or that an ohm is the same as avolt. You can no more divide volts by ohmsthan you could divide dollars by apples. Yetyou can divide a number of dollars by a num-ber of apples to find something else which isentirely different . in this case the num-ber which represents the cost of the apples.In Ohm's Law you are simply using the num-ber of volts and the number of ohms to findthe number of amperes or the number ofvolts and the number of amperes to find thenumber of ohms.

Let's try a few more examples just to be surewe know how to use our "recipes." In Fig. 2,we show three simple circuits. In each ofthese, two values are given and we are to

8

find the third. The correct equation for find-ing the unknown value is shown near the dia-gram of each circuit.

In Fig. 2A, the current is given as 3 amperesand the resistance is given as 4 ohms. Weare to find the voltage of the battery. To dothis, we use the equation E = IR. This tellsus that "the number of volts = the number ofamperes multiplied by the number of ohms"so we substitute the number of amperes andthe number of ohms for I and R in the equa-tion. Now it reads E = 3 x 4. Multiplying3 by 4 we get 12 which is the voltage of thebattery.

In Fig. 2B, the voltage is given as 6 volts andthe resistance as 2 ohms. We are to find thevalue of the current. To do this we use theequation I = E/R. This tells us that "the num-ber of amperes = the number of volts divided

by the number of ohms." When we use thenumber of volts and the number of ohmsgiven, we have "amperes = 6 divided by 3"or "I = 6/3." Six divided by three is two sothe current is 2 amperes.

In Fig. 2C, the voltage is given as 12 voltsand the current as 2 amperes. We are to findthe resistance. Here we use the equationR = E/I, which tells us that "the number ofohms = the number of volts divided by thenumber of amperes." When we use the valuesthat are given we have R = 12/2. Dividing 12by 2, we find that R is 6 ohms.

As you can see by these examples, it is notreally so hard to apply Ohm's Law to dc cir-cuits. The only difficulty is in getting headedin the right direction. We hope that we havebeen able to post a few signposts to guidethe stranger to this subject.

Now . . . What about grounding?Inanypiece

of electronic equipment, groundis simply the point of zero potential. Poten-

tial, by the way, is just a five -dollar word forvoltage - they both mean the same thing.

The term ground came from the early days ofthe ac radio. In those sets, it was customaryto connect zero voltage points in the receivercircuits to the chassis. To make sure thechassis did not change in potential, a wirewas run from the chassis to a metal roddriven into the earth. Thus, the name groundoriginally came from earth ground.

Later, it was found that the precaution of con-necting the chassis to earth ground was sel-dom necessary. The metal chassis showed notendency to change in potential when the re-ceiver circuits were connected to it. For thisreason, the connection to earth ground cameto be omitted in a great many cases. However,the name ground was still used whether thechassis was actually connected to the earth ornot.

When ac -dc sets came along, the practice ofmaking connections to the chassis was nolonger advisable. In fact, it was downrightdangerous. Let's see why.

The ordinary ac receiver uses a power trans-former with a center -tapped high -voltagesecondary winding in a full -wave rectifiercircuit Fig. 3A shows a partial schematicof such an arrangement. To simplify the dia-gram, only the plate and cathode circuits of asingle tube, the output tube, is shown.

let's stop for a moment to lookat a phrase wewill want to use - one you will encounter fre-quently in any discussion of electronic cir-cuits. The phrase is "with respect to." Whatwe mean by this is that we are making a com-parison.

RECEPTACLE

POWER \LIN

Before we consider this circuit, however, FIG. 3. Power supplies. A, ac; B, ac -dc.

9

When we say that "the grid is negative withrespect to the cathode," we mean that thevoltage at the grid is negative in polaritywhen we compare it with the voltage at thecathode. If we say that "terminal A is posi-tive with respect to terminal B," we meanthat the voltage at terminal A is positive inpolarity when we compare it with the voltageat terminal B. The phrase "with respect to"points out the particular point in the circuitthat we are using as a reference point for ourcomparison.

0FIG. 4. Ground connection symbols.

Now, let's get back to our power supply. Whenthe voltage across the secondary windingmakes the upper end of the winding positivewith respect to the lower end, the upper plateof the rectifier is positive with respect to thecathode while the lower plate is negative.

Electrons leave the cathode and travel to theupper plate and through the upper half of thesecondary winding to the center -tap. Fromhere, the path is through the chassis to thelower end of the cathode resistor, up throughthe resistor and tube, down through the out-put transformer primary and through the fil-ter choke back to the cathode.

During the next half -cycle of the ac voltageacross the secondary winding, the lower plateof the rectifier is positive while the upperplate is negative. Electrons travel from thecathode to the lower plate and through thelower half of the secondary winding to thecenter -tap. From here, the path is the sameas during the preceding half -cycle.

Electrons leave the power supply at thecenter -tap and return to the cathode of the

If

0FIG. 5. dc potential.

TOCENTER

TAP

0

rectifier. Thus, we may consider these pointsthe negative and positive terminals of ourpower supply much like the negative andpositive terminals of a battery used for thesame purpose. The grounded center -tap isthe zero -voltage reference point for all theB+ voltages in the receiver.

In this power supply, we have a completecircuit through our power supply and theoutput tube that is isolated from the ac powerline by the transformer. Things do not workout this way with an ac -dc set, however. Let'slook at Fig. 3B.

The only way we can trace a complete circuitis from the cathode of the rectifier to theplate, to the filament tap, through part of thefilament to the upper wire of the line cordand on to one prong on the plug. From here,the path goes along the ac power line, throughthe generator in the power plant, back alongthe ac line to the other prong on the line cordand through the on -off switch to terminal A.

FIG. 6. Grid circuit.

From terminal A, the path is to the lower endof the cathode resistor of the output tube,through the tube and the primary of the out-put transformer to the filter resistor and tothe rectifier cathode.

Since there is no other way to complete thecircuit, we have to use one side of the ac lineas the negative terminal of our power supply.If we made our ground connections to the chas-sis, we would also have to connect the ac lineto the chassis by grounding terminal A.

One side of the power line is grounded toearth ground as shown. As long as the plugis always inserted in the position shown,everything will be all right. The chassis willbe at zero potential.

Suppose, however, that the plug is turned overso that terminal A is connected to the hotside of the power line. Then there would bea difference in voltage of 120 volts betweenthe chassis and earth ground. If one touchedthe chassis and, at the same time, touchedsome grounded object, he could be badly oreven fatally shocked.

10

This problem is solved by the use of a com-mon negative circuit called B-, which is iso-lated from the chassis. One wire of the linecord is connected to one of the terminals ofthe on -off switch. From the other terminal,terminal A in Fig. 3B, a circuit leads to aseries of insulated terminals throughout thereceiver. Connections, which in an ac re-ceiver would go to the chassis, go to theseinsulated terminals instead. In referring tothis common negative circuit, we call it B-.When we speak of ground, we normally meanchassis ground or earth ground.

The symbols used for ground connections areshown in Fig. 4. The one in Fig.4A indicatesa connection to the chassis. It is used on aschematic diagram when a few of the con-nections go to the chassis and the rest go toB-.

The one shown in Fig. 4B may stand for aconnection either to chassis ground or toB-. When used on a diagram along with thesymbol shown in Fig. 4B, it indicates a con-nection to B-. However, when all the groundconnections go to the chassis, this symbolis used instead of the one shown in Fig. 4A.Thus, this symbol could stand for a connec-tion to either the chassis or B-.

If you are working on a receiver, you canlook to see how the connections are made.However, if you are just looking over a dia-gram and don't have the receiver, the easiestway to be sure what it means is to look at thenotes on the diagram. On the schematic, youshould find a note telling you whether the volt-ages were measured to the chassis or to B -(the note may say common negative).

The de voltages in a receiver may be eitherpositive or negative with respect to ground.It all depends on the direction of current flowin the ground connection. Let's look at Fig. 5.Here, again, we have used only a oartial sche-

El.

FIG. 7. RF ground.

matic to simplify the drawing. It is the sameas the one in Fig. 3 with this exception.

In this set, we'll say we need a source fora small negative voltage to provide bias forsome of the tubes. For this purpose, thecenter -tap of the secondary winding was liftedfrom ground, and resistor H2 was connectedbetween the center -tap and ground.

Current flows from the center -tap to groundthrough resistor R2 so the voltage dropacross the resistor has the polarity shown.As you see, terminal C is negative with re-spect to ground.

FLOWS TO CATHODE

Resistor R2 is the cathode resistor of theoutput tube. In this resistor current flowsfrom the chassis to the cathode. The voltagedrop across resistor R2 has the polarityshown on the diagram and terminal A is posi-tive with respect to ground.

To show this more clearly, the two resistorshave been redrawn in Fig. 5B. As you cansee, the ground connection, terminal B, ispositive with respect to terminal C but it isnegative with respect to terminal A.

Now, let's look at Fig. 6. Here you see thegrid and cathode circuits of a tube. As youcan see, the lower end of the grid resistorgoes to ground. There are two reasons forthis. Let's take them one at a time.

First, we want any ac signal voltage appear-ing across the grid resistor to be applied be-tween the grid and cathode of the tube. Thelower end of the cathode resistor is grounded,so we also ground the lower end of the gridresistor. The cathode bypass capacitor by-passes the signal around the cathode resistorso that only the signal voltage appearingacross the grid resistor is applied betweenthe grid and cathode.

The second reason is that we want to keepthe grid at the proper de potential with re-spect to the cathode. The bias for the tube isprovided by the voltage drop across the cath-ode resistor. Current flowing upward throughthis resistor makes the upper end positivewith respect to the lower end. Thus, the volt-age at the cathode is positive with respect toground by the value of the voltage drop acrossthe cathode resistor.

When we connect the lower end of the gridresistor to ground, the grid will be at dcground potential. The grid can't attract elec-trons from the cathode, which is positive, sono dc current will flow in the grid resistor.

11

FIG. 8. Filament circuit.

With no de current flowing in the resistor,there will be no dc voltage drop across it.Therefore, the de potential at the upper endof the resistor will be the same as at thelower end.

Since the cathode is positive with respect toground, it will be positive with respect to thegrid, or to say it differently, the grid is nega-tive with respect to the cathode.

We get into a different type of ground con-nection when we deal with rf ground potentialor signal ground potential. The two phrasesare used to describe the same thing.

When we say that some point in a circuit isat rf ground potential, we mean that it is atground potential only so far as an rf signalis concerned. So far as dc is concerned, itmay have any potential. Therefore, the acsignal must be grounded in a way that doesnot short out any de voltage present.

Suppose, for example, we want to ground thelower side of the plate tuned circuit in thei-f amplifier shown in Fig. 7. We need a con-nection from the lower side of this circuit tothe cathode. This is to complete that portionof the ac plate -cathode circuit that lies out-side the tube and to prevent resistor R frombeing part of the signal plate load.

Since the cathode is grounded, we can com-plete the rf circuit by grounding terminal A.A direct connection to the chassis would shortout the power supply. We can, however, usea capacitor.

The reactance of a capacitor is given by theformula

Xc - 127rfC

where f is the frequency in cycles and C isthe capacity in farads.

All we need to do is find a capacitor that hasa much lower reactance than the ohmic valueof resistor R at the frequency of the signaland connect the capacitor from terminal A tothe chassis. By doing so, we ground the lowerend of the tuned circuit for rf without shortingout our dc voltage.

In most inexpensive sets, this capacitor isomitted and the connection is made throughthe output filter capacitor.

USED TO COMPLETE CIRCUIT

Another way in which ground connections areused is in completing one side of a circuit (ora number of circuits). You know that whenelectrical energy is to be used to operate anydevice, one must have a complete circuitfrom the source of the energy to the load andback to the source. This is true whether weare going to use de or ac to operate the de-vice. In many cases, we can ground one sideof our source and one side of our load andcomplete one side of the circuit through thechassis. This greatly simplifies the wiringof a piece of equipment.

Let's look at Fig. 8. Fig. 8A shows the fila-ments of five tubes that we want to operatein parallel from the filament winding of thetransformer. To connect each filament in-dividually to the filament winding would re-quire a wire from the top of the winding tothe filament and another wire from the otherside of the filament to the lower end of thewinding.

In Fig. 8B, we have simplified things a littleby connecting one side of each filament to thetop of the winding and running a wire fromthe other side of each filament to the lowerend of the winding. However, things are stillpretty badly cluttered up.

In Fig. 8C, we have helped things a little.more by running a single wire from the topof the winding to one side of each filamentand another single wire from the lower sideof the winding to the opposite side of eachfilament.

We can do even better, however. Look at Fig.8D. Here we have grounded the lower end ofthe filament winding. Then we ground one

12

side of each tube filament. After that, a singlewire is used to connect the top of the filamentwinding to the ungrounded side of each fila-ment, and we're in business. One side of thefilament circuit for each tube is completedthrough the chassis.

It may seem that with currents flowing in alldirections through the chassis, the electrons

O

FIG. 9. 9. A, right ground connection; B, wrong.

would become completely lost and wind upalmost anywhere except where they wereheaded. Actually, this does not give as muchtrouble as one might expect.

The number of electrons flowing into a par-ticular point in a circuit can't be any greaterthan the number of electrons leaving thatpoint. m any of tne tiny currents, the numberof electrons arriving is great enough to takethe place of those that are leaving. Therefore,there is no tendency for one current to at-tract electrons from some other current. Sothe currents do not mix as long as a reason-able separation between them is maintained.

It is possible to cause mixing by improperchoice of ground connections. Look at Fig.9A. Here we have three ground connectionswith currents flowing from terminal A toboth terminals B and C. So long as the cur-rents are separated like this, no mixingresults.

Suppose we move the connection at point Bto another point on the chassis, as shown inFig. 9B, so that the current flowing from Ato C has to flow very close to terminal B. Inthis case, we are going to have mixing andpossible trouble.

For this reason, you should not (Mange groundconnections around, indiscriminately. If youmove a ground connection, be sure you knowexactly what you are doing.

Be careful moving ground connections, makesure ground connections are made when theyare needed, and be very, very careful ofaccidental grounds. Happy grounding.

iiiemoriarnMrs. James Ernest Smith, 83,wife of the founder of NationalRadio Institute and mother of itspresident, James MorrisonSmith, died January 29 after abrief illness.

Also surviving are two daughters,Mrs. Guilford Galbraith ofDallas, Texas, and Mrs. B.Robert Sarich, McLean, Va.;eight grandchildren and fourgreat grandchildren.

Mrs. Smith, the former SarahMorrison, was a graduate ofWashington School of Law, andwas admitted to practice beforethe District Bar. She was a mem-ber of the legal fraternity, KappaBeta Pi, and a charter memberof the Washington Readers Club;a member of the ShakespeareSociety, and was the first presi-dent of the Washington Chapterof the Ladies of the Round Table.She was a member of the West-moreland Congregational Churchand of its women's guild.

'04

She and her husband, who had beenmarried 54 years, had visitedevery state in the U. S., and hadmade numerous trips abroad, re-turning from an extensive tourin the Far East and India only a

m-1, few months ago.

To her very active family, civic,and social life she contributedher inherent charm, distinction,and vivacity. As one NRI em -

4=} ployee said after meeting her atits 50th anniversary luncheon,"She was the sort of person youmeet once and never forget."

4- 4.

13

not

E

U

TS

T

ES

TV's New Role

SHOOTING for THE MOONhailed by scientists as the most dramatic forward leap in astron-

omy since Galileo first directed his telescope toward the heavens: theextension of man's vision to within a few hundred yards of the moon'ssurface by means of a high resolution 6 -camera TV system carriedaboard a complex and ingenious space vehicle. . . . In one stroke,electronics and space technology transcended by 2,000 times the limitof resolution of the most powerful earth -bound telescopes to providein more than 4,000 pictures information needed for landing men onthe moon."

Photos and excerpts from Telerision In Space'Courtesy tiCA and Electronic 1ge

El?Hanger VII neared the moon's surface. Altitude: top left.180 miles. right 23.5 miles: renter left. 85 miles. right 34

miles: bottom left, 12 miles. right 3 miles.

I II.H FROM THE TOP . . . This image telerised front the .Nimbus treother sot-ellite shows a larf.fe part of the northeastern Cnited Stales.

The news of two more Ranger shots ---oneby now most likely completed, and the

other scheduled for later this month-givesan exciting new acceleration to the programof landing men on the moon.

And that isn't all ---also in the NASA worksare two more lunar reconnaisance projectsafter Ranger flight results are assayed.There's Project Surveyor, designed to de-posit TV camera and other equipment on themoon for on -the -spot observation; ProjectOrbiter, which is designed to circle the moonwith camera -carrying satellites. More TIROSand Nimbus (weather satellite) vehicles, TVcamera -equipment manned flights (so far onlyrobots which disintegrate on impact havebeen used), and the Orbital AstronomicalLaboratory are among other planned pro-grams.

Much has been discovered, although it'll takemonths and perhaps years yet to properlyevaluate the findings. Too, the dust has notsettled yet on such things as the nature of themoon's surface, and how robot findings willrelate to man.

What is established is television's new role,one undreamed of not too long ago in its stillinfancy, in outer space. If the Hanger moonshots and the following Nimbus flight hadn'tbeen so spectacularly successful, the entireprogram would have had severe setbacks.That "will eventually include not only theobservation of the earth and moon but alsothe study of planets at close range, the scan-ning of the universe through space environ-ment, and channels of communication linkingastronauts visually with their bases on earth"

"Two statistics demonstrate the potential oftelevision in space. Beginning with....Tiros Iin 1960, nearly 42,000 television pictureshave been sent to earth from satellites andother spacecraft. Yet this vast output hascome from only 26 cameras....The flood ofvisual information will mount in the nearfuture with the launching of additional....vehicles.

"Unlike conventional TV cameras, those sofar used to scan weather and lunar featureshave provided a succession of still photosrather than moving images of broadcast TV,"

15

SUCCESS

STORY

BY STEVE BAILEY

REGISTERED TV REPAIR484-1138

MOBILE REPAIR SHOPALL WORK COMPLETED AT YOUR HOME

.FASI DEPENDABLE GUARANTEED SERVICE

A-

Graduate

Registers

An IdeaThousands of NRI graduates are actively employed in radio Indtelevision servicing in shops all over the country. A good manyare operating their own businesses. Thus, it is not surprisingthat an NRI graduate would develop a unique method to improveand modernize service to the customer. In this case, thegraduate is Bob Jones of Fort Bragg, North Carolina. His de-velopment is a mobile TV repair service for registered cus-tomers.Bob is a veteran of 24 years of Army serv-ice. Four years before he planned to retire,the day came when he had to consider whathe was going to do after leaving the Army.He first wanted to choose a secure and profit-able career. He chose television repair. Thenext decision was where to get the besttrain-ing. He chose NRI.

During the next four years, he was trans-ferred twice. However, he pursued his train-ing vigorously and was soon rewarded withhis NRI Diploma. This enabled him to obtaina bench job doing television repair immedi-ately upon retirement from the Army. Hestayed at this for a year, during which timehe obtained valuable practical experience.

It was also during this year that Bob learnedthe ins and outs of the repair business. Herealized that he would have to improve onthe services already offered by local shops

in order to make a successful business ofhis own. After giving much thought to this,the idea of a mobile, registered TV repairservice came to him.

His first move was to purchase a ChevroletStep -Van with a 12 -foot body. He and a friendthen installed shelves, a workbench, andstorage space. Six electrical outlets on theworkbench insured facilities for as muchequipment as necessary to complete any re-pair job. For power, Bob simply installed a30 -foot extension cord that could be pluggedinto one of the customer's electrical outlets.With work completed on the van, Bob nextinstalled his test equipment, which includedeverything from a vacuum tube voltmeter toa B and K 1076 Analyst. He even installedfile cabinets to keep his Sam's Photofactsright on hand.

Bob's next step was to advertise. He adopted

16

the policy, still in use, of sending potentialcustomers a letter of introduction describinghis business along with photographs of hismobile shop. Included in his advertisementis the small card that makes his serviceunique.

The card he sends is a registration card. Itis perforated in the middle so as to be de-tachable. One section contains a self-addressed business reply card on one sideand a form on the other. The customer fillsin his name, address, and telephone number.Also, he fills in the make and model numberof his television set and any other equipmenthe has. Then all he has to do is to mail thecard. Bob even pays the postage on it. Theother section of the card can be attached tothe back of the customer's set. It identifieshim as a registered customer. Also, it hasBob's telephone number on it so the customercan locate it quickly, He can call any time,day or night, since Bob has a 24 -hour an-swering service available seven days a week.

As soon as the card is received, Bob regis-ters the new customer. He then checks to besure he has a Sam's Photofact on the cus-tomer's set. If he doesn't have it, he gets it.Then he checks the schematic to be sure he

has all the parts necessary to do an on -the -spot repair job whenever he is called upon.Since every set is registered, he has advancenotice and can be fully prepared to do a first-rate job at any time. All parts needed are inthe mobile shop ready for use long beforeany defects occur.

The idea of a registered TV service is cer-tainly progressive in that it allows the serv-iceman to be prepared to handle any com-plaint quickly and efficiently. Add to this thebenefits of repairing the set at the customer'shome and you have an unbeatable combination.Needless to say, a satisfied customer is thebest means of adding new customers.

Bob Jones is to be commended for his im-aginative idea, He has successfully demon-strated that the business of Radio -TV serv-icing can always be modernized and stream-lined to keep up with the advancing times.Respect for the local Radio -TV servicemanwill continue to grow as long as graduatessuch as Bob are serving the public.

What are YOU doing with your NRI training? If youhave an unusual story to tell, we'd like to hear it.Write Managing Editor, NRI Journal, 3939 WisconsinAve., N.W., Washington, D. C.

SEND TO:

NRI BOOSTERS' CLUB

National Radio Institute3939 Wisconsin Ave., N.W.

Washington, D.C. 20016

FOR

NRI GRADUATESWe are preparing a directory of NRI graduates who have

benefited as a result of NRI training. If you would

like your name listed, please fill out this

application. Use of your name will bring a reward.

Circulation and distribution of the NRI Graduate

Directory will be subject to your approval.

There is still time to forward your name to us.

Name

NRI Graduate Number

Address

City State_

Area Code Phone No

17

Device OfThe Month:

Anew, better and simpler FM detector forsound channel of TV sets, FM broadcast

receivers, and FM mobile radio system re-ceivers employs only one tube and can reducereceiver tube requirements by as many asthree tubes. The gated -beam tube performsthe functions of IF limiter, FM detector, andaudio amplifier. Heretofore, the Foster -Seeley type FM discriminator has been usedin most high quality FM receivers and TVsets as well as in FM mobile radio systemreceivers. Other substitutes for the standardFM discriminator, such as the Bradley,Beers, and ratio detectors have been used.

B+

GATED -BEAMFM DETECTOR

BY LEO G. SANDS

tector. But their opposition seems to bebased on either ignorance of the facts orunwillingness to learn new techniques.

The standard FM discriminator used in mostFM mobile receivers, as well as FM broad-cast receivers, requires at least two limiterstages ahead of it, plus an audio voltage am-plifier between it and the audio power ampli-fier. A meter is required when zeroing thediscriminator on an incoming or shop refer-ence signal. (See Fig. 1.) Often it is adjustedimproperly and is more effective on a signal

OUTPUTAUDIO

C)

NOTE'

0 METER CONNECTED HERE FOR MAXIMUM VOLTAGE WHEN ADJUSTING LIAND FOR ZERO VOLTAGE WHEN ADJUSTING L2 AGAINST UNMODULATEDSIGNAL.

FIG. 1. Conventional FM discriminator.

In spite of the excellent performance that canbe obtained with these detectors, none cameanywhere near achieving the popularity of thestandard FM discriminator.

But the gated -beam FM detector is rapidlygaining acceptance, not only in TV receivers,but in FM broadcast and communications re-ceivers. Many mobile radio service tech-nicians were prejudiced against the Bradleydetector when it was introduced by Philcoin its mobile radio equipment back in 1948.Many now still oppose the gated -beam de -

at one frequency only, and produces distor-tion on signals that are slightly off the fre-quency to which it was adjusted.

It should be adjusted for zero output when anunmodulated signal is fed to it which is at theexact center of the receiver's IF bandpass.This is the correct adjustment when the in-coming signal is at exactly the correct fre-quency and all of the receiver 's local oscilla-tors are at the right frequency. Any errorin these signals causes a change in the fre-quency of the IF signal fed to the discrimi-

18

I -FAMPLIFIER

ADJUST FORMAXIMUM DC VOLTAGEACROSS RESISTOR R

B+

CI

kCONNECTMETER

------I HERE FORI -F ALIGNMENT

B+

AUDIOOUTPUT

ADJUST FOR4r-0-MAXIMUM AUDIO

AT LOUDSPEAKERCal

LI

FIG. 2. Gated -beam FM detector/limiter/audio amplifier.

nator. When there are no frequency errors,the IF signal fed to the discriminator shouldbe at the IF bandpass mid -frequency, such as290 kc, 455 kc, 1650 kc, etc., depending uponthe receiver design.

Service technicians often use an off -the -airsignal when zeroing the discriminator and"net" all receivers in a system to the samesignal. As a result, the discriminator maynot be zeroed at the center of the IF band-pass and one sideband of the FM signal maybe clipped. As the various transmitters inthe system vary from their correct frequen-cies as much as plus and minus 800 cps,still remaining within FCC tolerances, theadjustment of the discriminators in the re-ceivers is no longer correct unless the re-ceivers are equipped with AFC.

The gated -beam FM detector, on the otherhand, is not critical in adjustment. Its re-sponse curve is such that one adjustmentremains essentially correct within the fre-quency drift tolerances of transmitters andreceivers. Adjustment is very simple. Nometer is required. Simply adjust one coilslug for maximum audio volume. The signalmay be an off -the -air modulated signal or afrequency modulated signal from a signalgenerator.

Fewer components are required in the re-ceiver. The gated -beam tube combines thefunctions of the IF limiter, FM discriminator,and first audio amplifier. As shown in Fig. 2,

the IF signal is fed into the tube's controlgrid through a conventional IF transformer.A special transformer with a tapped sec-ondary is not required. However, anothertuned circuit is required, L1 -C1 in the dia-gram, which is known as the quadrature tunedcircuit.

The schematic symbol for the gated -beam isthe same as for a conventional pentode. Thereare three grids, In a pentode, these are thecontrol grid, screen grid, and suppressorgrid. In a gated -beam tube, the grids areknown as the control grid, accelerator grid,and quadrature grid. In the diagram, theyare identified as 1, 2, and 3.

In a pentode, the suppressor grid has but smalleffect on plate current. But, in a gated -beamtube, the quadrature grid has almost as mucheffect on the plate current as the control grid.When both grids 1 and 3 are positive, platecurrent flows. When either is only a little bitnegative, plate current ceases. In both typesof tubes, grid 2 is maintained at a relativelyhigh positive voltage.

When used as an FM detector, limiting actionis provided by the control grid (1) which isnormally biased negative by only a very smallamount. Some plate current flows. When theincoming signal swings positive, plate cur-rent increases to its maximum amount. Afurther swing in the positive direction willnot cause any further increase in plate cur-rent. When the signal swings negative, plate

19

current is cut off. The resulting plate signaltherefore consists of a train of pulses.

The incoming IF signal applied to grid 1causes a signal voltage to develop acrossthe quadrature tuned circuit (L1 -C1) throughspace charge effect. When the incoming sig-nal is unmodulated, the signal at grid 3 isabout 90° out of phase with the signal at grid1. When the signal is frequency modulated,the signal at grid 3 tends to stay at the signalcenter frequency while the signal at grid 1varies in frequency above and below thecenter frequency.

Thus the phase relationship of the signals atgrids 1 and 3 changes. Maximum plate cur-rent flows when the signals at both grids arepositive and most nearly in phase and viceversa. Plate current thus consists of a trainof pulses whose width depends upon the phaserelationship of the signals at the two grids.The number of plate current pulses flowingper second depends upon the frequency of themodulation. Hence, the average plate currentrepresents the demodulated FM signal(audio). Capacitor C2 smoothes out the pulsesso that a clean audio signal is produced.

The audio recovery of the gated -beam FMdetector is much greater than that of a con-

Att1 -4 -Ca 12 907

'We'll make it up in volume.'

ventional FM discriminator since audio am-plification occurs in the tube simultaneouslywith IF signal limiting and FM demodulation.The gated -beam FM detector has some limi-tations, of course. To obtain optimum per-formance, the tube must be driven hardenough by the IF amplifier. This means thatthe receiver must have ample gain to causeweak signals to drive the gated -beam tubeinto saturation. Thus, in some FM communi-cations receivers, a limiter stage is usedahead of the gated -beam tube, which limitsstrong signals and amplifies weak signals.

Among the gated -beam tubes now on themarket are the 3BN6 and the 6BN6. The truepotentials of the gated -beam tube have notbeen exploited. (I have tried one as an AMdetector and found it to be excellent.) It canbe used in logic circuits, such as OR andAND gates, and as an electronic switch. Theimportant features of the gated -beam tubeare (1) making either grid negative can causeplate current cut off, (2) making both gridspositive causes plate current saturation, and(3) the mutual conductance of the tube isextremely high. The service technician willfind gated -beam FM detectors easy to adjustand service, and the experimenter will findthis tube performs better in many functionsthan conventional tubes.

CREED FOR TODAY

I do not choose to be a commonman or woman. It is my right to beuncommon if I can, to seek opportunity-not security. I do not wish to bea citizen humbled and dulled byhaving the state look after me. I wantto take the calculated risk; todream and to build, to fail and tosucceed. I refuse to barter incentivefor a dole. I prefer the challenges oflife to the guaranteed existence;the thrill of fulfillment to the stalecalm of Utopia. I will not tradefreedom for beneficence nor dignityfor a handout. I will not cower beforeany master nor bend to any threat.It is my heritage to stand erect, proudand unafraid; to think and actfor myself; enjoy the benefit ofmy creation and to face the worldboldly and say: this, with God's help,I have done. All this is whatit means to be an American

20

The Largest Square That Fits In A Cube

PROBLEM: A boy carrying a metal box visiteda machine shop. The inside dimensions of thebox were exactly 1" x 1" x 1" making a vol-ume of 1 cubic foot. The box was open at thetop. The boy was told that he could carryhome the largest square of sheet metal thatwould fit into the box without bending. Thesquare was not to protrude at the top.

Except for the thickness of the metal, whatwere the dimensions of the square?(Solution below.)

BY ROBERT HANES

SOLUTION: In Fig. 1, mark DB = CB, and Solving for X,EA = FA, and call each of these segments X.Triangles FAE and DBC when joined by 47- (i2x)2 = 12 (1 - x)straight lines form a prism. Since they are 1 + 2x2 = /2 - 12xisosceles right triangles, CD = i2 x and the 1 + 2x2 = 2 - 4x + 2x2line CF, a side of the metal square, is a 4x = 1diagonal of the rectangle CEEF, Fig. 2. =

1

and therefore CF = /14 + ( 2x)2. CF equalsx 4

CH, the h oteneuse of the triangle CGH, orCF = 2(1 - X). For the side of the metal square,

S = vi(1 - x)2 + (1 - x)2 = 19/16 + 9/16 =1 /1-8

ANSWER: Each side of the square equalseft. = (1.06066 ft.)

4

C

E

FIG. 1. FIG. 2

D

F

"In the old days couples raised large families to get farm labor. I have a newtwist ----raise kids to be plumbers, appliance repairmen, carpenters, etc. It'sthe only way you can get hold of them nowadays."

----Chan Harris in Door County Advocate, Sturgeon Bay, Wis.

21

DEAR STEVE:

In Lesson 7BB, we are given the formula6.28 1 FXC determining capacitancesx re-actance. Also, we are given the formula159'000. Which one is correct?

FXC

E. M., Wake Island

Both of the formulas you have shown arecorrect. The difference is in the way thevalue of the capacitor is expressed.

Whenever you are trying to find the react-ance of a capacitor with a value expressed infarads, you use the formula 6.28 x FXC'F (frequency) is expressed in cycles and C(capacity) is expressed in farads.

If the value of the capacitor you are workingwith is expressed in microfarads, you use

,the formula 159FXC

000. Again, F is expressedIn terms of cycles, but C is expressed interms of microfarads.

Should the value of the capacitor be in micro-microfarads, you can convert to microfaradsby moving the decimal point six places to theleft. You can then use the formula 159,000

FXC

DEAR STEVE:

I would like you to clear up a small problemI encountered in Lesson 5BB.

On page 24, resistor tolerance is discussed.When it is said that a resistor has a tolerance

BY

STEVEBAILEY

of 10% and the rated value is, for example,220,000 ohms, does it mean that the resist-ance is varying between 242,000 ohms and198,000 ohms, or does it mean that it has aset value between these two?

E. L., Calif.

First of all, a 220K resistor should have avalue of 220K, regardless of its tolerance.The tolerance is mainly a measure of its use-fulness.

When we place a resistor in a circuit, we areplacing it there because it contains a neededamount of resistor, However, this resistormay not be exactly at its rated value or it maychange to another value after being in use fora length of time. If it changes beyond a certainpoint, it is of no use to us. So we have thetolerance rating.

If the resistor has a value of 220K, 10%,it can measure as low as 198,000 ohms or ashigh as 242,000 ohms and still be useable.However, if it is higher than 242,000 ohmsor lower than 198,000 ohms, it is no longeruseable.

DEAR STEVE:

Why does an audio signal have to be ampli-tude -modulated to be transmitted? I am study-ing Lesson 2BB at present.

W. W., Kentucky

An audio signal does not have to be ampli-tude -modulated. It can be frequency -modu-lated as well. However, the audio signal mustbe modulated.

Because of the frequency of audio signals,

22

they cannot be directly transmitted. Theyneed a vehicle on which to ride just as anastronaut needs a rocket if he wishes to goto the moon. For radio, the vehicle is thecarrier signal.

In amplitude modulation, the audio signalsvary the amplitude of the carrier. For fre-quency modulation, the frequency of the car-rier is varied.

DEAR STEVE:

According to Lesson 2BB, a primary cellcannot be recharged. Recently, however, Ihave seen several devices on the market thatare supposed to recharge flashlight cellswhich are primary cells. How can this be?

A. M., Texas

Rejuvenation types of units usually consistof a small transformer, a rectifier, and afixed resistor. A small amount of rectifiedac is passed through the dry cell and givesthe appearance of having recharged it.

For a standard dry cell, electricity is pro-duced because of a chemical action betweenthe electrolyte and the zinc case. The zincis slowly eaten away as the battery is used.As this is happening, hydrogen bubbles areproduced which gather around the carton(positive) electrode. Eventually, the bubblessurround the electrode and the battery can-not operate.

Since I have never used this recharging de-vice, I can only assume that the rectified acserves to remove the bubbles, which permitsthe chemical action to continue. Once thezinc has been completely eaten away, how-ever, no amount of recharging will restoreit.

DEAR STEVE:

In Lesson 11, we told that the circuit shownin Fig. 27 is a grounded plate circuit. Theplate, however, is connected to B+, so howis the plate grounded?

B. B., Virgin Islands

In the circuit you mentioned, the plate isconsidered to be at signal ground potential.This means that the plate is grounded as faras the signal is concerned.

The circuit from plate to ground is througha filter capacitor in the power supply. Thiscapacitor has very low reactance at signalfrequencies, so it will offer very little op-position to the ac signal. It is because of

this that we can consider the ac signal to befed directly to ground.

One easy way to recognize a signal of thistype is to notice that the load is in the cath-ode circuit rather than the plate circuit.

CORRECTIONS

(Jan./Feb. column)

3rd letter, final sentence: 1:2 should be2:1

5th letter, formulas: should be

N1- an

Ni 1.66-N2 Z2 N2 - 1

'Turn right this side of my radio tower.

k

11/5140j

23

Ten pinhead -size incandescent lamps in ahalf -inch space are a prime feature of a re-cording unit for graphing produced by BrushInstruments Division, Clevite Corp., ofCleveland. The unit fits into a light beam os-cillograph without disturbing existing analogchannels, permits recording of ten channelsof high-speed events within a half -inch spaceon the chart paper margin. The unitated at the edge of the chart paper with thelamps practically butted up against it. Whena lamp is energized a trace appears on thepaper.

* * *James E. Smith, founder of National RadioInstitute, election to honorary membershipand professor emeritus in HUTRADENA Club(Howard University Training DetachmentNational Army) with citation: "The serviceas technicians that we were able to renderour country in World War I combat with theenemy was due to the special technical train-ing we received under your excellent tutelageas chief instructor . . ."

* *

* * *

The use of ultrasound as a medical tool isbecoming widespread. One recent device is asonar -type machine that "looks" at the prog-ress and size of an unborn baby. A vibratingcrystal, immersed in a water -filled bag rest-ing on the mother's abdomen, sends out high -frequency sound waves (unaudible to humans)in a moving beam. The high-powered B -scanapparatus works like radar, giving a two-dimensional picture of the tissue involved.

* * *

A tiny new mike by Shure Brothers, Evanston,Ill., retains maximum performance and ex-cellent voice characteristics. The new unit,only 2-5/8" in length by 3/4" in diameter,is a moving coil, dynamic type with a flatfrequency response from 50 to 10,000 cps.It has a single impedance that properlymatches any low impedance input from 50 to250 ohms. The output level is -60.5 db (0 db1 mw with 10 microbars.

* * * * * * * * * *

24

* * * * * * * * * * * * * * * *Light -amplifying tubes that permit soldiersto see in the dark without their own presencesbeing revealed will be produced in Springdale,Conn., for the U. S. Army by the MachlettLaboratories, Inc. (subsidiary of the RaytheonCo.). The tubes intensify the natural low levelof night illumination to present a bright image,thus providing the soldier with fire power andmobility comparable to daytime levels.

EXPO, the 1967 World Exhibition in Montreal,plans the use of robots to welcome visitors.The robot will stop in front of you, using hisradar equipment; welcome you in English orFrench and explain what he is, using recordedtalking ability; and then probably move on toa power outlet and recharge his battery. Therobots, however, will not be in the movieimage of man -shaped giants. They are morelike little boxes on wheels. "After all, they'rejust machines," says deputy administratorCommodore C.C.S. Robertson.

* * *

"Fit" Shrinkable Tubing produced by AlphaWire Core, New York City, shrinks under heatto form a tight, mechanical bond that promisesinsulation, protection, and strengthening ofwire, cable, connectors, or components. Itssample presentation is good, too...on appli-cation of a match to the bit of tubing, you can

how it works.* * *

First girl to enroll in the Allis -Chamberscooperative training program for studentengineers in its 40 -year history is MarthaToshner of Milwaukee. Martha, a junior atMarquette in electrical engineering, alter-nates a semester in the classroom with on-the-job training at Allis -Chambers. Picturedwith her here is a 40 -foot impulse generatorfor testing electrical equipment that simu-lates lightning surges of up to 4 million volts.

* * *An automatic fire -detection and prowler -alarm system that links private homes di-rectly with local fire and police departmentsis being mass-produced by WestinghouseElectric Corp., to be marketed by Wafa Corp.this spring. The 24 -hour monitored system,to be offered to home owners at a servicecharge of $19 per year plus installation costs,operates through a network of sensor de-vices ---smoke detectors, fixed temperatureand rate -of -rise detectors ---installedthroughout the dwelling.* * * * *

see

* * *

The secretary who can't locate her boss nowhas an aid in a pocket-size radio receiver.With it in his pocket, her voice goes auto-matically from the phone to the receiverMessage Mate, although there's no attachmentto the phone. A radio base station and elec-tronic coder tie in with building switchboard,with range extending to several miles. It'smarketed by General Electric Communica-tion Products Dept., Lynchburg, Va.

* * *

* * *Fragile electron tubes used in radar andradio transmission systems on the groundand in missiles (valued at $10 to $40 each)are now being packed in juice -size, tab -topcans at Eithel-McCullough, Inc., in SanCarlos, Calif. The tubes, nestled in softpolyurethane foam and sealed in the can,remained unharmed in test drops on a con-crete surface from a three-story building.Cans are produced by American Can Co., withbodies of tin -coated steel plate and tops ofaluminum, Each can is identified as to tubecontent.

* * * * * * * * * * *

25

EMPLOYMENT OPPORTUNITIES

Sperry Gyroscope Co., Syosset, N. Y.,$7,830,438 from Navy for engineering serv-ices related to inertial navigation systemsfor fleet ballistic missile submarines.Link Group, General Precision, Inc.,Binghamton, N. Y. $7 million from GrummanAircraft Engineering Corp. to design, developand produce a Lunar Excursion Module mis-sion simulator for Project Apollo.Canadian Aviation Electronics, Ltd.,Montreal, about $1 million from CanadianPacific Airlines for a DC -8 simulator.Bell Aerosystems Co., Buffalo, $4.1 millionfrom Kollsman Instrument Corp. for naviga-tion and stabilization equipment used in theairborne mapping and survey system.Republic Aviation Corp., Farmingdale, N.Y.,$4,228,572 from Air Force for provision ofmodification kits, engineering services anddata in support of F-105 aircraft.Hewlett-Packard Co., Oscilloscope division,Colorado Springs, $1,166,211 from AF for a30 -millisecond oscilloscope.Philco Corp., Communications and Elec-tronics division, Philadelphia, $1,206,895from Army for VOcoder systems (voicecoders) with ancillary items.Space General Corp., El Monte, Calif.,$3,353,042 increment to a previously awardedcontract from AF for fabrication, assemblyand checkout of Able -Star space vehicles.Radio Corp. of America, Defense ElectronicsProducts, Camden, N. J., $2 million fixed -price -incentive contract from Army forclassified electronic equipment.Boeing Co., Seattle, $2.5 million from NASALangley Research Center, Hampton, Va., fordynamic simulation work on the supersonictransport project, using a modified Boeing707.International Business Machines Corp.,Poughkeepsie, N. Y., $1.9 million from AFfor an IBM 4044/1416 computer system to beinstalled at Cambridge Research Labora-tories, Hanscom Field, Mass.General Electric Co., Syracuse, N. Y.,$36,930,004 letter contract from Navy forsonar sets, spares, data training, and engi-neering services.Philco Corp., Western Development division,Palo Alto, Calif., $5 million initial incrementto a $24.5 million contract from AF for workon the communications satellite.Lockheed - Georgia Co., Marietta, Ga.,$1,032,421 from AF for modification of themalfunction detection and recording systemfor the Hound Dog missile.TRW Space Technology Laboratories, Inc.,

Redondo Beach, Calif., $3,050,000 initial in-crement to a $9,331,700 AF contractfor workon space -ground communications.Sperry -Rand Corp., Univac division, St. Paul,$15 million from Army for electronic com-munications systems.Columbia University, New York, $2,640,000from Navy for continued long-term basicresearch in underwater sound and relatedsubjects to improve submarine detection.Bendix Corp., Mishawaka, Ind., supplemental$3 million from Navy for long lead timematerial for Talos missile guidance, controland airframes.Western Electric Co., Inc., Winston-Salem,N. C., letter contract from Navy witha maxi-mum liability of $1,036,000 for installingsonar classification sets aboard submarines,spare parts, books, and engineering services.United Aircraft Corp., Farmington, Conn.,$4,259,373 follow-on AF contract for the 433Lweather observing and forecasting system.Honeywell, Inc., Minneapolis, $4 million fromNorth American Aviation's Automatics divi-sion for production of accelerometers for theMinuteman II guidance system.Philco Corp., Aeronutronic division, NewportBeach, Calif., $5.6 million from Army forindustrial engineering services for theShillelagh missile system.General Dynamics Corp., Pomona, Calif.,$3.9 million from Army for Redeye missilesystem engineering services.Lockheed Aircraft Corp. Missile and SpaceCo., Sunnyvale, Calif., $3,087,236 from Navyfor repair of Polaris equipment.Avco Corp., Everett, Mass., $1 million initialincrement to a $4.5 million Air Force con -trace for radiation research.Atlantic Research Corp., Duarte, Calif., sup-plemental $4,280,295 from AF for develop-ment of special test vehicles for re-entryvehicles systems.Collins Radio Co., Dallas, Texas.General Dynamics/Convair, San Diego, Calif.Beckman Instruments, Inc., Fullerton, Calif.Sylvania Electric Products, Inc., Mountain

View, Calif.Emerson Electric Co., St. Louis, Mo.Ling-Temco-Vought, Inc., Dallas, Texas.North American Aviation, Inc., Automation

Div., Anaheim, Calif.General Dynamics Corp., Pomona, Calif.Univac Div., Sperry Rand Corp., St. Paul,

Minn.General Motors, AC Spark Plug Div.,

Milwaukee, Wis.Collins Radio Co., Richardson, Texas.

26

Major contracts ($1 minion or more) were recently awarded by govern-ment agencies or major contractors to the Electronics firms listed here.Such large orders frequently require the hiring of additional personnel.Those interested in possible employment should contact the companies.

Space Sciences, Inc., Waltham, Mass., $1million plus, AF, receiving equipment andrelated material.

Dynalectronic Corp., Washington. D. C., $2,-508,377 from Army for services performedin the installation, operation, and maintenanceof Government -owned data -collecting facil-ities.

Opening for student or graduate in electronicsat American Telephone and Telegraph PlantDept. in Monrovia, Md. Apply Mr. Clatterbuck,central office chief, by telephone at 301 865-5410. An Equal Opportunity employer.

Basic electronics instructors needed for Mid-west and West Coast Naval Training Centers.Prefer recent graduates. Men interestedshould send resumes to Mr. Bob Levy,personnel officer, H. L. Yoh Co., Engineeringconsultants, 123 S. Second St., Philadelphia.

Technical Operations, Inc., Burlington,Mass., $2,130,000 from Army for researchand scientific development studies.

Radio Corp. of America, RCA Service Co.division, Camden, N. J., $1,131,100 fromArmy for furnishing personnel, vehicles,spare parts, and equipment required for in-stallation, operation, maintenance, repair andremoval of communication systems and sup-porting facilities.

Telecomputing Services, Inc., PanoramaCity, Calif., $1,199,873 modificationtoa pre-viously awarded cost -plus -fixed -fee contractfrom Army for preparation of data reductionreports on missiles and test vehicles.

Fairchild Hiller Corp.'s Electronic Systemsdivision, Bay Shore, N. Y., $6.2 million fromMcDonnell Aviation Corp. for production ofadditional auxiliary data annotation sets forreconnaissance aircraft.

CONAR ORDER BLANK TO

DIVISION OF NATIONAL RADIO INSTITUTE, 3939 WISCONSIN AVE., WASHINGTON 16, D.C.

PLEASE PRINT

NAME

ADDRESS

CITY ZONE STATE

NRI STUDENT NUMBER

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Quantity Model Name of Item Price Each Total

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27

NEW BOOKSNewest in the Hayden series of applied mathe-matics is GRAPHICAL ANALYSIS: UNDER-STANDING GRAPHS AND CURVES IN TECH-NOLOGY. Author Philip Stein aims his bookat engineering technicians, relating it to needsin present technology. The book's defined(and reached) objectives are: to teach thestudent technician how to correctively andeffectively plot data on various types ofgraph grids used in technology; to developability to read significant information fromcurves and graphs and make predictions fromthem; to teach thinking in terms or rates ofchange, curve bounded areas, and limitingvalues; to find the properties of curves andwaveshapes common in technology; to teachthat graphs are an effective tool in the studyand understanding of laws and phenonema inscience and technology.

(Hayden Book Co., 270 pp., $9.95)

Virtually all standard electronic productssold through distributors are included in thenewly released RADIO -ELECTRONIC MAS-TER catalog, available at parts distributors(Write publisher for list). More than 185,000

items and 12,000 illustrations are used.

(United Catalog Publishers, Inc., 645 StewartAve., Garden City, N. Y.)

To help the service technician update hisknowledge and skills is the new ADVANCEDSERVICING TECHNIQUES in two volumes byJohn F. Rider, Publisher. The first volume,written by Paul B. Zbar and Peter W. Orne,uses effective illustrations to bolster infor-mation on understanding and servicing colorand black -and -white TV, and includes trou-bleshooting procedures utilizing the latesttest instruments.

The second volume, by five authors, coversmaintenance, repair, and troubleshootingprocedures for home audio equipment, in-cluding stereo amplifiers, record changers,tape recorders, and home intercom systems.

(Rider: Vol. I, 298 pp. clothbound, $8.25;Vol II, 192 pp. clothbound, $5.95)

CONAR EASY PAYMENT PLAN TO

Note: Easy payment contracts cannot be accepted from persons under 21 years of age. If you are under 21, havethis sheet filled in by a person of legal oge and regularly employed.

Enclosed is a down payment of $ on the equipment I have listed on the reverse side. Beginning 30days from the date of shipment I will pay you $ each month until the total payment price is paid. Youwill retain title of this equipment until this amount is fully paid. If I do not make the payments as agreed, you maydeclare the entire unpaid balance immediately due and payable, or at your option, repossess the equipment. Youracceptance of this will be effected by your shipment to me of the equipment I have listed.

Date Your written signature

CREDIT APPLICATION

Print Full Name Age

Home Address

City & State

Previous Address

City & State How long at this address?

Present Employer Position Monthly Income

Business Address How Long Employee

If in business for self, what business? How Long'

Bonk Account with Savings Checking

CREDIT REFERENCE (Give 2 Merchants, Firms or Finance Companies with whom you have or have had accounts.

Credit Acct. with Highest Credit(Name) (Address)

Credit Acct. with Highest Credit(Name) (Address)

How long at this address'

28

lum.i-News

David Spitzer PresidentJules Cohen Vice ?residentF- Earl Oliver Vice PresidentJoseph Stocker Vice PresiidentJames L. Wheeler Vice PresidentTheodore E. Rose Executive Sec.

INSTALLATIONS, ASPECTS OF COLOR TV

BRIGHTEN WINTRY CHAPTER MEETINGS

FLINT (SAGINAW VALLEY) CHAPTER -- inorder to give all members an opportunity tolearn more about color Television includingthose working in the factory at nights -- hasbeen holding meetings on Sunday afternoons.Now the men can come during the week or ona Sunday afternoon or both. Under this sys-tem the chapter is averaging two to threesessions per week, which ia worldng out quitewell.

The Chapter owes a debt of thanks to its newmember, John Allen, for obtaining an RCAcolor television receiver for the membersto practice on at several of the meetings.

The Chapter reports its officers for 1965 asfollows: Henry Hubbard, chairman; DonaldDarbee, vice-chairman; Andrew Jobbagy.secretary; Clyde Morrissett, treasurer;James Windom, Jr., sergeant -at -arms;Charles Wotring, entertainment committee;Robert Poll, educational director; LeroyCockrell, photography; Richard Jobbagy,movie operator; Art Clapp, civilian communi-cations radio; Paul Crippen, Leslie Carley,William Duncan, George Martin, John D.Allen, and Robert Newell, membership drivecommittee and planning committee.

HACKENSACK CHAPTER members wereentertained by a lecture, "Accent On Sound,"delivered by Mr. Frank P. Sullivan, Public

Relations Supervisor, New Jersey Bell Tele-phone Company. Using an oscilloscope andtape recording, he showed an electrical pic-ture of sounds ranging from the trill of apiccolo to the wail of a crying baby. He de-scribed the problems in transmitting soundand how many of the early difficulties wereovercome. A reproduction of the first trans -

Saginaw Valley Chapter meetings oflate have been devoted to talks anddemonstrations of the color bar gen-erator and use of degaussing coil.

29

continental telephone call in 1915 was playedalong with the old Edison discs and hi-fistereo recordings.

At the next meeting Cres Gomez spoke on thepublic address intercom system and the signaltracer. The new officers elected for 1965 werethen installed. They are: Matthew Recliner,chairman. Ed Halvey, vice-chairman; Frank-lin Lucas, secretary; and Paul Schaeffer,treasurer.

The Chapter has had tentative plans on demon-stration of automobile radios from Delco, alsolectures on the scope and other test equip-ment.

HAGERSTOWN (CUMBERLAND VALLEY)CHAPTER has set up an ambitious programfor the study and troubleshooting of colorTV sets. This is a timely and practical pro-gram and should prove interesting and profit-able to the members.

At the conclusion of this program the mem-bers expect to undertake a group study pro-gram to prepare for FCC second class tele-phone licenses.

LOS ANGELES CHAPTER has devoted muchof its time to a general study of color TVproblems. Chairman DeCaussin has taken thelead in this program. He has used his B andK Television Analyst in discoursing on thesubject and the members are grateful to, himfor the wealth of practical information he hasbrought them.

Serving the Chapter for this year are: EugeneDeCaussin, chairman; Bill Edwards, vice-chairman; Earle B. Allen, secretary; andTed Lathema, treasurer.

The membership has been following with muchinterest the case of a local corporation whichwas found to be over -charging for televisionrepairs. The upshot of the case was that thecorporation was fined $800.

NEW YORK CITY CHAPTER'S Officers for1965 are: Brother Bernard Frey, chairman;Frank Lucas, executive chairman; AlbertBimstein, first vice-chairman; Charles Vevo,second vice-chairman; Frank Szpiech, sec-retary; and Samuel Antman, treasurer.

Frank Zimmer, formerly executive chair-man, who after thirty years of continuousservice to the chapter decided not to run foroffice again, was presented with a brassplaque in recognition of his "unremitting anduntiring work."

Two of the Howard Sams tape -slide lectures

NYC Chapter chairman Dave Spitzer,left, presented plaque to Frank Zim-mer to commemorate the latter's 30

years' service to the chapter.

were shown: Semiconductor Fundamentalsand Circuits, and Associated Components,which gave considerable opportunity to mem-bers to refresh their memories on manypoints, with some rather stiff design con-siderations thrown in. After this mental feast,coffee and cake were served by Mmes.Zimmer and Spitzer.

Vice -Chairman Albert Bimstein gave a verypractical talk on Picture Tubes and some ofthe connected problems, along with appro-priate cures. There was considerable interestand many questions from the floor, which, to-gether with some very clear diagrams, helpedto give a clear understanding of the subject.

PHILADELPHIA -CAMDEN CHAPTER is onthe ball again in getting new members. Thelatest are William Helkowski and LynwoodWright, both of Philadelphia. Welcome to themembership, gentlemen;

Bill Davis, a member of the chapter, gave anexcellent talk and demonstration on the BandK Television Analyst. The members got agood insight on how to use the instrument ---now they 11 know how to use it when they gettheir own.

As we go to press, the chapter members wereexpected to be guests of the General Electric

30

Company in PhiladeLphia for a program on thetransistor. Secretary Jules Cohen says thatGeneral Electric has produced a course ontransistors which offers great value for themoney. This is of interest because one of thetwo subjects on whichthe Chapter's programsare going to concentrate during 1965 is tran-sistors. The other is color TV.

Except for the vice-chairman and sergeant -at -arms, all of the 1964 officers were re-elected to serve for the current year. Theyare: John Pirrung, chairman; Harvey Morris,vice-chairman; Jules Cohen, recording sec-retary; Joe Burke financial secretary;Charles Fehr', treasurer; George Dolnick,librarian; and Ray Elollenback, sergeant -at -arms.

PITTSBURGH CHAPTER re-elected most ofits officers to serve for 1965. The entire slateis: James L. Wheeler, chairman; Joseph M.IBurnellis, vice-chairman; Jack Fox, record-ing secretary; Howard A. Tate, correspondingsecretary; William F. Samee, treasurer;David C. Benes, William J. Lundy, and GeorgeMcElwain, executive committee.

The above officers were installed by pastchairman Thomas D. Schrader.

SAN ANTONIO CHAPTER members, atten-tion: The Chapter's meeting night has beenchanged from the third Wednesday of eachmonth to the fourth Friday. The change hasbeen In effect since January 22.

The Chapter's 1965 officers are Sam T.Stinebaugh, chairman; Ronald V. Smith, vice-chairman: Harold Wolff, secretary; and JohnC. Chaney, treasurer.

Instead of a regular meeting in December,the chapter favored a dinner for membersand their wives or sweethearts, held aiWolfe's Inn. The dinner was very tasty andthe entire evening most enjoyable. Some ofthe members favor many repeats.

Jesse Delac and Sam Stinebaugh have teamedup to prepare a program on "'TV VerticalCircuits." The different types of vertical os-cillators will be explained and various verti-tical troubLes discussed. Members are askedto bring information on these circuits or anyquestions they want answered.

SAN FRANCISCO CHAPTER has been en-couraging members to bring their tough -dogtelevision sets to the meetings. Peter Wiweland Andy Royal are demonstrating thetroubleshooting and repair of these toughdogs. The members derive a great deal ofhelp and knowledge from these demonstra-tions.

The Chapter held its sixth anniversary Cele-bration at its January 6 meeting. Before thefestivities commenced a short business meet-ing was held and the new officers for 1965were installed. They are: Isaiah Randolph,chairman; Phil Stearne, vice-chairman; J.Arthur Ragsdale, secretary; Willie Hawkins,assistant secretary; Anderson Royal, treas-urer; J. C. Caraway and F. Goodall, financecommittee.

After the business meeting the, party beganwith the ladies who were present serving thegoodies. A huge platter of delicious chickensandwiches and a large homemade cakebrought by Mrs. Hawkins were much appre-ciated. Mrs. Royal brought several cakes and

Obviously (note smi es) San Antonio Chapter's holiday party was a successful event_

31

pies and Mrs. Ragsdale contributed the punch.Isaiah Randolph supplied a generous quantityof hot coffee and other members brought icecream and cookies. Willie Hawkins with hissaxophone and Mrs. Hawkins at the pianosupplied the music for dancing and singingwhich continued until a late hour.

SOUTHEASTERN MASSACHUSETTS CHAP-TER'S slate of officers for this year are:Danuel DeJesus, chairman; John Alves, vice-chairman; Ernest Grimes, secretary; andEdward Becinarz, treasurer.

Back in the fold are two formerly activemembers, Manuel Raposa and Henry Rockon.It goes without saying they're very welcome.The chapter has been pleased to admit a new

DIRECTORY OF LCHICAGO CHAPTER meets 8:00 P. M., 2ndand 4th Wednesday of each month, 666 LakeShore Dr., West Entrance, 33rd Floor,Chicago. Chairman: Frank Dominski, 2646 W.Potomac, Chicago, Ill.

DETROIT CHAPTER meets 8:00 P. M., 2ndand 4th Friday of each month. St. AndrewsHall, 431 E. Congress St., Detroit. Chairman:James Kelley, 1140 Livernois, Detroit,Mich., VI -14972.

FLINT (SAGINAW VALLEY) CHAPTERmeets 8:00 P. M., 2nd Wednesday of eachmonth at Andrew Jobbagy's Shop, G-5507S. Saginaw Rd., Flint. Chairman: HenryHubbard, 5497 E. Hill Rd., Grand Blanc,Mich., 694-4535.

HACKENSACK CHAPTER meets 8:00 P. M.,last Friday of each month, St. Francis Hall,Cor. Lodi and Holt St., Hackensack, N. J.Chairman; Matthew Rechner, 42 CampbellAve., Hackensack, N. J.

HAGERSTOWN (CUMBERLAND VALLEY)CHAPTER meets 7:30 P. M., 2nd Thursdayof each month at the YMCA in Hagerstown,Md. Chairman: Francis Lyons, 2239 BeverlyDr., Hagerstown, Md. Reg 9-8280.

LOS ANGELES CHAPTER meets 8:00 P. M.,2nd and last Saturday of each month, 4912Fountain Ave., L. A. Chairman: EugeneDeCaussin, 4816 Fountain Ave., Apt. 401, L.A.

MINNEAPOLIS -ST PAUL (TWIN CITIES)CHAPTER meets 8:00 P. M., 2nd Thursdayof each month, at the homes of its members.Chairman: Edwin Rolf, Grasston, Minn.

NEW ORLEANS CHAPTER meets 8:00 P.M.,2nd Tuesday of each month at Galjour's TV,

member, Leonard DeMoranville, Congratula-tions, Leonard:

SPRINGFIELD CHAPTER has sustained quitea blow. Howard Smith has forsaken his nativeNew England, having retired and moved toMichigan.

Howard was the organizer of the Chapterback in 1954, was for years its chief guidingspirit, and worked very hard for the chap-ter's welfare. It's a real loss to the member-ship.

As we go to press, the chapter was busy withplans for its annual party. The members al-ways look forward to this for a thoroughlyenjoyable time.

OCAL CHAPTERS809 N. Broad St., New Orleans, La. Chairman:Herman Blackford, 5301 Tchoupitoulas St.,New Orleans, La.

NEW YORK CITY CHAPTER meets 8:30P. M., 1st and 3rd Thursday of each month,St. Marks Community Center, 12 St. MarksPl., New York City. Chairman: Br. BernardFrey, 213 Stanton St.. New York 2, N. Y.

PHILADELPHIA -CAMDEN CHAPTER meets8:00 P. M., 2nd and 4th Monday of each month,K of C Hall, Tulip and Tyson Sts., Phila-delphia. Chairman: John Pirrung, 2923 Long -shore Ave., Philadelphia, Pa.

PITTSBURGH CHAPTER meets 8:00 P. M.,1st Thursday of each month, 436 Forbes Ave.,Pittsburgh. Chairman: James L. Wheeler,1436 Riverview Dr., Verona, Pa. 793-1298.

SAN ANTONIO ALAMOCHAPTERmeets 7:30P. M., 4th Friday of each month, Beetho-ven Home, 422 Pereida, San Antonio. Chair-man. Sam Stinebaugh, 318 Early Trail, SanAntonio, Texas.

SAN FRANCISCO CHAPTER meets 8:00 P.M.,1st Wednesday of each month, 147 Albion St.,San Francisco. Chairman: Isaiah Randolph,523 Ivy St., San Francisco, Calif.

SOUTHEASTERN MASSACHUSETTS CHAP-TER meets 8:00 P. M., last Wednesday ofeach month. Chairman: Daniel DeJesus, 125Bluefield St., New Bedford, Mass.

SPRINGFIELD (MASS.) CHAPTER meets 7:00P. M., last Saturday of each month as shop ofNorman Charest, 74 Redfern St., Springfield,Mass. Chairman: Steven Chomyn, PowderMill Rd., Southwich, Mass.

32

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