».\21
`.l.1..M.....q:....
`
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`

`
`This book is revised and braught up
`to date {at
`irregular intervals) as
`necessitated by technical progress.
`
`THE
`RADIO
`
`HANllBO0K
`
`Sixteenth Edition
`
`WILLIAM ‘I. ORR, W6SAI
`Editor, 16th Edition
`
`The Standard of the Field —-
`
`for
`
`advanced amateurs
`practical radiomen
`practical engineers
`practical technicians
`
`
`
`Published and distributed to the electronics trade by
`
`EDITORS ad ENGINEERS, Ltd. Summerland ,Ca|ifornia
`Dealers: Electronic distributors, order from us. Bookstores,
`libraries. newsdealers order from Baker &
`Taylor. Hillside, NJ. Export (exc. Canada), order from H.M. Snyder 00., 440 Park Ave. $0., N.Y. 16.
`
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`

`
`THE RADIO HANDBOOK
`
`SIXTEENTH EDITION
`
`Copyright, 1962, -by
`
`Editors and Engineers, Ltd.
`Summerland, California, U.S.A.
`
`Copyright under Pan-American Convention
`All Translation Rights Reserved
`
`Printed in U.S.A.
`
`'
`
`The "Radio Handbook" is also available on special order in Spanish and
`Italian editions; French, German, and Flemish—Dutch editions are in
`preparation or planned.
`
`St., Borgerhout, Antwerp, Belgium.
`
`(Spanish) Marcombo, S.A., Av.
`if more convenient, write:
`Outside North America,
`Jose Antonio, 584, Barcelona, Spain;
`(Italian) Edizione C.E.L.I., Via Gandino ‘I,
`Bologna, Italy; (French, German, Flemish-Dutch) P. H. Brans, Ltd., 28 Prins Leopold
`
`Other Outstanding Books from the Same Publisher
`(See Announcements at Back of Book)
`THE RADIOTELEPI-IONE LICENSE MANUAL
`
`THE SURPLUS RADIO. CONVERSION MANUALS
`
`THE SURPLUS HANDBOOK
`
`THE WOELD’S RADIO TUBES (RADIO TUBE VADE MECUM)
`THE WOBLD’s EQUIVALENT TUBES (EQUIVALENT TUBE VADE MECUM)
`THE WORLD’S TELEVISION TUBES (TELEVISION TUBE VADE MECUM)
`
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`
`HANDBOOK
`
`VideolFrequency Amplifiers H3
`
`
`than with other types, except direct coupling.
`The R-C amplifier may exhibit tendencies to
`"motorboat” or oscillate if it is used with a
`high impedance plate supply.
`
`resistance-capacitance coupling is most com-
`monly used,
`there are certain circuit condi-
`tions wherein coupling methods other
`than
`resistance capacitance are more effective.
`
`6-6
`
`Video-Frequency
`Amplifiers
`
`A video-frequency amplifier is one which
`has been designed to pass frequencies from
`the lower audio range (lower limit perhaps 50
`cycles)
`to the middle r-f range (upper limit
`perhaps 4 to 6 megacycles). Such amplifiers,
`in addition topassing such an extremely wide
`frequency range, must be capable of amplify-
`ing this range with a minimum of amplitude,
`phase, and frequency distortion. Video ampli-
`fiers are commonly used in television, pulse
`communication, and radar work.
`Tubes used in video amplifiers must have
`a high ratio of Gm to capacitance if a usable
`gain per stage is to be obtained. Commonly
`available tubes which have been designed for
`or are suitable for use in video amplifiers are:
`GAU6, 6AG5, 6AKS, 6CB6, 6AC7, 6AG7, and
`6K6-GT. Since, at the upper frequency limits
`of a video amplifier
`the input and output
`shunting capacitances of the amplifier tubes
`have
`rather
`low values of
`reactance,
`low
`values of coupling resistance along with
`«peaking coils or other special interstage cou-
`pling impedances are usually used to flatten
`out the gain/ frequency and hence the phase/
`frequency
`characteristic of
`the
`amplifier.
`Recommended operating conditions along with
`expressions for calculation of gain and circuit
`values are given in figure 9. Only a simple
`two-terminal
`interstage coupling network is
`shown in this figure.
`The performance and gain-per-stage of a
`video amplifier can be improved by the use
`of
`increasingly complex two-terminal
`inter-
`stage coupling networks or
`through the use
`of four-terminal coupling networks or filters
`between successive stages. The reader is re-
`ferred to Terman's "Radio Engineer's Hand-
`book"
`for design data on such interstage
`coupling networks.
`
`6-7
`
`Other Intersruge
`Coupling Methods
`
`Figure 10 illustrates, in addition to resist-
`ance-capacitance interstage coupling, seven
`additional methods in which coupling between
`two successive stages of an audio-frequency
`amplifier may
`be
`accomplished. Although
`
`Transformer Transformer coupling, as illus-
`Coupling
`trated in figure 10B,
`is seldom
`used at the present time between
`two successive single-ended stages of an
`audio amplifier. There are several reasons why '
`resistance coupling is favored over transformer
`coupling between two successive. single-ended
`stages. These are:
`(1) a transformer having
`frequency characteristics comparable with a
`properly designed R-C stage is very expensive;
`(2)
`transformers, unless they are very well
`shielded, will pick up inductive hum from
`nearby power and filament
`transformers;
`(3)
`the phase characteristics of step-up interstage
`transformers are poor, making very difficult
`the inclusion of a transformer of this type
`within a feedback loop; and (4)
`transformers
`' are heavy.
`there‘ is one circuit application
`However,
`where a step-up interstage transformer is of
`considerable assistance to the designer; this
`is the case where it is desired to obtain a
`large amount of voltage to excite the grid of a
`cathode follower or of a high-power Class A
`amplifier from a tube operating at a moderate
`plate voltage. Under these conditions it is pos-
`sible to obtain apeak voltage on the secondary
`of the transformer of a value somewhat greater
`than the d-c plate supply voltage of the tube
`supplying the primary of the transformer.
`
`Push-Pull Transformer
`Inrerstuge Coupling
`
`transformer
`Push-pull
`coupling between two
`stages is illustrated in
`figure 10C. This interstage coupling arrange-
`ment is fairly commonly used. The system is
`particularly effective when it is desired, as in
`the system just described,
`to obtain a fairly
`high voltage to excite the grids of a high-
`power audio stage. The arrangement is also
`very good when it is desired to apply feed-
`back to the grids of the push-pull stage by
`applying the feedback voltage to the low-
`potential sides of the two push-pull second-
`aries.
`
`Impedance
`Coupling
`
`Impedance coupling between two
`stages is shown in figure 10D.
`This circuit arrangement is seldom
`used, but it offers one strong advantage over
`R-C interstage coupling. This advantage is
`the fact that, since the operating voltage on
`the tube with the impedance in the plate cir-
`cuit is the plate supply voltage, it is possible
`to obtain approximately twice the peak volt-
`age output that it is possible to obtain with
`‘ R-C coupling. This is because, as has been
`
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`
`THE RADIO
`Vacuum Tube Ampjifilers
`114
`
`
`‘ET
`
`’§7i‘“
`
`E
`
`® RESISTANCE-CAPACITANCE COUPLING
`
`TRANSFORMER COUPLING
`
`
`
`
`
`© PUSH-PULL ‘TRANSFORMER COUPLING
`
`© IMPEDANCE COUPLING
`
`fig"?
`
` +3
`
`® I MPEDANCE-TRANSFORMER COUPLING
`
`® RESISTANCE-TRANSFORMER COUPLING
`
`__
`
`+8
`
`
`
`© CATHODE COUPL|NG
`
`® DIRECT COUPLING
`
`Figure 10
`INTERSTAGE COUPLING METHODS FOR AUDIO FREQUENCY VOLTAGE AMPLIFIERS
`
`
`mentioned before, the d-c plate voltage on an
`R-C stage is approximately one-half the plate
`supply voltage.
`
`Impedance-Transformer These two circuit ar-
`and Resis1'once-TrcIns-
`rangements,
`illustrated
`former Coupling
`in figures 10E and 10F,
`are employed when it is
`desired to use transformer coupling for
`the
`reasons cited above, but where it is desired
`that
`the d-c plate current of theamplifier
`
`stage be isolated from the primary of the cou-
`pling transformer. With most
`types of high-
`permeability wide-response transformers it is
`necessary that there be no direct-currentflow
`through the windings of the transformer. The
`impedance-transformer arrangement of figure
`10E will give a higher voltage output
`from
`the stage but is not often used since the plate
`coupling impedance (choke) must have very
`high inductance and very low distributed ca-
`pacitance in order not to restrict the range of
`
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`

`
`HANDBOOK
`
`Phase Inverters
`
`H5
`
`
`
`same type tubes_ with the values of plate volt-
`age and load resistance to be used for the
`cathode-coupled stage.
`'
`
`the equations in figure 11
`Inspection of
`shows that as the cathode resistor is made
`
`to approach zero, the G3, approaches
`smaller,
`zero,
`the plate resistance approaches the RP
`of one tube, and the mu approaches zero. As
`the cathode resistor is made very large the Gm
`approaches one half that of a single tube of
`the same type, the plate resistance approaches
`twice that of one tube, and the mu approaches
`the same value as one tube. But since the Gm
`of each tube decreases as the cathode resistor
`is made larger (since the plate current will
`decrease on each tube) the optimum value of
`cathode resistor will be found to be in the
`vicinity of the value mentioned in the previous
`paragraph.
`
`,=_
`I
`
`GM
`
`5
`GM 2G+1
`
`c: an GM (1 +—,[,—)
`RK = CATHODE RESISTOR
`R9 Q1 GM=GMOFEACHTUBE
`RP’ =
`G+1
`LI = LI or EACH TUBE
`A
`-RP = Rpor EACH TUBE
`-1.1 fir
`=
`LI’
`EQUIVALENT FACTORS INDICATED ABOVE BY U) ARE
`THOSE OBTAINED BY USING AN AMPLIFIER WITH A PAIR
`OF SIMILAR TUBE TYPES IN CIRCUIT SHOWN ABOVE.
`
`Figure ll
`
`Equivalent factors for a pair of similar fri-
`odes operating as a cathode-coupled audio-
`frequency voltage amplifier.
`
`
`the transformer which it and its associated
`
`tube feed. The resistance-transformer arrange-
`ment of figure 10F is ordinarily quite satis-
`factory where it is desired to feed a trans-
`former from a voltage amplifier stage with no
`d.c.in the transformer primary.
`
`,
`
`Cathode
`Coupling
`
`The cathode coupling arrangement
`of figure 10G has been widely used
`only comparatively recently. One
`outstanding characteristic of such a circuit is
`that
`there is no phase reversal between the
`grid and the plate circuit. All other common
`types of interstage coupling are accompanied
`by a 180° phase reversal between the grid
`circuit and the‘plate circuit of the tube.
`Figure 11 gives the expressions. for deter-
`mining the appropriate factors for an equiva-
`lent triode obtained through the use of a pair
`of similar triodes connected in the cathode-
`
`coupled circuit shown. With these equivalent
`triode factors it is possible to use the ex-
`pressions shown in figure 5 to determine the
`gain of the stage at different frequencies. The
`input capacitance of such a stage is less than
`that of one of the triodes,
`the effective grid-
`to-plate capacitance is very much less (it is
`so much less that such a stage may be used‘
`as an r-f amplifier without neutralization), and
`the output capacitance is approximately equal
`to the grid-to-plate capacitance of one of the
`triode sections. This circuit
`is particularly
`effective with tubes such as the 6J6, 6N7, and
`6SN7-GT which have two similar
`triodes in
`one envelope. An appropriate value of cathode
`resistor to use for such a stage is the value
`which would be used for the cathode resistor
`
`of a conventional amplifier using one of the
`
`Direct Coupling
`
`Direct coupling between suc-
`cessive amplifier stages (plate
`of first stage connected directly to the grid of
`the succeeding stage) is complicated by the
`fact that the grid of an amplifier stage must
`be operated at an average negative poten-
`tial with respect to the cathode of that stage.
`However, -if the cathode of the second ampli-
`fier stage can be operated at a potential more
`positive than the plate of the preceding stage
`by the amount of the grid bias on the second
`amplifier stage, this direct connection between
`the plate of one stage and the grid of the suc-
`ceeding -stage can be used. Figure 10H il-
`lustrates an application of this principle in
`the coupling of a pentode amplifier stage to
`the grid of a "hot-cathode” phase inverter. In
`this arrangement the values of cathode, screen,
`and plate resistor in the pentode stage are
`chosen such that the plate of the pentode is at
`approximately 0. 3 times the plate supply po-
`tential. .The succeeding phase-inverter stage
`then operates with conventional values of
`cathode and plate resistor (same value of re-
`sistance) in its normal manner. This type of
`phase inverter is described in more "detail in
`the section to follow.
`
`6-8
`
`Phase Inverters
`
`It is necessary in order to excite the grids
`of a push-pull stage that voltages equal
`in
`amplitude and opposite in polarity be applied
`-to the two grids. Thesevoltages may be ob-
`tained through the use of a push-pull
`input
`transformer such as is shown in figure 10C.
`It is possible also, without the attendant bulk
`and expense of a push-pull input transformer,
`to obtain voltages of the proper polarity and
`
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`
`268 Generation of R-F Energy
`
`THE RADIO
`
`
`
`OPERATING
`B/AS CUTS
`OFF CLAMP
`TUBE
`
`TU BE
`
`Figure 33
`DROPPING-RESISTOR SCREEN SUPPLY
`
`
`
`The Clamp Tube
`
`A clamp tube may be added
`.to the series screen supply,
`as shown in figure 34. The clamp tube is nor-
`mally cut off by 'virtue of the d-c grid bias drop
`developed across the grid resistor of the ret-
`rode tube. When excitation is removed from
`
`the tetrode, no bias appears across the grid
`resistor, and the clamp tube conducts heavily,
`dropping the screen voltage to a safe value.
`When -excitation is applied to the tetrode the
`clamp tube is inoperative, and fluctuations of
`the plate loading of the tetrode tube could
`allow the screen voltage to rise to a damaging
`value. Because of this factor, the clamp tube
`does not offer complete protection to the tet-
`ro de.
`
`A low voltage screen supply
`The Separate
`Screen Supply may be used instead of the
`series screen dropping resis-
`tor. This will protect the screen circuit from
`excessive voltages when the other
`tetrode
`operatingparameters shift. However, the screen
`can be easily damaged if plate or bias volt-
`age is removed from the tetrode, as the screen
`current will reach high values and the screen
`dissipation will be exceeded.
`If the screen
`supply is capable of providing slightly more-
`screen voltage than the tetrode requires for
`proper operation, a series wattage-limiting re-
`sistor may be added to the circuit as shown
`in figure 35. With this resistor in the circuit
`it is possible.to apply excitation to the ter-
`rode tube with screen voltage present (but in
`the absence of plate voltage) and still not dam-
`age the screen of the tube. The value of the
`resistor should be chosen so that the product
`of
`the voltage applied to the screen of the
`tetrode times the screen current never exceeds
`the maximum rated screen dissipation of the
`tube.
`‘
`
`
`
` NEGA T/I/E
`
`Figure 34
`CLAMP-TUBE SCREEN SUPPLY
`
`
`
`pling. The latter is a special form of induc-
`tive coupling. The choice of a coupling method
`depends upon the purpose for which it is to
`be used.
`
`Capacitive
`Coupling
`
`Capacitive coupling between an
`amplifier or doubler circuit and a
`preceding driver stage is shown
`in figure 36. ‘The coupling capacitor, C,
`iso-
`lates the d-c plate supply from the next grid
`and provides a low impedance path for the r-f
`energy between the tube being driven and the
`driver" tube. This method of coupling is simple
`and economical for low power. amplifier or ex-
`citer stages, but has certain disadvantages,
`particularly for high frequency stages. The
`grid leads in an amplifier should be as short
`as possible, but this is difficult to attain in
`the physical arrangement of a high power am-
`plifier with respect to a capacitively-coupled
`driver stage.
`'
`
`Disadvantages of One
`significant disadvan-
`Capacitive
`tage of capacitive coupling
`Coupling
`is the difficulty of adjusting
`the load on the driver stage.
`Impedance adjustment can be accomplished
`by tapping the coupling lead a part of the way
`down on the plate coil of the tuned stage of
`the driver circuit; but often when this is done
`
`
` 0
`
`LOW VOLTAGE
`SCREEN SUPPLY
`
`+B
`
`l3-l3
`
`lnterstage Coupling
`
`Energy is usually coupled from one circuit
`of a transmitter into another either by capaci-
`tive coupling,
`inductive coupling, or link cou-
`
`Figure 35
`A PROTECTIVE WATTAGE-LIMITING RE-
`SISTOR FOR USE WITH LOW-VOLTAGE
`SCREEN SUPPLY
`
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`
`HANDBOOK
`
`lnterstage Coupling
`
`269
`
`
`
`
`
`Figure 36
`CAPACITIVE INTERSTAGE COUPLING
`
`
`
`a parasitic oscillation will take place in the
`stage being driven.
`One main disadvantage of capacitive coupl-
`ing lies in the fact that the grid-to-filament
`capacitance of the driven tube is placed di-
`rectly across the driver tuned circuit. This
`condition sometimes makes the r-f amplifier
`difficult to neutralize, and the increased mini-
`mum circuit capacitance makes it difficult to
`use a reasonable size coil in the v-h-f range.
`Difficulties from this source can be partially
`V eliminated by using a center-tapped or split-
`stator tank circuit in the plate of the driver
`stage, and couplingcapacitively to the oppo-
`site end from the plate. This method places
`the plate-to-filament capacitance of the driver
`across one-half of the tank and the grid-to-
`filament capacitance of the following stage
`across the other half. This type of coupling is
`shown in figure 37.
`Capacitive coupling can be used to advan-
`tage in reducing the total number of tuned cir-
`cuits in a transmitter so as to conserve space
`and cost. It also can be used to advantage be-
`tween stages for driving beam tetrode or pen-
`tode amplifier or doubler stages.
`
`Inductive
`
`Coupling
`
`Inductive coupling (figure 38) re-
`sults when two coils are electro-
`magnetically coupled to one an-
`other. The degree of coupling is controlled by
`varying the mutual inductance of the two coils,
`which is accomplished by changing the spac-
`ing or the relationship between the axes of
`the coils.
`'
`
`
`
`Figure 38
`INDUCTIVE INTERSTAGE COUPLING
`
`Figure 37-
`BALANCED CAPACITIVE COUPLING
`
`Balanced capacitive coupling sometimes is
`useful when it is clesirableto use a relatively
`large inductance in the interstage tank cir-
`cuit, or where the exciting stage is neutral-
`izecl as shown above.
`
`
`
`Inductive coupling is used extensively for
`coupling r-f amplifiers in radio receivers. How-
`ever, the mechanical problems involved in ad-
`justing the degree of coupling limit ‘the use-
`fulness of direct inductive coupling in trans-
`mitters. Either‘ the primary or the secondary
`or both coils may be tuned.
`
`Unity Coupling
`
`If the grid tuning capacitor of
`figure 38 is removed and the
`coupling increased to the maximum practicable
`value by interwinding the turns of the two coils,
`the circuit insofar as r.f. is concerned acts
`like that of figure 36, in which one tank serves
`both as plate tank for the driver and grid tank
`for
`the driven stage. The inter-wound grid
`winding serves simply to isolate the d-c plate
`voltage of the driver from the grid of the driven
`stage, and to provide a return for d-c grid cur-
`rent. This type of coupling, illustrated in fig-
`ure 39, is commonly known as unity coupling.
`Because of the high mutual inductance, both
`primary and secondary are resonated by the
`one tuning capacitor.
`
`I NTERWOUND
`
`
`
`'
`
`’’UN|TY’’
`
`Figure 39
`INDUCTIVE COUPLING
`
`Due to the high value of coupling between
`the two coils, one tuning capacitor tunes
`both circuits. This arrangement often is use-
`ful in coupling from a single-ended to a push-
`pull stage.
`
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`
`R A Di 0
`T H E
`R—F Energy
`270 Generation of
`
`
`UPPER euos “HOT”
`
`E:B-
`' LINK COUPLING
`AT “com” ENDS.
`
`:
`
`ENDS “HOT”
`
`LINK COUPLING
`AT “COLD" CENTER.
`
`Figure 40
`INTERSTAGE COUPLING BY MEANS
`OF A ’’LINK’’
`
`Link intersfage coupling is very commonly
`used since the two sfages may be separated
`by a considerable distance, since the amount
`of a coupling between the two stages may be
`easily varied, and since the capacitances of
`the two stages may be isolated to permit use
`of larger inductances in the v-h-f range.
`
`
`
`Link Coupling Aspecial form of inductive
`,
`coupling which is widely em-
`ployed in radio transmitter circuits is known
`as link coupling. A low impedance r-f trans-
`mission line couples the two tuned circuits
`together. Each end of the line is terminated
`in one or more turns of wire, or links, wound
`around the coils which are being coupled to-
`gether. These links should be coupled to each
`tuned circuit at the point of zero r-f potential,
`or nodal point. A ground connection to one
`side of the link usually is used to reduce har-
`monic coupling, or where capacitive coupling
`between two circuits must be minimized. Co-
`axial line is commonly used to transfer energy
`between the two coupling links, although Twin-
`Lead may be used where harmonic attenuation
`is not so important.
`Typical link coupled circuits are shown in
`figures 40 and 41. Some of the advantages of
`link coupling are the following:
`
`(1)
`
`(2)
`
`(3)
`
`(4)
`
`(5)
`
`(6)
`
`It eliminates coupling taps on tuned cir-
`cuits.
`
`It permits the use of series power supply
`connections in both tuned grid and tuned
`plate circuits, and thereby eliminates the
`need of shunt-feed r-f chokes.
`It allows considerable separation between
`transmitter Stages without appreciable
`r-f losses or stray chassis currents.
`It reduces capacitive coupling and there-
`by makes neutralization more easily at-
`tainable in r-f amplifiers.
`impedance
`It provides
`semi-automatic
`matching between plate and grid tuned
`circuits, with the result that greater grid
`drive can be obtained in comparison to
`capacitive coupling.
`It effectively reduces the coupling of har-
`monic energy.
`
`Figure 4l
`PUSH-PULL LINK COUPLING
`
`
`
`The link-coupling line and links can be
`made of no. 18 push-back wire for coupling
`between low-power stages. For coupling be-
`tween higher powered stages
`the 150-ohm
`Twin-Lead transmission line is quite effective
`and has very low loss. Coaxial transmission is
`most satisfactory between high powered am-
`plifier stages, and should always be used
`where harmonic attenuation is important.
`
`l3-l4
`
`Radio-Frequency
`Chokes'
`
`Radio-frequency chokes are connected in
`circuits for the purpose of stopping the pas-
`sage‘ of r-f energy while still permitting a di-
`rect current or audio-frequency current to pass.
`They consist of
`inductances wound with a
`large number of turns, either in the form of a
`solenoid, a series of solenoids, a single uni-
`versal pie winding, or a series of pie wind-
`ings. These inductors are designed to have as
`much inductance and as little distributed or
`
`shunt capacitance as possible. The unavoid-
`able small amount of distributed capacitance
`resonates the induct_ance, and this frequency
`normally should be, much lower than the fre-
`quency at which the transmitter or receiver
`circuit is operating. R-f chokes for operation
`on several bands must be designed carefully
`so that the impedance of the choke will be ex-
`tremely high (several hundred thousand ohms)
`in each of the bands.
`
`The direct current which flows through the
`r-f choke largely determines the size of wire
`to be used in the winding. The inductance of
`r-f chokes for
`the v-h-f range is much less
`than for chokes designed for broadcast and
`ordinary short-wave operation. A very high
`inductance r-f choke has more distributed ca-
`
`pacitance than a smaller one, with the result
`
`LAM Ex1017-p. 9
`LAM V FLAMM
`
`IPRZO15-01767
`
`LAM Ex 1017-p. 9
`LAM v FLAMM
`IPR2015-01767
`
`

`
`HANDBOOK
`
`Shunt
`
`and Series Feed
`
`27]
`
`
`
` 1-SG +HV
`
`+SG +HV
`
`PARALLEL PLATE FEED
`
`SERIES PLATE FEED
`
`Figure 42
`ILLUSTRATING PARALLEL AND
`SERIES PLATE FEED
`
`Parallel plate feed is clesirable from a safety
`standpoint since the tank circuit is at ground
`potential with respect
`to d.c. However,
`a
`high-impedance. r-f choke is required, and
`the r-f choke must be able to withstand the
`peak r-f voltage output of the_tube. Series
`plate feed eliminates the requirement for a
`high-performance r-f choke, but requires the
`use of a relatively large value of by-pass
`capacitance at
`the bottom end of the tank
`circuit, as contrasted to the moderate value
`of coupling capacitance which. may be used
`at
`the ‘top of the tank circuit
`for parallel
`plate feed.
`
` ~
`
`that it will actually offer less impedance at
`very high frequencies.
`Another consideration, just as important as
`the amount of d.c.
`the winding will carry, is
`the r-f voltage which may be pl-aced across
`' the choke without its breaking down. This is
`a function of insulation, turn spacing, frequen-
`cy, number and spacing of pies and other fac-
`tors.
`
`Some chokes which are designed to have a
`high impedance over a very wide range of fre-
`quency are,
`in effect, really two chokes: a
`u-h-f choke in series with a high-frequency
`choke. A choke of this type is polarized; that
`is, it is important that the correct end of the
`combination choke be connected to the "hot”
`side of the circuit.
`
`Shunt and
`Series Feed
`
`Direct-current grid and plate
`connections are made either by
`series or parallel feed systems.
`Simplified forms of each are shown in figures
`42 and 43.
`Series feed can be defined as that in which
`the d-c connection is made to the grid or plate
`circuits at a point of very low r-f potential.
`Shunt feed always is made to a point of high
`r-f voltage and always requires a high imped-
`ance r-f choke or a relatively high resistance
`to prevent wasteof r-f power.
`
`
`
`_5.A5
`
`-BIAS
`
`PARALLEL ems FEED
`
`SERIES BIAS FEED
`
`Figure 43
`ILLUSTRATING SERIES AND
`PARALLEL BIAS FEED
`
`
`
`13-15
`
`Parafleland
`Push-Pull Tube Circuits
`
`The comparative r-f power output from paral-
`lel or push-pull operated amplifiers is the same
`if proper impedance matching is accomplished,
`if sufficient grid excitation is available in
`both cases, and if the frequency of measure-
`ment is considerably lower than the frequency
`limit of the tubes.
`
`Parallel
`Operation
`
`Operating tubes in parallel has
`some advantages in transmitters
`designed for operation below 10
`Mc., particularly when tetrode or pentode tubes
`are to be used. Only one neutralizing capacitor
`is required for parallel operation of triode
`tubes, as against
`two for push-pull. Above
`about 10 Mc., depending upon the tube type,
`parallel tube operation is not ordinarily recom-
`mended with triode tubes. However, parallel
`operation of grounded-grid stages and stages
`using low-C beam tetrodes often will give ex-
`cellent results well into the v-h-f range.
`
`Push-Pull
`Operation
`
`The push-pull connection provides
`a well-balanced circuit insofar as
`miscellaneous
`capacitances
`are
`concerned; in addition, the circuit can be neu-
`tralized more completely, especially in high-
`frequency amplifiers. The L/C ratio in a push-
`pull amplifier can be made higher than in a
`plate-neutralized parallel-tube operated am-
`plifier. Push-pull amplifiers, when perfectly
`balanced, have less second-harmonic output
`’ than parallel or single-tube amplifiers, but in
`practice undesired capacitive coupling and
`circuit unbalance more or less offset the theo-
`retical harmonic-reducing advantages of push-
`pull r-f circuits.
`
`LAM Ex1017-p. 10
`LAM V FLAMM
`
`IPRZO15-01767
`
`LAM Ex 1017-p. 10
`LAM v FLAMM
`IPR2015-01767
`
`

`
`Antennas and Antenna Matching
`430
`THE RADIO
`
` 300 OHM “RIBBON” LINE /
`
`
`
`WIRES SHORTED TO‘
`GETHER AT END
`
`COAXIAL
`
`FEED LINE
`
`_
`
`Figure 10
`TWIN-LEAD MARCONI ANTENNA FOR THE
`80 AND 160 METER BANDS
`
`the problem in producing an
`Essentially,
`antenna for lower frequency operation in re-
`stricted space is to erect a short radiator
`which is balanced with respect to ground and
`which is therefore independent of ground for
`its operation. Several antenna types meeting
`this set of conditions are shown in figure 9.
`Figure 9A shows a conventional center-fed
`doublet with bent-down ends. This type of an-
`tenna can be fed with 75-ohm Twin-Lead in the
`center, or it may be fed with a resonant line
`for operation on several bands. The overall
`length of the radiating wire will be a few per
`cent greater than the normal length for such
`an antenna since the wire is bent at a posi-
`tion intermediate between a current loop and
`a voltage loop. The actual length will have to
`be determined by the cut-and-try process be-
`cause of the increased effect of interfering ob-
`jects on the effective electrical length of an
`antenna of this type.
`Figure 9B shows a method for using a two-
`wire doublet on one half of its normal operat-
`ing frequency. It is recommended that spaced
`open conductor be used both for the radiating
`portion of the folded dipole and for the feed
`line. The reason for this recommendation lies
`in the fact that the two wires of the flat top
`are not at the same potential throughout their
`length when the antenna is operated on one-
`half frequency. Twin-Lead may be used for
`the feed line if operation on the frequency
`where the flat top is one-half wave in length
`. is most common, and operation on one-half fre-
`quency is infrequent. However, if the antenna
`is to be used primarily on one-half frequency
`as shown, it should be fed by means of an
`open-wire line. If it is desired to feed the an-
`tenna with a non-resonant line, a quarter-wave
`stub may be connected to the antenna at the
`points X, X in figure 9B. The stub should be
`tuned and the transmission line connected to
`it in the normal manner.
`
`The antenna system shown in figure 9C may
`be used when not quite enough length is avail-
`able for a full half-wave radiator. The dimen-
`
`LAM Ex1017-p. 11
`LAM V FLAMM
`
`IPRZO15-01767
`
`IGZX/4 AT LOWEST FREQUENCY-T4
` 5" FEEDER
`
`SPREADERS RESONANT OR
`
`NON ‘ RESONANT LINE
`
`335
`__ '
`r-——:--—--— F...._. F*
`
`
`
`G-4“ FEEDER SPREADER5
`
`
`
`zoo n. TWINLE
`
`
`
`
`
`Figure 9
`THREE EFFECTIVE SPACE CONSERVING
`ANTENNAS
`
`The arrangements shown at (A) and (B) are
`satisfactory where resonant feed line can be
`used. However, non-resonant 75-ohm feed
`line may be used in the arrangement at (A)
`when the dimensions in wavelengths are as
`shown.
`In the arrangement shown at (8) low
`standing waves will be obtained on the feed
`line when the overall length of the antenna
`is a half wave. The arrangement shown at
`(C) may be tuned for any reasonable length
`of flat
`top to give a minimum of standing
`waves on the transmission line.
`
`
`
`quarter wavelength can be lengthened elec-
`trically by means of a series loading coil, and
`used as a quarter-wave Marconi. However, if
`the wire is made shorter than approximately
`one-eighth wavelength,
`the radiation resist-
`ance will be quite low. This is a special prob-
`lem in mobile work below about 20-Mc.
`
`22-6
`
`Space-Conserving
`Antennas
`
`In many cases it is desired to undertake a
`considerable amount of operation on the 80- .
`meter or 40-meter band, but sufficient space
`is simply not available for the installation of
`a half-wave radiator for the desired frequency
`of operation. This is a common experience of
`apartment dwellers. The shortened Marconi
`antenna operated against a good ground can
`be used under certain conditions, but the short-
`ened Marconi is notorious for the production
`of broadcast interference, and a good ground
`connection is usually completely unobtainable
`in an apartment house.
`
`LAM Ex 1017-p. 11
`LAM v FLAMM
`IPR2015-01767
`
`

`
`431
`HANDBOOK
`Conserving Antennas
`Space
`
`
`0
`
`'
`FOR DETAIL see FIG. A /
`PHENOLIC BLOCK 2" X I.5'X 0.5
`,
`WRAP CABLES AND BLOCK
`WITH SCOTCH ELECTRICALTAPE /
`SPACE BLOCKS 6’ APART
`ALONG BALUN
`
`
`THE TWO WIRES MAY BE
`FOR DETAIL SEE FIG. A
`SPREAD EITHER HORIZ-
`PHENOLIC BLOCK 2‘X I.5'X 0.5‘
`ONTALLYOR VERTICALLY.
`WRAP CABLES AND BLOCK
`
`WITH SCOTCH ELECI'RICAL TAPE.
`SPACE BLOCKS 6’APART
`
`ALONG BALUN
`
`
`
`
`
`
`
`FIGURE B
`
`REMOVE OUTER JACKET
`FROM A SHORT LENGTH OF
`CABLE AS SHOWN HERE.
`UNBRAID THE SHIELD OF
`COAX C. CUT OFF THE DI-
`ELECTRIC AND INNER CON-
`DUCTOR FLUSH WITH THE
`OUTER JACKET. DO NOT CUT
`THE SHIELD. WRAPSHIELD
`OF COAX C AROUND SHIELD
`OF COAX D. SOLDER THE
`CONNECTION. BEING VERY
`CAREFUL NOT TO DAMAGE
`THE DIELECTRIC MATERIAL.
`HOLD CABLE D STRAIGHT
`WHILE SOLDERING. COVER
`THE AREA WITH A CONTIN-
`UOUS WRAPPING OF SCOTCH
`ELECTRICAL TAPE. NO CON-
`O
`.
`NESEION TO INNER CONDUC-
`
`
`
`_.a|.m.|-|c ——
`
`
`FIGURE A
`CUT OFF SHIELD AND OUTER
`JACKET AS SHOWN. ALLOW
`DIELECTRIC TO EXTEND PART
`WAY TO OTHER CABLE. COVER
`ALL EXPOSED SHIELD AND
`DIELECTRIC ON BOTH CABLES
`WITH A CONTINUOUS WRAP-
`PING OF SCOTCH ELECTRICAL
`TAPE TO EXCLUDE MOISTURE.
`
`
`
`KEEP BALUN AT LEAST B’ CLEAR
`OF GROUND AND OTHER OBJECTS.
`FOR DETAIL SEE FIGURE B
`
`52 OHM RG-B/U, ANY LENGTH
`
`FIGURE B
`
`Remove our:-za JACKET
`mom A SHORT LENGTH or
`CABLE AS snowu HERE.
`uuanmo me SHIELD or
`COAX c curosr ms nu-
`ELECTRIC AND INNER cou-
`DUCTOR FLUSH WITH THE
`OUTER JACKET. DO NOT CUT
`THE SHIELD. WRAPSHIELD
`OF COAX C AROUNDSHIELD
`OF COAX D. SOLDER THE
`CONNECTION. BEING VERY
`CAREFUL NOT TO DAMAGE
`THE DIELECTRIC MATERIAL.
`HOLD CABLE D STRAIGHT
`WHILE SOLDERING. COVER
`THE AREA WITH A CONTIN-
`UOUS WRAPPING OF SCOTCH
`ELECTRICAL TAPE. NO COI-
`NECTION TO INNER CON