Cathodefollower Rf Power Amplifier
Showing the relationships between the tube potentials and currents and the input and output power of the stage. The approximate grid impedance also is given. The design of such an amplifier stage is essentially the same as the design of a grounded-grid amplifier stage as far as the first step is concerned. Then, for the second step the operating conditions given in figure 10 are applied to the data obtained in the first step. As an example, take the 304TL stage previously described. The total...
Antennas and Antenna Matching
Antennas for the lower frequency portion of the h-f spectrum perhaps from 1.8 to 7.0 Mc. , and temporary or limited use antennas for the upper portion of the h-f range, usually are of a relatively simple type in which directivity is not a prime consideration. Also, it often is desirable, in amateur work, that a single antenna system be capable of operation at least on the 3-5-Mc. and 7.0-Mc. range, and preferably on other frequency ranges. Consequently, the first portion of this chapter will be...
Effect Of Fm Modulation Index
Showing the si de-frequency amplitude and distribution for the three most common modulation indices used in FM work. The maximum modulating frequency and maximum deviation are shown In each case. requirements. Some of these methods will be described in the following paragraphs. Reactance-Tube One of the most practical Modulators ways of obtaining direct fre quency modulation is through the use of a reactance-tube modulator. In this arrangement the modulator plate-cathode circuit is connected...
Relation Between Standingwave Ratio And Reflection Coefficient
This chart may be used to convert reflection-coefficient indications such as are obtained with a bridge-type standing-wave indicator or an indicating twin lamp into values of standing-wave ratio. opposite to normal for this test. The resistor R4 is adjusted for full-scale deflection on the 0-100 microammeter. Then the plugs are reversed so that the test signal passes through the instrument in the direction indicated by the arrow on figure 13, and the power level is maintained the same as...
Jrfc
PI-NETWORK ANTENNA COUPLER The pl-network antenna coupler is particularly satisfactory for mobile work since the coupler affords some degree of harmonic reduction, provides a coupling variation to meet varying load conditions caused by frequency changes, and can cancel out reactance presented to the transmitter at the end of the antenna transmission line. For use of the coupler on the 3.9-Mc. bond Cj should have a maximum capacitance of about 250 fi fd., Li should be about 9 ml-crohenrys 30...
Info Nst
Figure 21 COLLINS MECHANICAL FILTERS The Coffins Mechanical Filter is an electro-mechanical bandpass filter which surpasses. In one small unit, the selectivity of conventional, space-consuming filters. At the left is tne miniaturized filter, less than 2V4 fong. Type H is next, and two horizontal mounting types are at right. For exploded view of Collins Mechanical Filter, see figure 46. The frequency characteristics of the mechanical filter are permanent, and no adjustment is required or is...
Wavetrap Circuits
The circuit at A is the most common arrangement, but the circuit at B may give improved results under certain conditions. Manufactured wave traps for the desired band of operation may be purchased or the traps may be assembled from the data given in figure 14. off the air. This is one reason why narrowband FM has become so popular with phone enthusiasts who reside in densely populated Interference Depending upon whether it is Classifications traceable directly to causes within the station or...
Sample Calculation
CONDITION 2 type 611 tubes, Ebb, 1000 input to final stage, 350 w. peak power output needed 350 6 370 w. final amplifier Ebb 2000 v. final amplifier lb .175 a. final amplifier ZL - 2000 - 11400a .175 EXAMPLE chose point on 811 characteristics just to right of Ebb EcC . AJ rXf W .24 IP max. .410 a. EP min. 100 PEAK Po .410 x 1000-100 .410 x 900 369 w. rl 4 x 8600 il Np 78'5 0-1355 76.5 .9 70.5 , wo average with sine wave 184.5w Ib maximum with sine wave 260 ma Wg peak . 100 x 60 8w. driving...
V V 1
SCHEMATIC, GENERAL PURPOSE KILOWATT AMPLIFIER lund HF-100 C, 200 ii ifd., 10KV variable vacuum capacitor. Jennings UCS-200 C3 7500 lififd., variable capacitor. Cardwell 8013 Ci Neutralizing capacitor, disc. Millen 15011 Ci 300 ixiifd., mica, 7250 volt Li-Lto See c oil table, figure 39 PC 47 ohm, 2 watt composition resistor wound with 6 turns 18e. RFC i 2.5 mh. choke. National R-100 RFC2 Heavy duty, wideband r.f. choke. Barker amp Williamson type 800 Si Two pole, 6 position switch. Two Centralab...
The Pierce Crystal Oscillator Circuit
Shown at A is the basic Pierce crystal oscillator circuit. A capacitance of 70 to 75 Hpfd. normally will be required at Cj for optimum operation. If a plate supply voltage higher than indicated is to be used, RFCi may be replaced by a 22,000-ohm 2-watt resistor. Shown at B Is an alternative arrangement with the r-f ground moved to the plate, and with the cathode floating. This alternative circuit has the advantage that the full r-f voltage developed across the crystal may be used as excitation...
Average Plate Characteristics Of Tube 1
fier than when operated as a Class C amplifier. Cqlculation of Calculation of the operating Operating conditions for this type of Characteristics Class B r-f amplifier can be carried out in a manner similar to that described in the previous paragraphs, except that the grid bias voltage is set on the tube before calculation at the value Ecc E ,b V- Since the grid bias is set at cutoff the one-half angle of plate current flow is 90 hence cos 0p is fixed at 0.00. The plate circuit efficiency for a...
Special Vacuum Tube Circuits
A whole new concept of vacuum tube applications has been developed in recent years. No longer are vacuum tubes chained to the field of communication. This chapter is devoted to some of the more common circuits encountered in industrial and military applications of the vacuum tube. The term limiting refers to the removal or suppression by electronic means of the extremities of an electronic signal. Circuits which perform this function are referred to as limiters or clippers. Limiters are useful...
Transmitter Design
The excellence of a transmitter is a function of the design, and is dependent upon the execution of the design and the proper choice of components. This chapter deals with the study of transmitter circuitry and of the basic components that go to make up this circuitry. Modern components are far from faultless. Resistors have inductance and distributed capacity. Capacitors have inductance and resistance, and inductors have resistance and distributed capacity. None of these residual attributes...
Radio Receiver Fundamentals
A conventional reproducing device such as a loudspeaker or a pair of earphones is incapable of receiving directly the intelligence carried by the carrier wave of a radio transmitting station. It is necessary that an additional device, called a radio receiver, be placed between the receiving antenna and the loudspeaker or headphones. Radio receivers vary widely in their complexity and basic design, depending upon the intended application and upon economic factors. A simple radio receiver for...
Info Xsg
Ohm's Law for The simple form of Ohm's Complex Quantities Law used for d-c circuits may be stated in a more general form for application to a-c circuits involving either complex quantities or simple resistive elements. The form is in which, in the general case, , E, and Z are complex vector quantities. In the simple case where the impedance is a pure resistance with an a-c voltage applied, the equation simplifies to the familiar I E R. In any case the applied voltage may be expressed either as...
Effect Of Height On The Radiation Resistance Of A Dipole Suspended Above
and the feed point reactance change more slowly with overall radiator length or with frequency with a fixed length as the conductor diameter is increased, indicating that the effective Q is lowered as the diameter is increased. However, in view of the fact that the damping resistance is nearly all radiation resistance rather than loss resistance, the lower Q does not represent lower efficiency. Therefore, the lower Q is desirable, because it permits use of the radiator over a wider frequency...
Class C Stage 1
BUILDING-OUT THE MODULATION TRANSFORMER This expedient utilizes the leakage reactance of the modulation transformer In conjunction with the capacitors shown to make up a single-section low-pass filter. In order to determine exact values for Cj and C2 plus C3, it is necessary to use a measurement setup such as is shown in figure 23. However, experiment has shown in the case of a number of commercially available modulation transformers that a value for C of 0.002-IJ.fd. and C2 plus C3 of 0.004...
Tuned Rf Vacuum Tube Amplifiers
Tuned r-f voltage amplifiers are used in receivers for the amplification of the incoming r-f signal and for the amplification of intermediate frequency signals after the incoming frequency has been converted to the intermediate frequency by the mixer stage. Signal frequency stages are normally called tuned r-f amplifiers and intermediate-frequency stages are called i-f amplifiers. Both tuned r-f and i-f amplifiers are operated Class A and normally operate at signal levels from a fraction of a...
E E E E
Then the impedance of the parallel combination may be determined from the relation AC Voltage Voltage dividers for use with Dividers alternating current are quite similar to d-c voltage dividers. However, since capacitors and inductors oppose the flow of a-c current as well as resistors, voltage dividers for alternating voltages may take any of the configurations shown in figure 16. Since the impedances within each divider are of the same type, the output voltage is in phase with the input...
Info Vvm
Figure 39 UNITY INDUCTIVE COUPLING Due to the high value of coupling between the two colls, one tuning capacitor tunes both circuits. This arrangement often is useful in coupling from a single-ended to a push-pull stage. INTERSTAGE COUPLING BY MEANS OF A LINK Link interstage coupling is very commonly used since the two stages 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...
Bolt 1
A- 3 8 X 2 CERAMIC INSULATOR, TAPPED AT EACH END FOR 6-32 MACHINE SCREWS, B.C-l 1 8 DIA. BRASS DISC WITH 3 6 CLEARANCE HOLE FOR CERAMIC INSULATOR. LOWER DISC SUPPORTED ON 3 8 CERAMIC INSULATORS. USE FLAT HEAD SCREWS. E- I 1 8 DISC MADE OF TWO LAYERS OF .015 THICK teflon HELD ATOP C BY CELLOPHANE TAPE . F- TWO 6 32 NUTS PLACED UNDER STRAP. STRAP AND NUTS SOLDERED TO BRASS PLATE . HOLE IN PLATE PASSES 6 32 BOLT. Figure 13 CONSTRUCTION OF NEUTRALIZING CAPACITOR FOR 826 STAGE Two capacitors are...
Atomic Structure of Germanium and Silicon
It has been previously stated that the electrons in an element having a large atomic number are grouped into rings, each ring having a definite number of electrons. Atoms in which these rings are completely filled are called inert gases, of which helium and argon are examples. All other elements have one or more incomplete rings of electrons. If the incomplete ring is loosely bound, the electrons may be easily removed, the element is called metallic, and is a conductor of electric current. If...
Simple Magnetron Oscillator
An external tank circuit is used with this type of magnetron oscillator for operation In the lower u-h-f range. In its simplest form the magnetron tube is a filament-type diode with two half-cylindrical plates or anodes situated coaxially with respect to the filament. The construction is illustrated in figure 25A. The anodes of the magnetron are connected to a resonant circuit as illustrated on figure 25B. The tube is surrounded by an electromagnet coil which, in turn, is connected to a...
Typical Doubleconversion Superheterodyne Receivers 1
Illustrated at A is the basic circuit of a commercial double-conversion superheterodyne receiver. At B is illustrated the application of an accessory sharp I-f channel for obtaining improved selectivity from a conventional communications receiver through the use of the double-conversion principle. than half the Gn, of either of the two tubes taken alone. The Cascode The Cascode r-f amplifier, de-Amplifier veloped at the MIT Radiation Laboratory during World War II, is a low noise circuit...
Neutralizing Circuits For Beam Tetrodes
A conventional cross neutralized circuit for use with push-pull beam tetrodes is shown at A . The neutralizing capacitors NC usually consist of small plates or rods mounted alongside the plate elements of the tubes. B and C show grid neutralized circuits for use with a single-ended tetrode stage having either link coupling or capacitive coupling into the grid tank. D shows a method of tuning the screen-tead inductance to accomplish neutralization in a single-frequency v-h-f tetrode amplifier,...
Info Qnt
6. By substituting the loaded grid resistance figure in the formula in the first paragraph, the grid driving power is now found to be approximately 2.3 watts. Screen Circuit By reference to the plate Considerations characteristic curve of the 813 tube, it can be seen that at a minimum plate potential of 500 volts, arid a maximum plate current of 0.6 ampere, the screen current will be approximately 30 milli-amperes, dropping to one or two milliamperes in the quiescent state. It is necessary to...
Info Bym
POSITIVE-GRID CHARACTERISTICS lp VS. Eg OF A TYPICAL TRIODE Plate characteristics of this type are most commonly used In determining the pulse-signal operating characteristics of a trlode amplifier stage. Note the large emission capability of the oxide-coated heater cathode in tubes of the general type of the 6J5. The transconductance is also numerically equal to the amplification factor divided by the plate resistance. Gm i Rp. Transconductance is most commonly expressed in...
Lefthand View Of Kilowatt Amplifier Of Figure
Above shielded meter box is the protective micro-switch which opens the primary power circuit when the panel door is not closed. Tube sockets are recessed in the chassis so that top of tube socket shells are about ' -inc i above chassis level. On right side of amplifier facing it from the rear the tube socket is nearest the panel, with the neutralizing capacitor behind it. On the opposite side, the capacitor is nearest the panel with the tube directly behind it. This layout transposition...
Edition
Editors and Engineers, Ltd. Summerland, California, U.S.A. Copyright under Pan-American Convention AH Translation Rights Reserved The Radio Handbook in Spanish or Italian is available from us at 8.25 postpaid. French and Dutch editions in preparation. Outside North America, if more convenient, write Spanish Marcombo, S.A., Av. Jose Antonio, 584, Barcelona, Spain Italian Edizione C.E.L.I., Via Gandino 1, Bologna, Italy French or Dutch P. H. Brans, Ltd., 28 Prins Leopold St., Borgerhout, Other...
Crystal 1
Figure 19 VARIABLE SELECTIVITY CRYSTAL FILTER This circuit permits of a greater control of selectivity than does the circuit of figure 16, and does not require a split-stator variable capacitor. Figure 19 VARIABLE SELECTIVITY CRYSTAL FILTER This circuit permits of a greater control of selectivity than does the circuit of figure 16, and does not require a split-stator variable capacitor. As the output circuit is detuned from resonance, its impedance is lowered, and the selectivity increases....
Inexpensive Watt Modulator Using Tubes
Ti Poly-pedance Class B driver transformer 2 1 ratio. Stancor A-4761 Ts 500 watt output transformer. 18K primary, 6.2SK secondary. Chicago CMS-3 T, 70 volts, 10 amperes. Stancor C-6467 M 0 - 500 ma. Class B zero bias operation of tetrode tubes is made possible by the application of the driving signal to the two grids of the tubes as shown in figure 19. Tubes such as the 6AQ5, 6L6, 807, 803, and 813 work well in this circuit and neither a screen supply nor a bias supply is required. The drive...
Projection Drawing Showing The Resultant Lissajous Pattern When A Sine Wave
wave. Any recurrent waveform plotted against time can be displayed and analyzed by the same procedure as used in these examples. The sine wave problem just illustrated is typical of the method by which any waveform can be displayed on the screen of the cathode-ray tube. Such waveforms as square wave, sawtooth wave, and many more irregular recurrent waveforms can be observed by the same method explained in the preceding paragraphs. Another fundamental pattern is the Lissajous figure, named after...
Link Coupled Output Circuits For Pushpull Amplifiers 1
be employed as the exciter. Tetrode tubes such as the 4-250A require only 10 to 15 watts of actual drive from the exciter for proper operation of the amplifier stage at 1-kilowatt input. This means that the output from the 100-watt transmitter has to be cut down to the 15 watt driving level. This is a nuisance, as it requires the addition of swamping resistors to the output circuit of the transmitter-exciter. The triode tubes, therefore, would lend themselves to a much more convenient driving...
Simple Fm Reactancetube Modulator
mounted in close proximity to the v.f.o. so that the lead from the 6CL6 to the grid circuit of the oscillator can be as short as possible. A practical solution is to mount the reactance modulator in a small box on the side of the y-f-o cabinet. By incorporating speech clipping in the reactance modulator unit, a much more effective use is made of a given amount of deviation. When the FM signal is received on an AM receiver by means of slope detection, the use of speech clipping will be noticed...
Ntensity Mod 1
the cathode-ray tube. Also, as shown in figure 1, S2 has been incorporated to by-pass the vertical amplifier and capacitively couple the input signal directly to the vertical deflection plate if so desired. In figure 2, V, is a 6AC7 pentode tube which is used as the vertical amplifier. As the signal variations appear on the grid of V variations in the plate current of V, will take place. Thus signal variations will appear in opposite phase and greatly amplified across the plate resistor, R7....
Underchassis View Of Power Amplifier
All power wiring beneath the chassis is placed within braid to reduce pickup of r.f. energy. Note that shield divides area into two sections. Smaller area contains output capacitor of pi-network, 6ALS diode voltmeter and high voltage leads. Larger area contains grid circuit components and meter switch. Sensitive relay RYs is mounted to wall of the chassis behind the grid tuning capacitor. Three .001, 5 Kv. ceramic screen bypass capacitors are mounted close to socket terminals. Grid turret...
Singlestage Screen Grid Keyer For Tetrode Tubes 1
tetrode is keyed by this method, there is the possibility of a considerable backwave caused by r-f leakage through the grid-plate capacity of the tube. Certain hi- i triode tubes, such as the 811-A and the 805, automatically block themselves when the grid return circuit is opened. It is merely necessary to insert a key and associated key click filter in the grid return lead of these tubes. No blocking bias supply is needed. This circuit is shown in figure 12. A more elaborate blocked-grid...
Kilowatt Dummy Load Schematic 1
obtain the approximate value of the impedance directly from the scale of the meter. If the component is a capacitor, the value of impedance may be taken as its reactance at the measurement frequency and the capacitance determined accordingly. But the d-c resistance of an inductor must also be taken into consideration in determining its inductance. After the d-c resistance and the impedance have been determined, the reactance may be determined from the formula Xl VZ R2. Then the inductance may...
Two Colinear Halfwave Antennas In Phase Produce A Db Gain When Separated
the terminal radiation resistance in ohms at any current loop is approximately 100 times the number of elements. It should be borne in mind that the gain from a colinear antenna depends upon the sharpness of the horizontal directivity since no vertical directivity is provided. An array with several colinear elements will give considerable gain, but will have a sharp horizontal radiation pattern. Double Extended The gain of a conventional Zepp two-element Franklin colin ear antenna can be...
Rhombic Antenna Gain
Showing the theoretical gain of a rhombic antenna, in terms of the side length, over a half-wave antenna mounted at the same height above the same type of soil. 0 1 2 3 4 5 7 8 9 10 It 12 13 14 13 16 17 18 19 20 1 LENGTH OF EACH LEG OF RHOMBIC IN WAVELENGTHS RADIATION PATTERNS OF A PAIR OF DIPOLES OPERATING WITH IN-PHASE EXCITATION, AND WITH EXCITATION 180 OUT OF PHASE If the dipoles are oriented horizontally most of the directivity will be in the vertical plane if they are oriented vertically...
Figure PENTAGRID MIXER CIRCUIT FOR SSB FREQUENCY CONVERSION
quency into the 3 grid. This is the reverse of the usual grid connections, but it offers about 10 db improvement in distortion. The plate circuit is tuned to select the desired output frequency product. Actually, the output of the mixer tube contains all harmonics of the two input signals and all possible combinations of the sum and difference frequencies of all the harmonics. In order to avoid distortion of the SSB signal, it is fed to the mixer at a low level, such as 0.1 to 0.2 volts. The...
Transition Oscillator
C, 0.01- ifd. mica for r.f. 10- fd. elect, for a.f. Cj 0.00005- A fd. mica for r.f. 0.1- ifd. paper for a.f. C3 0.003- fifd. mica for r.f. 0.5- fJ-ld. paper for a.f. C, 0.01-jUfd. mica for r.f. 8- fd. elect, far a.f. CATHODE-COUPLED OSCILLATOR Q 0.00005- fd. mica for r.f. 0.1-flfd. paper for audio Cj 0.003- Afd. mica for r.f. 8-p.fd. elect, for audio Rt 47K Vi-watt carbon R, IK 1 -watt carbon as the frequency determining tank circuit, and is classed as a two terminal oscillator. In fact, the...
Schematic Of Beam Power Tube Modulator 1
Ti Driver transformer. Stancor A-4701, or UTC S-10. Tz Poly-pcdance Modulation transformer 60-watt level Stancor A-3S93, or UTC S-20 125-watt level Stancor 4-3894 output tubes, and a plate current milliammeter. The power supply has not been included. The 6SJ7 pentode first stage is coupled through the volume control to the grid of a 6J5 phase inverter. The output of the phase inverter is capacitively coupled to the grids of a 6SN7-GT which acts as a push-pull driver for the output tubes....
Standard Circuit For Resistancecapacitance Coupled Pentode Amplifier Stage
assist the designer of such stages, data on operating conditions for commonly used tubes is published in the RCA Tube Handbook RC-16. It is assumed, in the case of the gain equations of figure 5, that the cathode by-pass capacitor, Ck, has a reactance that is low with respect to the cathode resistor at the lowest frequency to be passed by the amplifier stage. R-C Coupled Figure 6 illustrates the Stand-Pentode Stages ard circuit for a resistance-capacitance coupled pentode amplifier stage....
Class B Plate Modulation
This type of modulation Is the most flexible in that the loading adjustment can be made In a short period of time and without elaborate test equipment after o change In operating frequency of the Class C amplifier has been made. power output capability of one-half the input to the Class C stage. If the modulator is a Class B audio amplifier, the average power required of it may vary from one-quarter to more than one-half the Class C input depending upon the waveform. However, the peak power...
Diagrammatic Representation Of The Doherty Linear 1
desirable phase shift of 90 between the plate circuits of the carrier and peak tubes, an equal and opposite phase shift must be introduced in the exciting voltage to the grid circuits of the two tubes so that the resultant output in the plate circuit will be in phase. This additional phase shift has been indicated in figure 12 and a method of obtaining it has been shown in figure 13- Comparison Between The difference between Linear and the Doherty linear m- Grid Modulator plifier and the...
To Smooth Or Trim The Edges Of Reynolds Doityourself Aluminum Stock
INEXPENSIVE OPERATING DESK MADE FROM ALUMINUM ANGLE STOCK, PLYWOOD AND A FLUSH-TYPE DOOR INEXPENSIVE OPERATING DESK MADE FROM ALUMINUM ANGLE STOCK, PLYWOOD AND A FLUSH-TYPE DOOR projecting through corresponding holes in the panel. Working with The necessity of employing Aluminum electrically tight enclosures for the containment of TVI-producing harmonics has led to the general use of aluminum for chassis, panel, and enclosure construction. If the proper type of aluminum material is used, it may...
Radiation Resistance As A Function Of Element Spacing For A Twoelement
Such an antenna is capable of a signal gain of 5 db over a dipole, with a front-to-back ratio of 7 db to 15 db, depending upon the adjustment of the parasitic element. The parasitic element may be used either as a director or as a reflector. The optimum spacing for a reflector in a two-element array is approximately 0.13 wavelength and with optimum adjustment of the length of the reflector a gain of approximately 5 db will be obtained, with a feed-point resistance of about 25 ohms. If the...
High Power Pushpull Amplifier Uses A Tubes 1
This amplifier design is typical of push-pull stages regardless of power level. Tubes are visible through screened openings in panel. Controls are top to bottom Output link tuning, variable link coupling, plate circuit tuning, and grid circuit tuning. Amplifier is housed in special 21 rack. Filament meters for each tube are on auxiliary panel holding bias and screen supply. SCHEMATIC, PUSH-PULL HIGH POWER AMPLIFIER Ci 700 - 100 ii ifd. butter-fly capacitor. Barker amp Williamson type JCX Cr, Cj...
MiJM
Relays are shown in unenergized position. stage, which is plate modulated by the 12AQ5 audio amplifier. The r-f amplifier is bridge neutralized by capacitor Go for greatest stability at the operating frequency range. The plate circuit of the 5763 is pi-coupled to a 52- or 72-ohm external load. Transfer from reception to transmission is accomplished by means of two d-c relays actuated by a push-to-talk switch in the microphone. The six volt relay coils are connected in series for twelve volt...