Transistors Can Replace Vibrator In Mobile Power Supply System

B Vibrator can be represented by two single-pole single throw switches, or transistors. C Push-Pull square wave oscillator is driven by special feedback windings on power transformer. D Addition of bias in base-emitter circuit results in oscillator capable of starting under full load. plication of a minute exciting signal. When the transistor is nonconductive it may be considered to be an open circuit. When it is in a conductive state, the internal resistance is very low. Two transistors...

Tuning Methods For Cylindrical Resonant Cavities

Dimpled sphere, sphere with reentrant cones of various sorts, cylinder, prism (including cube), ellipsoid, ellipsoid-hyperboloid, dough-nut-shape, and various reentrant types. In appearance, they resemble in their simpler forms metal boxes or cans. The cavity actually is a linear circuit, but one which is superior to a conventional coaxial resonator in the s-h-f range. The cavity resonates in much the same manner as does a barrel or a closed room with reflecting walls. Because electromagnetic...

Vacuum Tube Principles

In the previous chapters we have seen the manner in which an electric current flows through a metallic conductor as a result of an electron drift. This drift, which takes place when there is a difference in potential between the ends of the metallic conductor, is in addition to the normal random electron motion between the molecules of the conductor. The electron may be considered as a minute negatively charged particle, having a mass of 9 X 10 28 gram, and a charge of 1.59 X 10 19 coulomb....

Rf Input

XL ABOUT 1500 1 AT fo XC ABOUT 750 iL AT fo Figure 13 CATHODE-FOLLOWER PHASE MODULATOR The phase modulator illustrated above Is quite satisfactory when the stage is to be operated on a single frequency or over a narrow range of frequencies. XL ABOUT 1500 1 AT fo XC ABOUT 750 iL AT fo A conventional communications receiver may be used to receive narrow-band FM transmissions, although performance will be much poorer than can be obtained with an NBFM receiver or adapter. However, a receiver...

Horizontal Antennas In Free Space

Use a directive antenna than to increase transmitter power, if more than a few watts of power is being used. Directive antennas for the high-frequency range have been designed and used commercially with gains as high as 23 db over a simple dipole radiator. Gains as high as 35 db are common in direct-ray microwave communication and radar systems. A gain of 23 db represents a power gain of 200 times and a gain of 35 db represents a power gain of almost 3500 times. However, an antenna with a gain...

Qvt

Figure 14 l-F AMPLIFIER COUPLING ARRANGEMENTS The Interstage coupling arrangements illustrated above give a better shape factor (more straight sided selectivity curve) than would the same number of tuned circuits coupled by means of tubes. Figure 14 l-F AMPLIFIER COUPLING ARRANGEMENTS The Interstage coupling arrangements illustrated above give a better shape factor (more straight sided selectivity curve) than would the same number of tuned circuits coupled by means of tubes. width in a good...

Lines

21-1 Radiation from an Antenna 403 21-2 General Characteristics of Antennas 404 21-3 Radiation Resistance and Feed-Point Impedance 407 21-6 Propagation of Radio Waves 413 21-7 Ground-Wave Communication 414 21-8 Ionospheric Propagation 21-10 Non-Resonant Transmission Lines 421 21-11 Tuned or Resonant Lines 424 21-12 Line Discontinuities 425 Chapter Twenty-Two. ANTENNAS AND ANTENNA MATCHING 426 22-1 End-Fed Half-Wave Horizontal Antennas 426 22-2 Center-Fed Half-Wave Horizontal Antennas 427 22-3...

Chapter

The field of radio is a division of the much larger field of electronics. Radio itself is such a broad study that it is still further broken down into a number of smaller fields of which only shortwave or high-frequency radio is covered in this book. Specifically the field of communication on frequencies from 1.8 to 450 megacycles is taken as the subject matter for this work. The largest group of persons interested in the subject of high-frequency communication is the more than 150,000 radio...

Monitoring Circuit For Modulated Wave Pattern

The internal sweep circuit of the oscilloscope is applied to the horizontal plates, and the modulated r-f signal is applied to the vertical plates, as described before. If desired, the internal sweep circuit may be sny-chronized with the modulating signal of the transmitter by applying a small portion of the modulator output signal to the external sync post of the oscilloscope. The percentage of modulation may be determined in the same fashion as with a trapezoidal pattern. Figures...

Coefficient

The crystal blank is then rough-ground almost to frequency, the frequency increasing in inverse ratio to the oscillating dimension (usually the thickness). It is then finished to exact frequency either by careful lapping, by etching, or plating. The latter process consists of finishing it to a frequency slightly higher than that desired and then silver plating the electrodes right on the crystal, the frequency decreasing as the deposit of silver is increased. If the crystal is not etched, it...

Highlevel Splatter Suppressor

The high-vacuum diode acts as a series lim-iter to suppress negative-peak clipping in the modulated r-f amplifier as a result of large amplitude negative-peak modulating signals. In addition, the low-pass filter following the diode suppresses the transients which result from the peak-clipping action of the diode. Further, the filter attenuates all harmonics generated within the modulator system whose frequency lies above the cutoff frequency of the filter. The use of an appropriate value of...

Simple Silicon Crystal Noise Generator

The source of excitation is now the resonant frequency of the load, and the radiation resistance of the load may be read upon the dial of the Antennascope. On measurements on 80 and 40 meters, it might be found that it is impossible to obtain a complete null on the Antennascope. This is usually caused by pickup of a nearby broadcast station, the rectified signal of the broadcast station obscuring the null indication on the Antennascope. This action is only noticed when antennas of large size...

Schematic Of Mechanical Filter Adapter

Ct, Ci 600 iiifd. ceramic (270- and 330 fi ifd. in parallel) Ci, Ci 720 iiifd. ceramic C5, Ce 10 ii ifd. tubular ceramic (Aerovox Cl-l) FL 455 kc. mechanical filter (3.1 kc. bandwidth) (Collins 4SSJ-31) Li, Ls 200 microhenry slug-tuned loop stick coil (Superex VLt or J. W. Miller 6300) Pi Male octal plug with retaining ring (Amphenol B6-PM8) Ri 18K, 10 watt. Place between pins 4 and 8 of PI socket for plate supply greater than 130 volts. Use jumper for 130 volts or less (see text). Ri is screen...

Schematic Of Transistor Broadcast Receiver

RCA VS-300 C, 365 fifitd. Lafayette Radio Co. MS-214, or Allied Radio Co. 6IN-009 L Transistor Loopstick coll. Lafayette Radio Co. MS-166 LS 3 loudspeaker, 12-ohm voice coil. Lafayette Radio Co. SK-39 Ti 500 ohm pri., 12 ohm sec. Transistor transformer. Thordarson TR-18 of building and operating their own receiving and transmitting equipment. The Transceiver A popular item of equipment on five meters during the late thirties, the transceiver is making a comeback...

Standby

SCHEMATIC, EXCITER DECK OF ALL-BAND TRANSMITTER C 300 y ifd. Bud CE-2008 dual bearing capacitor Ci 300 jijifd. silver mica capacitor. Vary for desired frequency coverage. Cj 2000 uiifd. High accuracy capacitor, tolerance 1 , temperature coefficient zero, plus or minus 10 p.p.m. Centralab 950-202 Ci, C , Cs 25 iitifd. midget variable padding capacitor, ceramic Li 19 turns 20 e. wire, tapped 5 turns from ground end. Wound on ceramic form, W diam., 1 high. Space the winding by interwinding 28 e....

YHF and UHF Antennas

The very-high-frequency or v-h-f frequency range is defined as that range falling between 30 and 300 Mc. The ultra-high-frequency or u-h-f range is defined as falling between 300 and 3000 Mc. This chapter will be devoted to the design and construction of antenna systems for operation on the amateur 50-Mc., 144-Mc., 235-Mc., and 420-Mc. bands. Although the basic principles of antenna operation are the same for all frequencies, the shorter physical length of a wave in this frequency range and the...

Block Diagram Of Ten Meter Transceiver

Series padding in the r-f and mixer circuits is employed for good tracking across the band. An i-f channel of 1.5 Mc. is used in this unit. This particular frequency was chosen to eliminate the troublesome image problem, so prevalent on the 10 meter band when the usual 455 kc. i-f channel is employed. Selectivity suffers a bit when the higher frequency channel is used, but a total of eight tuned circuits (four transformers) provide an acceptable passband for...

R Volume

NOTES 1 - CAPACITORS MARKED C ARE -01 CERAMIC DISC, 600 V. 2 - ALL RESISTORS WATT UNLESS OTHERWISE NOTED. Figure 38A SCHEMATIC, 10 METER TRANSCEIVER C .07 fifd., 600 volt ceramic capacitor. Centralab DD6-103 RFC 2J 2 mh. Millen miniaturized J300-2500 CiA-B-C 75 M ifd. per section. All Star Products Co., Defiance, Ohio, Type C3 SiA-B-C-D-C-F 6 pole, two position switch. Centralab PA-2019 C, 75 i ifd. Bud MC-565 SRi, SRt 750 mo. selenium rectifier. Federal 1005 C, 30 liiifd. Bud LC-7657 Ti-Ti,...

Schematic Of The Singlesection Halfwave Filter

The constants given below are for a characteristic Impedance of 52 ohms, for use with RG-8 U and RG-58 U cable. Coil L should be checked for resonance at the operating frequency with Cj, and the same with L2 and C4. This check can be made by soldering a low-inductance grounding strap to the lead between Lj and L2 where It passes through the shield. When the colls have been trimmed to resonance with a grid-dip meter, the grounding strap should of course be removed. This filter type will give an...

Differential Keying System With Oscillator Switching Diode

DIFFERENTIAL KEYER EMPLOYED IN JOHNSON TRANSMITTERS conducting and t'len continue operating until alter V2 and V3 have stopped conducting. Potentiometer R1 adjusts the hold time for VFO operation after the key is opened. This may be adjusted to cut off the VFO between marks of keyed characters, thus allowing rapid break-in operation.

Ecclesjordan Multivibrator Circuits

Oscillation is maintained by the process of building up and discharging the store of energy in the grid coupling capacitors of the two tubes. The charging and discharging paths are shown in figure 7. Various forms of multivibrators are shown in figure 8. The output of a multivibrator may be used as a source of square waves, as an electronic switch, or as a means of obtaining frequency division. Submultiple frequencies as low as one-tenth of the injected synchronizing...

Czc Cd

C2A,B.C,D EACH SECTION 20 JJF. 450 V. C7 2430 JUJUFD (.002 JUFD MICA 5 WITH C8 4660 iliJFD. C.0043UFD MICA 5lb WITH C9 1215 UiJFD. (.001 jUFO MICA 5 WITH C10 607.5DUFD (500UJUFD MICA 5 WITH C18-350JUUFD 600 V. MICA 10 (250JUJJFD R7,R10 133,300 OHMS, 1 2 WATT 1 9b R8,R9 100,000 OHMS, 1 2 WATT 19b T1 STANCOP A-53C TRANSFORMER . T2,T3 UTC R-38A TRANSFORMER. Si DPDT TOGGLE SWITCH ELECTROLYTIC Gl, 2,3,4 1N52 GERMANIUM DIODE OR EQUIVALENT 170-760 UUFD TRIMMER) Li, l_2 33 T. N 21 E. WIRE CLOSE WOUND...

View Of Walkietalkie Showing Major Components

Chassis of transceiver is specially bent to fit com-ponents in smallest possible space. Oscillator coll Lt is at left separated from triplet coil Ls by small shield. Output coil Ls is to rear. 5676 detector tube is at right rear, flanked by 20 tifd. filter capacitor. Audio tubes are under chassis partition at right. Quench filter capacitors are to right of coil Ls. These adjustments may be done quickly and easily with the aid of a grid dip oscillator. After the r-f circuits are adjusted the...

View Of Transistorized Ssb Exciter

The audio and r-f networks are mounted on a phenolic sheet attached to the bottom of the chassis. The I2BYTA linear amplifier and shield are mounted on a small aluminum bracket at the left of the assembly. Grid coil L3 is beside the tube, and plate coil Lt is behind the tube. Coil Li is to the right of Ls with sideband switch St behind it. The two r-f balancing controls Ri and Rt are at the extreme right of the chassis panel. to reduce the 12-6 volt primary supply to 9 volts for the 2N170...

Lowpass Filter Schematic Diagrams

The filter illustrated at (A) uses m-derived terminating half sections at each end, with three constant-k mid-sections. The filter at (B) is essentially the same except that the center sect on has been changed to act as an m-derived section which can be designed to offer maximum attenuation to channels 2, 4, 5, or 6 in accordance with the constants given below. Cutoff frequency is 45 Mc. in all cases. All coils, except L4 in (B) above, are wound V2 i.d. with 8 turns per inch. Cl Cs 41.5W*fd....

Operational Circuit For Ssb Exciter Using The Burnell Kc Sideband Filter

Component in the whole system the first sideband filter. It is the function of this first sideband filter to separate the desired 47 to 50 kc. sideband from the unneeded and undesired 50 to 53 kc. sideband. Hence this filter must have low attenuation in the region between 47 and 50 kc., a very rapid slope in the vicinity of 50 kc., and a very high attenuation to the sideband components falling between 50 and 53 kilocycles. Burnell & Co., Inc., of Yonkers, New York produce such a filter,...

Coil Table For And Meter Transceiver

L1 - 6t. 20 e.t 3 8 dia., 1 2 long. tap 2 1 2 t. from ground eno. l2-12t. t* 20 e, 3 16 dia, 7 16* long. mount between pi n 3 and pin 6 of socket v1. l3, l4- 5 t. 16 e. 1 4 dia., spaced wire dia. on CTC iron core form PLSS. center-to-center distance between l3 and l4 is 3 4. ls- PLATE WINDING6 t. 16 e, 5 16 dl a. 1 2 long. GRID WINDING 1 t. plastic hookup wire between two cold end turns of plate winding. l6- 10 t. 20 e, 3 8 dia., 1 2 long. tap 4t. from gnd. end l7, l8- 16t.tt 20 e. close wound...

Common Types Of Selfexcited Oscillators

Fixed capacitor values are typical, but will vary somewhat with the application. In the Clapp oscillator circuits (G) and (H), capacitors Cj and C2 should have a reactance of 50 to 700 ohms at the operating frequency of the oscillator. Tuning of these two oscillators is accomplished by capacitor C. In the circuits of (E), (F), and (H), tuning of the tank circuit in the plate of the oscillator tube will have relatively small effect on the frequency of oscillation. The plate tank circuit also...

Various Diode Limiting Circuits

Series diodes limiting positive and negative peaks are shown in A and B. Parallel diodes limiting positive and negative peaks are shown in C and D. Parallel diodes limiting above and befow ground are shown in E and F. Parallel diode limiters which pass negative and positive peaks ping will occur is set by R which controls the positive potential applied to the diode plates. Under static conditions, a d-c voltage is obtained from R4 and applied through R3 to both plates of the 6AL5 tube. Current...

Slideback Vt Voltmeter

By connecting a variable source of voltage in series with the input to a conventional v-t voltmeter, or in series with the simple triode voltmeter shown above, a slide-back a-c voltmeter tor peak voltage measurement con be constructed. Resistor R should be about 1000 ohms per volt used at battery B. This type of v-t voltmeter has the advantage that it can give a reading of the actual peak voltage of the wave being measured, without any current drain from the source of voltage. instrument having...

Plate And Grid Parasitic Suppression In Tetrode Tubes

Therefore it is always wise to follow a definite procedure in checking a new transmitter for parasitic oscillations. Parasitic oscillations of all types are most easily found when the stage in question is running by itself, with full plate (and screen) voltage, sufficient protective bias to limit the plate current to a safe value, and no excitation. One stage should be tested at a time, and the complete transmitter should never be put on the air until all stages have been thoroughly...

Ma

Cation in the amateur station for such a supply is for items of test equipment such as the type LM and BC-221 frequency meters, for frequency converters to be used in conjunction with the station receiver, and for auxiliary equipment such as high selectivity i-f strips or variable frequency oscillators. Equipments such as these may be operated from a supply delivering 250 to 300 volts at up to 50 milli-amperes of plate current. A filament source of 6.3 or 12 volts may also be required, as will...

Info

Note that one number often fails to divide into another evenly. Hence there is often a quantity left over called the remainder. The rules for placing the decimal point are the reverse of those for multiplication. The number of decimal places in the quotient is equal to the difference between the number of decimal places in the dividend and that in the divisor. It is often simpler and clearer to remove the decimal point entirely from the divisor by multiplying both dividend and divisor by the...

Alternating Current And Direct Current

Graphical comparison between unldrectional (direct) current and alternating current as plotted against time. (1) the kilocycle (abbr., kc.), 1000 c.p.s. (2) the Megacycle (abbr., Mc.), 1,000,000 c.p.s. or 1000 kc. (3) the kilo-Megacycle (abbr., kMc.), 1,000,000,000 c.p.s. or 1000 Mc. With easily handled units such as these we can classify the entire usable frequency range into frequency bands. The frequencies falling between about 15 and 20,000 c.p.s. are called audio frequencies, abbreviated...

Transformer or filament winding Note also that

The operating plate-to-cathode voltage on the 6L6 modulator tube does not exceed the 360-volt rating of the tube, since the operating potential of the cathode is considerably above ground potential. Suppressor-Grid Still another form of effi-Modulation ciency modulation may be obtained by applying the audio modulating signal to the suppressor grid of a pentode Class C r-f amplifier. Basically, suppressor-grid modulation operates in the same general manner as other forms of efficiency modulation...

Which will accomplish full modulation With

Correct adjustments of the operating conditions of the stage it can be made to clip positive and negative modulation peaks symmetrically. However, the inherent peak clipping ability of the stage should not be relied upon as a means of obtaining a large amount of speech compression, since excessive audio distortion and excessive screen current on the modulated stage will result. Characteristics of a An important character-Typical Screen- istic of the screen-modu- Modulated Stage lated stage,...

M

Magnetic Air gap Circuit field flux 35 eddy current hysteresis loss induction left hand rule Permeability reluctance saturation 36 Magnetism residual 35, 37 Magnetomotive force (M. M. F.) 36 Magnetron Magnitude, scalar Majority carrier 93 Marconi antenna 408, 432, 434, 438 Mast, A-frame Matching stub, antenna 445, 503 Matching systems antenna 442 Matching transformer Mathematics, radio Maximum usable frequency 13, 417 Maxwell, def. of M-derived filter Measurements Antenna 730 Bridge Circuit...

Push Pull Triode Amplifiers

Figure 2 shows a basic push-pull triode amplifier circuit. While variations in the method of applying plate and filament voltages and bias are sometimes found, the basic circuit remains the same in all amplifiers. Filament Supply The amplifier filament transformer should be placed right on the amplifier chassis in close proximity to the tubes. Short filament leads are necessary to prevent excessive voltage drop in the connecting leads, and also to prevent r-f pickup in the filament circuit....

Swr Curve Of Meter Broadband Dipole

See fig. 12 for connection 52ohm coaxial line ohms. The ground losses are now reduced by a factor of 4. In addition, the antenna may be directly fed from a 50-ohm coaxial line, or directly from the unbalanced output of a pi- network transmitter. Since a certain amount of power may still be lost in the ground connection, it is still of greatest importance that a good, low resistance ground be used with this antenna. The Collins Shown in figures 11 and 12 Brood-band are broad-band dipoles for...

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

Shift Modulator Tube Photo

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...

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...

Parristic Choke

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

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...

Effect Of Height On The Radiation Resistance Of A Dipole Suspended Above Perfect Ground

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

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...

Bolt

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

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,...

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

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

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 Applied To The Horizontal Axis Is Three

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

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

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

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

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 Onehalf Wavelength

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

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

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

Making The Modulation Transformer

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

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 Parasitic Array

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

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...

Watt Vhf Transmitter

Small 7 75-vo t blower motors for 826 tubes are in upper left corner of chassis. Buffer plate line LsA-B occupies left-hand portion of chassis. All leads are kept clear of this area. Under-chassis power leads are run in shielded braid to reduce r-f pick-up. An L-shaped shield partition isolates frequency doubter stages from buffer plate line. Capacitors Cs and Cs are ganged, as are capacitors Cn and Cj. Power supply components occupy lower right-hand corner of chassis. The top of the 9903 -5894...

Figure Schematic Ssb Jr

Having a push-pull output circuit tuned to the r-f carrier frequency. The modulator drives a linear amplifier directly at the output frequency. The complete circuit of the exciter is shown in figure 36. The first tube, a 12AU7, is a twin-triode serving as a speech amplifier and a crystal oscillator. The second tube is a 12AT7, acting as a twin channel audio amplifier following the phase-shift audio network. The linear amplifier stage is a 6AG7, capable of a peak power output of 5 watts....

Zero Bias Tetrode Modulator Eliminates Screen And Bias Supplies

Low driving power and simplicity are key features of this novel modulator. Tubes ranging in size from 6AQS's to 813's may be employed in this circuit. Vi, V, 6AQS, 6L6, 807, 803, 813, etc. eg-g rms 70 volts driving power 7-8 watts resting plate CUR. 50 ma. max. plate cur . 340 ma . power output 510 wa tts suppressor volt. - 230-340 v. eg-g rms 70 volts driving power 7-8 watts resting plate CUR. 50 ma. max. plate cur . 340 ma . power output 510 wa tts suppressor volt. - 230-340 v.

Showing The Effect Of Cathode Lead Inductance

The degenerative act on of cathode lead inductance tends to reduce the effective grid-to-cathode voltage with respect to the voltage available across the input tuned circuit. Cathode lead inductance also introduces undesirable coupling between the input and the out-put circuits. low, the local oscillator must furnish considerable power to the diode mixer. A good diode mixer has an overall gain of about 0.5. The Triode Mixer A triode mixer has better gain and a better noise figure than the diode...

Double Sideband Output From Balanced Modulator With Sinewave Modulation

Figure 42 DOUBLE-SIDEBAND SUPPRESSED-CARRIER SIGNAL The envelope shown at B also is obtained on the oscilloscope when two audio frequencies of the same amplitude are fed to the input of a single-sideband transmitter. transformer is placed between the mixer stage and the 6AG7 output stage. A maximum signal of 3 watts may be obtained from the 6AG7 linear amplifier. Selection of the upper or lower sideband is accomplished by tuning the 6U8 beating oscillator across the passband of the mechanical...

Reactancefrequency Chart For Rf

This chart is used in conjunction with the nomograph on page 569 for radio frequency tank coil computations. Figure 42. THE SIMPLEST FORM OF NOMOGRAM. Figure 42. THE SIMPLEST FORM OF NOMOGRAM. plest form, it is somewhat like the lines in Figure 42. If the lines a, b, and c are parallel and equidistant, we know from ordinary geometry, that b i 2 a c . Therefore, if we draw a scale of the same units on all three lines, starting with zero at the bottom, we know that by laying a straight-edge...

T

TYPICAL FREQUENCY-CONVERTER MIXER STAGES The relative advantages of the different circuits are discussed in the text that both these circuits use control-grid injection of both the incoming signal and the local-oscillator voltage. Hence, paradoxically, circuits such as these should be preceded by an r-f stage if local-oscillator radiation is to be held to any reasonable value of field intensity. Diode Mixers As the frequency of operation of a superheterodyne receiver is increased above a few...

Superregenerative Detector Circuit

A self-quenched superregenerative detector such as illustrated above is capable of giving good sensitivity in the v-h-f range. However, the circuit has the disadvantage that its selectivity is relatively poor. Also, such a circuit should be preceded by an r-f stage to suppress the radiation of a signal by the oscillating detector. The optimum quenching frequency is a function of the signal frequency. As the operating frequency goes up, so does the optimum quenching frequency. When the quench...

L and Pi Matching Networks

The L and pi networks often can be put to advantageous use in accomplishing an impedance match between two differing impedances. Common applications are the matching between a transmission line and an antenna, or between the plate circuit of a single-ended amplifier stage and an antenna transmission line. Such networks may be used to accomplish a match n - Xl _ Xc . Rp _ Rp Ra Ra Xc Xl Xl Xc n - Xl _ Xc . Rp _ Rp Ra Ra Xc Xl Xl Xc Figure 27 THE L NETWORK IMPEDANCE TRANSFORMER The L network is...

Block Diagram Of Vhf Transmitter

Tube Transmitter Circuits

A General transmitter circuit, showing operating frequencies of the various stages, Vi is a plug-in frequency multiplier. B Quarter-wave tank circuit is employed in amplifier plate configuration at 144 Mc. Shorting bar is removed for SO Mc., and Cs-L,z resonates at this frequency. C Linear half-wave tank section is employed as interstage coupler at 144 Mc. Inductor Lm resonates circuit to 50 Mc. tube V. directly for 50- 54 Mc. operation, or via a tripler stage V lt for 144- 148 Mc. operation. A...

NOTE

EXACT VALUE CRITICAL ONLY IN THAT IT SHOULD MATCH THE MATING UNIT CLOSELY. 70 p' Figure 3 SCHEMATIC DIAGRAM OF FIXED MOBILE SSB EXCITER C 70 ip-fd variable ceramic, Centralab 827B. Rs S00K linear taper potentiometer PS-1 Phase shift network package. See figure 7 Li, Li, L.I See figure 8 Ti Interstage audio transformer 1 3 . Stancor A-S3C used backwards. RFC Miniature 2.5 mh. choke. Millen J300-2500 X 80 meter crystal 3800 - 4000 kc. PC 3 turns 18 e. wire around...

Gridbias Modulator Circuit

On the control grid is controlled by the 70, 000-ohm wire-wound potentiometer and this potentiometer adjusts the average grid bias on the modulated stage. However, a-c signal voltage is also impressed on the control-grid of the tube and since the cathode follows this a-c wave the incoming speech wave is superimposed on the average grid bias, thus effecting grid-bias modulation of the r-f amplifier stage. An audio voltage swing is required on the grid of the 6B4G of approximately the same peak...

SSB Exciter for Fixed or Mobile

The simplest and most economical method of generating a single sideband signal is to employ a phasing-type transmitter of the form outlined in chapter 17 of this Handbook. If the r-f phasing system operates on the carrier frequency of the transmitter the complex frequency conversion circuits may be omitted and the complete exciter becomes inexpensive to build and simple to place in operation. A SSB exciter suitable for fixed or mobile operation is shown in figures 1 and 4. The exciter delivers...

Schematic Of Watt Triode Modulator With Bias Supply

Stancor A-4761 Ti Modulation transformer, 500 watt. Chicago Transformer Co. CMS-3 Tj 5 volts, 3 amp. Stancor P-6467 Tj Tapped bias transformer, 15-100 volts. UTC S-SI Tj 10 volt, 10 amp. Stancor P-6467 CHi 500 ma. splatter choke Chicago Transformer Co. SR-500 CHi 7 henry, 150 ma. Stancor C-7770 M 0 - 500 d.c. milliammeter SiA-B High voltage switch see text Figure 11 TEST SETUP FOR 500-WATT MODULATOR Figure 11 TEST SETUP FOR 500-WATT MODULATOR For c-w operation...

Variable Loudness Control For Use In Low Impedance Plate Circuits May Be Purchased As Irc Type Lc Loudness Control

Loudness The minimum threshold of Compensaton hearing and the maximum threshold of pain vary greatly with the frequency of the sound as shown in the Fletcher-Munson curves of figure 15. To maintain a reasonable constant tonal balance as the intensity of the sound is changed it is necessary to employ extra bass and treble boost as the program level is decreased. A simple variable loudness control is shown in figure 16 which may be substituted for the ordinary volume control used in most audio...

Figure A

Cutoff 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 wrapping of scotch electrical tape to exclude moisture. for 0 eta il see figure b 52 ohm rg-s u, any length the two wires may be spread either horizontally or vertically. FIGURE B remove outer jacket from a short length of cable as shown here. unbraid the shield of coax c. cutoff the dielectric and inner conductor flush with the...