Radio Handbook

The Autodyne Converter Circuit Using A Na As A Mixer

Transistor Autodyne

Signal from the collector to the emitter causing oscillation. Capacitor G tunes the oscillator circuit to a frequency 455 kc. higher than that of the incoming signal. The local oscillator signal is inductively coupled into the emitter circuit of the transistor. The incoming signal is resonated in T2 and coupled via a low impedance winding to the base circuit. Notice that the base is biased by a voltage divider circuit much the same as is used in audio frequency operation. The two signals are...

Dome Audiophaseshift Network

Degrees Phase Shifter

This circuit arrangement is convenient for obtaining the audio phase shift when it is desired to use a minimum of circuit components and tube elements. variable and should have a lower value of inductance than that value of inductance which would have the same reactance as resistor R. Inductor L may be considered as being made up of two values of inductance in parallel a a value of inductance which will resonate at the operating frequency with the circuit and tube capacitances, and b the value...

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...

G3sek 4cx1000 Grounded Grid Amplifier

4cx1000a Amplifier Schematic

5 turns, 1 4 copper tubing, 2 7 4 o.o., 3 long. capacitor G and G, the grid circuit bypass capacitor. Screen voltage may be removed for tune-up purposes by control switch Sa, section B. The screen circuit is grounded in the off and fil positions by means of switch section C. Amplifier The complete amplifier is Construction built upon an aluminum chassis measuring 13 x 17 x 3 and has a 14 standard relay rack panel. The Figure 40 GRID TANK CIRCUIT ASSEMBLY Coils are mounted to the ceramic switch...

See Fig For Filament Wiring

Pa300 Shematic

UNLESS OTHERWISE NOTED. SCHEMATIC, TRANSMITTER AND AUDIO SECTION OF TRANSCEIVER C5, C,, C 15 15 . ltd. Hammariund HFD-15X SsA-SiF Same as S,, figure 15. Space decks so coils L . and Lu fit between the decks. Cs, Cm 30 i ifd. Johnson 25J12 Ss SPOT push-button switch Di, Di Germanium diode 7N8J Si 2 pole, 3 position non-shorting switch. Mallory 3223-G La Lis See figure 21 for coil information RYi, RYs -See figure 19 RFC-, 7.0 fih. Ohmite Z-50 M, 0-1 d.c. milliammeter....

Single Sideband Signals

Operation Envelope Detector Circuit

Single-sideband signals may be received, after a certain degree of practice in the technique, in a quite adequate and satisfactory manner with a good communications receiver. However, the receiver must have quite good frequency stability both in the high-frequency oscillator and in the beat oscillator. For this reason, receivers which use a crystal-controlled first oscillator are likely to offer a greater degree of satisfaction than the more common type which uses a self-controlled oscillator....

Typical Avc Circuit Using A Double Diode

Avc Circuits

Any of the small dual-diode tubes may be used in this circuit. Or, if desired, a duo-diode-triode may be used, with the triode acting as the first audio stage. The left-hand diode serves as the detector, while the right-hand side acts as the a-v-c rectifier. The use of separate diodes for defector and a-v-c reduces distortion when receiving an AM signal with a high ages on the b-f-o tube is changed, as the latter circuits usually change the frequency of the b.f.o. at the same time they change...

Showing The Effect Of Cathode Lead Inductance

1905 Schematic

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...

Block Diagram Of Meter Transceiver

Crystal Radio Reciever Block Diagram

Twenty tubes plus selenium rectifier power supply provide de-luxe operation for the advanced VHP enthusiast. Power supply may be operated from either automobile electrical system or 115 volts, a.c. 6AL5 (Vn) is employed as detector, a-v-c, and a-n-1 tube. The noise limiter is of the low distortion type and is left in the circuit at all times. One section of the 6AL5 serves as the a-v-c rectifier, and the resulting voltage is applied to four i-f tubes for smooth a-v-c action on strong signals....

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...

The Multee Twoband Antenna

This compact antenna can be used with excellent results on 160 80 and 80 40 meters. The feedline should be held as vertical as possible, since it radiates when the antenna is operated on its fundamental frequency. The Multee An antenna that works well Antenna on 160 and 80 meters, or 80 and 40 meters and is sufficiently compact to permit erection on the average city lot is the W6BCX Multee antenna, illustrated in figure 23- The antenna evolves from a vertical two wire radiator, fed on one leg...

Vhf Rhombic Antenna Design Chart

The optimum tilt angle see figure II for zero-angle radiation depends upon the length of the sides. 10 to 16 db gain with a simpler construction than does a phased dipole array, and has the further advantage of being useful over a wide frequency range. Except at the upper end of the v-h-f range a rhombic array having a worthwhile gain is too large to be rotated. However, in locations 75 to 150 miles from a large metropolitan area a rhombic array is ideally suited for working into the city on...

Alternative Reactancetube Modulator

This circuit is often preferable for use in the lower frequency range, although It may be used at 7.75 Mc. and above if desired. In the schematic above the reactance tube is shown connected across the voltage-divider capacitors of a Clapp oscillator, although the modulator circuit may be used with any common type of oscillator. However, better control of the operating conditions of the modulator may be had through the use of a variable capacitor as C3. Resistance R will usually have a value of...

Allband Ag Crystal Oscillator Capable Of Driving Beam Pentode Tube

Maximum output, as the oscillator then is in a more stable condition and sure to start immediately when power is applied. This is especially important when the oscillator is keyed, as for break-in c-w operation. Crystal Switching It is desirable to keep stray shunt capacitances in the crystal circuit as low as possible, regardless of the oscillator circuit. If a selector switch is used, this means that both switch and crystal sockets must be placed close to the oscillator tube socket. This is...

Talkie for Mc

Antennascope

The 144 Mc. band is the ideal frequency range for short-haul, portable equipment. Little power is required for local coverage, and the antenna size is moderate. Then too, this is just about the highest frequency at which filament type battery tubes will operate. Shown in the accompanying illustrations is a battery powered, crystal controlled handie-talkie designed for operation in the 2 meter region. It is especially well suited for Gvil Defense work or emergency service. This unit was designed...

Tor and new principles must be enlisted In

General, the improvements embodied in existing tubes have consisted of 1 reducing electrode spacing to cut down electron transit time, 2 reducing electrode areas to decrease interelectrode capacitances, and 3 shortening of electrode leads either by mounting the electrode assembly close to the tube base or by bringing the leads out directly through the glass envelope at nearby points. Through reduction of lead inductance and interelectrode capacitances, input and output resonant frequencies due...

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...

Coil Chart For Mc Transmitter

Ll - 144 mc. coil 3 6 T. 24 E., 1 2 DIA. millen 69016 FORM. L2- 50 mc. coil 28 T. 24 E., 1 2DIA. millen 69046 FORM. L3- 52 TURNS 28 E. m llen 69046 FORM. 1-4- 22 T. CENTER TAP, 3 4 Dl A., 32 T. P. I. b amp w 3012 _5- 15 T. CENTER TAP, 1 2 DIA., 1 6 T.P. I. biw 3003 LINK COIL ONE TURN HOOKUP WIRE. L6- 2 1 2 T. CENTER TAP, 1 2 DIA. 16 T. P. I . bs w 300 3 LINK COIL ONE TURN HOOKUP WIRE. L - 7 T. CENTER TAP, 5 6 DIA., 16 T.P. I. bi w 3007 LINK CO I L ONE TURN HOOKUP WIRE. L8- 50 mc. it. CENTER...

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...

Block Diagram And Parts Layout Of Mc Sideband Transmitter

Fourteen tubes including two voltage regulators are used in this compact transmitter. A Crosby modulator and 500 kc. Collins Mechanical Filter are employed for sideband generation. First frequency conversion is to 4 Mc., and second frequency conversion is to 14 Mc. Layout of major components on both sides and front of special chassis is shown in the illustration. Figure 25 OBLIQUE VIEW OF AMPLIFIER AND EXCITER CHASSIS The power amplifier chassis is at the left. The plate coil, plate tuning...

Schematic Of Amateur Band Receiver

Tube Comunication Receiver Schematic

The front-end circuit is shown in Figure 18A. The tuning capacitors placed across the input and output circuits of the mechanical filters are determined by the choice of filter. See filter specification sheet. Type F455C filters were used in this receiver. M 0-1 d-c milliammeter, 1-inch diameter SiA-B DPDT rotary switch. Centralab PA-2001 decks, with Centralab PA-302 index assembly SiA-B-C-D 4 pole, 3 position switch. Centralab PA-1013 T 1500 kc. i-f transformer. J. W. Miller Co. 5I2-W1. Remove...

Highpass Transmission Line Filters

The arrangement at A will stop the passing of all signals below about 45 Mc. from the antenna transmission line into the TV set. Coils Li ore eoefi 7.2 micro ienrys 17 turns no. 24 enam. closewound on -inch dia. polystyrene rod with the center tap grounded. It will be found best to scrape, twist, and solder the center tap before winding the coil. The number of turns each side of the tap may then be varied until the tap is in the exact center of the winding. Coil L2 is 0.6 microhenry 12 turns...

Twin Noise Squelch Circuit

C O.I- 2fd. paper 50-M -fd. mica C3 100- MM- mica Q, C5 0.01-Mfd. paper R1 R2 1 megohm, 'A watt NOISE LIMITER CIRCUIT, WITH ASSOCIATED A-V-C This limiter is of the series type, and is self-adjusting to carrier strength for phone reception. For proper operation several volts should he developed across the secondary of the last i-f transformer FT under If this feature is not provided, the b-f-o injection should be reduced to the lowest value that will give a satisfactory beat. When this is done,...

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...

Double Extended Zepp Antenna

For best results, antenna should be tuned to operating frequency by means of grid-dip oscillator. Col near The simple colinear antenna array Arrays is a very effective radiating system for the 3.5-Mc. and 7.0-Mc. bands, but its use is not recommended on higher frequencies since such arrays do not possess any vertical directivity. The elevation radiation pattern for such an array is essentially the same as for a half-wave dipole. This consideration applies whether the elements are of normal...

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....

Triode Tubes

Ated Class AB in other words the tubes may be operated with bias and input signals of such amplitude that the plate current of alternate tubes may be cut off during a portion of the input voltage cycle. If a tube were operated in such a manner in a single-ended amplifier the second harmonic amplitude generated would be prohibitively high. , Push-pull Class AB operation allows a plate circuit efficiency of from 45 to 60 per cent to be obtained in an amplifier stage depending upon whether or not...

Signalstrengthmeter Circuits

Shown above are four circuits for obtaining a signal-strength reading which Is a function of incoming carrier amplitude. The circuits are discussed lln the accompanying text. with respect to strength. This is because increased a-v-c bias on stronger signals causes lower plate current through the meter. For this reason, special meters which indicate zero at the right-hand end of the scale are often used for signal strength indicators in commercial receivers using this type of circuit....

National R-100 Choke

Rfc National Type 100 Choke

TRANSMITTER SECTION RECEIVER SECTION Ci, C,, Cj, Ci 10-10 liufd. Johnson 11MB11 Cs, C gt , Cm, Cn i ifitd. Erie 3139-f SCHEMATIC, R-F SECTION OF TRANSMITTER-RECEIVER TRANSMITTER SECTION RECEIVER SECTION Ci, C,, Cj, Ci 10-10 liufd. Johnson 11MB11 Cs, C gt , Cm, Cn i ifitd. Erie 3139-f S4' CiT4 'L Jd l''e 3Io ,E, RfCt Ohmite Z-235 r-f choke C7 70 f-tifd. Johnson 9Mlt _ _ . . RFCi_Ohmite Z-28 r-f choke T' Ti 4-5 Mc- ''erstoge i-f transformer. J. W. Miller 1466 RFCz Ohmite Z-235 r-f choke PLi 6...

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...

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...

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...

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...

Schematic Of Transistorized Forty Meter Ssb Exciter

Variable ceramic capacitor. Centralab 823-DZ i 35 turns 22 enamel, y2 diam., closewound on National XR-50 form. Start with two turn bifllar winding see figure 8, section 28-7 for bifilar detail . Mount coil assembly in small shield can. L , L lt Same as Li. Mount L in small shield can. L, Same as L,. Tap IS turns from cold end. Mount in small shield can. RFC 2.5 mh. miniature r-f choke. Millen 1300 - 2500 Ti- IK pri., 60 ohm sec. transistor transformer. Chicago UM-lll Ti SSK sec.,...

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...

Neutralizing Circuits For Beam Tetrodes

Transformer Circuit Diagram

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,...

Colpitts Harmonic Oscillator

CRYSTAL L 10 T. 3011 B amp W MINIDUCTOR, TAP AT 3T. FROM GRID END FOR SMC. CRYSTAL L 10 T. 3011 B amp W MINIDUCTOR, TAP AT 3T. FROM GRID END c REGENERATIVE HARMONIC OSCILLATOR 200 v. Ll ST. I8, -jf D. SPACED L.Z-IT. HOOKUP WIRE, D. CATHODE FOLLOWER OVERTONE OSCILLATOR V.H.F. OVERTONE OSCILLATOR

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...

Simple Watt Phasing Type Ssb Exciter

6ba6 Receiver

Pole double-throw switch in the output circuit of the cathode follower permits sideband selection. A Filter-Type Exciter for 80 and 40 Meters A simple SSB filter-type exciter employing the Collins mechanical filter illustrates many of the basic principles of sideband generation. Such an exciter is shown in figure 39. The exciter is designed for operation in the 80 or 40 meter phone bands and delivers sufficient output to drive a class ABi tetrode such as the 2E26, 807, or 6146. A conversion...

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....

Water Cooled Linear Amplifier Packaged For Fixed Station

Either 4W-300B water cooled tubes or 4X-2S0B air cooled tubes may be employed in this compact linear amplifier. Input and out' put capacitors of pi-network are vacuum units, and power supply three phase is contained within the cabinet right . Wide band plate r.f. choke is at left of cabinet, running from front to back. Amplifier operates at plate potential of 3000 volts, with p.e.p. of 1500 watts. under overload conditions and the silicon rectifiers cannot be damaged, even with a direct short...

Watt Transistor Power Supply For Volt Automotive System

Ti Transistor power transformer. 12 volt primary to provide 275 volts at 125 ma. Chicago Standard DCT-2. Di-D , Sarkes-Tarzian silicon rectifier, type M-500 paper. Some types of paper capacitors are wax-impregnated, but the better ones, especially the high-voltage types, are oil-impregnated and oil-filled. Some capacitors are rated both for flash test and normal operating voltages the latter is the important rating and is the maximum voltage which the capacitor should be required to withstand...

Th Edition To ble of Contents

INTRODUCTION TO 1-1 Amateur Radio 1-2 Station and Operator Licenses 1-3 The Amateur Bands 1-4 Starting Your Study Chapter Two. DIRECT CURRENT 2-1 The Atom 2-2 Fundamental Electrical Units and 2-3 Electrostatics Capacitors 2-4 Magnetism and Electromagnetism 2-5 RC and Rl Transients Chapter Three. ALTERNATING CURRENT 3-1 Alternating Current 3-2 Resonant Circuits 3-3 Nonsinusoidal Waves and Transients 3-4 Transformers 3-5 Electric Filters Chapter Four. VACUUM TUBE 4-1 Thermionic...

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...

Major Components

The VFO is built upon two Ya-inch dural plates, one forming the base and the other forming the front of the oscillator enclosure. Inductor Li and padding capacitors are mounted to front wall, and the variable tuning capacitor is bolted to base. Oscillator tube (V-l) projects from far wall of enclosure to remove as much heat from tuned circuit as possible. Entire VFO is mounted upon miniature shock mounts and dial is attached to VFO unit, rather than to rack panel. 6AG7 and 2C26 tubes are at...

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...

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...

Interior View Of Balanced Bridge Showing Parts Placement

Diode rectifiers are placed at right angles to the short section of transmission line. Both sides of bridge are balanced to ground by virtue of symmetrical construction of unit. broken by two 250 ohm composition resistors and switch Si. The line segments are made of short pieces of 10 copper wire, running between the various components. Spacing between the wires is held close to three inches to approximate a 500-600 ohm line. The small components of the bridge are placed symmetrically about the...

Pushpull Frequency Tripler

The push-pull tripler is advantageous In the v-h-f range since circuit balance is maintained both In the input and output circuits. If the circuit is neutralized it may be used either as a straight amplifier or as a tripler. Either triodes or tetrodes may be used dual-unit tetrodes such as the 815, 832 , and 829B are particularly effective in the v-h-f range. center tap of the grid coil being by-passed to ground . Push-Pull Frequency It is frequently desirable Triplers in the case of u-h-f and...

Silicon Rectifier Characteristics

A Reverse direction of silicon rectifier is characterized by extremely high resistance up to point of avalanche voltage. B Threshold voltage of silicon cell is about 0.6 volt. Once device starts conducting the current increases exponentially with small increments of voltage, then nearly linearly on a very steep slope. HIGH CURRENT SUPPLY 900 WATT HIGH VOLTAGE SUPPLY Figure 16 SEMI-CONDUCTOR POWER SUPPLIES HIGH CURRENT SUPPLY 900 WATT HIGH VOLTAGE SUPPLY Figure 16 SEMI-CONDUCTOR POWER SUPPLIES A...

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...

Block Diagram Of Phasingtype Sideband Exciter

Only fire tubes ore required in this simple phasing-type sideband exciter. Audio system has sufficient gain to operate from crystal microphone. ohms in the center of the 80 meter phone band. Bridge balance and carrier elimination is achieved by adjustment of the variable potentiometers R8, Rfi, Rio in the bridge circuit. Four selenium diodes are used in the modulator circuit. A 1N82 multiple diode assembly may be employed, or four 1N81 diodes whose front back ratios are equal may be used. The...

Feeding A Quarterwave Marconi Antenna

When an open-wire line is to be used, it may be link coupled to a series-resonant circuit between the bottom end of the Marconi and ground, as at A . Alternatively, a reasonably good impedance match may be obtained between 52-ohm coaxial line and the bottom of a resonant quarter-wave antenna, as illustrated at B above. sible above ground. Raising the maximum-current point in the radiator above ground has two desirable results The percentage of low-angle radiation is increased and the amount of...

The Cubicalquad Antenna For The Meter Band

Zepp Antenna

When tuned feeders are employed, the Bi-Square array can be used on half frequency as an end-fire vertically polarized array, giving a slight practical dx signal gain over a vertical half-wave dipole at the same height. A second Bi-Square serving as a reflector may be placed 0.15 wavelength behind this antenna to provide an overall gain of 8.5 db. The reflector may be tuned by means of a quarter-wave stub which has a moveable shorting bar at the bottom end. The stub is used as a substitute for...

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...

Clipper Amplifier

The near-ultimate in talk power can be obtained with low level clipping and filtering combined with high level filtering. Such a modulation system will have real punch, yet will sound well rounded and normal. The speech amplifier described in this section makes use of low level clipping and filtering and is specifically designed to drive a pair of push-pull 810 modulators such as shown in Section Three. Circuit The schematic of the speech Description amplifier-clipper is shown in figure 15. A...

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....

Foreword To The Fifteenth Edition

Over two decades ago the historic first edition of the RADIO HANDBOOK was published as a unique, independent, communications manual written especially for the adv meed radio amateur and electronic engineer. Since that early issue, great pains have been taken to keep each succeeding edition of the RADIO HANDBOOK abreast of the rapidly expanding field of electronics. So quickly has the electron invaded our everyday affairs that it is now no longer possible to segregate one particular branch of...

Underchassis View Of Cathode Driven Amplifier

Input coaxial connector is at the right on rear of chassis. Mica filament bypass capacitors are placed between the tube sockets, with RFCi beneath them. 29-8 A Low Distortion Sideband Linear Amplifier A properly designed grounded grid linear amplifier is a very satisfactory high level stage for a sideband transmitter, even though the possibility of taking advantage of the inherent feedback is lost because of the reasons explained in Section 29-7 of this chapter. With care, a...

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...

Watt Modulator Using Tubes

Stancor A-53 lz Poly-pedance Class B driver transformer. 2 1 ratio. Stancor A-4761 7 j 500 watt output transformer. 18K primary, 6.2SK secondary. Chicago CMS-3 T, 10 volts, 70 amperes, Stancor C-6467 M 0 - 500 ma. 350 watts of audio are obtainable from this circuit at plate potential of 2000 volts. Despite the fact that complete transmitters may be purchased at moderate cost many amateurs still prefer to build their station equipment. The experience gained in...

Reactancetube Modulation Of Crystal Oscillator Stage

Phase-Modulation A simple reactance modula-Circuits tor normally used for FM may also be used for PM by connecting it to the plate circuit of a crystal oscillator stage as shown in figure 11. Another PM circuit, suitable for operation on 20, 15 and 10 meters with the use of 80 meter crystals is shown in figure 12. A double triode 12AX7 is used as a combination Pierce crystal oscillator and phase modulator. C, should not be thought of as a neutralizing condenser, but rather as an adjustment for...

The Fremodyne Superregenerative Superheterodyne Detector For Frequency Modulated Signals

Superregenerative receivers radiate a strong, broad, and rough signal. For this reason, it is necessary in most applications to employ a radio frequency amplifier stage ahead of the detector, with thorough shielding throughout the receiver. The Fremodyne The H a z e 11 i n e - Fremodyne Detector superregenerative circuit is expressly designed for reception of FM signals. This versatile circuit combines the action of the superregenerative receiver with the superhetrodyne, converting FM signals...

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...

A VHF Transceiver of Advanced Design

Modern tubes and circuit techniques permit sensitivity and stability levels to be achieved in the VHF region that were possible only at the lower frequencies a few years ago. The transceiver described in this section makes full use of these advanced circuits to produce superb results in the amateur 50 Mc. and 144 Mc. bands. The transceiver pictured in figure 12 comprises a complete VHF station and power supply in one small, streamlined cabinet. The transmitter section is crystal controlled on...

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...

Twocavity Klystron Oscillator

A conventional two-cavity klystron Is shown with a feedback loop connected between the two cavities so that the tube may be used as an oscillator. motion, the velocity of the electrons in the beam is increased. Conversely, when the field becomes increasingly negative in the direction of the beam corresponding to the other half cycle of the exciting voltage from that which produced electron acceleration the velocity of the electrons in the beam is decreased. When the velocity-modulated electron...

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...

Audio Phaseshift Network And Test Layout

NOTE two parallel pieces of hookup wire are wound simultaneously over primary winding to make b ft la ff secondary. bottom end of one winding and top end of opposite winding are grounded to mounting lug on coil form. NOTE two parallel pieces of hookup wire are wound simultaneously over primary winding to make b ft la ff secondary. bottom end of one winding and top end of opposite winding are grounded to mounting lug on coil form. Figure 8 BIFILAR COIL FOR SSB TRANSMITTER (Li) Coils Li and L,...

Unidirectional Alldriven Arrays

A unidirectional all-driven end-fire array is shown at A . B shows an array with two half waves in phase with driven reflectors. A Lazy-H array with driven reflectors is shown at C . Note that the directivity is through the elements with the greatest total feed-line length in arrays such as shown at B and C . be used in place of a parasitic array of similar dimensions when greater frequency coverage than is available with theyagi type is desired. Figure 13B is a combination end-fire and co-...

Centertap Keying With Click Filter

The constants shown above are suggested as starting values considerable variation in these values can be expected for optimum keying of amplifiers of different operating conditions. It is suggested that a keying relay be substituted for the key in the circuit above wherever practicable. true of all oscillators, whether electron coupled or crystal controlled. The more amplifier or doubler stages that follow the keyed stage, the more difficult it is to hold control of the shape of the keyed...

Vacuum Tube Amplifiers

The ability of the control grid of a vacuum tube to control large amounts of plate power with a small amount of grid energy allows the vacuum tube to be used as an amplifier. It is this ability of vacuum tubes to amplify an extremely small amount of energy up to almost any level without change in anything except amplitude which makes the vacuum tube such an extremely valuable adjunct to modern electronics and communication. Symbols for As an assistance in simplify-Vacuum-Tube ing and shortening...

Pentode Or Tetrode

STATIC INTERELECTRODE CAPACITANCES WITHIN A TRIODE, PENTODE, OR TETRODE Np plate efficiency (expressed as a decimal) 6p one-half angle of plate current flow 0g one-half angle of grid current flow Rl load resistance Zl load impedance Vacuum-Tube The relationships between cer-Constants tain of the electrode potentials and currents within a vacuum tube are reasonably constant under specified conditions of operation. These relationships are called vacuum-tube constants and are listed in the data...

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...

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...

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...

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...

Twin Triode Mixer Circuit For Ssb Frequency Conversion

Double Conversion Ssb Receiver Schematic

Push-pull circuits and the tubes into exact amplitude and phase balance, about 20 db of injection frequency cancellation is all that can be depended upon. With suitable trimming adjustments the cancellation can be made as high as 40 db, however, in fixed frequency circuits. The Twin Triode Mixer The mixer circuit shown in figure 28 has about 10 db lower distortion than the conventional 6BE6 converter tube. It has a lower voltage gain of about unity and a lower output impedance which loads the...

Ionospherereflection Wave Paths

Showing typical ionosphere-reflection wave paths during daylight hours when Ionization density is such that frequencies as high as 28 Mc. wIII be returned to earth. The distance between ground-wave range and that range where the ionosphere-reflected wave of a specific frequency first will be returned to earth is called the skip distance. zon, the farther away will the wave return to earth, and the greater the skip distance. The wave can be reflected back up into the ionosphere by the earth, and...

Transmitter Keying and Control

It is probable that the average amateur station that has been in operation for a number of years will have at least two transmitters available for operation on different frequency bands, at least two receivers or one receiver and a converter, at least one item of monitoring or frequency measuring equipment and probably two, a v.f.o., a speech amplifier, a desk light, and a clock. In addition to the above 8 or 10 items, there must be an outlet available for a soldering iron and there should be...

Remote Cutoff Grid Structure

- GRID VOLTS o Figure 19 ACTION OF A REMOTE CUTOFF GRID STRUCTURE tive with respect to the minimum plate voltage. The secondary electrons that would travel to the screen if there were no suppressor are diverted back to the plate. The plate current is, therefore, not reduced and the amplification possibilities are increased figure 17 . Pentodes for audio applications are designed so that the suppressor increases the limits to which the plate voltage may swing therefore the consequent power...

Time Sequence Of A Differential Keyer

On a moment before the rest of the stages are energized, and remains on a moment longer than the other stages. The chirp or frequency shift associated with abrupt switching of the oscillator is thus removed from the emitted signal. In addition, the differential keyer can apply wave shaping to the amplifier section of the transmitter, eliminating the click caused by rapid keying of the latter stages. The ideal keying system would perform as illustrated in figure 17. When the key is closed, the...

Schematic Of Watt Music System Amplifier

Is to cross-connect the two plate leads of the 6AQ5 tubes. If the feedback polarization is incorrect, the amplifier will oscillate at a supersonic frequency and the reproduced signal will sound fuzzy to the ear. The correct connection may be determined with the aid of an oscilloscope, as the oscillation will be easily found. The builder might experiment with different values of feedback resistor Ri, especially if a speaker of different impedance is employed. Increasing the value of Ri will...

Schematic Of A Highvoltage Peak Voltmeter

A peak voltmeter such as diagrammed above is convenient for the measurement of peak voltages at fairly high power levels from a source of moderately low impedance. Ci ,001-jifd. high-voltage mica Ct 7.0 id. high-voltage paper Ri 500,000 ohms two 0.25-megohm ' j-watt in series Rz 1.0 megohm four 0.25-megohm 'A-woft in series T 2.5 v., J.75 a. filament transformer M 0-1 d-c milliammeter hi i.o S-p-d-t toggle switch S S-p-s-t toggle switch Note Ci is a by-pass around Ci, the inductive reactance of...

Nbfm Adapter For Kc If System

Volts peak for the maximum deviation which can be handled by a conventional 455-kc. i-f system. The unit may be tuned by placing a high resistance d-c voltmeter across Rt and tuning the trimmers of the i-f transformer for maximum voltage when an unmodulated signal is injected into the i-f strip of the receiver. The voltmeter should next be connected across the audio output terminal of the discriminator. The receiver is now tuned back and forth a-cross the frequency of the incoming signal, and...

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...

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...

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...

The Endfed Hertz Antenna

Showing the manner in which an end-fed Hertz antenna may be fed through a low-impedance line and low-pass filter by using a resonant tank circuit as at A , or through the use of a reverse-connected pi network as at B . Some harmonic-attenuating provision in addition to the usual low-pass TVI filter must be included in the coupling system, as an end-fed antenna itself offers no discrimination against harmonics, either odd or even. The end-fed Hertz antenna has rather high losses unless at least...

Twoband Marconi Antenna For Meter Operation

Since this antenna type is an unbalanced radiating system, its use is not recommended with high-power transmitters where interference to broadcast listeners is likely to be encountered. The r-f voltages encountered at the end of zepp feeders and at points an electrical half wave from the end are likely to be quite high. Hence the feeders should be supported an adequate distance from surrounding objects and sufficiently in the clear so that a chance encounter between a passerby and the feeder is...

Simple Compensated Video Amplifier Circuit

Resistor R in conjunction with coil L serves to flatten the high-frequency response of the stage, while CB and RB serve to equalize the low-frequency response of this simple video amplifier stage. ohms connected directly between grid and cathode of the tube. The cathode is grounded. Grid current flows at all times, and the effective input resistance is about one-half the resistance value of the grid leak. This circuit is particularly well suited as a high gain amplifier following low output...

Cathodetap Regeneration With Screen Voltage Regeneration Control

Ance with the pulsating current they audibly reproduce the modulation which was placed upon the carrier wave. The operation of the detector circuit is shown graphically above the detector circuit in figure 1. The modulated carrier is shown at A, as it is applied to the antenna. B represents the same carrier, increased in amplitude, as it appears across the tuned circuit. In C the varying d-c output from the detector is seen. REGENERATIVE DETECTOR CIRCUITS Regenerative detectors are seldom used...

Coil Neutralized Amplifier

This neutralization circuit is very effective with triode tubes on any frequency, but Is particularly effective in the v-h-f range. The coil L is adjusted so that it resonates at the operating frequency with the grid-to-plate capacitance of the tube. Capacitor C may be a very small unit of the low-capacitance neutral izing type and is used to trim the circuit to resonance at the operating frequency. If some means of varying the inductance of the coil a small amount is available, the trimmer...

Conventional Triode Frequency Multiplier

Small triodes such as the 6C4 operate satisfactorily as frequency multipliers, and can deliver output well into the v-h-f range. Resistor R normally will have a value in the vicinity of 100,000 ohms. given output, because a moderate amount of power is delivered to the amplifier load by the driver stage of a grounded-grid amplifier. Quartz crystals and variable-frequency oscillators are not ordinarily used for direct control of the output of high-frequency transmitters. Frequency multipliers are...

The carrier level of a conventional screen

Modulated stage the plate-voltage swing of the modulated tube is one-half the voltage swing at peak-modulation level. This condition must exist in any type of conventional efficiency- modulated stage if 100 per cent positive modulation is to be attainable. Since the plate-voltage swing is at half amplitude, and since the screen voltage is at half its full-modulation value, the screen current is relatively low. But at the positive modulation peak the screen voltage is approximately doubled, and...

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...

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...

Foldedtop Dualband Antenna

14 wire spaced 4 to 6 inches the antenna system is sometimes called a center-fed zepp. With this type of feeder the impedance at the transmitter end of the feeder varies from about 70 ohms to approximately 5000 ohms, the same as is encountered in an end-fed zepp antenna. This great impedance ratio requires provision for either series or parallel tuning of the feeders at the transmitter, and involves quite high r-f voltages at various points along the feed line. If the feed line between the...

The tank circuit operates in the same manner whether the tube feeding it is a pentode

Beam tetrode, neutralized triode, grounded-grid triode, whether it is single ended or push- i 2 3 5 7 10 20 30 50 100 200 500 CORRECT VALUES OF TANK CIRCUIT CAPACITANCE (Cl OPERATING Q OF 6 WITH PUSH-PULL TANK CIRCUITS i 2 3 5 7 10 20 30 50 100 200 500 CORRECT VALUES OF TANK CIRCUIT CAPACITANCE (Cl OPERATING Q OF 6 WITH PUSH-PULL TANK CIRCUITS

Grid Parasitic Suppressors In Pushpull Triode Stage

Winding these small coils of iron or nichrome wire may sometimes be of assistance. To increase losses at the parasitic frequency, the parasitic coils may be wound on 100-ohm 2-watt resistors. These lossy suppressors should be placed in the grid leads of the tubes close to the grid connection, as shown in figure 16. Parasitics with Where beam-tetrode tubes are Beam Tetrodes used in the stage which has been found to be generating the parasitic oscillation, all the...