A UNIT OSCILLATOR FOR THE 0.5- TO 50-MC RAN GE

�Uo. IN THIS ISSUE

Page ExPER £MENTER INDEX 4

•THE TYPE 1211-A Unit Oscillator, lat­est addition to the rapidly growing line of

General Radio Unit Oscillators\ extends

the frequency range covered by the ver-satile units downward by a factor of 100.

This new oscillator has a frequency span of 0.5-50 Mc, which is covered in two logarithmic ranges. The output power is well over one

1Eduard Karplus, ''V-H-F and U-H-F Unit Oscillators," General Radio Experimenter, Vol. 24, No. 12, �vlay, 1950. A.G. Bousquet, "A New Unlt Oscillator-50 to 250 Mc," General Radio Experim"'Yiter, Vol. 27, No. 8, .January, 19.-3.

Figure 1. View of the Type 1211-A Unit Oscillator.

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GENE.RAL RA DIO EXPERIMENTER 2

watt over the 0.5-to-5 Mc range and is at least 200 milliwatts over the 5-to-50

Mc range. The frequency is indicated

directly on a six-inch dial, and approxi­mate increments of frequency expressed

in percentage are given on a 3�-inch slow-motion-drive dial.

To avoid the necessity of frequent

range switching, the tuning ranges have been made as wide as possible. The span of each of the two ranges in the TYPE 1211-A Oscillator is 10 to 1. This wide frequency range is obtained by varying simultaneously the capacitance and the inductance as the frequency dial is turned. A frequency change of about 5

to 1 is due to the variable capacitor, and the remaining 2 to 1 frequency change results from inductance varia­

tion.

Electrical Circuit

The TYPE 1211-A Unit Oscillator uses

a Hartley circuit with a TYPE 5763 os­

cillator tube. This tube type was se­lected because it can handle all the power provided by the TYPE 1203-A Unit Power Supply. The output circuit

is coupled inductively to the oscillator tuned circuit and includes a voltage divider as output control.

An audio oscillator can be connected

to terminals in series with the plate supply for direct amplitude modulation

of the oscillator. A convenient audio source is the TYPE 1214-A Unit Oscil-

lator which yields about 25 per cent modulation at 400 or 1000 cycles. The envelope distortion at this modulation

level is around two to four per cent, de­

pending on the carrier frequency. Since modulation is accomplished

directly in the oscillator circuit, some unwanted frequency modulation is un­avoidable. Amplitude modulation prac­tically free of frequency modulation can be obtained at carrier frequencies above 10 Mc by using the TYPE 1000-P6 Crystal Diode Modulator.

Construction

The oscillator circuj t is assembled on an aluminum casting with filtering com­ponents mounted within the casting. A spun-aluminum cylindrical cover com­pletes the shielding much more eff ec­tively than would a conventional rec­tangular dust cover. The output control and the coaxial output connector are

at the rear of the cover; the entire as­

sembly is mounted on an L-shaped panel and base.

The tuning capacitor and the switch contacts are the same as those used in

the TYPE 1001-A Signal Generator and TYPE 1330-A Bridge Oscillator.

The 0.5- to 5-Mc and the 5- to 50-Mc oscillator coils are arranged in a plane

perpendicular to the tuning capacitor

shaft, and range selection is obtained by switching in the appropriate coil by means of a rocker arm on the panel. The

Figure 2. Elementary Schematic Diagram of tke Type 1211-A Unit Oscillator.

MOD.

B+

B-

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3

frequency ranges are engraved at the arm extremities, and the main frequency

dial shields one end of the arm so that only the range selected is indicated.

The core assembly, which helps to produce the wide frequency span, i s con­centric with the coils and is mounted to turn with the capacitor shaft.

This assembly consists of a dust core and an aluminum core, both of a sickle shape, to produce a smooth transition from full iron-dust core for maximum inductance through a mini­mum of core to a full aluminum core for minimum inductance. The cores and the tuning capacitor plates are shaped to yield an approximate logarithmic re­sponse of frequency with angular rota­tion over the 10-to-1 frequency span.

(See Figure 3.) The iron-dust core in­creases the circuit Q, while the aluminum core reduces it.

Features

The major features of this oscillator are the compact unit design, the 10-to-l frequency range for each switch position, and the approximately logarithmic fre­quency response of the main dial with a smaller auxiliary dial indicating fre­quency increments of 0.2% per division .

The 874-type coaxial output system and the effective shielding add appreciably to the usefulness of the instrument. All

power leads are carefully filtered, and the dial shaft is enclosed within a

5

4

2

t3 _J

�15 0 <t l9 l.LJ �

I

.7

.5

SEPTEMBER, 1953

0 60 120

ANGULAR ROTATION- DEGREES

Figure 3. Frequency versus rotation angle showing the effect of the metal cores.

grounded capsule inside the ma.in knob. The shielding is entirely adequate for

use of the oscillator as a power source in bridge measurements. The 874-type coaxial output connector permits ex­tension of the shield systei;p. to the bridge.

Since all leads to the power unit are carefully filtered, batteries can be used as the power supply for field applica­tions. For general laboratory operation, the TYPE 1203-A Unit Power Supply is recommended.

- A. G. BOUSQUET

SPE CIFI CATIONS

Frequency Range: 0.5 to 50 Mc in two ranges. Frequency Calibration Accuracy: 2% at no load. Frequency Controls: A two-position range switch. A 6-inch dial with calibration approximately logarithmic against angular rotation. A slow­motion vernier dial to indicate frequency in­crements of 0.2 % per dial division. Output System: The oscillator output is avail­able at a coaxial connector at the rear of the instrument. An adjacent ground terminal also permits connection by means of a TYPE 274-M

Plug. The output is controlled by a small dial calibrated in arbitrary units.

Output Power: At least 200 milliwatts into a 50-ohm load at any frequency within the range. For the 0.5-5 Mc range, the output power is of the order of 2 watts.

Modulation: Direct amplitude modulation over the audio-frequency range can be obtained with an external audio oscillator. The im­pedance at the modulation terminals is about 8000 ohms, and 25% modulation is obtained

180

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GENER AL R ADIO EXPERIMENTER 4

with about 45 volts audio. Under these con­ditions, envelope distortion is of the order of 3 % and is a function of carrier frequency set­ting. The audio source must be capable of carrying the de of the carrier oscillator.

To obtain amplitude modulation free of in­cidental f-m, the TYPE 1000-P6 Crystal Diode Modulator can be used at the carrier fre­quencies above 10 Mc, at reduced output.

Circuit: Hartley oscillator coupled direct to out­put. Frequency tuning is obtained by simul­taneously changing the tuning capacitance and the position of the core in the coils (iron­dust core to aluminum core).

Power Supply Requirements: 300 volts at 50 ma de, 6.0 volts at 0. 75 amperes ac or de. The TYPE 1203-A Unit Power Supply is recom­mended.

Type

Tube: TYPE 5763 Miniature VHF Beam Power Amplifier, which is supplied with the instru­ment. Mounting: The oscillator is mounted on an alu­minum casting and is shielded with a spun­aluminum cover. The ass mbly is mounted on an L-shaped panel and chassis, finished in black-crackle lacquer. Accessories Supplied: TYPE 874-R21 Patch Cord, TYPE 874-Q2 Adaptor and TYPE CDMS-466-4 Multipoint Connector. Accessories Available: TYPE 1000-P6 Crystal Diode Modulator, TYPE 1214-A Unit Oscil­lator, TYPE 1203-A Unit Power Supply, TYPE 1204-B Unit Variable Power Supply, and the TYPE 874 Coaxial Elements. Dimensions: 7 x 8 x 12 inches over-all.

Net Weight: 11� pounds.

Code Word Price

1211- A j Unit Oscillator . • . • . . . . • . . • • • • • • • • . . . • . • . . . • . • . • j ATLAS $295.00 U. S. Patents 2,125,816 and 2,548,457.

INDEX

TO GENERAL RADIO EXPERIMENTER

Volumes XXVI and XXVll, June, 1951, through May, 1953

INDEX BY TITLE

ACCESSORIES, THE VACUUM-TUaE BRIOG. NU ITS (A. G. Bousquet: eptcmber, 1952)

AccE soruE - ADAPTOR , L1 E STRETCHER, CoM-PONE T Mo T, BAL , T &'1.L ATIO AND IN ER-TIO UNTT, EW COAXI L (October, 1952)

D PTORS, e ... Co I L CCE SORIES (October, 1952) D PTORS, " NYVERSAL" COAXIAL (F bru ary, 1953)

AIR CunRE T MADE VISIBLE (January, 1953) MPLl1''18R JRCUIT, EW p SH-PULL ( . P. G.

Peterson: October, 1951) MPLJFlERS, M TIR GIJ: ILTER FOR AUDIO D

ULTRASON"IC (Hor atio W. Lamson: June, 1951) ANALYZER FOR orsE ME 1>EMENT8, A OcTAVE-

BANU ( . P. G. Peterson: September, 1951) AUDIO AND ULTRASONIC M'l:PLIFIERS, A MULTIRANGE

F1LTJ;;R FOR (Horatio W. Lam.son: June, 1951) AuTOTRANSFORMERS, PoRTAaLE TEST (R. F.

Bennington: March, 1953) AUTOTRANSFORhlERS--V AlUAC® WITH DURATRAK, A

EW STANDARD OF RELIABILITY I VARIABLE (G. Smiley, Ivan G. East.on: April, 1953)

BALUN, EW COAX I L AccE SORIES-(October, 1952) BASIS FOR FIELD CHECK.I 0 SOUND-METER CALIBRA­

TION, TH.E (W. R. Thurston: November, 1952) BRANCH PLANT, EW (December, 1952, and January,

1953) BRIDGE NO ITS ACCESSORIES, THE Cmnl-TuBE

(A. G. Bou quet: September, 1952) BruoGE DOUBLE AS LABORATORY STAND RD,

VERS TILE RESISTAN E LunT (W. M. Hague, Jr.: January, 1952)

BRIDGE FOR THE R.!t...PID TESTING OF COMPONENTS, A NEW CoMPArusoN (M. C. Holtje: December, 1952)

BRIDGE, A !-MEGACYCLE SCHER.ING (Ivan G. Easton:. February, 1952)

BRIDGE, TRANSISTOR MEASURE1'1:ENTS WITH THE VACUUM-TuaE (A. G. Bousquet: March, 1953)

C.tt..aLE CHARACTERISTICS, THE MEABUREME T OF (February, 1953)

CALJBR TION·CHECK ERVICE FOii. SOUND METER (W. R. Thurston: ovember, 1952)

CALIBR TIO , THE BAs1 FOR FIELD CHECK.I G SoUND­METER (W. R. Thurston: ovember, 1952)

CAPACIT CE BRIDGE, A GUARD CIRCUIT FOR THE (Ivan G. Easton: August, 1952)

CAPACIT CE ME URI G E 1BLY, TYPE 1610-(August, 1952)

Co I L AccEssoRIE - AoAPTOns, L1NE TRETCHER, COMPONENT MoUNT, BAL , TEnMI TION , AND INSERTION NIT, EW (October, 1952)

COAXIAL ADAPTORS, "UNIVERSAL" (Februar y, 1953) COAXIAL CONNECTORS FOR RG-58/U AND OTHER

CABLES (April, 1952) COMPARISON BIUDOE FOR THE RAPID TESTI G OF

COMPONENTS, A NEw (M. C. Holtje: December, 1952)

COMPONENT MOUNT, ·Ew Co.tt..XIAL AccE SORIES (October, 1952)

CONDENSER MICROPHONE SYSTEM, TYPE 1551-Pl (E. E. Gross, Jr.: May, 1953)

CONNECTOR (PART I), STANDA.IIDIZED TERMINALS AND (H. C. Littlejohn: June, 1952)

CONNECTORS (PART II), STANDARDIZED TERMINALS AND (H. C. Littlejohn: July, 1952)

CRYSTAL OSCILLATOR - A SI '[PLIFIED FREQUENCY STANDARD FOR THE SMALL LABORATORY, T HE NIT (Robert B. Richmond: February, 1952)

Cun.RENTS MADE VIsnu.E, AIR (January, 1953)

DECADE RESISTORS, THE NEW TYPE 1432 (Ivan G. Easton: June, 1951)

DELIYERY SCHE.oULES (Septem.ber, 1952)

DIELECTRIC MATERIALS, A SAMPLE HoLDEn FOR SOLID (Ivan G. Easton: ugust, 1951)

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s

DURATRAK, A EW STAND RD OF RELIABILITY I VARIABLE AUTOTRANSFORMERS-V ARIAC@ WITH (G. Smiley, Ivan G. Easton: April, 1953)

ELECTRICAL NOISE, A GENERATOR OF (A. P. G. Peterson: December, 1951)

ExP NDED REPAIR ER ICE ( pril, 1953) FIELD CHECKING SOUND- M ETER CALIBR.ATIO , THE

BAsrs FOR (W. . Thurston: ovember, 1952)

FILTER FOB UDIO AND LTJ:lA 0 '1'..PLI IER , MULTIR.ANGE (IIoratio W. Lamson: June, 1951)

FILTER, TYPE 1212-Pl H10H-PAss (February, 1953) FILTER, TYPE 1951-A (February, 1953)

500-VOLT MEGOHMME R F R I SULATlO TESTI G, ( . G. Bousquet: ovemb r, 1951)

FREQUENCY STANDARD FOR THE SMALL LABORATORY , THE NIT CRY TAL OsctLLATOR - SIMPLIFI o

(Robert B. Rfohmond: February, 1952)

GENERATOR OF ELECTRICAL OISE, A (A. P. G. Peterson: December, 195 )

GERMANIUM CRYSTAL D:JODES, 1-IARMONl:C GENERATION I THE U-H-F REGIO BY ME.ANS OF (Frank D. Lewis: July, 1951)

Goon CAUSE, (August, 1952) GRAPHIC RECORDER PLOTS LEVEL l EITHER POLAR. OR

LINEAR Cool\DINATES (January, 1952) GUARD CIRCUIT FOR THE CAPACITANCE BRIDGE, A

(Ivan G. Easton: August, 1952)

HANDBOOK OF NoISE MEASUREMENT (April, 1953)

HARMONIC GENERATION IN THE U-I-:1-F REGION B

MEANS OF GERMANIUM CRYSTAL DIODES (Frank D. Lewis: July, 1951)

HIGH- Ass FILTER, TYPE 1212-Pl (February, 1953)

HIGH-POWER TOROIDAL OuTPUT TRANSFORMER, A (Horatio W. Lamson: November, 1951)

INDUCTORS, A NEW SERIES OF STANDARD (Horatio W. Lamson: ovember, 1952)

I SERTJON UNIT, NEw CoA IAL AccEssoRIES -(October, 1952)

INSTRUCTION MA.Nu.AL FOR SLOTTED LINE, EW ( pril, 1953)

I SULATION TESTING, A 500- OLT MEGOHMMETER FOB (A. G. Bousquet: ovember, 951)

L:IMJ:T BRIDGE DOUBLES .AS LABORATORY STANDARD, VERSATILE RESISTANCE (W. M. IIague, Jr.: January, 1952)

LINE STRETCHER, EW COAXIAL ACCESSORIES -(October, 1952)

MEA UREMENT OF CABLE CHARACTE RISTICS, T:B"E (February, 1953)

MEASUREME T o TR.A SFOR En OrL, TES"' CELL FOR PowER FACTOR (January, 1953)

MEA UREMENTS WITH THE ACUUM-TUBE BRIDGE, TR.A srsTOR (A. G. ousquet: March, 1953)

MEGOH.cWMETER FOR I NSULATIO TEST G, A 500-VOLT (A. G. Bousquet: ovember, 1951)

METERS, A CALIBRATIO -CHECK SERV:JCE FOR SOUND (W. R. Thurston: ovember, 1952)

MICROPHONE SYSTEM, TYPE 1551-Pl CONDENSER (E. E. Gross, .Jr.: May, 1953)

MoRE USEFUL VARIAC CIRCUITS ( ove:mber, 1952) MULTIRANGE FILTER FOR AUDIO AND LTR.ASONIC

AMPLIFIERS, (Horatio W. Lamson : June, 1951)

EW BR.A CH PLA T (Dece ber, 1952 and January, 1953)

NEW COAXIAL ACCESSORIES - Ao.APTORS, LINE STRETCHER, COMPONENT MOUNT, BALUN, T RMIN -TlONS, AND INSERTION NIT (October, 1952)

NEw CoMPARiso BRIDGE FOR THE RAPID TESTl G o.F COMPONENTS, A (M. C. Holtje: De ember, 1952)

NEW INSTRUCTION MANUAL FOR SLOTTED LINE ( pril, 1953)

EW Pu u-PULL AMPLIFIER CIRCUIT, A (A. P. G. Peterson: October, 1951)

NEw SERIES OF STANDARD INDUCTORS, (IIoratio W. Lamson: November, 1952)

NEw STANDAl\D OF RELIABILITY IN VA.RIA.BLE Au-ro­TR.ANSFORMERS - VA.R.IAC® WITH DURA.TR.AK, (G. Smiley, Ivan G. Easton: April, 1953)

NEW 2-AMPERE VARIAC, A (G. Smiley: May, 1953)

SEPTEMBER, 1953

:rEW TYPE 1432 DECADE RESISTOBB, THE (I an G. Easton: .June, 1951)

NEW NIT INSTRUMENTS POWER. SUPPLIES -MODULATOR (.July, 1951)

EW NIT OscILLATOR - 50 to 250 Mc, G. Bousquet: January, 1953)

NoisE, A GENERATOR OF ELECTRICAL P. G_ eterson: December, 1951)

OJ E MEASUUEMENT, lIANDBOOK OF priJ, 1953)

OISE MEASURE1"£E S, AN CTAVE-BAND A ALYZER FOR (A. P. G. Peterson: September, 1951)

OISE, PULSED SIG ALB IN (June, 1952)

ULL DETECTOR, TYPE 1212-A UNIT (R. B. Richmond: February, 1953)

OCT.AVE-BAND ANALYZER FOR OISE MEAS REllfENTS, ( . P. G. Peterson: epte:mber, 1951)

OIL, TEST CELL FOR POWER F CTOR MEAS REME T'

ON TRANSFORMER (January, 1953) I-MEGACYCLE ScJ:IERING BnrnGE, A (I van G. Easton:

February, 1952)

OsCILLATOR - 50 to 250 Mc, A NEw NIT (A. G. Bousquet : January, 1953)

OUTPUT TRANSFORMER, A HIGH-POWER TOROIDAL (Horatio W. Lainson: November, 1951)

PORTABLE POWER DISTRIBUTION PANEL FOR TELE­VISION STUDIOS, A (.January, 1952)

PORTABLE TEST AUTOT.R.ANSFORME'RS (R. F. Bennington: March, 1953)

POWER DISTRIBUTIO PANEL FOR TELEVISIO STUDIOS, A PORTABLE (.January, 1952)

PoWER F .ACTon MEASUREMENTS ON TaAN FORMER 01 L,

TE '£ ELL FOR (January, 1953) PULSED SIG A.LS I OISE (June, 1952)

PusH-PULL AMPLIFIER CIRCUIT, A NEw ( . P. G. Peterson: October, 1951)

QUIET SHIP (September, 1952) RECORDER PLOTS LEVEL IN ErTUER POLAR OR LINEAR

COORDINATES (.January, 1952)

REP.AIRS RVICE TO WEST Co ST CusTOMERs, WESTER INSTRUMENT Co. OFFERS (May, 1952)

REPAu1 SERVICES, EXPANDED (April, 1953) REsISTA CE LIMIT BRIDGE DOUBLES AS LABORATORY

STANDARD, VERSATILE (W. M. Hague, .Jr.: .January, 1952)

RHEOSTAT BURNOUT ?, WHY (P. K. McElroy : August., 1951)

SAMPLE HOLDER FOR SoLrD DIEL � TRIC M TERIA.LS, (Ivan G. Easton : August, 1951)

CHE.lU .o BRIDGE, I-MEGACYCLE (Ivan G. Easton: February, 1952)

SEnV:JcE FOR SoUND METERS, A CALIBRATION-CHEr.K ( . R. Thurston: ovember, 1952)

SIG ALS IN OISE, PULSED (.June, 1952) IMPLE I-:IARMONIC Mono , V A.R.IAc® SP ED Co TROL

HELP TOD MO STRATE (January, 1953) Sr G LE-ENDED PusH-PULL AM:PLIFrER (see: ew Push­

Pull Amplifier Circuit, )

SLOTTED LINE, EW INSTRUCTION MANUAL FOR (April, 1953)

SoUND-L EL METER, TYPE 1551-A (E. E. Gross, Jr.: March, 1952)

OUND-METER C.ALIBR.ATIO • THE BASIS FOR FIE LD CHE KING (W. R. Thurston : November, 1952)

0 D METERS, A CALIBR.A'rlON-CHECK SERVICE FOH

(W. R. Thurston: :Tovember, 1952) SoUNo-SURVEY METER, THE (Arnold Peterson : April,

1952) SPEED CONTROL HELP TO DEMON TB.ATE St:MPLE

HARMONIC MonoN, V.ARIAc® (January, 1953)

TANDARD IND CTORS, A NEw SERIES OF (Horatio W. Lamson: ovember, 1952)

TANDA.BDIZED TERlllIINALS AND CONNECTORS (PA.BT I) (H. C. Littlejohn: June, 1952)

STANDARDIZED TERMINALS AND CoNNECTOBB (PART II) (H. C. Littlejohn: July, 1952)

TELEVISION STtJDil'IS, A PORTABLE POWER DISTRIBU­TION PANEL FOR (January, 1952)

TERMINALS AND CONNECTORS (PA.RT I), STANDARDIZED (H. C. Littlejohn: June, 1952)

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GENER AL R ADI O EXPERI MENTER

TERMINALS ANO CON ECTOJ\S (PART I), STANDARDIZED (H. C. Littlejohn: July, 1952)

TERMINATIONS, NEw COAXIAL AccEsso1uEs (Octob er, 1952)

TE T CELL FOR POWER FACTOl\ MEASUJ\EMENTS ON TRANSFORMEn OIL (January, 1953)

TE TING OF COMPONENTS, A NEW COMPARlSO BRIDGE FOR THE RAPTD (M. C. Holtje: December, 1952)

THREE-QUARTER HonSEPOWER VARTAC® MoTOR SPEED CoNTHOL, A (W. . Tuttle: May, 1952)

TonoJOAL OUTPUT Tn NSFORM"ER, A H1G11-PowER (Horatio W. Lam.son: November, 1951)

TRANSFORMER , A H IGH-POWE R TOROIDAL OUTPUT (Horatio W. Lamson: ovember, 1951)

TRANSISTOR MEASUREMENTS WTTH THE VACUUM-TUBE IlarnoE (A. G. Bousquet: March, 1953)

TWELVE TONS OF S LT AND A IMPEO CE BRIDGE DETE T LE R. IN PTPE LINE (June, 1952)

2-AMPERE VA1UAC. A NEw (G. Smiley: May, 1953)

TYPE 700-Pl VOLTAGE DIVTDER (December, 1951)

TYPE 1212-A NIT NULL DETECTOR ( Robert B. Richmond: February, 1953)

TYPE 1212-Pl H1on-PASS FrLTEl\ (February, 1953)

TYPE 1551-A SOUND-LEVEL METER (E. E. Gross, Jr. : March, 1952)

TYPE 1551-Pl C ONDENS ER MICROPHONE SYSTEM (E. E. Gross, Jr.: May, 1953)

TYPE 1610-A C APACITANCE MEASURING ASSEMBLY (August, 1952)

TYPE 1951-A FILTER (February, 1953)

-I:l-F REGION BY MEANS OF GERMANIUM CRYSTAL D10DES, 1IA1'1.MONIC GENERATION IN T HE (Frank D. Lewis: July, 1951)

LTRASONJC AMPLIFIERS, A MULTI RA GE FILTER FOR Auo10 ANO (Horatio W. Lamson : June, 1951)

UNrT CRYSTAL OsclLLATOR - A SrMPLil"IBD FRE­QUENCY STANDARD FOR THE Sl\U..LL LABORATORY, THE (Robert B. Richmond: February, 1952)

6

NIT IN Tl\UMENTS PowER SUPPLIES - MoouLATOl\, EW (Ju]y, 1951)

UNIT NuLL DETECTOR, TYPE 1212-A ( Robert B. Richmond: February, 1953)

NIT OscILLATOR - 50 to 250 Mc, A Ew (A. G. Bou quet: January, 1953)

" NIVERSAL" COAXIAL ADAPTOR (Februa ry , 1953)

USEFUL VARIAC CIRCUIT, A (August , 1952)

USES OF VARIACS IN ELECTl\ICAL ENGINEEJUNG POWER LABORATORIES (Abraha m Abramowitz: May, 1952)

VACUUM-TUBE BRIDGE AND ITs AccBssoruEs, THE (A. G. Bousquet: Sept ember, 1952)

VACUUM-TUBE Bl\IDGE, TRANSISTOR MEA.SUHEME T WITH THE (A. G. Bousquet: March, 1953)

VARIABLE AUTOTRANSFOl\MERS VARJAC@ WITH DURATRAK, NEW STJ\NnARO OF RELI ABILITY IN (G. Smil ey, Ivan G. Easton : April, 1953)

V ARIAC® CIRCUIT, A USEFUL (August, 1952)

VAnIAc® C1ncurT, A MORE USEFUL (November, 1952)

v ARIAC® MOTOR SPEED CONT ROL, A THREE-QUARTER HORSEPOWER (W. N. Tuuttle: l\llay, 1952)

VARIAC@, A EW 2-AMP EBE (G. Smiley : May, 1953)

V lUAC@ PEED CONTROL HELPS TO DEM ONSTRATE SIMPLE HAn 1omc MOTION (January, 1953)

VAruAc® WITH DunATl\AK, A NEw STAND ARD OF RELI ABILITY IN VARIABLE AUTOTRANSFOl\MERS (G. Smiley, Ivan G. Easton: April, 1953)

V Al\IACS IN ELECTl\ICAL ENGINEERING POWER LA:sORATORIES, USES OF (Abraham Abramowitz: May, 1952)

VEl\SATILE RESISTA CE LIMIT BnmGE DOUBLES AS LABORATORY STANDARD (W. M. Hague, Jr.: January, 1952)

VOLTAGE DIVIDER, TYPE 700-Pl (December, 1951) WESTERN INSTRUMENT COMPANY OFFERS REPAIR

SERVICE TO WEST COAST CUSTOMERS (May, 1952)

WHY RHEOSTAT BURNOUTS? (P. K. McElroy: August , 1951)

INDEX BY AUTHOR

ABR -'COWITZ, A.BR HAM

U es of Va riacs iD Electrical Engineering Power Laborato ries (May, 1952)

BENNINGTON, R. F. Portable Test Autotransformers (1\1arch, 1953)

BOUSQUET, A. G. 500-Volt Megohmmeter for I nsu lat ion Te ting

(November, 1951) A ew Unit OsciUator-50 to 250 Mc (January, 1953) Transistor Measurements with the Vacuum-Tube Bridge (March, 1953) The Vacuum-Tube Bridge and Its Accessories (September. 1952)

EASTON, IVAN G. Guard Circuit for the Capacitance Bridge (August,

1952) A New Standurd of Reliability in Variable Auto­transformers - aria with Duratrak (April, 1953) The ew Type 14:32 Decade Resist.ors (June, 1951) A I-Megacycle Sheri ng Bridge (February, 1952) A Sample Holder for Solid Dielectr ic Materials (August, 1951)

GROSS, JR., ERVIN E. Type 1551-A Sound-Level Meter (March, 1952) Type 1551-Pl Condenser Microphone System (May, 1953)

HAGUE. JR., w. M. Versatile Resistance Lim.it Bridge Doubles as Labo­ratory tandard (January, 1952)

HOLT.IE, M. C. A New Comparison Bridge for the Rapid Testing of Components (December, 1952)

LAMSON, IIORATIO W. A High-Power Toroidal Output Transformer (No­v emb er, 1951) A Mu lti range Filter for Audfo and Ultrasonic Ampli­fiers (JunA, 1951) A New Seri!'!>< of8t.nndard Inductors (November, 1952)

LEWIS. FnANK D. Harmonic General ion in the U-H-F Region by M eans of Germanium Crystal Diodes (July, 1951)

LITTLEJOHN, H. c. Standardized Terminals and Connectors (Part I) (June, 1952) Standardized Terminals and Connectors (Part II) (July. 1952)

:vic:ELHOY, P. IC. Why Rheostat Burnoutsi> (August, 1951)

PETERSON, A. P. G. A Generator of Electrica l Noise (December, 1951) A New Push-Pu ll Amplifier Circuit (October, 1951) An O ctave-Ban d Analyzer for Noise Measurements (September, 1951) The Sound-Survey Meter (April, 1952)

s�uLEY, G. A ew Standard of Reliability in Variable Auto­transformer s - Variac® with Duratrak (April, 1953) A ew 2-Ampere Varinc (April, 1953)

RICHMOND, ROBERT Il. Type 1212-A Unit Null Detector (February, 1953) The UDit Crystal Oscillator - A Simplified Fre­quency Standard for the Small Laboratory (February, 1952)

THURSTON, w. R. The Basis for Field Checking Sound-Meter Calibra­tion (November, 1952) A Calihration-Check Service for Sound Meters (November, 1952)

T TTLE, w. N. Three-Quarter Horsepower Variac@ Motor Speed

Control (May, 1952)

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7 SEPTEMBER, 1953

INDEX BY INSTRUMENT TYPE NUMBER

TYPE V-2 VARIAC A New 2- Ampere Variac (G. Smiley : May, 1953)

TYPE V-20H M v ARIAC Portable Test Autotransformers (R. F. Bennington: March, 1953)

TYPE 200-B V ARIAC A ew 2-Ampere Variac (G. Smiley: May, 1953)

TYPE 214 R:s:EO TAT Why Rheostat Burnouts? (P. K. McE lro : August, 1951)

TYPE 27 4 CONNECTORS Standardized Terminals and Connectors (Part I) (H. C. Lil tlejoh.n: June, 19 52) Standardized Terminals and Connectors (Part 11) (H. C. Litt lej ohn: July, 1952)

TYPE 561-D VACUUM-TUBE BRIDGE The Vacuu:m-Tube Bridge and Its Accessories (A. G. Bousquet: September, 1952) Transistor Measurements with the Vacuum-Tuhe Bri dge (A. G. Bousquet: March , 1953)

TYPE 650-A IMPEDANCE BRIDGE Twelve Tons of Salt and an Impedance Bridge Detect Leak in Pipe Line (June, 1952)

TYP.E 700-Pl VOLTAGE DIVIDER Type 700-Pl Voltage Divider (December, 1951)

TYPE 716-CSl CAPACITANCE BRIDGE A 1-Megacycle Schering Bridge (Ivan G. Easton: February, 1952)

TYPE 716-P4 GUARD CIRCUIT A Guard Circuit for the Capacitance Bridg (Ivan G. Eas·tou: August, 1952)

TYPE 740-BG CAPACITANCE TEST B1UDGE Test Cell ror Power Factor Measurements on Trans­former Oil ( J anuary , 1953)

TYPE 759 SOUND- LEVEL METER The Basis for Field Checking Sound-Meter Calibra­tion (W. R. Thurston : November, 1952)

TYPE 838 CONNECTORS TYPE 838- K TEST LEAD KIT

Standardized Terminals and Connectors (Part II) (H. C. Littlejohn: July, 1952)

TYPE 87 4 ADAPTORS New Coaxial Accessories - Adaptors, Line Str tcher, Component Mount, Balun, Terminations, and In­sertion Unit (October, 1952) "Universal" Coaxial Adaptors ( February, 1953)

TYPE 874 CONNECTORS Standardized Terminals and Connectors (Part I) (H. C. Littlejohn: June, 1952) Standardized Terminals and Connectors (ParL fl) (H. C. Littlejohn: July, 1952) New Coaxial Accessories (October, 1952)

TYPE 874 TERAnNATIONS

TYPE 874-LK CONSTANT-IMPEDANCE AnJU TABLE LrNE

TYPE 874-M COMPONENT MOUNT

TYPE 874-UB BALUN TYPE 874-X INSERTION NIT

New Coaxial Accessories (October, 1952)

TYPE 874-LB SLOTTED LINE New Instruction Manual for Slotted Line (April, 1953)

TYPE 938 BINDING PosTs Standardized Terminals and Connectors (Part I) (H. C. Littlejohn: June, 1952)

Standardized Terminals and Connectors (Part II) (H. C. Li ttlejohn: July, 1952)

TYPE 938 CONNECTOR Standardized Terminals and Connectors (Part II) (H. C. Littlejohn: July, 1952)

TYPE 942-A OUTPUT TRANSFORMER A High-Power Toroidal Output Transformer (Horatio W. Lamson: ovember, 1951) A New Push - Pull Amplifier Circuit (A. P. G. Peterson: October, 1951)

TYPE 1203-A U IT Powi;;n SUPPLY ew Unit Instruments Power Supplies - Modulator

(July, 1951)

TYPE 120,t-B UNIT VAJ.UABLE PowEu SUPPLY New Unit Instruments Power Supplies - Modulator (July, 1951)

TYPE 1209-A UNTT OSCILLATOR Harmonic Genera Lion in the -H-F Regio n hy l\1eans of Germanium Crystal Diodns (Frank lJ. Lewis: July, 1951)

YPE 1212- UNIT LL DETE TO.R

Type 1212-A nit Null Detector (R. B. Richmond: February, 1953)

TYPE 1212-Pl HIGH-PA. FILTEll Type 1212-Pl High-Pass Filter ( ebruar-y, 1953)

TYPE 1213-A UNIT CRYSTAL 0 CILLATOH The Unit Crystal Oscillator - A Simplified Fn'­quency Stand ard for the Small Laboratory (February 1952)

TYPE 1214-A UNIT OscILL TOR ew a.it Instruments Po wer upplies - Modulator

(July, 1951) TYPE 1215-A NIT O SCILLATOR

A New Unit Oscillator - 50 to 250 Mc (A. G. Bousquet : January, 1953)

TYPE 1231-P5 ADJ USTA.BLE FILTER A Mul tiran�e .Filter for Audio and ltrasonic Ampli­fiers (Horatio W. Lamson: June, 1951)

TYPE 1262-A POWER SUPPLY Type 551- Sound- evel Meter (E. E. Gross, Jr.: March, 1952)

TYPE 1304-A IlEAT-FaEQUENCY OSCILLATOR Graphic Hecorder Plots Level in Either Polar or Linear Coordinates (January, 1952)

TYPE 1390-A HANDOM-NOTSE GENERATOR A Generator of Electrical Noise (A. P. G. Peterson: December, 1951) Pulsed Signals in oise (June, 1952)

TYPE 1432 DECADE RE I TOR The ew Type 1 32 Decade R sistors (Ivan G. Easton: Ju.ne, 1951)

TYPE 1482 INDUCTORS A New Series of S tandard Inductors (Ilora-tio W. Lamson: No vember, 1952)

TYPE 1532-B STROBOLUME Air Currents Made Visible (January, 1953)

TYPE 1550-A OCTAVE- BAND NOISE ANALYZER An Octave- Band Analyzer for Noise l\1easurements (A. P. G. Peterson: September, 1951)

TYPE 1551-A SOUND LEVEL METEB Type 1551-A Sound-Level Meter (March, 1952) The Rasis for Field Checking Sound-Meter Calibra­tion (W. R. Thu.rston: November, 1952)

TYPE 1551-Pl CONDE EL"l MJCHOPBONE SY TE tl

Type 1551-Pl Condenser Micrcwhoue System (E. E. Gross, Jr.: May, 1953)

TYPE 1552-A So· NO-LEVEL CALI.Bu Ton A Calibration-Ch ck Service for Sound Meters (\V. R. Thurston : ovember, 1952) The Basis for Field Checking Sound-Meter Calibra ·

tion (W. R. Thurston: ovember, 1952) TYPE 1555-A SOUND-SURVEY METER

The Sound-Survey Meter ( pril, 1952) Quiet Ship (September, 1952)

Calibration-Check ervice for ound Meters (W. R. Thurston : ovember, 1952)

YPE 1604-A COMPARISON BRIDGE A New Comparison Bridge for the R apid Testing of Components (M. C. Hollje: December, 1952)

TYPE 1610-A CAPACITA CE MEASURING ASSEMBLY Type 1610- Capacitance easuring ssembly (August, 1952)

TYPE 1652- RE t: T CE LIMl'l' BRIDGE er-satile Resist.an e Limit.. Br.id�e Double as Labo­

ratory Standard (January, 1952)

TYPE 1690-A DrELE TRIC SAMPLE HoLDEn TYPE 1690-P2 ADAPTOn AssEMBLY

Sample Holder for Solid Dielectric Materials (Ivan G. Easton: August, 1951)

YPE 1 702-A V ARIAC@ SPEED CONTROL A Th ree-Quarter H orsepower ariac Motor Speed Control (W. . Tultle: May, 1952)

TYPE 1862-A MEGOffM:M.ETER A 500-Vol.t Mego hmmeter for Insulation Testing (A. G. B ousquet : ovember , 1951)

TYPE 1951-A FILTER Type 1951-A Filter (February, 1953)

www.americanradiohistory.com

GENER AL R ADI O E X PERIM E NTER 8

G E N E R A L R A D I O AT N . E . C . 1 9 5 3 General R adio products will be on

display in Booths 87 and 88 at the National Electronics Conference to be

held in he Hotel Sherman, Chicago,

September 28, 29, and 30. Among the General Radio instru­

ments shown will be : Type 1 21 7-A Unit Pulse Generator -

a small, compact, inexpensive generator

of pulses, with rise time as short as 0 .05 microsecond and repetition rates be­

tween 30 and 100,000 cps. Type 1 000-P7 Balanced Modulator -

a orystal-diode modulator designed to operate on the output of standard-signal generators to produce 100% amplitude

modulation without incidental fre­quency modulation . Carrier frequency

range is 60 to 2500 megacycles, and

modulating frequencies up to 20 mega­

cycles can be used . Pulse modulation

can also be applied, with rise times as

short as 0.02 microsecond. Limit bridges for measu ring d-c re­

si tance and for comparing re i or ,

capacitors, and inductors at au dio-fre­

quencies. Sound-measuring equipment - a com­

plete line of sound-level meters, ana­

lyzers, and accessories for the measure­

ment of noise and other sounds. Type 1 602-B U-H-F Admittance Meter,

with a full line of accessories, set up to m@asure television transmitting an­tennas.

Variac® autotransformers with G eneral

Radio's new Duratrak contact surface that stands up under punishing over­

loads - an outstanding development

that makes the variable autotrans­former as durable as a fixed-ratio

transformer.

THE General Radio EXPERIMENTER is mailed w i t ho u t charge eac h

mon t h t o engineers, scien tis ts, technicians, and o t hers in teres ted

in comm unica tion-frequency meas ure men t and con trol prob lems . Wh en sending req uests for s u bscrip t ions and a ddress- change notices ,

please s upply t h e following informa t ion : na me, company a ddress, type of b us iness company is engaged in, and t i tle or posi tion of indi vidual.

G E N E R A L R A D I O C O M P A N Y 2 7 5 M A S S A C H U S E T T S A V E N U E

C A M B R I D G E 3 9 M A S S A C H U S E T T S T E L E P H 0 N E : T R owbridge 6 • 4 4 0 0

B R A N C H E N G I N E E R I N G O F F I C E S

N E W Y O R K 6 , N E W Y O R K

9 0 W E S T S T R E E T

T E L . - W O r t h 2 - 5 8 3 7

L O S A N G E L E S 3 8 , C A L I F O R N I A

1 0 0 0 N O R T H S E W A R D S T R E E T

T E L - H O i i y w o o d 9 - 6 2 0 1

C H I C A G O 5 , I L L I N OIS 9 2 0 S O U T H M I C H I G A N A V E N U E

T E L. - W A b a s h 2 · 3 8 2 0

R E P A I R S E R V I C E S

W E S T C O A S T W E S T E R N I N S T R U M E N T C O .

8 2 6 N O R T H V I C T O R Y B O U L E V A R D

B U R B A N K , C A L I F O R N I A

T E L . - R O c k w e l l 9 - 3 0 1 3

C A N A D A B A H Y E N G I N E E R I N G , LT D .

5 F I R S T S T R E E T A J A X , O N T A R I 0

T E L - T o r o n t o W A - 6 8 6 6

]

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