GENERAL RADIO COMPANY 1231-B Operating Instructions Manual Download Page 1 | Manualshive

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Summary of Contents for 1231-B

Page 1: ...OPERATING INSTRUCTIONS TYPE 1231 B AMPLIFIER AND NULL DETECTOR GENERAL RADIO COMPANY ...

Page 2: ...OPERATING INSTRUCTIONS TYPE 1231 B AMPLIFIER AND NULL DETECTOR Form 634 H May 1961 GENERAL RADIO COMPANY WEST CONCORD MASSACHUSETTS USA ...

Page 3: ...lay Rack Model 5 Section 4 OPERATING PROCEDURE 6 4 1 General 6 4 2 Use as an Amplifier 6 4 3 Use as a Null Detector 6 4 4 Operation as Standing Wave Indicator 6 4 4 1 Frequency Selection 6 4 4 2 Test for Adequate R F Input for Low VSWR Measurement Assuming 50 Modulation 7 4 4 3 Measuring Standing Wave Ratio 7 Section 5 ACCESSORIES 7 5 1 Tuned Circuits 7 5 2 Adjustable Attenuator 9 5 3 Adjustable F...

Page 4: ...ons Height 8 in width 12 1 4 in depth 10 3 4 in over all Weight 23 3 4 pounds including batteries cabinet model TYPES 1231 P2 AND P3 TUNED CIRCUITS Tuning Accuracy 2 at normal voltage levels Attenuation At least 25 db to second harmonic Dimensions Height 4 1 8 in width 3 9 16 in depth 4 in over all Weight 3 7 8 pounds TYPE 1231 P4 ADJUSTABLE ATTENUATOR Source Impedance 30 kfl about equal to output...

Page 5: ...ding upon ftoquoncy Soeond hormonic rojoction 28 to46 db Termlnols Shielded cord and plug for connection to Typo 1231 6 jock top terminals for external capacitors Acceuorln Available Type 219 Decode Copoeitou for tuning filter betwoon frequencies provided Dimensions Front Panel height 7 in width 6 1 8 in Cabinet depth 9 3 4 in Internal shiold box hoight 6 1 A in width 4 1 2 in depth 9 in W lght 9 ...

Page 6: ...scopes 1 2 DESCRIPTION 1 2 1 GENERAL The Type1231 BAmplifierand Null Detector is avail able in cabinet and relay rack models operated by either a battery Burgess 6TA60 Army Signal Corps BA48 or an a c power supply Type 1261 A Power Supply Type numbers used todesignatethevarious mod els are indicated below 1231 BM Cabinet model battery operated 1231 BMA Cabinet model a c operated 1231 BR Relay rack...

Page 7: ...function DETECTOR as a logarithmic amplifier for null detector operation BATT CHECK Push buttons 2 Check condition of the plate and filament batteries OFF Push button Turns off battery power supply INPUT Push buttons 2 0 03 v sets approximate maximum no load gain at 85 decibels with maximum input voltage of less than 0 03 volt 1 v sets approximate maximum no load gain at 55 decibels with maximum i...

Page 8: ...ified circuit diagram Figure 7 shows that the amplifier has three stages and a built in vacuum tube voltmeter which consists of a diode rectifier a d e amplifier and the panel meter 2 2 LINEAR AMPLIFIER During linear amplifier operation there is a choice of maximum no load gain of 55 or 85 decibels as selected by the input attenuator buttons at 1 volt or 0 03 volt respectively A tapered wire wound...

Page 9: ...um If the crystal is operating in the square law region the actual decibel difference in r f voltage is half the decibel difference measured by the attenuator or meter 2 5 FREQUENCY RESPONSE The maximum open circuit voltage gain is over 70 decibels at 10 cycles over 45 decibels at 100 kilocycles and greater than 83 decibels at midband The frequency characteristic is shown in Figure 2 0 I lll 10 20...

Page 10: ...ly and again note the meter reading Tum the screw driver adjustment on top of the power supply until both meter readings are equal To keep the hum level low do not ground the case of the power supply to the instrument shield 3 3 RELAY RACK MODEL The Type 1231 P7 Connecting Panel is in stalled to fit the standard 19 ln relay rack When the Type 1231 PSAd justable Filter is included the Type 1231 P6 ...

Page 11: ...E AS AN AMPLIFIER For ordinary use operate with the NORM button pushed then meter deflection is approximately linear and full scale corresponds to 20 volts When the input voltage is too low to give satisfactory meter indications operate with the SENS button pushed The meter deflection is approximately linear and full scale corresponds to 2 volts 4 3 USE AS A NULL DETECTOR When using the Type 1231 ...

Page 12: ...enuation and the ampli fier meter reading b At the voltage minimum vary the attenuation of the Type 1231 P4 Attenuator until the amplifier meter reading is the same as that noted in step a c If the crystal is operating in the linear region the difference in attenuation at these two points is the standing wave ratio SWR 20 E log10 Em x expressed in decibels m1n d If the crystal is operating in the ...

Page 13: ...ES PER SECOND FigureS Attenuat ion Curve Types 123 1 P2 and P3 Tunod Circuits enough voltage level along the amplifying chain to withstand effects of external fields Figure 5 shows the attenuation vs frequency for the Types 123l P2 and P3 TUned Circuits 5 2 ADJUSTABLE ATIENUATOR When used with the Typel231 B am pllfier and Null Detector and the Type 874 LBA Slotted Line to measure standing wave ra...

Page 14: ...current The Adjustable Filter can be set toany one of 11 frequencies 50 I00 200 and 500 cycles and 1 2 5 10 20 50 and 100 kc In order to obtain high selectivity with low lnsenlon loss our sepsrate Inductors are used L1 20 henrys for 50 and 100 cycles centrlcore L2 2 henrys for 200 and 500 cycles duet core L3 300 millihenrys for 1 2 and 5 kc dust core L4 IS millihenrys for 10 20 50 and 100 kc dust ...

Page 15: ... At Capacitance Jf 50 c 20 c 50 c 0 to 2 66 100c 50 c 100 c 0 to 0 381 200 c 100 c 200 c 0 to 0 951 500 c 200 c 500 c 0 to 0 266 1 kc 500 c 1 kc 0 to 0 238 2 kc 1 kc 2 kc 0 to 0 0634 5 kc 2 kc 5kc 0 to 0 0177 10 kc 5 kc 10 kc 0 to 0 0507 20 kc 10 kc 20 kc 0 to 0 0127 50 kc 20kc 50 kc 0 to 0 00354 100 kc 50 kc 100 kc 0 to 0 00051 Typical low level characteristics of the Type 1231 P5 Filter when use...

Page 16: ...2 i 28 0 24 c 0 20 I iv 1 z 0 i 8 0 4 8 ffi 12 g 16 20 I I LI I L2 v I I v I v v L I I I I _ L3 i L4 I 02 05 0 1 0 2 0 5 I 2 5 10 20 00 100 1 L2 RESONANT FREQl NCY KILOCYCLES v 3 L4 Figure 7b Second Harmonic Discrimination Type 1231 PS Filter 02 05 10 20 50 I 2 5 10 20 50 100 RESONANT FREQUENCY KILOC ICLES 11 ...

Page 17: ...l and slide the instrument out of the cabinet 6 3 TUBE VOLTAGES AND RESISTANCE MEASUREMENTS Table 2 gives the normal d e voltages and d e resistances from various tube socket pins to ground A deviation of 10 percent from any of these val ues is not necessarily abnormal 6 4 ZERO COINCIDENCE If either the battery V3 V4 or the Type 1N56 A diode is replaced or as the battery ages the ZERO COINCI DENCE...

Page 18: ...eter TABLE 2 TEST VOLTAGES AND RESISTANCES TUBE TYPE V1 1U4 V2 1U4 V3 1U4 V4 1U4 NOTES Batteries A 1 5 v B 90v PIN 1 2 3 6 7 1 2 3 6 7 1 2 3 6 7 1 2 3 6 7 No batteries for resis tance measurements Panel controls and switch settings GAIN 0 VOLTS RESISTANCE TO GROUND TO GROUND 0 38 37 0 1 5 0 42 5 26 0 1 5 0 53 90 1 1 1 5 0 90 90 1 1 1 5 0 160 k 350 k 30 k 3 5 0 660 k 2 3 M 0 3 5 0 50 k 0 2 2 M 3 5 ...

Page 19: ...7 M 5 1 2 w REC 20BF Rl5 47 M 10 1 2 w REC 20BF Rl6 4 7 M 10 1 2 w REC 20BF Rl7 50 k POSC 11 Rl8 l SM 5 1 2 w REC 20BF Rl9 50 POSC 11 R20 9 1 k 1 1 2 w REF 70 R21 680 k 1 1 2 w REF 70 R22 Sk 5 973 410 R23 1 k 5 1 2 w REC 20BF R24 4 7 k 10 1 2 w REC 20BF R25 12 k 5 1 2 w REC 20BF R26 82 k 5 1 2 w REC 20BF R27 47 M 5 1 2 w REC 20BF R28 47 M 5 1 2 w REC 20BF R29 2 7 10 1 2 w REW 3C CAPACITORS All cap...

Page 20: ...SCELLANEOUS BATTERY Burgess 6TA60 Bl BATTERY 1 1 2 v 2BAC 4 Dl DIODE 1NS6 A Jl JACK CDSJ 820 Ml METER 200 f la MEDS 36 PLl PLUG CDMP 1344 Sl SWITCH SWPM 14 S2 SWITCH SWT 33SNP Vl TUBE 1U4 V2 TUBE 1U4 V3 TUBE 1U4 V4 TUBE 1U4 vs REGULATOR NE 2 NOTES A Type designations for resistors and capacitors are as follows COE Capacitor electrolytic COL Capacitor oil COM Capacitor mica COW Capacitor wax POSC P...

Page 21: ...C 1 04 7 INPUT t OIL 003v R 20 9 k C 4 25 TYPE 1231 B AMPLIFIER R 24 4 lk R 25 12k 105R FIL CHECK PL BATT Figure 8 Sche ...

Page 22: ... R 24 4 7k R 25 12k R 8 lOOk OFF 05 IU4 3 NULL DET f C 10 01 J 1 N56A cw R 19 50k SENS METER NORM METER DB AMPL 20v NOTE RESISTANCES IN OHMS UNLESS OTHERWISE SP CIFIEO Schematic Diagram k IOOO OHMS M I MEGOHM CAPACITANCES IN MICROFARADS UNLESS OTHERWISE SPECIFIEO p J1 f MICROMICROFARAOS 15 ...

Page 23: ... 0 v Figure 9 Elementary Schematic Diagram Includes Tube Layout AMPLIFIER r t RECTlAER 1 _ UTPUT m z m 0 0 c 0 i z ...

Page 24: ...R 7 560k R 24 4 7k R 25 B 1 R 21 680k I OFF Figure E Schematic Diagram ALTER C 12 V 4 v 3 lU4 R 17 50k 2 NULL DET 2 IU4 R27 R28 4l M 47M C 14 R 19 50k 710R SENS METER NORM METER DB AMPL 20v C 11 0 1 8 OUTPUT VIEWEO FROM PIN SlOE PL 1 NOTE RESISTANCES IN OHMS UNLESS OTHERWISE SPECIFIED k IOOO OHMS M I MEGOHM CAPACITANCES IN MICROFARADS UNLESS OTHERWISE SPECIFIED p p f MICROMICROFARADS 15 ...

Page 25: ...A lor Allor C il f l p WH t dtll UJ CANADA 9 9 floral Totonto I S Ot r h l p o CH rrr 6 l17r REPAIR SERVICES EAST CO AST C tt rnl Rod Co po r Deport ao A w COI ICCM d Mou fele11 o11 lM t oM 9 4iCO N E W Y O RK Celtefol lofl o Co 1 s o l tHd A ol il tt e t l iflttlttld H Ttl p on N 1 WOrth 4 1712 N J WHltl l tll140 Ml DWIST ol a1 1tllo Componr Stt 1 0fPUffmtnl 660S W al NOt llrt Ant Oolc ftort Ill ...

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