BC-222_SCR-194_SCR-195_user_1938.pdf

. L INSTRUCTION BOOK FOR RADIO SET SCR,-194 RADIO SET SCR-195 RESTRICTED Notice:-This document contains information affecting the national defense of the United States within the meaning of the Espionage Act (U.s.c. 50: 31, 32). The transmission of this document or the revelation of its contents in any manner to any unauthorized person is prohibited. The information contained in documents marked RESTRICTED will not be communicated to the public or to the press, but it may be communicated to any person known to be in the service of the United States. and to persons of undoubted loyalty and discretion who are cooperating in governmental work (AR 3305). PUBLISHED BY AUTHORITY OF THE CHIEF SIGNAL OFFICER ORDER 10. 1614J-NY.J8 DATED APRIL 12. I9U 2500 (11-15-38) INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 . coNitNTS SECTION I. -DESCRIPTION General. . . . . . . . . . . , . . . . List of Equipment-Radio Set SCR.194 . . . . . List of Equipment-Radio Set SCR.195 . . . . . . . . . . . . . . . . Radio Receivers and Transmitters BC222 and BC322 . . Antennas AN-29 and AN-30 . Mast Sections MS-49, 15-50, and MS-51. Box BX-l3 . Adapter SO-52 . . SECTION Il.-OPERATION Location and Selection of Frequency . . . . . Transmitting and Receiving . . . . , . Adjutment of Calibration . . . . . . . . _ . . . . . . . . . Operating Technique . . . . . . . . Portable Operation . Vehicular Operation. SECTION IlL-FUNCTION OF PARTS Radio Receiver and Transmitter BC222 . . Radio Receiver and Transmitter BC-322. SECTION IV.-MAINTENANCE Service . . . . . . . . . . Storage . SECTION V.-5UPPLEfo.IENTARY DATA Table I-Radio Receiver and Transmitter BC-222-Frequencies and Dial Readings Par. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Page 3 5 6 7 8 9 9 10 10 10 11 11 12 13 13 18 18 19 using scale with SOO-kc subdivisions. . . . . . . . . . . . . 19 19 Table II-Radio Receiver and Transmitter BC-222-Frequencies and Dia! Read- ings using scale with 400-kc subdivisions . . . . . . 20 20 Table III-Radio Receiver and Transmitter BC322-Frequencies and Dial Read- ings using scale with SOO-kc subdivisions . . . . . . . . . . . . . . . . . . 21 20 Table IV-Radio Receiver and Transmitter BC-322-Frequencies and Dial Read- ings using scale with 400-kc subdivisions . . . . . . . . . . . 22 20 Table V-List of Items-Radio Sets SCR-194 and SCR-195. . . . . . . 23 20 iii INSTRUCTION BOOK FOR RADIO SETS SCR194 AND SCR.195 ILLUSTRATIONS Figure I-Radio Set SCR-194, Components (except Chest CH-33) . . . Figure 2-Radio Set SCR-195. Components (except Chest CH-33) . . . Page I 2 Figure 3-Radio Receiver and Transmitter BC-222 (or 8C-322), External View showing carrying and battery straps and antenna mounting (on top of case). . . 3 Figure 4-Radio Receiver and Transmitter Be-222, with front cover removed showing dial with 500-kc sulxlivisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 5-Radio Receiver and Transmitter 8C-222, Icft side of chassis . . Figure 6-Radio Receiver and Transmitter 8C-222, right side of chassis. Figure 7-Radio Receiver and Transmitter 8C-222, case only, showing position of alternate 4 5 coil and location of antenna trimmer capacitor on under side of raised cover. 6 Figure 8-Radio Receiver and Transmitter BC-222, under side of chassis showing plug which fits into socket on Battery BA32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 9-Radio Receiver and Transmitter BC-322, with front cover removed. 1 Figure to-Radio Receiver and Transmitter BC-322, left side of chassis. 8 Figure II-Radio Receiver and Transmitter BC-322, right side of chassis. 8 Figure 12-Chest CH-33, showing interior. . . . . . . . . . . . 9 Figure 13-Box BX-13. . . . . . . . . . . . 9 Figure I4-Adapter SO-52 . . . . . . . . . . . . . . . Figure IS-Bag BG-H. Figure 16-Headset HS22A. Figure 17-Microphone T-24A . . Figure IS-Handset TS-II-A . Figure 19-Radio Receiver and Transmitter BC-222-Schematic Diagram. Figure 20-Radio Receiver and Transmitter BC-322-Schematic Diagram. Figure 21-Functional Diagram-Transmission Figure 22-Functional Diagram-Reception . . v to 12 13 14 14 15 16 17 18 co-,:,/S - VTt 67 , , -RADIO REC.e:IVER AND TRAN$MITTER ac 221 -=-.,. MA$T SECTIONS MS-+J-O 65) ADSET HS-21.A OCL . Figure I-Radio Set SCR-194, Components (except Chest eH-B), - Q o Z to 8 ;: Cl s; tJ - o en en n : - Z tJ en n : - 0, ; . -y; N SAC, 8; 6 :;: tJ o C/ :l C/ C/ () ? - :f : z tJ <n () ? - INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 INSTRUCTION BOOK FOR RADIO SET SCR-194 RADIO SET SCR-195 SEGrION I DESCRIPTION Par. 1 I. General.-Radio Sets SCR-194 and SCR t 95 are designed to provide means of voice com munication over relatively short distances. nominally up to 5 miles. All equipment required for transmission and reception is carried on the back of the operator in a canvas bag. This consists of the Radio Receiver and Transmitter 8C-212 (or 8C-322) contammg two tubes, the Baqery BA-32, an Antenna AN-29 (or AN-30), and a Headset HS-22 with a Microphone T-24 (or 2 Handsets TS-ll and Adapter SO-52). For vehicular operation, steel mast sections and a mast base are provided. These articles together with spares, are carried in a Chest CH-33. Figure J-Radio Receiver and Transmitter 8C-222 (or 8C-322), External View showing carrying and battery straps and antenna mounting (on top of case), 3 Par. 1 -INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 L Figure 4-Radio Receiver and Transmitter BC-222. with front cover removed showing dial with 500-kc subdivisions. Figure 5-Radio Receiver and Transmitter BC-222, left side of chassis 4 INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 Par. 2 2. List of Equipment-Radio Set SCR 194.- a. Fqr Pfff/(Jble USI Only-Carrid in Bag BG-71. Quantily Nomendmure t Antenna AN29 . . 1 Bag BG7l . . . I Battery BA32. 1 Headset HS-22 . . Weight in PQunds 0.50 2.50 12.00 .40 Microphone T24. 1.50 Radio Receiver and Transmitter Ben2. 8.00 TubeVT-J3. . .10 1 Tube VT-67. . . . . . .10 Total . . . . 25.10 b. Auxiliary Equipment-Carried in Chest eH-33. Quantity NOlnendo./ure I Antenna AN-29 (spare). 2 Battery BA-32 (spare). 2 Binding Post TM176. 1 Box aX-IJ . . Chet5t CH-JJ . . Cord CD-19S . . Weight in Pounds .50 24.00 . 1.60 28.50 .80 2 Innruc:tion Book for Radio Sets SCR-194 and SCR-195. . .60 Mast Base MP22 . . 6.50 Quantity Nomenclature Weight ill Pounds 2 Mast Section MS-49 . . . . . . . . . . . . . . 2 Mast Section MS-50 . . 2 Mast Section MS-51 . . 2 Tube Vf -JJ (spare) . . 2 Tube Vf-67 (spare) . . 25 ft. Wire -126 (or W-9) . . . . . . . . . . . . . . . . . . . . Total. .24 .50 1.00 .20 .20 .30 64.98 The only operating difference between the SCR-194 and SCR-195 sets is in frequency range; the SCR-194 covers the 27.7 to 52.2 megacycle_ band, while the SCR.195 covers the 52.8 to 65.8 megacycle band. The former includes Radio Receiver and Transmitter BC-222 and the latter includes Radio Receiver and Transmitter BC- 322. The general design, construction, and oper ation are otherwise identical. The frequency band in the BC-222 is covered by two interchangeable coils, while that in the BC322 is covered by a single coil. Two Handsets TS-l1 are provided in the Radio Set SCR-195, whereas Radio Set SCR-194 is provided with l!icrophone T24 and Headset HS-22. Figure 6-RadlO Receiver and Transmitter BC-222, right .ide of chassi . 5 Par. J INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 3. List of Equipment-Radio Set SCR 195.- a. For Porlabk US OnJy-Carried in Bag BG-71. Quantity Nomendature 1 Adapter 5052. , . AntennaAN30. Bag BG-71. . . . Battery BA-32. 2 Handset TS-l1 . . . . . . . . . . . , Radio Receiver and Transmitter BC322. 1 Tube VT -33. Tube VT67 . . . . . . . . Total. WeiglU in Pounds .65 .50 2.50 12.00 3.00 8.00 .10 .10 26.85 b. Auxiliary Equipment-Carried in Chat CHJJ. Quantity Nomenclature Weight in Pounds Antenna AN30 (spare). 2 Battery BAJ2 (spare) . 2 Binding Post TM176 1 Box BX13. . . . 1 Chest CH-33. 1 CordCD195. 2 Instruction Book for Radio Sets SCR.194 and SCR195. . . . . . . Mast Base MP22. 2 Mast Section MS-SO . . . . . . . . . . . . . . . . 2 Mast Section MS51. 2 Tube VT33 (spare). , . 2 Tube VT67 (spare). 25 ft. Wire W126 (or W9) . . . . . . . . . .50 24.00 .04 1.60 28.50 . 80 .60 6.50 .50 1.00 .20 .20 .30 Total. . . . . . . . 64.74 .sCL-77 . Figure 7-Radio Receiver and Tran5mitter BC222, case only, showing position of alternate coil and location of antenna trimmer capacitor on under side of raised cover. 6 INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 Par. 4 4. Radio Receivers and Transmitters BC- 222 and BC-322.-See Figures 3 to 11. All elements of the receiver and transmitter are chassis mounted and contained in an aluminum alloy case . This unit is designed to fit directly on top of the battery from which it derives its power. The case is fitted with a carrying strap, an antenna mounting, and two straps serving to hold the battery in place. Connection to the battery is effected through a plug in the bottom of the chassis and a socket in the top of the battery. Access to the top of the chassis may be Figure 8-Radio Receiver and Transmitter BC-222, under side of chassis showing plug which fits into !lOCket on Battery !lA-32. Fisure 9-Radio Receiver and Transmitter BC-322, with front cover removed. 7 Pars. 4-5 INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 Figure to-Radio Receiver ami Tr.lnsmitter BC-322, left .ide of chassis. gained by releasing the snapslides at the sides and opening the cover. Tubes and the tuning coils may thus be interchanged. The chassis may easily be removed to facilitate inspection or repair by opening the cover and taking out three screws, one at either side of the case and one in the rear . The receiver and transmitter (sometimes referred to as a transceiver), employs the same elements for both receiving and trans mitting. The operation of various elements is changed from receiving to transmitting by alter nate connections effected by the relay which is in turn controlled by the switch on the handset. The set uses a superregenerative detector and radio-frequency oscillator in a modified form of Hartley circuit . Five controls are provided as follows: (1) Channel or frequency adjustment, (2) Calibration switch, (3) Calibration adjustor. (4) Filament rheostat, and (5) Filamenl switch. The meter on the left side of the panel indicate; voltage on the filaments and the socket at the right serves to connect the handset or headset and microphone. Radio Receivers and Transmitters BC-222 and BC-322 are each provided with two dial scale plates, one marked off in 500-kilocycle sub divisions and the other in 400-kilocycle sub divisions. These scales are printed on metal 8 plates which are secured to the front of the panel, one over the other, by means of five machine screws. To interchange the dial scale plates it is necessary to remove the five screws, interchange the plates and then replace the screws. Scales of frequency and dial divisions are given in Section V. The 400-kc scale is provided for experimental purposes in order to determine the feasibility of operating on this channel width with this type of equipment. For ordinary use it is recom mended that the 500-kc scale be employed. 5. Antennas AN29 and AN-30.-Alltennas AN-29 and AN-30 each consist of an assembly of telescoping. aluminum-alloy tubes which may be screwed into place on the insulated antenna mounting on top of the case. See that either antenna is extended to its proper length before attempting to operate. The SCR-194 is operated with all twelve sections of AN-29 drawn out using Coil C-t 74, marked A, with the ten largest or lower sections using Coil C-175, marked B. The SCR-195 is operated with all eight sections of AN-30 drawn out. Note: The calibration of either set will not be correct unless the antennas are extended to the proper lengths at all times or operated complete- Figure Il-Radio Receiver and Transmitter I3C-322, right side of chassis. INSTRUCTION BOOK FOR RADIO SETS SCR-194 AND SCR-195 Pars. 5-7 ly telescoped with only one section in use as described under paragraph 13-Portabl Oper. alion. 6. Mast Sections MS-49, MS-50. and MS- 51.-The mast sections are made of high tensile strength steel. Mast Sections MS50 and 115-51 are fitted with a split shank and screw at one end and a socket sleeve and thread at the other. Mast Section M5-49 terminates in a blunt point at the upper end. Ends which are joined in assembling have enameled marks of the same color. The body of each section is enameled black and bears the type number near the lower end. The overall length of the assembled Mast Sections MS-49, MS-50. and MS-Sl from the top to the bottom of the shoulder of the low end is 9 feet, 4-11/16 inches. The length of Mast Sections M5-50 and MS-Sl similarly measured is 6 feet, 3-7/16 inches. 7. Box BX13.-This article is illustrated in Fig. 13. It consists of a flat rectangular alumi num-alloy box provided with a socket which fits the plug at the bottom of the Radio Receiver and Transmitter BC222 (or BC-322), several binding posts. and a battery cable. It is designed to provide means of connecting separate standard Signal Corps batteries to the set in the event that the Battery BA-32, which was designed especially for use with this set, is not available and to facilitate the insertion of meters in the several circuits. The batteries are connected by means of the cable, all leads of which are identi- Figure 12-Chest CH.33, showing interior. Figure B-Box BX-B. 9 Pars. 7-10 INSTRUCTION BOOK FOR RADIO SETS SCR.194 AND SCR19S tied by stamped metal markers. The binding posts, four on either side, serve to provide ready connection of meters to indicate Microphone Current, Relay Current, Plate Current, and Plate Voltage. Important: If it is desired to use this box without simultaneously connecting meters in circuit, each of the three pairs of binding posts marked MICRO. CUR., RELAY CUR., and PLATE CUR., must be connected with a jumper wire; otherwise there will be three open circuits. 8. Adapter SO-52.-This