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INSTRUCTION PAMPHLET U-5743

INSTALLATION AND MAINTENANCE INSTRUCTIONS

FOR

UNION TRANSISTORIZED UNIT CARRIER

INTRODUCTION

The Union Transistorized Unit Carrier equipment is a keyed frequency type

multi-channel carrier used to transmit CTC codes or to indicate single functions

PRINTED IN U.S.A.

Figure 1 ... Unit Carrier Transmitter and Receiver

A0.64-500-734.1 UNION SWITCH & SIGNAL DIVISION

Westinghouse Air Brake Company

PITTSBURGH, PA. 15218

~

March 1964

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such as block occupancy. The completely transistorized unit provides communication by superimposing carrier on existing physical DC line wires, cable or voice circuits. Utilizing unit carrier equipment, several independent carrier circuits can be added to an existing pair of line wires or cable circuit. The transmitter and receiver units are designed to occupy a rack space equal to that of a standard style PN-150 relay.

SPECIFICATIONS

Frequency Range

The Unit Carrier equipment is available in eighteen channels, one channel every 1000 cycles ranging from 9KC to 21KC and every 2000 cycles to 31KC.

Receiver and Transmitter Impedance

Both the transmitter and receiver are designed to work into a 600-ohm line. When working with an impedance differing greatly from 600 ohms, matching trans­formers must be used.

Transmitter Level

The output level of the transmitter is designed to operate at a maximum of +6 dbm. The transmitter is equipped with an adjustable output control, located on the front of the unit, which permits adjustment of the output level.

Receiver Sensitivity

The receiver is designed to operate at a maximum sensitivity of -15 dbm. Sensitivity of the receiver is adjustable by means of a variable potentiometer located on the front of each unit.

Receiver Output

The receiver will deliver 100 milliwatts of DC power to a 400-ohm load. Additional loads can be connected to the receiver but may result in a slight loss of efficiency.

Voltage Requirements

All power required can be obtained from a standard 10- or 12-volt battery source. When carrier is being transmitted, the transmitter and receiver together draw a total of only 0. 4 watt from the battery (0. 1 watt for the transmitter and 0. 3 watt for the receiver), and when the transmitter "key" is open, during an "off" period of the code, the combined power consumption is only 0. 20 watt (0. 08 watt for the transmitter and 0. 12 watt for the receiver).

Keying Speed

Keying speeds of up to 35 cycles per second can be realized with the proper resistor-relay combination used on the receiver output.

Size and Weight

Each transmitter or receiver unit, including terminals, measures 2-7 /16 inches by 5-1/4 inches by 8 inches and weighs approximately 2-1/2 pounds.

FREQUENCIES AND POWER LEVELS

The direction of transmission of all carrier frequencies should be in accordance

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with the AAR agreement which states that frequencies of 7KC to and including l 7KC shall be transmitted from East to West or North to South and frequencies of l 7KC to 30KC shall be transmitted from West to East or South to North.

The carrier power output levels are in accordance with the AAR specifications for tone equipment of six decibels above the one milliwatt base (+6 dbm).

APPLICATION

The transmitter is a complete assembly and needs no additional material. The receiver is complete except for the receiving relay. The receiver is designed to operate a 400-ohm PN-150 relay which is generally utilized where the carrier circuit indicates one function. When it is necessary to use 120 or 180 code, a 135-ohm CD-F relay or a 360-ohm PC-250B relay with tuned electrical decoding can be used.

Where keying at higher speeds is required, a 1070/1070 KP relay may be used, the coils connected in multiple with a 510-ohm resistor in series. This arrangement allows a keying speed of about 35 cps, although at this rate some pulse distortion may occur.

Unit carrier equipment can be used on and directly connected to open line circuits which are arranged for carrier operation. Most existing lines which are used for voice communications can be used for unit carrier circuits with little or no change to existing facilities. If the line circuit to be used has cable insertions of over 1, 500 feet, matching transformers will probably be required at each end of the cable to pro­perly match the cable to the open line wire or the unit carrier. If the line circuit is made up entirely of cable, matching transformers are required at each end.

If the line circuit to be used is not engineered to handle the proposed unit carrier frequencies, it is recommended that measurements be made to determine the exact loss to carrier that actually exists. The measured attenuation will probably exceed the values derived from standard line wire and cable attenuation data, because the devices on the line may load the carrier and because of absorption losses to other line pairs. From the measured data, it can be determined if the proposed installation will be satisfactory. While the unit carrier is designed to operate over a 21 db cir­cuit, allowances must be made for abnormal line attenuation because of weather con­ditions and equipment aging. The amount of this margin will depend largely on the degree of reliability required. When used on open line a 2:1 or 3:1 margin is often used, thus the normal total attenuation should not exceed 7 to 10 db. When the circuit is entirely in cable, the attenuation does not vary greatly, therefore a normal attenu­ation of perhaps 15 db can be permitted.

As can be seen from the foregoing, it is impossible to predict how many miles the carrier circuit can be operated without actual line data. However, open line con­struction will often permit operation over distances up to 35 miles. Operation in cable will vary from 3 to 10 miles.

CIRCUIT DESCRIPTION

Transmitter

The Transmitter Carrier unit comprises a Hartley-type oscillator and one stage of amplification which also serves as a buffer in preventing line conditions from affecting the oscillator. (See Figure 2. )

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The oscillator circuit is made up of transistor SC!, coil Tl and associated resistors and capacitors. The frequency is controlled by capacitors C2, C7 and the primary coil on Tl. The second winding on Tl provides the feedback required.

cs + -

N

Tl

K

Figure 2 ... Unit Carrier Transmitter Circuit

The signal appears across the third winding of Tl and potentiometer RS, the output control. The signal is fed to the base of transistor SC2 connected as a common emitter class A amplifier. The DC emitter circuit is through R6 to terminal K. When the transmitter is keyed "off", this circuit is open. When keyed "on", terminal K is connected to Kl thus closing the emitter circuit to terminal B.

The signal is fed to output transformer T2 which provides impedance match­ing to a 600-ohm load. Choke T3 and capacitors C4 and C6 make up the output filter which is tuned to the transmitted frequency. This filter blocks DC signals and har­monics of the fundamental frequency from the line circuit and provides a high impe­dance to other frequencies present on the line.

Choke T4 and capacitor CS provide a filter on the battery input to the unit to block voltage surges, which may appear on the battery wires, from entering the unit and damaging the transistors.

Receiver

The Receiver Carrier Unit consists of a tuned input circuit, one stage of Class A amplification, one stage of push-pull power amplification, and a full wave rectifier. All stages are transformer-coupled. (See Figure 3.)

The signal received appears across terminals Ll and L2. Choke T4 and capacitors Cl and C4 make up a tuned input filter which passes the desired frequency

U-S743, p. 4

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and rejects all others. The filter also provides a high impedance to other frequencies on the line circuit.

T3

R6

R3 R4 R5 R7

R8

+ C3

T5

B N -R

Figure 3 . . . Unit Carrier Receiver Circuit

Voltage of the desired frequency appears across the primary of Tl. The signal then appears across potentiometer Rl, the sensitivity control. The desired amount of signal is fed to the base of SCI which operates as a common emitter Class A amplifier.

Capacitor CS and transformer T2 comprise another tuned circuit to improve the receiver selectivity. Any signal of a foreign frequency which may have passed through the input filter will be rejected here.

The output of T2 is fed to the base of transistors SC2 and SC3 which are operated Class B push-pull. The secondary of T3 is connected to a full-wave rectifier to produce a DC receiver output suitable for energizing a relay.

MAINTENANCE

Test Instruments

The test instruments listed below are recommended for shop and field main­tenance of the Union Transistorized Unit Carrier equipment. These instruments will, in many cases, do more than is required for this application, but can be readily used in maintenance of most types of electronic equipment.

1. A Volt-Ohm-Milliammeter having a DC sensitivity of 20, 000 ohms­per-volt, such as the Simpson Model 260 Analyzer, is satisfactory for measuring all

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DC voltage since extremely high internal impedances are not present in the unit carrier equipment.

2. A Transistor Tester, such as the Simpson Model 650 Add-A-Testor, capable of measuring moderate values of Beta as well as Ico is desirable.

3. A variable frequency oscillator, such as Hewlett-Packard Model 200CD Oscillator, which covers the 9KC to 31KC frequency range is required.

4. A vacuum tube voltmeter, such as Hewlett-Packard Model 400D or 403A Vacuum-Tube-Voltmeter, is necessary for measuring AC voltage.

5. In maintenance of any electronic equipment, visual observation of existing waveforms for evidence of overloading, clipping, and so forth, often proves to be extremely valuable in shooting trouble. Therefore, a good oscilloscope such as Hewlett-Packard Model 120-A Oscilloscope, should be available.

6. An electronic counter, such as Hewlett-Packard Model 521-C Counter, provides a most satisfactory method of checking carrier frequencies. It provides ac­curate data display which requires a minimum of time for interpretation.

Transmitter Test Set-Up

1. Connect the transmitter to the test equipment as shown on the Transmitter Data Sheet, Figure 4.

2. Adjust B-N voltage to 10 volts. The DC current drawn should not exceed 15 ma.

3. Rotate the transmitter output control, RS, to the maximum clockwise position.

4. Check the frequency being transmitted. It should be within 20 cycles of that called for on the nameplate.

5. Check the output voltage. It should be a minimum of 1. 5 volts.

6. If the unit is off frequency, it may be retuned by adjusting trimmer ca­pacitor C7. When retuning, it is recommended that the frequency be adjusted to within 5 cycles of the nameplate frequency.

7. If the transmitter oscillator is retuned or the output voltage is slightly low, the output filter should be retuned.

8. Adjust trimmer C6 for maximum output.

9. The output waveform should appear as a sine wave on the oscilloscope.

10. If output signal is not present or an inadequate output is obtained, isolate trouble by performing point to point voltage checks as indicated on the Transmitter Data Sheet, Figure 4.

11. A sine wave should be observed on the oscilloscope at the input to the amr: lifier. The output wave shape should appear as a sine wave, except for a small amoun of clipping.

U-5743, p. 6

Receiver Test Set-Up

1. Connect the receiver to the test equipment as shown in Figure 6.

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2. Adjust B-N voltage to 10 volts. The DC current drawn should not exceed 15 ma maximum with no input signal on Ll-L2.

3. Rotate the receiver sensitivity control, RI, to the maximum clockwise position.

4. Reduce the oscillator gain if an output greater than 6 volts appears across the 400-ohm load resistor.

5. Vary the frequency of the oscillator above and below the nameplate fre­quency. Note that the voltage across the 400-ohm load resistor peaks. Adjust the oscillator frequency to where the output voltage peaks. This frequency should be within 30 cycles of the nameplate frequency.

6. Adjust the signal level to produce 5. 7 volts across the 400-ohm load re­sistor. The input signal should not exceed -15 dbm.

7. Increase the signal voltage. The output voltage should saturate at about 7 to 7-1/2 volts and go no higher, even with increased input.

8. If the receiver is inoperative, perform the point to point voltage checks as indicated on the Receiver Data Sheet, Figure 6.

9. Connect the oscilloscope from collector to collector (PCB Reference Points 3 and 11) of the push-pull amplifier. With up to 5. 7 volts measured across the 400-ohm load resistor, a sine wave should appear on the oscilloscope. At 7. 5 volts output, a square wave will appear on the scope as the amplifier reaches saturation.

10. Through the input filter circuit, the Class A amplifier circuit and coupling transformer, a sine wave should be observed on the scope.

11. If the receiver is not on frequency, it may be retuned as follows:

a. Temporarily remove the test leads from terminals LI and L2 (see Receiver Data Sheet) and reconnect to the outside terminals of potentiometer RI.

b. Adjust the output of the oscillator until meter VI reads from 0. 002 to 0. 005 volt.

c. Vary the oscillator frequency and note the frequency at which the output voltage peaks. This measured frequency should be within 30 cycles of the nameplate frequency.

CAUTION

If the voltage across the load resistor exceeds 6 volts, the input voltage must be adjusted to a lower value.

d. If the measured frequency is not within 30 cycles of the nameplate frequency, the value of capacitor C5 must be changed. If the unit peaks at a frequency higher than that indicated on the nameplate, additional capacitance is required. (Use only high quality silver-mica capacitors.) After changing capacitors, the frequency response should be within 15 cycles of the nameplate frequency.

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e. Remove the test leads from the outside terminals of potentiometer Rl and reconnect to terminals Ll and L2.

f. Adjust the output level of the oscillator until a reading of 2 to 3 volts is measured across the 400-ohm resistor.

g. Set the frequency to that called for on the nameplate.

h. Rotate the adjusting screw of trimmer capacitor C4 for maximum voltage across the load resistor.

CAUTION

If the voltage across the load resistor exceeds 6 volts, the input voltage must be adjusted to a lower value.

i. Vary the oscillator frequency and note the frequency at which the out­put voltage peaks. The frequency should be within 15 cycles of the nameplate frequency.

j. After tuning the receiver, repeat sensitivity check as called for in step 6 above.

U-5743, p. 8

DATA SHEETS

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SCOPE VTVM

HEWLETT PACKARO 400C OR EQUIVALENT

ELECTRONIC FREQUENCY MEASURING SYSTEM

100 ...

ELECTROLYTIC 100 TO 150 OHM POT 2 WATTS OR HIGHER CAPACITOR IOOMFD. !IOV.

12-14V D.C.

+

SCHEMATIC

DIAGRAM

PCB REF. POINTS

cs • R

AC

(HIGHER CAPACITY AND

VOLTAGE MAY BE USED.)

0-IOV

+

G

N

PCB. REF. POINTS Meter Pos.

VOLTAGE Neg. Pos.

Ground Lead Lead Lead

Ll L2 1. 5 (or over) l 4 l 2 6.6 1 3 1 7 0.18 l 2 l 10 10.0 1 7

14 15 15 16 16 17

B-N Input: 10 Volts Output Control: Max. CW 10% Tolerance

2.8 7.5 8.0

1 9 1 10 1 13

Battery } Key Closed - 10 ma Current Key Open - 8 ma

JUMPER K I. Kt

II

G

K

DC

K

L1

8

VOLTAGE

8.9 8.85 0.0 9.6 9.6 9.6 9.8

K1

L2

N

VOLTAGE

TABLE

TEST

Figure 4 ... Unit Carrier Transmitter Data Sheet

U-5743, p. IO

CIRCUIT

C7 C6 T2 R9 R8 RIO Tl R2

CAPACITORS RESISTORS

TOL. U.S.& S. RES. TOL. U.S.& S. REF. MFO. % VOLTS PC. NO. USED ON REF. OHMS % WATTS PC. NO. USED ON

CI .27 100 UJ706092 All R2 lK ±5 0.5 UJ720882 All C2 .01 t2 500 Uj700619 9KC (two) R3 1500 ±5 0.5 Uj721064 All

.01 ±2 500 UJ7006!9 } !OKC .007 t2 500 Uj70!003

R4 !OK ±5 o. 5 UJ720883 All R6 56 ±5 0.5 UJ721190 All

.01 ±2 500 Uj700619 } l!KC .0025 ±2 500 UJ7006!5

R7 56 t5 o. 5 U 721190 All RB 56 ±5 0. 5 Uj721190 All

.01 t2 500 Uj700619 !2KC R9 1500 ±5 u.5 UJ72lu64 Ah

.009 ±5 300 UJ700543 lJKC

.01 ,2 500 Uj7006!9 }14KC .001 ±2 500 UJ700612

.009 ±5 300 Uj700543 l5KC

.008 ±2 300 Uj70966 l6KC POTENTIOMETER

.007 ±2 500 Uj70!003 l7KC

.0062 ±5 500 Uj702957 18 & 19 KC

.01 ±2 500 Uj700619 20KC

RES. TOL. U.S.& S. REF. OHMS % WATTS PC. NO. USED ON

.009 !5 300 Uj700543 21, 23 & 25KC Rl 50 ±IO 2.0 UJ62297 All

.008 ±2 300 Uj70966 27KC

.007 ±2 500 Uj70l003 29KC

.0062 ±5 500 Ul702957 JIKC CJ .22 ±20 100 UJ702304 All THERMISTOR

C4 .008 ,2 300 UJ70966 9KC RES. TOL. U.S.& S. .0062 ,5 500 Uj702957 IOKC REF. OHMS @25'C PC. NO. USED ON .003 ,2 500 Uj700616 llKC .002 ,2 500 UJ700614 12KC RIO 10 ±10% UJ730838 All

.0015 ±2 500 UJ700613 13 & 14KC

.001 ±2 500 Uj700612 15 & 16KC

.002 ,2 500 UJ700614 17KC

.001 ,2 500 UJ700612 18, 19, 20, 21 & 23KC TOROID INDUCTORS

.0005 ,2 500 Uj700712 25, 27 & 29KC INDUCTANCE MH ±13\lb U.S.& S.

.0004 ,2 500 Uj700937 31KC REF. 1st winding PC. NO. USED ON c, 100 +100 25 Uj70826 All

• 10 Tl 15. l UN385101 9KC thru 13KC

Cb 180-690* 500 Ul706064 All 10.9 UN385102 14KC thru 19KC

C7 180-690" 500 UJ706064 All CB .001 ±5 500 Uj702998 All

UN385103 20, 21 & 23KC 3.8 UN388064 25, 27, 29 & 3 lKC

T3 63. l UN385104 9KC thru 16KC

• Micromicrofarad 36.3 UN385105 17KC thru 31KC

TRANSFORMER

U.S.& S. REF. TURNS PC. NO. USED ON

TRANSISTORS T2 PR!. to

SEC. UN379508 All 250 67

U.S.& S. REF. TYPE PC. NO. USED ON COIL

SCI 2N44 Uj730754 All SC2

RES. TOL. U.S. & S. REF. TURNS OHMS \lb PC. NO. USED ON

T4 150 0.40 ±IO UN345129 All

PARTS LIST

Figure 5 . . . Unit Carrier Transmitter Components

U-5743, p. 11

LI

L2

PCB REF. Meter

Ground

Ll

1 10 10 10 10 10 10 10 10 9

600 OHM TO 3-15 OHM MATCHING TRANSFORMER.

SEE TEXT ,.--..

Rx MUST BE NON- INDUCTIVE ANO COVER THE RANGE OF 200 TO 700 OHMS.

12-14V o.c.

C4

100 TO ISO OHM POT + 2 WATTS OR HIGHER

SCHEMATIC

DIAGRAM

POINTS AC

PCB. REF. Pos.

VOLTAGE Neg.

Lead Lead

L2 0. 03-0. 13 10 (varies with 10

input) 10 6 0.003 10

21 0.013 10 4 l. 5 10 8 2.9 10

13 0.24 15 0.004 12 0.24 3 5.8

11 5.8 5 7.5

ELECTROLYTIC CAPACITOR IOOMFO. SOV.

(HIGHER CAPACITY ANO

VOLTAGE MAY BE USED.)

o-1ov.

+

4

21

R2 R4

10

20 + C3

TS

BK

B N

POINTS DC

Pos. VOLTAGE

Lead

1 9.3 21 9.5

4 0.0 15 9.9 14 9.8 3 0.0

11 0.0

B-N Input: 10 Volts Battery } Zero Input Signal - 13 ma Current 5. 7 V across load - 22 ma Sensitivity Control - Max. CW

10% Tolerance

LI L2

B N

R6

RS R7 20

R8

VOLTAGE

TABLE

Figure 6 . . . Unit Carrier Receiver Data Sheet

U-5743, p. 12

TEST

CIRCUIT

T3

3 II

l!IOT BK

13ST

II

10

8

G

-R

i

Ii'

CAPACITOM

TOI., u.u.,a. l\l!I', Ml'D, VOi.Ti PC, NO, UIIID ON

Cl 150* A3,3 UJ700781 9KC lhru 13KC 120' u UJ706263 16, 17 I IIKC 68* n UJ700800 19, 20 • 21KC ai• H UJ702781 23, H l a?KC 3• • 7 278 a 3

S•• ,018 *2 300 UJ700620 IOKC Nott ,009 *5 300 UJ700S43 "Au ,015 t2 300 UJ700620 llKC ,005 ia aoo UJ700618

,015 d 300 UJ700620 12KC ,001 u 500 UJ700612 ,01 u 500 UJ700619 13KC ,008 i2 500 UJ700618 ,01 u 800 UJ700619 14KC ,0025 i2 500 UJ700618 ,01 i2 500 UJ700619 lSKC ,009 •5 300 UJ700543 16KC .ooa i2 300 UJ70966 17KC ,007 •2 800 UJ701003 18KC ,008 •2 800 UJ700618 19KC ,0018 d 800 UJ700613 ,004 •2 500 UJ700617 20KC ,0018 •2 aoo UJ700613 ,008 •2 800 UJ7006!8 21KC ,01 t2 aoo UJ700619 23KC ,008 •2 300 UJ70966 28KC .007 d 800 UJ701003 27KC ,0062 •5 800 UJ702957 29KC ,008 .a aoo UJ700618 31KC

H ,001 •2 800 UJ700612 ,0008 u 500 UJ700712 ,0004 •2 500 UJ700937 All (H required) ,0003 •2 500 UJ700608 ,0002 .a 500 UJ700603 ,0001 tS 500 UJ700687

C6 ,27 500 UJ706092

NOTS "A": Unite tuned by meana of capacitors C5 ptua trimmers aa required.

• Micromtcrofarad

DIODES

u.s.&s. REF, TYPE PC, NO, USED ON

DI D2 Tl2G UJ723303 All D3 D4

PARTS LIST

POTl!NTIOMl!Tl!l\

RIIS, TOI., u.a.11. l\111', OHMS " WAffl PC, NO, UBIID ON

l\l SOK uo 0,23 U 620398 All

THlll\MlllTOl\

RIIS, TOI., u.1.,1. Riii', OHMS caa•c PC, NO, USl!D ON

l\5 25 i!0\16 U 723008 All

TOl\OID INDUCTORS

INDUCTANCB MH "13\16 u.s., s. RBP, 111 wlndlng PC, NO, USBD ON

T2 9, 7 4, 7 4 2 350 270 200 148

TRANSPOI\Mi!RS

u.s.u. REP, TURNS PC, NO. USED ON

Tl PRI, IO s~~· UN379643 All

" T3 PRI, IO

SBC, UN379644 All 300 135

COii.

RBS, TOL, U, S, & S, REP, TURNS OHMS \16 PC, NO. USED ON

TS 150 0,40 UO UN348129 All

TRANSISTORS

u.s.u. REP, TYPE PC, NO, USED ON

SCI SC2 2N44 UJ730754 All SC3

Figure 7 . . . Unit Carrier Receiver Components

U-5743, p. 13