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MK. 123 TRANSMIT tER/RECEIVER

MANUAL

Part I contains Operating Instructions

Part II contains Technical Information

Either Part may be removed at thediscretion of the Issuing Officer

T E C H N I C A L P U B L I C AT I O N N O . S Z

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Mk. 123 TRANSMITTER/RECEIVER

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Mk. 123

PART 1

O P E R A T I N G I N S T R U C T I O N S

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PA R T: 1

C O N T E N T S

Section

1

22.12.22.3

33.13.23.3

55.15.25.35.45.55.65.75.85.95.10

66.16.26.36.46.56.66.7

ACCESSORIES AND SPARES

PHYSICAL DATAS e t o n l y . . . . . . . .Spares and Accessor ies . .Complete Packed Equipment . .

GENERAL DESCRIPTIONB r i e f D e s c r i p t i o n - . . . .Receiver Frequency CoverageTransmitter Frequency Coverage

FUNCTION OF CONTROLS

OPERATING INSTRUCTIONS . .Before connecting to the mainsThe use of the Condenser Re-formerTo Re-form CondensersSetting the Voltage SelectorConnecting up the EquipmentTo Receive a Station . .Use of the B.F.O.To Log a Station. . . .Hand Generator Operation12 volt Accumulator Operation

TUNING THE TRANSMITTER .Selection of Crystals , .To Transmit on a FundamentalTo Transmit on the Second HarmonicTo Log the Transmitter SettingsCheck Keying of Oscillator . .Operational NotesExamples of Transmitter Settings

Page

4

555.5

6677

1111111212141414151717

1919192021212122

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C O N T E N T S(Continued)

S e c t i o n P a g e

7 A E R I A L S . . 2 37 . 1 G e n e r a l . . 2 37 . 2 T r a n s m i s s i o n f r o m a n A e r i a l W i r e . • 2 37 . 3 D i r e c t i o n o f T r a n s m i s s i o n . . ♦ . 2 47 . 4 A e r i a l P l a n n i n g . . . . . . . • 2 97 . 5 U s e o f I n s u l a t o r s 3 07 . 6 O t h e r A c c e s s o r i e s . . . . • • 3 07 . 7 A e r i a l L a y o u t s 3 17 . 8 • T h e E a r t h . . 3 4

8 F A U L T S A N D R E M E D I E S . . . . 3 68 . 1 G e n e r a l . . . . 3 68 . 2 R e c e i v e r 3 68 . 3 T r a n s m i t t e r 3 88 . 4 O v e r h e a t i n g o f t h e E q u i p m e n t . . 3 9

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ACCESSORIES AND SPARESSee Fig. 1-1

Descript ion Stock No.

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100

Receiver/Transmit ter/Power Pack

Mains Lead Assembly (complete withUniversal Mains Adaptor)

Crystal Adaptor AssemblyPlug 2-pin (for external key)Phones completeCondenser Re-formerTransit CaseValve 5A/163KValve CV428Valve CV465Valve CV466Cartridge Fuses, 4 Amp. (miniature)Egg Insulators (small)Pliers (small)Screwdriver (small)Neon Testerft Wire 14/36 swg TC PVC covered blackPlate (on which aerial wire is wound)Earth Rod and RingB8D Pin Aligning ToolTerminals (black)Shorting LinkReel AerialAllen Key 6BACanvas Carrying CaseFuses, 15 Amp

123

123-20

123-470P201H124J123-600939D0385A/163KCV428CV*65CV466FC4MA100W5440 .W5703A1300/-K1.074383A034A254BVB18AP101B123H-701600/-W5403969C015FC15

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2 P H Y S I C A L D A T A

Set only

WeightLengthHeightWidth

7 lb 12 oz.11 3/8 in.3 3/8 in.5 3/8 in.

3.5 kg29.9 cm8.5 cm

13.6 cm

Spares and Accessories

12feet (4.2m) of twin core mains cable, plug adaptors,phones and crystal adaptors etc. as listed insection 1.

2.3 Complete Packed Equipment

The equipment is supplied in two TransitCases - the Mk. 123 Transmitter/Receiver in onecase and the Mk. 123 Spares Kit and canvas carryingcase in the other. The two transit cases are providedwith a poly ether foam lining.

Mk. 123 TX/RX in Transit Case

Weight 19 lb 4 oz. 8.6 kgLength 19| in. 49.5 cmHeight \2\ in. 31.75 cmWidth 11 1/4 in. 28.75 cm

Spares Kit and canvas case in Transit Case

Weight 8 lb 12 oz. 3.97 kgLength \b\ in. 39.37 cmHeight 12! in. 31.75 cmWidth 7 in. 17.78 cm

T P 8 2 6

3 G E N E R A L D E S C R I P T I O N

3 . 1 B r i e f D e s c r i p t i o n

The Mk. 123 is a compact, portable Transmitter/Receiver operating in the waveband 2.5 Mc/s to 20 Mc/s(150 to 15 metres).

The receiver is a superheterodyne with a singleradio frequency (RF) stage and is suitable for thereception of continuous wave (cw), modulated continuousv/ave (mew) and telephony (rt) signals. On mew it hasa sensitivity of better than 10 microvolts for 10 dBsignal to noise ratio and on cw signals the beat frequencyoscillator (BFO) provides a gain of 15 dB at 1 Kc.

The transmitter is for cw only and can be handkeyed with the built-in morse key. An external hand keyor mechanical keyer may also be used via the externalkey jack plug. Limitations to this use are:

(i) maximum keying speed of 40 wpm (due to*Q* of the crystal)

(ii) keyer must accept the bias voltage of 135V.The transmitter may be matched into any aerial likelyto be used, and will deliver a power output ranging.from15 to 25 watts.

The power supply unit is in the same case,situated between the transmitter and the receiver. It isdesigned to operate from a supply of A.C. ONLY, 40-250 c/s.It has tappings every 10 volts between 100 and 150V andbetween 200 and 250V.

A re-former unit is available which enables theelectrolytic capacitors to be re-formed after a periodof storage.

In addition, an external power supply unit - theMk. 123V - is available to operate the equipment froma 12 volt accumulator. A hand generator - the Mk, 810A -may also be used to power the Mk. 123 direct, or to chargea 12 volt accumulator via the Mk. 812A charging unit.

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3 . 1 T h e e q u i p m e n t i s s u i t a b l e f o r u s e i n a m b i e n tCont. temperatures from 0°C to 45°C - and thus will operate

satisfactorily under tropical conditions. Its useout of doors under tropical conditions or continuouslyunder very high humidity conditions is not, however,recommended.

3.2 Receiver Frequency Coverage

B a n d F r e q u e n c y c o v e r a g e

Band 1Band 2Band 3

2.5 - 5 Mc/s5 - 10 Mc/s

1 0 - 2 0 M c / s

3 .3 Transmi t te r Frequency Coverage

B a n d F r e q u e n c y c o v e r a g e

Band 1Band 2Band 3

2.5 - 5 Mc/s5 - 1 0 M c / s10 -20 Mc /s

Power Output

19 - 25 watts15-25 watts13-25 watts

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Controls - Fig. 4-1

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FUNCTION OF CONTROLS

All controls on the Mk. 123 are numbered and theirfunctions are as follows:-

N o . S y m b o l F u n c t i o n

1 W a v e - C h a n g e S w i t c h R e c e i v e r

2 0 j — P h o n e< » B e a t - F r e q u e n c y O s c i l l a t o r ( B F O ) S w i t c hT ^ » M o r s e

3 B F O T u n e

4 ~ 1 / \ G a i n C o n t r o l^r5 R e c e i v e r D i a l

6 T u n i n g K n o b

d7 J P h o n e S o c k e t

8 — L - E a r t h S o c k e t

9 Y A e r i a l S o c k e t

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4 F U N C T I O N O F C O N T R O L S ( C o n t i n u e d )Cont.

N o . S y m b o l F u n c t i o n

1 1 T r a n s m i t t e r / R e c e i v e r C h a n g e - o v e r S w i t c h

1 2 " W a v e - c h a n g e S w i t c h - T r a n s m i t t e r

1 3 D r i v e T u n i n g I n d i c a t o r N e o n

1 4 A e r i a l T u n i n g M e t e r

f1 5 r / - > D r i v e T u n i n g K n o b

1 6 | E x t e r n a l M o r s e K e y S o c k e t

1 7 / P o w e r A m p l i fi e r ( P A ) T u n i n g K n o b

1 9 I C r y s t a l S o c k e t

T2 0 M o r s e K e y ( i n t e r n a l )

2 1 ^ \ y M a i n s V o l t a g e S e l e c t o r

These numbers are referred to within bracketsthroughout the Manual e.g. Gain Control (No. 4).

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5 O P E R A T I N G I N S T R U C T I O N S

5.1 Before connecting to the mains

Ascertain the mains voltage and nature of supply- that is, alternating current (a.c.) or direct current (d.c.) -preferably by inspection of the Supply Meter or measurementwith a reliable meter. A rough guide to the voltage andnature of supply can be made with the neon tester. Plugthe two leads into the mains and compare the way the neonslight up with the picture on the case.

Use the Electrolytic Condenser Re-former if theequipment has been in store.

5.2 The use of the Electrolytic Condenser Re-former

If the equipment has been in store for a year or more(six months in a warm climate), the condensers willrequire re-forming - that is, the electrolytic dielectricinsulation will have become insufficient and must be builtup again. This can be done by applying a reducedvoltage to the condensers. The leakage current willinitially be quite high (because the insulation is inadequate)but will gradually fall (as the dielectric insulation becomessatisfactory). After an hour or two the condenser will beable to withstand the full voltage with negligible leakagecurrent.

If this re-forming process were not carried out andthe full voltage were applied to the condensers after aprolonged period of disuse, damage would occur to thecondensers, and possibly to the rectifiers, by overheatingduo to the extra current being pasted.

The Electrolytic Condenser Re-former is made in theform of a unit for insertion between the 18-pin mains plugand the equipment itself.

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5 .3 To Re- fo rm Condensers

1. Set the mains selector to the same voltage as the# a.c. supply (see section 5.4).2. Insert the Condenser Re-former between the 18-pin

plug and socket (No. 10) - see Fig. 5-1.3. Switch (No. 11) to receive - to the left.4. Insert the mains plug into the supply socket - a.c. ONLY.5. Leave the set for two hours, then switch (No. 11)

to transmit - to the right - and leave the set for afurther period of two hours. The morse key shouldnot be pressed during the re-forming process:

6. After this period the condensers should be satisfactory.7. A rough check on the condition of the condensers can

be made by observing the temperature of there-forming unit after this period of processing:-

R e - f o r m i n g u n i t C o n d e n s e r s

c o l d g o o d c o n d i t i o n - d i d n o trequire re-forming.

w a r m g o o d c o n d i t i o n - r e - f o r m i n gsat isfactory.

hot or very hot at least one condenser faulty -replace prior to use.

5.4 Setting the Voltage Selector

The voltage selector (No. 21) consists of two rotatableknurled edges. Rotate these edges until the correctvoltage can be- seen in the window. Care should be takenwhen handling equipment that the voltage setting is notaccidentally altered.

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5.5 Connecting up the Equipment

1. Select the mains plug pins to suit the power socket.2. If the equipment has been unused or in store for

twelve months (six months in a warm climate) ormore, re-form the condensers as described insection 5.3.

3. Set the change-over switch (No. 11) to receive - tothe left,

4. Connect the mains lead to the plug (No. 10).5. Connect the aerial lead to socket (No. 9).6. Connect the earth lead to socket (No. 8). /a^7 . C o n n e c t t h e p h o n e s t o s o c k e t ( N o . 7 ) . 18. Connect to mains supply.

Note: For details of use with the Mk. 123V unitplease refer to Technical PublicationNo. 95 Section 3,

5.6 To Receive a Station

1. Switch (No, 11) towards the receiver and allow theequipment to warm up for a few minutes.

2. Switch (No. 1) to the required waveband.Band 1 2 .5 -5 Mc /sBand 2 5 - 10 Mc/sBand 3 10 - 20 Mc/s

3. Switch (No. 2) - the Beat Frequency Oscillator switch -to ON to receive morse signals or to OFF forspeech or broadcast stations.

4. Set the BFO control (No. 3) to the central position.5. Set the Gain control (No. 4) for a suitable level.6. Search for the station to be received, on or near its

frequency as shown on the dial (No. 5), using thetuning knob (No. 6). Calibration accuracy is 1%towards the centre of theiscale and 0.2% at thealignment points at each end of the scale. To loga station refer to section 5.8.

5-7 Use of the B.F.O.

The B.F.O. has three main uses:-

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5.7.1 To alter the tone of the morse signalThe BFO control is brought into operation

by the BFO switch (No. 2). By rotating thet knob (No."3), the pitch or tone of a morse signal

may be varied by as*much as +10 Kc/s.

5.7.2 To find the carrier frequency of a station

Set the BFO tuning knob to its centralposition and tune the station with the main tuningcontrol (No. 6) for zero beat or until a lowpitched whistle is heard. This is the correctsetting .for that station and a log reading may betaken for future reference. If a broadcast stationis being logged, do not forget to switch the BFOoff after use.

5.7.3 To separate two interfering morse stations

The BFO may be used to separate two adjacentstations whose signals are so close together thatneither can be read. Tune the unwanted signal tozero beat, or a very low pitched whistle. Thewanted signal will rise in tone and be readable.Alternatively, the unwanted station may be tuned bythe BFO to a very high pitch and so make the wantedsignal more readable.

5.8 To Log a Station

When a particular station has been found and theOperator would like to return to that station, he may do soby using the Log Scale which is effectively 80 inches long.

This scale has twenty divisions on the dial (No. 5) andeach division is further divided by the scale on the knob(No. 6) which has ten m-iin divisions, each divided intofive parts. Each part may be read to half a division which

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5.8 is 0.01 of the dial reading. It must be rememberedCont. that these Log numbers are to enable the Operator to

re-set the dial to a Station and must not be taken torepresent the frequency or wavelength of that Station.

To take the Log number of a Station, make a note ofa number lying under the cursor line on the dial (No. 5),to this number must be added the reading of the tuningknob (No. 6). The diagrams below show the receiverdials as they would appear on the set when taking aLog reading. /^^

Log: 8.26 Log: 5.98 Log: 6.04

Care must be exercised whilst taking a Log readingwhen the cursor line is almost between two numbers onthe dial (No. 5). The second example is sometimesincorrectly read as 6.98 but if you examine the twodecimal, figures .98 you will see that with a little moreclockwise rotation of the knob (No. 6) the next figures willbe 6.00 - 6.02 - 6.04 etc. So clearly the figure in frontof .98 should be 5, making the correct Log reading 5.98.

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5.9 Hand Generator Operat ion

The Mk. 123 may also be powered by the Mk. 810Ahand generator. The mains voltage selector of theMk. 123 should be set to 110 volts for operation onthe hand generator.

The generator must be fixed in position by itsclamps and then turned at approximately 65 r.p.m.keeping the meter reading between the two markson the dial.

The output of the generator is approximately110 volts 40 to 80 watts at 225 c/s*

Further details are available in TechnicalPublication No. 90.

5.10 12 volt Accumulator Operation

The Mk. 123 may also be powered by a 12 voltaccumulator through the Mk. 123V inverter unit..Details are available in Technical Publication No. 95.The connections are illustrated in Fig. 5-2.

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6 T U N I N G T H E T R A N S M I T T E R

6.1 Selection of CrystalsWhere transmission is required on frequencies

between 2.5/5 Mc/s the crystal will have a frequencyequal to the transmission frequency. Where transmissionis required between 5/10 Mc/s the crystal will have afrequency equal to the transmission frequency or one-halfof the transmission frequency. Where transmission isrequired on frequencies between 10/20 Mc/s the crystalwill have a frequency equal to one-half of the transmissionfrequency.

Crystals Style *A\ 'C* or Type FT, suitable for usein an oscillator circuit where crystal currents up to 60milliamperes may be expected, may be used with the Mk. 123.

Equivalent parallel capacity of the oscillator: -30 pf.Stability and temperature range of the crystals should

be specified to suit the User's requirements.

6.2 To Transmit on a Fundamental, (crystal frequency)

1. For the purpose rf this example, it is assumed thata crystal of 2*690 Mc/s is to be used.

2. Connect the aerial, earth and power cables as insection 5.5.

3. Set the Transmit/Receive switch (No. 11) to theright - i.e. towards the transmitter.

4. Plug the crystal into the socket (No. 19).5. Set the Bandswitch (No. 12) to the waveband on which

transmission is required, i.e. 2.5-5 Mc/s.6. Press Key (No. 20).7. Adjust the Crystal Tuning Knob (No. 15) for maximum

illumination of the Neon (No. 13). If two tuningpoints are observed, take the lower dial readingas the fundamental.

8. Release Key (No. 20).Note: After the key has been released andpressed again, it is occasionally found that thecrystal does not re-commence oscillation - in whichcase a slight readjustment of the crystal tuning knobis required.

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6.2 9, Set the Aerial Input Matching Switch (No. 18)C o n t . t o p o s i t i o n 1 .

10. Press the Key(No. 20).11. Adjust the Aerial Tuning knob (No. 17) to obtain

a maximum reading (No. 14). Compare thisreading with those obtained with the switch(No. 18) in positions 2, 3 and 4. Release thekey while the switch is being moved. Retune(No. 17) for maximum meter reading each time.Whichever switch position gives the highestpossible meter reading is the best position -t h i s r e p r e s e n t s t h e m a x i m u m t r a n s f e r o f p o w e r - ;to the aerial at this frequency.

6.3 To Transmit on the Second Harmonic

1. The transmitter will *double* on any crystal lyingin the frequency range 2.5 to 10 Mc/s. Forexample, if a 7*120 Mc/s crystal is to be used,a signal can be sent out on 14*240 Mc/s - whichis the second harmonic or double the crystalfrequency,

2. The transmitter is set up as before but in this casethe Bandswitch (No. 12) is set to the bandcovering the doubled frequency e.g. twice thecrystal frequency of 7*120 Mc/s is 14*240 Mc/s -therefore use Band 10-20 Mc/s.

3. Press the Key (No. 20).4. Adjust the Crystal Tuning knob (No. 15) for maximum

illumination of the Neon (No. 13) - if two tuningpoints are observed, take the one occurring at thehigher dial reading as the second harmonic.

5. Release the Key (No. 20) and continue as above - insections 12.2.9 to 12.2.11.

6. It may happen, at certain frequencies, that two tuningpoints are observed whilst adjusting either theAerial Tuning knob (No. 17) or the CrystalTuning knob (No. 15). This occurs when both thefundamental and second harmonic frequencies appearwithin one waveband, e.g. a 5 Mc/s crystal will tuneon 5 and 10 Mc/s on the 5-10 Mc/s waveband.

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6.3 7. It is possible to tune the P.A. (No. 17) to aCont. harmonic of the dr ive f requency. This is

undesirable as, in general, less power outputis obtained.* To obviate this, ensure that theP.A. tuning condenser (No. 17) and drivecondenser {Mo. 15) are set to approximately thesame relative positions when tuned. Thebandswitch should be set to the range in whichthe required output frequency lies.

6.4 To Log the Transmitter Settings

The setting of the control knobs for any given aerialand crystal may be logged to reduce the time required fortransmitter tuning on subsequent occasions, i.e. note thecrystal frequency, waveband and settings of controls Nos.15, 17 and 18.

6.5 Check Keying of Oscillator

If, after tuning as above, the transmitter will not*key* (that is, the Neon (No. 13) will not re-strike),detune the drive tuning control (No. 15) a little and thencomplete the tuning procedure.

6.6 Operational Notes when Tuning to the Second Harmonic

Care must be exercised when making a transmissionon the second harmonic. Make sure that the bandswitchis set to the band that covers the second harmonic ofthe crystal in use.

Tune to that part of the band that you would expectthe second harmonic to appear in, e.g. if a 6 Mc/s crystalis in use and a transmission is required at 12 Mc/s,tune to appropriate part of the 10-20 Mc/s band. That is,in this example, the lower end of the band - in order toavoid the third harmonic of 18 Mc/s at the higher end ofthe band.

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6.6 Control knobs (Nos 15 and 17)Cont. are marked 1 to 10 as shown. The

low frequency end is anti-clockwisewhile the high frequency end isclockwise. The figures 1 to .10 onthe two knobs are arbitrary figuresand must not be taken to representspecific frequencies.

, i > H - F - E N D

The position of control No. 17 may be influenced bythe aerial matching switch (No. 18). If, after tuning up,the aerial matching switch (No. 18) is altered, re-checlfthe setting of the aerial tuning knob (No, 17).

6.7 Examples of Transmitter Settings

TX on Xtal in Drive P.A. Band OutputFreq use - Tuning Tuning Switch PowerMc/s Mc/s Watts

2.5 2.5 0- 5 0- 5 2.5- 55.05.0

2.52.5

5-100- 5

5-100- 5

2.5- 55.0-10 15

5.0 5.0 5-10 5-10 2.5- 55.0 5.0 0- 5 0- 5 5.0-10 to

10.0 5.0 5-10 5-10 5.0-10 "% e

7.5 7.5 3- 7 3- 7 5.0-10 2515.010.0

7.510.0

3- 75-10

3- 75-10

10.0-205.0-10 watts

10.0 10.0 0- 5 0- 5 10.0-20i _ £ M _ 10.0 5-10 5-10- 10.0-20

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7 A E R I A L S

7 . 1 G e n e r a l

The efficiency of aerials, particularly withinbuildings, depends on many factors not easily measuredor described. The following paragraphs include asimple description of the radiation of energy from aerialstogether with suggestions on how to erect aerials in afew selected circumstances. It is emphasised that thegreatest efficiency is still obtained from an aerial of >adequate length installed out of doors away frombuildings or other tall objects. In particular, steel-framed buildings effectively screen the radiation froman aerial.

7.2 Transmission from an Aerial Wire

When current from the radio transmitter flows inthe aerial wire, transmission occurs. The greatesttransmission occurs where maximum current flows.The amount of current flowing varies along the lengthof the wire and is usually small in a short aerial. Thegreatest current flows some distance from the end of thewire. For convenience this distance will be called *D*.

Figure 7-1 gives some idea of how transmissionvaries along the aerial wire when the wire is longerthan distance *D'. The distance *D* for varioustransmission frequencies is shown in Table 7-1.Where the transmission frequency lies between thefrequencies quoted, the approximate value for *D* maybe estimated. For example, for a transmission frequencyof 6.8 Mc/s, the distance *D' would'be estimated as35 feet (10 metres). Where a range of transmissionfrequencies is to be used, it will usuallybe best to selecta value of *D* corresponding to the lowest frequency.Aerials should have a length not much less than *D\ orlonger than twice *D*.

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Long Wire AerialF ig . 7 -1

Frequency Distance »D"Megacycles Feet Metres

2-5 94 293 81 243-5 67 204 61 184-5 54 165 47 14*6 40 127 34 •108 31 99 27 8

10 23 712 20 614 17 516 15 4 * '18 13* 420 12 3*-J 2

Table 7-1

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PART 2

T E C H N I C A L I N F O R M A T I O N

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Section

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PART: 2C O N T E N T S

Page. 9 D E S C R I P T I O N O F T H E R E C E I V E R . . 4 29 . 1 G e n e r a l 4 29 . 2 T h e L o c a l O s c i l l a t o r 4 29 . 3 T h e I . F . A m p l i fi e r 4 29 . 4 T h e D e t e c t o r . . 4 39 . 5 m B e a t F r e q u e n c y O s c i l l a t o r . . . . 4 39 . 6 A u d i o O u t p u t S t a g e 4 3

1 0 R E C E I V E R V A L V E R E P L A C E M E N T D A T A 4 4

1 1 V A L V E C H A N G I N G 4 51 1 . 1 V I , 2 , 3 , 4 a n d 5 4 51 1 . 2 V 6 4 51 1 . 3 V 7 4 61 1 . 4 V 8 4 7

1 2 R E C E I V E R I F R E S P O N S E C U R V E . . ~ 4 9

• 1 3 R E C E I V E R A F R E S P O N S E C U R V E . . 5 0

1 4 R E C E I V E R L I M I T E R A C T I O N . . . . 5 1

1 5 D E S C R I P T I O N O F T H E T R A N S M I T T E R 5 21 5 . 1 G e n e r a l 5 21 5 . 2 T r a n s m i t t e r A e r i a l M a t c h i n g . . . . 5 3

1 6 T R A N S M I T T E R V A L V E R E P L A C E M E N T 5 4

1 7 S I D E - T O N E O S C I L L A T O R T R A N S I S T O R 5 4

1 8 P O W E R S U P P L Y 5 5

1 9 S I D E - T O N E O S C I L L A T O R . . . . 5 61 9 . 1 G e n e r a l . , * . . 5 61 9 . 2 S i d e - T o n e O s c i l l a t o r G r o u p B o a r d . . 5 61 9 . 3 S i d e - T o n e O s c i l l a t o r C i r c u i t . . . . 5 7

2 0 B L O C K D I A G R A M S 5 82 0 . 1 R e c e i v e r . . . . . . . . . . 5 82 0 . 2 T r a n s m i t t e r 5 8

GONFIDftiTiAL

40

TP82 25

7%2 F ig . 7 -2 shows the reduced t ransmiss ion f romCont. a short aerial.

Transm i t t e r

V "

132/7-2

Short Wire AerialF i g . 7 - 2

Figs. 7-1 and 7-2 show the radiation fromstraight wires. Frequently it will not be possible toerect a sufficient length of straight wire to obtainadequate radiation and the wire must be bent.

eOfflBEHIIH

TPa2 26

7.2Cont.

Aerial in RoomF ig . 7 -3

Fig. 7-3 shows how a wire of length slightlygreater than 'D* may be taken round the walls andceiling of a room. Maximum transmission occursfrom the vertical wire to the left, with less transmissionfrom the wire along the ceiling and opposite wall. Therings on the aerial as well as showing transmissionstrength show that the vertical wire sends signalstowards the horizon whereas the horizontal wire sendssignals upwards and sideways.

WIOEHTHl

CONFIDENTIALT P 8 2 2 ?

7.2 Looked at from near the end of the wire, radiationCont. would appear as in Fig. 7 -4.

^ ' ^

Hor izonta lA e r i a l

Ve r t i ca lA e r i a l

J82/7-41

Aerial RadiationsF i g . 7 - 4

This diagram looked at in conjunction withFig. 7 -3 shows how vertical parts of the aerial tendto send signals towards the horizon whereas the horizontalparts of the atrial tend to send signals towards the sky.Running the aerial wire alongside metal pipes, electriccables or similar objects should be avoided astransmission may be spoilt.

f ^ 7 . 3 D i r e c t i o n o f T r a n s m i s s i o n

To obtain the most efficient communication betweentwo stations, it is not only necessary that signals besent in the right direction, for example South-East, butalso - depending upon the range of transmission - theyshouJd be sent at a low anglo towards the horizon or ata high angle towards the sky.

Fig. 7-5 show? roughly the paths taken from atransmitter to receivers situated 80 km (50 miles),500 km (300 miles) and 3000 km (2000 miles) away.It cAa be seer, that .vinnals should be transmitted at a

' i : ' ! i \ ;

/ ^ j k

pn<i ' 1TIU

TP82 28

7#3 low angle (towards the horizon) if they are to reachCont. a receiver 80 km (50 miles) away. The same signal

unfortunately will fade out before reaching the receiver3000 km (2000 miles) away.

To reach the second receiver 500 km (300 miles)away, signals must be sent high into the sky (high angle)where they are sharpely reflected down again to therece iver.

Finally to reach receiver No. 3 at a very greatrange (3000 km, 2000 miles), the signal should betransmitted at a lower angle (towards the horizon).

Reflecting Layers in Sky

\

Fa.a«sout

i ^ r » : . ~ ~ 2 n d R e c e i v e r ^ « J ? i / j * r1 s t R e c e i v e r . ^ S < * a <

' < * >/

laI/7-5

J y ^ \ „ « m R a n g e : s O O k m% - * R a n g e : 8 0 k m »■ • & / « - / % i - \ ( 3 1 2 m i t e s )& < C * V ( 5 0 m i l e s )

3rdRange: 3000km

Transmission Paths (1872 miles)F ig . 7 -5

= T i 4 I. i i o U

CQKriOENML

TP82 29

7,3 This information, together with that containedCont. in previous sections, enables the user to arrange an

efficient aerial where space permits. There will bemany circumstances where the space available is muchsmaller than appears necessary to accommodate thewire. In such cases, the total length o£ wire shouldstill not be much less than *D*, the spare wire at theend of the aerial being run backwards and forwardsacross a wall or ceiling. Typical aerials for usein difficult conditions are described in section 7 .6.

7.4 Aerial Planning

The following procedure is recommended:-

1. Refer to Table 7-1 and ascertain the distance *D*corresponding to the lowest frequency to be usedfor transmission.

2. Knowing the range of communication, consider theimportance of obtaining transmission at lowangle (vertical wire) or high angle (horizontalwire) - also direction of transmission (fromside of horizontal wire).

3. Examine the various possibilities of erectingaerial wire of length between *D* (or slightlyshorter) and twice *D' having required transmissiondirection and angle.

4. Establish the best available earth system (see section 7.8 ).

5.. Using the available wire, connect the earth and erectthe aerial.

liiMhSfSM

C8-MEHTIU

TP82 30

7»5 Use of Insulators

The plastic covered wire supplied is insulatedand, where string is used to attach the aerial to itssupports, no further insulation is necessary. Wherethe end of the aerial wire is to be supported byanother wire or metal object, use one of the egginsulators provided or interpose a length of string.The method of inserting an insulator may be seen inF i g . 7 - 6 . / ^ k

A e r i a l Support"Wire

82/7*6 Egg InsulatorF i g . 7 - 6

7-6 Other Accessor ies

When aerials have to be rigged and dismantledfrequently, there are two useful accessories whichmay be purchased locally. One is a crocodile clipfor connecting aerial and earth wires temporarily.The other is a hook with a suction cup which is usefulfor retaining an indoor aerial to doors, windows,picture rails etc.

BGSflOEHTIJIl ^ \

TP82COHflOWIJIl

31

7 . 7 A e r i a l L a y o u t s

The following diagrams illustrate how to overcomethe inconvenience of installing long aerials:-

7.7.1 Aerial in Room

/0p\A e r i i l \ . w . g t h ' C

E a r t h To mains .-.ocket

i_.ocnti.ur. Highest w:. il.-.Y..■*room .- ;>.«• -izkin basement ovc e l l a r

• Radio.tioa Mostly I-'.v/ -angle,some Mi;h

M a i n s S 3

Aerial in RoomF i g . 7 - 7

/0W\

Aer ia l -

A e r i a l

E a r t h

Length *D* org rea te r

Counterpoise

Locat ion H ighest ava i lab leroom - no usein basement orc e l l a r

Radiation Low and high angle,more high anglethan in Fig. 7-7

FtTr-H Mains

Aerial in RoomF i g . 7 - 8

/fffi£\

'»',:

TP82 32

7.7 The t ransmiss ions f rom the aer ia ls shown inCont. Figs. 7 -7 and 7 -8 will vary with the position of

the room in the building. The transmission fromrooms on the upper floors will be greater than thosefrom rooms on the ground or lower floors.

7.7.2 Aerial in Loft

A e r i a l

N o t e ; B yincreasing lengthof aerial wheredotted, high angleradiation may beincreased.

/*%

A e r i a lEar thLocation

Radiation

IE/7-9

Length 'D*Wire to central heating pipeSet ia any room, aerial in

lo f tGood low angle, moderate

high angles better thanFigs. 7-7 & 7-8 j

Aerial in LoftF i g . 7 -9

TP82CONFIDENTIAL

7.7 7.7.3 Aerial attached to Set in BasementCont,

33

Aerial Wire on outside wall of house,length o! -*-ire outride it

"n* or greater£»rth E>irth pin in groundLocation Set in So*e—ent or cellar

ltift-io] Radiation Low angle

Aerial to Set in BasementFin. 7-10

With the transmitter situated in a basement room,the best plan is to run a vertical aerial up the wall ofthe building with the aerial and earth wires runningclose together below the ground level as shown inFig. 7 -10. When the building has a television aerialinstalled, the down lead and aerial may be used. Thecoaxial plug should be disconnected from the televisionreceiver and the outer metal of the coaxial cablejoined to the transmitter aerial terminal.

In an emergency, metal roof guttering may beconnected to a wire down lead and used as an aerial. Thedown pipe is usually not much use in this respect as thesections are not usually properly joined together.

GOHFIOEHTIALTP82

7.8 The Earth

The performance of an excellent aerial may bespoilt if the set is used with an inefficient earth. Theearthing of a radio transmitter differs from the earthingof domestic electric appliances where earthing isnecessary to protect the user from the risks of receivinga shock.

The most efficient earth comprises a large metalobject buried in moist ground. The earth pin providedwith the set will serve this purpose and should bejoined to the earth terminal on the set by a short wire. . )It may not be possible to achieve this ideal and thefollowing are recommended:-

(i) connection to the cold pipe of a water supplysystem provided metal piping is used,

(ii) connection to the earth wire of the electricsystem. Such an earth wire is usuallypresent only where 3-pin plugs are in use.

In the event of the recommended earths not beingavailable, and space permits, a 'counterpoise* earthmay be used. The counterpoise earth should comprisea wire of length 4D* at the working frequency. Wherea range of frequencies are used, *D* should be chosento correspond to the lowest frequency of the range. Thecounterpoise wire should be connected to the earthterminal of the set and stretched out as far as possiblefrom the aer ia l wire. I f space does not permit the '^ jcounterpoise earth to be placed in a straight line, it maybe bent in the same manner as the aerial, see Fig. 7 -8.

If none of the foregoing prove practical, any accessiblemetalwork - such as central heating pipes or a metalbuilding frame - may be used as an earth. The contactbetween the earth wire and metalwork - i.e. pipe,radiator etc. - should be a bare metal to metal joint.Connection to a gas system is not recommended as thereis some risk of causing a fire.

CONFIDENTIAL

T P 8 2 3 5

7.8 Finally, where the transmitter is employedCont. with the mains power supply, the connection to the

mains provides some degree of earthing and willpermit transmission in the event of nothing better .being available. In this event, it is not necessaryto make any connection to the earth terminal of thetransmitter.

/ ^ \

GOSFiOENriU

CONFIDENTIALT P 8 2 3 6

8 F A U L T S A N D R E M E D I E S

8 . 1 G E N E R A L

Symptom: Set does not appear to function at all.

»„&; .

1. Check fuses in mains plug adaptors -there is one fuse in each lead. Replace,if necessary, with 15A fuses suppliedwith the spares.

2. Check fuse located on the underside of theset. Replace, if necessary, with a 4Afuse supplied with the spares.

3. Check pins on mains plug adaptor - theyshould be screwed up finger tight.

4. Check that the mains voltage tap switch(No. 21) is set correctly. Confirm voltageof mains supply with a meter or the neontester.

5. Check that all connections are secure.

6. Check that the headphone jack plug is pushedright home.

7. Check that the small plugs that join the headphoneleads to the earpieces are seating correctly.

8 . 2 R E C E I V E R

Symptom: A hiss is heard in the headphone's, but the stationsare not audible:

Remedy: 1. Check other wavebands to see if the fault ispresent only on one particular band.

2. Check the aerial.

GUNflDENTJAL

COflflDWIAL

TP82

8 . 2 S y m p t o m ;Cont.

37

Broadcast stations are audible but no morsesignals.

J$PG\

igp\

Remedy: 1. Listen for the extra noise which should bepresent when the BFO switch (No. 2) issv/itched on. If no change in noise levelis heard, suspect the BFO.

Symptom: Reception is weak after the equipment hasbeen stored for some time:

Remedy: 1. Check the aerial connections.

2. Check the mains voltage setting.

3. The electrolytic condensers may requirereforming - see section 5.3.

Symptom: If nothing is heard, not even a hiss.

Remedy: 1. Follow procedure shown in section 8.1.

2. Check that the valve retainer on VI is notshorting the HT to the BFO switch.

3. Check that the valve retainer on V3 is notshorting to the output jack socket PI.

4. Chock the HT, using a meter or the neontester.

5. With the cover remove.d, check that thestabilising valve V3 *strikes* when the setis switched (No. 11) to 'receive' position.

Valve changing should not be attempted until all the abovemeasures have been taken. Valves VG and V8 require workshopfacilities and changing them in the Field is not practical.

CONFIDENTIAL

CONFIDENTIAL

TP82 38

8 . 3 T R A N S M I T T E R

Symptom: The neon tuning indicator does not glow.

Remedy: 1. Follow procedure shown in section 8.1.

2. Check that the receive/transmit switch(No. 11) is switched to 'transmit*.

Symptom: The neon tuning indicator remains dull - doesn o t g l o w t o f u l l b r i l l i a n c e . * j

Remedy: 1. Check for a faulty crystal by trying asubstitute.

2. Check that the correct waveband is beingused.

3. Check that the morse key is 'down .

4. Change valve VI, using the 5A/163K valvesupplied with the spares.

Symptom: The neon tuning indicator lights satisfactorilybut the output meter fails to operate.

Remedy: 1. Replace valve V2 with CV428 valve suppliedwith the spares.

Symptom: The neon tuning indicator lights satisfactorilyon tuning up, but fails to strike on subsequentkeying.

Remedy: 1. Detune the drive (No. 15) - see section 6.2.8,

CONfiOEKTUL

/ ^ S

CONriOENTIAL

T P 8 2 3 9

8.4 OVERHEATING OF THE EQUIPMENT

When the equipment is grossly overheated,smoke and/or an odour is usually apparent.

SWITCH OFF IMMEDIATELY

j ^ \There are three main types of odour:-

8.4.1 Smell of Burning RubberIf the aerial is grossly mis-matched, power

will be dissipated in the aerial coil and the PA -valve - and these two items will overheat. Sincethe valve is surrounded by rubber, a distinctivesmell is produced. Check that the aerial isstill connected to the equipment, retune the transmittertaking special care over the aerial matching and,if still overheating, lengthen the aerial in an effortto obtain more efficient transfer of power into it.

3.4.2 Smell of 'Rotten Eggs*A most unpleasant and unforgettable odour -

produced when the rectifiers have overheated asa result of, usually, a faulty electrolytic condenseror other HT short to earth. Replacement of therectifiers will be inevitable and tracing of theoriginal fault is necessary before switching onagain. A rectifier failure can also lead to asmell of hot varnish,

8.4.3 Smell of Hot VarnishCaused by an overheated mains transformer

and is sometimes accompanied by heavy blacksmoke. Replacement of the mains transformer -requiring workshop facilities - is usually necessary.Do not switch on until the original fault has beenfound and corrected.

Overheating of the means transformer can alsobe caused by a grossly incorrect voltage tappingor by inadvertant insertion of the equipment intod.c, mains supplies.

CO/ifiiJEliTML

o

o

(1

TP82

/gp\

Section

2 i

23

i<->

39.129.22'*.329.429.529.6

3030.1VJ.lSO.'J30.450.5

.113 i. J31..?31.3/1*51.931,10

GONFiDEHTt&L

C O N T E N T S(Continued)

LOCATION OF COMPONENTS . .Dust cores, trimming condensers &Receiver Components . . . ,

RECEIVER PARTS LIST

RECEIVER CIRCUIT.DIAGRAM. .

TRANSMITTER PARTS LIST . .

TRANSMITTER CIRCUIT DIAGRAM

POWER PACK PARTS LIST

POWER PACK CIRCUIT DIAGRAM

CONDENSER RE-FORMER CIRCUIT

RECEIVER TEST PROCEDUREEquipment RequiredAF Gain . .IF GainIF BandwidthB .F.O .RF Sensitivity

41

TRANSMITTER TEST PROCEDUREEquipment RequiredOscil lator AlignmentAtrial Tuning MeterPower Output . .Voltage and Current Measurements

POWER UNIT TEST PROCEDUREEquipment RequiredTest Procedure . .Current and Voltage ReadingsS ide -Tone Osc i l l a t o r . . . .Insulation . .

Page

59v a l v e s 5 9

60

61

64

65

67

68

69

70

71717171727272

7 4747 4747 475

777777787979

EHTIJL

C O N F I D E N T I A L 1T P 8 2 4 2

9 D E S C R I P T I O N O F T H E R E C E I V E R C I R C U I T

9 . 1 G e n e r a l

The receiver is a superheterodyne. The aerial isused both by the receiver and the transmitter. When theswitch (No. Ii) is toward the receiver, the aerial isconnected to the tuning coils LI, L2 or L3 - according towhich waveband the switch (No. 1) is set. The signal isamplified by VI and then passes through a second stageof tuning L4, L5 or L6 - the primaries of which aredamped by R2. The local oscillator signal is injecteda t t h i s p o i n t . ^

9.2 The Local Oscillator

The local oscillator is of the tuned-grid type, g2 ofV5 being used as the oscillator anode. L7, L8 and L9 arethe oscillator coils. They are fitted with dust iron coresand adjustable trimming condensers C33, C34"and C35.The fixed padders are C32, C36/37 and C56. The oscillatorHT voltage is stabilised by C46 with C31 as the RF bypasscondenser. The local oscillator is at a higher frequencythan the signal.

The local oscillator is electron coupled by the anode ofV5 and is applied to the anode of VI, where it is fed into thegrid of V2 the mixer valve, via the tuning circuits L4, 5 or 6.

9.3 The I .F. Ampl ifier

After mixing, the intermediate frequency of 465 Kc/s i?*%applied to the IF transformer IFTl which is tuned to 465 Kc/S.The signal is amplified by the IF amplifier valve V3 andthen applied to the second IF transformer IFT2. C20 andC2I are neutralising capacitors giving the high gain IFamplifier a greater margin of stability.

CONFIDENTIAL

^

CONFIDENTIAL

T P 8 2 4 - 3

9.4

0 ^ y

The Detector

V7 is the detector diode valve and at this point theBeat Frequency Oscillator voltage is applied from V6to make c.w. signals audible.

9 .5 Beat Frequency Osc i l la tor

The B.F.O. is of the electron-coupled Colpitts typeand is coupled to the signal detector through a capacitorC40. The core of the inductance L10 is adjustable asin the IF circuits and a variation of several kilocyles -above and below the intermediate frequency is obtainedby the variable condenser C47 which is under the controlof the operator (No. 3). Switch No. 2 on the front panelis the BFO on/off switch.

9.6 Audio Output Stage

After being rectified by the detector V7, the signalpasses through the IF filter C25, R15, C26 to remove anyremaining IF frequency of 465 Kc/s. R14 is the diodeload. The audio signal is then amplified by the valve V4and is applied to the earphones via the miniature jacksocket PI. Diodes Wl and W2 are crash limiters, that is,they reduce the amplitude of crackling, switch noises etc.,and so protect the ears. The condenser C54 is to reducethe intensity of the very high frequencies, and preventradiation of the IF via the phone leads.

COHFIOENTfAl

CONFIDENTIAL

TP82

10

4 4

RECEIVER VALVE REPLACEMENT DATA

Valve B r i t i s h Br i t i sh U.S. Base ConnectionsServices Commer. Equiv.

V I ^ ix.V3 •V5

CV465 EF72 t_ —

2.4.6>p^Pentode [ I B8D/F

4 i a

V2V4 CV466 EF73

i

\ xp

Pentode l^ ? y B 8 D / FA « .

1 I 5V7 CV469 EA76 A \Diode * T H B 5 B / F

a.4-,7

V8 CV4052 QS1202 6n>Stabil iser 7C b7g/f

•

CONFIDENTIAL

TP82

I I

CONFIDENTIAL

VALVE CHANGING

45

11.1 VI, V3 fc V5V2 Sc V4

Pentodes (Spare: type CV465)Pentodes (Spare: type CV466)

1.

2.3.

4.

5.6.7.

Remove the six Parker Kalon screws holdingthe case.

Remove the case.With the small screwdriver or pliers provided,

push the C-shaped retaining clip to one sideand then remove the valve.

Before fitting the replacement valve, make surethat the valve pin wires are cut to the correctlength - 3/l 6 in. + l/32 in. - and that they areperfectly straight by using the B8D pin aligningtool. This process is illustrated below.

Replace the valve.Replace the retaining clip.Replace the cover and secure with the six retaining

screws.

cut here Valve in Aligning Tool

11.2 V7> B.F.O. Valve (Spare- type CV466)

This valve is situated inside the BFO unit and it isnot recommended that any uttempt be made to change itunless full workshop facilities are available.

If possible a complete replacement BFO unit shouldbe fitted.

G0NF10ESTUL

CONFIDENTIAL

TP82 46

11.3 V7 Detector Diode (Spare: type CV469)

1.

2.3.

4.

5.

6.

7.8.

9.10..

11.12.13.

14.

Remove the six Parker Kalon screws holdingthe case.

Remove the case.Remove the four 2BA Phillips-headed screws

on the back of the receiver.Remove the three 4BA Phillips-headed screws

on the back of the receiver.Disconnect the earth (black) wire joining the

power pack to the receiver.Disconnect the six wires joining the power pack

tag strip to the receiver tap strip.Remove the receiver.Push condenser C25 (on the IF transformer IFT2)

on one side.Remove valve V4.Unsolder the two yellow V7 wires from the 3-way

tag strip tag 5. See drawing below.Unsolder the valve green wire from pin 3 of V4.Unsolder the black wire from chassis E.Lift the valve retainer and remove V7, drawing the

two yellow wires and the green wire throughthe hole in the chassis.

Remove the sleeving from the old valve and replaceon the new valve.

Green Pin 1 ^ y C j x *Yel low Pin 2Black Pin 3 yC y^Black Pin 4Yel low Pin 5 Base of Valve

SaSFIOtXTIJSt

TP82

CONFIDENTIAL

47

11.4 V8 Stabi l is ing Valve (Spare: not provided)

1. Remove the six Parker Kalon screws holdingthe case.

2. Remove the case.i. Remove the four 2BA Phillips-headed screws

en zh.e back of the receiver.4. Remove the three 4BA Phillips-headed screws

on the back of the receiver.5. Disconnect the earth (black) wire joining the

power pack to the receiver.6. Disconnect the six wires joining the power pack

tag strip to the receiver tag strip.7. Remove the receiver.8. Remove the three 4BA mushroom-headed screws

from the centre of the bottom plate holdingthe gang condenser.

9. Remove the seven 6BA 3/l6 in. mushroom-headedscrews from around the edge of the bottom plate.

10. Remove the bottom plate.11. Unsolder the two earth connections to the trimmers

at the trimmer end.12. Unsolder the condenser and wires on the rear gang

section (BFO end).13. Remove valve V2.14. Tuck the three PVC wires out of the way of the

soldering iron.15. Unsolder the middle section and front section of

the gang condenser, taking care not to mix upthe wires on re-connecting.Middle section: one yellow wire to mixer switch,

one yellow wire to C17, V2 pin 1.Front section: one yellow wire to* osc. switch.Leave the yellow wire on the front section thatgoes to the condenser.

16. Unsolder the red wire, front of the tag strip whichgoes to V8 pin 5.

17. Remove the tuning condenser assembly by unscrewingthe two 6BA fin. screws above the dial, takingcare to note the position of the two washers underthe dial block.

COSFIOEJimL

CONFIDENTIAL

T P 8 2 . 4 8

11.4 18. Remove the two 4BA Phil l ips-headed screwsC o n t , u n d e r t h e b l a c k v e r n i e r k n o b .

19. Withdraw the gang assembly from the front,taking care not to trap any wires.

20. Remove the condenser from the front.gang C16tc obtain access to ^he earthing tag.

21. Unsolder the valve base wire with the blacksleeve from the condenser frame (extra heatfrom a larger iron may be necessary tounsolder the earth joint to frame).

22. Prepare new valve hy removing base wires1, 2, 3, 6 and 7 completely.

P u t b l a c k s l e e v i n g o n N o . 4 jExtend No, 5 to 2 inches (5cm) long with

tinned copper wire 26 swg and sleevewith red sleeving.

23. Replace the valve in spring retainer with black(pin 4) lead nearest to the point of earthing.

24. Make earth joint to condenser frame.25. Replace condenser (C16).26. Repeat operations as above in reverse order.

G0NF10EMT1AL

CONFIDENTIAL

TP82 49

12 RECEIVER I.F. RESPONSE CURVE

■

1 o

\o

?n

4

ao

. 4 0

'

SO

11

d&

- 1 5 - I O - S OKc/s

l O 1 5

CONFIDENTIAL

CONFIDENTIAL

'[ P82

13 RECEIVER A.F. RESPONSE CURVE

50

[H73

Curve A: AF ResponseInnut to IF Filter

I A

Curve Bi Overall AF Response

y*

i

Input to Aerial•

\,

\ !

1 [i i\!

i

\ i- \

1\ *j

\

*

/ \ !t

<Ar

!

/V

| \iit

/

f,

Ji ji i l

.. .

..—

• 1 /^

— j ...i

i

}1

ti i\ 1%» t o o 1r :i *I !i i» •r a 9 l ° < K » •i at *t tr <: i a » u

:-~*ao<£««*£Y

ifl,1f!B£NTIJlt

TPR2CONFIDENTIAL

51

RECEIVER LIMITER ACTION

oooo"

o

3a.30

AF Input to TP2: at 1 Kc/s 0db=10 volts

CONFIDENTIAL

CONFIDENTIAL

T P 8 2 5 2

15 DESCRIPTION OF THE TRANSMITTER CIRCUIT

15.1 General

The transmitter will operate between 2.5 and 20 Mc/sin the following wavebands:-

Band 1 2.5 to 5.0 Mc/sBand 2 5.0 to 10.0 Mc/sBand 3 10.0 to 20.0 Mc/s

Valve VI is a pentode performing two functions - thatof oscillator and doubler. The oscillator electrodes aregl, g2 and cathode connected in a type of crystal controlledelectron-coupled Colpitts circuit. Condensers C2, C3 andC4 are the feed back capacitors.

When the morse key is depressed, the bias is reducedthus bringing the crystal controlled oscillator into action.The capacitors C18 and CI and resistor R2 are key clicksuppressors.

The coils LI, L2 and L3 are switched by S1A (No. 12)and tuned by the variable condenser C9 (No. 15) and thesetwo controls can be tuned either to the fundamental or tothe second harmonic (i.e. with a 4 Mc/s crystal, tuneeither to 4 Mc/s in Band 1 or to 8 Mc/s in Band 2),

The Neon LP1 (No. 13) is a resonance (or tuning) ^indicator for the drive frequency and glows to a maximumon tune.

The oscillator voltage is amplified by the poweramplifier (P.A.) output valve V2. The resistor R9 andchoke L4 are to suppress parasitics. After amplification,the signal has to be matched to the aerial so that themaximum power may be radiated. This is done by theanode tank coils L5, L6 and L7 tapped by switch S2 (No, 18)so that the aerial is properly matched. The coils aretuned by the variable condenser C13 (No. 17).

f-fcifiGEHTlJi.

CONFIDENTIAL

T P 8 2 5 3

15.1 The meter Ml (No. 14) is the aerial voltageCont. meter and part of the output is tapped off by the

condenser divider C15 and C14, then rectified byRCT1 and smoothed by the RF filter condenser Cl6.

RCT2 provides an approximately logarithmicmeter indication and is temperature compensatedby Brimistor R-13.

S j ^ 1 5 . 2 T r a n s m i t t e r A e r i a l M a t c h i n g I m p e d a n c e s

The aerial impedance matching switch has fourpositions and will match into the following loads:-

Ta p 1 O p t i m u m L o a d 2 5 o h m sTap 2 Opt imum Load 100 ohmsTap 3 Opt imum Load 500 ohmsTap 4 Optimum Load 1,500 ohms

CONHOENTIM

GOSfiOENTIAl

TP82

16 TRANSMITTER VALVE REPLACEMENT DAT.A

54

Valve B r i t i s hServices

Br i t ish j U.S.Commer.J Equiv,

Base Connections

. V i

HFPentode

CV1635

! .*a/ i6-*k t ( £ \■ i i

2

7.B

i

4 5 B9A

V2

BeamTetrode

. .. — ...

CV428 5B/251M5B/254M * g . - 1 j j |

, i B S G j1

17 SIDE-TONE OSCILLATOR TRANSISTOR REPLACEMENT DATA

Valve Br i t ishServices

Br i t i shCommer.

U.S.Equiv.

Base Connections

VT1

Trans is tor

CV2400 I OC71

i_LI o • a ST,

CGSFIOENTiiL

TP82

18

CONFIDENTIAL

POWER SUPPLY

55

Mains Power Supply

The Power Supply will operate ONLY from a.c.supplies. The transformer is tapped at the voltageslisted below.

Power Input Voltages, Current and Watts

50 c/sInputVolts

Receiver only TX unkeyed TX keyedAmps Watts Amps Watts Amps Watts

100 .44 31.5 .41 28.5 .92 83

110 .39 32.5 .36 29 .82 85

120 .37 33.0 .34 29 .76 86

130 .35 ' 33.5 .32 29.5 .72 88.5

140 .33 33 .30 29.5 .67 88

150 .30 32.5 .28 28.5 .62 86

200 23 33 .22 29 .48 89i

210 .22 33 .*« 29.3 .4b 39.5

220 33 .20 29 • 89

230 .20 33 , .9 >9 5 .43 89

240 .20 33 .18 29.5 .41 88

250 .19 32 .18 291

.40 90

CCMDEHTIAL

CONFIDENTIAL

TP82 56

SIDE-TONE OSCILLATOR

19.1 General

The side-tcr^ cricilUior provides an audible notein the operator's headphones when the transmitteris keyed.

It consists of a single stage transistor oscillatorwhich derives its d.c. supply from the transmitterbias network. Reference to the circuit diagram shows,that the transmitter bias is obtained from the voltagedrop across the two resistors R3 and R4.

The voltage across R3 is negligible when thetransmitter is unkeyed but rises to approximately14 volts when keyed. This voltage is applied to theside-tone oscillator (connections A and B) and producesapproximately 2 Kc/s tone, which is fed to the receiverheadphones via connection C,

19.2 Side-Tone Oscillator Group Board

R T 2 R T l

^

c t

%• I I' » 1

P L - JC 2

; ;i

C3

*2 , .R4P i / /m IrTi

CUD

-5* <PIKSO

*A' YELLOW

• EA2TH

-*C' WHITE.

The group board is situated in the power supplysection of the Mk. 123. Connection^ A, B and C connectto points A, B and C en the power pack.

nmr i

CONFIOEHTItt

TP82 57

19.3 Side-Tone Osci l lator Circuit

RTJ

RT.2

Rl Resistor 4.7 Kohm + 10% Erie Type 16 R16/247KR2 Resistor 15 Kohm + 10% Er ie Type 16 R16/315KR3 Resis tor 10 Kohm * 10% Er ie Type 16 R16/310KR4 Resistor 1.5 Kohm + 10% Erie Type 16 R16/215KR5 Resistor 470 Kohm + 10% Erie Type 16 R16/447K

CI Condenser .1 /uF +_ 25% Dubi l i fcr 412 CT101DC 2 C o n d e n s e r . 1 / i F + 2 5 % D u b i l i e r 4 1 2 C T 1 0 1 DC3 Condenser 8 pF +50% -23% TCC 68A/D CE8TP/W

RT1 Miniature Westector Type WRT2 Miniature Wesfcector Type W

RT6ART6A

V I

T l

Transistor OC71

Transformer

RT222

TL368

COSHDEHIIAI

CONFIDENTIAL

TP82

20 BLOCK DIAGRAMS

58

20.1 Block Diagram - Receiver

I j *•*AMP.

1 FMIX.J"osc.

VOLT AG E.

S TA & I L I S E J ?

uI F - 5 — I D £ T.■ 8

AUDIOAMR

CRASHLIM. - f b

—■— ib-F.O. / ^ .

20.2 Block Diagram - Transmit ter

C R Y S T A LC O N T R O L L E DO S C I L L AT O R

powera m p l i fi e r

i y

■,s»»;r:n.r*;rt*i

TP82

21

59

LOCATION OF COMPONENTS

21.1 Location of iron dust cores, trimming condensers andva1ves

%

2®Z.7.

® !1i

®MIX.

(e)

<§)osc.

®utt/ai. I'

T T

■ I f v n iV ^ i

. . /• :^ l•vAw

MIX. 2^-Q) i

OSC 3 (g ) |I

63) 2*S5*t?

B.F-O.

MB}1

o o 0o <^> o

o o ©

L J

V7

I F.T.I

tF.T2.

V fi V 54-.• i -• •

VI e

idP*V6—

U545 • •

1 - 11

RECT -—2

/&

/ R X j \ P O W E R PA C KV 7 V 4 V 3 V 2

<£2-

TXV 2 V I

WFSESfUl

TP82SONtiOENTiAl

21.2 Receiver Components

60

C33 14

C

©® (D©®©U»M*R CU*B*»*

i GAMG

CI.C2.C3

i- ' f J 'J I /O. F^~ —J /\£32-arLi C j ' u « \ { / J V ^ *

23

*, i»

ci i

IffCS6

C 2}l e i jnLl

vTft^ElsJ"<JlM2\ - -, -

Tv rUKtMLR CHASSIS

ijp^«

TP82

CONFIDENTIAL61

22

C i r c u i tRef. No.

RECEIVER PARTS LIST

v aiue

RRRRRRRRj>R

123456789

10R 11R 12R 13R 14R 15R 16R 17R 18R 19R 20R 21R 22R 23R 24R 25R 26R 27R 28R 29R 3DR 31R 32

3.910

1 .1805

82147

1470

118047470

1470100470273322150220100

11001033470

KojamsKohmsKohmohmsKohmsKohmsMohmKohmsKohmKohmsKohmohmsKohmsKohmsMohmKohmsKohmsohmsKohmsohmsKohmsKohmsKohmsKohms

MohmohmsKohmsKohmsohms

j,; i l> C I i j/ i, 1 o

l/4watt +10% Erie type 16l/4watt+10% Erie type 16l/4watt+10% Erie type 16l/4watt+10% Erie type 162 watt potentiometer Painton C V2l/2watt+10% Erie type 9l/4watt +10% Erie type 16l/4watt +10% Erie type 16l/4watt+10% Erie type 16l/4watt +10% Erie type 16l/4watt+10% Erie type 16l/4v/att +10% Erie type 16l/4watt+10% Erie type 16l/4watt +10% Erie type 16l/4watt+10% Erie type 16l/4watt+10% Erie type 16l/4watt+10% Erie type 16l/4watt +10% E*ie *yPe 16l/4watt+10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie *yPe l&

l/4watt +10% Erie type 16l/4watt+10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie type 16l/4watt +10% Erie type 16

Stores Ci rcu i tRef. No.

•239-

Location

R l 6 - •K B4R l 6 -■310- K D4R16-•210-•K B5R16-•118-■K F5RW-35-F» F5R9-382-K E7R16-•510-•K F8R16--347-■K B8R16--210--K B9R16--447--K E10R16--210--K B l lR16--148--K F l lR16--347--K D13R16--447.-K F14R16 -510-: K F15R16 -447-- K B15R16-410 - K B15R16 -147 - K F15R16 -327 - K J2R16 -033 - K H7R16-322 - K FR16-415 - K H13R16-422 - K H14R16-410 - K J14

R16-510-K F4R16-110-K F8R16-310-K K13R16-333-K F4R 1 6 - 1 4 7 - K E l l

bUflfluthiiilL/ R>

CONFIOENML

TP82 62

22Cont.

CircuvuRef; No. Value

C 1 IC 2 i ; 200 pFC 3C 4c 5 1L 5-30 pFc 6 Ic 7c 8 .001 uFc i .001 uFc 10c n .1 uFc 12 Irc 13 { 5-30 pFc 14 <t

c 15 4 pFc 16 10 pFc 17 100 pFc 18 .001 uFc 19 .001 uFc 20 750 pFc 21 1.5 pFc 22 .01 uFc 23 .01 uFc ?A .02 uFc 25 100 pFc 26 100 pFc 27 .01 uFc 28 8 uFc 29 . ,005 aFc 30 .01 uFc 31 .005 uFc 32 .0013 u*

RECEIVER PARTS LIST (Continued)

D e s c r i p t i o n

3-gang tuning condenser Jackson

Erie Style 557N750

+20% Dubilier type 400+20% Dubilier type 400

+20% Hunts type W48

Erie Style 557N750

+ |pF Erie S±yle KA Gimmicon+5% Erie Ceramicon N750K+20% Dubilier type 400+20% Dubilier type 4C0+20% Dubilier type 400+ 10% Dubilier type S635+ l/4 pF Erie Style EKA Gimmicon+20% Hunts type W99 B810+20% Dubilier type 400+ 10% Plessey Piesmin+ 20% Dubilier type 400+20% Dubilier type 400+ 20% Dubilier type 400-25% -«-50% TCC type CE68A/D+20% Dubilier type 4C0 "+20% Hunts type W99 B810+ 10% Dubilier type 400+ 2% Dubilier type S635

Stores C i r cu i tRef. No. Location

F4C3200F F 8

J6F Z

CX430F F3F3

CT0013 B5CT0013 E4

CT101H/A F5C5

CX430F C6C7

C540D F6C410AJ F8CTOOl/ l E8CT0013 C9CT0013 C8CS375DK E10C515E D l lCT013J F l lCT011 F l lCT021P/K F12CT001/1 F13CTOOl/ l F14CT011 D14CE8TP/W F15CT0052 C15CT013J D16CT0052 K2CS213D/G K2

HAL ^^ij.

CONFIDENTIAL

TP82 63

Cont.RECEIVER PARTS LIST (Concluded)

/3S*\

J ^ s

j r r n %*Ke£. N(o. Value

C 33 f •

34 ( 5-30 pFC 35 (c 36 .0013 uFc 37 .0013 uF

38 1 00 pF£. 39 15 ??.-■* 40 3 pFv.. ■W 30 pFC 42 300 pFc 43 680 pFf ~ 44 .0013 uFr 45 10 pF*-• 46 8 uFC 47 20 pF max,C 48 .001 urC 49 .01 uFc 50 .001 uF/- 51 1 uFr* 52 .01 uF*c 53c 54 .001 i;F/■ 5b 15 pFC S6 .005 '.«F

D e s c r i p t i o n

Erie Style 557N750

+ 2& Dubilier type S63 5+ 2% Dubilier type S635+ 20% Dubilier type 400+ 5% Erie Ceramiccn N750K+ l/4pF Erie Ccramicon NPOK+_5% LEM type 1106 (insulated)+ 20% Dubilier type 400+ 5% LEM type 1106 (insulated)+2^ Dubilier type S635+ l/4pF Erie Style KA Gimmicon-20% +50% 150V wkg TCC type CWingrcve & Rogers type C31-14+20% Dubilier type 400+ 20% Dubilier type 400j_20% Dubilier iy}te 400+ 100^ -20% 50^ vkg TCC type C+20% Dubilier type 400

+ 20% Dubilier type 400+ 10% Eric- Ceramiccn N750K■i5% LEM type 2515 (insulated)

Stores Ci rcu i tRef. No. Location

J3CX430F J4

CS213D/GJ3K3

CS213D/G K 3CTCOl / l H6C415AJ J6C530D E ! 2CS430G/J J I 2CT 001/3 J15CM368L/J J15CS213D/G K15C410F/J J3F-C CE8T/QS K2CX421 J15CT0013 K13CT011 E 4CT0013 F5D CE1T F6CT011 F10

CT0013 E17C415AK F 4CS250G K 4

CDMErlJiAL

1

^

^

/jppSS

CONFIDENTIALTP82

2-*

C:i r c u i tRef. No,, Value

K I 39 KohmsP 2 100 ohmsr> 3 470 ohmsR ^ 3. 3 KohmsR 5 10 MohmsR 6 22 KohmsR 7 6.8 Kohmsr j 8 200 Kchmsft 7 47 ohmsR 10 19.5 Kohms

:; 11 -><-•2 Kohmsi> 12 68 ohms{ / 13 1, 5 Kohms«•; 14 1 Kohm.-.J? 15 560 ohmsR 16 180 ohmsR 17 18 KohmsK 12 18 Kohms

--/ ii 2 u FC ? 15 PFG 3 100 p FC 4 100 PF*C 5 330 p F/** 6 1500 p F<— 7 680 p Fr 8 .01 u Fi * 9 175 t j FC R» .01 u Fo 11 .01 a Fo 12 470 P f*».. 13 175 PFc 14 .5-3 PFQ 15 47 p F

65

TRANSMITTER PARTS LIST

D e s c r i p f i o n

i/2watt tl0% Erie type 9l/4watt +10% Erie type 16l/2v/att+10% Erie type 9Iwatt +10% Erie type 3l-jvatt +20% Erie type 8lwatt H0% Erie type 8lOwatt +10% V/elwyn A^'31112watt +10% Erie type 101/2watt +20% Erie type 92 Off 39Kohms in parallel +10%

Erie type 10l/4v.-att+10% Erie type 161/2watt +10% Erie type 9Brimistcr CZ3 +20% # 20°Cl/2watt +10% Erie type 9l/2watt+10% Erie type 92watt +10% Erie type 10i/2v.att +10% Erie type 9l/2watt H0% Erie type 9

1 £ 0 V pk v/kg T C C Ly p e 7 A12 F+ 5% Erie Ceramicon K750K+ 10% Erie Ceramicon K750L+ 10% Erie Ceramicon N750L+ 20% Erie Ceramic on K1200K»20% Eriff Ceran«icon Hi-KL• 2 0% Eric C'-rxmicor. KI-KKj"20% Hunts 350V ukn type W99 B810v«*ri«'ibl« V/ingr<,»vt.» L Rogers C8/C4TCC CP33S ^2!>% ?<j0V xvkgTCC CP33S J>5% 500V wkg1750V vt-fcg Erie type K120O/CD9variable V/ingrcve &: Rogers C8/C4Eric miniature tubular trimmer 3115A+ 10% Erie Ceramicon K750K

Stores Ci rcu i tRef. No. JLocation

R9-339K E2R16-110K G5R9-147K G6R8-233K C7R8-610M C9R8-322K G8R52-2681K C1.1R1C-420K G10R9-047K E l i

R10-339K C12R16-222K J16R9-063K H15R49-2F5M J14R9-210K J14R9-156K J14R10-418K G12R9-318K E 8R9-318K E8

CE2TG H5C415AJ E 6C310CK F6C3I0CK F6C333 D 7C2I5AM F7C368WM C9CT013J G9C117WS/A E9CTOSTS G10CTOSTS G13C347E D13C117WB/A G14CX530 J17

C447AK HJ7

CONFIDENT!*/jSPN

TP82

24Cont.

«:U i l f i» )L .? l lHL

TRANSMITTER PARTS LIST (Continued)

66

Ci rcu i tRof# ^!r Value

C 16 . 0 1 u FC 17 . 0 1 u FC 16 . 0 4 u FC 19 330 pFC 20

L iL 2L 3L 4L 5L 6L 7

Rect !Rect i

M 1

Key

D s s T i ^ t i o n

+ 20% Hunts 350V wkg type W99 BS10TCC CP45W 1000V wkg+20% 150V wkg Hunts type W99 B858+20% Erie Ceramicon K1200K2 turns of 24 swg tinned copper wire

Suflex sleeved wrapped round leadto coil

2.5 - 5 Mc/s5 - 1 0 M c / s10 - 20 Mc/s

'Parasitic Stopper2 . 5 - 5 M c / s5 - 1 0 M c / s10 -20 Mc /s

CG1E BTHSTC Uniplate H7

StoresRef. No.

C i r cu i tLocation

V t 5A/163KST&CV 2 CV428 ST&C

RFC1 415 uH 121-480RFC* 2.3 r n l t CH24ARFC 3 400 uK CG36RFC4

LP I

500 uH CH37

Hivac XC15

C T 0 1 3 J J 1 5CT019F/S G13C T 0 4 1 H G 4C 3 3 3 E 1 2

123-650 F8123-640 F8123-630 F9123-710 E l l123-670 G15123-680 G16123-690 G17

RT49 H16RT40 J15

CV1635 D65B/251M D12

F6.C6C l lF3

L P 9 5 A C 9

E8

S W 3 1 D G 1 5

Meter 0-500uA Hobut 400 ohms type FA M1500BA H14

2 1 7 - 2 7 0 G 4

3 pole 3 position: 2 pole shorting3 pole 4 position AB Metal Products

Minibank make before break

/ ^ \

Uji ir i j ifiiuL

l o t o I M I " » I o \ x i I

~MV L_%,_L■-th

h 1 — ; / '

f' WV ▶- —♦—|

AftM «

i n

C£OI

t o

2 :

J j i l .

T-.____. » I?:

CGNFiDENTttlTF\S2 68

26 POWER PACK PARTS LIST

Ci rcu i tRci'. Mo. Value D e s c r i p t i o n

S t o r e s C i r c u i tRef. No. Location

R 2R 3R 4R 5

C 1C 2 *C 3 *C 4 *C 5 f f

F I

T 1

S . !

S 2

P 1

Rect 1Rect I

TB ITS 2

2.5Kohms lOwau t 5% Wciwyn A\V3i 1110 Kohms Iwatt+10% Erie type 9

1 00 ohms 1 Owatt + 5% Weiv/yn AW 311127 Kohms 2watt +5% Erie type 1039 ohms 5watt + 5% Painton type P301

1 6 u F H u n t s J 3 4 0 5 K Z1 6 u F H u n t s J B 4 0 5 K Z1 6 u F H u n t s J B 4 0 5 K Z1 6 u F H u n t s J B 4 G 5 K Z1 6 u F H u n t s J 3 4 0 5 K Z

4 amp Bel l ing Lee No. L562

0-30-236 Transformer T420U

R52-225J C3R9-310K D4R52-U0J E l lR10-327J F l lR52A-039J E9

CE16HA D3cei6: ia D10CE16fIA D10CE16HA E10CE16HA E10

FC4M

4 pole 2 position AB Metal Productst y p e L O S W 4 2 1 E

Voltage Selector Switch Fcrtiphone TX1514

McMurdo Micronectnr P lug MP18 P1817

Texas Instruments 1S005 (preferred) RT54A atom Man. Co. 1N445 (alternative) RT54

6-way tag board Prestware6-way tag board PresKvare

550A059'550A059

E 6

C7

C5E7

H7

D9E9

E l lE3

) The capacity of each pair of capacitors) (C2/3 and C4/5) should be within r20%

cuiifiDE.»rai

1 " I iizi?i

h J

—

yr ~ ^ T ^ i * ! I

* O

P

* PC

S3

Oo

o

DCU 4

toCO

" \\/~r-r i *

/0^S\

TPS2

28

COKfiOENTIAl

CONDENSER RE-FORMER CIRCUIT

70

1 O , o'I?, o -di o »o 3

Tt° * °~K> i Or—

I iS<T. 1.

1A V S A

AAA/1—

S 3

* f t * * M .

b,l<i?MB

Rl

Connections between pin D3 on Plug and Socket to be as shownConnections between pin D-4- en Plug and Socket to be as shownConnections between pin A4 on Plug and Socket to be as shownConnections between pin B4 on Plug and Socket to be as shownPi". ?24 on Plug and Socket to be unconnectedAll other pins on Plug to be connected to corresponding pins on Socket

(to avoid confusion these connections are not shown)

SKT1P i?. 1R lR3R4

16 -way Micronector Socket McMurdo MS 1818-way Micronector Plug McMurdo MP 18Pesistor 4.7 Kohm + 10% Erie Type 8Rcs»stor 4.7 Kohm + 10% Erie Type 8Resistor 10 Kohm + 5% 3.5W Elcom Type 25420Posistor }0 Kohm - 5% 3.5W Elcom Type 25420

P1867P1817R81247KR81247KR58B/310JR58B/310J

:-NF !3tHTiA:

TP82

f.n?.7!nn:!in

71

29

29-1

29-2

29-3

MK. 123 RECEIVER TEST PF.OCEDVRE

Equipment Required

Signal generator covering tht following frequencies:-465 kc/s; 2*5 to 21-0 Mc/s.DC VVM 0-10V; l.P. impedance greater than 10M ohm.AC VVM 0-1V; 0-5V. I.P. impcd&ncc greater than 1 M ohm,

peak indicating*, calibrated R.M.S.AF Source, providing 10 mV; J00 mV; IV at 1 kc/s Output

imj>edaiH< lest thsis ICO? oh!ii>.High impedance or Amplivox phQMrb type E5A2K atrordjug

to t *&t COndl ' t iC j i . r .20,000 ohms resistor dummy load,

NOTE:- Test Point - T, P. 1. is the mixer valve grid (V.2)Circuit Ref. E. 6.

Test Point T.P.2. is the junction between R13 andC.26 Circuit Ref. D. 14.

A. F. Cain

Gain control set to minimum, AF source connected toTP.2. AC. V.V.M. connected across 20,000 ohm resistorwhich constitutes the only receiver output load.

Measured at 1 kc/s A.F. Input to TP.2.

I . P. O. P.

10 mV100 mV1 - 0 V .

0*15 - 0*3 V0-75 - 1-5 V1-15 - 1-75 V

- . - i .

I .F. Cain

Gain control maximum. B.F.O. off. Signal generatorset to 465 kc/s. CW and connected to T. P. I, directly via a0-01 yT capacitor. DC. V.V.M. connected to T.P.2.

Adjust I. F. transformer cores for maximum output.

mmmm

T P 8 2 7 2

29*3 The input required for 5V. D.C. Output at TP.2,Cont. ghould be within 50 - 100 uV. The local oscillator

remains operative.

29*4 I .F. Bandwidth

The overall bandwidth should be 5 kc/s. ± 200 c/sat - 3 dB.

2 9 - 5 B . F . O .

B.F.O. switched on. Set B.F.O. tuning control tomid position. RF signal applied as in section 29' 3. Adjustcore of L, 10 for zero beat.

The D.C. voltage obtained at TP.2. due to the B.F.O.should he from 1- 5V to 3- 5V.

The frequency range provided by the tuning controlshould be from ± 9 to i 11 kc/s.

29 '6 R.F. Sens i t i v i ty

Apply unmodulated RF signal to aerial terminals via200 ohm resistor. DC. WM connected to T.P.2. B.F.O.switched off.

Set band switch to 2*5 - 5*0 Mc/s range.

Align oscillator and RF cores at L. F. end and trimmers ^at H. F. end for maximum output on D. C. WM.

Note R. F. input required for 5V DC at T. P.2. and also theimage ratio at 2-5; 3*5 and 5*0 Mc/s.

Set band switch to 5- 0 - 10* 0 Mc/s range. Align at5-0 and 10*0 Mc/s.

Note the sensitivity and image ratios at 5*0; 7*0; 10*0 Mc/s.

Set band switch to 10*0 - 20*0 Mc/s range. Align theoscillator circuits at 10*0 Mc/s and 20*0 Mc/s. Track the

GPWIDmiJil

TP82fiCSflSFRTIAL

73

29*6Cont.

R.F. circuits at 11*0 and 180 Mc/s.

Note the sensitivity and image ratios at 10*0; 11*0; 14*0;180 and 20*0 Mc/s.

Th*; follo^'iti" P.. F. in^'ji* fsd to the aerial socket via200 ohms should give 5V DC at TP.2.

/ifR\

— ■* ■Band Frequency Sensit iv i ty* Image Ratio

Greater Thanz- 5 - 5 * 0 M c / s 2-5 Mc/s 3*0 - 6*0 jiV 50 dB

3-5 3-5 - 7-0 45

5-0 4-0 - 8-0 40

5- 0 - 10-0 Mc/s 5-0 Mc/s 6*0 - 12-0 nV 40 dB7-0 7*5 - 15*0 30

10-0 9*0 - 18-0 25

10 - 20*0 Mc/s 10-0 Mc/s 15-0 - 30-0 3011-0 15-0 - 300 30

14-0. 20*0 - 40*0 25

18-Q 20-0 - 40-0 2020-0 30-0 - 60-0 12

/f$^*N WIDEBTIW

CPKFiDUTIMT P 8 2 , . ;

3 0 M K . 1 2 3 T R A N S M I T T E R T E S T P R O C E D U R E

30* I Equipment Required

R.F. output power meter, range 0-30 watts, impedance500 ohms. Crystals of the following frequencies: 2*5 Mc/s;3*0 Mc/s; 5*0 Mc/s; 6*5 Mc/s; 10 Mc/s.Crystal socket adaptor.Crystal current meter.Milliamrneters to read 0*5 mA and 0* 150 mA.Morse Key.

30*2 Osc i l l a to r A l i gnmen t

Short out P. A. tuning condenser, C. 13.Switch to Band 1. Using crystal frequencies 2*5 Mc/s and5 Mc/s, adjust the core of L. 1 so that these frequencies canbe tuned through by means of the oscillator tuning condenser,i.e. the band edge frequencies should not coincide with eithermaximum or minimum setting of the condenser. Resonanceis indicated by maximum brilliance of the neon, LP. 1. and bymaximum reading on the meter inserted in series with the P. A.grid lead, i. e. in series with the Tag 3 lead.

Repeat the above for bands 2 and 3 using crystal frequencies5 Mc/s. and 10 Mc/s. for band 2, and 10 Mc/s. for band 3.

30*3 Aer ia l Tun ing Meter

Switch to Band 2 and insert 10 Mc/s. crystal* Removeshort circuit from P.A. condenser. Switch aerial tap to highimpedance position No.4. No aerial load. Tune oscillator forrespnance and P. A. for maximum reading on aerial tuningmeter, set C. 14 for full scale reading. (C. 14. is adjustedby a screwdriver on the 4 BA round head screw situated underthe morse key).

•30*4 Power Output

Insert 500 ohms, dummy aerial into the aerial socketon the contact cradle.

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30*4 Check the power output; crystal current and P. A. grid driveCont. current en the following frequencies:-

Band 1. 2*5: 3*0: 5*0 Mc/s. Xtal Fundamental* 2 . 5 * 0 : 6 * 5 : 1 0 * 0 " " »

arid 10* 0 Mr/s, using thz second harmonic of 5*0 Mc/s. Xtal.Band 3. 10*0 Mc/s. Xtal fundamental: 13*0 & 20*0 Mc/s

using the second harmonic of 6* 5 and 10*0 Mc/s.

Check that output is obtained on all position of the aerialtap switch.

1 T V A\ .,- Band Crys ta l Gr id PowerCurrent mA Drive mA O.P. Watts

l1 10 - 30 2*0 - 3*0 19 - 30 %

2 10 - 30 1*5 - 2*5 15 - 30 •

3 10 - 30 1*0 - 2-5 15 - 25

Tap 3 on the aerial switch gives the best match for500 ohm load at all test frequencies, except 20 Mc/s. whichmatches on Tap 2.

The aerial meter will give the following readings atfull output:-*

Greater than 290 ixA." » 3 0 0 u A ." " 3 0 0 ^ A .

Band 1.-»**«3 . " » •

Voltage & Current Measurements

The meter should be a 20,000 ohm. volt instrument.

The keyed condition is with the transmitter operatingat 10 Mc/3; fundamental Xtal frequency; Band-2; with 500 ohm.aerial load.

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30*5Cont.

H. T. Supply VoltageH. T. CurrentH.T. R ipp le (A .C.V.V.M. )

L.T. A.C. Vol tageL. T. Current (TX and RX)

VL. Anode VoltageVL. Screen Voltage

VI. Cathode VoltageVz. Anode VoltageVz. Screen VoltageBias to VI Grid o: Power SocketBias to V2 Grid fit Power Socket

76

K e y e d U n k e y e d

425 i 15V 480 ± 15V

120 ± 5 mA. Less than 5 mA.Less than 50V Less than 3*0V

6*1 i 0-15V 6*3 ± 0-3V

2.55 Amps310 ± 15V 465 + 15V300 ± 15V 465 ± 15V7*0 ± 1-5V425 ± 15V 480 ± 15V270 ± 15V 435 ± 15V

1-4 ± 0-2V 126 i 2V

13*0 ± 0-5V 126 ± 2V

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CONFIDENTIAL

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