Cumbria Designs T
Contents
1. 4 5 Control Interface and switching One of the unique features of the T 1 is the provision on the main board of an interface to allow easy control of DC and signal switching This allows the user to easily configure the module to suit their application Each control input drives a 2N7000 FET These devices are optimised for 5V logic levels and will switch on at about 2V input The gates are held low with pull down resistors RN4 and RN5 so that with no control voltage applied a FET is fully off Taking the control input voltage above 2V turns the FET fully on activating that control The maximum recommended control voltage is no higher than the nominal 12V supply This allows the interface to be either driven by logic levels or switched supply voltage signals from relays etc The choice of control system will depend upon the users application but for the fastest transceive operation a processor based sequencer is recommended The audio control inputs deserve special mention Unlike the power or other signal switching controls these work in an inverse state With no control voltage the associated audio path is active with a high control voltage condition the path is disabled If the module is powered up without any control signals applied to the interface then all of the audio paths are active with the possibility of feedback between the loudspeaker and microphone if connected Should it be desired to use the T 1 module w2. placement and good soldering Don t be tempted to rush the construction even though this is a relatively simple kit a wrongly placed component can provide hours of frustrating fault finding Also as this kit uses a double sided Printed Circuit Board PCB with through plating removal of a wrongly soldered part can be difficult Follow the assembly instructions carefully to avoid mistakes 3 4 Component Identification All parts carry a coded identity to describe their values It is important to be able to recognise these during assembly Capacitors have their value printed numerically e g 104 100nF 103 10nF etc Resistors have their values represented by coloured bands this is a frequent source of confusion To simplify component identification the parts list carries the identities of each component as it appears on the device For resistors the colour coding is given This should be referred to during assembly to ensure the right parts are placed in their respective positions on the PCB 3 2 Component Leads Many of the passive components will require their leads to be formed to align with the holes on the PCB This mainly applies to the axial parts such as resistors and diodes Forming component leads is easily done with a pair of pointed nose pliers and using the hole spacing on the PCB as a measure Alternatively small formers T 1 PCB1 0 Version 1 4 made from scrap off cuts of Vero board etc m
3. pad to ensure a good connection Fit all three MMICs as described above If this is the first time you ve installed a Surface Mount Device congratulate yourself 5 2 IC Sockets Ensure correct orientation Match index cut out on socket to board printing Tip solder one pin only then check positioning before continuing Heat solder and reposition if necessary a Fit 8 Pin IC sockets in positions IC4 IC6 and IC7 b Fit 14 Pin IC Sockets in positions IC5 and IC8 5 3 Socket Strip Turned pin socket strip is used for mounting parts where a plug in installation is required Use a sharp scalpel or fine bladed modelling knife to cut the socket strip to length and fit as follows a Crystal Sockets X1 X2 and X3 Cut strip to three lengths of three sockets cut pin of centre socket and engage remaining two pins in crystal positions b VXO Inductors L1 and L2 Cut strips to two lengths of 5 sockets Cut off pins inside each strip leaving the end pins in place Mount each strip in the inductor position T 1 PCB1 0 Version 1 4 Page 9 of 20 2004 Cumbria Designs AGC Time Constant resistors R71 R73 and R77 Cut socket strip to two lengths of three sockets and mount each strip in resistor mounting holes in same axis as IC8 d Hi Lo Z Microphone Impedance Selector Cut a two socket length and solder in position next to microphone connector To select low impedance bridge the sockets by inserting a short wire link 5 4 Resistor N
4. transceiver for operation from 140 kHz to 400MHz The 1 main PCB carries all of the IF AF DC and signal T 1 PCB1 0 Version 1 4 switching stages of single conversion SSB CW transceiver from mixer to audio connectors A simplified block diagram of the T1 is shown in fig1 The design is broad band and features plug in filter modules and carrier crystals to allow easy configuration of IF and bandwidth options to suit the users application The main filter module accommodates two filters typically one for SSB and one for CW although if desired both filters could be configured for differing bandwidths of the same mode A tail end filtering scheme is implemented to clean up the wideband noise All signal routing and DC switching controls are extended to a 16 pin interface to provide the greatest flexibility in operation The controls can be operated by the users sequencing circuit or via the optional Cumbria Designs C 1 processor controlled sequencer module 4 2 Receive The RF input to the T1 is mixed to the IF frequency by M1 a TUF 3 diode ring mixer The output of the mixer is routed via PIN diodes through IC1 a high IIP3 MMIC amplifier configured as a bilateral stage Signal direction is set by the biasing of the PIN diode bridge The output of the post mixer amplifier is presented on FL to the plug in filter module The signal is routed on the filter module to the selected filter by steering diodes Impedance
5. R3 R4 R17 R20 R21 R24 R26 R31 R35 R43 R53 R67 3 150R R37 R49 R51 4 220R R6 R18 R25 R45 1 390R R8 8 560R R13 R14 R22 R23 R27 R28 R33 R39 11 1K R7 R9 R12 R19 R30 R34 R41 R42 R57 R63 R75 2 2K2 R48 R66 1 4K7 R68 15 10K R5 R50 R54 R55 R59 R60 R61 R62 R64 R65 R70 R71 R72 R76 R78 47K R40 R56 2 13 100K R10 R11 R15 R16 R32 R36 R38 R44 R46 R52 R69 R74 R79 1 220K R77 1 4M7 R73 1 10K 6X 1 103 RN6 1 10K 6X 2 103 RN4 2 10K 8 2 103 RN3 RN5 2 10K 10X 2 103 RN1 RN2 6 10K TRIMPOT VR1 VR2 VR3 VR5 VR6 VR7 1 100K TRIMPOT VR4 3 33PpF C6 C18 C19 3 120Pf C14 C23 C24 2 1500pF C49 C68 23 10nF CERAMIC C13 C15 C16 C17 C20 C21 C22 C26 C27 C28 C29 C30 C31 C34 C35 C42 C45 C51 C52 C53 C54 C57 C58 28 100nF CERAMIC C1 C2 C3 C4 C5 C7 C8 C9 C10 C11 C12 C25 C32 C33 C36 C39 C40 C41 C44 C47 C56 C59 C62 C63 C64 C69 C70 C73 1 0 47uF Poly C61 10 10uF ELEC C38 C43 C46 C48 C50 C55 C65 C67 C72 C74 4 100uF C37 C60 C66 C71 3 60pF TRIMMER TC1 TC2 TC3 3 FT34 43 CORES T2 T3 T4 4 47uH T1 L1 L2 L3 Design change T1 now axial inductor 1 1N4004 D1 1 1N4004 D20 Note on PCB 1 0 D20 is shown as D21 4 5082 3081 D2 D3 D8 D9 T 1 PCB1 0 Version 1 4 Page 19 of 20 2004 Cumbria Designs 14 BAV21 D4 D5 D6 D7 D10 D11 D12 D13 D14 D15 D16 D17 D18 D19 Note on PCB 1 0 D18 and D19 ar
6. protective plastic strips Do not unpack a MMIC until you are ready to solder it to the board e Resistors and diodes are generally supplied in bands Cut the component from the band when you are ready to fit it to the board e Loose pins are provided for the header connector shells During transit some of these may become lodged in the connectors Check and if necessary remove carefully T 1 PCB1 0 Version 1 4 e Choose a well lit work area with a light neutral covering e g white paper to help you spot dropped parts e Don t attempt to solder too many parts at once similarly limit your time spent soldering to a comfortable periods of say an hour taking breaks in between 2 2 Tools We recommend that the following tools are used during assembly and testing 25W fine tipped soldering 60 40 Rosin cored solder 5 or smaller diagonal side cutters Small pointed nosed pliers Solder sucker just in case Tweezers for SMDs Multimeter Oscilloscope 40MHz Magnifier 2 3 Conventions The following symbols are used within the assembly instructions to draw attention to critical steps such as component orientation and anti static precautions The associated narrative describes the action required Page 2 of 20 2004 Cumbria Designs nm Critical Step Static Sensitive 3 Assembly The production of successful finished working kit is dependent upon care during component handling
7. ALC is provided in the transmit IF path A power diode D1 is biased to a act as a variable resistor offering about 15dB of gain variation T 1 PCB1 0 Version 1 4 over a 12V control range The 50 Ohm output of the transmit IF is passed to the filter module where it is transformer matched to the filter impedance The filter removes the unwanted sideband determined by carrier oscillator frequency and the resulting SSB signal at IF frequency is transformer matched to the 50 Ohm IF port of the bilateral post mixer amplifier IC2 Signal direction through this stage is set by the biasing of PIN diodes D2 D3 D8 and D9 On transmit D2 and D9 are on whereas D3 and D8 are off In this condition the filter output is amplified by IC2 and passed to the mixer M1 The choice of local oscillator frequency and filtering on the RF port of M1 translate the SSB signal to the desired transmission frequency 4 4 Transmit CW Broadly the transmit operation in CW mode is similar to SSB but there are some important differences in the routing of the audio signal paths This is to provide sidetone during key down periods During CW operation the audio switches are configured such that the receive audio route is enabled and the input to the audio power amplifier IC7 is taken from the sidetone switch IC5A The transmit audio and AGC input switches are opened This configuration allows sidetone which is produced by M2 now acting as a pro
8. Cumbria Designs T 1 High Performance SSB CW Transceiver Sub System User Manual CONTENTS 1 INTRODUCTION 2 2 PREPARATION 2 3 ASSEMBLY 3 4 CIRCUIT DESCRIPTION 4 5 ASSEMBLY 8 6 TESTING 14 Appendix Component Overlay Appendix B Parts List Appendix C Circuit Diagram cumbria The Steading designs Stainton PENRITH Cumbria CA11 OES UK www cumbriadesigns co uk 1 Introduction Thank you for purchasing the Cumbria Designs T1 high performance SSB CW transceiver sub system We hope that you enjoy constructing this kit and find many uses for this feature rich design This manual describes the assembly and operation of the T1 even if you are a seasoned constructor we respectfully ask that you first read this manual and familiarise yourself with the instructions and kit contents before commencing construction If assembled carefully this unit will provide many years of reliable service The Cumbria Designs Team 2 Preparation 2 1 Unpacking The T 1 kit represents a reasonably complicated construction project which comprises over 270 parts some of which are very small and may easily be mislaid To reduce the risk of loss we suggest the following method of working e Keep all parts in a large clean container preferably a tin with a lid e When unpacking the anti static bags check very carefully to ensure that no parts are trapped in the corners of the bags e The MMIC amplifiers are packaged in
9. ake ideal templates that produce consistent results Some parts such as the variable resistors have preformed leads designed for machine assembly These will require straightening to align with the board layout Again a pair of pointed nose pliers should be used to carefully flatten the factory performing to produce straight leads 3 3 Soldering Before applying solder check carefully that the component you have placed is in the right position This is a through plated double sided board Whilst some of the pads are very small the area presented by the through plating is more than adequate to allow good solder flow to form mechanically strong good electrical joints These can be difficult to undo please double check The majority of problems are likely to be caused by soldering faults These can sometimes be difficult to find Here are some basic golden rules that will help you to avoid poor solder joints e Clean Iron Make sure your soldering iron tip is in good condition and tinned A small moistened pad for cleaning tips regularly used to wipe off excess solder and flux will ensure that your iron performs well Remember to tin the iron immediately after each wipe e Clean Leads and Pads All of the component leads and PCB pads in this kit are pre tinned and should not need cleaning before soldering Please ensure that parts are handled so as to avoid contamination with grease or fingerprints e Soldering Thi
10. ay from the wire end and tin with a hot iron Holding the iron on the exposed copper and applying solder will remove more enamel and tin the wire at the same time Inductor Primary Secondary Orientation T1 47uH Use axial inductor T2 15 turns 5 turns Secondary facing Q6 T3 16 turns 4 turns Secondary facing M2 T4 3 turn 20 turns Primary facing C29 Be sure to fit transformers with windings orientated correctly 5 17 A Axial Inductors The three remaining 47uH axial chokes Yellow Mauve Black Gold are installed as follows L3 Mount vertically next to M2 L1 and L2 Mount horizontally by trimming leads and plugging into socket strip 5 18 Connector Assemblies Connector shells and pins are supplied to allow connection of power audio and controls to the T 1 The use of good quality colour coded heat resistant multi stranded wire is recommended To avoid accidents a colour code convention should be chosen to represent function e g Red ve supply Black ground striped colours controls etc Each connector assembly comprise of two component parts the shell and the pins To terminate a conductor first strip back about 2mm of insulation and tin the exposed wire Place the tinned end of the wire into a pin such that the tinned wire sits inside the inner pair of tabs and the insulation sits within the outer tabs With small pointed nose pliers carefully compress the outer tabs onto the insulation to hold the wi
11. ctor Connect and antenna or signal source and adjust the carrier oscillator by listening to the unwanted sideband suppression level Change over sideband oscillators by grounding pin 12 and raising pin 14 Adjust USB carrier for good suppression and a similar passband sound to that of LSB operation Enable the AGC by grounding pin 1 of PL2 and set AGC gain by adjusting VR7 Note that too much gain may cause the AGC to overshoot indicated by a characteristic pumping of audio level A smooth AGC operation across a wide range of receive signal levels should be obtained PL2 Function Receive Transmit Transmit Pin SSB CW AGC system Signal Input Receive DC Control Microphone Audio path Transmit DC Control Filter A select Sidetone Audio path 1 2 3 4 5 Main Receive Audio path 6 7 8 Filter B select 9 AGC Speed 10 CW Carrier Keyed 11 Receive IF Mute 12 LSB Carrier 13 Spare Oo 14 USB Carrier Table 2 PL2 Control States Raising pin 11 of PL2 should mute the receiver Grounding pin 9 should switch the AGC to slow Note that without the Hang control provided by the T 1 Controller the slow AGC setting may be too slow for most purposes This can be changed by reducing the value of R73 to 1M 6 4 SSB Transmit Set Up Power off the T 1 and reconfigu
12. duct detector to be output from the loudspeaker With the transmit signal paths conditioned for CW on key down the CW carrier oscillator is powered producing a carrier signal The carrier signal is routed to the Tx IF path via buffer stage Q2 and diode switch D5 VR1 sets the drive level to the Tx IF this should be set for minimum unwanted in band products at the front end mixer output The CW carrier signal branches to both the Tx IF and to the M2 With one of the main carrier oscillators permanently running M2 Page 6 of 20 2004 Cumbria Designs demodulates the carrier to produce the audio sidetone signal that is then coupled to the audio stages as described above The other path via the Tx IF path amplifies the CW carrier and passes it to the filter module During CW transmit the narrow filter should be selected to ensure that intermodulation products generated by the action of the sidetone and carrier are removed The use of a narrow filter also provides further suppression of the main carrier oscillator The choice of main carrier oscillator to use in CW mode is up to the user The CW carrier frequency is adjusted to produce the frequency desired by the user 800Hz being typical As the transmitted CW carrier passes through the narrow filter on transmit if this is used on receive then a netted CW signal will fall within the receiver passband without the need to offset the main tuning
13. e shown as D19 and D20 7 2N3906 Q12 Q13 Q14 Q15 Q16 Q17 Q18 10 J310 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q10 Q11 13 2N7000 Q9 Q19 Q20 Q21 Q22 Q23 Q24 Q25 Q26 Q27 Q28 Q29 Q30 MAR2 SM IC1 ERA 4XSM IC2 MAR 3SM IC3 4066N ICS LM324N IC8 LM380N 8 IC7 NE5534N 4 IC6 Po N St TUF 3 MIXERS 1 2 Additional Parts Required for operation AF Gain 10K Log With switch for transceiver power on off IF Gain 10K Lin With optional switch for AGC on off Speaker 8 Ohm 2W Microphone Low or High Impedance strap impedance link to suit SMB Plugs For Local Oscillator RF connections Filters and Carrier Crystals T 1 PCB1 0 Version 1 4 Page 20 of 20 2004 Cumbria Designs
14. en from the DC port of the TUF 3 and forms a common bus between the receive and transmit audio circuitry T 1 PCB1 0 Version 1 4 Audio path selection is performed by a quad bi lateral switch IC5 The low noise pre amplifier IC6 raises the audio to a level to drive the audio power amplifier IC7 an LM380N 8 to provide up to 800mW of audio output The output of the pre amplifier is presented on PL1 the AF gain pot connector Additional connector pins allow access to the audio and provide 12v and ground for connection to an external DSP or other filter unit The AGC system is high performance full wave audio derived scheme This approach was chosen over RF derived AGC to offer repeatable and predictable performance Once adjusted it works very well indeed The AGC is switched on and off by the audio input switch IC3a An adjustable gain full wave audio rectifier is formed from two of the quad operational amplifiers IC8c and IC8b The demodulated audio is applied to IC8c a non inverting gain stage that drives one of the detector diodes and provides the input to IC8b a unity gain inverter that drives the second detector diode in anti phase Page 5 of 20 2004 Cumbria Designs The combined output from the two diodes is filtered by the AGC time constant circuit to produce the DC AGC voltage which is amplified by IC8a and applied to the level shifter IC8d VR7 sets the AGC gain and VR6 is adjusted set the quiesc
15. ent no signal AGC voltage The AGC system generates a decreasing AGC voltage for an increasing audio input The resulting AGC voltage is applied to the control FET s in the gain controlled AGC stages Manual IF Gain may be set by a 10K pot connected to the IF_GAIN connector 4 3 Transmit SSB The microphone input is matched and amplified by Q5 before being passed to IC4 a low noise amplifier which provides most of the gain The transmit audio level is adjusted with VR2 microphone impedance matching is set by the Hi Lo Z link open for medium high impedance closed for low impedance The transmit audio is routed via the transmit audio switch IC5D to double balanced mixer M2 During transmit this serves as the balanced modulator In SSB mode the audio switches are configured such that only the transmit audio path is enabled All other audio routes are disabled to prevent audio feedback and over driving of the AGC system The carrier oscillator input from the selected oscillator is modulated by the audio to produce a double sideband output from the modulator The receive IF amplifier is muted by turning on Q22 This holds the AGC line at ground setting the Rx IF gain to maximum attenuation preventing RF feedback from the Tx IF path The 50 Ohm output of the modulator is routed to the main crystal filter module by the transmit IF which comprises of switching diodes D5 and D4 and MMIC amplifier IC1 A facility to apply
16. etworks It is essential that each type is correctly identified and installed for the correct operation of the control circuitry Two types of resistor network are provided Commoned network identified by a 1 in the part number in the format No of pinsX 1 Value e g 6X 1 103 6 pins common 10K Pin 1 marked by a dot is the common the remaining 5 pins are the other ends of the commoned resistors Orientation of this type of network is critical Isolated network identified by a 2 in the part number in the format No of pinsX 2 Value e g 10X 2 103 10pins isolated 10K Orientation of this type of network is not critical although for aesthetic maintenance purposes you may wish to adopt a standard orientation a Fit 6 pin common network 6X 1 103 RN6 ensuring pin 1 is aligned to pin 1 on the PCB Note due to sourcing difficulties a 5 resistor package is supplied use the 10K resistor provided to connect the vacant end position to the common b Fit 10 pin isolated networks 10X 2 103 RN1 and RN2 C Fit 6 pin isolated network 6X 2 103 RN4 d Fit 8 pin isolated networks 8X 2 103 and RN5 5 5 Resistors Install all resistors mounting horizontal or vertical as required by PCB layout For horizontally mounted resistors bend leads sharply at end of body to 90 degrees and insert into board Solder and trim off excess leads Vertical 2 100R Brown Black Black Black Brown R17 R35 1 150R Brown Green Blac
17. ith a bespoke control circuit a convenient way of converting the 16 interface to 0 1 pitch linear presentation is to use a Cumbria PL2 Function High or Open Low Ground Pin 1 AGC system Signal Input AGC OFF AGC ON 2 Receive DC Control RX DC ON RX DC OFF 3 Microphone Audio path MIC Audio OFF MIC Audio ON 4 Transmit DC Control TX DC ON TX DC OFF 5 Main Receive Audio path Main RX Audio ON Main RX Audio OFF 6 Filter A select Filter A Selected Filter A de selected 7 Sidetone Audio path Sidetone Audio ON Sidetone Audio OFF 8 Filter B select Filter B Selected Filter B de selected 9 AGC Speed AGC Fast AGC Slow 10 CW Carrier CW Carrier ON CW Carrier OFF 11 Receive IF Mute IF Muted IF Normal Gain 12 LSB Carrier LSB Carrier ON LSB Carrier OFF 13 Spare Spare 14 USB Carrier USB Carrier ON USB Carrier OFF TS Ground to Sequencer Table 1 PL2 Functions 16 12V for sequencer T 1 1 0 Version 1 4 Page 7 of 20 2004 Cumbria Designs Designs LCDA kit This was originally to provide conversion from 8x2 to designed to simplify the connection of linear 16 way formats The function of LCD s to micro controllers but it is also each control interface pin is given in very well suited as a general adapter Table 1 5 Assembly The order of assembly is not particularly critical even though this is a relatively complicated circuit it is perhaps easiest to test it in its complete
18. k Black Brown R37 2 1K Brown Black Black Brown Brown R12 R57 4 10K Brown Black Black Red Brown R59 R60 R61 R62 2 100K Brown Black Black Orange Brown R11 R38 Horizontal 2 2R7 Red Mauve Black Silver Brown R47 R58 1 51R Green Brown Black Gold Brown R29 12 100R Brown Black Black Black Brown R1 R2 R3 R4 R20 R21 R24 R26 R31 R43 R53 R67 2 150R Brown Green Black Black Brown R49 R51 4 220R Red Red Black Black Brown R6 R18 R25 R45 1 390R Orange White Black Black Brown R8 8 560R Green Blue Black Black Brown R13 R14 R22 R23 R27 R28 R33 R39 9 1K Brown Black Black Brown Brown R7 R9 R19 R30 R34 R41 R42 R63 R75 2 2K2 Red Red Black Brown Brown R48 R66 1 4K7 Yellow Mauve Black Brown Brown R68 11 10K Brown Black Black Red Brown T 1 PCB1 0 Version 1 4 R5 R50 R54 R55 R64 R65 R70 Page 10 of 20 2004 Cumbria Designs R71 R72 R76 R78 2 47K Yellow Mauve Black Red Brown R40 R56 11 100K Brown Black Black Orange Brown R10 R15 R16 R32 R36 R44 R46 R52 R69 R74 R79 1 220K Red Red Black Orange Brown R77 1 4M7 Yellow Mauve Black Yellow Brown R73 Note R71 R73 and R77 plug into pin sockets to allow user optimisation 5 6 Diodes All diodes are polarity conscious The cathode is marked by a band on the diode body ensure orientation matches the PCB legend BAV21 Si
19. licon Signal Diodes Red glass bodies Install carrier oscillator steering diodes D6 and D7 Install IF signal steering diodes D4 D5 and D10 Install the six IF Bias diodes D11 D12 D13 D14 D15 and D16 Install AGC circuit diodes D17 D18 and D19 Note on V1 0 PCB the silkscreen component numbering skips D18 to show D18 and D19 as D19 and D20 and D20 Power Diode as D21 1N4004 Silicon Power Diodes Black plastic bodies a Install ALC attenuator diode D1 b Install Reverse polarity protection diode D20 D21 Note this mounts vertically with the cathode band towards the PCB 5082 3081 PIN Diodes Clear or black glass bodies Install the four post mixer amplifier signal steering diodes D2 D3 D8 and D9 5 7 Ceramic Capacitors Insert leads into PCB such that the capacitor body is flush with the board surface Bend the leads outwards slightly to hold the capacitor in place during soldering Trim off excess leads 33pF 33J C6 C18 C19 120pF 121K C14 C23 C24 1500pF 152 C49 C68 3 10nF 103 C13 C15 C16 C17 C20 C21 C22 C26 C27 C28 C29 C30 C31 C34 C35 C42 C45 C51 C52 C53 C54 C57 C58 28 100nF 104 C2 C4 C5 C7 C8 C9 C10 C11 C12 C25 C32 C36 C39 C40 C41 C44 C47 C56 C59 C62 C63 C64 C69 C70 C73 5 8 Transistors Polarity conscious components Make sure that orientation is correct The J310 and 2N7000 are Static sensitive parts Inse
20. matching 50Ohms to the filter input impedance is performed by toroidal transformers Each filter can have up to 6 poles crystals and parts placement allows for several different filter configurations to be realised For good performance and repeatability we recommend that the minimum loss Cohn design is used Page 4 of 20 2004 Cumbria Designs TUF 3 Mixer Post Cascode IF Amplifier Control Interface Fig 1 T 1 block diagram Tail En Filter TUF 3 Carrier Buffer Amplifer Carrier Oscillators The filter kit supplied with the T1 and its instructions has been produced on this basis The output from the crystal filter module is presented via FL1 to the gain controlled IF stages comprising of a two stage JFET cascode amplifier This provides a gain of about 50dB and an AGC range in excess of 90dB The diode chain D11 D16 lifts the source voltages of the IF stage increasing the AGC range The output from the IF stage is filtered by a two pole crystal filter to remove wideband noise before being amplified by Q8 which provides a fixed gain of about 15dB and matching into the TUF 3 product detector M2 The IF signal is demodulated to audio by mixing in the product detector with the selected carrier oscillator Two JFET Colpitts oscillators are used to generate LSB and USB carriers which are amplified by IC2 a MMIC Amplifier to around 7dBm to drive the diode ring mixer The audio output is tak
21. o compensate for the small size of these parts large pads have been provided on the PCB to ease soldering A magnifier is essential to identify part type and orientation Before opening the MMIC packaging you are advised to cover the work area with a large sheet of white paper so that should you drop a device you will be able to find it easily The three MMICs are identified as follows Device Function Device Marking MAR 2SM IC1 Tx IF Amplifier 02 MAR 3SM IC3 Carrier Amplifier 03 ERA 4XSM IC2 Post Mixer Amplifier 4 T 1 PCB1 0 Version 1 4 Page 8 of 20 2004 Cumbria Designs MMIC Package PCB Layout Arrowhead marks signal flow LM silkscreen pad Fig 2 MMIC physical appearance and corresponding PCB layout Soldering MMICs With a little care and concentration the MMIC devices are relatively easy to install a Lightly tin each MMIC PCB pad removing excess with a solder sucker or solder wick b Place the device onto it s mounting pads aligning it so that the leads fall centrally inside the respective pads Check orientation c Hold the MMIC gently in place with the end of a fine pointed tool such as the blade of a modelling knife and secure one pin by melting pad tinning with a lightly tinned soldering iron d With the MMIC secured by one pin check alignment adjusting if necessary by apply gentle sideways pressure e Lightly solder each of the unsoldered pads and finally re solder the first
22. onitored on a loosely coupled receiver with a narrow filter or better still a spectrum analyser if you have one to confirm the signal is clean Re adjust the sidetone level if necessary 6 6 Need Help Hit a problem that you can t resolve Don t worry we re here to help Contact us by letter or email at supporto cumbriadesigns co uk for support T 1 PCB1 0 Version 1 4 Page 16 of 20 2004 Cumbria Designs The Assembled T 1 with Filter Kit Typical T 1 Application Rx Switch Pre select RF Cumbria Designs T 1 LO PA Strip AF Gain IF Gain Local Controller Oscillator F Rx Freq IF Controls Key PTT Frequency 7dBm to 10dBm T 1 PCB1 0 Version 1 4 Page 17 of 20 2004 Cumbria Designs T 1 Component Overlay Appendix A zew amn 93 sub1soperaquna ann Sleep sme D ard Nive dl xum E x n ae Em nid Tu Bs Fu Ed uod 4 oaz 319 oy cathe ae eet gd Version 1 4 Page 18 of 20 2004 Cumbria Designs T 1 PCB1 0 Appendix T 1 PCB VERSION 1 0 PARTS LIST 2 SMB LO RF 1 ML16 PL2 5 HEADER 2 WAY ALC LS MIC PWR S METER 5 SHELL 2 WAY 1 HEADER 3 WAY IF_GAIN 1 SHELL 3 WAY 1 HEADER 6 WAY PL1 1 SHELL 6 WAY 20 CONNECTOR PINS 1 PIN SOCKET 16 WAY ENAMELED COPPER WIRE T 1 PCB 2 2987 R47 R58 1 51R R29 14 100R R1 R2
23. or solder bridges or misplaced parts 6 2 Power Up With no control signals applied to PL2 all of the audio paths are active This means that if a microphone and speaker are connected howl round will occur The control states for typical LSB operation are shown in table 2 below These may be adapted and used to control the T 1 in a simple Tx Rx switching scheme For fast break in operation the controls will require to be sequenced to reduce audio disturbances during transitions The settings assume the following configuration LSB Operation Dual Filters fitted A and B Filter A SSB Filter B CW Fast AGC enabled With the controls shown the T 1 will draw about 200mA from a 12V supply 1 supply fuse is recommended to protect the T 1 This will blow on reverse polarity or if a major short circuit occurs T 1 PCB1 0 Version 1 4 Page 14 of 20 2004 Cumbria Designs 6 3 Receive Set Up With 12V applied check that the current is in the region of 200mA Disable the AGC input by taking pin 1 of PL2 high and advance the AF gain until a faint hiss is heard With no IF Gain pot attached adjust the AGC bias pot VR6 for maximum IF noise this will be at an AGC voltage of about 8V If no noise is heard check that the carrier oscillator is functioning and that the right DC conditions have been applied to the control connector PL2 Connect a 7dBm local oscillator source set to the desired receive frequency IF frequency to the LO SMB conne
24. re Repeat this with the inner tabs to grip the exposed conductor Very carefully solder the exposed conductor in place taking care not to allow solder to flow onto the locking tab Finally insert the pin into the shell with the small locking tab orientated to the face of the shell with the small cut outs Push home until the locking tab snaps into the cut out Should you need to remove a pin gently press the locking tab in with a small screwdriver or the end of some pointed nose pliers The pin will be released and can be pulled out of the shell T 1 PCB1 0 Version 1 4 Page 13 of 20 2004 Cumbria Designs PWR Locking LS Tab T Gnd Out Gnd 12V AF Gain Pot IF Gain Pot Rear Front S Meter MIC In Gnd Control Voltage 0 lt V lt 25v Fig 3 Connector Wiring Assembly complete well done Now carefully check your work for dry joints and bridges before moving on to testing 6 TESTING The testing sequence assumes that the filters and carrier crystals have been have been installed 6 1 DC Tests Before connecting the T 1 to your power supply for the first time carry out these simple checks just to be safe Using a multi meter check for short circuits on the DC input and each of the switched supply rails downstream of the 2N3906 DC switching transistors Depending upon the specification of you meter resistances in the order of 100 Ohms upwards should be seen If you find less than this check the tracks f
25. re the control inputs for transmit SSB operation Connect a microphone setting the Hi Lo Z impedance link to suit Power on the T 1 with a receiver loosely coupled to the RF port of the T 1 it should now be possible to monitor the SSB output The microphone gain is set by VR2 An oscilloscope of suitable bandwidth connected to the RF port should show a peak to peak output of approximately 150mV 6 5 CW Transmit Set Up During CW it is recommended that a narrow filter is selected to reduce further low level bleed through of the sidetone signal If the T 1 filter dual unit is used set the controls to select Filter B during transmit or during both transmit and receive The CW filter on the T 1 filter board will favour operation with the USB carrier oscillator T 1 PCB1 0 Version 1 4 Page 15 of 20 2004 Cumbria Designs In transmit with the narrow filter and USB selected raise the CW Carrier control pin 10 This turns on the CW carrier oscillator An audio sidetone signal will be heard from the loudspeaker The sidetone level is adjusted by VR3 With the RF port connected to an oscilloscope adjust the carrier level VR1 until no increase in amplitude is seen At this level the output will contain low level intermodulation products especially if you are using the SSB filter in CW mode back off the carrier level VR1 until the amplitude just starts to fall Any distortion products will now be reduced to an acceptable level The RF output can be m
26. rt transistors so as to leave about 3mm of lead between the body and the board Solder centre lead check position and solder outside leads trim off excess leads 7 2N3906 PNP Q12 Q13 Q14 Q15 Q16 Q17 Q18 10 J310 J FETs Q1 Q2 Q4 Q5 Q6 Q7 Q8 Q10 Q11 13 2N7000 Power FETs 09 Q19 Q20 Q21 Q22 Q23 Q24 Q25 Q26 T 1 PCB1 0 Version 1 4 Page 11 of 20 2004 Cumbria Designs Q27 Q28 Q29 5 9 Variable Resistors The pre formed leads will require to be straightened to fit 6 10K 103 VR1 VR2 VR3 VR5 VR6 VR7 1 100K 503 VR4 5 10 Variable Capacitors 3 60pF Yellow body TC1 TC2 TC3 5 11 Electrolytic Capacitors Polarity conscious Capacitors the short lead marked goes to ground 10 10uF C38 C43 C46 C48 C50 C55 C65 C67 C72 C74 4 100uF C37 C60 C66 C71 5 12 Polystyrene Capacitor 1 0 47uF C61 5 13 Connectors a Headers Recommended Header Connector orientation is as marked on the PCB with rear locking tab facing into the centre of the board 5 2 way headers ALC HI LO Z LS MIC PWR S METER 1 3 way header IF GAIN 1 6 way header PL1 1 8x2 header PL2 b Pin Strip Plug in filter connections are made by pin and socket strip It is recommended that the pin strip part is fitted to the main PCB and the socket part in filter kit is fitted to the filter boards Cut lengths of strip to suit the broad end of the pin strip is inserted into the main PCB Solder one pin check connector
27. s is the bit that can trip up even experienced constructors For the Page 3 of 20 2004 Cumbria Designs solder to fuse with the surfaces to be joined it is necessary for them to be hot but not so hot as to damage the parts It s a simple as 1 2 3 1 Place the tip of the iron against the joint hold it there briefly to bring the metal surfaces up to temperature 2 Apply the solder allowing it to flow smoothly onto the surfaces 3 Hemove the iron and inspect the new joint The finished joint should have a smooth shiny coating of solder If the joint is dull grey or has formed a spherical blob apply the iron to the joint remove the old solder with a solder sucker and re solder Mistakes They do happen Should inadvertently solder a part in the wrong position we recommend that you DO NOT attempt to remove it intact To prevent damage to the plated through hole PCB through excessive over heating and mechanical strain the wrongly placed part should be cut off the board leaving it s leads pins exposed These can then be removed carefully one by one and the PCB pads de soldered and prepared for the replacement If you have difficulty in sourcing a replacement part contact us We hold high volumes of parts for our kits and can offer components at competitive rates 4 Circuit Description 4 4 General The Cumbria Designs T1 is a high performance sub system designed to serve as the core of an SSB CW
28. sits correctly adjusting if necessary solder remaining pin s 1 2 way pin strip FL1 2 4 way pin strip FL2 and FL3 5 14 DIL Integrated circuits Static sensitive parts Discharge yourself to ground before handling Avoid wearing static generating clothing e g wool man made fibres etc during assembly Orientation is critical Observe correct alignment of IC pins which will need to be gently formed for correct alignment before insertion into sockets IC pins can be pushed inwards by placing the device on its side on a firm surface and gently pressing the body down against the pins When inserting parts take care to check pin alignment 2 NE5534N IC4 IC6 1 4066N IC5 1 LM380N 8 IC7 1 LM324N IC8 T 1 PCB1 0 Version 1 4 Page 12 of 20 2004 Cumbria Designs 5 15 Packaged Mixers Static sensitive parts Discharge yourself to ground before handling Avoid wearing static generating clothing e g wool man made fibres etc during assembly Fit TUF 3 Mixers in positions M1 and M2 taking care to observe marked orientation The pin clearance may be tight if this is the case gently work the device into position 5 16 Transformers Almost there To provide increased gain at lower IF operating frequencies T1 has been replaced by an axial 47uH choke Yellow Mauve Black Gold Wind the three IF inductors T2 T4 onto FT34 43 cores as described in the table below Trim the ends to fit the board Before insertion scrape the enamel aw
29. state rather than to attempt to carry our individual stage testing as construction progresses The key to success is simply to ensure that the right component is placed in each position As this is a plated through hole board removal of a misplaced part is best done by cutting the part off the board and then carefully removing each residual lead pin from the PCB This results in the destruction of the part but overheating and possible damage to the PCB pads is avoided Please check very carefully the value and orientation of each part before soldering In the words of the carpenter Measure twice cut once The following recommended assembly sequence is based upon part profile and will allow parts to be held in place whilst the board turned over whilst soldering Unless stated otherwise all components are mounted on the top silk screen side of the board You are strongly advised to check off each part number as it is installed to keep a track of progress PRECAUTIONS Static sensitive components Discharge yourself to ground before handling Avoid wearing static generating clothing e g wool man made fibres etc during assembly Critical step during installation such as orientation Read associated note 5 1 Monolithic Microwave Integrated Circuits MMICs Three very small surface mount MMIC amplifiers are employed in the circuit These devices provide excellent performance with a significant saving in components and complexity T
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