EA3GCY My First Transceiver MFT-40 Assembly Manual Download

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MFT-40 DSB Transceiver Kit

Page 1

MFT-40

irst

ransceiver

40 Meters DSB Transceiver Kit

Assembly manual

Last update: June 1, 201

[email protected]

Most recent updates and news at

www.ea3gcy.com

Thanks for constructing the

MFT-40 DSB Transceiver kit

Have fun assembling it and enjoy QRP! 73 Javier Solans, ea3gcy

Summary of Contents for My First Transceiver MFT-40

Page 1: ...eiver 40 Meters DSB Transceiver Kit Assembly manual Last update June 1 2017 ea3gcy gmail com Most recent updates and news at www ea3gcy com Thanks for constructing the MFT 40 DSB Transceiver kit Have...

Page 2: ...es a DC direct conversion receiver with a 3 stage front end passband filter followed by a balanced mixer an audio preamplifier and filter using an operational amplifier and an output amplifier for dri...

Page 3: ...INNING TIPS FOR FIRST TIME BUILDERS Tools required A 30w soldering iron with fine tip small wire cutters for cutting component leads wire strippers long nose pliers needle nose pliers X Acto knife scr...

Page 4: ...There is a similar notch on one end of the IC socket that should be oriented over the U printed on the circuit board Finally pin 1 of the IC is also marked with a small dimple or dot this end of the I...

Page 5: ...yellow 2 10K P3 P4 Trimmer 10K 103 103 trimmer 1 1K P1 RX Gain Potentiometer B 1K lin 1 50K P2 Tune Potentiometer B 50K lin Capacitor list Qty Value Checked Ref Identified 2 470n C39 C40 474 or 0 47...

Page 6: ...2 T37 2 L10 L11 LPF toroids 9 5 mm diam Red L4 Toroid Tuning inductor NO USED 4 5u3H 3334 L1 L2 L3 L6 shielded coils 5u3H 5u3H 2 FT37 43 L7 toroid 10t 3t L9 toroid 8t 8t 9 5 mm diam Black 1 7 200 X1 7...

Page 7: ...erator E 2 R16 56K green blue orange DSB Generator D 2 R17 56K green blue orange DSB Generator D 4 R18 10K brown black orange Electret mic Bias F 1 R19 4K7 yellow violet red Electret mic Bias F 3 R20...

Page 8: ...22P 22pK or 22J VFO out J K 5 C35 1n 102 or 0 001 VFO J 4 C36 22p 22P 22pK or 22J VFO out I 4 C37 100n 104 or 0 1 VFO L 6 C38 100n 104 or 0 1 VFO K 4 C39 470n 474 or 470K Mic Input D 1 C40 470n 474 o...

Page 9: ...L08 MC78L08 TX Bias supply D E 10 Inductors RF Transformers Relay Checked Ref Value Type Ident Comment Circuit section Located L1 KANK3334 5u3H K3334 or 5u3H Rx Mix K 10 L2 KANK3334 5u3H K3334 or 5u3H...

Page 10: ...MFT 40 DSB Transceiver Kit Page 10 143 QUADRANT COMPONENT LAYOUT MAP...

Page 11: ...Refer to the parts list and select the first resistor R1 Bend the leads as close to the component body as possible and place them into the appropriate holes according to the component outline printed...

Page 12: ...their respective locations as identified on the circuit board in the same manner as you did with the resistors but leave a separation of 1 1 5mm from the board Diodes Next mount the diodes being caref...

Page 13: ...Refer to the identified column in the parts list Install and solder all the capacitors C1 to C67 When you mount them make sure to leave the leads as short as possible C63 C64 and C65 are polystyrene...

Page 14: ...ve their type printed on the component body Place them according to the corresponding component outline printed on the circuit board Transistors Q1and Q2 of the type BC547 Q3 is a PN2222 Q4 is a BD135...

Page 15: ...wards the notch in the IC socket or the U on the component outline Mount the sockets for IC1 IC2 IC3 and IC6 in the locations printed on the circuit board Make sure that the sockets lie flat against t...

Page 16: ...n LPF Toroids L10 and L11 L10 and L11 are identical They use T37 2 cores red toroid with 9 5mm 0 375in OD Cut 25cm 10 of 0 5mm diameter enameled wire and wind sixteen 16 turns on a red toroidal T37 2...

Page 17: ...Leave pigtails of 10 20mm 0 70 Now take about 8cm 3 5 of 0 5mm diameter enameled wire and wind three 3 turns on the other side of the toroid spacing the turns within the space between the turns of th...

Page 18: ...o the direction of the winding Toroidal transformer L9 L9 is an impedance matching transformer with a bifilar winding An FT37 43 is used black toroid with 9 5mm 0 375in OD It has 8 8 turns Cut a 31 32...

Page 19: ...and separate the two windings Use a sharp X Acto knife to scrape the enamel off the ends that will be soldered The ends of the coils that we have made need to be prepared in this manner before solderi...

Page 20: ...t 50 60KHz of the band To comfortably tune I recommend using a control knob at least 20 30mm diameter RX Gain Potentiometer P1 Volume Install the RX Gain potentiometer P1 as shown in the picture You m...

Page 21: ...st the mic gain P4 to maximum Push to talk put the transceiver in transmit mode PTT to GND Speak loudly or whistle in front of the microphone and adjust L6 to achieve maximum output power Adjustment o...

Page 22: ...overage segment can be modified Placing a capacitor in C27 will add to DV varicap diode capacity and the frequency will go down Try small values such as 10p 22p The C29 and C30 values also significant...

Page 23: ...y by the audio amplifiers To minimize or eliminate these interference try the following Use a single band antenna instead of multi band or broadband antennas Keep the RX GAIN knob to minimum use headp...

Page 24: ...nce is needed you are welcome to send an email to ea3gcy gmail com As a last resource you may send the kit in for repair however I will have to charge for any repairs done although I will try to keep...

Page 25: ...ion and used correctly according to all provided instructions It is your responsibility to follow all the instructions in the manual to identify all the components correctly and to use good workmanshi...

Page 26: ...MFT 40 DSB Transceiver Kit Page 26 SCHEMATIC...

Page 27: ...TX RX full use RX TX Transceiver use normal use Note that if you use the RX along with the TX you do not have to connect anything in VFO TX V VRX VTX and RX ANT terminals The VFO TX and VTX terminals...

Page 28: ...MFT 40 DSB Transceiver Kit Page 28 WIRING To use RX only...

Page 29: ...ng screen tape The MFT 40 is not protected against reverse polarity It is a good idea is to place a diode i e BY255 or larger in parallel with the power supply input The cathode the end of the diode w...

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EA3GCY My First Transceiver MFT-40, Assembly Manual

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