Components List Of Double Conversion FM Superhet Receiver
RF Amplifier
Resistors. All carbon 1/4 Watt
R1 150K. R2 27K. R3 270R. R4 270R.
Capacitors
C1 1nf. C2 1nf. C3 1nf. C4 1nf. All disc ceramic. CX coupling capacitor for connecting to VHF mixer- 10PF. NB May call for experimentation for best results. Alternatively a 30PF trimmer may be a best bet.
Trimmers
TC1 15PF. TC2 15PF.
Inductors
L1/L2 7 turns of 16 SWG enamelled copper wire about 7 to 10mm diameter air spaced.
Transistors
TR1 40673 dual gate FET.
VHF First mixer and local oscillator
Resistors. All carbon 1/4 Watt
R5 100K. R6 2K2. R7 100K. R8 470R. R9 2K2. R10 4K7.
Capacitors. All ceramic disc except where stated.
C5 33PF. C6 10nf. C7 6PF. C8 100nf. C9 100uf electrolytic capacitor 16 Volt minimum working voltage. C10 100nf. C11 100uf electrolytic capacitor 16 volt minimum working voltage.
Variable Capacitors and trimmers
VC1 15 to 30PF air spaced preferably Jackson Brothers type.
TC3/TC4 15PF. TC5 30PF.
Transistors
TR2 40673 dual gate FET. TR3 BF244B or 2N3819 FET. NB If using 2N3819 for TR3, R10 needs to be reduced to 1K.
Inductors
L3/4 7 turns of 16 SWG enamelled copper wire about 7 to 10 millimetre diameter air spaced
IFT 1 and IFT 2
10.7MHZ Toko type or just 1 10.7 MHZ valve type. The type I am using is the Toko TKAC-S34342BM available from the following web address BEC Distribution Limited providing they have stock or try JAB Electronics Toko 10K Coils You may need at least 5 of these, if you decide to build the additional 10.7 MHZ IF amplifier.
Second HF mixer and oscillator
Resistors. All carbon 1/4 Watt
R11 100K. R12 2K2. R13 100K. R14 4K7. R15 220R. R16 2K2. R17 1K.
Capacitors. All disc ceramic except where stated.
C12 100PF. C13 10nf. C14 1000PF. C15 100nf. C16 100uf electrolytic 16 volt minimum working voltage. C17 100nf. C18 100uf electrolytic 16 volt minimum working voltage.
Trimmers
TC6 30PF
Inductors
L5 10.7 MHZ IF transformer for oscillator coil. Only single tuned winding is used and may be the same type used for IFT 1/2.
Transistors
TR4 40673 dual gate FET. TR5 BF244B or 2N3819 FET.
IF Amplifier
Resistors. All carbon 1/4 Watt.
R18 2K2. R19 680K. R20 390R. R21 1K5. R22 2M2. R23 220R. R24 4K7.
Capacitors. All disc ceramic except where stated.
C19 1000PF. C20 0.02uf. C21 0.02uf. C22 100uf electrolytic 16 volt minimum working voltage. C23 100nf. C24 100uf electrolytic 16 volt minimum working voltage. C25 100nf. C26 0.01uf.
Transistors
TR6 and TR7 BC547
FM Demodulator
Resistors. All carbon 1/4 Watt
R25 220K. R26 470R. R27 10K. R28 1K.
Capacitors. All disc ceramic except where stated.
C27 200PF. C28 0.01uf. C29 0.47uf NB If you intend using a valve audio amplifier, I recommend You use a polypropylene type of about 500 volts or more for safety and don't connect to the AC/DC type that incorporates a live chassis. C30 100nf. C31 1000uf electrolytic 16 volt minimum working voltage.
Transistors
TR8 and TR9 2N2369A.
Diodes
D1 and D2 IN4149 silicon.
Audio Amplifier
Capacitors. All disc ceramic except where stated.
C32 100nf. C33 220uf electrolytic 16 volt minimum working voltage.
Integrated Circuits
IC1 TDA7052
8 pin IC socket
Potentiometer. 4K7 Log with switch for S1. Choice is up to you.
Miscellaneous
Plain matrix board or PCB for mounting components. NB Do not attempt to use copper clad stripboard, especially in the VHF or HF RF circuits as there is a high risk of stray capacitance leading to poor performance and instability.
Vereo pins for interconnecting wires and coils on circuit board.
Tinned copper wire for interconnecting wires on circuit board
Solder. Multicore type and 25 Watt soldering iron.
Antistatic mat and whist strap for handling the field effect transistors NB This precaution is not required when designing valve projects and must be only used on a temporary basis while constructing this design as there is a risk of fatal electrocution to earth due to the higher voltage used in valve circuits.
Test equipment
RF signal generator. Must have a frequency range of no less then 120 MHZ For aligning the VHF circuits and IF stage.
General propose multimetre for fault finding.
Power Supply
6 AA size zinc carbon type batteries, recommended when first testing this design or a power supply with a current limiter. 6 AA size Duracell type, recommended for regular portable use. Do not use a power supply higher then 10 volts on this design as there is a high risk of burning out the transistors and IC1. I will sometime recommend a low voltage regulated mains power supply for this design in the later future for continues home use
Component Suppliers
Cricklewood Electronics CCTV and Electronic Components Recommended for all the semiconductors for this design and now has a secure ordering page when making online transactions.
Jackson Brothers - Variable Capacitors and Drives
Please refer to the link How To Get Components with links to other component suppliers.
Back to-Double Conversion Pulse Counting FM Superhet Receiver With 10.7 MHZ First IF Stage