JJJelectronics- RF Mixer with audio pre-amplifier

* Hi Performance RF Mixer (MC1496)* Pre-amplifier ,Audio stage * Voltage 11v-13.5v * voltage regulator* can be used as product detector, Beat frequency oscillator (BFO) and heart of direct conversion receiver the output frequency is the difference between the VFO frequency and the input frequency (for example input filter )

Tool required.Soldering iron (25w-40w), small cutter, trimming tool

Now let’s build the mixer

I would recommend fitting the parts in the order they appear in the part list.Resistor first, then semiconductors, coils and Capacitors.Make sure you put the electrolytic capacitors and diodes in the right way round .keep all components leads as short as possible.

When you have finished assembly of the board, check all the parts are in the right places.The soldering looks bright and good. Re-solder any suspect joints with a little fresh solder, check that there are no short or splashes of solder between tracks.

Resistors

R1 150R 1

R2, R6 1k 2

R3 100k 1

R4, R7 33k 2

R5, R14 2k2 2

R8 820R 1

R9, R10 390R 2

R11 8.2k 1

R12, R13, 2.7k 2

R15 1.2k 1

Picture is for illustration only; components may not be the same

Transistor, Diode and IC

D1 Zener 8.2v 1

D2 1N4004 1

IC1 MC1496 1

IC2 TL071 1

Capacitors

Note: You will find the some capacitors values on a paper with your order

C1, C5, C13, C14 100nf 4

C2 See note above 1

C3 1uf 1

C4, C6, C8 See note above 3

C7 47nf 1

C9, C10, C11, C12 See note above 4

C15 47uf 1

C3 and C15 are electrolytic capacitors and must be installed the correct way round. The Longest lead is normally positive; this lead should go to the hole marked“+“ on the circuit board.

Picture is for illustration only; components may not be the same

Miscellanies

Binocular ferrite core

You have to make 2 coilsWind 8 turns of the thin enameled yellow wire tightly onto the two holes balun core. Passing the wire through one hole and then back out of the other counts as one turn. Do this 8 times for eight turns. Both ends of the wire should project from the same side as shown.

Wind 2 turns of the enameled yellow wire as shown.

You have to remove the varnish from the enameled wire ends, you can use fine sandpaper or you can use hobby knife.Solder 8 turns to Pin 1 and 4 Solder 2 turns to pin 2 and 3

Testing2 methods to check this mixer 1: with my filter , audio amplifier and VFO *Connect a power supply to +12v and GND * Connect the filter , VFO and audio amplifier to the mixer*Tune the VFO to find a CW signal2 : You need an oscilloscope and 2 signal generators* connect the oscilloscope to the output of the mixerConnect 2 signal generator to the VFO-IN and FLT-IN and Put both signal generators to1MHz (you can choose any frequency)Adjust one signal generator so that the differences between them is about 5khz You can read the frequency and the shape from your oscilloscope * You can make a good receiver with this mixer, just connect VFO and connect filter, with suitable audio filter /audio power amplifier.