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The 'bulk' capacitors (supply rail decoupling capacitors) have virtually zero effect on reception sensitivity but they do have some effect on the audio quality and stability. For example, the LM386 draws very little current when quiet but the current increases with volume level. That in turn causes a slight drop in the supply voltage which can then decrease the volume. Under worst circumstances, you get a feedback effect where the amplifier makes a noise like a bad 2-stroke engine, the capacitors help by keeping the voltage up during peaks of current demand so lessening the effect. The value (their storage ability) is what matters but in this application the exact type you use is unimportant as long as it has >12V rating.
The VFO is basically an amplifier and a tuned feedback circuit. In this case you DO want it to oscillate. The feedback path is between pins 1 and 2 but the amplifier is all inside the MC3361 so it will not work if it is removed I'm afraid.
Brian.
The VFO is basically an amplifier and a tuned feedback circuit. In this case you DO want it to oscillate. The feedback path is between pins 1 and 2 but the amplifier is all inside the MC3361 so it will not work if it is removed I'm afraid.
Brian.