Re: ZN414 and TA7642 radios
Here is the circuit diagram of the radio I made. For the audio stage I used an LM386N based amplifier from eBay. The radio section works fine from around 0.9 V to 1.5 V but as expected the amplifier needs around 9 V.
From my experience I found that the radio had the best gain when assembled on copper stripboard rather than perforated board. Also keeping the MW coil to one end of the ferrite rod rather than the centre gave me the maximum number of stations without any duplicates. Something to bear in mind is that often radio programs are simulcast on different frequencies, so they are not necessarily unwanted image frequencies of the same station.
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