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Radio Shack Special - R adio Shack Special.a one transistor...

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Radio Shack Special ...a one transistor super-regenerative FM receiver Here is what one hobbiest  had to say about his maiden voyage with the Radio Shack  Special! T his radio is sensitive enough to tune 20 stations across the FM band, some with  volume high enough to drive a small PM speaker The ability to tune 88.9 MHz and  89.1 MHz is testimony of its selectivity. The signal-to noise ratio rivals that of the  better walkman type radios".  Phillip Crane   mailto:[email protected] Just click on the above picture for an in-depth view of each component ~ In the beginning ~ I have browsed the world wide web many a months back in 2002 in search of a one transistor FM receiver. I have seen a few... but they were always attached to some sort of added device., such as another IC or another transistor for doctoring up the receiver itself. Through my continued quest of searching for that 'too good to be true' one transistor unit, I happened to run across a particular schematic of a VHF super regenerative receiver by Charles Kitchen, famous for his vast knowledge of
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regenerative designs. I printed the schematic and made it. It turned out extremely well...for a two transistor, three coil unit. What made this circuitry more involved were the 13 capacitors, 4 resistors and two potentiometers. This brought the total component count to 24 in the receiver...not even mentioning the audio portion. With the RSS 'receiver section' being only 12  components, this little jewel can be made in a short period of time. With its'  marvalous sensitivity/selectivity/ and great audio sound...this simple  circuitry is surely giving its' all. With much experimentation and 'un-design'...as I call it, I began taking away a single component of the 'newly-made' receiver...one by one a component came off. Down to one transistor and two coils and 8 other components...it finally stopped. I then put component number 12 back. I must say that without sacrificing or comprimising it's superb sensitivity and selectivity in the original 24 component design, this 12 component count is still shining it's light as bright as it can; not forgetting to maintain the same crisp and clear original audio.
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Close by it's side is the LM386 audio amplifying circuitry. The component count in this audio area rivals that of the receiver itself! With only 8 devices, the sound quality coming from the headphones is 'quality at it's best'! Even though I took off another component in the audio section, the unit still did not deter from it's original sound quality! The SOURCE and DRAIN Coils... I then continued to experiment and re-design it's large RFC. Now...standing no taller than 1/2 inch and 8mm's in diameter, this  homemade choke, in which I call the SOURCE Coil, is doing its' job just  fine .
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Close by it's side is the DRAIN Coil, with a 2 turn tap. My latest design is made with a 3 turn tap...which makes the unit even more sensitive to stations being received. With
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