Easy-to-make shortwave super-regenerative receiver circuit diagram

Super regenerative receivers have high sensitivity, but the question is whether they are suitable for shortwave reception. Super regenerative receivers are also relatively easy to make. Start by making an RF oscillator that works at the frequency you want to receive. The difference between a super regenerative receiver and an oscillator is only in the base circuit. as the picture shows. A voltage divider is not used here but a high value resistor is used. When the amplitude of oscillation is sufficient to produce a strong negative charge that is repeatedly added to the base. This causes super regenerative oscillation. If the reproduction band is audible. Then adjust the resistor and capacitor values ​​until it reaches just above 20kHz. Adjust until you hear a rustling sound. Subsequent audio amplifiers should have a lower high-end cutoff frequency, which can greatly attenuate the regenerated signal at the output end. Pass the useful signal through the audio frequency band.

2 transistors are used in the circuit. 2 32Q headphones. The component values ​​shown are suitable for receiving signals in the 10-20MHz frequency band. The coil uses AA batteries as the skeleton and is wound with 27 turns of wire. The circuit will produce a strong rustling noise, which will decrease when the radio station is received. This circuit has very high receiving sensitivity and requires an external antenna.
ck="window.open(this.src)" alt="Click to see larger image" />