Suggested by a 90s Popular Electronics this circuit is intended to receive volleys or whistles from thunderstorms in the wave range below 20 kHz. The coil consists of 300 turns of wire 26 in a ferrite rod.
This circuit was found in Radio Electronics from the 90s. The circuit can generate signals up to...
Found in English documentation from 1989, this circuit appears elsewhere on this site, taken from...
This circuit is from an 80's documentation, making use of PUTs that are not currently common...