With Passif 60HZ Filter . (Sensor) Use Telephone Pick-up (380mH) Coil. Out Add BF LM386. Op Amp=741 . For hearing Earth 🌍 Magnetic Field , Build 1 Feet Diameter Coil with 40-42 AWG Wire (1000 turns Minimum or more , connected to Blinded Cable For super Sensitive Antenna.
