Oscillating circuit (coil) are made on a ferrite bar. If you wish to listen long waves winding `1-2` has 135 turns and 3-4 has 20 turns. If you wish to receive medium wave winding `1-2` has 75 turns, and `3-4` has 7 turns (wire used must be CuEm 0. 15mm). In parallel with the winding 1-2 is necessary to connect a 40-400pF variable capacitor. Listen
ing signal is made using high impedance headphones to 1000-2000 ohms, which have a capacitor of 10nF in parallel.