NE555 VLF transmitter

[WM6]

Simple VLF transmitter with aerial coil wire antenna and changeable frequency can be build using wide available NE555. Not with ideal sine wave but usable.

Potentiometer should be, for more precise frequency selection, multi-turn one (if possible), but not required.

Antenna coil data: outer coil diameter >22cm, wire diameter 0.25mm, coil resistance >33 Ohm, number of turns approx 111, inductance about 5mH, wire length needed about 80meters.

PCB dimension 2.1" x 1.6".