FSK radio communication below 3 kHz using HAARP ionospheric excitation

The HAARP HF antenna array was employed to modulate overhead ionospheric currents and transmit an FSK signal below 3 kHz for communication purposes. The basic properties of the successfully observed signal at a distance of 37 km from HAARP are presented. The outcomes of the experiment showcase this method of producing lower radio frequency emissions as a viable means of communication with submarines or in underground mines, with possible ameliorations in bit rate or modulation type.