Rick, Horst, et al,

 

I am unsure of the "official" UK position regarding operation below 9kHz. Back in the late 1960s a Test and Development Licence was required and I held two around 1970 (G9BIB and G9BGU) for "earth mode" experiments between 0 and 50kHz.  If you ask OFCOM I suspect they will require you to have a special permit (NoV), HI.

 

It would be very interesting to know just how far amateurs could communicate below 9kHz. Amplifiers of 500-1000W coupled with the very best in weak signal modes and widely spaced grounded electrodes or large induction loops might result in the 10km barrier, achieved some years ago, being exceeded. ERP is meaningless at these frequencies as virually nothing will be radiated: communication will be by conduction through the ground or by induction.

 

73s

Roger G3XBM