Further 8.97kHz earth-mode tests

All being well, I'll be carrying out some more earth-mode (through ground conduction current) WSPR and QRSS tests on around 1kHz and 8.97kHz in about 10 days time. My aim is to achieve a new personal DX record for the mode using about 4W. My previous best distance is 0.3kms, but I'm pretty certain that with QRSS or WSPR this can be bettered. Remembering an earlier post, 18dB more system gain is needed to double distance using this mode of propagation.  This can be achieved by raising TX power or effectively improving the RX sensitivity, in this case mostly by better filtering and signal processing.