LF: Induction DX?

[Roger Lapthorn <rogerlapthorn@gmail.com>]

If I've asked this before please forgive me....

With all the discussion recently on how to radiate a signal on sub-9kHz I'm left wondrering how far, practically, one could expect to get simply with sub-9kHz magnetic induction using multi-turn loops at each end?  The Cave Radio Group (CREG) may have some answers but I'm not a subscriber so can't read any of their documents. 

It would be quite easy for anyone to generate 50-100W or so and feed this into a largish diameter multi-turn loop. Correctly aligned and with a similar loop at the far end and using decent weak signal processing just what range might be possible using modes like QRSS or WSPR? Has anyone tried this to see just what is practical, simply using induction fields? 

Also, can anyone point me to some webpages with some practical audio frequency induction communication systems? There are lots of references to near field comms for on-body and inter-device comms but I've not found much otherwise.

73s 
Roger G3XBM


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