I found this interesting article:

It basically describes non radiant communication using the sole electric field on 9kHz with a communication range of up to few hundred meters
I was able to do some simulations for higher frequencies (80m band) with a slightly different setup and I would get a few 1000kms in theory.
Ofcourse building and testing is the way to verification and I should be semi-optimistic about this.
What are your toughts ? Is achieving long range possible using this technique ?