[Ground-station] Are Multi-Carrier Data Modes Illegal in Amateur Radio?

[Jan Schiefer]

Is there somebody planning to experiment with OFDM-like signals for ham radio, or is this all purely hypothetical?

What I would find more interesting is multi-band carrier aggregation on HF. For example, simultaneously sending part of the signal on 80m and part on 40m, with some smart coding based on propagation characteristics at the time of the transmission. In theory, this should give you a pretty robust signal on e.g. NVIS. 

Would something like this be subject to the same questions as far as the legality goes?

And I am sure there is another can of worms on this shelf with the label “MIMO” on it. Maybe let’s keep this one where it is. 

Cheers, 
    Jan, ac7td