i am not sure i would agree that this has been discussed before. this is not simply about use of RF (microwave, mmwave) for HFT. as i understand it, that kind of thing typically involves COTS radios and conventional dish antennas.

this instance appears to involve longer-range links and SDRs (in this case, the ettus USRPs).

Yes, well said. I think you're making an important distinction. Shortwave is old technology, but combined with SDR, this is a novel application of it AFAIK.

A microwave radio setup to the nearest populated area gave my rural-living parents modern internet a few years ago. It’s not the same scale but the same idea! It’s far and away better than satellite.