The "Software Defined Antenna"

[ChrisSmolinski]

https://sd-antenna.com/

[Charlie_Dont_Surf]

Diversity reception, even electronically steerable diversity reception, is not anything new and the website refers to this, though I don't agree that until now that the elements of the antenna had to be larger than the wavelength. Simple arrays of whip antennas have been used in this manner and they aren't longer than a wavelength at HF. Even the entire array does not have to occupy more than a wavelength. People have made arrays of dipoles (which are half of a wavelength long as a fundamental principle) do similar things.

In any case, this would rely on the directional characteristics of small HF receive loops. I don't have any real experience with them other than for local noise pickup, where I am not terribly impressed by the directionality. How much nulling can be achieved with a small loop at HF?