-.-. --.- wrote:
. . .
By the way, due to wavelenght we are playing in the HF, i doubt that can be
realized a true circular polarization antenna for HF spectrum. Maybe
something can be realized on VHF and up. . .

I agree. My experience is that:

1. It's difficult to generate circular polarization in more than two
opposite directions at HF. With something like crossed dipoles fed in
quadrature (sometimes called a turnstile), the polarization is circular
only at right angles to the plane of the dipoles. It's linear to the
sides and elliptical elsewhere.
2. Even after you generate a circularly polarized signal, ground
reflection tends to make it linear. It's difficult or impossible to
avoid ground reflection over an HF path.

Roy Lewallen, W7EL