archive: Re: SETI: Polarization Modulation

Re: SETI: Polarization Modulation

Lloyd Doering ( dewitt@bellsouth.net )
Sun, 06 Sep 1998 21:39:34 -0500

> Polarisation modulation would have at least the same spectral occupancy
> as amplitude modulation, as it is equivalent to amplitude modulating two
> orthogonally polarised carriers.

Ah, yes, I see that now. Had to think about it a good while. Thanks. I
suppose the bandwidth would be a strong function of the wavelength and the
rate of rotation?

> > average radio telescope, do they monitor polarization?
>
> It would certainly be polarisation sensitive, although it would simply
> convert the polarisation to amplitude. I seem to remember though, that
> some radio astronomy objects do exhibit polarisation, so controlled
> polarisation might be useful, it might also help reject local sources.

So, are there natural sources of circularly polarized radiation? Perhaps from
Sol?
Is it practical to put two dipole detectors in one feedhorn? Or perhaps even
a series, and switch them in and out, say in pairs?