[linux-dvb] Circular polarization

Robert Schlabbach robert_s at gmx.net
Fri Mar 31 22:17:07 CEST 2006

From: "DUBOST Brice" <dubost at crans.ens-cachan.fr>
> In regular cards there is (in general) two orthogonal linear polarizers.
> So you can try with any linear polarization but you'll get -3dB on your
> signal

AFAIK there are *no* polarizers on the card. The polarizer is contained in
the LNB. So you only need an LNB with circular polarization. If that LNB is
controlled with the same signals as common LNBs with linear polarization
are (where +13V sets vertical polarization and +18V sets horizontal
polarization), you can use the same drivers without changes, and only have
to know what circular polarizations horizontal and vertical correspond to.

Robert Schlabbach
e-mail: robert_s at gmx.net
Berlin, Germany

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