On Sat, 18 Jul 2009 09:54:43 +0100, "Arfa Daily"
wrote:

Circular polarisation for US DBS, Jeff ? Over this side of the pond, it's
vertical and horizontal polarisation for alternate channels or whatever, but
with the same selection / LNB powering voltages, and additional switching by
22kHz tone, the same.

DirecTV and Dish are both circular polarization.
HughesNet internet is linear (vertical or horizontal) polarization.
FTA (free to air) transmissions are all linear polarization.
Broadcast downlinks (FSS) are all linear polarization.

http://en.wikipedia.org/wiki/Low-noise_block_converter
"Most North American DBS signals use circular polarization, instead of
linear polarization, therefore requiring a different LNB type for
proper reception. In this case, the polarization must be adjusted
between clockwise and counterclockwise, rather than horizontal and
vertical."

This explains it in detail:
http://www.abadss.com/forum/102-faq-how/5880-understand-lnbs-standard-linear-circular-universal-lnb-lnbf-stacked.html



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558