[linux-dvb] Re: Polarization in DVB-T?

[Holger Waechtler <holger@convergence.de>]

Nico wrote:
> Hi,
> in frontend.h there's no polariziation parameter for ofdm, yet
> the few stations transmitting DVB-T streams  always specify
> H polarization in their specs.
>
> Is H the only possible polarization for all DVB-T transmissions?
> Here COFDM will be used; is it any different from the OFDM
> used in other countries?
> Will the current drivers have problems with it?
no - polarisation is a pure antenna alignment/type issue - I'm not aware 
of any terrestrial antenna with switchable polarisation.

In any case you can receive all polarisations with a single antenna - if 
the orientation (horizontal/vertical/left-/rightcircular) of the 
transmitting antenna does not matches the one of the receiving antenna 
you will just get a weaker signal with a loss of a few dB. I'm not sure 
about the absolute loss in this situation, maybe it was 3dB, maybe 6dB - 
check the literature or google a little around - I'm pretty sure you'll 
find lots of pages regarding this issue in the 
do-it-yourself-wireless-antenna forums on the web.

Holger



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