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

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Nico" <nsabbi@tiscali.it>
> 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.

That's how you would install your antenna. Unlike satellite reception, I am
not aware of any hardware that would allow control the polarization of your
aerial antenna.

> Is H the only possible polarization for all DVB-T transmissions?

No, it can be transmitted with vertical polarization just as well, and this
is actually being done here in Berlin: We have three transmitter locations,
of which two are a little bit closer together. Of the 7 channels used here,
3 are transmitted by both of these, but one transmitter will use vertical
polarization instead of horizontal to avoid interference.

But it doesn't seem to make any difference: My antenna is installed
horizontally and can receive all channels perfectly fine (I am located
between the mentioned two transmission towers).

> Here COFDM will be used; is it any different from the OFDM
> used in other countries?

Unless I'm mistaken, this is one and the same. OFDM is the transmission
method, COFDM the coding used on that transmission method. ETSI 300 744
exclusively mentions OFDM, never COFDM.

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



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