[linux-dvb] Please see if you can help: Twinhan VP 1025 DVB-S PCICard

Dave Schile daveschile at hotmail.com
Tue Aug 15 19:52:10 CEST 2006

>I don't fully understand the real electrical/RF implications of circular 
>left/right vs linear horizontal/vertical other than to say that it's 
>related to how the signal is sent (polarised) from the satellite (it's 
>polarisation) and that you have to have a matching LNB of the same 
>polarisation. In some cases I've been able to receive circular right with a 
>H/V LNB but that was a rare exception, circular left never worked. I'd say 
>buy a linear H/V LNB if your goals are to tune to H/V feeds.
>I'm not suggesting this is your only issue but it's certainly one of the 
>most important. If you have access to a spectrum analyzer when you could 
>see very quickly the L-band representation to see whether the LNB is 
>down-converting correctly, or whether you have a tuner related issue.
Thanks, Steve.
I was getting confused because it appears that even if you specify R or L in 
channels.conf file, the response from szap still only shows V or H.
Other documentation that I found says that circular right is activated on 
the LNB with 13 volts, the same as linear vertical would be activated.  
Circular left is activated with 18 volts the same way linear horizontal 
would be.
Does that sound correct?
I am now starting to think that possibly the signal I'm trying to tune to is 
too weak.  I am only using a small 18 inch DirecTV dish.  Any insights on 

Thanks much.

More information about the linux-dvb mailing list