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

Steven Toth stoth at hauppauge.com
Tue Aug 15 19:25:49 CEST 2006

> I suppose it could be a weak signal.  I am using an inline signal meter to 
> aim the dish and it shows a signal.  How about polarization?  It turns out 
> this LNB is Circular only (thank you Steven Toth).  How do I get dvbtune or 
> other szap to use circular (L or R) polarity?  Is this supported in v4l-dvb?
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.


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