From: "Andrew de Quincey" <[EMAIL PROTECTED]> > With the new code I'm not able to lock on 11747 at all. But.. as I > was despairing of things to try, I tried turning inversion ON. > Now I can lock on to that signal perfectly (but none of the others, > 'cos they require inversion OFF). > > Can someone please explain what would cause this?
DVB-S inversion is one thing I haven't quite figured out yet. A signal will be spectrally inverted if you downmix it with a LOF > target frequency. But DVB-S uses zero-IF, i.e. LOF = target frequency (where LOF is actually two-stage; first LOF is in the LNB, second in the tuner). So what happens when the LOF is slightly off so that it is above the target frequency...? According to the Hotbird 2 Frequency Plan: http://www.eutelsat.com/satellites/pdf/Frequency_plans/fp_hb_2.pdf The exact frequency of this transponder is 11746.66MHz. I wonder if that makes any difference? With 250kHz step size, you should be able to tune to 11746.75 or 11746.50MHz. Could you try these and see if it makes any difference wrt spectral inversion...? It could also be that this broadcaster is delivering an inverted signal... Regards, -- Robert Schlabbach e-mail: [EMAIL PROTECTED] Berlin, Germany -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.