[linux-dvb] Re: Tuning Nebula card to Saddleworth UK transmitter

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Wednesday 22 Sep 2004 11:04, Jukka Tastula wrote:
> On Tuesday 21 September 2004 21:10, Carey wrote:
> > Which i'm guessing means that i'm looking at the wrong frequencies. I
> > randomly tried ./scan dvb-t/uk-BlackHill and that does seem to pick up
> > something which looks like a faint WinterHill signal. Anyway i've output
> > that to a channels.conf with about 10 lines in it like those below..
>
> That makes sense as Black Hill appears to be transmitting BBC on channel 41
> but that's ITV mux on Saddleworth. I don't live in the UK so I'm pulling
> this stuff out of my ... based on the chart's channel numbers (who ever
> thought it'd be a good idea to have Hz accuracy on these frequencies? kind
> of hard to remember don't you think?) you _might_ have some luck with one
> of these (constellation and fec_hi should be autodetected by most if not
> all cards anyway)
>
> T 682000000 8MHz 3/4 NONE QAM16 2k 1/32 NONE
> T 682000000 8MHz 2/3 NONE QAM64 2k 1/32 NONE
> T 682000000 8MHz 2/3 NONE QAM16 2k 1/32 NONE
> T 682000000 8MHz 3/4 NONE QAM64 2k 1/32 NONE
>
> That should be the bbc mux and I'm guessing it's supposed to be able to
> find the other transponders based on that. The frequency isn't exactly
> accurate as I can't possibly guess that. The other frequencies should be
> 634 (itv & c4), 658 (A), 714 (B) , 618 (C) and 738MHz (D). Again I'm just
> guessing based on the UHF channel number. Looking at the numbers I get the
> feeling you might need to add ~170khz but for me at least the nebula can
> find the transponder even if I tune 500khz wrong frequency, it just takes
> a second or two longer.
>
> If tuning to those frequencies doesn't work or destroys your tv card I
> can't be held responsible.

This link might be useful to you:
http://www.bbc.co.uk/reception/tv_transmitters/tv_digit.shtml

There used to be an even better one at the itc.org.uk which gave the offsets 
as well, but ofcom in their wisdom have removed it.

BTW: convert channel number->frequency is:
centre frequency in MHz = (UHF Channel Number)*8 + 306 + offset

where offset in the UK is +0.166666, 0, or -0.166666