Mike Grant wrote: > > Justin Cormack wrote: > > ok, have more or less worked out how to do this. The only thing is what > > frequency these channels are on. I cant work out how to convert from channel > > number to frequency for the uk... > > From http://www.linuxstb.org/dvb-t/index.shtml: > > centre frequency = (UHF Channel Number)*8 + 306 > > This gives you a frequency in MHz. VDR uses kHz (MHz * 1000) and > dvbstream, etc use Hz (MHz * 1000000) so you'll need to pad it out to > the correct length. > > Also note that most channels have an offset from the centre frequency, > which must also be added. You can find these offsets by looking at your > local transmitter info on: > > >http://www.itc.org.uk/uk_television_sector/reception_advice/digital_trans_guide/index.asp?region=show_all > > For example, the Rowridge transmitter has multiplex 1 on channel 23, > offset -167kHz (listed as '-') and multiplex B on channel 32, offset > +167kHz (listed as '+'). No offset is listed as '0'. So, > > multiplex 1 freq in kHz = (23 * 8 + 306) * 1000 - 167 = 489833 kHz > multiplex B freq in kHz = (32 * 8 + 306) * 1000 + 167 = 562167 kHz > > When converting these to Hz, I tend to assume the ITC meant 166.666..kHz > rather than 167kHz so I get 489833334Hz and 562166667Hz instead of > 489833000Hz and 562167000Hz. I don't think that it matters though..
Are these frequency offsets always +/-167kHz? Will that be the same for other countries, too? I'm asking because I would like to make the frequency for DVB-T channels in VDR's channels.conf also be in MHz, and if that offset thing is in any way standardized we could just add another DVB-T specific parameter to cover the offset (like O0 = 0 kHz, O1 = +167 kHz, O2 = -167kHz). I wonder, though, why that offset is necessary, and whether the driver shouldn't be able to tune to a channel at, say, 490 MHz - 167 kHz automatically if it is given an inital frequency of 490 MHz. I mean 167 kHz isn't _that_ far off for a transponder with several MHz bandwith. Or am I missing something important here? Klaus -- _______________________________________________________________ Klaus Schmidinger Phone: +49-8635-6989-10 CadSoft Computer GmbH Fax: +49-8635-6989-40 Hofmark 2 Email: [EMAIL PROTECTED] D-84568 Pleiskirchen, Germany URL: www.cadsoft.de _______________________________________________________________ -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.
