On Mon, 2004-05-10 at 10:09, Simon Kilvington wrote: > disclaimer: I only got into this a month or so ago, so this > description may be complete arse... Or it may be completely correct! > scan works by reading the Network Information Table (NIT) that > is broadcast with the DVB-T signal - the NIT lists all the other > frequencies the transmitter broadcasts on and gives a bunch of other > info - I had problems with the transmitter near me (Malvern) because > it is just a repeater for Sutton Coldfield - so it just rebroadcasts > the Sutton Coldfield NIT, but all the frequencies the Malvern > transmitter uses are different so the NIT is wrong. This is exactly the problem I have here in Ipswich. Our local transmitter (Tacolneston) is a bitwise repeat of the Sudbury transmitter but uses different frequencies. I ad a little rant about this almost exactly a year ago on this very list. (subject ``Evil transmitters: a gotcha with the scan program (but not it's fault)''). I think someone pointed out that the transmitter can send ``alternative frequencies'', but its a little dodgy. Actually, I've just read the archives and Simeon Walker gave a very good description on the 17th of May 2003. It would be Jolly Nice[tm] if dvbtune/kaxtv and the others could take a peek at the alternative frequencies specified in the NIT. > what I did was look at the OfCom web site to find what the > frequencies were for Malvern: You youngsters have no idea what its like! Back in the good old pre-ofcam days we had to look it up on a different website where they got one of the multiplexes wrong! Took me ages to work that one out. The excellent sdvbsnoop program can be used to great effect to peek inside all the information lurking inside a multiplex. Hope this helps, Jim. -- Jim Darby <jim@jimbocorp.uklinux.net> The Jimbo Corporation
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