[vdr] Re: Finding channels

[Gavin Hamill <gdh@acentral.co.uk>]

On Monday 06 January 2003 3:12 pm, you wrote:

> I've no idea what a PAT or SDP is though?

Thinking about it it was PAT and PDT ... my guess is 'Programme Allocation 
Table' ... it makes sense, because if dvbtune -i doesn't work, that's the 
error I get :)

> Aha, right. So does the fact the frontend and a few other bits and
> pieces lock, imply that it is tuned to a digital channel and that it's
> the QAM setting or Symbol Rate that's wrong?

<nod> :)) You may also need to set stuff like guard interval as well, but it 
should only really be a matter of knocking some simple shell script / perl 
script to cycle through each combination of variables for each frequency you 
get a "HAS_VITERBI HAS_SYNC" lock on...

> > In a cable system, I would expect QAM128 or even QAM256 to be in use,
> > since the signal strength is almost guaranteed to be perfect...
>
> Heh, not judging by the state of the analogue service ;-) What would be
> real handy would be for an NTL engineer to pop up about now and say 'we
> use x y and z'.... <pause>.... bugger.

Not a chance =) I doubt most of ntl's "engineers" would know how to subscribe 
to a mailing list let alone have any kl00 as to the tech specs of the systems 
they maintain.

> > The Beeb dropped from QAM64 to QAM16 which dramatically reduces the
> > number of
>
> That's my other project :-)

Heh :)

> presumably the AGC in the, receiver drops the digital signal to the nosie 
> floor.

Those damned nosie floors - gotta watch 'em ;)

gdh


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