[vdr] Re: automatic channel scan

[Christian Berger <einStein@donau.de>]

Steffen Koch schrieb:
> 
> Christian Berger wrote:
> > Ok, then you always use the NIT for every transponder you are turned in
> > anyhow, just like the EPG. You should have at least one channel
> > programmed for every transponder to let that work efficiently.
> Is there an information on the satelite about transponder frequencies?
> If so you only have to tune one "range" to find one such transponder and
> then get a complete transponder list to synchronize tuning with...

I don't know, but there aren't really a lot of possibilities.
Transponders on satellites are usually fixed and known long before the
satellite is even sent up. Most stations simply transmitt at the center
of that transponder with different symbolrates. So maybe you'd have to
try 1-5 attempts to find something on those transponders. However,
especially on Eutelsat there are some 72Mhz transponders. Those are
used, for example to transmitt 2 analog channels at different
frequencies, or an analog channel and a digital signal, or maybe 2
digital ones, or several low bandwidth ones (really makes sense in many
situations). Those channels would be hard to find, and might require
about 1-20 attempts to find anything.

I personally don't think a transponder frequencies transmission is
possible. There are many uplink stations, so each of those stations
would have to have a complete, updated (think of those 72Mhz
transponders) list of channels. This would even include little
remote-truck uplink-stations which don't even have internet access.

Well one idea would be this, (I have no idea if that would work) we
really sweep over the whole frequency range, but only try to find out
the signal strength (we don't even try to sync). Then we try to find
peaks in there which probably are transponders. From the width of those
peeks we might be able to guess the symbolrate.

But even if we try to sync to some frequencies, we might find out the
configuration automatically. We just try out some frequencies we know of
and then try to figure out what kinds of LNBs the user has, and also how
DisEQ is connected. (Not all people have Astra on A and Eutelsat 13°E on
B)

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