[linux-dvb] Re: Troubles with DVB-C

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Philippe" <gaultier.philippe@free.fr>
> Well, I think that for digital cable, each frequency carrying
> some channels is called a transponder.

No, "transponders" are only used in satellite systems. But since digital
satellite was established first, many were used to calling those things
"transponders" and didn't bother to switch to the correct term when digital
cable and satellite was introduced.

The general term is "multiplex", which means a transport stream regardless
of the specific transmission method.

The specific terms are "transponder" for satellite, and "channel" or
"frequency" for cable and terrestrial transmission.

So if you don't want to bother using the specific term, just always use
"multiplex".

And what you call a "channel" is actually a "service" in DVB terms (or a
"program" in MPEG-2 terms).

> TP02 131.125 [ 9 channels] cannot lock (needs tune delay 2500)
> TP05 155.125 [12 channels] cannot lock (needs tune delay 800)
> TP08 211.125 [13 channels] cannot lock (needs tune delay 500)
>
> Total 211 channels on 21 frequencies
> (or multiplex or transponders, call it the way you want)

211 services on 21 multiplexes (or channels).

> I tried to change the pwm value (ves1820 specific) but it seems
> that it does nothing,

The PWM value is only for the Fujitsu/Siemens DVB-C card and has no effect
on any other card.

> I always have :
> DVB: VES1820(0): AFC (-4) 26855Hz

Do you also have this on the 3 channels mentioned above?

> As I told you before, I do not understand why my official decoder
> works without any trouble...

What do you mean by "official decoder"? Another piece of hardware? The
reception hardware you're using in your PC may have different
characteristics, or rather "weaknesses" at certain frequencies. If you're
not getting any better results using the manufacturer's official Windows
driver, chances are the hardware can't do any better.

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany