[mythtv-users] Signal strength reported by tuner card?

[Andrew Herron]

On Mon, Sep 28, 2009 at 12:43 AM, Brian Wood <beww at beww.org> wrote:

> On Sunday 27 September 2009 17:31:29 George Nassas wrote:
> > On 2009-09-27, at 3:33 PM, Brian Wood wrote:
> > > On Sunday 27 September 2009 12:23:17 Andrew Herron wrote:
> > >> I have an equivalent STB hooked up as a benchmark the DVB card
> > >> seems to
> > >> always be less sensitive and to deliver a less stable & lower quality
> > >
> > > Assuming your assertion to be correct (and I have no reason to doubt
> > > your
> > > word), I can't see any reason why it should be so.
> >
> > Could it be electrical/RF/??? noise from other components within the
> > PC? A friend has a similar problem with a PVR-250 card where the TV
> > gives a much better picture even though they're right next to each
> > other, split off the same cable etc.
>
> Anyone designing a card intended to go into a PC knows, or at least should
> know, what the environment is like inside a PC case, and should take
> measures
> to combat any RF floating around, or inverter hash on the DC rails etc.
>
> A PC card should work as well as a standalone STB, or at least should be
> capable of working as well, assuming a good quality PSU, proper
> configuration
> etc.
>
> I can get my PVRs to produce pictures that the average non-technical viewer
> can't tell from the signal being produced by the TV set itself with a
> direct
> CATV feed. I can see some artifacts, after all you are looking at an
> encoder
> on the PVR, as opposed to the encoder at the TV station or network, and
> presumably the one at the TV station is of better quality than a sub $100
> card.
>
>
I agree with your assertion about the tuner hardware being unlikely to be
'better' than the tuners in DVB cards. But what I see repeatedly is that
with a PC tuner using the same aerial or Sat feed as a commercial STB we get
a less 'reliable' picture in that on the PC we will often see dropout
blockiness in the received stream which we do not see on the STB. Its as if
the PC cards tuner is less 'sensitive' and therefore we see digital
artifacts that we do not see on the STB. I have seen this in numerous
installations so its not specific to any particular location or brand of PC
DVB card.

Andrew
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