[linux-dvb] Re: grr.. Any DVB-T adaptors which work reliably?

[Ragnar Sundblad <ragge@nada.kth.se>]

--On den 30 juni 2003 22:44 +0100 Edward Wildgoose <ed@wildgooses.com> 
wrote:

> I just can't get this wretched TT DVB-T 1.2 card to work reliably
> at all!!
>
> Has ANYONE managed to get a DVB-T card working with VDR in a completely
> reliable way?
I have had a bunch of problems with my TT DVB-T 1.2 too.
It now works quite reliably, but it still picks up of
interference from somewhere, I have audio clicks and picture
problems on some, but not all, channels. I very seldom have
firmware craches now.

- At first I had lots of problem with just getting it to
tune at all. I think that it needs a very stable 12V that also
should preferably be a little bit above 12V, not 11.8V or lower.
I bought a new power supply and moved away a 12V fan connection
from the main board and got better results with the card.
I think the DC/DC converter for the tuning power is to weak,
it is some homebrew with a 555, and the voltage dips at higher
frequencies.

- With a oscilloscope I see strange spikes on the I/F line from
the tuner to the demodulator. They are spaced at about 18,3MHz
which happens to be a third of the demodulators clock frequency.
Though it could be something else that I pick up with the scope
some strange way, I suspect that it is real and that it is a
hardware bug. Sadly, data sheets on these things are hard to
get, I suspect that there is a biasing problem on the demod
input or something like that, at least I would like to have
enough documentation to be able exclude those ideas that I have.

- I have lines traveling down the tv screen when using the
composite output from the DVB-T card. I heard from another guy
that has both a DVB-T and a DVB-C that he has the same on the
DVB-T, but that the DVB-C is OK.

- When I have the driver loaded/firmware booted/whatever does it,
my last tv in the antenna chain gets vertical or sloping lines
over the screen on analog channels. When I unload the driver,
the lines disappear.

All in all, I am not very impressed by this card.


Now when I have some DVB-T friends on the line:

Usa-x says that their DVB-T 1.2 cards look like this:
<http://www.usa-x.org/1shop/popup_image.php?pID=7&language=en>
My 1.2 card does not look like that, it has an ALPS tuner and
a SP8870 demodulator on the main board, like the one here:
<http://www.technotrend.de/english/products/pcproducts2-2.html>.
Does anyone know if the design has changed and they don't
really mean 1.2, or if they just have wrong picture?

I have also been thinking of bying a Nova-T to see if I at least
can get better reception with that. There is a possibly new one
called 1.3, which could be studied here:
<http://www.usa-x.org/1shop/product_info.php?cPath=3&products_id=34&languag
e=en>, pdf here: <http://www.usa-x.org/1/T1300.pdf>.
This one looks like it could at least be fitted with a
CI connector (yes, some DVB-T channels in Sweden are encrypted).
Does anyone know if one gets this card if you buy a Hauppauge
Nova-T, or if you get one without a CI connection?
Does anyone know if this card is supported by the driver?
Any recommendations?

/ragge




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