[linux-dvb] Re: Tuning problems with TT DVB-C 1500 (saa7146 + stv0297) and QAM128

Patrick Boettcher patrick.boettcher at desy.de
Sat Aug 20 13:50:28 CEST 2005


Hi,

On Sat, 20 Aug 2005, Tero Saarni wrote:
> Patrick Boettcher wrote:
>> The CableStar2 (DVB-C variant of the AirStar2 and SkyStar2) is another 
>> budget DVB-C card with stv0297 as demodulator. When I wrote support for 
>> this card, the stv0297-driver was already in dvb-kernel, but I could not 
>> use it for this card (the code I got from the vendor and the code from 
>> dvb-kernel has simply been too different). So I started to rewrite the 
>> stv0297-driver nearly from the scratch with the help of the vendor-source.
> ...
>> Why I'm writing this? So, a month ago a guy from Finland got such a card 
>> and wanted to use it with QAM128. At first it was not working, but then I 
>> found out, that turning off the "corner edge detection" fixes the 
>> QAM128-tuning-issue (that's why my proposal, which didn't help, though).
>> In fact the QAM128-tuning was as fast as tuning to QAM64 (< 500ms).
>
> Dvbshop product page says that CableStar2 supports only QAM 64
> demodulation http://www.dvbshop.net/product_info.php?products_id=211.

Do you really believe what shops are saying about the quality of a board?

In times where even popular computer magazines (at least here in Germany) 
compare the quality of DVB hardware with the bundled (third party) 
software, I think it gets really hard for the user to make the right 
decision.

> Maybe this is then not valid?  Can it be used with QAM 128 when
> running your version of the drivers?

Anyway: Yes. I had the chance to fix the QAM128 support for the Cablestar2 
ssh'ing a to a PC of a Finish user who wanted to use QAM128 and it worked 
after disabling corner detection.

The cablestar is not supported in current dvb-kernel CVS, but only in the 
archive downloadable from my website. I really would love to have the 
support for it in dvb-kernel, but I don't have time to include the change 
to dvb-kernel currently and I don't have the other stv0297-based cards to 
test compatibility.

Maybe then QAM128 would work correctly even for the TT stv0297-based 
cards.

regards,
Patrick.

--
   Mail: patrick.boettcher at desy.de
   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/




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