[linux-dvb] TT C1500 "new version" problems

Heikki Lindholm holindho at cs.helsinki.fi
Sun Jan 27 22:09:27 CET 2008

Heikki Lindholm kirjoitti:
> Hello there,
> got myself a Technotrend DVB-C C1500 card, which has a TD1316AL/IHP 
> tuner, but the card doesn't really work on Linux - a huge surprise 
> there. It appears, the card is of a newer variety, which has some 
> incompatible component change. Using kernel 2.6.24, from what I've tried 
> the status seems to be:
> - QAM64 channels work, ie. FE_HAS_LOCK but "unc" is very high
> - QAM128/256 channels get only occasional FE_HAS_LOCK, but lose it in a 
> few seconds
> QAM64 high unc value is fixed by letting the corner detection stay on, 
> as reported in
> http://www.linuxtv.org/pipermail/linux-dvb/2008-January/022847.html
> QAM128/256 tuner locking can be fixed by reverting the patch in
> http://lkml.org/lkml/2005/9/4/202
> but "unc" is still at unacceptable levels.

For the record, the two above changes seem the ones that have the most 
effect. On a hardware-wise good setup, the signal levels become good and 
errors are rare. The biggest problem with the card, or the specimen I 
have, at least, appears to be that it's really sensitive to 
interference, eg. if I put harddisks to work (grep "foo" /), error 
levels immediately rise. This was a problem with some early TT 
budget/Hauppauge DVB-T cards as well. I don't think this can be fixed in 
the driver.

-- Heikki Lindholm

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