[vdr] Re: Problems while switching channels -> seems to be a diseqc problem

["Reinhard Walter Buchner" <rw.buchner@freenet.de>]

Hi Oliver,

> > Hmm, might be interesting. Do you think some DVB
> > cards generate sloppy signals?

> I think that there are too much problem reports
>about DiSEqC  to be ignored.

Full Ackn.

> I'm using a full DiSEqc sequence without any voltage/toneburst 
> commands. Even with this setup switching is not very reliable,
> unless I add some retransmissions. It's just a work-around.

Strange, while I don't have a switch, I do have a motor. After
my workaround and later Klaus's new tuning routine, it runs
w/o a hitch at all. Even rapid switching of channels (lots of
DiSEqc commands on the line) between satellites doesn't
throw the motor or the LNB reception off (my card is a Rev
1.6). The voltage on my card is slightly off spec (12.5V and
17.1V), but it works. One of my mods to the VDR code is the
possibilty to add 0.5V to the LNB line. Sadly enough not all FE
support this feature (my mod checks this and reports if it is
possible with one's particular FE) eventhough all LNB PSU
Chips support it (a la datasheet).

> *sometimes* the *first* DiSEqC command sequence [...] doesn't
>work. So I added a dummy DiSEqC command at the begining of
>the line and now it seem to work...

Interesting. Did you try to increase the Wtime before and after
sending the DiSEqC command?

> There are many possible causes:
> - too low/high voltage of the 22kHz signal
> - wrong frequency
> - glitches in the signal
> - bad waveform
> - tone-burst too short/long

With exception of the voltage that was what I meant with
"sloppy signals"

> Basically, DiSEqC is nothing else than turning the 22kHz
> tone on or off.

Ack.

>With the full-featured cards this is (unfortunately) done by 
> the AV7110 firmware...

Yes, true. It seems (just like CAM support ;-() to be a weak
point in the FW. However, it is most likely a timing problem
with DiSEqC command sequence which prevents Convergence
from implementing it directly into the driver code (and taking
it out of the FW).

Greetz,
Reinhard


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.427 / Virus Database: 240 - Release Date: 06.12.2002



-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe vdr" as subject.