[linux-dvb] Re: diseqc switch recommendation

[Vladimir Shved <vshved@logistic-systems.com>]

> -----Original Message-----
> From: linux-dvb-bounce@linuxtv.org [mailto:linux-dvb-bounce@linuxtv.org]
> On Behalf Of Josef Wolf
...
> I'm still not sure I understand the difference.  For four LNBs (in
> germany)
> one would usually install a 17x4 or 17x8 switch (four inputs per LNB) and
> have quattro-LNBs (do not confuse with quad-LNB) attached to it.  I have
> such a setup and it works great.

I did not know that such thing, like 17x4 switch, even existed until now.
Thanks for pointing that out, now I need to find someone who would be
willing to send it to US ..:)

> One of the answers to the mentioned article brought up the speculation
> that the hw_sections setting could have some timing impacts to the
> firmware which in turn could make diseqc generation fail.  Diseqc
> generation seems to be implemented in firmware, not in hardware.

That is very possible, I'm not familiar very well with internals. Try newer
firmware, there was new firmware released rc8.

> You have FF cards, right?  As I wrote in my previous message, the problem
> that diseqc don't work at all with 2.4 kernel was in conjunction with
> _budget_ cards.  Please re-read my previous message carefully.  I was
> talking about _two_ problems:
> 
> 1. Budget cards don't send diseqc at all with 2.4 kernel.
> 
> 2. FF card sends commands _unreliably_.  This problem is _not_ dependant
>    on kernel version.  This problem seems to be similar to your problem.

I've used SkyStar2 2.6c and 2.3 revisions too, and tried those only with
kernel 2.6, stv0299 and mt312 frontends, the stv0299 frontend driver wont
load on 2.4. The diseqc switching was flawless on both cards, if you are
sure you don't have any hardware/wiring issues, possibly your machine is too
slow or something is slowing it down? Maybe try kernel 2.6?
 
> > Maybe you have bad switch, or signal does not reach the switch,
> 
> Definitely not.  For two reasons:
> 1. I can make it work/fail without changing the switch.
> 2. My diseqc-tester shows failure, too.
> 
> > or software sends wrong diseqc commands,
> 
> Oh, I tried with:
> 
> - VDR
> - szap
> - dvbstream
> - vls
> - vlc
> - I even wrote my own little test application and posted the diseqc-
> snippet
>   into this list.
> 
> All of them show the same symptoms.  Therefore I don't think it is a
> problem in the application code.
> 
> > or there is lots of noise in cabling which causing to corrupt diseqc
> > commands.
> 
> But how comes that cabling noise is dependant on the kernel I run?

It has nothing to do with kernel, it's the signal that can't reach the
switch. Maybe extra noise in cables? Or weak signal or other issues.