[mythtv-users] tuning of channels woes - some lock, some don't

[Mario Minati]

Hi,

I have trouble to setup the backend right.

My backend has two budget dvb-s cards (skyStar2, tvStar) both properly 
detected by ubuntu 7.04.

I have one dish with two quad-lnbs (for astra / hotbird) connected to a 
multiswitch with 8 inputs and enough output for every room (time before 
mythtv).

My slightly old vdr is running fine, but due to a higher WAF i decided 
to switch to mythtv.

I think i have problems to setup the videocards, especially the diseqc 
part accordingly. At the moment i just set it up with a single universal 
lnb and without a switch as that gave me the highest signal strength.
Is that correct?

Now the locking problem which keeps me busy googling for more over a 
week now:
All the channels on Astra are found with dvb-tools scan utility as 
expected. I can even szap the channels, the locking is achieved right 
away. But in mythtv's setup only some channels / muliplexes are locked. 
Why is that?
Does mythtv expect a higher strength than szap? (The strength and snr is 
between 50 and 70 for the channels that don't lock.)
Or might it be a problem with the diseqc setup?
It doesn't seem to be a problem of the dvb card, I have three different 
cards and the problem stays the same.
Or do I have to get someone for a better alignment of our dish?

Any help is really apreciated as I have no more idea where to look at.
Thank you,

Mario