[mythtv-users] How to limit 2xDVB-S (+DiSEqC) to 1 LNB at a time?

[Jelte Veldstra]

On Sat, Apr 25, 2009 at 12:08 AM, David Lister <foceni at gmail.com> wrote:

> Hello, please HELP! :)
>
> I guess this is quite a common setup, but I couldn't find anything
> relevant in the docs nor on the mailing list. I have 2x TeVii S640
> DVB-S2 cards (C1, C2). C1 input = cable, C2 input = C1 loop-out.
> Cable connects to one port of a DiSEqC multiswitch (2 LNB's).
>
> C1 -+-----[switch]----+- LNB1 (19.2E)
> C2 -+                 +- LNB2 (23.5E)
>
> MythTV DiSEqC config works, I have all channels, LNB switching rock
> solid. If I had just one card (or two cards in two switch ports),
> the configuration would be finished. Thing is, I need to tell MythTV
> that there is ONE DiSEqC switch port shared among BOTH cards, i.e.
> MythTV can access only one LNB (aka "Video Source"?) at a time.
>
> Capture cards:
>  [DVB : 0]
>    DiSEqC: switch, 2 ports -> (LNB, LNB)
>  [DVB : 1]
>    DiSEqC: switch, 2 ports -> (LNB, LNB)
> Video sources:
>  S19 [EIT]
>  S23 [EIT]
> Input connections:
>  [DVB : 0] -> Port 1 (LNB) -> S19
>  [DVB : 0] -> Port 2 (LNB) -> S23
>  [DVB : 1] -> Port 1 (LNB) -> S19
>  [DVB : 1] -> Port 2 (LNB) -> S23
>
> I thought having just 2 video sources should take care of my
> setup, because with two independent cables I would probably
> have 4, one for each accessible LNB. But it doesn't seem to work
> this way. Unfortunately, I can't manage this exclusion manually;
> I use custom rules searching all over the table and I'd have to
> screen every recording for "undetectable" LNB conflicts...
>
> 1) How to make sure MythTV is using only one LNB on both cards
>   at a time?
>
> Second question is about input groups. With HVR-500 everything
> worked out of the box, but I'm having difficulties with DVB-S.
> Each card -> source connection has "Input Group 1" and "Input
> Group 2" properties.
>
> 2) Could this be used for my shared DiSEqC switch port problem?
> 3) How to set both input groups for 2 tuners (per 4 multirec)?
> 4) Anybody has links with good info on input groups (apart from
>   the documentation)?
>
>
> Thank you in advance!!
>
> --
> David Lister
> _______________________________________________
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> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>



Not that I have a lot of experience with DVB-S setups and DiSEq, but it
seems to me that on the adapter (or settopbox) "side" of the switch can only
be a single tuner. It seems to me there are only two solutions:

1) Remove the switch and run two coax cables from each tuner to each LNB (1
to 1 connections)
2) Make the LNBs twin LNBs, add a second switch and have both tuners connect
through a switch to these twin LNBs

The first one would be the least expensive, but the second gives more
flexibility in recordings. Your current setup can maybe be used if you use
inputgroups:

http://www.mythtv.org/docs/mythtv-HOWTO-12.html#ss12.6

Regards,


Jelte
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