[mythtv-users] DVB-S cards

Robert RobertCL at iname.com
Fri Apr 6 15:51:32 UTC 2007

Peter Spikings wrote:
> Hi,
> I've just realised the possibility of using DVB-S card(s) instead of the 
> PVR-250 + Digibox combination (I'm in the UK). I'm a bit unsure however 
> on the details of this would work however.... I'd like to be able to 
> record two or more channels at once (or otherwise I may as well stay 
> with my current setup!).

Ok, here goes.  I've recently setup a Mythtv system using DVB-S in the 
UK, so I should be able to answer most of these!

> * Presumably I'll need as many cards for this as I want to record channels?

Simple answer: Yes.  Slightly longer answer: each demux on DVB-S 
contains a number of different channels so you can potentially record 
many-at-once with a single card so long as all channels are on the same 
demux.  This doesn't work in mythtv yet, but there have been a few mails 
about getting donations together to pay someone to do this.

> * Can the LNB on my satellite dish (was installed by Sky in late 2003 
> but don't know the make) supply two (or more) cards using a splitter?

Short answer: No.  For each demux you want to record from, you need an 
LNB.  So in essence you need a dual / quad LNB.  I believe the newer Sky 
LNBs have multiple outputs for things like Sky+.  Splitters on satellite 
don't work in the same way as splitters on ariels - you can split the 
signal, but everyone connected to the split has to watch the same channel.

> * Is the Sky supplied EPG data as good as the RadioTimes data I now get 
> through XMLTV?

I'm not using the DVB-S EPG data - I've only ever managed to get now and 
next. (But I've not got a sky box).  You can still use XMLTV though.

> * Are there any recommendations for cards to use? (I'm using Gentoo 
> hence using a recent kernel is not a problem)

Err.  Not sure.  Personally I have an hauppauge  HVR3000 - it's not very 
well supported, the drivers are experimental and as a result I'm 
currently stuck at kernel 2.6.18.

> * I think my dish may have been blown slightly out of alignment, 
> sometimes (but not very often) I experience break up of the signal, will 
> that be worse using DVB-S cards? (I'd try and fix that but the dish is 
> mounted pretty high and I don't have access to a ladder!)

I had a lot of problems with this.  I found that my NVidia graphics card 
interfered with the capture card.  I didn't think it was to do with dish 
alignment as my set top box worked fine.  However I eventually realigned 
my dish and the problems went away.  I think as a general rule if you 
can improve the incoming signal you should!

> * I currently have no Sky subscription, is it possible to get the BBC HD 
> channels without one? Do you need a special type of card for this? (This 
> is academic atm as I don't have a HD TV but I want to future proof my 
> Myth box).

Yes.  I can record it.  It's currently broadcast in DVB-S  (not the 
newer DVB-S2 which is intended for HD I believe)  But it's H323 and you 
need a fairly powerful machine to play it back.  (Mine is too slow :-(  )


More information about the mythtv-users mailing list