two dvb-s tuner cards one cable

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leemarrett

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#67424 1-Sep-2010 16:57

Hi there,

I'm getting conflicting information from people and I need this cleared up.

I'm putting an HTPC together. I can't get a terrestrial signal so I have to go with DVB-S freeview. I'm installing Windows Media Centre 7 on it.

One of the things I want to be able to do is watch one programme while recording another on a different channel.

To do this, I bought two DVB-S capable PCI cards (http://www.hauppauge.com/site/products/data_novasplus.html)

That, I thought, based on a couple of chats I had with people, should do the trick. However, I put the question to the Hauppage forums, and THEY say you need two cables to get them working how I want. (link to the forum post: http://www.hauppauge.co.uk/board/showthread.php?t=20979)

Naturally, this sucks, and I dont want to have to put another cable in. I hate cables.

But then I spoke to someone else who has the same set up (two cards, DVB-S, one cable, splitter) and they say it works fine.

So, WTF? Who's right? Why do Hauppauge say differently?

Any light you could shed on this would be awesome.

Lee

Nety

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#375388 1-Sep-2010 17:39

Well you do need two cables (one for each card) BUT you can achieve that but putting a splitter in just before the cable gets to the HTPC and have two short cables then going to the cards.
One thing to keep in mind is to make sure the splitter supports passing power on all connections. Some only take power from one connection which will cause problems.

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RustyGonad

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#375389 1-Sep-2010 17:39

You need a splitter, and a couple of short cables to go to each card.

Main cable goes to splitter, short cable from splitter to each card. Get a dual power pass slittter.

Thats it.

mcraenz

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#375409 1-Sep-2010 18:09

Yes but keep in mind that both cards talk to one LNB at the dish. you can't tune both vertical and horizontal at the same time. So if you schedule a recording on Freeview(H) and on SBS(V) at the same time you will have a problem. E.g. The SBS schedule starts and uses the first card which powers the LNB at ~13 volts (Vertical) next the Freeview schedule starts and uses the second card which up's the LNB to ~17 volts (horizontal) and the SBS recording will fail. Not an issue if you're only using Freeview but something to keep in mind.

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leemarrett

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#375591 2-Sep-2010 09:20

Thanks for all your responses -- it's great to hear this. Unfortunately the guys on the Hauppauge site are telling me you're wrong!!!

http://www.hauppauge.co.uk/board/showthread.php?p=97625#post97625

Maybe this is a difference between UK DVB-S and the NZ Freeview DVB-S?

CYaBro

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#375617 2-Sep-2010 10:22

Well I can tell you that they are wrong!
I have that exact setup at home, one cable from sat dish to splitter then two short cables from splitter to the two Nova-S cards in server.
I only watch Freeview and not SBS so it works well.

Opinions are my own and not the views of my employer.

xarqi

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#375618 2-Sep-2010 10:23

A cable can carry the signal from one transponder/polarisation at a time. In that signal can be many channels. If you want to record several of those channels, software permitting, you can.

If you want to record two (or more) channels that differ in transponder or polarisation, there is no way you can do this with one cable coming from an LNB, no matter where or how many splitters you install.

Freeview is broadcast on TWO transponders. With just one cable, you should be able to record, for example, TV1 and TV2, or TV3 and Prime, but not TV1 and TV3, since TV1 and TV2 are on one transponder, and TV3 and Prime on the other.

SBS comes off a different transponder with a different polarisation. If you want to be able to record, say TV1, TV3, and SBSHD, you'll need THREE cables from the LNB.

[Mod (N8): Some info in this post is not correct, user has posted an update below]

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xarqi

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#375620 2-Sep-2010 10:27

CYaBro: Well I can tell you that they are wrong!
I have that exact setup at home, one cable from sat dish to splitter then two short cables from splitter to the two Nova-S cards in server.
I only watch Freeview and not SBS so it works well.

But can you watch/record a channel from one transponder at the same time as you record a channel from another one? I think not.

CYaBro

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#375621 2-Sep-2010 10:31

xarqi:
CYaBro: Well I can tell you that they are wrong!
I have that exact setup at home, one cable from sat dish to splitter then two short cables from splitter to the two Nova-S cards in server.
I only watch Freeview and not SBS so it works well.

But can you watch/record a channel from one transponder at the same time as you record a channel from another one? I think not.

Yes I can.
In fact, because I use MediaPortal, I could record / watch all Freeview channels at the same time.
Never done that though but have recorded 3 channels while watching a forth at the same time, TV One, TV2, TV3 recording while watching Prime.

Opinions are my own and not the views of my employer.

xarqi

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#375626 2-Sep-2010 10:34

CYaBro:
xarqi:
CYaBro: Well I can tell you that they are wrong!
I have that exact setup at home, one cable from sat dish to splitter then two short cables from splitter to the two Nova-S cards in server.
I only watch Freeview and not SBS so it works well.

But can you watch/record a channel from one transponder at the same time as you record a channel from another one? I think not.

Yes I can.
In fact, because I use MediaPortal, I could record / watch all Freeview channels at the same time.
Never done that though but have recorded 3 channels while watching a forth at the same time, TV One, TV2, TV3 recording while watching Prime.

OK, well all I can say is that I have no idea how that can possibly work as described.

xarqi

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#375631 2-Sep-2010 10:39

So - is everything from every transponder on a satellite (with the same polarisation) present on the cable at all times, and it's up to the tuner to sift out what it wants?
Some tuners can sift out only one transponder stream; some many.
Is that where I'm going wrong?

RustyGonad

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#375636 2-Sep-2010 10:42

leemarrett: Thanks for all your responses -- it's great to hear this. Unfortunately the guys on the Hauppauge site are telling me you're wrong!!!

http://www.hauppauge.co.uk/board/showthread.php?p=97625#post97625

Maybe this is a difference between UK DVB-S and the NZ Freeview DVB-S?

Ohhh nooo!!!!!! - That means none of my stuff actually works!!!! Ohh crap... I wonder what I've been seeing up until now then...

I better unplug it all now and give Hauppauge a call...

But first I'll take another big sip from the cup of sarcasm.

Unlike in Europe, where there are many hundreds of different transponders on both Horizontal, and Vertical polarities, Freeview in New Zealand (and Sky as well) only use the Horizontal polarity. This makes us very different from them. It also makes it very easy.

If you want to watch SBS, as mcraenz pointed out, well they're on the vertical polarity. It gets trickier. It can still be done, but you will need either:

1. Dual LNB's, Dual cables
2. Dual Polority LNB, and a switch
3. Or manage it via a single power pass switch and an understanding of the software you use (you won't be able to record or watch anything else while recording/watching SBS).

If your not using SBS, just follow the original posts.

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xarqi

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#375651 2-Sep-2010 11:15

xarqi: So - is everything from every transponder on a satellite (with the same polarisation) present on the cable at all times, and it's up to the tuner to sift out what it wants?
Some tuners can sift out only one transponder stream; some many.
Is that where I'm going wrong?

On further thought, I believe this is exactly what's happening.
I was tripped up by presuming that the reason the recorder I had could not simultaneously record channels from different transponders when it could from the same transponder was a fundamental limitation of the satellite system architecture, not yet another egregious blunder on the part of the manufacturers of the box!

I retract my earlier comment about the need for separate cables for separate transponders, apologise for any confusion, and thank those who have given me a new understanding.

leemarrett

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#375654 2-Sep-2010 11:16

Awesome, thanks :)

It's funny though, even in this thread I'm seeing contradiction. But the general gist I'm seeing is that it will work, and work well, with my initial hardware set up.

Thanks!!!!