Mailing List Archive: LNB power with dual DVB-S cards

LNB power with dual DVB-S cards

david.shepherd at attglobal

Jul 20, 2009, 10:08 PM

Post #1 of 9 (5424 views)

This had me stumped for a while so thought I'd record what I learned
today for anyone else who needs it.

I have 2 DVB-S cards in my backend. A Hauppauge Nova-S and a SkyStar
Technisat. I also had a Zinwell/DSE Freeview DVB-S box plugged directly
in to the TV. (I bought this when I cancelled Sky and before I got the
DVB-S cards sorted out)

I had the cable from the dish going into the Zinwell then from the
Zinwell to a single power-pass splitter to each DVB-S card. Everything
worked fine, multi-rec from both cards etc.

I just upgraded my telly to one with Freeview HD built in, so I no
longer needed the Zinwell/DSE Freeview DVB-S box. I also bought a all
power-pass splitter because I was pretty sure that the Zinwell was
powering the LNB.

So after lots of connecting and disconnecting from splitters, probing
with a multimeter and testing LiveTV, I discovered the following:

1) The Skystar Technisat card provides LNB power (~18V) all the time,
even when not recording.
2) The Hauppauge Nova-S card provides LNB power ONLY when recording.
3) When feeding both cards from a all power-pass splitter stops BOTH
cards from working (possibly overpowering the LNB?)
4) Using the single power-pass splitter works fine ONLY IF the Technisat
card is connected to the power pass side and the Nova-S card is
connected to the the no-power-pass side of the splitter.

So it all works fine again now.

Cheers
Dave

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Re: LNB power with dual DVB-S cards [ In reply to ]

steven at openmedia

Jul 21, 2009, 12:27 AM

Post #2 of 9 (5251 views)

On Tue, July 21, 2009 5:08 pm, David Shepherd wrote:
> This had me stumped for a while so thought I'd record what I learned
> today for anyone else who needs it.
>
> I have 2 DVB-S cards in my backend. A Hauppauge Nova-S and a SkyStar
> Technisat. I also had a Zinwell/DSE Freeview DVB-S box plugged directly
> in to the TV. (I bought this when I cancelled Sky and before I got the
> DVB-S cards sorted out)
>
> I had the cable from the dish going into the Zinwell then from the
> Zinwell to a single power-pass splitter to each DVB-S card. Everything
> worked fine, multi-rec from both cards etc.
>
> I just upgraded my telly to one with Freeview HD built in, so I no
> longer needed the Zinwell/DSE Freeview DVB-S box. I also bought a all
> power-pass splitter because I was pretty sure that the Zinwell was
> powering the LNB.
>
> So after lots of connecting and disconnecting from splitters, probing
> with a multimeter and testing LiveTV, I discovered the following:
>
> 1) The Skystar Technisat card provides LNB power (~18V) all the time,
> even when not recording.
> 2) The Hauppauge Nova-S card provides LNB power ONLY when recording.
> 3) When feeding both cards from a all power-pass splitter stops BOTH
> cards from working (possibly overpowering the LNB?)
> 4) Using the single power-pass splitter works fine ONLY IF the Technisat
> card is connected to the power pass side and the Nova-S card is
> connected to the the no-power-pass side of the splitter.
>
> So it all works fine again now.

I've seen similar issues before.

It looks like the Technisat puts out a lot of power and if you use an all
ports power pass with a Sky or Freeview STB there are similar problems.

One other solution is to use a seperate power injector to power the LNB.

Steve

--------------------------------------------
Steven Ellis - Technical Director
OpenMedia Limited - The Home of myPVR
email - steven@openmedia.co.nz
website - http://www.openmedia.co.nz

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Re: LNB power with dual DVB-S cards [ In reply to ]

stevehodge at gmail

Jul 21, 2009, 1:21 AM

Post #3 of 9 (5222 views)

On Tue, Jul 21, 2009 at 7:27 PM, Steven Ellis <steven@openmedia.co.nz>wrote:

> It looks like the Technisat puts out a lot of power and if you use an all
> ports power pass with a Sky or Freeview STB there are similar problems.
>

I think it's more accurate to say that you may have similar problems in that
situation. I've been running a SkyStar 2 (2.6D) and a Sky box through an
all-ports power pass filter for three and half years and I've never had any
problems with either.

Cheers,
Steve

Re: LNB power with dual DVB-S cards [ In reply to ]

steven at openmedia

Jul 21, 2009, 4:30 AM

Post #4 of 9 (5235 views)

On 21/07/2009, at 8:21 PM, Steve Hodge wrote:

> On Tue, Jul 21, 2009 at 7:27 PM, Steven Ellis
> <steven@openmedia.co.nz> wrote:
> It looks like the Technisat puts out a lot of power and if you use
> an all
> ports power pass with a Sky or Freeview STB there are similar
> problems.
>
> I think it's more accurate to say that you may have similar problems
> in that situation. I've been running a SkyStar 2 (2.6D) and a Sky
> box through an all-ports power pass filter for three and half years
> and I've never had any problems with either.
>
>

I've been using Skystar 2 cards with myPVR customers who have Sky
STBs. With every customer I've had to use a single port power pass
splitter or I have issues with the LNB.

Steve

Steven Ellis - Technical Director
OpenMedia Limited
email - steven@openmedia.co.nz
website - http://www.openmedia.co.nz

Re: LNB power with dual DVB-S cards [ In reply to ]

Jul 21, 2009, 4:39 AM

Post #5 of 9 (5228 views)

On Tue, 2009-07-21 at 23:30 +1200, Steven Ellis wrote:
> I've been using Skystar 2 cards with myPVR customers who have Sky
> STBs. With every customer I've had to use a single port power pass
> splitter or I have issues with the LNB.

I've got a box with two old Skystar 2 cards and a Sky box plugged into
an all ports power pass splitter. This has worked fine on a couple of
different Sky LNBs.

hads
--
http://nicegear.co.nz
New Zealand's Open Source Hardware Supplier

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Re: LNB power with dual DVB-S cards [ In reply to ]

steven at openmedia

Jul 21, 2009, 4:47 AM

Post #6 of 9 (5232 views)

On 21/07/2009, at 11:39 PM, Hadley Rich wrote:

> On Tue, 2009-07-21 at 23:30 +1200, Steven Ellis wrote:
>> I've been using Skystar 2 cards with myPVR customers who have Sky
>> STBs. With every customer I've had to use a single port power pass
>> splitter or I have issues with the LNB.
>
> I've got a box with two old Skystar 2 cards and a Sky box plugged into
> an all ports power pass splitter. This has worked fine on a couple of
> different Sky LNBs.
>

Now I'm wondering if it was a revision issue as all mine pretty much
where out of the same batch.

Hads - What revision where your units?

Steve

Steven Ellis - Technical Director
OpenMedia Limited
email - steven@openmedia.co.nz
website - http://www.openmedia.co.nz

Re: LNB power with dual DVB-S cards [ In reply to ]

Jul 21, 2009, 5:22 AM

Post #7 of 9 (5237 views)

On Tue, 2009-07-21 at 23:47 +1200, Steven Ellis wrote:
> Hads - What revision where your units?

I don't recall off hand, the version that came with a USB remote, 2.6d
does ring a bell.

hads
--
http://nicegear.co.nz
New Zealand's Open Source Hardware Supplier

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Re: LNB power with dual DVB-S cards [ In reply to ]

tortise at paradise

Aug 18, 2009, 4:06 AM

Post #8 of 9 (4775 views)

----- Original Message -----
From: "Steven Ellis" <steven@openmedia.co.nz>
To: "MythTV in NZ" <mythtvnz@lists.linuxnut.co.nz>
Sent: Tuesday, July 21, 2009 7:27 PM
Subject: Re: [mythtvnz] LNB power with dual DVB-S cards

One other solution is to use a seperate power injector to power the LNB.

>>>>>>

What voltage 12V? 14, 15 18? Does it matter?

Also is there a preferable LO frequency - is there any effective difference using a 11.30 or a 10.60 for Freeview.

Thanks in advance!

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Re: LNB power with dual DVB-S cards [ In reply to ]

dave2 at wetstring

Aug 18, 2009, 9:27 PM

Post #9 of 9 (4757 views)

On Tue, 2009-08-18 at 23:06 +1200, Tortise wrote:
> > One other solution is to use a seperate power injector to power the LNB.
>
> What voltage 12V? 14, 15 18? Does it matter?

Voltage does matter, it's one of the signals the LNB uses to choose
between inputs. For a Sky LNB, it should be fine with either 13 or 18,
since it doesn't use the voltage to switch between low and high LOF.

> Also is there a preferable LO frequency - is there any effective difference using a 11.30 or a 10.60 for Freeview.

Provided the LOF is whatever your LNB is doing, there's no difference.

--
David Zanetti <dave2@wetstring.net>
http://hairy.geek.nz/
Overzealous Sysadmin