[mythtvnz] Re: Best type of splitter for Sky + MythTV DVB-S

[Steven Ellis]

Hadley Rich wrote:
> On Mon, 05 Feb 2007 18:11:44 Daniel Williams wrote:
>   
>> This is purely based on my experience from getting things working for me
>> with the switch to D1, but its capable of tuning both H+V at the same time.
>>
>> I have both SKY + Myth working at the same time on the one LNB / Dish.
>>
>> My setup:
>> Sky Dish + Dual Head LNB
>> There is a splitter in the ceiling, which passes power on both ports.
>> This was installed by sky.
>> The mythbox wall outlet also has a splitter (this was a little future
>> proofing for when I get the next DVB card), one port which is power
>> pass, the others aren't.
>> DVB Card : Skystar2
>> Mythtv doesn't set any Disqec stuff, so it's just using the default 160E
>> Lnb of the dual head. The other head is set for 156E, and won't pick up
>> D1 AFAIK - it's there as a backup incase the sat that Sky uses dies like
>> B1 did last year.
>>
>> When TVNZ was on B1:
>>
>> Mythtv was not plugged into the power passing port, worked fine, Sky +
>> Myth co-existed nicely.
>>
>> When TVNZ moved to D1:
>>
>> Changed the polarity in Myth, mythtv still broken.
>> Unplug SKY the sky decoder, mythtv still broken
>> Changed mythtv to be plugged into the power pass port, Mythtv working
>> (stupid me LNB needs some power).
>>
>> Now, I was intrigued what would happen if I plugged the Sky decoder back
>> in, so I just did it (mentally thinking of the 'I have no idea how the
>> decoder broke' line to use to Sky if the decoder died).
>>
>> To my surprise everything works. I did a little tinkering to find what
>> combination worked for me, and only came up with one.
>>
>> In short -
>> If both Mythtv + Sky are sending power to the LNB, then everything works
>> fine.  There is a little flicker (<1sec) on sky reception when mythtv
>> tunes the DVB card, but it is perfectly watchable on Sky + Mythtv AT THE
>> SAME TIME.
>>     
>
> That's very interesting and a little odd. It sounds like I've got the same LNB 
> as you and the same all power pass splitter (from Sky) but I can't seem to 
> tune to horizontal without losing signal on the Sky box.
>
> If I issue `dvbtune -f 1733000 -s 22500 -p h -tone 0 -m` then the Sky box will 
> go to the rain fade screen instantly and then if I tune back to vertical with 
> `dvbtune -f 1921000 -s 22500 -p v -tone 0 -m` then it comes right again 
> instantly.
>
> May I ask what the settings are that you have in Myth for the DVB-S card (LNB 
> type, frequencies etc.)?
>   
Hi Hadley.

Interesting reading. Have a feeling that Dan's LNB is slightly offset to
allow for V + H in that the V signal is still visible enough when he is
on HPol.

Your behaviour is what i'd expect with a traditional Sky LNB.

So yours has a LOF of 10750 or 10650?

Steve

-- 
Steven Ellis - Technical Director
OpenMedia Limited
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