Use of a Unicable LNB on Duo2

[Heathy65]

I'm the proud owner of a shiny new Vu+ Duo2 with a pair of dual DVB-S2 tuners.

I've temporarily plumbed it into my ancient dish that was installed by Sky many-many years ago (it's been sat unused for years).

I only have a pair of coaxes from this dish (although I think it's got a quad-LNB on it, so 2 are currently un-cabled).

My requirement is for maximum recording flexibility (I'm only interested in the FreeSat services, nothing else). So I understand, in an ideal world, I would run 2 more cables therefore having each of my 4 tuners with their own dedicated connection from the quad-LNB.

Now whilst I could run two more cables it'd me a pain-to-do.... then I just happened upon the unicable LNB option, which TBH can't quite get my head around so I have a few questions:

Firstly does the Duo2 support unicable LNBs

Assuming it does will I be able to get as-good-as flexibility when compared to 4 separate cables (i.e. any transporter on any tuner with no cross-dependancies).

Cable-wise what would I need, will I need to use my 2 existing cables or will just one of them do.

Config-wise on the Duo2 what do I set so that the box 'knows' I'm using a unicable LNB. (I'm currently using VIX and have seen settings such as "loop through to" & "equal to" but don't fully understand those options).

Is the use of a unicable LNB specific to any particular firmware, i.e. will it would equally well with VIX, Blackhole or the native option.

Finally what are the disadvantages (if any) of using a unicable LNB when compared to a traditional quad-LNB.

Lots of question there I know, so thanks in advance for any responses.

[judge]

Not used one myself, but you can set one up after setting configuration mode to advanced.

30249

[afc_rich]

Nice set of questions there. Saves me typing them up as I was about to ask the same thing!

[TK4|2|1]

With a unicable or scr lnb you would only need 1 cable to feed your 4 inputs. Most unicable lnb's have 2 connections. 1 legacy (normal function) and 1 scr function. You could use both outputs. So legacy connection straight into the duo and configured as normal. With the scr connection just fit an IF splitter behind the duo and feed to the inputs, then it's just a matter of configuring it in the menu's. If done correctly you should have full independent access to all channels on each input.


Sent by pressing buttons.

[Heathy65]

With a unicable or scr lnb you would only need 1 cable to feed your 4 inputs. Most unicable lnb's have 2 connections. 1 legacy (normal function) and 1 scr function. You could use both outputs. So legacy connection straight into the duo and configured as normal. With the scr connection just fit an IF splitter behind the duo and feed to the inputs, then it's just a matter of configuring it in the menu's. If done correctly you should have full independent access to all channels on each input.

Thanks. So in relation to any disadvantages of a multi-LNB, is there a potential issue in that the IF splitter reduces the signal level on each of its outputs (in comparison to its input).

[TK4|2|1]

Thanks. So in relation to any disadvantages of a multi-LNB, is there a potential issue in that the IF splitter reduces the signal level on each of its outputs (in comparison to its input).

Yes any splitter will reduce signal. A 4 way will loose you approx 8db


Sent by pressing buttons.

[Rob van der Does]

Firstly does the Duo2 support unicable LNBs
Unicable support is in firmware, not in software. So it depends on the image used.
Having said that: AFAIK all DUO2-images have support for Unicable.



Assuming it does will I be able to get as-good-as flexibility when compared to 4 separate cables (i.e. any transporter on any tuner with no cross-dependancies).
Yes. No problems to be expected.
Make sure the tuners are set as:
- lowest frequency for the first tuner (seen from the LNB) the next frequency to the next tuner etc.


Cable-wise what would I need, will I need to use my 2 existing cables or will just one of them do.
Makes no real difference (and is depending on the number of physical connectors on the LNB
If the LNB has a legacy output, I would connect one cable to that (for spare/test purposes) and the other one to the Unicable output.



Config-wise on the Duo2 what do I set so that the box 'knows' I'm using a unicable LNB. (I'm currently using VIX and have seen settings such as "loop through to" & "equal to" but don't fully understand those options).

For the quad-DUO2 I would use one external splitter; then one cable to tuner A and one to tuner C. Set Tuner B to 'loopthrough to tuner A' and tuner D to 'loopthrough to tuner C'.


Finally what are the disadvantages (if any) of using a unicable LNB when compared to a traditional quad-LNB.
Not really.
OK: combining LNB's via a switch is difficult/expensive.

[Heathy65]

Thanks "TK4|2|1" & "Rob van der Does" for taking the time to answer, it's appreciated.

In relation to the loss imposed by the splitter do you think that would necessitate a larger dish.

FYI, I'm located in North Notts in the UK (DN10) and currently have a perforated mesh Sky installed dish (oval type).

[Rob van der Does]

Hard to say.
I would just give it a try and only replace when actually needed.

[TK4|2|1]

To be honest, It would be far easier and cheaper to install 2 extra cables from the 2 spare ports on your quad lnb. Scr Lnb's ain't cheap.