Spittling question - sorry...

[Utopie]

Splitting question - sorry...

So my interest has been sparked with all this satellite stuff since getting sly installed.

I have been doing some reading and am picking things up all the time (am used to the cable scene).

One thing that I haven't quite figured out is can you split the incomming feed off into 2, ala as in the cable scene, and use a signal booster if required.

I keep reading about LNB's with multi outputs etc...

One more question also. If I were to do this and got myself a linux sat box, could I actually get channels and satellites on it that you can't on the sly box without going motorised ?

Many thanks...

 

[bert1]

the signal is not "split" as you describe it m8....it is duplicated....

LNB with multiple outlets (can be 2 ,4,even 8) -these are the number of boxes u can connect up to one dish with this lnb and and they will all have an independent signal -so up to 8 different chans can be viewed at same time-LOL.....of course if u have pvr (eg sky+) then u must divide the number by 2 because each sat pvr needs 2 independant feeds to utilise the second tuner in the box..

(there is a loop thru method where u can run a pvr with just one feed but the second tuner is compromised as it can only view channels in a range close to the frequency of the channel on the main tuner plus must be same hor or vert polarisation)


As for mult-lnb....imagine the above but with another LNB with multiple outlets just to the side of it....this allows the dish to be tricked into thinking its in another position without needing a motor.....the cable coming from both the lnbs is connected outside near the dish to something called a disec switch situated close to the dish (eg-mast) .A cable feed is then run from the disec switch to your receiver. Your receiver will then let you choose between the 2 sats but u only have one cable....thered be a mass of cables otherwise....

I have 4 lnbs on my dish allowing 4 different sats to be viewed without using a motor...

 

[Utopie]

Nice one mate, thanks very much for the info...

Do you know why the feed cannot be split though, when cable and terrestrial/freeview can ? Would just be interestnig to know.

 

[bert1]

Im not an expert on the techy side m8 .....thats best coming from pinkhelmets & digidude -gained a lot of knowledge from them....but i think its something to do with how a sat system utilises the coax cable.......the system i have is capable of receiving around 4000+ channels
and that is far too big to be coming down the cable all at one time....the sat box only utilises part of the coax when ur watching a channel but has a full range to select from....when u split
i think u then loose the full range of choice and so you are compromised as to choice/range...
eg-some channels only available in 1 room and others only available in another...

Because of that I don't see why ud want to split it m8....Just plug in another feed to the LNB

 

[Moriens]

I'm not an expert either btw m80.
I think it's all to do with how the LNB on your dish works.
There are four settings for the LNB - vertical polarization or horizontal polarization and high band or low band. The receiver tells the LNB which to use when you select the channel you wish to view.

Lets assume that you split the feed from your LNB and connect each feed into seperate receivers and then do a bit of channel surfing on each of them:

If the channels chosen are both on the same polarization and band, then the two receivers can show one each. But if they aren't, then one of them won't work, and worse still, your LNB will have two receivers trying to control it and could ultimately foook it.

Might not be 100% accurate, but hopefully you get the idea.

 

[digidude]

yep as stated the satellite signal is split into four bands, vertical low, vertical high, horizontal low and horizontal high. voltage and frequency switches in the LNB are told what band to send down the cable at the request of the reciever for vertical 13v is sent to the LNB, for horizontal 18v is sent. for a high band a 22khz tone is also sent to the LNB

splitting the cable could result in 18v from one reciever being forced into the tuner of a 2nd reciever (not good), at best the 2nd reciever would be 'missing' three quarters of the channels its meant to recieve as itd be unable to control the switching of the LNB

 

[Utopie]

Right, got ya... I think... Check out the primary school analogy.

With cable and terrestrial, the signal passes straight through to your receiver and isn't conditioned by anything (bar the 'green boxes' and in terrestrials case, arial masts, both of which serve to carry and boost the signal on its travels, moslty).

But with satallite, the dish is the ariel, but the very first thing to condition the signal before it hits the reciever box is this LNB device, dictated to by the reciever box. Therefore, if there is more than one satallite receiving box on the single main feed, the LNB gets commands from 2 boxes which results in conflictions.

Pretend your talking to a ten year old


What are the chances of my standard sly dish having a dual LNB? slim to non? OK, how about replacing that LNB with a dual or even a 3 way LNB? Would sly really mind me doing this... is it even a plausable option.

Cheers guys.

BTW, I think this should be a sticky for satallite 101, I have found it really usefull. I find that if I grasp the real, real simple basics then its much easier to build upon. Noticed there seems to be an increase in the scene recently also...

 

[pinkhelmets]

We already have very good stickies covering how satellite tv works m8, but they are in the euro-sat-chat rooms. In any case anything too technical on the deeper workings wont be much use imho, people wont read it. So far this thread has nothing to do with 'Linux' receivers either so its not in the right place, it may get moved elsewhere. Maybe it should be in the sky section as you are trying to work out how to connect two receivers on a sky dish?

As for changing an lnb on your sky dish thats fine, you can get a twin or a quad or octo output, but you cant get 3-way (triples) because they arent made.

Anyway, take a read of stickies in this section to leran more about satellite tv- http://www.digitalworldz.co.uk/forums/forumdisplay.php?f=132

Hope that helps.

 

[digidude]

heres a link for an ebay search for quad LNBs m8 (4 outputs)

http://search.ebay.co.uk/quad-lnb_W0QQcatrefZC6QQfromZR10QQfsooZ1QQfsopZ1QQftrtZ1QQsacatZQ2d1

this is where i get mine from for work, i think most come direct from the back of sky vans tbh lol, but have a look through, i normally get them for about £8.50-£10 delivered, the best deal i had was 6 for £40 delivered so look at the last page first.

to replace on a sky dish a plastic pin is holding the old one in place, remove this and the whole unit slides straight out, slide the new unit in and connect the cable. connect your new cable for the 2nd reciever and slide down the weather proof cover and youre done