Question about Freesat signals
 

So the next question then, is if some of the people have freesat and some
have pay once Sky boxes, can both coexist on the same dish and multiswitch?
Brian

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"R. Mark Clayton" wrote in message
...

"Peter Duncanson" wrote in message
...
On Sat, 22 Aug 2009 15:28:54 +0100, ChrisW
wrote:

I am confused about satellite TV signals. With DTT I feed the signal
from one aerial into a distribution amplifier and the signal and all
channels are then available to any of the amps distribution points. I
am told that for satellite one needs a separate LNB for each TV set -
dual and quad LNBs seem to be common. I was planning to feed a single
Freesat signal into the Sat input of a suitable distribution amp and
was expecting the Freesat signal to be available at all distribution
points and to be available wherever I had a suitable decoder.

In what way is my understanding wrong? Is it that only one channel at
a time is available on any one LNB? If this is the case, would that
same channel be available on any decoder in the setup? How can one
combine Freesat signals with DTT in a home distribution system?

Two tricks are used to maximise the bandwidth from the satellite two your
dish.

1. There are two bands of ~1GHz each. These are mixed down to a single
band between ~1GHz and 2Ghz (which is about the limit of what you can get
down a cable).

2. The signals are sent in horizontal and vertical polarity, without the
polarity the channels would overlap somewhat and you would get adjacent
channel inteference. Only one polarity can be sent down the wire at once.

Essentially the receiver tells the LNB which band and polarity it wants
(by volts and tones). In a multi-switch all four are sent from the dish
to the switch and the selection is made inside the switch.

Have a butcher's on Wiki.


The way to do it is with a Multiswitch fed by a Quattro LNB. Note
"quattro" not "quad".

Depends on your switch - the latest EMP Centauri can cope with either.

Emerging technology is going to use fibre to send the whole lot down a
single fibre.


A multiswitch can supply many separate feeds to individual decoders
(Freesat boxes)s.

For example I have a Triax TMPR 5 x 8 Multiswitch in my house. The 5
refers to 4 inputs from a quattro LNB and 1 input from a terrestrial
aerial. The 8 refers to the number of separate outputs. Each ouput is
distinct from the others. You can be watching or recording 8 different
things at once.
http://www.triax.co.uk/?alPage=&rkPage=&articleId={41D13EE6-2A3A-481C-8E5A-A8C3D37DA700}

I currently use 5 of the outputs - 2 each to 2 Freesat recorders and 1
to a non-recording Freesat box. I don't currently distribute the
terrestial TV signals through it, but this might change sometime.

--
Peter Duncanson
(in uk.tech.digital-tv)

Question about Freesat signals
 

Surely every time you attempt to share the focal point with more and more
lnbs, the performance of the system goes down. They cannot all be in the
best position, surely?
Brian

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Brian Gaff -
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"Bill Wright" wrote in message
...

"Steve Terry" wrote in message
...

Or for less cost you could put up 2 dishes, each with a quad LNB
to give you those 8 outputs
Or one dish with an octo LNB.


A multiswitch is only worth bothering if you want more outputs
or can't put up more than one dish
Yes, although there are now some multiswitches that need no local power
supply. They get all their power from the receivers.

Bill

Question about Freesat signals
 

Don't know of any that do justice to stereo sound though..
Brian

--
Brian Gaff -
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in the display name may be lost.
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"Tony" wrote in message
...
ChrisW wrote:
I am confused about satellite TV signals. With DTT I feed the signal
from one aerial into a distribution amplifier and the signal and all
channels are then available to any of the amps distribution points. I
am told that for satellite one needs a separate LNB for each TV set -
dual and quad LNBs seem to be common. I was planning to feed a single
Freesat signal into the Sat input of a suitable distribution amp and
was expecting the Freesat signal to be available at all distribution
points and to be available wherever I had a suitable decoder. In what
way is my understanding wrong? Is it that only one channel at
a time is available on any one LNB? If this is the case, would that
same channel be available on any decoder in the setup? How can one
combine Freesat signals with DTT in a home distribution system?

Satellite is a little different to terrestrial broadcast, the LNB is part
of the receiver and has a switching signal that selects the polarisation.
This is a way of packing the channel closer together without them
interfering. As you go up the frequency the channels are on alternating
polarities. So for 1 polarity selection you only get half the channels
available at a decent level on one LNB.

You can have 2 LNB systems (one for each polarity) and distribute those
around the house with 2 cables, but you then need a separate selector box
that switches 2 cables to each receiver, or each receiver needs to be able
to have 2 dish/LNB feeds and select internally.

I'm not sure what quad LNBs are for, no doubt someone else will answer.
Maybe for more signal, or different satellites or different bands.

You can't generally mix satellite and terrestrial raw signals on the same
cable, likely they would interfere. The alternative to multiple cables is
one sat receiver with an RF modulator and use a carefully chosen frequency
and put that on your terrestrial network. You then use some sort of
remote repeater to control the satellite box. The Sat signal then appears
as one analogue TV channel.

--
Tony

Supplementary question
 

At 10:44:48 Sun, 23 Aug 2009, Andy Burns
wrote:
On 23/08/09 10:37, John Legon wrote:
Can someone please explain the point of the "loop out" socket on my FTA
satellite receiver?

Allows another satellite receiver to be used (e.g. in a bedroom) so long
as the one with "loop out" is switched off.

Thanks for this. I assume that the first box (with the loop out) would
have to be on stand-by rather than switched off (from the mains), as
there might be some active circuitry to avoid signal loss or whatever,
and perhaps also to supply power to the LNB.

--
John Legon

Question about Freesat signals
 

"Petert" wrote in message
...
On Sat, 22 Aug 2009 18:05:53 +0100, "R. Mark Clayton"
Emerging technology is going to use fibre to send the whole lot down a
single fibre.

I think it's already emerged:

http://www.triax.co.uk/Products/Fibr...cal%20LNB.aspx

Apparently quite expensive at the moment


I did touch on this in my recent Wotsat column. Several manufacturers are
bringing equipment out, and the whole thing does look very promising.

Bill

Question about Freesat signals
 

"R. Mark Clayton" wrote in message
...
snip


Emerging technology is going to use fibre to send the whole lot down a
single fibre.

I think it's already emerged:

http://www.triax.co.uk/Products/Fibr...cal%20LNB.aspx

Well I would say it was still emerging.


Apparently quite expensive at the moment

Not half, but expect this to change and to be able to cascade the LNB's.

Actually, when you look at the global cost of a system, it isn't that bad.
Copper is expensive. I'm anticipating that soon we will be able to replace
very long (500m) CT233 cables with fibre.

Bill

Question about Freesat signals
 

"R. Mark Clayton" wrote in message
...

"Bill Wright" wrote in message
...

"Steve Terry" wrote in message
...

Or for less cost you could put up 2 dishes, each with a quad LNB
to give you those 8 outputs
Or one dish with an octo LNB.


A multiswitch is only worth bothering if you want more outputs
or can't put up more than one dish
Yes, although there are now some multiswitches that need no local power
supply. They get all their power from the receivers.

Bill


That is pushing - if only one receiver is on (or configured to provide LNB
power in standby) then you have to power the switch and any LNB in use
down one cable...

I quizzed several manufacturers about this at the recent CAI show, and they
assured me that a modern Sky box will be untroubled by the load. I am a bit
sceptical.

Bill

Question about Freesat signals
 

"Brian Gaff" wrote in message
om...
Surely every time you attempt to share the focal point with more and more
lnbs, the performance of the system goes down. They cannot all be in the
best position, surely?
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Bill Wright" wrote in message
...

"Steve Terry" wrote in message
...

Or for less cost you could put up 2 dishes, each with a quad LNB
to give you those 8 outputs
Or one dish with an octo LNB.


A multiswitch is only worth bothering if you want more outputs
or can't put up more than one dish
Yes, although there are now some multiswitches that need no local power
supply. They get all their power from the receivers.

Bill

Not with you Brian.

Bill

Question about Freesat signals
 

"Brian Gaff" wrote in message
m...
So the next question then, is if some of the people have freesat and some
have pay once Sky boxes, can both coexist on the same dish and
multiswitch?
Brian

Yes. This happens all the time.

Bill

Question about Freesat signals
 

In message , writes
On 23 Aug,
"Bill Wright" wrote:

I quizzed several manufacturers about this at the recent CAI show, and they
assured me that a modern Sky box will be untroubled by the load. I am a bit
sceptical.

How is it proposed that fibre fed LNBs are powered?

Line power using James Bond laser at the receiving end?
Alternatively, I would think coax would work.
--
Ian