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Wiring from 3LNB dish for HDTV

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Anonymous
June 1, 2004 2:29:12 PM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

Can someone put me straight here. I'm totally baffled by the whole
LNB/multi-switch thing.

I'm wiring my house with coax outputs in every room, and want to have
HDTV capablilities. Looking at dishes like the Terk S25
(http://www.crutchfield.com/S-jnhser5qKta/cgi-bin/ProdVi...)
it has 3 LNBs with a multi-switch providing 4 outputs. It claims to
simplify wiring this way. I don't get it - what is the multi-switch
doing? Why is this simplified wiring, if now I need 4 coaxs outside
my house, instead of 3?

Can anyone point me to a website that explains all this mess?

More about : wiring 3lnb dish hdtv

June 1, 2004 10:13:47 PM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

"stankley" <pstankley@hotmail.com> wrote in message
news:728c4cea.0406010929.6dc9c87d@posting.google.com...
> Can someone put me straight here. I'm totally baffled by the whole
> LNB/multi-switch thing.
>
> I'm wiring my house with coax outputs in every room, and want to have
> HDTV capablilities. Looking at dishes like the Terk S25
>
(http://www.crutchfield.com/S-jnhser5qKta/cgi-bin/ProdVi...
&g=11500&id=essential_info&i=209TRKS25)
> it has 3 LNBs with a multi-switch providing 4 outputs. It claims to
> simplify wiring this way. I don't get it - what is the multi-switch
> doing? Why is this simplified wiring, if now I need 4 coaxs outside
> my house, instead of 3?
>
> Can anyone point me to a website that explains all this mess?

Each LNB picks up signals from a specific satellite orbital position. With
DirecTV the 101 degree position has all 32 transponders which get the
transmissionss from ground transmitters and send them out to the receivers.
The 119 position has transponders numbered 22-32 and the 110 position has
numbers 28, 30 and 32 which are converted by a special LNB to the
frequencies of numbers 8, 10, and 12. The receiver's request channels by
sending a signal regarding which LNB and transponder they need to use. The
multiswitch routes the recivers requests to the proper LNB and again routes
the signals from the requested LNB to the proper receiver. 3 LNB dishes now
have built in multiswitches that can handle up to 4 receivers. External
multiswitches can be added that handle up to 16 receivers though 8 is more
common. External multiswitches for 3 LNB dishes require 4 connections from
the dish and may have a 5th for an antenna or analog cableTV input. Thus a
5x8 (5 in 8 out) or a 4x4 are examples of multiswitches for a 3 LNB dish
while a 2x or 3x is only able to "see" one satellite position. A 3LNB dish
with an added external multiswitch requires a cascadable model that outputs
a 22 KHz tone from its Sat B inputs.

Pat

DrDon has written the following at AVSForum.com

Polarization is used to double the number of transponders on a satellite.
You can have two different transponders sharing the same frequency by
polarizing the signal. Your STB works like this: You tune a DirecTV channel.
Your box knows what transponder that channel is on. If it's on transponder
one, your STB sends out 13v which tells the LNB to select the LH (left-hand)
polarization and, hence, the odd numbered transponders. The LNB sends ALL of
the odd-numbered transponders down to the STB which then tunes out all but
transponder one. It then passes that digital stream on to the digital
processor, which extracts the information necessary for the channel you
selected.

Now, if you then select a DirecTV channel that's on transponder 8, your STB
will send out 18v, telling the LNB to select the RH (right-hand)
polarization and, hence, the even numberd transponders. You know the rest.

In a multi-satellite situation, you have a new problem in that the STB must
be able to request the correct polarization, but the correct satellite.
Transponder one on the 101 is the same frequency as Transponder one on the
119. So, obviously, you can't have send both sets of signals down the pipe
at the same time... they'd interfere with each other. So, they devised a
switch that uses an audio trigger. When you select a DirecTV channel from
the 119 bird, your STB sends out the proper voltage for odd or even
transponders ..PLUS, it sends a 22khz audio tone The switch hears the tone
and switches from one satellite's LNB to the other. The switch passes the
voltage to the appropriate LNB which does the rest.

A "multiswitch" Works like a telephone operator. The input lines to the
multiswitch send a constant voltage to each of the 4 LNBs (2 for 101 and 2
for 119.. remember, they're DUAL LNBs) and receives back the transponders
associated with that voltage. The multiswitch then senses what the STB wants
(by looking at the voltage and tone combination) and connects the STB to the
proper line. The line going from the multiswitch to the STB never has more
than one half of the transponders from either satellite on it at any given
time.

The Sat-C arrangement uses a special trick to take some transponders off of
the 110 bird and place them into unused slots on the 119. (The slots aren't
really unused. Dish transmits programming on them). Since the original
transponders on 110 are different from the slots on 119, a special LNB is
required that will shift the frequencies to the slots. Then, a special
combiner is used that strips out three of the Dish transponders from 119 and
inserts the DirecTV transponders from 110 in their place.
Anonymous
June 2, 2004 12:20:37 AM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

stankley wrote:
>
> Can someone put me straight here. I'm totally baffled by the whole
> LNB/multi-switch thing.
>
> I'm wiring my house with coax outputs in every room, and want to have
> HDTV capablilities. Looking at dishes like the Terk S25

If you are "wiring yer house", then get it WIRED to the hilt!

And I mean a MINIMUM of five cable outlets per room, several phone and
router outlets, as well as "future" conduits that will also handle the
newfangled optical as well to get piped into, that go from here to there
to via a central junction box.

"HDTV" needs NOTHING but a clean signal path!
Related resources
Anonymous
June 2, 2004 8:56:43 AM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

AH#49 <AH#49@your.net> wrote in message news:<40BCE5CE.CD954ED0@your.net>...
> stankley wrote:
> >
> > Can someone put me straight here. I'm totally baffled by the whole
> > LNB/multi-switch thing.
> >
> > I'm wiring my house with coax outputs in every room, and want to have
> > HDTV capablilities. Looking at dishes like the Terk S25
>
> If you are "wiring yer house", then get it WIRED to the hilt!
>
> And I mean a MINIMUM of five cable outlets per room, several phone and
> router outlets, as well as "future" conduits that will also handle the
> newfangled optical as well to get piped into, that go from here to there
> to via a central junction box.
>
> "HDTV" needs NOTHING but a clean signal path

I agree with you that now's the time to slam in all the wires I'm ever
going to need, but 5 cable outlets per room? Why so? Aren't 2
sufficient (e.g. for Tivo receiver boxes).
Anonymous
June 2, 2004 9:00:22 AM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

"Greywolf" <greywolfin45@*spamisbad*sbcglobal.net> wrote in message news:<vH3vc.4531$n65.3072@newssvr33.news.prodigy.com>...

>
> Each LNB picks up signals from a specific satellite orbital position. With
> DirecTV the 101 degree position has all 32 transponders which get the
> transmissionss from ground transmitters and send them out to the receivers.
> The 119 position has transponders numbered 22-32 and the 110 position has
> numbers 28, 30 and 32 which are converted by a special LNB to the
> frequencies of numbers 8, 10, and 12. The receiver's request channels by
> sending a signal regarding which LNB and transponder they need to use. The
> multiswitch routes the recivers requests to the proper LNB and again routes
> the signals from the requested LNB to the proper receiver. 3 LNB dishes now
> have built in multiswitches that can handle up to 4 receivers. External
> multiswitches can be added that handle up to 16 receivers though 8 is more
> common. External multiswitches for 3 LNB dishes require 4 connections from
> the dish and may have a 5th for an antenna or analog cableTV input. Thus a
> 5x8 (5 in 8 out) or a 4x4 are examples of multiswitches for a 3 LNB dish
> while a 2x or 3x is only able to "see" one satellite position. A 3LNB dish
> with an added external multiswitch requires a cascadable model that outputs
> a 22 KHz tone from its Sat B inputs.
>
> Pat
>

Thanks Pat - I think I get it. The multiswitch is routing the control
signal from the receiver to the appropriate LNB. I really appreciate
your explanation.
Anonymous
June 2, 2004 6:57:35 PM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

stankley wrote:
>
> AH#49 <AH#49@your.net> wrote in message news:<40BCE5CE.CD954ED0@your.net>...
> > stankley wrote:
> > >
> > > Can someone put me straight here. I'm totally baffled by the whole
> > > LNB/multi-switch thing.
> > >
> > > I'm wiring my house with coax outputs in every room, and want to have
> > > HDTV capablilities. Looking at dishes like the Terk S25
> >
> > If you are "wiring yer house", then get it WIRED to the hilt!
> >
> > And I mean a MINIMUM of five cable outlets per room, several phone and
> > router outlets, as well as "future" conduits that will also handle the
> > newfangled optical as well to get piped into, that go from here to there
> > to via a central junction box.
> >
> > "HDTV" needs NOTHING but a clean signal path
>
> I agree with you that now's the time to slam in all the wires I'm ever
> going to need, but 5 cable outlets per room? Why so? Aren't 2
> sufficient (e.g. for Tivo receiver boxes).

Well, it can allow you route signals from one room to another so that
extra receivers or other gizmos don't have to be purchased.
I had just four outlets and wished I had more, as we have six sat
dishes cable, and surveillance cameras.
Anonymous
June 7, 2004 6:37:17 AM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

>Each LNB picks up signals from a specific satellite orbital position. With
>DirecTV

Can I use a Direct TV 3 LNB with a Dishnetwork receiver?

Wayne
Anonymous
June 7, 2004 5:28:21 PM

Archived from groups: alt.tv.tech.hdtv,alt.satellite.tv (More info?)

Wayne Morrow wrote:
>
> >Each LNB picks up signals from a specific satellite orbital position. With
> >DirecTV
>
> Can I use a Direct TV 3 LNB with a Dishnetwork receiver?

I'm not positive, but I don't believe so.
I think they have different switching.
!