Satellite feeds from dish, likely set up?

[foxhole]

Inherited a Sat dish and currently there are feeds to 4-5 points in the bungalow, two cables from dish but each internal point has only a single connection, what should I look for in loft by way of distribution set up ? Have freesat in lounge with two inputs, currently using just one,can I split existing for both inputs or does it need a second feed.

 

[Lucid]

Ordinary sat tuners need a direct feed - one cable per tuner - from the LNB to the TV or receiver. An 8 output (octo) LNB is the answer.

The standard LNB signal can't be successfully distributed if you want to have multiple receiver connected at the same time. The reason is that it's not a wideband signal. A TV aerial signal is, and under normal circumstances one signal can be split or split and amplified for several TVs. LNB signals work differently.

If we start with a single output LNB, you have some power from the satellite tuner to run the circuits in the LNB. These convert the signals beamed down from the geostationary satellite. The frequency of those signals is in the Gigahertz range. Part of the reason that the signals need converting is due to cabling. The higher the frequency signal then the more difficult (more expensive) it is to put it down a piece of coax and end up with something usable at the other end. The cables either have to be very thick or very short; or both! These things are impractical.

The LNB then is a signal convertor, and changes signals in the Gigahertz range down to Megahertz frequencies (950-1750MHz).

The second reason that makes standard LNB signals difficult to distribute is that the LNB is directed between one of four receiving states by the satellite tuner. The voltage from the tuner to the LNB can be 13 or 18V, so we have a high or low status. There's then a tone which is used to toggle between two polarities. That gives us 4 states. The tuner sets the LNB state depending on which group the channel you want to watch sits in; Low +ve, Low -ve, High +ve, High -ve.

If you split the single LNB signal between two or more tuners, then it's inevitable that at some point one tuner will need a low voltage state channel, but it will be overruled by the High voltage call from another tuner. A standard single LNB can be in two different states, so one tuner gets no signal.

A dual (twin) output LNB, or a quad, or an octo is really 2, 4 or 8 individual LNBs in a single 'box'. It divides up the incoming signal between 2 / 4 / 8 receivers within the LNB housing, so if you go for an octo then you need to be sure that the dish signal is strong enough to support it. A bigger dish provides a stronger signal where a standard dish might struggle to support a larger LNB.

There are amps which will distribute two LNB feeds, (see the Labgear LDU604 in another thread here, and also the 608 which is an 8 output version), but it's on the proviso that you understand that having more than one twin or two signal sat receivers connected at the same time will cause reception problems. Something else to bear in mind is that the output voltage from the satellite receiver tuners is never really off, even in standby, so just switching off one receiver to use another might not give the results expected.

If you want a system where any or all TVs can receive Freesat or Freeview then we need to have a chat about quattro LNBs and multi-switches.

 

[RepairingDave]

Have you checked to see if the internal connection points are connected to anything?

It sounds like the two cables from the dish/LNB both go to your lounge.

As @Lucid said, it is one cable per tuner - usually one tuner to watch and one tuner to record.

 

[foxhole]

Have you checked to see if the internal connection points are connected to anything?

It sounds like the two cables from the dish/LNB both go to your lounge.

As @Lucid said, it is one cable per tuner - usually one tuner to watch and one tuner to record.

The access points all have a single cable so not sure what the previous owner has done, only have two receivers and don’t need to record so may be lucky if bedroom access point is using the other line from the dish.
Not a problem if only able to use lounge sat receiver, just trying to understand what previous owner might have done.
Just to add to mystery there is a feed in the lounge of our annex( built at bottom of garden) With no visible signs of an external cable back to house.No sign of a second dish there either and tree cover would prevent signal is there was one.Luckily can receive Freeview with basic indoor aerial in all locations.

 

[Lucid]

Where you have a single cable, but the wall socket has three connections (usually #1 TV, #2 FM/DAB, #3 SAT) then the box in the loft or elsewhere is a signal combiner, and the wall plates are signal splitters.

One cable can carry all three signals because they operate in non-overlapping separate frequency ranges. Think of it like railway carriages on a track. One carriage for combined FM and DAB radio, another for the terrestrial TV range, and then one for a single satellite LNB feed.

One 'track' (one cable) allows the train to arrive at the station where the passengers and goods of the various carriages separate and go to their own destinations.

The loftbox has a feed for a combined FM/DAB signal, and one for the terrestrial aerial, and one for the satellite LNB.

On more sophisticated boxes there are two sat feeds. Alternatively, that 2nd LNB feed can be connected directly to the cable which goes to bedroom. This means no radio or Freeview TV, but if all that's required is a single sat feed for a TV then its not a problem.

 

[foxhole]

Tried bedroom feed but seems dead Sat reported no signal.Haven’t found any junction box in loft but probably under 500mm of insulation.No wall plates ,cable just sticking out of wall.

 

[RepairingDave]

.... just trying to understand what previous owner might have done.

It is sounding like they put in a load of cables for satellite feeds and they were never connected or they never upgraded the LNB to have the number of outputs required.

If you haven't got any standard TV sockets, (I think) you could use the existing satellite cable to connect either a loft aerial or external aerial provided that you can find the other end.

Do the two cables from dish run externally of internally?

 

[foxhole]

Dish on exterior wall , cables go straight eaves .

 

[RepairingDave]

If both the lounge connections provide a signal, the it could be only those two connected.
Other than that it is testing every access point and following the cables around the loft.

 

[foxhole]

If both the lounge connections provide a signal, the it could be only those two connected.
Other than that it is testing every access point and following the cables around the loft.

Only single connection in lounge .thanks

 

[ericmark]

The LNB (bit on the dish) needs power, and it seems the voltage supplied decides if the LNB receives vertical or horizontal signals, my LNB is seems is a hybrid, two outputs special for SkyQ and four for other satellite receivers. I know one of the receivers has output to daisy chain them, but the second box will only get either vertical or horizontal signals not both, which ever the first box is tuned to.

My TV only ever seems to pick up half of the programs, seems to either tune to vertical or horizontal not both. And the boxes it seems to depend on their age, some will not pick up all programs, and the electronic program guide only works A1 with the SkyQ the other boxes are all a bit hit and miss.

What we are unaware of is how much comes from satellite and how much from internet and SkyQ connects to both, it was the same with my ICECRYPT box, with terrestrial and satellite, it picked up both, and one was never sure which one was watching. Darn pain watching ITV3 +1 when if selected terrestrial it would turn off in the middle of a program at a set time, think it was midnight, but satellite continued playing.

Where I live now terrestrial has no commercial programs, so freeview is useless, so simply not bothered with it.