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tomabill
Guest
is it possible to run to sky boxes off one dish without getting a 2 lead LNB?
yes but u would only be able to watch channels on both either as horizontal or vertical
the signals for channels r transmitted in horizontal and vertical
u can only watch 1 or the other
the signals for channels r transmitted in horizontal and vertical
u can only watch 1 or the other
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tomabill
Guest
so how does the double wire lnb work?
a new cable is run to the second reciever. if you wanted something like sky+ but only had one cable due to it being buried in a wall or whatever there is a system called a stacker/destacker made by a company called johansen that will put 2 lnb signals into one cable and split them at the bottom
but if you want 2 recievers (or even 2 channels most of the time) then a twin lnb will be needed
but if you want 2 recievers (or even 2 channels most of the time) then a twin lnb will be needed
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Flibble
Guest
tomabill said:
Technically it works by being effectively 2 totally separate LNBs in a single housing. Although if you're thinking of sharing a dish between 2 houses, you need to consider earth loops and the like because you might just end up with 240V between the inputs - which is not what you want when you adjust the dish at the top of a ladder....
Twins are less common these days though - quads (a 4 wire lnb) are much more common and the difference in cost is minimal (in some cases the quad is cheaper than the equivalent twin).
The only thing to look out for when looking at a 4-output LNB is to make sure that you don't get a quattro (4 fixed outputs) unless you're planning to use a multiswitch to distribute the outputs.
In the old days (!) you used to be able to just split the signal as on 19.2 E Sky used to mainly use V polarity. Then more channels started to use H, and then followed Lo and Hi bands.
You could still do it now, but the channels will be restricted by what polarity and band is selected on the lnb by the primary receiver. If you don't use a passive splitter, which blocks the power on one port, remember to switch off the voltage in the lnb settings for the second receiver.
If you only want to use the same cable because you can't be bothered to make the holes bigger in you wall, etc, see if you can get some shotgun cable (in pairs like speaker wire). The cable is much thinner and tends to pass through the normal hole. You just have to use f-connectors with smaller bore ends.
You could still do it now, but the channels will be restricted by what polarity and band is selected on the lnb by the primary receiver. If you don't use a passive splitter, which blocks the power on one port, remember to switch off the voltage in the lnb settings for the second receiver.
If you only want to use the same cable because you can't be bothered to make the holes bigger in you wall, etc, see if you can get some shotgun cable (in pairs like speaker wire). The cable is much thinner and tends to pass through the normal hole. You just have to use f-connectors with smaller bore ends.
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Flibble
Guest
Of course you can't do that if you have a long run because the losses in the thinner cable are higher.
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Flibble
Guest
It can happen if the two properties are on two different phases of the 3 phase supply that the electricity company delivers. If there's a fault in either receiver it can easily make one of the conductors of the LNB cable live, and if it's the outer shield, that 'live' could also be present at the rear of the second receiver..... nice surprise for the neighbours eh ?
You only need to do this if you're supplying two properties - not two rooms in a single property (unless you have a multiphase supply of course - you'll know - you have two or three electricity meters)
You can get doobries to protect yourself against it - an earth bonding strip (he suddenly remembers) - is what you're looking for - effectively it's a pass through F-connector to F-connector on a strip of metal that you earth (example by attaching to a cold water pipe, or an earth rod) - an example part is Labgear PSC050 - remember it needs to be protected from the rain (eg. in a suitable tupperware-type box)
You only need to do this if you're supplying two properties - not two rooms in a single property (unless you have a multiphase supply of course - you'll know - you have two or three electricity meters)
You can get doobries to protect yourself against it - an earth bonding strip (he suddenly remembers) - is what you're looking for - effectively it's a pass through F-connector to F-connector on a strip of metal that you earth (example by attaching to a cold water pipe, or an earth rod) - an example part is Labgear PSC050 - remember it needs to be protected from the rain (eg. in a suitable tupperware-type box)
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Flibble
Guest
Get the earth bonding thing - for a tenner (or less) you're totally safe.
Ease of telling if you're on the same phase ? Well normally in the UK houses are wired sequentially up a street to the red, blue and yellow phases - but that rule doesn't always hold..... the only sure fire way to find out is to cause a phase fault on your local distribution network and see whose lights go out
And yes it applies to any multioutput LNB.
Ease of telling if you're on the same phase ? Well normally in the UK houses are wired sequentially up a street to the red, blue and yellow phases - but that rule doesn't always hold..... the only sure fire way to find out is to cause a phase fault on your local distribution network and see whose lights go out
And yes it applies to any multioutput LNB.
Flibble said:
Very true, but it is ok for reasonable runs. Also, just to clarify for others, when I said in pairs like speaker cable, I didn't mean thin like speaker cable but just in pairs. It was just a bad choice of words. The cable I'm referring to is not as thick as CT100, etc, but is thinner like RG58 but in pairs. The F-connectors for these are similar in appearance to the normal ones except the inner core for the sheath fitting is thinner.
Oh, and for isolation purposes, you used to be able to get a properly isolated faceplate with F-connectors, so that the terminals would be effectively isolated. They were designed for flats, etc, where a single dish was installed to serve multiple households.
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Flibble
Guest
The cable you're talking about is CT63 - horrible stuff as far as losses are concerned, but it does fit 2 feeds through a 10mm hole with ease.....
