2 sky boxes with a communcal dish



Hi Folks,

Just moved into my new flat and have had sky fitted. Everythings working fine in living room one.

Have an unconnectred cable in cupboard which pipes sky to living room 2 instead of livingroom 1, so have placed a splitter in between so the signal is going to both rooms. I'm assuming that since i have to do this i have one sattelite feed or LNB swithced into my flat.

WIth this configuration why when i turn one sky box on does the other go off?
I've been advised I need to have 2LNB's? I take it for some reason i cant split the signal? If this is the case then why not? What is the signals format?

Is their any soloution to my problem based on the fact one dish serves the whole 48 flats and the chances of me getting a second LNB are zero?



Chris Muriel

Well-known Member
Nobody can answer this without knowing the system diagram as communal aerial systems vary in their configuration.

You don't say what type of splitter you are using.
Both digiboxes may be trying to send 18 volts DC out of their LNB ports. You can actually turn them off in the LNB section of the "hidden" installer setup menu - Services 4 0 1 Select.
You can get splitters that include a a DC blocking capacitor on 1 or both ports. ; this too might help.

Chris Muriel, Manchester.


Ok then, lets assume I have one sat signal coming into my flat and want to split it to be watched on two TV's via two decoders.

Is this possible? If it's not why not?

I basically dont understand why i need two sat signals? All a splitter does is half the power signal and split two too paths, so providing the power level is sufficient each decoder should work?

Unless of course the decoders send signals back down the transmission line?


Ahh gotcha now! i'll try turning one of the LNB's off. Why do they send the 18volt signal down?

Fred Smith

Well-known Member
In non communal systems, satellite receivers actually send 13 or 18V DC to the LNB to power it and to switch polarity. They also send a 22Khz tone to switch from Low to High band. Contact your landlord or his aerial contractor to see if you can get a seperate mini dish fitted with quad LNB, then you can feed your two receivers independently and watch / record different channels at the same time.
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