View Single Post
  #2   Report Post  
Posted to uk.d-i-y
[email protected] spuorgelgoog@gowanhill.com is offline
external usenet poster
 
Posts: 4,564
Default Sky Q and many channels at once - how does it work?

On Sunday, 16 February 2020 14:51:50 UTC, Commander Kinsey wrote:
How does Sky Q get several channels through one cable? When Sky HD came
out, we had to add a second cable to the dish to get two channels. But Q
does not need 6 cables to get 6 channels.


Universal LNBs work by the receiver selecting one quarter of the channels at any one time. It does this by alternating the voltage between 13V and 18V which will enable the LNB to switch between Horizontal and vertically polarised signals. A 22kHz tone then switches the LNB from a low and high band. Hence a quarter of the channels at any one time. Vertical Low, vertical high, horizontal low, horizontal high. It is for this reason a normal traditional splitter can't be used on your satellite dish as the box may be trying to request a channel on one quarter or the other box be requesting a channel on the other quarter.

The LNB output at Satellite intermediate frequency (IF) which sits just above the UHF band used for terrestrial TV and 4G internet signals and coax cable has a bandwidth for half the satellite signal (i.e. low band or high band).

The Sky Q system now uses a frequency band which now includes all the band previously reserved for traditional terrestrial TV signals. It is what we call a "wideband LNB" which ranges from 230Mhz just above DAB radio right the way through the terrestrial TV signal band and up to 2359Mhz just beneath the 2.4Ghz band typically used for WIFI. Because it is "nicking" space that it did not used to have it has a far greater bandwidth for all of its services so there is no longer the need for a high and low band.

The Sky Q LNB itself has two outputs which are not the same. One is a horizontal output and the other a vertical output.

Because the Sky Q system uses terrestrial space, it can't be diplexed with terrestrial tv on the same cable, it must have its own cables.

summarised from
https://www.smartaerials.co.uk/blog/...-universal-lnb

Owain