what is difference between a Sky Q and quad universal LNB

June 5, 2017
by
Tom Smart

What’s the difference between a Sky Q and quad universal LNB?

 

Sky’s latest offering Sky Q. Never mind the fact that almost every aerial and satellite installer the length and breadth of the country hates it. (This is because it works completely different) I must say from a usability experience it is a good system. Multiple tuners so you can record more than the standard 2 channels that traditional Sky+ and Sky+HD. Multi-room is now wireless so no extra cables between your satellite dish and the second room are required. Which begs the question:

 

What is different with the new Sky Q LNB?

 

For the eagle eyed among you will notice that it only has two outputs which both need to be connected to the main Sky box. Whereas the traditional LNB’s used for Sky either have 4 or 8 outputs.

 

Let’s begin this with a brief explanation of the old Sky Quad and Octo LNBs.

 

Okay so the only different between single, Quads and Octo universal LNB’s are the fact the Octo just has more outputs for more TV’s, otherwise they are completely the same so I won’t make reference to this again.

 

I’m only giving a brief explanation here so I first recommend reading a previous blog first. https://www.smartaerials.co.uk/blog/why-cant-you-split-a-satellite-signal-cable

 

Universal LNB’s 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.

 

Satellite signals are beamed down from the satellites in space to the satellite dish at a frequency which is far too great to be contained by the coaxial cable. At this point the signals are oscillated to fall down to a frequency band – Satellite intermediate frequency (IF) which sits just above the UHF band used for terrestrial TV and 4G internet signals and has a bandwidth of around half of that which was previously available before being oscillated. So the universal LNB will oscillate one half of the frequency band at a great rate than the other half, hence the high and low band.

 

So that’s your brief on how the Quad LNB used to work for Sky and why each Sky box either needed two cables for a recordable or one for a non-recordable box.

 

How the wideband Sky Q LNB is different from the Quad Universal LNB

 

The Sky Q system now uses a frequency band which now includes all the band previously reserved for traditional terrestrial TV signals (It is this part mainly for installers where Sky Q has become a pain in the backside). 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 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. This alone will give box almost 5Ghz of bandwidth which is massive. These cables are then connected to your Sky Q box and any additional Sky multi-room boxes are installed with a wireless connection (not via the WIFI router) and the secondary box. Obviously WIFI can experience black spots on larger buildings so it is also possible to install the secondary Sky multi-room box with a data cable.

 

Because of all this no switching at the LNB is required at all it already has access to all of the channels. This makes it far simpler to add additional tuners and the Sky Q silver actually has 12 tuners! All with no extra cables installed.

 

I’m sure the enthusiasts among you will be thinking. Hang on a minute no switching, we can just split the signals now unlike changing the LNB and theoretically yes if you installed correctly set up diode protected splitters, although you would have to install two splitters no one for the horizontal and vertical bands but you could only ever connect another main Sky Q box – not something that is likely to be done at a single address.

 

Another major point to make is that with a Sky Q box can never be connected on ‘single feed mode’ as it would miss out on either the horizontal or vertical signals – half the channels! It is possible to connect a Sky Q with a single feed but it would need to be done via a dSCR amplifier (not cheap) and this is another blog, coming soon. 😊

 

Some problems you can run into when swapping the LNB over for a new Sky Q LNB

 

Obviously as the Sky Q is wideband and goes over the top of the TV frequency band so satellite diplexers of any kind can be used. These would need to removed from the system and separate independent cables installed.

 

Triplexed and Quadplexed wall plates can no longer be used with Sky Q. As the wall plate itself filters and separates the signals it will try to separate the terrestrial TV and satellite signals. We know now that this would try to send half of the Sky Q signals to the TV or aerial part of the wall plate.

 

It’s more difficult to share satellite dishes between dwellings. If have a quad or an Octo feeding two separate dwellings, you would need now to install separate satellite dishes. Although a Hybrid LNB in now on the market which can serve both Sky Q and universal LNB signals for Sky and Freesat.

 

Major alterations to communal TV systems now required. Again because of the interfering terrestrial TV signals. This is just an amplifier change for a dSCR multi-switch amplifier and then the connecting Sky Q box would need to be set up in dSCR mode. Seems simple but I have already had numerous issues with Sky not letting us install their Sky Q boxes, the Sky engineers not understanding this type of system and not being able to connect this boxes using this method and us the independents just becoming a middle man whom Sky will only half communicate with.

 

That’s it for this one. If you want to find out more about Sky Q and TV systems stay subscribed for ‘Sky Q and communal IRS systems’ where I will inform you of the changes required for blocks of flats and apartments.

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