Why do we need ku high/low band switching?

vism

Prominent Member
Joined
Feb 7, 2011
Messages
3,011
Reaction score
1,177
Points
574
Location
Royal Leamington Spa
To get all the channels in the KU band, we need voltage switching to tell the LNB to use high or low.

I was just wondering why is it not possible to have an ultra wideband LNB/tuner that could cover the whole band without switching?

It would allow any number of tuners from just 2 cables (one for each polarity). I'd really like to see a 6 tuner Sky box.

Any thoughts?
 
Cable loss increases with frequency so it would mean more expensive cable in the early days and is a standard now.
 
To get all the channels in the KU band, we need voltage switching to tell the LNB to use high or low.

Wrong, the voltage switching switches polarity. Tone switching is used to switch bands.

A 6 tuner Sky box, Ugh.
 
Last edited by a moderator:
To get all the channels in the KU band, we need voltage switching to tell the LNB to use high or low.

I was just wondering why is it not possible to have an ultra wideband LNB/tuner that could cover the whole band without switching?

It would allow any number of tuners from just 2 cables (one for each polarity). I'd really like to see a 6 tuner Sky box.

Any thoughts?

Strictly speaking voltage switching 12/18V is used to switch polarisation not frequency band, a 22Khz tone is used to switch to high band. So even if the cable was capable of handling the higher frequencies you still need to be able to select horizontal/vertical polarisation.
 
OK, tone switching, my mistake, question still applies tho.

Not worried about H/V as I have 2 cables.

Are you saying that it would need new cables to carry the extra bandwidth or are modern ones up to the job?

Is there any technical reason why you couldn't have an ultra wideband tuner/LNB?
 
OK, tone switching, my mistake, question still applies tho.

Not worried about H/V as I have 2 cables.

Are you saying that it would need new cables to carry the extra bandwidth or are modern ones up to the job?

Is there any technical reason why you couldn't have an ultra wideband tuner/LNB?

These sort of frequencies are used on cables when stacker/destacker systems are used. So it could be done. Wideband tuners and LNB's could also be done. However to prevent problems all the engineering tolerances would need to be tightened, no more cheap cables, saddle and clamp wall plates, or even twist on F connectors.

The current system has been standardised for many years now and the only advantage in changing it is the reduction of cables in SMATV systems. Domestic systems will still need one cable per tuner due to H/V switching.
 
Copper cabling has limits to the frequency bandwidth that it can carry and would require top quality cabling, connectors and fitting. There is a far easier solution already available although at present more expensive - optical fibre lnbs and optical fibre which at present is capable of feeding 64 tuners down one cable (and even multiple satellites, also some installers have achieved 128). This only requires two cables to the lnb, one for power and an optical fibre for output, converters are available for the receiver end to convert signals back to standard RF cabling for those receivers without optical lnb inputs.
 
Now that does sound interesting, never heard of fibre connections before...cheers
 
Do you mean that you haven't heard of fibre optic cables:confused:, or that you haven't heard of them for this purpose?
 
lol, the latter fortunately.
 
:)
 
Mmmmm, nice
 

The latest video from AVForums

Is 4K Blu-ray Worth It?
Subscribe to our YouTube channel
Back
Top Bottom