LNB with a sly dish

[satphil]

Hi

I am using a freesat box with my sly dish, is it possible to change the lnb to a 2,3,4 outlet lnb.

If possible any suggestions on best lnb to go with the dish or would it be better to go with a new dish as well.

I have a motorised system as well but don't want to use this

Appreciate any advice

Phil

[satwyn]

2 3 4 ?

[satphil]

Hi

:001_07:

Sorry for poor description, what i really want is can i change the lnb for an lnb that will have extra outlets/sockets to enable me to have upto 4 receivers in my house.

cheers

Phil

[Homer]

Hi Satphil,

Yes you can.

I have a 4 output standard Sly lnb on my Sly dish. I think there is even a Sly dish adapter to use standard 40mm collar lnb's.

I can use four receivers, or two double input receivers (Sly+ etc).

Sorted :-)

[RABBY]

satphil

I have a 4 output LNB On my Sky Dish ? They put it on when I upgraded to sky HD :cool:

P.s I put the Dish up>? LOL:302:

[satphil]

Hi

Thanks for replys. Is it a quad lnb that I need and if so are they easy to fit

Cheers

Phil

[simon 2003]

yes m8 slides on exactly same fitting as single lnb

you may or may not require the insert depending on size of your boom on dish most quads come with one

[AM556]

Just make sure it's a "quad" and not a "quatro", they may look the same but a quad has 4 equal outputs but the quatro has 4 different outputs (hi,lo,H & V...not what you're looking for).
Also best to go for one designed for the sly dish (wider than tall) rather than a conventional offset dish (taller than wide).

[Detlef]

I have an octo (8 output) LNB that is designed for Sly dishes.

But over here I have it on an 80cm dish.

Some of the Sly ones have a 40mm collar (the standard for LNBs) but they have lugs on the LNB which make them a bit non-standard. I'll dig out a Sly quad and photograph it tomorrow.

[Detlef]

Here is a Zinwell Quad. They normally come with a 40mm collar (shown) that fits directly onto a Sly minidish arm (Zone 1 or Zone 2).

Note the raised lug on the bottom (there is one on the other side as well). I have just filed them off to fit a standard 40mm collar on other makes of dish.

[maud]

Forgive me if I am wrong but I was always under the impression that owing to the shape of a sky dish that you needed a special LNB,

[echelon]

the zinwell and others will work on any dish , and will work on the sly dish they were designed for

I too have used them on sly dishes , as well as other quads off e bay , and have used these where you file the plastic lugs off for use in 40mm holders as well

so to answer post 1 , yes , just change the single sly lnb for a quad sly lnb , same as sly would do for sly plus

[AM556]

You do maud. However, you can fit either way round but you won't get peak performance as due to the different shape dish, you'll be picking up a degree of background noise from around the edges.

[Detlef]

Forgive me if I am wrong but I was always under the impression that owing to the shape of a sky dish that you needed a special LNB,

I have seen that posted in many places but have not found it to be the case.

I tested the horizontal ellipse theory by turning an LNB through 90degrees and changing the H to V on the receiver and it made no difference.

It would need a professional spectrüm ana1yser to prove it for certain but simple results seem to confirm that the acceptance angle of a Sly LNB is, for all intents and purposes, circular and easily accommodates a normal dish.

[Detlef]

Just to add. An LNB will not cut off at the edges of a dish but will need to be almost as sensitive at the edges. That means all LNBs will receive an amount of background noise.

[mrbleu500]

The main thing with a non standard sly lnb is to make sure you setup the skew correctly, needs to be around 15deg in southern UK, which looks odd compared to a typical sly install.

http://i275.photobucket.com/albums/jj300/mrbleu500/icecrypt_1_P1312014.jpg

Picture credit - Rolfw

[beansontoast]

I thought sky dishes were elliptical to make the alignment easier at installation? i.e. wider so the direction doesn't need to be exact.

[Detlef]

No.

The acceptance angle of a dish gets narrower as the dish gets bigger.

As the Sats are arranged around the equator (the so-called Clarke Belt) at approximately 3 degree intervals the dish width needs to be about 50cm wide to reject adjacent sats. The dish height is not so important as there are no Sats above and below the normal belt.

[AM556]

The dish height is not so important as there are no Sats above and below the normal belt.

I'm afraid the hight of the dish has NO bearing on the position of the satellite. The hight/width of the dish is predetermined by a shape called a parabola that can focus incoming signals to a central focal point (the LNB). An example of a full parabola would be a prime focus dish, whereas an offset dish utilises just one quadrant of a complete parabola, which explains why the dish seems to be focused on the horizontal plane when in fact it is receiving a signal from much higher.
Any part of the parabola of a prime focus can be used as a dish, be it 1m tall x 10cm wide, or 1m wide x 10cm tall as long as the LNB is designed specifically for that shape. With that in mind, an LNB made specifically for a given dish with be able to accept a negligable amount of background noise. However, the use of "universal" LNBs will lead to the acceptance of some background noise to a greater or lesser extent.

A good example of an offset V sly LNB is the Philips SX1019/SX1019s and here you can see the scalar rings of the feedhorn clearly show the eliptical shape needed for the sly offset dish.
http://i937.photobucket.com/albums/ad214/AM556AM556/philipsSX_LNBs.jpg

[Detlef]

I'm afraid the hight of the dish has NO bearing on the position of the satellite. The hight/width of the dish is predetermined by a shape called a parabola that can focus incoming signals to a central focal point (the LNB). . . . . .

My quote about the vertical dimension (height) of the dish refers only to its ability to reject adjacent Sats.

There are Sats either side of 28.xE (26E and 30.5E albeit weak in the UK) but none above or below it. Therefore the reduced vertical dimension of the dish has no effect on rejection.