FTA skew, Direct TV not.

[prosat]

I see Direct TV dishes pointing to many satellites, like 60', 101', 110',119'. No matter where it points, the lnb always has 0 degress skew.

Why the FTA lnb has to skew if not pointing direct-south satellite?

Just curious.

 

[mastermesh]

that's the difference between circular and hv

H/V require skew... circular does not. My understanding is that Ku Band is H/V. DirectTv/DishNetwork/Bell Expressvu is Circular.

Circular is stronger I think?... but also more expensive to maintain?

That's why Direct TV dishes are 18" and Ku Dishes are bigger.

 

[Mr Tony]

circular skew is just that, circular. So it can be aimed anyway (sideways, caox down, upside down) and the skew still works. DBS satellites are more powerful so they need to be at least 9 degrees apart

Linear (H/V) is lower powered satellites (thats why we need a 30" or larger) and the reason it has to be skewed is due to where you are in the US. Your true south satellite is 0 skew because you're aimed right at it. But the farther away you get, the more you need to skew to get the optimum signal

 

[global0]

I see Direct TV dishes pointing to many satellites, like 60', 101', 110',119'. No matter where it points, the lnb always has 0 degress skew.

Why the FTA lnb has to skew if not pointing direct-south satellite?

Just curious.

Circular transmission works in the same way that Linear does. There is no difference. You probably have made your observation in a place where the requierd skew is minimal. Look at DN own recommendation for skew values and see how different they are for different locations of the country.
http://www.dishnetwork.com/content/products/installation/azimuth/index.shtml
so, for example, if you look at this zip code range 90000 - 99999 (CA and there abouts), you notice that they are asking for a few degrees. (It is 90-whatever value they have in the table).

 

[Mr Tony]

global
The reason for that above is because you have to aim at 2 satellites (which are at different areas of the clarke belt)

 

[global0]

global
The reason for that above is because you have to aim at 2 satellites (which are at different areas of the clarke belt)

True, I am sure once you need to point a single dish to two or maybe more sats, then you need to compromise and find the sweet spot that may not match for any of the sats and I was only discussing the basic principle for both approaches.

 

[PSB]

The only reason you have to skew DBS/circular satellite dish is to take into account the differing heights of the satellites in the sky

 

[global0]

The only reason you have to skew DBS/circular satellite dish is to take into account the differing heights of the satellites in the sky

So, let's simplify the problem so that we can discuss easily without the risk of confusion.
Assume that this is a single dish and one LNB.
So if one wants to have this dish setup in CA, MN and FL would it always have the same skew values? right now, I am thinking that these three locations would have different skew values, but I could be wrong.

 

[Mr Tony]

if you are aiming a single slot DBS dish (DirecTV, Dish 300), skew is irrelvant

If you are aiming a multisatellte dish (Dish500, Superdish, DirecTv phase III), you need to skew it as the dish elevations are differetn depending on where in the US you are

As an example, in MN 119 is at 32 degrees and 110 is at 37...so the dish has to be skewed to pick up both. When I aimed a single dish at 110, skew is up/down (no skew is involved)

 

[drhydro]

My single lnbf DTV dishs/lnb's dont even have a way to adjust skew.

 

[Mr Tony]

The Dish 300's/DirecTV dishes didn't have skew

 

[global0]

interesting, thanks!