skew

[dunnsept]

(saying this like ricky from I love lucy) can somebody splain to me skew?

;-)

I would have assumed that skew was a function of the sat, not the TP. but just moved the dish over to G10R, which I had peaked for RTN, OK.. so I get a really strong and nice "scrambled or bad" message there with a Q of about 65% on the pansat.. so I figured I'd check what's on the other channels. no love at all. Q of like 8%.
RTN and Retrojams have the skew set at -45 for the highest Q, but that gets all of the others at like maybe 10%.
If I set the skew to -20, then all of the other channels are up to about 30% and RTN and retrojams are down to 15%
I guess I was wrong about skew being sat based..
anybody have any reasoning for this?
I wanted to switch skew control over to the pansat, but apparently it's not working. shut everything down, moved the wires to the pansat, I can run skew from -90 up to 90 and the Q doesn't change a bit.. put the wires back over to the 4dtv and it works fine.. just that I would like to have that finer control over it.
thanks!
Paul...

 

[Lak7]

Here is how I think of skew:
Skew is the difference from Your Lat to the Sats Lat.
Just like lining up to a Sat with elevation, you have to compensate for the angle you are looking at the Sat, unless it's due south.

 

[dunnsept]

right.. so it should be a function of the sat.. but for those TPs on that sat, 2 of them get the highest Q with skew at -45 while all the others are happiest at -20. just doesnt add up.
BUT.. I know how to fix it! MORE DISHES!!!!!

 

[Lak7]

Are you aware that RTN moved?
Can you list the TPs?
Remember, there are Horizontal and Vertical TPs.
So if you have 11720 Vertical at -45, then you should get 11805 Horizontal at +45.
You should not have to adjust the skew for each and every Sat. You should be able to put the Dish on your True South Sat, set the Skew for Horz and Vert, and use those numbers for all the Sats. When the Dish moves, it takes care of the Skew. You may need to "tweak" the skew for a few weak TPs here and there, but not for every TP.
There is 1 exception, AMC1's Ku Skew is "off" compared to the rest of the Sats.

 

[turbosat]

What size / type dish? Sounds like it may not be aimed right at the satellite. Set the skew at whatever is correct for your location, and try tweaking the elevation of the dish.

 

[Mr Tony]

skew is a function of your location versus the sats location

so the sat at your true south has a zero skew whereas the sats on the end of your arc have a bigger skew. Each persons skew is different because each persons true south is different

 

[dunnsept]

I know about the move.. I wanted to see what was on the others.. and all of those I'm looking at are vertical. That's the old equity stuff, (I think) I only used RTN and retrojams for reference.
everything else is fine. same setup I've been using (uh. for not long at all)
9' mesh, chaparral corotor, norsat Ku LNB.
I know I'm on the right sat.
11800V and I think 26000 (rounding)
with skew at -20 I get 30% on this TP
but on retrojams, I'm getting 8%.
if I set skew to -45, retrojams will go to 35% and the others on 11800 will drop to 10%
doesn't make sense does it...
wifey is watching something over on 4dtv.. when she goes to bed, I'll switch back over and get the details for the TPs etc..

 

[skewed]

Its the same for me here, I have some RTNs good and others are 0. I have narrowed it down to a problem that happens at both ehds of the arc. I once parked it on 123 and just for the heck of it manually skewed the dish for a perfect signal, but then I was off in the middle of the arc and on the east. I then just found a happy medium with the intent on fixing the problem another day. Thats the fun of it, trying to get it perfect. Also I am no expert at all but others have told me ku on BUD is a real pain.

 

[dunnsept]

yea.. doesn't make sense.. it's the fun part, but it's also a PITA in that it's SO hard to get these signals.
but, for continuity:
right now I'm on 11800V26657 skew -20 and I've got 30%
if I go to say 12103V2222 I get 8%
if I bump the skew over to -45, I get that one at 30%

I wonder if there's something wrong with either my feedhorn or LNB.. I only have a few Ku band sats setup currently so can't really tell... OR maybe 12103 needs to have the freq or symbol rate tweaked.
either way.. go figure.. it's probably also my system in general. not stable and not repeatable (actuator is not accurate enough)
time for a new dish!

just looked again.. somethings just fubar in the pansat.. it "thinks" one of those is horizontal when it's actually vertical. If I switch to H, then I get no signal at all. I might delete everything and re-scan.
sorry for the goofy post then, eh what.. need to research more before I post I guess

 

[stogie5150]

IMO you two guys have an aiming problem, or in the case of the BUD, a feed centering problem, not a skew problem. if your skew is set correctly at your True south satellite, it will absolutely be correct as your motor moves across the arc. With the exception of AMC 1, that is.

If your mast/pole is not perfect, and your motor mount isn't perfect,and your feed centering isn't perfect (on the BUD), your reception won't be either. I have had ALL kinds of problems with aiming issues, and I have never had my skew prove to have been wrong, if its set up correctly, especially on a motorized ku dish. I've had bent poles, whacked out motor brackets, bent u-bolts, my dish installs have been a mishmash of problems in the past.

But when you get it right...its SWEEEEET.

Stay at it. :up

 

[turbosat]

Beginning to sound like the man's figured it out--ku on Some buds is a pain. Could be that his 9' just istn't the best on ku, buds are complicated sometimes. You have the focal distance to set correctly, make sure the feedhorn is centered exactly for peak performance, declination has to be correct, east/west tracking also, etc etc. Hope he runs across an old primestar and puts it up for ku-it'll make his eyes roll with surprise at the signal strength!