Guru - Dish Tilt/Skew fine tuning?

Discussion in 'DIRECTV Installation/MDU Discussion' started by shorton, Jan 19, 2017.

  1. shorton

    shorton New Member

    2
    0
    Jan 13, 2017
    >>Accidentally started in main DirecTV forum, moving to here.<<

    re fine tuning DirecTV new SWiM SL3 LNB and slimline dish

    I think I've got a handle on dialing in the Azimuth and Elevation, but the tilt adjustment for the dish is the most crude adjustment mechanically on the gimbal. With it's 3 carriage bolts and stamped steed loose-fit circular slotted holes, one can put the dish's tilt several degrees different while the degree pointer remains at the at the same place (just by taking up the slack in 2 directions).

    So since it's not a fine tune parameter in any docs I've seen, I gather this adjustment isn't that sensitive. I understand these LNB's use circular polarization so "skew" isn't an issue, but "tilt" is still important to coincide with the virtual line between the 3 sats.

    For an OCD engineer like myself, I'd like to adjust it best I can. I've got a tree that will eventually creep into the edges of my LOS, and the wife gets bent when the signal goes out due to storm, so I'd like to maximize it hoping to minimize signal loss, and get the best quality I can. My dish is easy enough to get to, I've got way more time to fiddle with it than an installer would, and I don't mind.

    Is there a good procedure to fine tune tilt? I don't mean the way to do it physically, I can wrestle the fine adjustment itself, I mean procedurally. As in "... go to this sat and adjust, then that one, etc...." Or is this so insensitive that it's a waste of time? Just set it using the dish's inaccurate tilt protractor and forget it.

    ??

    Thanks!
    Scott
     
  2. MIMaverick

    MIMaverick New Member

    20
    0
    Jan 17, 2017
    That fine tunings a critical part in any installation. Yes you any roughly peak any odu with the on screen signal meter but fine turning is going to garner better odds of weather storms without significant loss. Think of it terms of shooting a long range shot millimeters in your scope translate to quite a few inches... your satellites are 25 thousand + miles out, but without a meter I don't know how you would have any success in the dithering process
     
  3. P Smith

    P Smith Mr. FixAnything

    26,173
    539
    Jul 25, 2002
    W.Mdtrn Sea
    there is a help - use STB to tune
     
  4. jimmie57

    jimmie57 Hall Of Fame

    9,938
    820
    Jun 26, 2010
    Texas City, TX
    Before you start, take a magic marker or similar and put a line across the 2 axis' that you are going to work with so that you can have a point to move it back to if you get it out of whack and to see how little you moved it when you adjust it.

    Most people set the tilt to whatever the instructions in the receiver say to and then forget it. For the other 2 settings. I have used the Satellite Signal Strength screen and had a helper watch the screen.
    Concentrate on the 101 first.
    I move whatever direction I am working on until the reading goes down to basically 80. Then set the fine adjustment to zero. Now count the turns and even the last partial turn while you turn the screw in the opposite direction. Do this until your helper tells you that the reading has peaked and came back down to 80. Now go back half of the turns it took to do this.
    Repeat for the second axis.
    Now check the 99 and 103 signals. Most times this might require a tiny bit of elevation to get a stronger signal on these 2 but that is where all the HD channels are.
    I spent about an hour doing mine a few years ago.

    In 2012 an installer came to replace my LNB that had got knocked out by lightning. He did not like where the dish was and just left it and put up a whole new dish closer to the electric service. He had a meter and dialed in the aiming in a matter of about a minute or 2. His numbers were as good or better that the hour I spent doing it the time before.

    Good luck.
     
  5. shorton

    shorton New Member

    2
    0
    Jan 13, 2017
    I wasn't clear. Clarificaitons:

    1) I'm only concerned about dish tilt/skew. I know how to dither the other 2 adjustments (Azimuth and elevation).

    2) Assume I have elevation and azimuth dithered perfectly on the center sat, 101. Since 101 is the center sat I' think the dish tilt/skew should have relatively little effect on 101's signal (?) The dish would be rotating about the axis of that beam. If this were the only sat, and with circular polarization the tilt/skew would be unnecessary, like the old dishes. I expect that it is the 2 sats to each side (99,103) that will be the most affected by tilt/skew. Or not :) ?

    3) I think I'm going to be able to borrow a meter form an installer. If not I'll probably buy one. If there's a way w/o it (using STB), I'm curious to hear that as well, but not a big deal either way.

    4) I don't need any details on methods and mechanics to adjust the tilt/skew a little. I can handle those mechanics.

    What I'm looking for is the methodology for testing the best skew settings. Assuming the 4 things above, how do gurus dial in tilt/skew (if they bother). I never see it covered in anyones answers or the official install manuals for that matter.
     
  6. P Smith

    P Smith Mr. FixAnything

    26,173
    539
    Jul 25, 2002
    W.Mdtrn Sea
    nobody bother, it's already calculated for each ZIP code - you are wasting your and our time
     
  7. jimmie57

    jimmie57 Hall Of Fame

    9,938
    820
    Jun 26, 2010
    Texas City, TX
    Nobody ever messes with that.
    If you want to try it, do the method I described for the other 2 adjustments but use the 99 and 103 for signal strengths.
     
  8. inkahauts

    inkahauts Well-Known Member

    24,990
    1,551
    Nov 13, 2006
    Here's the thing if your pole is perfectly level there is no dithering to do with tilt. It's just going to be right. That's the theory anyway and I don't know if anyone who's ever been able to show different. I tired once when I was having issues with peaking signals and it was a total waste of time. (I had a bad reflector as it turned out)
     
  9. peds48

    peds48 Genius.

    20,073
    1,075
    Jan 10, 2008
    NY
    the is a reason why, tilt is the one thing you set and forget. There is nothing to adjust, just make sure your mast is leveled.




    Sent from my iPhone using Tapatalk
     
  10. peds48

    peds48 Genius.

    20,073
    1,075
    Jan 10, 2008
    NY
    Right on! Agreed all the way.....


    Sent from my iPhone using Tapatalk
     
  11. Jodean

    Jodean Icon

    843
    18
    Jul 17, 2010
    right, tilt can be off 4 degrees either way with very minimal effect on signal

    here its 86, but 90 or 82 still work fine and pass eiv
     
  12. GTS

    GTS Member

    273
    4
    Mar 4, 2007
    Get a SL5 (SWM or otherwise) LNB, tune skew monitoring the 110 sat to your heart's content. There's "Passing" then there's "Peaking".
    Don't know why some people insist on telling others what to do or not do with their time and money.
    It's your time and your money - tweak away and enjoy.
     
    Last edited: Jan 21, 2017
  13. P Smith

    P Smith Mr. FixAnything

    26,173
    539
    Jul 25, 2002
    W.Mdtrn Sea
    Duh ? - yeah, sure ! just avoid pulling hair from our heads :p
     
  14. RCinFLA

    RCinFLA Legend

    111
    1
    Oct 3, 2006
    I just replaced my old SL5 AU9 dish with Slimline with SL3 LNB since 110 is not used and 119 does not carry any channels in my area of S. Fla. I also decided to change the dish tilt angle to split the line between 99 and 103 sats instead of the original angle of SL5 which is tangent between 101 and 119. The three LNB feed port locations seem to only have horizontal offset between 99/101/103 along the long dimension of dish.

    Azimuth was dead-on to magnetic corrected heading but the elevation had to be set greater then calculated. Calculation for tilt is 66 degs (Directv uses 90 degrees for no tilt where dish long direction is horizonal to horizon). 66 degs should put the long dimension of dish along the satellite belt centered on 101. Original SL5 had tilt of 55 degs to align for 101 and 119. Elevation was suppose to be 51 degrees at my location but turned out to require closer to 60 degrees on new dish scale markings which would be higher then highest sat belt at due south longitude satellite at my location. Azum was 227.4 magnetic.

    The pole was adjusted to vertical within a couple tenths of degree so it is not the reason for elev discrepancy.

    Interestingly I checked the old AU9 dish setup by Directv tech and it was set to 33 degs elevation which is also way off 51 degs. I did not check the old pole vertical setting before I changed it out with new pole which is slightly longer to clear roof edge with wider Slimline dish.

    I assumed there is no difference in LNB mount location on dish and you could change out SL5 to SL3 LNB without effecting 101 position pointing direction. Maybe this is not true although I doubt it since it would require multiple versions of at least dish LNB mounting arm. If the LNB is at the correct focal location the dish tilt should not effect the elevation to 101 satellite.

    The LNB mounting arm and its attachment to dish is not super structurally solid, in my opinion. I would not recommend using it to push dish around during alignment. It would be relatively easy to bend it up or down slightly.
     
  15. peano

    peano Icon

    801
    33
    Feb 1, 2004
    I had to tweak the skew on my Phase III to get the best signal on 99 and 103. Took me a few hours of fiddling but now I get 80s on them. I must assume if it makes a difference on a smaller dish, it would make a difference on the approved dish. Mind you, that is probably why the not so "Slimline" is so big.
     

    Attached Files:

Share This Page

spam firewall