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AU9-S Pre Installation LOS Prep work

Discussion in 'DIRECTV Installation/MDU Discussion' started by mhowle, Dec 5, 2008.

  1. Dec 5, 2008 #1 of 10
    mhowle

    mhowle New Member

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    Dec 1, 2008
    Hey Guys... GREAT Forum!
    I have a question that I can't seem to find the answer to and hope some of you will guide me in the right direction.

    I am prep'ing for D* to do a AU9-S install at my shop that is basically in the middle of a woods. It will be possible with the removal of a few trees.

    My question is:
    With a location of 37.0205 Lat / -88.8988 Lon the 101W sat is at 45.2/201.9. Can I just use a sighting compass and go east of 201.9 two or three degrees to get LOS on 99W and west 18 degrees to get LOS on 103, 110 and 119 then cut the trees that prevent LOS in that 20 degree sweep? I realize that the elevation will vary from 45.7 down to 36.7.

    Why I am confused:
    When I use my lat/lon to locate all five sats individually on dishpointer, I come up with a 27.1 degree sweep.

    Dishpointer data:
    99W - 45.7/198.3
    101W - 45.2/201.2
    103W - 44.6/204.2
    110W - 41.7/214.2
    119W - 36.7/225.4

    Do I cut the trees that prevent LOS using the individual sat coords from dishpointer (27 degrees) or like I mentioned above, the ones that fall in the 20 degree sweep.

    I just want to be prepared and not have the installer waste a trip due to LOS issues. It probably will not be that much difference between the two in labor. I just want to know which is correct.

    Thanks in advance,
    -mhowle
     
  2. Dec 5, 2008 #2 of 10
    clb4g9

    clb4g9 Legend

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    Sep 23, 2007
    The first thing I would do, if you're having LOS issues, is verify that you need the 110 and 119 sats. If you don't (most people don't but I'm not sure which do; someone else on this forum could tell you), I would buy the Slimline-3 LNB. It doesn't require the 110/119 sats, and will cut down your tree cutting. Same dish, different LNB; I got the dish w/one of these LNB's on ebay for $55.99 shipped--solidsignal has just the LNB for $30 plus shipping. Might save some trees....
     
  3. Dec 5, 2008 #3 of 10
    carl6

    carl6 Moderator Staff Member DBSTalk Club

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    Nov 15, 2005
    Seattle, WA
    I agree with the 3-LNB suggestion.

    As to the width of your window, the orbital slots cover about a 21 degree arc, at the orbital position. That does not mean your look angle will be (or only be) 21 degrees. Dishpointer is pretty good, I would have faith in what it is showing you.
     
  4. Dec 5, 2008 #4 of 10
    mhowle

    mhowle New Member

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    Dec 1, 2008
    Thanks for the reply clb.

    D* is going to supply the 5 LNB AU9 slimline dish, a WB68 and do the install.

    I just want to make sure I have line of sight to all sats before the install which is Monday between 8-12.

    There will not be that many trees that will need to be trimmed/cut, just the one's directly in front of the dish. I'm mainly confused about the 20 degrees vs 27.1 degree difference.


    Thanks again
    -mhowle
     
  5. Dec 5, 2008 #5 of 10
    mhowle

    mhowle New Member

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    Dec 1, 2008
    Thanks Carl6 but let me make sure I understand before I trim/cut a tree that is unnecessary.

    If I get the coords for each sat and point to it with a compass at the correct azimuth and elevation and there is a tree top in view a couple of degrees either way.... trim it?

    In other words... make sure I have a clear window from 198.3 to 225.4 (at the correct elevation).

    Sorry to be a pain... I just want to make sure I understand before I start trimming tomorrow.

    Thanks,
    -mhowle
     
  6. Dec 5, 2008 #6 of 10
    bobnielsen

    bobnielsen Éminence grise

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    Jun 29, 2006
    Bainbridge...
    The reason for the difference is that the angle between the satellites is greater when measured from surface of the earth than when measured from earth's center.
     
  7. Dec 5, 2008 #7 of 10
    carl6

    carl6 Moderator Staff Member DBSTalk Club

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    Nov 15, 2005
    Seattle, WA

    Unless you know what you are doing with that compass, you would be better off using dishpointer to determine which trees to trim. Also make sure (when using a compass) to compensate for magnetic declination if your azimuth is given in true. If you are experienced with a compass great, I've just seen too many people (in a map and compass course) who claim to know what they are doing head out several degrees off where they should be. I'd hate to see you cut trees that don't need trimming.
     
  8. Dec 5, 2008 #8 of 10
    Johnnie5000

    Johnnie5000 Godfather

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    Mar 26, 2008
    It's 20 degrees at the Equator, which is where the satellites happen to be orbiting. It's 27.1 where you're at. Couple thousand miles makes a difference. :D
     
  9. Dec 5, 2008 #9 of 10
    bobnielsen

    bobnielsen Éminence grise

    8,473
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    Jun 29, 2006
    Bainbridge...
    No, it is 20 degrees measured from the center of the earth. At the equator, the distance to the satellites is less than from the earth's center and angle will be larger. Away from the equator, the angle decreases. It also decreases as you get further away from the subsatellite longitude.
     
  10. mxyztplk

    mxyztplk Cool Member

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    Sep 28, 2007
    D* may install the LNB5 on that dish, even though you may only require an LNB3.

    You may wish to ascertain whether D* is installing the LNB5 for you because it is needed, or rather simply because, in your area, they have not as yet trained personnel on the LNB3, and/or do not have sufficient stock of the LNB3, and/or they randomly install LNB5's or LNB3's depending on what is available.

    Based on recent posts in other areas, this is more or less what is happening in areas where the LNB3 will suffice.

    Another way that you can determine if the LNB3 would suffice is to tell D* that you determined that you have fine line-of-site to the 99-101-103 birds, but not to 110 and 119, and ask them if they need to install the LNB5 (i.e., instead of the LNB3).

    Of course, if you are sure that you require the LNB5, this would not apply.
     

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