1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome to the new DBSTalk community platform. We have recently migrated to a community platform called Xenfono and hope you will find this change to your liking. There are some differences, but for the most part, if you just post and read, that will all be the same. If you have questions, please post them in the Forum Support area. Thanks!

Distance of triple LNB to 18x20 Dish?

Discussion in 'DIRECTV Installation/MDU Discussion' started by beachlover, Apr 16, 2010.

Thread Status:
Not open for further replies.
  1. beachlover

    beachlover Mentor

    30
    0
    Feb 27, 2010
    I'm making trying to use a dish that doesn't have the proper arm, can anyone give me some measurements as to where the triple lnb should be in relation to the dish? Maybe the measurement from the plastic middle lnb to the center of dish? to the bottom of dish? and to the top of the dish? With those three measurements I should be able to make it work.
     
  2. boba

    boba Hall Of Fame

    5,580
    0
    May 23, 2003
    Good luck you need the focal point of the dish you are using, not the dimensions of the phase 3 dish.
     
  3. beachlover

    beachlover Mentor

    30
    0
    Feb 27, 2010
    I thought that's what i'm asking for.... in laymans terms?
     
  4. carl6

    carl6 Moderator DBSTalk Club

    12,390
    906
    Nov 15, 2005
    Seattle, WA
    In laymans terms, the size and shape of the dish determines the distance the LNB needs to be from the reflector. Unless the dish you are trying to use is the exact size and shape of the 3 LNB dish, the focal point won't be the same.

    So any measurement of any other dish is going to be irrelevant.
     
  5. beachlover

    beachlover Mentor

    30
    0
    Feb 27, 2010
    That's why I wrote 18x20 dish in title.....so it's the same, but the arm is not....
     
  6. curt8403

    curt8403 Hall Of Fame

    4,481
    0
    Dec 27, 2007
    So, you are saying you have an 18 X 20 dish, but the arm is broken, or missing, or maybe a different mounting device (Like from a different dish)

    why not just order a dish upgrade from directv?
     
  7. beachlover

    beachlover Mentor

    30
    0
    Feb 27, 2010
    I have my reasons but will not discuss them here
     
  8. litzdog911

    litzdog911 DIRECTV A-Team DBSTalk Club

    12,171
    56
    Jun 23, 2004
    Mill Creek, WA
    We can't really help you if won't disclose your "reasons". What you're trying to do is just about impossible. The dish geometry and LNB type & positions must be closely matched for proper reception of multiple satellites with one dish. And with the newer mix of Ka-band and Ku-band satellites, it just about impossible to combine multiple dish/LNBs together anymore.
     
  9. curt8403

    curt8403 Hall Of Fame

    4,481
    0
    Dec 27, 2007
    remember, spraying your dish with PAM will result in rather buggy reception.
     
  10. Floyd

    Floyd Legend

    146
    2
    Nov 9, 2004
    Jeesh folks, it's a fairly simple question, with a fairly simple answer.

    from top front edge of dish to middle of middle lnb = 18"
    from center of top two bolts to middle of middle lnb = 13-1/4"
    from front of lower edge to middle of middle lnb = 12"
    Dish is 18" H x 20-1/2" W
     
  11. beachlover

    beachlover Mentor

    30
    0
    Feb 27, 2010
    you have restored my faith in humanity Thankyou
     
  12. JJJBBB

    JJJBBB Godfather

    270
    0
    May 26, 2007
    Kinda tough getting that out wasn't it? Why didn't anyone else just help him? Sorry dude wish I saw this thread sooner.
     
  13. boba

    boba Hall Of Fame

    5,580
    0
    May 23, 2003
    Nobody helped him, he was just given useless information.:nono2:
     
  14. joe diamond

    joe diamond Hall Of Fame

    3,071
    0
    Feb 28, 2007
    Beachlover,

    It is not as simple as you think. That dish is a parabolic reflector...like the inside of a spotlight. You need the formula for the inside curve of the dish. Then you have to find the focal point of that dish. Outside dimensions alone will not give you this.

    What you want to do is possible but beyond the skills of most. After you have the dish correctly pointed (az, el & tilt) at the satellite 23,000 miles out you have to correctly position the LNB to intercept the signal at the focal point of the dish.

    It is easier to acquire a dish outside the Directv or DISH system. Retailers like Solid Signal will have what you want and ship the same day.

    Report success.

    Joe
     
  15. Floyd

    Floyd Legend

    146
    2
    Nov 9, 2004
    There seems to be a reading comprehension failure here.
     
  16. cartrivision

    cartrivision Hall Of Fame

    3,862
    0
    Jul 25, 2007
    There sure does. At least the OP finally got the information that he needed (from you Floyd).... now he just needs to ignore all the people who are trying to "help" him by giving out bad information based on their misunderstanding of what he needed.
     
  17. Rosco

    Rosco AllStar

    65
    0
    May 27, 2007
    Don't know if this is what you are wanting to do or just fabricating one from scratch, but I've done one of these phase III dishes with the newer SL3 lnb, as the post say, better signal when you grind off the rib on the bottom of the lnb and re-drill the lnb mounting holes in the arm.
    http://www.dbstalk.com/showthread.php?t=139735&highlight=phase+III+dish
     
  18. JJJBBB

    JJJBBB Godfather

    270
    0
    May 26, 2007
    fgjkhj'; hklf'' ... !

    :D
     
Thread Status:
Not open for further replies.

Share This Page