5 LNB and rain fade

Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by jamesbobo, Aug 29, 2007.

  1. jamesbobo

    jamesbobo with a grain of salt

    Jun 18, 2000


    I currently have a 3 LNB dish. At best conditions it's at 98% on two of the satellites, the third is 90%. It has to rain really hard to lose the signal on the two 98% satellites, moderatelly hard on the third. Snow has never been a problem no matter how hard or deep.
    With 5 satellites to aim at, how does it perform in the rain? The Slimline dish, since that is the one I would get if I ever upgrade.
  2. Marino13

    Marino13 New Member

    Jan 16, 2007

    I find the slimline performs better!
  3. Jon J

    Jon J Curmudgeon TCF Club

    Aug 23, 2000
    Music City USA
    It may be named Slimline, but the capture area looks to be much larger than previous dishes. So, shouldn't the performance be at least as good if not better?
  4. TyroneShoes

    TyroneShoes HD evangelist

    Sep 6, 2004
    Other than strength of the signal itself, atmospheric vagarities, and attenuation of the signal after the LNB, reception strength depends on three things, 1) aiming, 2) how strong the amp in the LNB is, 3) how large the reflector is and how well it is designed.

    1) Aiming can be trickier with the 5-LNB, but just as accurate. It depends upon the motivation and skill of the installer.

    2) The amplification is probably designed so that the final output of the dish is equal to or greater than previous models. This is a factor that they have a lot of control over, and it would be problematic for them if they didn't do it this way

    3) The reflector size is important, but when designers veer away from a parabolic dish (one focal point) to a parabolic-spherical dish (multiple focal points) some tradeoff in signal level is inevitable. The focal points defocus a little bit. Of course all current dishes are already parabolic-spherical, but there may be more tradeoff in one with 5 focal points. Its important to reflect enough signal to the LNB for the level to be within the window of operation for the LNB's amp, so there is a minimum size that will work. Also there is an acceptance factor. At some point the customer (wife) says "no way" to a larger dish.

    Bottom line, the SlimLine will probably perform at least equally to the 3-phase.
  5. JimSpence

    JimSpence Just hangin'

    Sep 19, 2001
    Binghamton, NY


    You do realize that how hard it is raining has little to do with rain fade. It's the density of the thunderclouds between you and the sats that has the largest affect. Typically, in my area, I know a storm is approaching up to 10 minutes before the rains start. And when the rain starts, my signal has returned. Those on the west coast may see the rains before they lose signal.
  6. mgoddard1

    mgoddard1 New Member

    Jun 2, 2004
    I still get rain fade if a big thunderstorm goes through but I don't think it is as susceptible to it as the 3lnb due to the larger dish size.
  7. HiDefGator

    HiDefGator New Member

    Oct 12, 2004
    My impression as well. My slimline seems to have less rain fade than the old 3 lnb it replaced. May depend on what sat you are watching. The slimline is defintiely aimed better though.
  8. Mark Lopez

    Mark Lopez Just click ignore

    Jan 1, 2000
    Hondo TX
    FWIW, I have the AT-9 dish and I rarely if ever get rain fade anymore as compared to the 3 LNB dish.

    As far as aligning, IMO it's easier because it has actual adjustment screws instead of having to just turn it by hand and then tighten it down. Not sure how the newer slimline works.
  9. newsposter

    newsposter Poster of News

    Aug 18, 2002
    SE PA
    and i know if there is lightning anywhere in 100 miles because my dsl goes out :)
  10. JimSpence

    JimSpence Just hangin'

    Sep 19, 2001
    Binghamton, NY
    Never had my DSL go out due to llightning. :)
  11. Mike Lang

    Mike Lang Administrator Staff Member Administrator TCF Club

    Nov 17, 1999
    My 3lnb was just swapped for a SlimLine. I can tell you that I'm getting much higher signal percentages with this than any installer (3 tried) could get with the 3lnb. Rain fade testing is yet to come.
  12. Todd

    Todd Gee thanks Jeremy...

    Oct 7, 1999
    I've gotten significant rain fade with both of them! :(
  13. henryld

    henryld New Member

    Aug 15, 2005
    Friendswood, Tx
    Ditto but I have not yet fine tuned my just installed 5LNB dish. Was going to do it yesterday but it rained darn near all day and I did have some rain fade.

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