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SWM Power Inserters

Discussion in 'DIRECTV Installation/MDU Discussion' started by ArnoldJG, Nov 2, 2009.

  1. ArnoldJG

    ArnoldJG New Member

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    Jan 3, 2006
    When using a Sonora PS6242000 to power one SWM8, is there a minimum length of RG6 cable required between the Sonora PI and the Legacy3 port of the SWM? If powering one SWM8 with the PI28 to the SWM1 port, why is it recommended that the PI28 have 15 feet of RG6 between it and the SWM1 port?
     
  2. carl6

    carl6 Moderator Staff Member DBSTalk Club

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    Nov 15, 2005
    Seattle, WA
    To your first question, I don't know.

    To your second question, it has to do with proper impedence matching of the signal (as opposed to the power itself).
     
  3. Grentz

    Grentz New Member

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    Jan 10, 2007
    I dont know for sure, but I would use the same minimum as they recommend with the SWM PI. As Carl said it has to do with impedance matching.
     
  4. PokerJoker

    PokerJoker Godfather

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    Apr 12, 2008
    Las Vegas
    This is not a cut-and-dried situation.

    If you want to use less cable, try it and see if it works. Chances are, it will.

    I can state that I have one SWM-8 switch powered by a PI-21 (not 28) power inserter (not recommended) running through about a one foot cable (also not recommended) to the SWM1 input. It works, perfectly. OK, yes, I did pick the PI-21 over the PI-28 because I knew it would be so close that DC voltage drop would not be a problem (and because I happened to have one handy!). But I still think the RF matching issues are a bit overblown.

    As usual, just my opinion, YMMV, etc. etc.

    Keith
     
  5. ArnoldJG

    ArnoldJG New Member

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    Jan 3, 2006
    Can a PI28 or PI29 be connected to the Legacy3 port, and why might one wish to do this, as opposed to using the SWM1 port?
     
  6. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Since there is an AGC on the SWiM output, there are other factors you may not be aware of.
    If it works for you... great, but if the AGC starts acting up, you're screwed and may not know why.
     
  7. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Dec 9, 2006
    The SWM8 was designed for MDU racks. The Legacy3 powering works with the supplies they use.
    The SWM 1 powering is so the SWM8 could be mounted outdoors and the PI inside [since it's not weatherproof].
     
  8. ArnoldJG

    ArnoldJG New Member

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    Jan 3, 2006
    I have a Sonora PS6242000, which the manufacturer advises can be used to power up to six SWMs through thew Legacy3 port with a DC splitter. I was told that the unit can be used to power one SWM through the Legacy3 port without the DC splitter. I was also told yesterday by a Directv technician at the Denver technical center that there does not need to be any minimum RG6 distance between the PI28 or PI29 and the SWM1port. From your various comments, which I appreciate, it would appear that I will just have to try each solution, and see if each works. What is AGC?
     
  9. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Automatic Gain Control.
    The SWM8 controls the output to -30 dBm. [think of this like a volume control where the sound stays the same level all the time] If the signal is stronger, it will be limited and if it's weaker it will be boosted [within the limits of the SWM8].
    The DirecTV "technician" in Denver, might want to check with DirecTV engineering, since "he/she doesn't know what they're talking about".
     

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