Diplexing can cause SWM systems to "burn out"??

Discussion in 'DIRECTV - SWMLine Discussion (private)' started by Alebob911, May 24, 2008.

  1. Alebob911

    Alebob911 Hall Of Fame

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    Hey all, Well like I said in a previous post, my neighbor switched to D* today because he confirmed the SWMline dish would be installed at his house. The installer said that diplexeing could cause the SWM setup to "burn out" and with this I ask you guys for your input and feedback. He said that it would disrupt the voltages and cause the "burn out". As with other Field testers I have successfully implemented diplexing in my setup without issues but I am curious if there have been any issues related to this or any information like this given to the installers during their training.

    One other note, the PI is 2 times smaller than the ones we were given and they are black. I will get a picture of it later this evening and post it.

    Oh yeah, my neighbor loves the PQ and channel choices and was glad to wait for the SWMline. That was the selling point! Good Job D*!
     
  2. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    If the diplexers pass DC, there is no reason for them to "burn out" the SWM.
    What could/can happen is that the diplexers attenuate [too much] the 2.3 MHz control signal.
    As I'm sure you known the SWM8 has a diplexer in it which would require a second diplexer to get the OTA out.
    Yes, the "final" PI for the SWMLine will be a smaller [lower voltage] PI.
     
  3. Alebob911

    Alebob911 Hall Of Fame

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    Thanks VOS. I had thought about the SWM8 and its diplexer so the installer kinda confused me a bit when he said it would cause problems.

     
  4. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Well it "could cause" problems, but not for the reason he gave.
    BTW: diplexing isn't recommended by DirecTV for the SWMLine.
     
  5. jwd45244

    jwd45244 Hall Of Fame

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    I have OTA diplexed down-stream of the PI and have had it that way since the first day I had the SWMLine installed (part of the first wave of the field trial).. While not officially recommended, it does work.
     
  6. Alebob911

    Alebob911 Hall Of Fame

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    What is the reason for the non recommended diplexing with the SWMline? I looked around here and couldn't find anything other than not recommended.
     
  7. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "best guess" is diplexers aren't really rated for passing the 2.3 MHz out the SAT port. DC, yes, but most [all] of the signals below 900 MHz are sent to the antenna port. This means what does get to the SWMLine is attenuated and going through two diplexers would drop the level even more. As always "some" diplexers may work fine, while others may not. Diplexers could be designed to work with SWMs, but none are yet and may never be.
     
  8. RobertE

    RobertE Active Member

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    Solid reasoning.

    They could also have something planned for that huge hole 5-900mhz. If not, why not just let OTA pass through unaltered? Makes one wonder...
     
  9. houskamp

    houskamp Active Member

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    From my experiance with SWM setups, I would say it's more along the lines that they don't want to be troubleshooting their sat connections with OTA to confuse it.. Can't blame them actualy..
    In my setup a local FM radio station will mess up the SWM signals.. I run several FM traps to filter out that interference... Mine has beeen running fine since the addition of the traps..
    Think the whole "no diplexing" thing is just a matter of simplicity for their install/repair departments..
     
  10. Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    I are mechanic.....:grin:

    There is a FM station a couple miles away and has been know to cause interference.

    I want to get rid of some of the extra wiring in the house and not having any idea what the trap is supposed to do, I don't know where it's supposed to go.

    You said you put several traps...how many would I need...what determines how many to use?

    MIke
     
  11. houskamp

    houskamp Active Member

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    That's the million dollar question.. in my case I put back in what I had found to work with my old sir360.. On the sir360 it took the one in my ant amp plus 2 more (placed before the ant line hits any sat lines.. I was originaly trying to get local channel 8-1 to be solid (was erractic) when playing with the traps.. Once I got the SWM I tried it without them and was having trouble "locking onto" the SWM, so I put them all back and it has been working fine ever since..
    This is why I can see why Directv doesn't want any involvement with diplexing OTA.. You can get a lot of weird problems that can take a long time to figuire out what is actualy causing them.. In my case I don't even know how much actual time I have invested in OTA :)
     
  12. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Something like this: http://www.solidsignal.com/cat_display.asp?main_cat=03&cat=Antenna FM Traps
    Radioshack has them too.
    It is "simply" a filter that "traps" the signal [doesn't let it pass], and sometimes if the signal is very strong, you add one another one or two [1+1+1...] to knock the signal down far enough.
     
  13. kevinwmsn

    kevinwmsn Hall Of Fame

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    I have OTA diplexed in my setup with some advice of people here in this forum. So far so good, one of my set the OTA signal is more consistant than with it being diplexed in than it was with separate runs(even on same cable).
     
  14. bwaldron

    bwaldron Impossible Dreamer

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    Sounds like a little attenuation did you good on that line.
     
  15. Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    Thanks for the answers.

    I'm still confused but less so now. :grin:

    I think I'll keep the antenna on a seperate line. Then I don't have to know anything. :lol:

    Mike
     
  16. jwd45244

    jwd45244 Hall Of Fame

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    If you diplex downstream of the PI, the you should be OK. I have had my set up that way since the first day I got my SWMLine
     
  17. houskamp

    houskamp Active Member

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    Yep.. thats what directv's line is too :)
     
  18. NR4P

    NR4P Dad

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    Any idea of what the lower voltage spec is?
    Would be nice to know in case ours die (like Smiddy's) and we ever need to replace it.
     

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