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Barrel connectors

Discussion in 'DIRECTV Installation/MDU Discussion' started by TAK3210, Dec 17, 2011.

  1. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    This is merely a easy QC check.
    "Rated" to 3 GHz doesn't mean anything, other than the loss is known.
    For any of this to have any merit, the loss specs would be published.
     
  2. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "My fight" here is to educate and not to harass installers for following their rules.
     
  3. texasbrit

    texasbrit Well-Known Member

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    Agree with VOS here. Maybe I would go further, unless a barrel connector is actually faulty, it makes no difference what barrel connector you use.

    The signal losses in barrel connectors are so small as to be irrelevant. Max is typically about 0.6db, at DirecTv frequencies (and they top out at 2.2Ghz, not 3Ghz, by the way), and even the best will have an insertion loss of about 0.3db at 2.2GHz so swapping one out MIGHT gain you 0.3db per connector.
    FYI Perfectvision specs their HF barrel connectors at 0.1db but I have my doubts!

    As VOS says, this is more of a QC issue, like many of the installer "rules". Using cable "swept" to 3Ghz is another one, often discussed here.
     
  4. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Maybe even more of the issue is that it's very hard to measure losses this low.
    Amphenol, who you may know is a major connector manufacturer, doesn't mention insertion loss in any of their specs, and instead return loss, which for those that don't understand what it relates to is impedance and how close to [a "pure"] 75Ω the connector is.
     
  5. DarkLogix

    DarkLogix Godfather

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    And then antrox (a major connector manufacturer) even has a patent on what they call CAM port that has lower insertion loss via better contact
     
  6. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    need a link please as this make no sense in the RF world.
     
  7. DarkLogix

    DarkLogix Godfather

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  8. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    These get to the true "root" of the differences between connectors and the frequency "rating", but more their return loss specs.

    This type:
    [​IMG]
    Though used by Zinwell on the WB68 DirecTV "approved" multi-switch, has the worst impedance match, because of those "fingers". They're the equivalent of driving a nail through coax for impedance. :eek2:

    All of the F81 connectors are like what is shown on the right:
    [​IMG]
    The center conductor of the CamPort matches the dimensions of the coax MUCH closer and has a similar amount of dielectric to the shield, so the impedance is MUCH closer to 75Ω.
     

    Attached Files:

  9. P Smith

    P Smith Mr. FixAnything

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    Looks like the CamPort is better, but in a theory. Without independent tests and disclosing all results with real diagrams/screenshots it would be same marketing pitch.
    They are claim: Insertion Loss: 0.1 dB MAX.
    While for The New Eclipse Contact the measures are omitted.
     
  10. DarkLogix

    DarkLogix Godfather

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    Its looking like the eclipse is newer but not better even per them, so that leaves me wondering why, well better than having 2 flat sharp edges its still much less than the camport's full contact
     
  11. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    There is nothing "new" there.
    These types of "center pins" have been around for "god knows" how long.
     
  12. DarkLogix

    DarkLogix Godfather

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    whats claimed to be new in that patent is that the contacts are rounded
     
  13. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "Big deal"

    There is more marketing hype in all of this than anything else.
    "The best barrel" can be no better than about 1" of RG6.
    "The worst barrel" would be the same 1" of RG6, with a nail driven into it.

    Nobody can accurately measure 0.1 dB of insertion loss repeatably.
    Unless a barrel is damaged, I doubt they have 0.5 dB of loss, regardless of which type.
    What would be different is the return loss, but even this may not make one bit of difference, when used in a system that has a high return loss by design.

    "Smoke, mirrors, and BS."
     
  14. P Smith

    P Smith Mr. FixAnything

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    Someone is never saw/used BNC connectors ? If not, look at BNC or N-type.
     
  15. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Not sure who this "someone" is that you speak of, but "I'd bet" I've seen and tested more connectors and types than you've seen.
     
  16. P Smith

    P Smith Mr. FixAnything

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    It was directed to other ppl; why it should be picked by you :nono2:
    As to betting ... well, I would - have you tested those micro RF connectors what are using for smartphones, WiFi and Bluetooth boards ?

    [Egh, no need to pondering own chest - there are always someone with bigger fist :), they are just doing own job and not posting here these reports. ]
     
  17. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I only did because your post followed mine, and went sideways with connectors not under discussion in this thread.
     
  18. P Smith

    P Smith Mr. FixAnything

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    I'm usually quoting if I'm going into such detail battle ...
     
  19. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "So noted". :)
     
  20. wallfishman

    wallfishman Icon

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    Im with you. I dont get paid extra to change out all the barrells on every job i do therefore for the last 5 years ive changed none of them. Something old outside ill change, but am i undoing all your wallplates to change free barrells ? LOL. my repeat rate for service calls is great so this isnt creating service calls. i personally think its all a bunch of BS.
     

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