Ground loop fix?

Discussion in 'Archived Threads 2001-2004' started by John Williams, Jun 17, 2001.

  1. John Williams

    John Williams Auditioning

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    I am getting some lovely hum and transformer noise through my HT gear since we moved, and I've managed to trace it down to the coax input cable to my Dish Network receiver.
    Does anyone have suggestions on how to get rid of this? I suppose I could try and get the installer back out again to rework it, but I'm not really looking forward to arguing on the phone with half a dozen people for hours before they agree to send someone out.
    I tried using a MIT ISO-LinQ anti-GL cable I've had for years (which worked wonders on the cable-TV hum I had before going to DSS), but it worked so well, I couldn't get a signal from the dish! No power going back and forth, I guess.
    Any suggestions? Is there any other physical details about the installation I can provide that would help?
    -John
     
  2. carl-s

    carl-s Extra

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    John,
    I would suggest to do some more basic trouble shooting. Since you believe to have isolated the problem to the receiver side,specifically the coax, then I suggest you try the receiver on a different outlet on a different circuit. You might also want to replace the the audio interconnect with another pair in your system that you know aren't a problem. Check the ends of the cable to see if their isn't shielding in the center core. If so, then you will have to reterminate the ends.
    carl
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  3. John Williams

    John Williams Auditioning

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    Carl,
    Thanks for the reply. Checking outside today, I noticed that the grounding block (bar shaped connector with cables running through it???) is not, in fact, grounded to anything!
    Would there be any other physical location where the entire system should be grounded (i.e. at the dish, under the house, etc.), or is that it?
    If that block is the only location, then that's where the problem lies, since it's just a-hanging' there.
    Assuming that's the case...where do I look for a ground source out there? It's installed near my main power inlet box, cable box and phone box on the outside of the house (which happens to be opposite the dish itself.)
    Thanks again!
    -John
     
  4. carl-s

    carl-s Extra

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    John,
    The outside piece you are refering to is a ground connector. It should have 2 screw hole to mount to something as as well as a hole for a #4 copper ground wire. The copper wire should go to a ground rod or if the dish cable is near an outside electrical panel box it could be grounded their, providing that the house is properly grounded. Personally , I prefer seperate ground rods. Each end of the coax connected to the ground connector should be wrapped in a black weatherproof elastic type tape, this is for keeping out moisture and causing shorts.
    If this is an apartment or rental house, you could run a new wire from the dish and get an inhouse Panamax lightening and surge protector,then continue onto the receiver.
    I might add that just becase the groung connector IS NOT connect to anything that will solve the problem. I'm kind of under the impression it's something in the house that the receiver is picking up, not unless the outside connector is picking up something from a transformer, or the cable is cut and is touching some metal. I've been doing electrial for about 18 years and sometime it's a number of things. One of the worse things is to believe that a house is grounded properly when it's not or one outlet has reverse polarity, or no ground at all. You might also have a bad outlet.
    Keep me posted and I will try to assist as much as possible.
    carl
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