[NSRCA-discussion] interference

[Fred Huber]

Its not just distance.

its not just length relative to radio wavelenght (but that is a major factor...)

Is that extra strand grounded?  is it effectively connected to the + batt wire, the - batt wire or the signal wire?  THAT will be a HUGE factor.

Metal gear.. Metal wire, metal clevice, CF or otherwise conductive output arm on the servo and the post on the pot of the servo... you might have a ground path to the electronics of the servo.
  ----- Original Message ----- 
  From: Jerry Jackson 
  To: NSRCA Mailing List 
  Sent: Tuesday, February 20, 2007 8:12 PM
  Subject: Re: [NSRCA-discussion] interference


  I want to pose a set of hypothetical situations regarding conductors in close proximity to receiving antennas and invite comments on the likelihood of adverse effects.

  #1 Suppose we add one more bare strand to the multi-strand wire we use for antennas.  I think we can all agree that this would not cause a problem.

  #2 Nearly the same situation as #1 but in this case the new strand has very thin enamel insulation and its ends are open circuited.  The new wire is parallel to the antenna and is only a thousandth of an inch away. Will this cause a problem?  I think not.

  #3 Nearly the same situation as #2 but in this case the new strand is place just outside the vinyl jacket of the antenna. The new wire is parallel to the antenna but now it is separated by maybe 20 thousandth of an inch from the other conductors.  Will this cause a problem? I think not.

  #4.Lets move the new strand of wire 100 feet away but it is still parallel to the antenna.  Will this cause a problem? I think not.

  So the question is, is there some critical separation distance that will let the new strand cause problems? And what is it?

  JJ

  --------------
    ----- Original Message ----- 
    From: Del K. Rykert 
    To: NSRCA Mailing List 
    Sent: Tuesday, February 20, 2007 3:48 PM
    Subject: Re: [NSRCA-discussion] interference


    Not dis-agreeing with what Ed has shared but I wanted to share another added factor of what happens when running metal parallel with a receiving antenna. From my ham radio knowledge other metal wires/rods can influence the intended receiving antenna as they can become reflectors or directors that influence the received signal. That in turn may cause the receiver to receive distorted signals which of course cause fits for the receiver. It was less of an issue when people ran the receiver antenna outside of the fuse. Now many run them down the fuse in a tube which is typically parallel to the pushrods.  
        Only meant to help the understanding of what can occur when metal on metal noise is not the culprit. 

        Del
      ----- Original Message ----- 
      From: Ed Deaver 
      To: NSRCA Mailing List 
      Sent: Monday, February 19, 2007 7:56 PM
      Subject: Re: [NSRCA-discussion] interference


      My understanding is this is only a real problem if the offending wires are all connected in essence making a metal square.  Tail wires on a flat stab, using metal conneters to metal hold downs to metal bolts make a complete square.

      If you used some form of carbon connectors, breaking the square it shouldn't be a problem.  Have used metal on all my 40%'s as well as pattern planes w/o problems.

      Ed

      jfgreen <jf217green at cmc.net> wrote:
        In an effort to avoid turning my new pattern ship into a dirt seeking comet similar to my last Oly, I've been researching some possible causes,  I recently read from one source that one would or could have interference problems if when using steel pull-pull cables and installing the antenna parallel to them inside the fuse.  I have seen a number of AC at contests w/this configuration that seem to have no interference problems.  Your  experience, thoughts please.  THX - Jerry
         


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