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Thread: “Pixie Dust and Unicorn Tears”

  1. #1
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    Default “Pixie Dust and Unicorn Tears”

    By Chris toph er Koch
    Getting your head around locating
    theory relies on an understanding
    of at least a few simple rules regarding
    the behavior of electricity -- the
    movement of free electrons. Key
    among these is that electricity and
    magnetism are linked. Where electricity
    is present, magnetic fields will
    also be present. Alternating current
    creates a moving magnetic field
    that we call “signal.” The behavior
    of this magnetic field changes predictably
    with changes in the rate of
    the alternating current (frequency).
    But, have you ever felt that there
    were elements of locating theory
    that seemed difficult to understand
    even when explained in supposedly
    simple terms?
    You’re not alone. In his book, “There
    are No Electrons: Electronics for
    Earthlings”, author Kenn Amdahl
    commiserates, “If you find some irritating
    inconsistencies in the electron
    theory, don’t worry... The electron
    theory doesn’t answer these
    questions. It works. That’s why it’s
    not called the electron hypothesis.
    On the other hand, it has never been
    conclusively proven. That’s why it’s
    not called the electron law.” Amdahl
    also writes, “If there is magic in the
    universe, the evidence must surely
    be electricity...”
    One of the things that each of us
    who has studied locating theory is
    familiar with, even if only from the
    user’s manual that came with your
    instrument, is an illustration of signal
    showing it as concentric rings
    of magnetism radiating outward
    from a central conductor. This, we
    are to understand, is how our signal
    would appear from the
    front or the rear, if you
    could crouch down and
    look at your conductor
    head on. This diagram is
    everywhere. It’s so ubiquitous
    that I doubt anyone,
    anywhere, would
    dare assert a copyright
    claim. It’s just what signal
    looks like.
    But hang on for just a
    second. What exactly is
    signal? Signal is a moving
    magnetic field. As
    human beings, we have
    no sensory means to experience
    magnetism. We
    can’t see it, hear it, smell
    it, taste it, or feel it on our
    skin. Magnetism is invisible
    to all human detection.
    This would seem to
    create a serious problem
    for even the most talented
    of illustrators. Add to this difficulty
    that underground utility locating
    relies not just on magnetism, but on
    a moving magnetic field. So, signal
    isn’t just invisible, it’s also on the
    move. And in fact, it’s in one hell of
    a hurry. The lowest frequency signal
    that any of us routinely deals with
    goes through a complete positive
    and negative phase (one full cycle)
    sixty times each second (60Hz or “60
    cycle”). Pity the illustrator for a moment,
    then ask him to also draw it
    from the side (a sine wave).
    With these kinds of challenges to
    understanding locating theory so
    superficially evident, is it any wonder
    that many talented and skilled
    technicians are still a little shaky on
    exactly how it is that they do what
    they do?
    If you’re in rough shape and find
    yourself in the hospital, your doctor
    can have an x-ray done to get
    a look at what’s going on inside
    of you, underneath the surface. If
    that physician needs a really good
    look, they can request an MRI. With
    these sophisticated instruments
    at their disposal and with an advanced
    degree on the wall, one
    thing they won’t do is guarantee
    you what they’ll find when they actually
    open you up.
    With less sophisticated instruments,
    locating technicians from coastto-
    coast head out into the field
    every day to mark unseen utilities
    in crowded rights-of-way under a
    variety of conditions, relying on the
    presence of something they cannot
    physically perceive and whose very
    existence is not fully understood.
    It’s kind of magical when you think
    about it.
    Christopher Koch is president of
    Hance Utility Services and the Locator
    School. Over the past decade, he has
    been responsible for training locators
    in 22 states, Canada and Australia.
    Koch currently serves as President
    of NULCA and helped craft the 2009
    revision to the NULCA Competency
    Standard. He can be reached by email
    Common signal

  2. #2
    Senior Member yahoo's Avatar
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    Default Re: “Pixie Dust and Unicorn Tears”

    THAT is some good stuff. Never thought to look at it like that!
    wise men talk because they have something to say and fools because they have to say something....plato

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