Velocity of propagation

Discussion in 'Physics' started by emef, Sep 3, 2005.

  1. emef

    Thread Starter New Member

    Sep 3, 2005
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    I am reading a paper in which it is maintained that VOP in a non-inductively wound conductor is infinite, based on the use of the formula:
    VOP=C / √ue
    where C is the vacuum velocity of light, u is magnetic permeability, and e is dielectric constant.
    It is maintained that when u or e is zero, the VOP is infinite, and in a non-inductively wound conductor, u is shown to be zero due to cancellation of induced magnetic fields in the windings of the conductor.
    I have only seen the formula:
    VOP=C / √e
    in my rather limited reading.
    Should the permeability be in there or not, and if so why is it sometimes omitted?
    Can anyone shed any light on this?
     
  2. n9xv

    Senior Member

    Jan 18, 2005
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    The formula;

    VOP=C / √ue

    is used specifically to denote the VOP in air.
     
  3. Dave

    Retired Moderator

    Nov 17, 2003
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    Could you supply a link to the paper so that we can have a look, or perharps take relevant excerts (please remember to attribute all explicit references from the document).

    As far as I'm concerened VOP ina medium is defined as a percentage with respect to VOP in a vacuum and that a VOP of 100% is the absolute maximum bound by Special Relativity, i.e. VOP = C. There is a chance I've got the wrong end of the stick, but a bit of clarification is requied.

    Thanks.
     
  4. emef

    Thread Starter New Member

    Sep 3, 2005
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  5. emef

    Thread Starter New Member

    Sep 3, 2005
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    Thanks guys for your prompt replies.
    I'm not sure I'm using the reply mechanism correctly unfortunately. I already tried to send a reply but when I used the preview button my reply seemed to disappear, so I'm trying again. I hope I haven't made too much of a mess on the board.
    I don't think there is any link to this paper. The author is Harvey Morgan and is deceased. I found an obituary notice when I tried to contact him.
    The publication appears under the title: "Now We Can Explore the Universe" in IEEE AES Systems Magazine, January 1998 pp 5-10.
    I agree with what you have said Dave, for an electromagnetic wave travelling freely through a medium, but he is discussing transmission along a non-inductively wound conductor. This is what I'm puzzled about, (as well as many other things in his paper). It's possible it's a lot of nonsense.
    Anyway please read his paper if you can, and I would be grateful to hear your thoughts.

    Here goes, this time I'll just hit the Add reply button.

    Thanks.
     
  6. Dave

    Retired Moderator

    Nov 17, 2003
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    Hi emef,

    I have had a look around on Google and can't find anything on this paper. To go back to your original question about a VOP of infinity, well unless there is another interpretation of VOP, to me that is impossible.

    By definition:

    Velocity of propagation is the speed of signal transmission relative to the speed of light in a vacuum.

    That is:

    VOP(medium) = [Velocity of signal transmission(medium) / velocity of light (vacuum)] x 100

    Therefore:

    Velocity of light(vacuum) = 1/ √ (μo x ε0) ≈ 3e8

    Where the relative permittivity and permeability ( μr and εr) are equal to 1.

    (Remember the dielectric constant is (μo x μr x ε0 x εr))

    VOP(vacuum) = (velocity of light(vacuum) / C) = 1

    Or 100%

    The VOP in other mediums, is dictated by the two relative values above, which will always be greater than or equal to 1. Therefore by just analysis the maths of the problem we can see that the VOP will never exceed VOP(vacuum) - this is in some ways a very simple mathematical proof of what is explained by Special Relativity (note it is not a proof of Special Relativity itself!)

    So to me this idea of an infinite VOP is not realisable. As for the impact of the non-inductively wound conductor, I assume this merely means a conductor where the inductance is negligible. If this is the case then there is no reason the VOP should be infinite.

    Just out of curiosity, is the equation you quoted in your opening post (VOP=C / √ue) quoted directly from the paper? Its wrong.
     
  7. emef

    Thread Starter New Member

    Sep 3, 2005
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    Hi Dave,

    Yes the equation is quoted directly from the paper as in my first post. He just states that u and e are permeability and dielectric respectively. He doesn't state whether they are vacuum values or relative values, but I assume he means they refer to the non-inductively wound conductor, which would therefore make them relative values. Quoting Morgan "When u or e is zero, the indicated VOP is infinite. The mechanism for making VOP infinite is cancellation of magnetic fields associated with signal current.......The technique by which magnetic field cancellation is accomplished and a conductor is rendered non-inductive is to have equal currents in opposite directions......A length of conductor is doubled from the middle back to the start so that the current at any point on the doubled conductor is equal and opposite in conductors side-by-side, in contact.....With two conductors carrying equal current in opposite directions, the tendencies for magnetic fields are equal and opposite; so they cancel.
    On a non-inductive cable, the current leaves the source and returns to it. At the far end of the cable, the information of the signal needs to be transferred to the signal destination. A transformer primary connected to the two conductors of the cable will pass the signal current without change." End of quote.

    He then goes on to report experimental proof that total cancellation of magnetic fields does in fact occur, hence rendering u completely zero, (not just simply small), and thus making VOP infinite. He actually goes on to describe the results of an experiment to measure it, and finds it to be infinite within his experimental limits.

    I hope this provides some food for thought.
     
  8. Dave

    Retired Moderator

    Nov 17, 2003
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    Thanks for the post and quotes emef, I can see the Mathematics of what Morgan is saying, without truely grasping what exactly is happening. What I understan about VOP is clearly a differnt thing (although not entirely) from what Morgan is discussing in his paper.

    I will continue to look around on the Internet because this is quite an interesting topic, even though a Google search for Harvey Morgan Velocity of propagation only returns 2 results (nearly a Googlewhack!)

    I did find that within the said paper that Morgan demonstrates that a spinning flywheel positioned 1/16" from another flywheel causes a movement in the second flywheel that defies Newton's Laws due to a spin field momentum in the first flywheel. Just a side observation.

    I'd also like to make a correction to my earlier post which said: Remember the dielectric constant is (μo x μr x ε0 x εr). This is nonsense, although the conecpt still stands, although after taking part in this discussion, I'm not sure it does.
     
  9. emef

    Thread Starter New Member

    Sep 3, 2005
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    Hi Dave,
    I started this discussion because I was suspicious that there was a fallacy in the use of the formula by Harvey Morgan. Also I found in Wikipedia, VOP given by C/√e without mention of u and I wanted to know why u was not present.
    I believe I may have found the reasons for both these questions now in the online book "All about circuits" in the website which hosts this very forum. In Volume2, Chapter 13, Transmission Lines, Characteristic Impedance, dealing with transmission in coaxial cables, the formula is given as:

    Velocity Factor =v/C=1/ √ k

    where v=Velocity of wave propagation
    C=Velocity of light in a vacuum
    k=Relative permittivity of insulation between conductors.
    It is clearly stated that it is a function only of k, the relative permittivity.
    However since I have not worked through any derivation of this formula I still do not understand why permeability does not come into it.
    Harvey's formula applies to the velocity of light freely travelling in a vacuum, but maybe it is not applicable to his non-inductive conductors.
    If this should be the case, whether his conductor is non-inductive or not, would appear to be irrelevant.
    He claims to have measured the VOP as infinite, but his wiring system extended only over 20 metres and I wonder if his measurements could distiguish between infinite speed and merely approaching closely the speed of light, as I believe is quite possible for an electric wave in a normal conductor. However it is quite possible that I am wrong about this.
    Anyway I'll do a bit more reading in the above mentioned book.
     
  10. Dave

    Retired Moderator

    Nov 17, 2003
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    Hi emef,

    When you ask where does the permeabilty come into it well think about this:

    Velocity Factor = 1 / √ k

    Where k is the relative permittivity (also referred to as εr) which in turn is defined by:

    k = εr = ε / εo

    Where ε is the static permittivity and εo is the permittivity of free space.

    Also recall that:

    εo = 1 /(c^2 x μo)

    Where μo is the permeability of free space.

    So your velocity factor is indirectly affected by the permeability, however is independant of the permeability of the medium. Just a casual observation.

    Further to the information here on AAC about TM lines I'd like to bring to your attention the following link from Berkeley. http://inst.eecs.berkeley.edu/~ee117/sp04/lect/lecture1.pdf

    This was the introductory lecture I took in a TM Lines and EM Waves course at University. It explains, through deriavtion of the Wave Equation, the concept of wave velocity on a transmission line. I also did some research in this subject some time ago, looking at how to model miniture transmission lines in a laboratory which reflected a real transmission line. As a part of my work I assumed that the wave velocity along the line was equal to the speed of light and I was able to create a transmission line model which was accurate to less than 2% (something I was able to verify through analysis of the model in the frequency domain). Although this is side observation from the discussion at hand, I thought I would mention this point.

    Anyway, I am away now till Monday, so won't be able to reply till then. I shall have a good think about this problem when I get a moment to myself. I am still struggling with the idea of infinite VOP and hence the concept of faster than the speed of light. I suppose one does not adapt well to change.

    Good topic.
     
  11. MaxL

    New Member

    Sep 3, 2006
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    Hi emef,
    TM lines refer to capacitance and inductance in the caracteristics. If a signal is applied to a circuit that is non-capacitive and non-inductive, then the VOP is infinite. I have conducted an experiment with 300 metres of wire and a dual trace cro and expected to see 1uS delay. There was none!
    Please let me know if you want further information on constructing the experiment. It shows Kirchhoff's Laws do work at every instant of time.
     
  12. Dave

    Retired Moderator

    Nov 17, 2003
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    Please do elaborate.

    Dave
     
  13. Gadget

    Distinguished Member

    Jan 10, 2006
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    This is all a bit too much math for me, but you gotta love a forum that questions Einstein.
     
  14. Dave

    Retired Moderator

    Nov 17, 2003
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    Nothing goes unchallenged! :D

    Dave
     
  15. thingmaker3

    Retired Moderator

    May 16, 2005
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    How do we achieve zero capacitance and zero inductance in the real world?
     
  16. beenthere

    Retired Moderator

    Apr 20, 2004
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    Hi,

    Some more inspired fiddlings with the underlying mechanism of the universe.

    I like the spaced flywheels demo - are they in vacuum, or in air? If in air, there is a more likely coupling mechanism working.

    As far as a non-inductive conductor - good luck. Any conductor has to build a magnetic field around itself while conducting. The formula for calculating the length of elements in antennas uses 96% of C for the calculation, as the propogation in the metal elements is less than C in vacuuum by very nearly 4%.

    For more reading in this area (people who tried to make a different universe than the one observed), try looking up the Farnsworth Fusor. Philo T. farnsworth was the man who invented and made most of the significant discoreries about television, but he took a funny turn about being able to construct a vacuum tube that could cause nuclear fusing inside four special chambers.
     
  17. MaxL

    New Member

    Sep 3, 2006
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    It's great to see some other sceptics out there!
    Anyway, here is a doc describing the experiment.
    I hope some of you will take the time and effort to build it.
     
  18. beenthere

    Retired Moderator

    Apr 20, 2004
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    Hi,

    It's more than being sceptical - the vacuum of space is reasonably free of inductance and capacitance, yet C is limited to the experimental value. It is not infinite.

    Also demonstrated by many experiments - C drops in value in any medium other than a vacuum. Not even series ading magnets will let C increase in a transmission line. Not even pulling a vacuum around the conductor.

    The effect would, however, be a real aid in making perpetual motion practical.
     
  19. Dave

    Retired Moderator

    Nov 17, 2003
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    Hi MaxL,

    Your experiment seems very thorough but the above attached document seems to have no results you obtained from this experiment, it only appears to propose an experiment and gesture to a thought exercise. So while the details contained within your attached document are for many of us, nothing startling or new, we need you to share the results that allow you to come to the conclusion:

    Dave
     
  20. MaxL

    New Member

    Sep 3, 2006
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    Sorry about that, anyway here is a pic.
    Top trace is input signal.
     
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