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![]() I haven't had the time to participate in this, but in a brief look, it looks pretty silly. Of course EZNEC shows no current difference across a load. The EZNEC model of a load has zero length, so the current at both terminals has to be the same. You will see a current change over the length of a model of a conductor, because it does have length. The coil in the web site pictures certainly has length, so why should you be surprised to find a current change over its length? W8JI used it as a "proof" that current in the loading coil is virtually the same at both ends. We were not surprised, but W8JI was insisting that it is, used Eznec to prove it (go see his web site) and ridiculed us. Did the experimenter perhaps do the same test with the meters placed the same distance apart with just a conductor in between? Would there be some great revelation in finding that the current was different at the two points? Not to us, but see W8JI arguments speculating and "knowing" that current must be the same. I was intrigued by the claim that a toroid measured significantly different from one end to the other. I wonder if the tester tried reversing the meters to verify that he got the same reading in both cases. If he did, I'd be interested in learning more details. I believe he did use the same method, and W9UCW can answer that. Looks like you are also not getting the main point of the argument. Appears that the rule is: "loading inductance (whatever form) inserted in the radiating element exhibits current magnitudes at its ends corresponding to the current in the length of radiator in electrical degrees that it replaces." Replacing inductance with piece of wire won't do the simulation, it has to have properties of inductor (replacing radiator's segment in degrees, inductance). Toroid, loading stub, and lumped inductors do the same thing. Unfortunately, the main objective of the web site seems to be to insult Tom, W8JI, rather than to be objective. So in my mind that leaves the possibility open that the experimenter is more interested in finding evidence that would disprove Tom than in presenting carefully measured and objective data. Not so, first I posted on eHam.net fact that current is different at the ends of loading coil. To which W8JI rode in with his "answers" and ridiculed me in public (I don't know the laws, didn't read the books, etc.) to which I responded in kind, provided proof and defended my (and others) position. Because this has happened about fifth time (he did it to others too) I simply will not take the crap and bite back. He is parading as a knowitall guru and pontificating with sometimes erroneous information. If anyone questions or challenges that, he does his routine. If you read the trail from the start you would get the picture. If he discussed the matters in a civil manner, there would be no problem, we can exchange arguments, learn something and mainly give a credit where is due. That's what professionals do. He first argues wrong, then goes away for a while and then emerges with change as a guru or inventor. That does not give hams good name and is poor example for those no-coders coming into ham radio. From the past postings, you could probably see that I can discuss the subjects in a civil manner, but when someone who is wrong starts pulling out smart ass remarks and ridicule, the gloves are off and I will defend the truth to the end. It is not just proving Tom wrong, it is to set the record straight, to bring aspect of antenna engineering to light (after 50 years of perpetuation of wrong in some antenna books), to alert software designers to the problem so they can accommodate the proper procedure or workarounds. I hope you can see how inaccurate results will EZnec produce if you simply inserted 0 size inductors in elements of 3 el. 80m shortened parasitic beam. Magnitudes and current distribution will be off, producing skewed results. Optimizing programs will be chasing wrong tail. Again, I apologize for the tone, but I will not give in to the bully. If he doesn't learn and shape up, I will be at his case, pointing out the wrongs that he is disseminating (he has some more on his web site). We were hoping that you were around, following the discussions, helping to point where we are wrong, suggest workarounds or proper procedure for modeling and we are willing to help with testing and verifications. Cecil brought some insight from the theoretical side, I (and W9UCW?) can do measurements and all this can bring greater understanding of the phenomena, rather than propagating misconceptions and wrong ideas. I found a lot more help and expertise on this NG than on eHam.net no-code flat earth society, for which I am grateful. Can we now look at the modeling problems? Seems that Cecil's way of substituting the lumped inductance with loading stubs allows closer approximation of configuration for the modeling programs. But this can still distort the true picture. I would like to point out, that W6?? replaced loading stubs in 3 el. 80m KLM beam with coils and the performance of the beam, especially pattern improved tremendously. So it looks like loading wires and radiation from them (folded along the element) upset the current distribution and resulting deterioration of performance. (So much for nice, low loss loading.) This was done, tested, measured and verified, no speculations. Is there better way of modeling the case, can we use cosine of degree of electrical length of wire that coil replaces? Roy Lewallen, W7EL Yuri, K3BU |
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