This is the Sirio GainMaster Antenna . She has no opposite phase currents. Tne Vector 4000 have powerfuls opposites currents. If you follow the green color seen is the complete phase inversion and zero irradiation of the antenna, you will see that this antenna radiates it completely. This field does not exist in the GM The CST model of a SIRIO VECTOR 4000 antenna diplay this in slow motion in the following animation.. Not see the who will not see There are more individual images ..time during which the antenna irradiation is auto canceled Of course I see what you not see, but you confuse half-wave irradiation with the cone.Both are outdated and not in phase as you say. See that cone leaves a green color that is the variation of field AND PHASE CHANGE. Therefore, the cone is in antiphase(yellow & blues colors) with the rest of the antenna. In any case the emission of the cone gives loss to the antenna. In this picture, we see that the phases are perfectly changed inside and at the bottom of the cone, a part is blue, the other yellow, or that are not in phase if they were on stage. the red color would be the left side and blue on the right, however are extrapolated, with an inverted phase of 180 degrees, so if there is emission is 180 degrees out of phase, which makes NEGATIVE if so be collinear, and in phase, CST modeling both colors would be on the same side. see you the opposite and destructive courrents?? Or you are blinded?? This courrents are inexitent in animation of CST Gainmaster antenna. Justlooking at the colors on the display doesn't tell you everything because it is near-field field intensity, and doesn't necessarily correspond with far-field radiation."When the mast and feedline is included in the model, the "Dominator" falls apart. The exception to this is if we add a groundplane at the junction of the cone and the mast and coax. Many antennas get modeled without proper representation of feedlines." - W8JI. - "I was an engineer at Avanti when the Sigma IV design was being built. It's a J pole- nothing more and nothing less. No magic," - Dale W4OP -
Once again I'll ask you to look at the image that represents the maximum radiation currents and pay lesser attention to the weaker currents during the expanding and collapsing portions of the sinewave. Granted the cheap modeling software you play with does not generate a model for you to visualize any of these principles. At the same time, you must recognize that the gain figures it produces are taken when the source is generating peak current into the load and NOT at weaker points in the sinewave before the field has fully expanded. Do you understand this concept?
While I do respect W8JI as a wealth of information, L.B.Cebik devoted his life to the field of antenna design and helping others to understand it. Did you forget I acknowledge significant CMC currents exist and have been used in a way you do not understand to increase gain in a collinear fashion? Unfortunately Tom has not seen this design modeled in CST and appears to be lacking first hand experience working with it in the field. While you're J-Pole tunes much easier once you decouple the coax from the antenna, try it on the Vector and it has virtually no effect on the match and the signal will go down by the same undetectable amount.
The vast majority of CMC has already been radiated from the four 1/4 wavelength upward radials. That allows radiation from them to combine in the same axis as the longer vertical above it. As far as the "design falling apart when you add a mast and coax", CST and most people with first hand experience disagree. Refer back to the CST model below and pay particular attention to the very small currents on the short mast below the cone. The little current that is flowing on this mast (or coax) just happens to be the same color and phase as everything else on the antenna that is allowed to radiate.
Since you like quoting one of the very few errors I've seen Tom make, why not be the one to help out and draw his attention to the new evidence on this site? You claim to be here to help, now you have your chance to show something other than words. I'm confident he has the background and education needed to understand my collinear experiments prove L.B. Cebik's "Non apparent collinear antenna" comment was dead on target years before CST was available to prove him correct.
With respect to W4OP, he did not work on the Sigma IV project in any way. He was mostly involved with the mobile antennas Avanti made and clearly had no idea what Herb was working on with the Sigma IV. You'll also notice members of the forum you are quoting from promised to follow up on the evidence I've provided there too and nothing to prove the "non apparent collinear" explanation wrong has been produced yet. You cannot prove the impossible no matter how much time you are given.
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