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.