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SW, I think you're right about checking the current flow right below the antenna. I just checked one of my Sigma model's current reports with a non-insulated mast attached, and it shows a 1/4 wavelength of mast below the antenna that is in-phase and probably radiating a little. It is also showing more current flowing by an increase of 95% compared to the insulated mast as follows: .08123A/.004535A as an example of one segment in that area of the mast.

I agree this would make a difference if in-phase with the radiator, and that may help explain the remarkable increase noted in the patterns that I posted above...in favor of the non-insulated mast. If this 1/4 also radiates at 7* like the radiator it may show some benefits, but how do we know. Showing some gain with a model is not always the same as how it responds in the real world.

SW my stuff seems to disagrees with your claims. My models of the 5/8 wave shows much more current flowing on the mast than with the Vector. The currents right below the ground planes are also in-phase with the radials and the radiator, just like on my Sigma4/Vector models. My 5/8 wave models also show a decrease in gain when insulating the mast, but the gain difference is very slight, just as you note.

I have nothing to compare my models with except for the Gain Master model I made by adjusting a 1/2 wave dipole to simulate this new antenna. To me the output results were strikingly similar to the stuff that Sirio published in their GM Manual and they said they were using new top of the line modeling software. Seeing some modeling from others will be helpful in better understanding any mistakes I make.

<blockquote data-quote="Marconi" data-source="post: 243048" data-attributes="member: 903">SW, I think you&#039;re right about checking the current flow right below the antenna. I just checked one of my Sigma model&#039;s current reports with a non-insulated mast attached, and it shows a 1/4 wavelength of mast below the antenna that is in-phase and probably radiating a little. It is also showing more current flowing by an increase of 95% compared to the insulated mast as follows: .08123A/.004535A as an example of one segment in that area of the mast. &nbsp;I agree this would make a difference if in-phase with the radiator, and that may help explain the remarkable increase noted in the patterns that I posted above...in favor of the non-insulated mast. If this 1/4 also radiates at 7* like the radiator it may show some benefits, but how do we know. Showing some gain with a model is not always the same as how it responds in the real world.&nbsp;SW my stuff seems to disagrees with your claims. My models of the 5/8 wave shows much more current flowing on the mast than with the Vector. The currents right below the ground planes are also in-phase with the radials and the radiator, just like on my Sigma4/Vector models. My 5/8 wave models also show a decrease in gain when insulating the mast, but the gain difference is very slight, just as you note.&nbsp; &nbsp;I have nothing to compare my models with except for the Gain Master model I made by adjusting a 1/2 wave dipole to simulate this new antenna. To me the output results were strikingly similar to the stuff that Sirio published in their GM Manual and they said they were using new top of the line modeling software. Seeing some modeling from others will be helpful in better understanding any mistakes I make.</blockquote>

[QUOTE="Marconi, post: 243048, member: 903"] SW, I think you're right about checking the current flow right below the antenna. I just checked one of my Sigma model's current reports with a non-insulated mast attached, and it shows a 1/4 wavelength of mast below the antenna that is in-phase and probably radiating a little. It is also showing more current flowing by an increase of 95% compared to the insulated mast as follows: .08123A/.004535A as an example of one segment in that area of the mast. I agree this would make a difference if in-phase with the radiator, and that may help explain the remarkable increase noted in the patterns that I posted above...in favor of the non-insulated mast. If this 1/4 also radiates at 7* like the radiator it may show some benefits, but how do we know. Showing some gain with a model is not always the same as how it responds in the real world. SW my stuff seems to disagrees with your claims. My models of the 5/8 wave shows much more current flowing on the mast than with the Vector. The currents right below the ground planes are also in-phase with the radials and the radiator, just like on my Sigma4/Vector models. My 5/8 wave models also show a decrease in gain when insulating the mast, but the gain difference is very slight, just as you note. I have nothing to compare my models with except for the Gain Master model I made by adjusting a 1/2 wave dipole to simulate this new antenna. To me the output results were strikingly similar to the stuff that Sirio published in their GM Manual and they said they were using new top of the line modeling software. Seeing some modeling from others will be helpful in better understanding any mistakes I make. [/QUOTE]

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