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The CST model is shown with a 1/2 wave top element like the new Vector. This can be determined by noting the model has all radiation currents in a constructive phase. If it were the old 7/8 wave we would see approximately 1/8 wave of the vertical radiator above the cone, out of phase with the rest of the antenna much like we do in a typical 5/8 wave. I don't have access to any old Vector CST models and I'm not aware of any.

The longer length used in the new cone is producing improved performance. Bob and myself both noticed this years before the new Vector came out deviating from the old 94 inch length. This has to do with the fact the cone is not just a 1/4 wave radiator, it must also be positioned correctly so that it covers the bottom 1/4 wave of the vertical. Combine this with the velocity factor between the cone and the vertical and you can quickly see there are several different areas affecting the optimal alignment.

I've found .82 wavelength from the feedpoint to the tip gives the best performance. Bob feels that these lengths can be altered to tailor the angle of radiation to best suit a particular installation. Many would be quick to deny this fact assuming only height above ground could impact TOA. We have a "non apparent collinear" here and with two active elements radiating, beam tilt is possible by altering the phase angle between the two. I don't think that was considered when the antenna was shrunk back down to 3/4 wave.

<blockquote data-quote="Shockwave" data-source="post: 405076" data-attributes="member: 10882">The CST model is shown with a 1/2 wave top element like the new Vector. This can be determined by noting the model has all radiation currents in a constructive phase. If it were the old 7/8 wave we would see approximately 1/8 wave of the vertical radiator above the cone, out of phase with the rest of the antenna much like we do in a typical 5/8 wave. I don&#039;t have access to any old Vector CST models and I&#039;m not aware of any.The longer length used in the new cone is producing improved performance. Bob and myself both noticed this years before the new Vector came out deviating from the old 94 inch length. This has to do with the fact the cone is not just a 1/4 wave radiator, it must also be positioned correctly so that it covers the bottom 1/4 wave of the vertical. Combine this with the velocity factor between the cone and the vertical and you can quickly see there are several different areas affecting the optimal alignment.I&#039;ve found .82 wavelength from the feedpoint to the tip gives the best performance. Bob feels that these lengths can be altered to tailor the angle of radiation to best suit a particular installation. Many would be quick to deny this fact assuming only height above ground could impact TOA. We have a &quot;non apparent collinear&quot; here and with two active elements radiating, beam tilt is possible by altering the phase angle between the two. I don&#039;t think that was considered when the antenna was shrunk back down to 3/4 wave.</blockquote>

[QUOTE="Shockwave, post: 405076, member: 10882"] The CST model is shown with a 1/2 wave top element like the new Vector. This can be determined by noting the model has all radiation currents in a constructive phase. If it were the old 7/8 wave we would see approximately 1/8 wave of the vertical radiator above the cone, out of phase with the rest of the antenna much like we do in a typical 5/8 wave. I don't have access to any old Vector CST models and I'm not aware of any. The longer length used in the new cone is producing improved performance. Bob and myself both noticed this years before the new Vector came out deviating from the old 94 inch length. This has to do with the fact the cone is not just a 1/4 wave radiator, it must also be positioned correctly so that it covers the bottom 1/4 wave of the vertical. Combine this with the velocity factor between the cone and the vertical and you can quickly see there are several different areas affecting the optimal alignment. I've found .82 wavelength from the feedpoint to the tip gives the best performance. Bob feels that these lengths can be altered to tailor the angle of radiation to best suit a particular installation. Many would be quick to deny this fact assuming only height above ground could impact TOA. We have a "non apparent collinear" here and with two active elements radiating, beam tilt is possible by altering the phase angle between the two. I don't think that was considered when the antenna was shrunk back down to 3/4 wave. [/QUOTE]

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