You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
The Feb 2025 Radioddity Giveaway Results are In! Click Here to see who won!

Reply to thread

Message

Bob, I'm sorry I have not addressed your question about the length of the radiation current on the upper 1/2 wave appearing longer at some frames in the model. There are several media players that allow you to freeze the video and display exactly what you're talking about. To me it appears we are seeing the results of the multiple currents interacting with each other prior to the currents reaching the source phase that produces the final pattern at full currents. I see two possible reasons contributing to this.

The dominant factor seems to be the two opposing currents inside the cone. While I wouldn't normally expect the current on the cone to "force" the current on the vertical up higher on the element, that appears to be what we see happening in the CST model. When the currents are viewed at a weak point during the drive phase, the opposing current may find the "path of least resistance" is to repel higher on the vertical before the currents reach a magnitude where they are forced to "fit" along the radiator length.

Had all currents been equal in the opposing areas, I suspect we would see much less movement of the current on the vertical throughout the drive phase. Which leeds me to the second contributor that dispells Marconi's "very little cone radiation idea". The fact that CMC on the outside of the cone is dependant on the antenna having radiated a current in order to cause the imbalance required to create the CMC in the first place. The delay in seeing the expected phase alignment along the vertical may be effected by this too.

<blockquote data-quote="Shockwave" data-source="post: 500506" data-attributes="member: 10882">Bob, I&#039;m sorry I have not addressed your question about the length of the radiation current on the upper 1/2 wave appearing longer at some frames in the model. There are several media players that allow you to freeze the video and display exactly what you&#039;re talking about. To me it appears we are seeing the results of the multiple currents interacting with each other prior to the currents reaching the source phase that produces the final pattern at full currents. I see two possible reasons contributing to this.&nbsp;The dominant factor seems to be the two opposing currents inside the cone. While I wouldn&#039;t normally expect the current on the cone to &quot;force&quot; the current on the vertical up higher on the element, that appears to be what we see happening in the CST model. When the currents are viewed at a weak point during the drive phase, the opposing current may find the &quot;path of least resistance&quot; is to repel higher on the vertical before the currents reach a magnitude where they are forced to &quot;fit&quot; along the radiator length.&nbsp;Had all currents been equal in the opposing areas, I suspect we would see much less movement of the current on the vertical throughout the drive phase. Which leeds me to the second contributor that dispells Marconi&#039;s &quot;very little cone radiation idea&quot;. The fact that CMC on the outside of the cone is dependant on the antenna having radiated a current in order to cause the imbalance required to create the CMC in the first place. The delay in seeing the expected phase alignment along the vertical may be effected by this too.</blockquote>

[QUOTE="Shockwave, post: 500506, member: 10882"] Bob, I'm sorry I have not addressed your question about the length of the radiation current on the upper 1/2 wave appearing longer at some frames in the model. There are several media players that allow you to freeze the video and display exactly what you're talking about. To me it appears we are seeing the results of the multiple currents interacting with each other prior to the currents reaching the source phase that produces the final pattern at full currents. I see two possible reasons contributing to this. The dominant factor seems to be the two opposing currents inside the cone. While I wouldn't normally expect the current on the cone to "force" the current on the vertical up higher on the element, that appears to be what we see happening in the CST model. When the currents are viewed at a weak point during the drive phase, the opposing current may find the "path of least resistance" is to repel higher on the vertical before the currents reach a magnitude where they are forced to "fit" along the radiator length. Had all currents been equal in the opposing areas, I suspect we would see much less movement of the current on the vertical throughout the drive phase. Which leeds me to the second contributor that dispells Marconi's "very little cone radiation idea". The fact that CMC on the outside of the cone is dependant on the antenna having radiated a current in order to cause the imbalance required to create the CMC in the first place. The delay in seeing the expected phase alignment along the vertical may be effected by this too. [/QUOTE]

Top Bottom