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

It's become clear that the cone effects many things and serves more then one function. It's a tapered transmission line that transforms impedance. It's a shield that confines out of phase radiation. It emits it's own in phase radiation supporting the collinear claim.

Some things that are not so clear is that the antenna performs well with it's top section close to 5/8 wave. Even though changing the top section from 1/2 wave to 5/8 wave would seem to cause a large change in it's drive impedance, the antenna tunes well in either case.

What wavelength radiator works best is still open for debate as far as I'm concerned. The new Vector suggests that 3/4 wave has the best far field gain. Test's that Bob and myself have conducted in the field suggest closer to 7/8 wave produces more far field gain.

The last thing I question is if there is any effect of the hoop playing a part in acting as a counterpoise or ground plane for the upper section. The addition of the loop itself has little impact on the gain of this antenna. It does improve bandwidth and virtually eliminates any directional characteristics from the radials.

With respect to how much productive radiation is coming from the cone. There is no reason to speculate. Refer back to the CST model and you can see exactly how intense this radiation is. Granted it's not as strong as the upper portion of the radiator. However, keep in mind the current is divided into the four radials.

<blockquote data-quote="Shockwave" data-source="post: 252725" data-attributes="member: 10882">It&#039;s become clear that the cone effects many things and serves more then one function. It&#039;s a tapered transmission line that transforms impedance. It&#039;s a shield that confines out of phase radiation. It emits it&#039;s own in phase radiation supporting the collinear claim.Some things that are not so clear is that the antenna performs well with it&#039;s top section close to 5/8 wave. Even though changing the top section from 1/2 wave to 5/8 wave would seem to cause a large change in it&#039;s drive impedance, the antenna tunes well in either case. What wavelength radiator works best is still open for debate as far as I&#039;m concerned. The new Vector suggests that 3/4 wave has the best far field gain. Test&#039;s that Bob and myself have conducted in the field suggest closer to 7/8 wave produces more far field gain.The last thing I question is if there is any effect of the hoop playing a part in acting as a counterpoise or ground plane for the upper section. The addition of the loop itself has little impact on the gain of this antenna. It does improve bandwidth and virtually eliminates any directional characteristics from the radials.With respect to how much productive radiation is coming from the cone. There is no reason to speculate. Refer back to the CST model and you can see exactly how intense this radiation is. Granted it&#039;s not as strong as the upper portion of the radiator. However, keep in mind the current is divided into the four radials.</blockquote>

[QUOTE="Shockwave, post: 252725, member: 10882"] It's become clear that the cone effects many things and serves more then one function. It's a tapered transmission line that transforms impedance. It's a shield that confines out of phase radiation. It emits it's own in phase radiation supporting the collinear claim. Some things that are not so clear is that the antenna performs well with it's top section close to 5/8 wave. Even though changing the top section from 1/2 wave to 5/8 wave would seem to cause a large change in it's drive impedance, the antenna tunes well in either case. What wavelength radiator works best is still open for debate as far as I'm concerned. The new Vector suggests that 3/4 wave has the best far field gain. Test's that Bob and myself have conducted in the field suggest closer to 7/8 wave produces more far field gain. The last thing I question is if there is any effect of the hoop playing a part in acting as a counterpoise or ground plane for the upper section. The addition of the loop itself has little impact on the gain of this antenna. It does improve bandwidth and virtually eliminates any directional characteristics from the radials. With respect to how much productive radiation is coming from the cone. There is no reason to speculate. Refer back to the CST model and you can see exactly how intense this radiation is. Granted it's not as strong as the upper portion of the radiator. However, keep in mind the current is divided into the four radials. [/QUOTE]

Top Bottom