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

This is an initial look at the 5/8 over 3/8 groundplane collinear concept. My model is not based on the dimensions of the G-Max, although it will be compared to them with my thoughts given as well.

The model I made has a feedpoint impedance of 68.9 - j0.24, which is an SWR of 1.38 and very close to resonance, not bad for an initial look at a design concept...

Also my model is modeled at 1 wavelength above the earth, matching the models from the site. With certain similarities between said models I believe them on this, so I don't think they mounted the antenna super high to overhype said gain.

For reference, this is the data taken directly from the Grazioli antenna site. It is all one image, so I am posting it as is. We will be comparing the middle and right sections of this image.

[ATTACH=full]72361[/ATTACH]
My current and phase looks similar to the G-Max.

[ATTACH=full]72362[/ATTACH]

As their current distribution comes very close to my 5/8 over 3/8 design, I wonder where they came up with the 5/8 over 1/4 idea? Using a loading coil, such an idea is possible, but I just don't see why they would say that for this antenna...

Now for the gain...

[ATTACH=full]72363[/ATTACH]

I get far less gain, and the patterns are different. I'm not 100% sure why yet, and I don't have time to play anymore, have to get ready for work... From what I can tell, the angles of radiation are 1 degree off of each other, so in the regard we are in the same boat. I have far less gain than they do. This could be due to a combination of any number of things, different ground, I used aluminum elements and they used perfect conductors, different dimensions, ect.

This structure is already in the range of 75% efficient, which means 25% of the signal is being lost before the radiation happens. I'm pretty sure that if I adjust the lengths of the upper and lower sections I should be able to pick up more gain, and change the model so that it more closely matches the one they provide, but I doubt there is 2 dB worth of gain to pick up...

When I next get a chance I will have to experiment with using perfect conductors, and with adjusting the dimensions of the antenna.

The DB

<blockquote data-quote="The DB" data-source="post: 855268" data-attributes="member: 21346">This is an initial look at the 5/8 over 3/8 groundplane collinear concept.&nbsp; My model is not based on the dimensions of the G-Max, although it will be compared to them with my thoughts given as well.The model I made has a feedpoint impedance of 68.9 - j0.24, which is an SWR of 1.38 and very close to resonance, not bad for an initial look at a design concept...Also my model is modeled at 1 wavelength above the earth, matching the models from the site.&nbsp; With certain similarities between said models I believe them on this, so I don&#039;t think they mounted the antenna super high to overhype said gain.For reference, this is the data taken directly from the Grazioli antenna site.&nbsp; It is all one image, so I am posting it as is.&nbsp; We will be comparing the middle and right sections of this image.[ATTACH=full]72361[/ATTACH]My current and phase looks similar to the G-Max.[ATTACH=full]72362[/ATTACH]As their current distribution comes very close to my 5/8 over 3/8 design, I wonder where they came up with the 5/8 over 1/4 idea?&nbsp; Using a loading coil, such an idea is possible, but I just don&#039;t see why they would say that for this antenna...Now for the gain...[ATTACH=full]72363[/ATTACH]I get far less gain, and the patterns are different.&nbsp; I&#039;m not 100% sure why yet, and I don&#039;t have time to play anymore, have to get ready for work...&nbsp; From what I can tell, the angles of radiation are 1 degree off of each other, so in the regard we are in the same boat.&nbsp; I have far less gain than they do.&nbsp; This could be due to a combination of any number of things, different ground, I used aluminum elements and they used perfect conductors, different dimensions, ect.This structure is already in the range of 75% efficient, which means 25% of the signal is being lost before the radiation happens.&nbsp; I&#039;m pretty sure that if I adjust the lengths of the upper and lower sections I should be able to pick up more gain, and change the model so that it more closely matches the one they provide, but I doubt there is 2 dB worth of gain to pick up...When I next get a chance I will have to experiment with using perfect conductors, and with adjusting the dimensions of the antenna.The DB</blockquote>

[QUOTE="The DB, post: 855268, member: 21346"] This is an initial look at the 5/8 over 3/8 groundplane collinear concept. My model is not based on the dimensions of the G-Max, although it will be compared to them with my thoughts given as well. The model I made has a feedpoint impedance of 68.9 - j0.24, which is an SWR of 1.38 and very close to resonance, not bad for an initial look at a design concept... Also my model is modeled at 1 wavelength above the earth, matching the models from the site. With certain similarities between said models I believe them on this, so I don't think they mounted the antenna super high to overhype said gain. For reference, this is the data taken directly from the Grazioli antenna site. It is all one image, so I am posting it as is. We will be comparing the middle and right sections of this image. [ATTACH type="full" size="1207x384"]72361[/ATTACH] My current and phase looks similar to the G-Max. [ATTACH type="full" size="573x560"]72362[/ATTACH] As their current distribution comes very close to my 5/8 over 3/8 design, I wonder where they came up with the 5/8 over 1/4 idea? Using a loading coil, such an idea is possible, but I just don't see why they would say that for this antenna... Now for the gain... [ATTACH type="full" size="380x379"]72363[/ATTACH] I get far less gain, and the patterns are different. I'm not 100% sure why yet, and I don't have time to play anymore, have to get ready for work... From what I can tell, the angles of radiation are 1 degree off of each other, so in the regard we are in the same boat. I have far less gain than they do. This could be due to a combination of any number of things, different ground, I used aluminum elements and they used perfect conductors, different dimensions, ect. This structure is already in the range of 75% efficient, which means 25% of the signal is being lost before the radiation happens. I'm pretty sure that if I adjust the lengths of the upper and lower sections I should be able to pick up more gain, and change the model so that it more closely matches the one they provide, but I doubt there is 2 dB worth of gain to pick up... When I next get a chance I will have to experiment with using perfect conductors, and with adjusting the dimensions of the antenna. The DB [/QUOTE]

Top Bottom