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

So, as no one else had anything to add, I will show some of my initial results here.

The first image is created with 4nec2. It is looking at the radiation pattern on the horizontal plane, or like you are looking down on it from above. The antenna was mounted 10 feet above the earth, and this version of the antenna is made out of 100% horizontal wires. Also, the radiation pattern that is shown is at an angle of 59 degrees above the horizon. There are two reason this angle is what has been shown. One, it is the default angle that the modeling software used, which happens to be where the antenna's peak total gain happens to be. And two, it is able to show where both the vertical and horizontal components in one screenshot, so there is no confusion that the modeling software is showing that this modeling software is showing both polarizations being radiated.

Also, the conventions for these images. The orientation, the Y axis, or from our pints of view up and down, will always be in line with the vehicle facing its front and back. The X axis is the same vehicle, but the left and right sides. This is in conjunction with how the pictures above show how this antenna is mounted to a vehicle.

[photo=large]6732[/photo]

The green line is the total combined gain, the red line is horizontal gain, and the blue line is vertical gain.

This is a test model that shows, again, that this antenna is in fact producing vertically polarized radiation.

So the question is why? I stated above that this model, which is similar to the Super Sinner antenna is made up of 100% horizontal wires. Where is this vertical component coming from?

The next step was to check these results with another program, so I made a model with the same dimensions using Mmana-Gal, a mininec based modeling software, and got these results.

[photo=large]6731[/photo]

In this case, the model that matches what is shown above is on the left. As far as vertical and horizontal polarization, the colors are reversed with this program. I don't know if there is a way to change the color layout, and this is likely the only model I will use from this program so I will just let it be this time. So while in 4nec2 horizontal polarized gain is shown with a red line, here it is shown with a blue line. The opposite is true for vertical radiation. I should also point out that this software is showing gain at 45 degrees off of the horizon, again the program's default when running this model. However, while this is a different angle, the result is clear, there is vertical polarized gain present.

So what does this mean. These programs use two different implementations of what is called the "Method of Moments" or MOM. Because of this, as both show a vertical component, it is very unlikely that this is just a software issue.

Because of what I stated above, its likely not a software error. So, where does this vertically polarized gain come from?

One thought I had was that the earth might play a part, any while I said I didn't think it was, it was easy enough to look into, so here I am going to model the antenna in frees-space to rule out the effects of the earth.

[photo=large]6730[/photo]

Here we see a free-space model of the antenna, again at 59 degrees above the horizon, just like the initial test model above. And here we also see that the vertical component is still present. This rules out the earth below the antenna being the cause of said vertically polarized radiation..

That is all I have for now, from here I will try changing the model layout in various ways to see what happens. That, however, will have to wait until I have more time.

The DB

<blockquote data-quote="The DB" data-source="post: 777774" data-attributes="member: 21346">So, as no one else had anything to add, I will show some of my initial results here.The first image is created with 4nec2.&nbsp; It is looking at the radiation pattern on the horizontal plane, or like you are looking down on it from above.&nbsp; The antenna was mounted 10 feet above the earth, and this version of the antenna is made out of 100% horizontal wires.&nbsp; Also, the radiation pattern that is shown is at an angle of 59 degrees above the horizon.&nbsp; There are two reason this angle is what has been shown.&nbsp; One, it is the default angle that the modeling software used, which happens to be where the antenna&#039;s peak total gain happens to be.&nbsp; And two, it is able to show where both the vertical and horizontal components in one screenshot, so there is no confusion that the modeling software is showing that this modeling software is showing both polarizations being radiated.Also, the conventions for these images.&nbsp; The orientation, the Y axis, or from our pints of view up and down, will always be in line with the vehicle facing its front and back.&nbsp; The X axis is the same vehicle, but the left and right sides.&nbsp; This is in conjunction with how the pictures above show how this antenna is mounted to a vehicle.[photo=large]6732[/photo]The green line is the total combined gain, the red line is horizontal gain, and the blue line is vertical gain.This is a test model that shows, again, that this antenna is in fact producing vertically polarized radiation.So the question is why?&nbsp; I stated above that this model, which is similar to the Super Sinner antenna is made up of 100% horizontal wires.&nbsp; Where is this vertical component coming from?The next step was to check these results with another program, so I made a model with the same dimensions using Mmana-Gal, a mininec based modeling software, and got these results.[photo=large]6731[/photo]In this case, the model that matches what is shown above is on the left.&nbsp; As far as vertical and horizontal polarization, the colors are reversed with this program.&nbsp; I don&#039;t know if there is a way to change the color layout, and this is likely the only model I will use from this program so I will just let it be this time.&nbsp; So while in 4nec2 horizontal polarized gain is shown with a red line, here it is shown with a blue line.&nbsp; The opposite is true for vertical radiation.&nbsp; I should also point out that this software is showing gain at 45 degrees off of the horizon, again the program&#039;s default when running this model.&nbsp; However, while this is a different angle, the result is clear, there is vertical polarized gain present.So what does this mean.&nbsp; These programs use two different implementations of what is called the &quot;Method of Moments&quot; or MOM.&nbsp; Because of this, as both show a vertical component, it is very unlikely that this is just a software issue.Because of what I stated above, its likely not a software error.&nbsp; So, where does this vertically polarized gain come from?One thought I had was that the earth might play a part, any while I said I didn&#039;t think it was, it was easy enough to look into, so here I am going to model the antenna in frees-space to rule out the effects of the earth.[photo=large]6730[/photo]Here we see a free-space model of the antenna, again at 59 degrees above the horizon, just like the initial test model above.&nbsp; And here we also see that the vertical component is still present.&nbsp; This rules out the earth below the antenna being the cause of said vertically polarized radiation..That is all I have for now, from here I will try changing the model layout in various ways to see what happens.&nbsp; That, however, will have to wait until I have more time.The DB</blockquote>

[QUOTE="The DB, post: 777774, member: 21346"] So, as no one else had anything to add, I will show some of my initial results here. The first image is created with 4nec2. It is looking at the radiation pattern on the horizontal plane, or like you are looking down on it from above. The antenna was mounted 10 feet above the earth, and this version of the antenna is made out of 100% horizontal wires. Also, the radiation pattern that is shown is at an angle of 59 degrees above the horizon. There are two reason this angle is what has been shown. One, it is the default angle that the modeling software used, which happens to be where the antenna's peak total gain happens to be. And two, it is able to show where both the vertical and horizontal components in one screenshot, so there is no confusion that the modeling software is showing that this modeling software is showing both polarizations being radiated. Also, the conventions for these images. The orientation, the Y axis, or from our pints of view up and down, will always be in line with the vehicle facing its front and back. The X axis is the same vehicle, but the left and right sides. This is in conjunction with how the pictures above show how this antenna is mounted to a vehicle. [photo=large]6732[/photo] The green line is the total combined gain, the red line is horizontal gain, and the blue line is vertical gain. This is a test model that shows, again, that this antenna is in fact producing vertically polarized radiation. So the question is why? I stated above that this model, which is similar to the Super Sinner antenna is made up of 100% horizontal wires. Where is this vertical component coming from? The next step was to check these results with another program, so I made a model with the same dimensions using Mmana-Gal, a mininec based modeling software, and got these results. [photo=large]6731[/photo] In this case, the model that matches what is shown above is on the left. As far as vertical and horizontal polarization, the colors are reversed with this program. I don't know if there is a way to change the color layout, and this is likely the only model I will use from this program so I will just let it be this time. So while in 4nec2 horizontal polarized gain is shown with a red line, here it is shown with a blue line. The opposite is true for vertical radiation. I should also point out that this software is showing gain at 45 degrees off of the horizon, again the program's default when running this model. However, while this is a different angle, the result is clear, there is vertical polarized gain present. So what does this mean. These programs use two different implementations of what is called the "Method of Moments" or MOM. Because of this, as both show a vertical component, it is very unlikely that this is just a software issue. Because of what I stated above, its likely not a software error. So, where does this vertically polarized gain come from? One thought I had was that the earth might play a part, any while I said I didn't think it was, it was easy enough to look into, so here I am going to model the antenna in frees-space to rule out the effects of the earth. [photo=large]6730[/photo] Here we see a free-space model of the antenna, again at 59 degrees above the horizon, just like the initial test model above. And here we also see that the vertical component is still present. This rules out the earth below the antenna being the cause of said vertically polarized radiation.. That is all I have for now, from here I will try changing the model layout in various ways to see what happens. That, however, will have to wait until I have more time. The DB [/QUOTE]

Top Bottom