Homer, your suggestion here that I was looking for improvement is not what I was trying to demonstrate. It is obvious that I see the SD'r model and the results differently than you guys.
Keep in mind that I described my SD'r at 36' feet high, because that is the height of the model I used for this project. I wanted to see if what FC told me could be true, that his SD'r positioned upside down would radiate the maximum signal down below the horizon...as he noted from the side of his mountain location. He said it help him and I believed he probably saw what he saw, but I didn't agree with the idea. This is the reason I modeled the idea to see what Eznec might predict.
If you will consider for a minute where the feed point is on a SD'r, you will see that the antenna is balanced and center fed, and that flipping it over at the feed point changes nothing relative to the current node. Again the feed point is at 36' feet, and that is unlike what would happen if I flipped over a 5/8 or an end fed 1/2 wave antenna and set them at the same feed point height.
Because the SD'r is balanced and center fed is why we see these models showing no change in height, gain, angle, or pattern when we flip it upside down. I'll admit I did not know the details for why, until I did this model project, but I took exception to FC's idea back then none-the-less. That was because in my thiniking that was not what I would have expected, and that was base on what I had in my minds eye for a 1/2 wave dipole pattern looking like a circle or 1/2 a circle.
You guys thinking here seems to be stuck on considering a 5/8 wave only, or in your case Homer, your end fed 1/2 wave. In Shockwave's case he is thinking and talking about his Vector being flipped over. Each of you is forgetting that FC and I were talking about a center fed Starduster. These other antennas did no come up in my discussion with FC.
Again, I only did my 5/8 wave model after SW mentioned his Vector. I did a 5/8 wave model so I could see if there was any difference. I saw a noticeable difference so I posted same showing the difference between the SD'r and the unbalanced 5/8 wave antenna...you're all focusing on.
You guys are correct, there will be differences regarding these other unbalanced antenna designs. The patterns, gain, and angle would change on flipping, just as my 5/8 wave model shows.