Not necessarily. It is best practices to get all of the segments to be the same size, but in many cases, one of them being specifically a radial hub, and cases where you have limited numbers of segments to work with, that may not be possible. That being said, there are very specific instances where said segments have to line up perfectly.
Actually, one way to correct an AGT issue that Marconi referred to is to adjust the length of some of the segments. As long as none of the segments on the model get to be longer than a certain % of a wavelength, then there is no need to worry, as long as the AGT checks out.
I once thought that free space models were not relevant, but that was years ago. As with most of my views on antennas and how they work, my views have changed drastically over the years, and in some ways said views are still changing, perhaps evolving would be a better word here? Today I would tell you that you can learn more about how an antenna actually works and where it is actually trying to put its RF from a free space model than what we can see with a model over an earth.
I do tend to stay away from posting said models because there are a lot of people that, similar to what you said will try and tell you that freespace "does not exist in the real world" and such it is useless. This tells me all I need to know about what said person knows about antenna modeling. This is one of those beliefs that some people will believe to the core even with irrefutable proof to the contrary, so its better to let them believe what they want. I find it especially funny when this comes from someone who has no actual experience modeling... What can you do? There are a lot of things in this hobby that even very knowledgeable people believe in fervently even though they haven't ever seen any evidence, much less proof... At least you, Bob, and some others actually try to get to the bottom of things.
The DB
