'Doc, you're right, my words do not describe the idea very well. I think about this issue in terms of capacitance and inductance, but in this case I tried to describe my thinking in terms using shorter and longer instead, and I got the Idea #2 all corn'fused and illogical. I made an edit to the original post to ignore Idea #2.
The AP beam seems to always get high marks from users, and it is a pretty complicated device both in construction and function. So I'm surprised that we get so many good reports on the beam. When the issue about the transforming harness is discussed, it often sounds like a discussion on: "...I was fooling my SWR meter when I changed my coax and made it longer or shorter."
Starduster, the APB supplies the material for the top element of the driven element as follows: 1/2" x 48" and mark off 7" to be inserted into the bottom section 5/8" x 36" = 77" total. I figure that this element is electrically about 79" long overall if we consider the mounting bracket and plate that it sits on which I figure to be about 2" additional.
However, when I made my Top One into a full 1/4 wave radiator on top, I got it resonant @ 27.205 with an 87.5" radiator. So, I don't see how the beam can work with resonance at 27.205 while the top radiator is only 79" long unless, like I suggested, the director and reflector make the difference.
Will you be using an analyzer when you build your beam? I sure would be interested to know what kind of numbers you are seeing at resonance and at the ends of your <1.5:1 and your <2:1 bandwidths.
You will figure it out when you get your APB up and working I'm sure, so keep us posted on your progress.
