Homer I think highly of the Starduster design.
What does the copper tubing do?
Because the radials attachment at the top of the radials is a plastic material I needed a means of mechanically connecting the four radials that conducted current. That is the purpose of the copper ring - nothing more. I will likely replace it with some aluminum material in order to avoid any potential galvanic activity between the metals.
I think you're right this setup adds a little length, but with such a good match why bother with a fix?
First, I think it prevents me having to cut off more than necessary of my radials. The end sections of each radial is made of fiberglass mobile whips. Also, although it shouldn't matter at 11 meters HF, the topic of symmetry has arisen a time or two. When I consider the
need for the angle of the radials on a 1/4 wave GP to be right in order to set feed point impedance I find myself wanting to keep the radials as near the feed point as I can. If I can close the distance between the top of the radials where the angle begins I can not see whether there would be any harm, and there may be some benefit. As it is now, the top of the radials are more than twice the distance from the SO239 x 3/8-24 connector than the bottom of the vertical. I just want it tighter.
The Merlin uses a similar setup I think, maybe even more so.
I believe you're right about the Merlin having a similar setup. I never actually tried to replicate the Merlin, it just worked out that way. You will notice the two halves of the antenna are equidistant from the SO239 connector.
How does this one compare?
I have had it up just a little while, but so far it is noticeably noisier than the Moxon horizontal beam. That could well be a polarity difference. On the other hand, when the noise level drops it has good receive. I made a few contacts with it today, but skip is unreliable as a test except to say it is useful. Time to test the consistency of the antenna under conditions might say more. I also spoke to some stations locally this evening whose distances ranged from 1/4 mile out to 2 miles, then to 10 miles, and on out to 30 miles. The 30 mile station is due north of me and was pointed west with a 4 element beam horizontally polarized when we first made contact. The contact was solid and clearly readable at both ends*. Naturally, when I went horizontal with the Moxon, and we were pointed at each other it was as if he had moved to town. Nevertheless, it is as good a contact vertical to horizontal as I've ever made at that distance.
The antenna shows promise.
*My 2950 has no bars, not an analog meter. I can not report on S-units.
