Now this is something I had not seen before, but may have thought about. Does anyone know some approximate measurements for this antenna? The one I'm most interested in is how long is the entire antenna? If it is noticeably longer than the Sigma, Dave and I had the same idea about how to maximize the effectiveness of the cone. If this is what I think it is, I'll explain in detail what the differences are and why it is showing more gain in EZNEC.View attachment 35605 This one?
Oh yes, see why they call it bird cage now. Plenty of roosting places, and can conveniently be used by Raptors needing a nest.
I have seen several of Daves creations, most were elaborate affairs compared to your average homebrew antenna & this one reminds me of those,
its claiming full wave but that could be 3/4wave monopole + 1/4wave radial sleeve,
looking at proportions if it is a full wave monopole the sleeve would have to be much longer than 1/4wave,
for a long time I believed that the longer monopole increases unbalance at the top of the cone because its not level with the high impedance point on the monopole 1/2wave from the tip,
which transmission-line theory tells us will increase radiation from the outside of the sleeve,
Lockdown means i can't get started on my sigma with full length sleeve & 1/4wave radials,
probably make a hub so i can add/remove them to see if they give the sigma the ground-plane it needs according to some respected people,
are radials the key to making radiation from the cone compress the pattern,
I will find out,
i can also move the fiberglass isolator from the base of antenna to 1/4wave below the antenna to see if having that part of the mast radiate is of benefit or detrimental.
View attachment 35605 This one?
This was pulled off of Facebook from DavemadeNJ
711, can you give us a source for the jpeg files you added to your original post #2, that were below this image?
Bob says he heard this antenna is a full wavelength tall. Can you confirm that information or give us a link to the source?
Yes Eddie that's what im getting at, 1/4wave cone & 3/4wave monopole puts the hoop close 1/2wave from the tip where current is lowest & voltage is highest,
pictures can be misleading as we have seen in the past,
the cone looks to be more than 1/2 the length of the radiator above it, could it be a full wave radiator with 3/8wave cone,
VORTEX use a 3/8wave cone.