Homer
im surprised because if the sigma is just an efficient elevated 1/2wave the astroplane at the same tip height should not be notably behind imho,
the stock sigma lacks the groundplane of the open sleeve antenna article i made such a fuss about,
it was suggested by more than one source both more knowledgeable than me on antennas that it needs the groundplane in order to do what the open sleeve article says,
a couple of folk have claimed the cone model proves there's very little radiation from the cone,
imho the model of the cone on its own terminated with a dummyload is only showing radiation due to the conductors not been parallel,
transmissionlines don't radiate when terminated with dummyloads regardless of been mismatched or not,
the cone or the stub in a j-pole has high vswr on it & its not balanced with a dummyload,
its unbalanced and that's what causes radiation in transmissionlines & the stub of a j-pole,
im not surprised at all that the terminated cone shows very little radiation,
if you can increase signal as much as Henry's model shows its well worth doing,
the isolator i made for the astroplane will clamp straight to the base of my modified sigma.
