eddie,
i meant the physical distance between the two elements or current maximas, thats set by the length of the insulator and phasing section,
we have talked about the length ratios before, the vector has dissimilar tube diameters, a tapered monopole that starts out at 1-1/2" down to 1/4"
and a tapered sleeve of 3 or 4 radials topped with a hoop,
the number and proximity of the radials to the monopole raise resonant frequency of both monopole and radial,
i don't know how you compare that to the bottom fed open sleeve using a pair of parallel untapered elements with regards element length other than the tapered elements will be physicaly a little longer for the same resonant frequency, the transmissionline mode impedance will also be different with the different tube diameter ratios even if you used the same spacing,
imagine that the electrical length of the radials is 90" or 106" plus at least half the distance between two radials around the hoop minus the proximity effect,
the patent talked about the hoop shortening the radials while maintaining the same basic electrical length,
since adding the hoop physically shortens the transmissionline length i assume the patent is talking about the electrical length of the radials and not the elecrical length of the transmissionline formed by them,
without the hoop the radials in proximity to the monopole would have to be longer than 106",
if thats the case then the 3.2:1 ratio may hold true for the sigma design,
our stock old vectors were over 31ft and imho too long,
the 4:1 and higher ratios are where the central monopole is 1/2wave multiples and antenna mode impedance is too high to allow much curent to flow the the portion of monopole above the sleeve
