Dave Platt wrote:

I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any
other antenna with a single resonance.

It has "minimal" reactance at resonance and is highly reactive
elsewhere.


It looks to me as if this is a member of the "Super C" antenna...
short, relatively low radiation resistance, and a lot of top-loading
capacitance.

There's an article or two in one of the early ARRL Antenna Compendium
collections (#1 or #2) which analyzes the "Super C" approach, compared
to a short vertical with a more traditional capacity hat made of
straight wires. The analysis seemed to add up to "Probably not worth
the trouble and money", as a similar efficiency can be achieved more
easily and less expensively with the traditional approach. There's a
*lot* of metal in the MRA, and at the price of aluminum this month I
doubt it's a project I'd start.

Yea, but put in on a rotator and add some horses and it could double as
a merry-go-round. :-)

ac6xg