Back when N6BT owned Force12 they manufactured Sigma vertical dipoles. It
was a sideways H shape fed in the middle and it had handmade wire inductors
to reduce the length. I always thought that was a pretty good antenna for
its size and ease of installation.
John KK9A
Jack Brindle W6FB wrote:
One very pertinent thing that has not been mentioned is N6BT's development
of Vertical Open Ring (VOR) antennas. In this design the "ground wire" is
actually a 1/4 wave ring that wraps around the base of the antenna. The
vertical is up off the ground some distance (less than 1/4 wave, perhaps 1/8
wave). The antenna is described in the latest (4th) edition of Tom's book
"Array of Light". He has spoken of it in quite a few presentations that are
now available on Youtube, including an NCCC meeting earlier this year.
Definitely worth a view.
It is also interesting that the November issue of QST shows an antenna of
this design, by G4UNA. Either the author re-invented Tom's work, or failed
to give him credit, but this article also demonstrates the VOR concept.
Essentially the radial consists of a 1/4 wave piece of wire that extends out
from the base at an angle, then forms a partial square around the antenna.
The wire is terminated before it touches itself, thus the square is not
completed. In Tom's experiments he showed that the wire might make up only
three sides of the square and perform just as well as if it extends on the
fourth side.
By the way, his book is also a gold mine for ideas about raised radial
verticals. They perform incredibly well at the beach - he still holds
several QRP records from the Caribbean for QRP contests using these
antennas. Contemporary reports show that the gull-wing style of radials
perform very well.
This topic is very well discussed in ON4UN's "Low Band DXing" and slightly
lesser so in the latest ARRL Antenna Book.
Sounds like some experimentation may be in store to see what works best for
the OP.
73,
Jack, W6FB
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