On 3/23/2011 3:55 PM, Richard Fry wrote:
A few years ago there was some discussion on r.r.a.a. about helically-
wound, normal-mode monopoles, and the rather common expectation that
they had higher gain than a linear monopole of the same physical
height (and with other things equal).

A recent NEC-2 analysis of this topic might be of interest:
http://i62.photobucket.com/albums/h8...r_Monopole.gif
.

Also this link to a page from John Kraus' ANTENNAS FOR ALL
APPLICATIONS, 3rd Edition: http://i62.photobucket.com/albums/h8...ndVertical.gif
.

//

Somehow, I think there is a difference. I think that they are being
shown to be the same in the computer model is not valid in the real
world. That said, in real world use, the differences do seem to be
insignificant.

And, that said, I use a helical wound, half-wave electrical length -
quarter-wave physical length, monopole in lieu of a 1/4 wave ELECTRICAL
length and physical length antenna. And, in personal experience, this
DOES provide increased performance over the 1/4 wave.

In most real world restrictions, the helical wound versions always are
an advantage in real world physical size ...

Regards,
JS