On 1/15/2020 9:55 AM, Roger Parsons via Topband wrote:
There is very little pattern difference between a purely horizontal dipole and
an inverted V provided that the angle of the V is not too acute. A horizontal
dipole 5/8 wavelength high has predominantly low angle radiation.
But there IS a difference in efficiency that looking ONLY at the pattern
misses. To understand this, take a look at
http://k9yc.com/VertOrHorizontal-Slides.pdf
starting around slide #18, which plots the pattern of an 80M dipole as
it's height is varied ON THE SAME AXES, and the following slide, which
picks points off of those curves to show gain vs height at vertical
angles of 5, 10, 15, 20, and 70 degrees. Slide #19 clearly shows that
gain at low angles increases with mounting height. To apply these data
to 160M, simply multiply height by 2.
There is, of course, also the matter of how horizontally and vertically
polarized waves propagate, and how they are affected by nearby earth.
Vertically polarized waves encounter a very strong loss component from
poor soil conductivity, while horizontally polarized waves are almost
unaffected.
73, Jim K9YC
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