On 10/27/2025 11:53 AM, Rob Atkinson wrote:
I don't want to take away from the original topic but this raises an
interesting question: If I have a horizontal antenna such as some
sort of dipole (a REAL dipole and not the thing the Ask Dave guy
thinks is a dipole in QST) and it's over a ground screen, will the
screen work better if it is tied into the station ground, or left
floating?
I answered that question in the write-ups of the studies I wrote for NCJ
about ten years ago. The ARRL graphics department said it was too
demanding of their time to publish the extensive graphs that clearly
showed the mechanism, so it never ran.
In this thread, I restated those results -- the effectiveness
(efficiency and vertical pattern) vertical antennas are strongly
affected by soil quality and height of the feedpoint, while horizontal
antennas are not affected by ground quality, but are strongly affected
by mounting height.
Horizontal antennas care about "ground" quality only for NVIS, where the
soil is acting as a reflector, and the optimum height for NVIS is 1/4
wave, which causes the reflection to be in phase with the antenna. For a
higher antenna, the reflection could be provided by a a horizontal wire
of suitable length.
Other than that, it doesn't matter what is on the ground under
horizontal antenna, it only matters that it's horizontal, so produces a
horizontally polarized wavefront.
How many times must all of this be repeated?
73, Jim K9YC
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