Modeling and DXpedition experience for verticals near the the tide line
with 2 elevated radials show the gain towards the water is as much as
6.5dbi peak at few degree elevation angle. The pattern is almost a half
circle.
The modeled "backside" pattern is pretty much that one gets from a
vertical over regular ground and of course depends on the ground
properties. I think salt water intrusion can improve those properties
if close to the surface. Modeling this is beyond what NEC4.2 can do,
AFAIK. Perhaps buried or elevated radials in that direction could
improve this. Otherwise the losses, gain, and pattern are pretty much
the same as a vertical over the natural properties of the soil.
Our 160m vertical at H40TT was on a NE-SW running cliff about 12ft above
the water and worked EU better than NA. The "soil" was hard
consolidated coral. There is no ground fresh water on any of the
islands in the Reef Islands group. The modeling done after the
DXpedition agreed with the experience, about a 4db peak gain difference
plus the 20 degree elevation difference.
Modeling agrees with "vertical on pier" experiences. When 1.5
wavelength from the beach with a single shore-ward elevated radial the
pattern is within 1 db of symmetrical.
Grant KZ1W
"Verticals on the Beach, Some Modeling Results", QST June, 2016
On 7/14/2020 02:43, Bill via TowerTalk wrote:
Still assessing antenna options for the new station.
One parcel has about 95 feet of ocean front facing south. Of course the idea of verticals comes to
mind. Here is the issue. . If the vertical is located at the shoreline, I know any vertical will
work like gangbusters in the southern direction. However, will the salt water effect be lessened in the opposite
direction (north) and by how much? And, how much would the directions to the NE and NW be affected.
My gut feeling is to the north it would not be anywhere as good as it is to the
south and to the NW and NE is would be a little better than the north but not
anywhere near as good as to the south. Am I right?
Bill K4XS/KH7XS/ V31XX (soon)
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