It is well known by DXpeditioners and an EZNEC analysis demonstrates
that verticals within 1 wavelength of the sea have greatly enhanced gain
at low elevation angles in the seaward direction. There is no need for
the antenna to be over water for that benefit. In the opposite
direction the pattern is that of a vertical over whatever that direction
ground properties are.
The conductivity of sea water saturated sand is closer to 1 S/m and
seawater is usually modeled as 4 S/m.
See my paper "Verticals on the Beach - Some Modeling Results" in QST
June 2016 and Al Christman K3LC "Verticals by the Sea" series in NCJ 2005.
A conductive plate football field size will reduce ground losses in its
direction if connected as "radials". It will have essentially no
influence on the far field elevation pattern.
Grant KZ1W
........snip.....
The soil surface conductivity is vey low. If you think about a cooper
plate large as a football field or salt water, a vertical near it will
perform very poor, it only will perform well "on it" , connect with the
plate and on top of the plate. That's way AA7JV vertical antennas works
so well, George install them inside the water. Near the salt water does
not work. Conductivity wet ground (beach) is 0.02, sea water 5. The same
with radials and mesh wire if you don't connect it, it does not work!
73's N4IS JC
Why would bonding the added matting be required if it is laid over or
beneath an existing radial field? It reduces ground losses regardless.
Peter
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Ray,
N6VR
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