Certainly near by terrain affects your station antenna pattern, in the
case of obscuring a clear low angle of take off. That is a near field
effect. However beyond the Fresnel Zone, (3 to 5 wavelengths at a band
you are using), there can be great effects caused by land at that
distance. And of course, there is not much you can do to enhance the
reflectivity there. Things like metal ore deposits have been reported
to affect signals at some bands.
A HF station located at the edge of a drop off often sees a signal
advantage in the downslope direction is another observation that has
been reported.
About all you can do for things like dense foliage near your station
property, is to raise the antenna higher than the grove of trees; or try
to see if a vertical antenna works better than a horizontal at your
location.
Look up the writings on HF propagation to learn more detail.
Stuart Rohre
K5KVH
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