On 8/26/2020 10:07 AM, David Gilbert wrote:
Radiation angle for a vertical antenna is much more a function of the
ground conductivity out several wavelengths than it has to do with the
current balance in the radials.
Right, but N6LF has shown that current balance in radials, especially
elevated ones, minimizes ground losses. Yes, elevated radials can be
modeled in less capable versions of NEC. All of this is addressed in my
slides.
In all cases, the model must use soil conductivity representative of the
QTH. This is selected from a menu. Soil conductivity affects us two
ways. First, losses underneath the antenna. Better radial/counterpoise
systems can reduce this a lot. Second, loss in the far field, over which
we have no control, and those losses can vary a lot if soil varies a lot
in different directions. For example, a vertical on a beach has much
less far field loss, and much more energy at low angles, in the
direction of the water and much more far field loss and higher angle
energy than in directions over land.
73, Jim K9YC
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