On Tue, 17 Nov 2009 23:29:19 -0500, Ian Hill - K8MM wrote:
>Vertical dipoles are good low band antennas.
Hold on a minute -- I think we are talking about very different
antennas. :) I have a top-loaded vertical (some would call it a
monopole) for 160M that works a treat, but it is not a DIPOLE. It's
an 86 ft vertical wire with a horizontal piece on top to bring it to
resonance, and it works against radials (to carry the current and
provide a path for the fields).
A vertical half wave DIPOLE behaves VERY differently from a vertical
monopole. The top half and bottom half of a vertical dipole both
radiate, and together form a complete antenna. The vertical part of
a monopole needs radials (or a counterpoise) to form a complete
antenna, and to the extent that they are symmetrical, the radiation
from the radials cancells in the far field.
73,
Jim K9YC
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