[TowerTalk] Vertical dipoles

[Jim Brown]

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