[TowerTalk] 80 meter antenna comparison

[Jim Brown]

On Wed, 30 Jan 2008 09:26:33 -0800, Richard (Rick) Karlquist wrote:

>For DX, a dipole at 115 feet is interchangeable with a single 1/4 wave
>vertical in terms of transmitted signal strength. 

I think broad generalizations like this are dangerous.  

I have a 160/80/40 dipole at about 105 ft, and a top-loaded 86 ft 
vertical for 160 and 80. Which is "better" for any given path will 
depend STRONGLY on the vertical angle for propagation between me and the 
DX station at any given time of day, as well as the directional 
properties of the dipole. There are times when the path will be a fairly 
high angle one, in which case the dipole will be better. Often on 40, 
and occasionally on 80, I can work long path to EU. My Beverages 
(pointed long path) almost never hear the long path station, and if they 
do, the level is much below the dipoles. 

Which is better will also be influenced by how the topography near your 
QTH modifies the propagation in any given direction. This topo can 
interact differently with horizontally and vertically polarized waves. 
The propagation from my QTH is strongly influenced (dominated) by a 
ridge to the north and east that essentially kills (by diffracting 
upwards) any radiation below about 4 degrees. This makes is quite tough 
for me to work EU short path, even from antennas that produce a lot of 
low angle radiation. 

73,

Jim K9YC