[TowerTalk] 40 meter vertical ant

[Jim Brown]

On Sun, 11 Feb 2007 22:51:49 -0600, K4SAV wrote:

>If you have two 80 ft 
>trees, you could put up a horizontal dipole that would beat the half 
>sloper and the vertical.

Until I moved to California this spring, I never had a decent antenna, 
let alone two decent antennas. Now that I have some good high dipoles 
and a pretty good vertical, I've learned firsthand that vertical 
directivity is at least as important as horizontal directivity, and 
often more so. 

A broad statement that a dipole will outperform a vertical is a 
generality that is NOT true. On the other hand, it IS true that under 
a given set of propagation conditions, either the vertical or the 
dipole may outperform the other by 10 dB or more. Terrain does not 
allow me to use a 40M vertical effectively, but my experience tells me 
that my 70 ft top-loaded vertical will often blow the pants off of my 
100 ft high dipole on 80 and 160, especially for several hours both 
sides of sunset or sunrise. 

A study of antennas of various height using Dean Straw's HFTA software 
(in the ARRL Antenna Book) can be quite instructive. It was for me. 

73,

Jim Brown K9YC