Topband: Comparison

[Mark Beckwith]

Kevin,

I have modeled Ts and Ls and quarter wave verticals.  When you model them 
against the same ground they are all pretty close to each other (like within 
a db or two).  I like the T because the pattern is round and the takeoff 
angle is overall lower than the L.  The L gets not symmetrical as a function 
of where the horizontal part goes and how high it is, and the takeoff angle 
is different in different directions as a result of the same factors.

What I have noticed is that getting the feedpoint off the ground had the 
biggest effect (on the models).  I could have a 130 foot vertical if I fed 
it at ground level, but I chose to elevate the feedpoint 40 feet and have a 
90 foot T instead because it modeled better with fewer, easier to install 
radials (the four radials slope down to about face height).  (My ground is 
sand and rock with lots of wildlife).  I guess that makes my antenna more of 
a "groundplane" than a "vertical."  On the air it works real good.

See you in the Stew.

Mark, N5OT