Topband: inveted L 3/8

[Tom Rauch]

> shows a perfect ground system with the 1/4.  I always thought the
> angle would go down until the antenna lenght would reach 5/8 wave and
> then go back up. I would think that still would work on bent vertical
> antennas from 1/4 up to 5/8 wave.  Anyway back when chasing DX on 160
> was tough in the 60s and 70s loran and power limits of about 100 watts
> out. the longer inverted Ls were outdoing the bent 1/4 verticals. 
> talk to some of the old timers on this.  

While almost anything will radiate...with a short vertical section 
Inverted L making the antenna longer decreases the useful low-angle 
radiation. It also does not necessarily decrease ground losses enough 
to overcome the reduction in useful low angle radiation.

The optimum loading for an Inverted L (for DX) would place maximum 
current somewhere near the middle of the vertical section, not at the 
top or bottom. That way the ampere/feet of the vertical section is 
highest, and radiation resistance (by IRE definition, not feedpoint 
resistance) is highest.

A true vertical is different, and does have a lower wave angle as 
height is increased up to about .6WL. However, it is NOT the lowest 
takeoff angle that is important. It is the maximum field strength at 
low angles that an antenna provides that matters most in most 
cases.73, Tom W8JI
W8JI@contesting.com