Topband: Further discussions on EWEs

[Tom W8JI]

> Tom, et al: is there data that nail down the horizontal wire to vertical 
> wire ratio?  I see in that write up by wa1on mention of 2.25:1 h to v 
> but...is that some rule that can't be violated or.../
>
> For instance, assuming a vertical section height of 10' I could run a 
> longer horizontal section but don't know if that gains me anything.

I can't imagine why there would be some set rule or guideline, except with 
many qualifications. I'm sure there is some general range of lengths vs. 
height for various configurations. The ideal shape would be rectangular with 
source and load centered in the shorter vertical wires, which is the 
equivalent of a base-fed  EWE over perfect ground.

The horizontal part or component of the antenna works best when it behaves 
most like a transmission line with a velocity factor of unity (ideally 
faster than light). The longer it is and the wider it is spaced, and the 
poorer the earth below the antenna, the more the system responds to unwanted 
signals in the horizontal mode.

The vertical component of the antenna wires acts like two verticals, and is 
the desired signal response.

You can see the obvious conflicts. If the vertical section is taller, 
horizontal spacing is wider and that response increases. If the length along 
earth is longer, the verticals are separated more and this increases 
sensitivity of the verticals (until they are 1/4 wave apart) but it also 
makes undesired horizontal sensitivity increase.

There are a half dozen things that can make one thing better while making 
other things worse. Everything, including characteristics of the earth and 
things around the antenna, would interact.

If you really wanted to optimize an antenna like this, you would have to 
make it two short verticals that are phased. After all, that is all the 
antenna actually is.

73 Tom