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
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Topband reflector - topband@contesting.com
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