[Antennaware] EZNEC how to choose number of segments

[David Gould]

Hi Guy,

Thanks for quick reply,

If I just start with the 20m vertical.  It is 38mm tubing with the base 
10m off the ground, the source is in the first (bottom) segment.  Then 
there are two tuned 1/4 wave 2mm wire radials for 20m connected to the 
bottom of the vertical and drooping down at 45degrees.

Is the ground type that important when it is so far off the ground?  For 
reference it is real/MININEC medium - would an alternative be better?

Does that give you what you need?

73,

Dave G3UEG



On 12/07/2019 14:16, Guy Olinger K2AV wrote:
> Hi Dave,
>
> What are you using for the vertical's counterpoise? What are you using 
> for the the ground type? Where is your source placed?
>
> These are essential to answer your question.
>
> 73, Guy
>
> On Fri, Jul 12, 2019 at 8:02 AM David Gould <dave at g3ueg.co.uk 
> <mailto:dave at g3ueg.co.uk>> wrote:
>
>     Most of my modelling has been with wire antennas but now I am
>     modelling
>     some verticals with elements having diameters of between 38mm and
>     25mm
>     for 20m and 40m (and using drooping elevated radials made of wire)
>
>     I usually use around 9 or 11 segments for a 1/4 wave element. I
>     noticed
>     that when I changed the number of segments the results for things
>     like
>     feed impedance changed quite dramatically.
>
>     Are there some guidelines for the number of segments for a 1/4 wave
>     straight wire element?
>
>     How is the choice of segment length affected by the diameter of the
>     element tubing?  Is there a limit on the ratio of segment length to
>     segment diameter?
>
>     73,
>
>     Dave G3UEG
>
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