[Antennaware] EZNEC how to choose number of segments

[Aage Halvorsen]

Don't forget that the vertical pipe if metal is part of the antenna 
and/or the coax as well.

Simulation might show that you have to insert some common mode choke(s) 
in the coax if using a non conducting pipe/tube to put your antenna on. 
If metal is used you might have to adjust the length of the pipe for 
best result on the band designed for.

This problem is mostly forgotten as the vertical pipe is mostly ignored 
for the simulation, as is the cable.

73's

Aage-LA4ZH

On 13.07.2019 15:33, Guy Olinger K2AV wrote:
> This thread is for Dave. So I'd rather not hijack this thread for a
> separate and likely lengthy topic. So I will not comment here. Please start
> a separate thread with a separate subject that includes "EZNEC
> auto-segmentation". If you ever want yourself or others to be able to find
> the discussion in the archives, a separate and pertinent subject will be
> mandatory.
>
> Thanks,
>
> Guy K2AV, Antennaware Admin
>
> On Fri, Jul 12, 2019 at 2:00 PM Mike Waters <mikewate at gmail.com> wrote:
>
>> Hello Guy,
>>
>> It sound like you are saying that EZNEC's auto-seg feature should be
>> overridden in some cases. I am all ears, sir! :-)
>>
>> The feature has *conservative* and *minimum recommended*, as you know.
>> Are there cases when even *conservative* is not good enough?
>>
>> 73, Mike
>> www.w0btu.com
>>
>> On Fri, Jul 12, 2019, 8:17 AM Guy Olinger K2AV <k2av.guy at gmail.com> 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> 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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