[Antennaware] EZNEC Element Correction Factors

[Gedas]

Hi Charlie, thanks for that information.  Funny you should mention, 
someplace I still have all my old 5-1/4" YO, and MN, and WO etc diskettes.

Since the time I posted my questions I have been looking around on the net 
and am now more confused than ever.  It seems the elements should get longer 
if passed through the boom if they are insulated.  I have no idea why the 
one 2M9 model I have shows elements slightly shorter than those in the M2 
manual.  Maybe someone will come to my rescue here.  73
Gedas, W8BYA

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

----- Original Message ----- 
From: "Charlie Ocker" <N9CO at aol.com>
To: <antennaware at contesting.com>
Sent: Tuesday, January 21, 2014 7:18 PM
Subject: Re: [Antennaware] EZNEC Element Correction Factors


> Hi Gedas,
>
> I am not familiar with this correction technique, so I cannot comment, but 
> I do have experience with the boom *and* element clamp correction method 
> employed in K6STI's Yagi Optimizer (YO) code.  It puts a "dummy" element 
> of a certain length and diameter at the boom end of the element.
>
> Subsequent modelling in EZNEC (including the "dummy" element) reveals a 
> very tight correlation, and better still, building the Yagi to the 
> dimensions given by YO (and verified in EZNEC) results in an antenna that 
> appears to meet all the initial design criteria.
>
> I have done this for a number of Yagi's designs ranging from 6m to 20m.
>
> 73,
> Charlie  N9CO
>
> On 1/21/2014 11:57 AM, Gedas wrote:
>> Hello group.  I am trying to model a M2 2M9 for a friend for his rover
>> use. I have an EZNEC model (not sure where I got it from) for the M2
>> 2M12.  By looking at the PDF manual for the 2M12 and comparing it to the
>> EZNEC model I have on hand, I can see that an element length correction
>> factor has been applied to each element.  I.e., each element is slightly
>> shorter in the model than in real life because the element passes
>> through the boom.
>>
>> I am puzzled a bit as I noticed that the correction factor varies
>> slightly from one element to another.  One element is approx 99.65% of
>> the PDF manual length, another element showed up as 99.21%, while a 3rd
>> element showed up as 99.38 %.  They are actually all a little different
>> from each other.
>>
>> I guess I have two questions; is my model of the 2M12 wrong because it
>> shows variable correction factors?  And, if the correction factor is
>> required to be constant, what should that factor be so I can generate
>> valid models for these antennas?
>>
>> Ok, maybe one more question, what should the correction factor be for CC
>> antennas like the 17B2 where the elements are mounted with a clamp on
>> top of the boom?  Thank you.
>>
>> 73, Gedas, W8BYA
>>
>> Gallery at http://w8bya.com
>> Light travels faster than sound....
>> This is why some people appear bright until you hear them speak.
>>
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