[Antennaware] EZNEC Element Correction Factors
Guy Olinger K2AV
olinger at bellsouth.net
Wed Jan 22 00:00:35 EST 2014
Perhaps you can talk to someone at M2.
On Tue, Jan 21, 2014 at 8:30 PM, Gedas <w8bya at mchsi.com> wrote:
> 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.
>> 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.
>>> Antennaware mailing list
>>> Antennaware at contesting.com
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