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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