Dan Arney wrote:
> I am ready to do my 3 ele 40M on a 54' X 4" boom. I am also doing a 2 ele
> 75M. The 40M eles are KLM linear loaded and the 75M uses Create CD-78
> rotatable dipoles, it is supposed to be on a 24'6" boom. I would like to
> interface them on one boom. Will your software model that? Or is it just a
> put up the 40M and then the 75M then fit and play with it. It would be nice
> if a program could get it somewhere in the ballpark Hi.
> Any info you can provide would be greatly appreciated
Hi Dan,OUCH! Now there is a question from HELL!
Maybe you get the new award!
First off, YagiStress does not perform electrical modeling. It does provide a
W2PV electrical length to allow you to keep an element at the same resonant
frequency when you are changing it physically. I'm sure there are several more
qualified and more experienced electrical modelers than can help you with this
interlaced configuration.
As far as mechanically analyzing your project, the Create CD-78 elements can be
pretty accurately modeled with YS. The capacity hats need special attention, but
can be done.
The KLM elements are impossible. This is caused by the additional projected
areas created by the linear loading tubes. They add area and weight at the
locations where they are joined to the main element by the spacers and shorting
straps, but do not add any significant structure. Not all of the required values
for area, moment of inertia, and section radius can be achieved to get accurate
stress values. I always wondered how they did the mechanical design. It's not
easy to do it properly.
This can be done properly with an FEA program because the user can assign any
section properties and any loads to any given piece of the model. This requires
the user to come up with everything on his own. Not to neat for a program, like
YS that's supposed to make the job as painless as possible!
YS can analyze the boom and other antenna properties, after you provide some
fake KLM elements that have the same weight and area. I can help guide you in
this exercise.
Good luck with the project!
73, Kurt
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