On Fri, 20 Mar 2009 11:29:29 -0400, Scott McClements wrote:
>pecifically, would a 3D trace over a wider angle produce better
>results?
As an EE, I learned long ago that I will learn far more from
finding many points on any curve than only one or two. It's far
easier to understand the elephant with observations through many
widely spaced pinholes. I ran HFTA over every 5 degrees of
azimuth. Although my terrain is rather complex, I did NOT see the
sort of inconsistency that Steve (N2IC) described.
>Why is it just 2D?
One very good reason is the level of detail in the avaiable
terrain data, and how that relates to the wavelengths involved.
Another equally good one is the nature and complexity of the math.
It makes no sense to use a more complex calculation if the
underlying data has less detail than the calculation. HFTA models
the interaction of horizontally polarized waves with the earth,
especially diffraction.
I work in pro audio, where we must do a lot of work to understand
how sound waves interact with enclosed spaces (like concert halls,
theaters, etc), and I have done a LOT ofr complex FFT analysis of
that sort of thing. N6BV's recent post in this thread makes
perfect sense to me.
73,
Jim Brown K9YC
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