Topband: Fwd: radals fer 160m vertcal

[Dan Zimmerman N3OX]

> So, until one of the authors writes code to join the two processes, we're
> left with analyzing the two graphs independently (as shown by Richard).  I
> imagine that the code needed is not a trivial task to write and unless
> there's a high demand for it, that may never happen.  Even so, the surface
> wave calculator is still a great tool.  We just need to know that the
> far-field vertical elevation profile is not enough to get an accurate result
> near the horizon with base-fed vertical antenna

One workaround is to use some other software for plotting.  I've used
GNU Octave and EZNEC's near field table to make plots of the total
field at finite distances:

http://n3ox.net/files/nfpatt.png

I've intended to put some "Octave antenna plot recipes" on my website
but haven't had time for it yet.  But I'm not exactly sure  composite
patterns like those plotted above are of major concern...

The far field pattern will  accurately capture what is going to reach
the ionosphere.  A surface wave table will accurately capture your
groundwave range.   If you were to try to do a plot as far as the
distance to the ionosphere at a low angle, the above plot would be
misleading because the earth has dropped away significantly, taking
the strongest part of the earth-hugging surface wave with it....

It's always good to have different ways of looking at things but I'm
not entirely sure what the above field plot is good for unless you've
got your balloons or rockets or helicopter out and you're trying to
actually measure the whole elevation pattern a few wavelengths from
your 160m vertical to compare with calculations.

73,
Dan