[TowerTalk] All the right angles.

[alsopb]

Guys,

I had been looking around for some source of info which gives the
arrival angles for DX stations.  

It turns out this information is available in a very convenient form
from the ARRL website.  The "statistical elevation" files when
downloaded interface with either YTAD (a public domain program
allowing one to determine the impact of ground terrain on your
pattern) or YT which is bundled with the ARRL antenna handbook.  

http://www.arrl.org/notes/antbook/yt-files.html

What one can get when running either program is a plot of your antenna
pattern over the actual terrain with *'s showing the percentage of
time signals from the part of the world of interest at each angle for
someplace close to your QTH.

One can superimpose up to 3 antenna designs (stacks etc) or a flat
terrain profile and quickly assess what's going on.  You want to know
the impact of that hill a half mile away? It's there.  It's really
neat.

Both of these programs require inputing the terrain info in the
direction of interest.
I found that the TOPO-2 program from DELORME can be used to get this
information.  It isn't in nice tabular output form but can produce a
printable plot of elevation versus distance which you can pull numbers
off of.

How did my QTH do?  It depended upon frequency and path.  Actual
terrain seemed somewhat better to Asia than flat ground.  Europe was a
wash.  For the normal contest situation with 80-90% EU and 10% Asia,
the results were at least as good as, or slightly better than, flat
ground.  At least it wasn't any worse. 

If you do this look at calcs using the provided KM1H or K5ZD terrains
and see how you compare.

Interesting stuff.

73 de Brian/K3KO

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