Pete Smith N4ZR wrote:
> What MicroDEM does, if used according to the instructions, is to draw
>radials from the antenna location out some 3-4 miles, which are
>readable by HFTA as .pro profiles. These radials are simply the
>electronic equivalent of drawing pencil lines on a topographic map and
>entering the elevation at, say, 10-meter intervals
The database method will produce a table with rounded, uniform numbers
in the distance column and interpolated heights; but when using a local
topographic map it's probably easier to do it a different way.
Lay out your ruler along the desired beam heading, with zero at the
antenna location, and then measure where each contour line crosses the
scale. That creates a table with odd, variable steps in the distance
column but uniform round numbers in the height column. HFTA doesn't mind
either way.
You may have to do some local editing anyhow. Since SRTM used microwave
radar, it reports dense treetops as "ground level"... which is not a
mistake an oldtime surveyor on his horse would have made. By all means
use your own eyes and local knowledge, and edit the height data
accordingly.
--
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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