Hi, Jim.
I did pretty much the same thing for the key azimuth points I was
interested in. I used Delorme's 3D-Topo Maps program (which no longer
works on Windows 8 or 10, by the way). I simply drew a line in the
desired direction and manually read the elevation and distance figures
off the terrain plot. By doing that I was able to pick data points
determined by the change in elevation instead of the change in
distance. So my text files looks more like:
0, 5000
15, 4990
35, 4980
70, 4970
85, 4960
etc (numbers above for illustration only)
instead of:
0, 5000
10, 4993
20, 4987
30, 4982
40, 4978
etc
HFTA simply draws lines between the data points, so in my opinion it
gives more accurate rendering of the terrain profile with a relatively
fixed increment of elevation than with a fixed increment of distance.
It also allows 150 data points to extend out much further unless the
terrain profile is very choppy. In my case here in southern Arizona,
HFTA can recognize the effect of a mountain range some 15 miles distant
so the extra distance from the method I used was useful to me.
73,
Dave AB7E
On 7/16/2016 4:28 PM, Jim Brown wrote:
Gary,
When I was running HFTA on my QTH in the Santa Cruz mountains, Dean
advised me to to out to 10-15 miles. This ignores small variations,
like the gullies being described. The radial data is a plain text
file, and it is possible to generate your own data from topo maps.
When I started using HFTA, I did a few radials this way as an exercise.
73, Jim K9YC
On Sat,7/16/2016 3:03 PM, StellarCAT wrote:
I use the 10M range data with HFTA exclusively! The 30 is far too
long of a sample point. I'd prefer even smaller if available. I set
up microdem at 5° increments and never have a problem getting the
full data set. Works great.
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