[TowerTalk] tool to retrieve data and build HFTA profiles

[David Gilbert]

HFTA will, as far as I know, work with almost any distance you choose.  
There seems to be a tacit belief that terrain points out beyond 5,000 or 
6,000 meters are not worth bothering with, but I believe that to be an 
erroneous assumption.  It all depends upon the particular terrain 
involved.  I live on the hillside of a mountain range with a long 
eastward slope that starts out at about 16% for several hundred yards 
and is still sloping downward at 3% to 4% seven miles away.  When I 
compiled my .pro file for Europe I made two versions ... one that 
stopped at about ten miles and one that continued on for fifteen miles 
to catch the next mountain range in that direction.  I can easily see 
the difference when comparing the HFTA plots for the two files.

Now then, is all of that valid?  Maybe not entirely, , but at least it 
shows that HFTA doesn't stop at 6,000 meters and also that for very low 
takeoff angles even far distant terrain features can still have an 
effect.  According to HFTA the peak of my main lobe to Europe and Africa 
is at 4 degrees elevation on 40m , and on 20m it is at 2 degrees, so not 
everybody is likely to have the same situation that I do ... but if in 
doubt add a few more data points further out and see for yourself.

73,
Dave   AB7E



On 3/5/2012 1:32 PM, Dick Green WC1M wrote:
> This sounds terrific, Jim, and will be a huge boon to the amateur radio
> community.
>
> One question: are you proposing to generate .pro files with data out to the
> full 50-60 miles, or just what HFTA can deal with (5000 meters, I think)?
>
> 73, Dick WC1M
>