I second Jim's thoughts. I have used N6BV's HFTA at two locations. The
first was at a VERY hilly/mountainous KH6 location and the second was a
relatively flat (compared to KH6) location here in FL. I too, swear by this
program.
If I ever get set up in the Caribbean on a nice hill, you can bet I'll
use the program again.
K4XS/KH7XS
In a message dated 1/4/2015 12:20:26 A.M. Coordinated Universal Time,
k9yc@audiosystemsgroup.com writes:
On Sat,1/3/2015 12:03 PM, Steve London wrote:
> If you are playing with HFTA, I strongly urge you to do a sensitivity
> analysis by changing your datapoints, randomly, by 1 to 3 feet. Do
> this on each band of interest. If the results change significantly,
> then HFTA is not a valid model at your QTH.
I believe that's an incorrect conclusion, Steve. N6BV, HFTA's author,
recommends making multiple runs to rule out the granularity issue that
you noted. That is, he suggests modeling not at single heights or
azimuths, but at multiples of both. He advises that it IS possible to
have a condition that yields bogus results, but by doing those multiple
calcs, it's easy to weed them out.
For my QTH, which is far more irregular than yours, I modeled in 5
degree steps from 0 to 45 degrees, at 5 ft height increments. Knowing my
terrain, he also recommended going out something like 10 miles or more.
Many of us out here in the Bay area have used HFTA extensively, and
swear by it. I know that K6XX has, and so have I. My on-the-air
experience with a SteppIR at 120 ft and monobanders in the range of
30-45 ft is in great agreement with the models.
73, Jim K9YC
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|