[TowerTalk] HFTA question

[cqtestk4xs at aol.com]

In a message dated 1/21/2010 3:50:05 PM Greenwich Standard Time,  
jim at audiosystemsgroup.com writes:

HFTA can  handle any distance that you choose to enter. The limitation is 
the 
number  of data points for each radial. So there would be no problem 
including  
that mountain in your analysis. 


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
One additional piece of info.  The further away the terrain  the less of an 
effect it will have.  N6BV was kind enough to run some  numbers for me and 
the numbers for the terrain were computed up to around  14000 ft.  He told 
me there was no reason to go to any further than  that.
 
If the land surrounding your location is just slightly hilly  without big 
dips and so forth you can probably get by with a number for every  100 feet 
running out to maybe 5000 ft.  That would make it easier to input  the 
numbers if you are using Google Earth.  If you saw a big difference  from the 
"flat terrain" I would continue to run the numbers out  further.
 
I'm a firm believer in the program, but one caveat......The program  starts 
to break down when you start putting like antennas too close to each  other 
in stacks.  The gain figures become inflated.  As long as you  keep the 
antennas at least 1/2 wavelength apart, the numbers should be  good.
 
Bill KH7XS