[TowerTalk] Tower height -V- landscape undulations

[Jim Brown]

On Tue, 14 Apr 2009 19:43:38 +0100, John E. Cleeve wrote:

>I discovered the disc inside the back cover.

It is worth chasing down later editions of this program. The 
changes are subtle, but nice. Don't ask me what they were. :) One 
issue you will face is finding terrain data. The program includes 
accessories to download US terrain data and import it into the 
software, but I don't know if that covers your area. (I'm noticing 
your G3 call). 

N6BV, who wrote HFTA, is a member of our local contest club. When 
I was getting started, I had trouble getting the terrain data 
import to work, and he pointed me to an update of the procedures 
on the ARRL website. That was three years ago, and the current 
version probably has those updates. 

You CAN, however, manually input data from your own terrain maps. 
You do this by drawing radials for several miles from your QTH on 
a topological map and picking off points at suitbable intervals, 
then manually entering that data. When I was in the process of 
learning HFTA, I did that for two radials at my own QTH. A lot of 
work, but it works. As I recall, it took me an hour for the first 
radial, about half that for the second. My terrain is QUITE 
irregular, and N6BV's advice was to use the most detailed data I 
could get (the more detailed of the online data).  

73,

Jim Brown K9YC