[TowerTalk] HFTA Accuracy / Usefulness

[Steve Hunt]

Pete,

How interesting - I was certainly unaware of your prior work.

As you can see from my web site I came at this in the context of Hexbeam 
- I was continually being asked "what's the best height". So I felt I'd 
better try and spell out some of the issues. I decided early on that a 
logarithmic figure of merit was the right approach because most of us 
think in those terms, and it seemed clear that any "averaging" would be 
invalid unless I converted to linear units.

I was vaguely aware of the debate over the antennas used to generate the 
ARRL stats. Pragmatically, all I would say is that if there are no other 
stats freely available at this stage the argument is interesting but 
academic :)

I was pleased, but surprised, that QST accepted the article for 
publication. Surprised because they seem to steer clear of anything as 
frightening as a mathematical formula :)

Steve G3TXQ

Pete Smith wrote:
>
> Steve, I published substantially the same method in the US National Contest 
> Journal in January 2001, with a correction in the September/October issue 
> to incorporate the point about applying the weighting to linear rather than 
> logarithmic relationships.  N6BV incorporated a Figure of Merit using the 
> same method in the first version of HFTA, which has been out since around 
> 2003 or 2004.
>
> A rather more interesting question to me, at this point, is what antennas 
> should be specified for the two ends of the path to generate the arrival 
> angle statistics.  There is a discussion of this on the ARRL TIS web page, 
> but as far as I'm concerned the jury is still out on that subject; in the 
> past, I had argued for isotropic antennas on each end of the path, so that 
> the statistics would reflect the actual behavior of the ionosphere rather 
> than the selection of antennas.  I'm now coming around to a somewhat 
> different view, if what you're interested in is trying to open up the most 
> "layers" of stations to work in a contest, for example.  At some point, the 
> lowest layers are guys with low dipoles or lossy ground-planes.
>
> With luck maybe we can smoke Dean out and restart the discussion.
>
> 73, Pete N4ZR
>
>    
>
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