[TowerTalk] HTFA and Reality

[Kjeld Holm]

Dear Pete (and others)

Thanks for your quick and informative answers.

I think I must go for a single Force 12 C3SS as high as possible. I cannot
go for a bigger antenna as the perimeter of the rotating antenna (turning
radius) will go too near my neighbours at a hight 26 feet. Going from C3SS
to a longer boom (C31XR) will raise turning radius from 13.6, to 23.8 feet
lowering allowable height to 13 feet. Modelling the bigger antenna at 13
feet shows inferior performance.

Vy 73
OZ1CCM Kjeld


-----Original Message-----
From: Pete Smith [mailto:n4zr at contesting.com] 
Sent: 23. januar 2007 13:21
To: Kjeld Holm
Subject: Re: [TowerTalk] HTFA and Reality

Kjeld - you are right to be skeptical - HFTA uses a point-source modeling
technique for each individual antenna, which causes unrealistic results at
very close spacings.  Intuitively, given your QTH, I believe that a
longer-boom tribander at the highest available point will perform best.

73, Pete N4ZR

At 05:02 AM 1/23/2007, you wrote:
>Gentlemen:
>
>I am using HFTA in planning for an array for 10 to 20 m. Due to zone 
>restrictions I am modelling a lot of solutions - normal and crazy ones 
>among each other. As I may end up being restricted to a top point of 26 
>feet I modelled a 4 stack of 2 elements yagis at 17/20/23/26 feet. 
>According to HTFA this should work fine on all three bands (less 
>performance on 20 m of course). But I do not believe in such a close 
>spacing in the real world. Any comments would be appreciated.
>
>Vy 73
>OZ1CCM Kjeld
>
>PS I am located on a 190 feet hill top with rather steep sides.
>
>Some months ago I had a question about a low yagi for 40 m and I would 
>like to thank every body who told me that the only way to find out 
>anything was to use HFTA.
>
>
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