EZNEC does display the pattern in free space, but it also gives the
pattern over ground (of any characteristics) at any height, but only for
flat ground. EZNEC cannot handle arbitrary terrains. For this you need
HFTA. However HFTA cannot handle arbitrary antenna designs. HFTA works
with single half wave elements or multiples thereof (2, 3, 4, etc...
element yagis, or stacks).
So you need both.
Bill Tippett wrote:
> >I'll be happy with a model of the 3 element SteppIR tuned to 28MHz.
>This isn't the first time I've used EZNEC, but typically I start with
>something similar to what I want then just modify as necessary. I
>didn't find a 3 element yagi example in my batch of models from the
>ARRL Antenna Book. I may have missed it if it is there.
> There is a standard model of a 3 elementNBS Yagi for 50 MHz
>included with EZNEC. You
>could re-scale it for 28 MHz, but...
> EZNEC displays the pattern in free space,
>which is not very useful. You really need to
>look at vertical patterns over ground to see
>the effect of ground reflection vs antenna
>height using a program like YT (included with
>the 18th and 19th editions of ARRL's Antenna
>Book) or its successor HFTA in the 20th edition.
>The vertical pattern over real ground differs
>dramatically depending on height above ground.
> 73, Bill W4ZV
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