[TowerTalk] Vertical Pattern of a yagi
larry at k7mi.com
Mon Apr 24 18:46:39 EDT 2006
This is not true. EZNEC will model antennas in free space and over real
ground and you can even select the type of ground.
----- Original Message -----
From: "Bill Tippett" <btippett at alum.mit.edu>
To: <towertalk at contesting.com>
Sent: Monday, April 24, 2006 3:18 PM
Subject: Re: [TowerTalk] Vertical Pattern of a yagi
> >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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> TowerTalk at contesting.com
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