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Re: [TowerTalk] EZNEC- needs improvement

To: towertalk@contesting.com
Subject: Re: [TowerTalk] EZNEC- needs improvement
From: Steve Hunt <steve@karinya.net>
Date: Sun, 05 Apr 2009 21:56:23 +0100
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Jerry,

Are we sure we're looking at the EZNEC results carefully enough.

If I compare a 160m half-wave at 300ft with a ground-mounted 
quarter-wave vertical, over average ground, the vertical has the 
advantage at take-off angles under 10 degrees by as much as 8dB.

That of course is in the dipoles favoured direction. At low angles the 
dipole is exhibiting a front to side as high as 18dB, so the vertical 
would have a considerable advantage at low angles for much of the 
azimuth. In the dipole's worst direction the vertical beats it for all 
angles below 66 degrees.

And anything better than Average Ground favours the vertical even more.

Steve G3TXQ

K4SAV wrote:
> The only time I have verified EZNEC being different from my real world 
> measurements is usually because of some error I put into the model or 
> something I left out of the model.  However I can't do comparisons of 
> high dipoles and verticals on 160 at my station because I don't have 
> them.  I can look at data generated by others (who are likely to not be 
> in error) and check that with EZNEC.  In the case of 160 (and only 160) 
> I can't get their results to agree with EZNEC.  So I'm wondering if 
> there is some magic on 160 that says a vertical get a special advantage, 
> and what the heck is it?
>
> EZNEC says a 300 ft high dipole on 160 beats a quarter wave vertical at 
> all elevation angles under 54 degrees even if I assume zero near field 
> ground loss for the vertical.  Real world data disagrees.
>
> By the way, this disagreement doesn't exist on 80 meters.
>
> Jerry, K4SAV
>
>   
>   

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