[Antennaware] Height

[Guy Olinger, K2AV]

In an urban setting, with so much clutter on the ground, a useful assumption for conservative estimating is that the energy radiating from the antenna at an angle below the horizon will be mostly lost. 

Further, since there are many ways to reradiate energy from the clutter, the energy lost from what would have been the main pattern will fill in expected deep nulls to very odd directions, giving the appearance that the antenna is missing some degree of front-to-back or front-to-side, in a rather random fashion.

Separating this from the antenna's actual performance would be close to impossible. 

As previously posted, the main lobe above the horizon would be OK using the 25m elevation, and defining your ground as "very, very poor".

73, Guy.

> 
> From: Fabio <fabio.mantovani at inwind.it>
> Date: 2003/04/17 Thu PM 12:45:28 EDT
> To: "owe persson" <sm3cwe.owe at telia.com>,  antennaware at contesting.com
> Subject: Re: [Antennaware] Height
> 
> At 16.16 17.04.2003 +0200, you wrote:
> >Hi,
> >It depends on how much of steel and things you have in the house,
> >but I should think that you can count on 25 mtrs when you are doing
> >your calculations, e g your antenna will be on  >1 lambda on 14 MHz
> >and you will have a main-takeoff of approx 12 degrees and one takeoff
> >at 38 degrees approx about 4 dB down from mainloob.
> >Good luck with the construction!
> >73 de Owe /SM3CWE
> 
> Thanks Owe!
> Moreover, I am in a city, so I think that modeling urban conditions becomes 
> too complex, for me and for NEC probably
> I will model @25m and I'll take the conclusions with a little of 
> pessimism... that could be a good compromise HI
> Thanks again,
> Ciao
> Fabio IZ4AFW
> 
> 
> --
> EMail                   fabio.mantovani at inwind.it
>                          iz4afw at amsat.org
> Home Page               http://www.qsl.net/iz4afw
> 
> 
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73, Guy
K2AV