Spurred on by you two I have just revisited MMANA-GAL with the 
simulation of my 500kHz vertical - pretty similar to your top loaded 
designs but without any top loading. I have shown it resonates 
(approximately at the correct frequency) and my model (attached) 
shows how to add a loading coil (in my case at 1m height) and base 
fed with the source.

I have now found out that all NEC models do not use the ground 
characteristics in calculating impedance, they only use them for the 
radiation plots. Hence you will see that mine has a resistive 
impedance of 0.136 ohms which is just the radiation resistance. When 
you have 50-100 plus of earth losses this will of course add to the 
impedance and makes the use of the program for impedance matching and 
efficiency calculations effectively useless.

73 Dave G3YMC

On 28 Dec 2007 at 18:45, Graham wrote:

> Ok Thanks for that Rik,
> 
> Thats the basic layout , ive only 2 top wires , but thats the layout
> .. I see you have a load defined in the geometry listing , but where
> on the ae is it located ? , I found one post on the user group , where
> a  element could be given a short  lenght and have inductance added to
>  it .. that way you could control where the coil  was placed
> 
> My ae has the 'coil' at the 90 deg bend , top of the vertical section
> , if i could work out how to  add that, I  would be half way there !
> the earth system would be the other half  hihi
> 
> Tnx
> 
> Graham ..

http://www.davesergeant.com

g3ymc500kvert.maa
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