TopBand: Re: EWE Info

Mon, 27 Oct 1997 10:45:59 +0000

Hi Carl,

> My point here is that there appears to be a lot of discrepancy between
> antenna programs. Floyd uses K6STI's AO and this particular run compares
> well against NEC-Wires. 
> Does anyone here have both AO and EZENEC and would be willing to compare?

These programs are wonderful for antennas or radials some distance 
above earth, but don't expect accuracy with any model when the 
antenna is near something as non-homogeneous as earth.

For examples of errors, look at the elevated radial flap and the 
incorrect model results of the N4KG feed system. There are even 
documented cases of disagreement between full blown NEC-2 and low 
dipoles, when the antennas are very near earth. 

I've made dozens of measurements of Beverages and other low  antennas 
and find only rough agreement with the programs when the height is 
below .05 WL. Earth losses seem to be less important in the models 
than in real life.

> Perhaps the resolve will require old fashion leg work with some test
> equipment.   

That is generally the way things are really proven.

73, Tom W8JI

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