Topband: Modeling verticals (fat, skinny, etc) on EZNEC

[David Gilbert]

Telegrapher9 at aol.com wrote:
> Right you are Sinisa.
>
> I think we are having a semantic issue here. I know that you understand what 
> I'm saying and I'm saying it just to try to clarify the issue. 
>
> Did Tom, W8JI, mean 100% horizontal polarization followed 90 degrees later by 
> pure vertical polarization - what we would have with circular polarization? 
>
> You are referring to an antenna - a dipole - having linear polarization. It 
> is tilted 45 degrees from the vertical. A good proof of your assertion is that 
> a verically polarized antenna will receive the signal from your tilted dipole. 
> And a horizontally polarized antenna will receive the signal from your 
> titlted dipole. If your antenna did not radiated both vertically polarized and 
> horizontally polarized energy this would not happen. The receive antennas mentioned 
> cannot, using only one, distinquish between the combined vertical/horizonal 
> polarization of the tilted dipole and true circular polarization. 
>
>     Dave WX7G

Sorry, Dave, but unless I misunderstand your point that simply is not 
true.  A tilted dipole has only one polarization (except for end 
effects) and that polarization is similarly tilted.  Any receiving 
antenna that is not orthogonal will receive some portion of the 
transmitted energy per a cosine function of the relative angle between 
it and the transmitting antenna.  It does not require that the 
transmitting antenna radiate in both polarizations for this to happen.

Maybe we need to get away from the semantics of vertical and 
horizontal.  Picture a transmitting dipole in free space where there is 
no absolute physical orientation.  I think we could agree it radiates 
energy of a single polarization.  Now put a receiving antenna some 
distance away oriented at whatever angle you wish.  The magnitude of the 
received energy will follow a cosine function as you rotate the 
orientation of the receiving antenna with respect to the transmitting 
antenna.  It's a simple matter of vectors.  No multiple polarizations ...

Dave   AB7E

-- 

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