[TowerTalk] Polarization Change

Roger (K8RI) K8RI-on-TowerTalk at tm.net
Thu Apr 9 22:01:34 PDT 2009


K7LXC at aol.com wrote:
OK, I'll try completely eliminating any mention of the "Other thread's 
name"<:-))
>  
> In a message dated 4/9/2009 11:24:16 A.M. Pacific Daylight Time,  tower
> talk-request at contesting.com writes:
>
>  
>>  I remember reading a study back some years ago about the  benefits 
>> or     
> lack
> there of, in using a vertically polarized antenna as  oposed to a
> horizontally polarized antenna for long distance work. It read  that 
> there is
> little significant difference between the two at the recv end  as the F2
> layer influences ( for lack of a better word and my memory)
My take which may be completely out in left field but it does have some 
backing in physics:
Refraction (roughly speaking), means the wave front is bent and may be 
broken into many segments that are sent in many directions rather than 
what we'd expect from a reflection which is often erroneously referred 
to in prorogation.  With many refractions the wave front is fractured in 
polarization while arrival times differ due to the different distances 
traveled. So we not only receive multiple portions of the wave front 
that have many components of polarization, but time as well. Each 
component adds to all the others (of it's own type) algebraically.   So, 
theoretically we should end up with selective fading  due not only to 
phasing (time), but polarization as well.

An analogy to  the polarization would be the direct reflection in a 
mirror would result in 180 degrees, but in refraction the wave appears 
to be bent randomly with a bit of rotation added, or subtracted for 
each  bit of the refraction.  The amount of refraction is complex as it 
depends on how highly ionized as well as how dense and the general 
altitude of the ionization layer.  F2, F3... Think of how a light beam 
scatters in dust or fog.

I hope all that made at least a little sense.
>   change these
> signals into primarily horizontally polarized signals  anyway.  Does 
> it make
> sense? Anyone have thoughts on  that?  
>     You bet. The winning strategy is to have a CHOICE  of antennas per 
> band. At any time, one will always outplay the other(s).
>   
Some times in rapid order.

73

Roger (K8RI)
>  
> Cheers,
> Steve      K7LXC
>



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