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RE: UO-14 polarisation - Arrow antennas



> 
> I understand the need to reduce coupling
> between the two, but I'm curoius as to
> the influence polarisation difference 
> has on performance,when making a 
> QSO via UO-14.

In reality, it doesn't make much difference.  The reason is that effects
such as Faraday rotation (which affects different frequencies differently)
means that the polarisation of the signals at ground level is not always the
same as when it left the bird (and vice-versa).

> Do operators using this antenna simply
> transmit with a 90 degree polarisation
> difference (to their Rx signal), or do 
> they "twist" the antenna when transmitting
> to correct this?

In practice, I reveive with optimum downlink reception.  During transmit, I
adjust for best overall performance (yes, that means simultaneously
listening and rotating the antenna, while conducting the QSO! :) ).
 
> If the first case is true, is this an advantage?
> (Is it worth remounting my own antennas
> so that they too, have a 90 degree difference?
> Actually, it's obviously worth trying it anyway!!!)

The greater advantage is in the lower coupling, especially in Mode J.

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