[AFMUG] Dish polarity question

[Craig Baird]

We are getting ready to put up a licensed 11 GHz 2+0 link using  
Cambium PTP820S radios.  We have two 11 GHz frequencies that are  
oppositely polarized for use on this path.  I had assumed that we  
would need to use dual polarity dishes in order to make this work, but  
Cambium and our vendor are saying that we need to use single-pol  
dishes.  This completely baffles me.  How can a single-pol antenna  
transmit in two polarities?  Cambium's answer is that it's because  
we're using an OMT, and that device essentially makes the single-pol  
antenna circularly polarized, so it will transmit both polarities.  My  
first thought is "what kind of voodoo is this?"  Will this really  
work???  I'd sure hate to start transmitting, only to find out from an  
existing license holder that we're interfering with them because one  
of our frequencies is coming out the antenna in the wrong polarity.   
Can someone confirm for me that this will really fly?

Thanks!
Craig