Uh Oh... I have opposite opinions from two guys (Chuck and Daniel)
whose opinions both carry a lot of weight. Now I'm back in the
undecided camp... Anyone else care to chime in? Can an OMT turn a
single-pol dish into a dual-pol?
Craig
Quoting ch...@wbmfg.com:
A circular waveguide will conduct all polarizations at the same time.
If the radio and antenna both have circular waveguide interfaces,
the radio can put both polarizations out at the same time.
You cannot use a single pol antenna.
-----Original Message----- From: Craig Baird
Sent: Friday, October 30, 2015 10:06 AM
To: af@afmug.com
Subject: [AFMUG] Dish polarity question
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
