But he should worry if he plans to reuse existing antennas. If the antenna coupling is rectangular, theses no way to inject both polarities into it.
On Fri, Oct 30, 2015 at 1:04 PM, Daniel White <afmu...@gmail.com> wrote: > I agree... we are saying the same things... just in different ways :-) > > Many vendors now are utilizing integrated OMT's... the Ceragon IP-20S uses > it for instance. > > Long story short - don't worry if the BOM says Single Pol if it includes an > OMT. > > Thank you, > > Daniel White > afmu...@gmail.com > Cell: +1 (303) 746-3590 > Skype: danieldwhite > Social: LinkedIn: Twitter > > > > -----Original Message----- > > From: Af [mailto:af-boun...@afmug.com] On Behalf Of ch...@wbmfg.com > > Sent: Friday, October 30, 2015 10:41 AM > > To: af@afmug.com > > Subject: Re: [AFMUG] Dish polarity question > > > > I think Daniel and I are saying the same things. > > > > -----Original Message----- > > From: Daniel White > > Sent: Friday, October 30, 2015 10:13 AM > > To: af@afmug.com > > Subject: Re: [AFMUG] Dish polarity question > > > > This comes up all the time with many manufacturers. > > > > Almost all licensed microwave antennas a WISP is going to come in contact > > with have circular feedhorns, meaning their polarity is determined by the > > interface on the feedhorn. Typically, they are rectangular and single > polarity. > > > > Then an OMT is added... depending on the radio it may be an external or > > internal device. This combines the transmitters into a circular feed. > > > > No voodoo required. The OMT makes a single polarity dish dual polarity. > > > > Thank you, > > > > Daniel White > > afmu...@gmail.com > > Cell: +1 (303) 746-3590 > > Skype: danieldwhite > > Social: LinkedIn: Twitter > > > > > -----Original Message----- > > > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Craig Baird > > > Sent: Friday, October 30, 2015 10:07 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 > > > > > > > > --- > > This email has been checked for viruses by Avast antivirus software. > > https://www.avast.com/antivirus > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > >
