Remec has circular and rectangular interfaces. Rectangular I believe is the more common one.
What you describe though happens more often than you would think. Don't kick yourself too hard. Another common mistake is people not knowing what a vertical or horizontal waveguide looks like... I think it looks counter-intuitive as well even though I understand how waveguide works :-) 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 George Skorup > Sent: Friday, October 30, 2015 11:31 PM > To: af@afmug.com > Subject: Re: [AFMUG] Dish polarity question > > So I made a stupid a couple weeks ago not paying attention. We installed > some Exalt ExtendAir G2 radios on their custom Radiowaves HP2 and HP3 > dishes. You have to take two screws out and rotate the waveguide interface > on the dish itself from the default vertical if you need horizontal. I ended up > installing the radio horizontal onto the antenna with the waveguide still > vertical. There's two index pins and I have no idea how I didn't catch it and > the radio latched without a problem, so I had to send one of the guys back up > to take the radio off, rotate it and then reinstall. But anyway, it is circular > under that rotatable piece, obviously not anything standard like a Remec > interface though. > > On 10/30/2015 12:55 PM, ch...@wbmfg.com wrote: > > That rectangular hole has some steps inside to convert the impedance > > to that of the circular feed tube. > > It will only accept one polarity. > > > > I might could convert it to circular for you if you picked the OMT > > first. > > > > -----Original Message----- From: Craig Baird > > Sent: Friday, October 30, 2015 11:22 AM > > To: af@afmug.com > > Subject: Re: [AFMUG] Dish polarity question > > > > Okay. So, let me throw another wrinkle in the mix. I'm wanting to > > use an 8-foot Radiowaves dish that we've had in storage for this shot. > > Looking at the back of the feedhorn, there is a plate where the > > flexible waveguide attaches. That plate has a rectangular hole in it. > > However, I can see that underneath that rectangular hole the > > waveguide is actually circular. So, could I use an OMT with such a > > configuration? Would have have to replace that plate with one that > > has a circular hole instead of a rectangular one? > > > > Craig > > > > > > Quoting Daniel White <afmu...@gmail.com>: > > > >> 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 > >> > >> > > > > > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
