[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
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
Re: [AFMUG] Dish polarity question
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
Re: [AFMUG] Dish polarity question
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
Re: [AFMUG] Dish polarity question
OMT is an ortho mode transducer. It takes two polarities and puts them both on a circular waveguide. From the OMT forward, the feedhorn must be circular. The OMT can be built into a radio or it can be external and have two radios attached. (Like Exalt) I am speaking in generalities, not to your specific radio. A true single pol dish will only transmit one polarization. Most feedhorns are circular with a dielectric lens and cassegrain reflector built into the lens. But at the back of the dish, sometimes you have a rectangular waveguide transition to adapt a rectangular waveguide radio to the circular feed tube. But many radios have a circular waveguide interface, even if they are single pol. DW for instance. -Original Message- From: Craig Baird Sent: Friday, October 30, 2015 10:33 AM To: af@afmug.com Subject: Re: [AFMUG] Dish polarity question 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
Re: [AFMUG] Dish polarity question
I meant that Exalt has the OMT built in on some of their dual pol radios. -Original Message- From: ch...@wbmfg.com Sent: Friday, October 30, 2015 10:39 AM To: af@afmug.com Subject: Re: [AFMUG] Dish polarity question OMT is an ortho mode transducer. It takes two polarities and puts them both on a circular waveguide. From the OMT forward, the feedhorn must be circular. The OMT can be built into a radio or it can be external and have two radios attached. (Like Exalt) I am speaking in generalities, not to your specific radio. A true single pol dish will only transmit one polarization. Most feedhorns are circular with a dielectric lens and cassegrain reflector built into the lens. But at the back of the dish, sometimes you have a rectangular waveguide transition to adapt a rectangular waveguide radio to the circular feed tube. But many radios have a circular waveguide interface, even if they are single pol. DW for instance. -Original Message- From: Craig Baird Sent: Friday, October 30, 2015 10:33 AM To: af@afmug.com Subject: Re: [AFMUG] Dish polarity question 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
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
Re: [AFMUG] Dish polarity question
A parabolic dish doesn't really have a polarity (at least none of the ones I've seen). The polarity comes with the feedhorn and waveguide. A rectangular waveguide will be polarized, but a circular waveguide will essentially accept all polarities. If you're using an OMT (sometimes called an OMC), it will utilize a circular waveguide to feed two opposite (or more correctly orthogonal) waves into the dish. The OMT is not making anything circularly polarized. It's just using the circular waveguide (which accepts all polarities) to feed two separate waves. bp On 10/30/2015 9:06 AM, Craig Baird wrote: 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
Re: [AFMUG] Dish polarity question
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
Re: [AFMUG] Dish polarity question
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 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 > >
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 : 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
Re: [AFMUG] Dish polarity question
Interesting... this is exactly what I'm wondering... see my last post... Craig Quoting Gino Villarini : 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 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
Re: [AFMUG] Dish polarity question
If the antenna vendor and OMT vendor are the same, may not be an issue. Worst case if there is a waveguide flange, you can buy a waveguide OMT and do waveguide + remote mounts for the radios. 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 11:24 AM > To: af@afmug.com > Subject: Re: [AFMUG] Dish polarity question > > Interesting... this is exactly what I'm wondering... see my last post... > > Craig > > > Quoting Gino Villarini : > > > 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 > 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 > >> > >> > > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: [AFMUG] Dish polarity question
If it is a circular waveguide flange. If the antenna has a rectangular waveguide flange the OMT will not work with it. -Original Message- From: Daniel White Sent: Friday, October 30, 2015 11:29 AM To: af@afmug.com Subject: Re: [AFMUG] Dish polarity question If the antenna vendor and OMT vendor are the same, may not be an issue. Worst case if there is a waveguide flange, you can buy a waveguide OMT and do waveguide + remote mounts for the radios. 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 11:24 AM To: af@afmug.com Subject: Re: [AFMUG] Dish polarity question Interesting... this is exactly what I'm wondering... see my last post... Craig Quoting Gino Villarini : > 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 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 >> >> > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: [AFMUG] Dish polarity question
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 : 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
Re: [AFMUG] Dish polarity question
VHLP and RW antennas that are sold with the 820S work with an OMT -Original Message- From: Af [mailto:af-boun...@afmug.com] On Behalf Of ch...@wbmfg.com Sent: Friday, October 30, 2015 12:41 PM 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
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 : 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
Re: [AFMUG] Dish polarity question
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 : > > > >> 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 >
