It would need to be studied in-depth as there are numerous channel plans (10, 30, 40 & 80 MHz) all with different overlaps. The interference potential between these two would be completely different. For the example previously listed with a transmitted frequency pair 10855.0 / 11345.0, the adjacent and semi-adjacent channel roll-offs are in completely different places. From a very basic sense, this would be a waste of spectrum (112 MHz radio falsely usurping 120 MHz of spectrum) and I know that a similar thing was done with 56 MHz bandwidth radios in an 80 MHz slot at 11 GHz or a 60 MHz one in lower 6 GHz. However, this spectrum is not wasted as the actual occupied bandwidth is used in the analysis, not the channel bandwidth.
> On Jan 6, 2021, at 10:17 AM, Mike Hammett <af...@ics-il.net> wrote: > > Not from a legal perspective, but from a technical perspective. > > If an 80+40 = 112 setup was no worse at the channel edges, why would it > matter what happened in the middle? > > > More asking than arguing. > > > > ----- > Mike Hammett > Intelligent Computing Solutions <http://www.ics-il.com/> > <https://www.facebook.com/ICSIL> > <https://plus.google.com/+IntelligentComputingSolutionsDeKalb> > <https://www.linkedin.com/company/intelligent-computing-solutions> > <https://twitter.com/ICSIL> > Midwest Internet Exchange <http://www.midwest-ix.com/> > <https://www.facebook.com/mdwestix> > <https://www.linkedin.com/company/midwest-internet-exchange> > <https://twitter.com/mdwestix> > The Brothers WISP <http://www.thebrotherswisp.com/> > <https://www.facebook.com/thebrotherswisp> > > > <https://www.youtube.com/channel/UCXSdfxQv7SpoRQYNyLwntZg> > From: "Tim Hardy" <thardy...@gmail.com> > To: "AnimalFarm Microwave Users Group" <af@af.afmug.com> > Sent: Wednesday, January 6, 2021 8:49:17 AM > Subject: Re: [AFMUG] 2+0 Co-Polar > > Part 101 was derived from the old Part 21 that was developed in the late 60s > / early 70s to facilitate equal sharing of the bands between the incumbents > (AT&T, Bell System, WU, GTE, United, Continental) and the newly approved > Specialized Common Carriers (MCI et al). Prior to 21.100(d) - the Prior > Coordination rule and requirement (now 101.103d) - the FCC acted as sole > arbiter of all interference related issues. New proposals would be filed, > placed on Public Notice and all incumbents had 30-days to file formal > petitions or let them go. The FCC was inundated with these filings, and > processing ground to a complete halt. The FCC did not have a database, the > license data was kept on paper in large filing cabinets, and they certainly > didn’t have programs (let alone computers) to calculate all of these cases. > It was recognized early in this process that the FCC should get out of the > process and leave this pre-filing analysis and assignment to industry so they > convened a meeting with incumbents (affectionally known as “The Gang of > Twelve” by those of us that were there) to develop rules and requirements to > promote efficiency and enable access to the spectrum to all qualified > applicants. > > Spectrum efficiency in fixed bands is dependent on standardized frequency > plans, standard transmit - receive separations, required antenna performance, > required loading or bit efficiency, maximum power levels, etc. etc. and all > of the rules were developed with these thoughts in-mind. Bear in-mind that > everything was analog at the time and there are still vestiges of these > differing requirements in the rules. There have been at least two or three > major NPRMs with updates and changes over the years, but the basic framework > really hasn't changed much as it was based on sound EMI-EMC principles. > > Sorry for the long-winded history lesson, but I hope it helps give some > background behind Part 101. The specific issue discussed here, coordinating > and licensing an 80 MHz channel pair along with a 40 MHz pair in an effort to > block out 120 MHz chunk, and then use one radio at 112 MHz bandwidth within > that 120 MHz, does indeed violate at least two and possibly three major rule > parts. The rules involved here would be 101.103, 101.109 & 101.147, plus the > scheme would result in an actual transmit frequency that has not been > coordinated and more importantly, is not on the station license. As an > example, the path is coordinated with 80 MHz channel pair 10835.0 / 11325.0 > MHz & 40 MHz channel pair 10895.0 / 11385.0 MHz to cover 120 MHz of > contiguous spectrum. The actual transmit frequency using 112 MHz bandwidth > cannot be any of the above channel pairs since the emission would extend > beyond the edge of that 120 MHz chunk. In this example, the user would have > to operate on 10855.0 / 11345.0 MHz, a channel pair that has not been > coordinated and is not on the license, and subject to substantial fine and > forfeiture if caught. > > If someone is hell-bent on doing this, the only legal way is to coordinate > the actual transmit frequency along with the actual emission bandwidth and > designator (112M0D7W). The applications would all require at least two rule > waivers (there are fees for waivers and these are the kind that would require > assistance from a law firm that regularly works on Communications law - $$) > along with a substantial technical showing why these waivers are required > (financial reasons are usually dismissed). Rule waivers automatically > eliminate conditional authorization and the applicant must wait for formal > FCC license grant before beginning operation. These kinds of substantial rule > waivers can take years to make their way through the system and at the end of > the day, most are denied. > > The better way to attack this, if there really is a pressing need, is to get > enough licensees, trade associations, etc. interested in it and file a > request for rule making. This process also takes years unless it has a ton of > support along with political influence. Good Luck! > > On Jan 5, 2021, at 1:23 PM, Ken Hohhof <af...@kwisp.com > <mailto:af...@kwisp.com>> wrote: > > I’ll let Tim respond, but here’s my take. It’s not a rule saying you can’t > do it, but rather a license to do something else. Frequency coordinators and > other users of the band rely on you following the license you obtained. To > do something else, based on a totally different ETSI standard that isn’t even > valid in this country, is not what you’re licensed for. > > Reducing the equipment certification and frequency coordination process down > to just the channel width from the brochure oversimplifies things. Your > license specifies a certain modulation, and the radio will have certain out > of band emissions, when used according to the license. The coordinated EIRP > also assumes the 2 separate channels, not one wide channel. > > Before you got the license, you weren’t allowed to use the band at all. Once > you get the license, you are authorized to use the band as specified in the > license. Not something you feel is equivalent. > > > From: AF <af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com>> On Behalf > Of Ryan Ray > Sent: Tuesday, January 5, 2021 12:09 PM > To: AnimalFarm Microwave Users Group <af@af.afmug.com > <mailto:af@af.afmug.com>> > Subject: Re: [AFMUG] 2+0 Co-Polar > > Hey Tim, > > Does this rule have a reason? Or is it just a rule for rule's sake? > > > On Tue, Jan 5, 2021 at 4:47 AM Tim Hardy <thardy...@gmail.com > <mailto:thardy...@gmail.com>> wrote: > A note of caution: Some vendors have been pushing the notion that at 11 GHz, > one can coordinate and license an 80 MHz bandwidth pair along with a 40 MHz > bandwidth pair separated by 60 MHz to in effect get a contiguous 120 MHz of > spectrum. This is okay as long as you are transmitting two distinct frequency > pairs - one with 80 MHz, and the other with 40 MHz. In the US it is NOT okay > to unlock the radio to use ETSI 112 MHz bandwidth and transmit a single pair. > Vendors that are pushing this concept need to stop as it violates at least > two and possibly more FCC Rules. The licensee would be taking the risk - not > the vendor. > > > On Jan 4, 2021, at 3:54 PM, <joseph.schr...@siaemic.com > <mailto:joseph.schr...@siaemic.com>> <joseph.schr...@siaemic.com > <mailto:joseph.schr...@siaemic.com>> wrote: > > With the SIAE radio: > - 2+0 XPIC - minimal loss using the built-in OMT branching unit on the > order of 0.5 dB per end > - 2+0 ACCP - 3.5 dB loss per end using the built-in Hybrid branching unit > No TX power back-off required in either mode, nor do you need to back-off the > TX power when using POE. > > The ALFOPlus2XG radio has independent modem & RF, so there is flexibility on > how you could setup each radio. Each carrier can have its own channel > bandwidth & modulation. > > The branching units are field changeable and allow the ODU to bolt directly > to the back of the antenna. > > > Thanks, > > <Mail Attachment.jpeg> > > Joe Schraml > VP Sales Operations & Marketing > SIAE Microelettronica, Inc. > +1 (408) 832-4884 > joseph.schr...@siaemic.com <mailto:joseph.schr...@siaemic.com> > www.siaemic.com <http://www.siaemic.com/> > > >>> Mathew Howard <mhoward...@gmail.com <mailto:mhoward...@gmail.com>> > >>> 1/4/2021 12:01 PM >>> > Yeah, you can do 2 x 80mhz channels with a single core on some radios, but > there are some limitations. Depending on the radio, my understanding is that > they have to either be adjacent, or very near each other (definitely within > the same sub-band). It seems to me that some radios can even do two different > sizes of channels (like 1 80mhz + 1 40mhz), but I could be remembering that > wrong. If I understand it right, the Aviat radios have a significant tx power > hit when you activate that feature, which probably makes it unusable in a lot > of cases. We're doing that on a Bridgewave 11ghz link (using 4x 80mhz on a > dual core radio), and there's it works fine, with only a minor performance > hit on those radios. SIAE does have that feature as well, but I don't > remember if there was a significant performance hit or not... I think they > may have been the ones that could use two different sizes of channels. > > On Mon, Jan 4, 2021 at 1:51 PM Ken Hohhof <af...@kwisp.com > <mailto:af...@kwisp.com>> wrote: > Probably, LinkPlanner is pretty smart. > I assume you don't want to use 2 antennas. > There are some licensed radios now that I think can do 2 x 80 MHz channels in > a single core, like from Aviat or SIAE maybe, I don't know if this gets > around the splitter cost and performance issues. I may have that feature > completely wrong, I haven't looked into it. There could also be a performance > hit by using the same xmt power amp for 160 MHz. > I also haven't checked out the full feature set of the new PTP850C, the only > thing I know it has is SFP+. > > ---- Original Message ---- > From: "Adam Moffett" <dmmoff...@gmail.com <mailto:dmmoff...@gmail.com>> > Sent: 1/4/2021 1:30:45 PM > To: af@af.afmug.com <mailto:af@af.afmug.com> > Subject: Re: [AFMUG] 2+0 Co-Polar > > Ok yeah, the Link Planner BOM shows some splitters. I wonder if Link > Planner already accounted for the additional losses when I selected "Co > Polar" on the dropdown. > > > On 1/4/2021 2:25 PM, Ken Hohhof wrote: > > I seem to remember that different channel different polarization is the > > best, if your radio manufacturer charges for an XPIC license key. Next best > > is XPIC. And that the problem with different channel same polarization is > > you need a splitter which costs several dB of system gain. But that's from > > memory, and mine is not so reliable. > > > > ---- Original Message ---- > > From: "Adam Moffett" <dmmoff...@gmail.com <mailto:dmmoff...@gmail.com>> > > Sent: 1/4/2021 1:16:26 PM > > To: "AnimalFarm Microwave Users Group" <af@af.afmug.com > > <mailto:af@af.afmug.com>> > > Subject: [AFMUG] 2+0 Co-Polar > > > > I'm looking at a path where the coordinator can get me two 50mhz XPIC > > channels, or two 80mhz H-Pol channels. > > > > I've never installed co-polar. Do you need a lot of extra junk to make > > that work? > > > > > > > > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>-- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
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