Actually, modulation(s) / loading is a required data element of the PCN. The FCC application requires all modulations / bit rates to be listed, and they license these by polarization and direction so there is absolutely no need for “aggregate rates”. The FCC also requires a certification from the coordinator that the lowest compliant modulation (the lowest modulation that meets bits/Hz requirements) meets 99.95% two-way availability. The FCC doesn’t check this and instead leaves it up to the coordinator’s veracity and the coordination community to police. BTW, the bits/Hz requirement at 11 GHz is 3.0 bits/sec/Hz. 4.4 is the requirement at 6 GHz.
Unfortunately, there is at least one coordinator that routinely provides this certification when there’s no doubt at all it would be impossible to meet. I saw a recent path where the licensee was complaining on social media that he couldn’t get 10x or 1024 QAM. Well, no doubt as the path was coordinated and licensed with an RSL BELOW the 10-6 BER threshold for 1024Q. The lowest compliant modulation on this particular path was 256 QAM and the two-way availability calculated at something like 99.87% - and that was with the most liberal availability model (ITU-R). I know that the major coordinators are aware of this issue and have begun “policing” this to ensure that there’s a level playing field for all licensees and coordinators. Sent from my iPad > On Oct 10, 2018, at 1:28 PM, Ken Hohhof <af...@kwisp.com> wrote: > > I’m a bit annoyed that Liz puts “1.3 Gbps aggregate throughput” on the PCNs > she coordinates. It’s a nit, but a frequency coordinator should not be > influenced by marketing. I also suspect at least some customers think they > are getting the same capacity as other 80 MHz XPIC radios on the market. You > could say shame on them if they don’t realize that a true 1.3 Gbps requires 2 > gigabit Ethernet interfaces and LAG. If you go to the UBNT forums (dangerous > for your sanity), it’s clear that some of the fanboys really believe the AF11 > kicks everybody else’s butt when it comes to spectral efficiency and maximum > modulation. It is an innovative and cost effective product with some nice > features like swappable diplexers and XPIC included at no extra cost, but it > isn’t kicking any butt on efficiency or modulation level, in fact it seems to > trade those off to get the cost down. > > Back to the PCNs, it’s probably not important for the bulk of AF11 links, > which are short. But if someone is doing a 10+ mile link, I suspect the AF11 > may not actually meet FCC capacity requirements. I forget the exact numbers, > but it’s something like 4.4 bits/sec/Hz, 99.95% of the time with rain fade. > So with a 160 MHz allocation (2x80 MHz XPIC), if the requirement is actually > 4.4 bits/sec/Hz, that would be 704 Mbps, which is right about what the AF11 > can do at full modulation on a sunny day. Not totally sure I have those > numbers right, and I don’t think anyone actually checks it anyway. It just > bothers me to see a PCN going out of its way to parrot the manufacturer’s non > standard way of quoting capacity. I’m not sure a PCN even needs to state > capacity, so I’m not sure why Liz is doing this. > > > From: AF <af-boun...@af.afmug.com> On Behalf Of Adam Moffett > Sent: Wednesday, October 10, 2018 11:26 AM > To: af@af.afmug.com > Subject: Re: [AFMUG] Bridgewave Navigator > > I bitched at length about Ubiquiti's claims for AF11 in the past. > > The thing I realized is that while their spec sheet numbers are inconsistent > with the rest of the industry, they're consistent with the rest of the > Ubiquiti ecosystem. They've chosen to be self consistent. I still think > they're wrong, but I'm not mad anymore. > > -Adam > > > > On 10/10/2018 12:05 PM, Ken Hohhof wrote: > One worry of course is that if someone can’t coordinate a link due to your > use of Cat B antennas, they can force you to upgrade to Cat A. I’m not > saying I’ve worried a lot about that, but I would worry more if I was in a > more urban area. > > Re-using antennas sometimes works, it depends on the manufacturers, and you > probably need to buy adapters. And re-coordinate the link of course for the > new radios. I just finished changing an 11 GHz single pol Trango link to > dual pol PTP820C, and the adapters worked fine. I will probably have to > re-do a couple Exalt G2 links if only because Exalt seems to be defunct. But > in the Trango and Exalt cases, those links have been in place around 5 years. > In practice, I don’t think you end up putting in a cheap link and then > upgrading it in 1-2 years. Those links are going to be with you for 3-5 > years, maybe more if they are doing the job just fine. Meanwhile you may > upgrade your PtMP equipment on those towers multiple times, new batteries, > new routers, but the licensed links just keep on doing their job. > > Please realize that any change to the radios or antennas requires a frequency > coordinator fee and a license modification fee, even if you stay on the same > channels. > > If you select antennas with coax connectors, that will further limit what > radios will work with them. I don’t like that trend, and I don’t see how it > will extend to 18 or 23 GHz since you already need special N connectors at 11 > GHz. I also don’t like what Ubiquiti is doing with the AF11 radios, > advertising them as 1.3 GHz “aggregate” when everybody else in the industry > advertises one-way throughput. They are not spectrally efficient radios, > plus I don’t believe they can do a true 80 MHz channel. I guess the good > news is that your license has basically locked up channels for 80 MHz CCDP, > so even though you will have to re-do coordination and modify your license, > you are probably guaranteed being able to use those frequencies for a higher > throughput more expensive radio in the future (as long as it can do XPIC, > which might involve paying for a key to unlock the feature.) > > > From: AF <af-boun...@af.afmug.com> On Behalf Of Mathew Howard > Sent: Wednesday, October 10, 2018 10:17 AM > To: AFMUG <af@af.afmug.com> > Subject: Re: [AFMUG] Bridgewave Navigator > > Yeah, but the thing about not cheaping out is that you can buy link now for > $4k that you would have had to spend closer to $20k for the equivalent of not > that many years ago... of course that doesn't really apply to antennas, since > you should be able to re-use the same dish in most cases. > > On Wed, Oct 10, 2018 at 9:50 AM Ken Hohhof <af...@kwisp.com> wrote: > My gut tells me 2 conflicting things about licensed links. > > On the one hand, I've learned over time not to cheap out on them. They are > critical infrastructure that last for years and require minimal attention > after the initial design and build. Do it right the first time, and plan > them for 5+ years down the road, not just next month. > > But on the other hand, we are being forced toward the fixed wireless version > of "small cells". We need max modulation on every subscriber, and even so, > to support peak time video streaming and 25-100 Mbps speeds, we are limited > to as little as 10 subscribers on an AP. So we need more towers, close to > customers, and with fewer customers per tower. The math doesn't add up if > you have a couple $10K links at a tower that only serves maybe 20 customers > total. So there will be a demand for cheaper radios and antennas. Thinking > we can do all these gigabit links in unlicensed is unrealistic. > > > -----Original Message----- > From: AF <af-boun...@af.afmug.com> On Behalf Of Seth Mattinen > Sent: Wednesday, October 10, 2018 9:05 AM > To: af@af.afmug.com > Subject: Re: [AFMUG] Bridgewave Navigator > > On 10/10/18 5:20 AM, Tim Hardy wrote: > > 160 MHz Bw not legal in the US and would require rule waivers if the > > channel pairs were available. Bear in-mind that the Jirous antennas > > used on a lot of UBNT and Mimosa paths are only Cat B and don’t lend > > themselves to a lot of frequency reuse. Even the Cat A antennas (3’ - > > Commscope, RadioWaves, RFS) aren’t that great (Commscope’s Sentinel > > and RFS’ SC are better). There’s a reason why many of the Cellular > > and Public Safety systems use 4 or 6 foot shrouded high performance or > > ultra-high performance antennas.. > > > Anyone using a UBNT or Mimosa probably don't want to pay for (or can't > afford) a Class 4 Sentinel. > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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