If space is no problem it is very easy to do low cost high performance waveguide filters at these frequencies.
From: Ken Hohhof Sent: Tuesday, February 26, 2019 4:23 PM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Higher power 18Ghz radios.. If you’re referring to AF11, isn’t that an OFDM platform? Which is an unusual choice for a licensed radio, most are single carrier QAM. OFDM lets you implement with a DSP approach and naturally gives you a power spectral density plot that looks like “Bart’s head”. It naturally yields a certain amount of out-of-band filtering, probably saving money. But then to meet a rigorous OOB emissions template, now you need additional analog filtering which eats into the cost savings. Especially at 11 GHz where I assume you aren’t just throwing in a few inductors and capacitors to create a brick wall filter. From: AF <[email protected]> On Behalf Of Tim Hardy Sent: Tuesday, February 26, 2019 4:23 PM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] Higher power 18Ghz radios.. Sloppy filters. Sent from my iPad On Feb 26, 2019, at 5:18 PM, Mathew Howard <[email protected]> wrote: Well, I'm just guessing, but what other reason would there be for occupying 79mhz with a 56mhz radio? On Tue, Feb 26, 2019 at 4:08 PM Tim Hardy <[email protected]> wrote: If that’s the case, it must’ve been truly horrid at 56 MHz. There are consequences in this wasting of spectrum - you’ll notice that modulations less than 16 QAM are not currently coordinated or licensed since they fail to meet the FCC’s minimum of 1 bit/Hz. Any operation of the AF-11 at QPSK or 1/4 QPSK is not actually legal.. Sent from my iPad On Feb 26, 2019, at 4:34 PM, Mathew Howard <[email protected]> wrote: Yeah, but my point is that they made a really noisy 56mhz radio work by just occupying a full 80mhz channel... at least that's the way I understand it. It seems like they're kind of doing the same thing here. On Tue, Feb 26, 2019 at 3:24 PM Tim Hardy <[email protected]> wrote: While the AF-11 used a 56 MHz chipset, the radio occupies 79.6 MHz - unlike all other radios with these chips that limit their bw to 56 MHz (this used to be the ETSI maximum). The AF-11 system gain is horrible for 1024 QAM when compared to other outdoor radios - either full 60 MHz or full 80 MHz bw. Sent from my iPad On Feb 26, 2019, at 3:26 PM, Mathew Howard <[email protected]> wrote: Interesting, so I'm guessing that they're able to reduce the noise to an acceptable level at that high of power by using a narrower channel... kind of like what Ubiquiti did with the AirFiber 11. On Tue, Feb 26, 2019 at 1:54 PM Tim Hardy <[email protected]> wrote: Just an FYI.. According to this chart, the occupied bandwidth is only 64.5 MHz so you will be losing capacity vs radios that occupy the full 80 MHz bandwidth. The DW radio will have to be coordinated and licensed in one of the 80 MHz channel allocations as there are no FCC channel plans between 51 MHz and 79 MHz. There are only 4-channel pairs available at 80 MHz and its difficult to coordinate multiple pairs in many areas as a result. Finally, while these power levels are impressive, they don't tell the full story and you really need to compare the system gain values at the desired modulations. The DW 64.5 MHz radio’s system gain at 2048 QAM is 83 dB vs. the WTM 4100 80 MHz radio’s system gain at 2048 QAM which will be 73.5 dB. On Feb 26, 2019, at 12:19 PM, Peter Kranz <[email protected]> wrote: +31 is the advertised 2048QAM output on the HP variant. Dragonwave contacted me offline and is indicating a March availability. Here is the table of power output levels for that radio. It should also support 4096QAM, but I’m not sure if that’s available in the software yet. <image001.png> Peter Kranz www.UnwiredLtd.com Desk: 510-868-1614 x100 Mobile: 510-207-0000 [email protected] From: AF <[email protected]> On Behalf Of Ken Hohhof Sent: Monday, February 25, 2019 8:27 PM To: 'AnimalFarm Microwave Users Group' <[email protected]> Subject: Re: [AFMUG] Higher power 18Ghz radios.. Looks like PTP820c is only +16. You’re talking about xmt power actually at 2048QAM modulation, right? +31 is hard to believe. I remember hearing that Broadcom was supposed to have a chip with adaptive digital predistortion for high xmt power also 4096QAM not sure if that became real. From: AF <[email protected]> On Behalf Of Peter Kranz Sent: Monday, February 25, 2019 6:51 PM To: [email protected] Subject: [AFMUG] Higher power 18Ghz radios.. Dragonwave announced over a year ago the Harmony Enhanced 18HP, with +31 TX power at 2048 QAM, but have never made it to production as far as I know. From the top of my head, here are some of the major radios TX power in 18 Ghz band: Dragonwave Harmony Enahcend HP – 31 <Vaporware?> Dragonwave Harmony Enhanced SP – 22 Bridgewave Navigator – 19 Aviat WTM 4200 – 17.5 SIAE AlfoPlus2 – 17 Curious if anyone is aware of an 18Ghz dual core radio capable of higher TX power at 2048QAM? It’s quite difficult to license 6Ghz or 11Ghz paths in my market. 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