I’m not sure it’s quite that simple. First, regulatory limits aside, I believe the PMP450 hardware is only capable of 22 dBm total (19 + 19). Second, it doesn’t change with modulation, while depending on which Ubiquiti radio you’re looking at, it probably changes with modulation. Third, with a 17 dBi antenna at the AP, you are only allowed 19 dBm total (16 + 16) in MIMO mode even under the old 15.247 rules because the EIRP is limited to +36 dBm. (CPE is considered PTP and allowed higher EIRP but that may now run into the 15.407 OOBE issue) So even under 15.247, you would only be able to use 27 dBm xmt power at the AP if your antenna gain was 9 dBi or less.
From: Chuck Hogg Sent: Tuesday, March 10, 2015 1:15 PM To: [email protected] Subject: Re: [AFMUG] More LTE tradgedy of the commons on 5 GHz.. That's a problem of the OOBE issue. Regards, Chuck On Tue, Mar 10, 2015 at 1:30 PM, Bill Prince <[email protected]> wrote: I also wonder with MIMO systems why the V/H or -45/+45 polarities are not considered separate transmitters (because they are). In which case each one should be allowed up to the limit? AND... What allows UBNT to transmit at up to 27 dbm, yet PMP450 is limited to 22 dbm? What's different there that I don't understand? 5 dbm is a bunch in my book. Is it OOB that is the issue here? bp <part15sbs{at}gmail{dot}com> On 3/10/2015 10:23 AM, Ken Hohhof wrote: Personally I also feel there is a flaw in the way EIRP is regulated on FHSS systems. The limit in 900 MHz is on total EIRP, not power spectral density. Somehow the FCC feels it is OK to concentrate 4 watts in one narrow hopping sub-channel as long as the dwell time isn’t too long. That’s like saying you can use a magnifying glass to concentrate sunlight on a single ant and it won’t hurt the ant as long as you move it to a different ant every second. No, you end up with a bunch of smoking ant carcasses on the sidewalk. Also the smartgrid mesh networks seem to violate the spirit of the requirement that you can’t get around the EIRP limit by using multiple transmitters to send the same data, for example in a MIMO system. From: Jeremy Grip Sent: Tuesday, March 10, 2015 12:10 PM To: [email protected] Subject: Re: [AFMUG] More LTE tradgedy of the commons on 5 GHz.. +1 From: Af [mailto:[email protected]] On Behalf Of Peter Kranz Sent: Tuesday, March 03, 2015 12:02 PM To: [email protected] Subject: Re: [AFMUG] More LTE tradgedy of the commons on 5 GHz.. I think the point some are missing is the lesson learned from 900Mhz and smart meters. While 900Mhz is unlicensed spectrum, a single operator has managed to take it over in California to the point where no other user has any chance of using the spectrum for commercial purposes. By this I mean that PG&E’s deployment of smart meters on every power meter in the area, and on top of power poles, and other high sites, has raised the noise floor on this band to unusable levels for high speed communications. So by means of overwhelming numbers, PG&E managed to take over 900Mhz for its own users, stranding the investment of ISPs in this spectrum in affected markets. I don’t think the commissions initial concept of unlicensed spectrum was that a single operator would do this, I think they expected operators by this to use licensed spectrum. I’d like to see a limit on how many systems a particular entity can deploy in an unlicensed band. It could be some high number, like 1 million units. Peter Kranz Founder/CEO - Unwired Ltd www.UnwiredLtd.com Desk: 510-868-1614 x100 Mobile: 510-207-0000 [email protected]
