So, am I understanding correctly... If you are on a 50MHz Channel BW with a signal of -58 you need a noise floor of -97 to maintain 1024QAM. So, if the noise floor is -75 we are 22db off so you can add that to -58 and figure -80, or QPSK. Is this the correct math?
On Mon, Jan 12, 2015 at 8:44 PM, Chuck Macenski <ch...@macenski.com> wrote: > Hi, > > I believe the number you are looking for is the sensitivity per modulation > rate minus the base noise floor for a given bandwidth (see Matt's earlier > post). This gives you the required signal over the noise floor. If the > noise floor goes up, the effective sensitivity goes up accordingly. > > What am I missing? > > Chuck > > On Mon, Jan 12, 2015 at 5:23 PM, Josh Reynolds <j...@spitwspots.com> > wrote: > >> This. >> >> josh reynolds :: chief information officer >> spitwspots :: www.spitwspots.com >> >> On 01/12/2015 11:00 AM, Mike Hammett wrote: >> >> Matt, that doesn't really help. >> >> In many areas, my noise/interference/whatever is -75. If I knew how much >> margin was required per modulation, I could figure out how much signal I >> need for that speed. >> >> I can't do that with your published numbers. >> >> >> >> ----- >> Mike Hammett >> Intelligent Computing Solutionshttp://www.ics-il.com >> >> ----- Original Message ----- >> From: Matt Hardy <m...@ubnt.com> <m...@ubnt.com> >> To: af@afmug.com >> Sent: Mon, 12 Jan 2015 12:42:52 -0600 (CST) >> Subject: Re: [AFMUG] Af5 >> >> Hi Mike, >> The numbers in our datasheet do convey the SNR (which assumes AWGN for >> noise value); this is pretty standard among all our datasheets. >> The noise floor value varies based on channel BW, so a rough estimate for >> noise floor would be (50MHz=-97dBm, 40=-98dBm, 30=-99dBm, 20=-101dBm, >> 10=-104dBm). >> >> As far as transmit power / modulation, all modulations up to 64QAM can run >> at full transmit power. 256QAM is ~2dB lower, and 1024QAM is something like >> 4dB lower (it depends on other external factors). >> >> All of this and more is already provided with the integrated link >> configuration tool, including channel bandwidth, duplex frequency spacing, >> TX power and a bunch of other stuff. It's recommended to use this tool to >> configure links because of all of the additional factors. >> >> But if you need to run a simple link calc to estimate a link's performance >> at certain distance, you should have enough info. >> >> Hope that helps... >> >> -Matt >> >> >> On Sat, Jan 10, 2015 at 10:06 AM, Mike Hammett <af...@ics-il.net> >> <af...@ics-il.net> wrote: >> >> >> Not at all, Matt. Those are receive sensitivities. >> >> >> The left side of this picture is needed for the airFibers. You publish the >> right side only. >> >> >> This information is also not available for the airFibers. >> >> >> >> ----- >> Mike Hammett >> Intelligent Computing Solutionshttp://www.ics-il.com >> >> ------------------------------ >> *From: *"Matt Hardy" <m...@ubnt.com> <m...@ubnt.com> >> *To: *af@afmug.com >> *Sent: *Friday, January 9, 2015 5:34:43 PM >> *Subject: *Re: [AFMUG] Af5 >> >> This? >> [image: Inline image 1] >> >> On Thu, Jan 8, 2015 at 5:18 PM, Mike Hammett <af...@ics-il.net> >> <af...@ics-il.net> wrote: >> >> >> Hard to tell because they won't publish their Tx and SNR requirements. >> I'd just make educated guesses and plug it into a path calc. >> >> BTW: Ben, Matt... where are those numbers? >> >> >> >> ----- >> Mike Hammett >> Intelligent Computing Solutionshttp://www.ics-il.com >> >> ------------------------------ >> *From: *"Craig House" <cr...@totalhighspeed.net> <cr...@totalhighspeed.net> >> *To: *af@afmug.com >> *Sent: *Thursday, January 8, 2015 3:24:58 PM >> *Subject: *[AFMUG] Af5 >> >> I have used some AF 24 hours but no AF5 for backhaul yet what is the max >> distance people are seeing for the AF 5 at full modulation >> >> Sent from my iPhone >> >> >> >> >> >
