And they're both stronger than a WAG. Lots of people don't understand the "scientific method", or how science differs from religion or faith. Science is based on usefulness, how well it can explain observations and make predictions. Quantum mechanics didn't prove Newtonian mechanics wrong or destroy anyone's faith. Scientists thought cool, a new theory that explains and predicts more things. But Newton is still very useful unless you live next to a black hole. Or want to build a nuke.
-----Original Message----- From: AF <af-boun...@af.afmug.com> On Behalf Of Adam Moffett Sent: Tuesday, June 23, 2020 1:33 PM To: af@af.afmug.com Subject: Re: [AFMUG] TVWS feasibility In this case you could call it a law because it's nothing more than a formally stated observation. A theory tries to explain why things happen, a law is just stating what happens. One isn't better or stronger; they're just different things. A "theory" about why gravity works is different from the direct observational "law" of gravitational attraction attested by Isaac Newton. Maybe everyone here knows that already, but a lot of people were never told and just make an assumption based on the literal words. </OT> On 6/23/2020 12:08 PM, Ken Hohhof wrote: > I was actually repeating your advice from past threads. Maybe we can > call it "McCown's Theorem". > > Nope, better make that "McCown's Law". The anti-science segment of > society takes the word "theorem" to mean "unsubstantiated nonsense". > > -----Original Message----- > From: AF <af-boun...@af.afmug.com> On Behalf Of ch...@wbmfg.com > Sent: Tuesday, June 23, 2020 10:46 AM > To: 'AnimalFarm Microwave Users Group' <af@af.afmug.com> > Subject: Re: [AFMUG] TVWS feasibility > > I calculated it once. Always good to go up in frequency if antenna > gain and path loss are the only considerations. > > If you increase the frequency, it works out that the system margin > increases by the increase of gain of one of the antennas assuming > identical antennas at both ends. > > -----Original Message----- > From: Ken Hohhof > Sent: Tuesday, June 23, 2020 9:21 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] TVWS feasibility > > Lower frequencies do have lower free space loss, but for the same size > antenna you have less antenna gain. And with 2 antennas (xmt and > rcv), antenna gain wins. All else being equal, higher frequency > usually wins. Of course with TVWS you usually accept using ginormous > antennas. > > I think people are telling you that TVWS is a niche technology, one > that isn't even a clear winner in its niche, and shouldn't be used > outside its niche. If you have clear LOS, use something else. If you > have 99 NLOS customers and 1 who happens to have LOS, I guess you > could put him on the TVWS system too. > > > -----Original Message----- > From: AF <af-boun...@af.afmug.com> On Behalf Of D. Bernardi > Sent: Tuesday, June 23, 2020 10:09 AM > To: AnimalFarm Microwave Users Group <af@af.afmug.com> > Subject: Re: [AFMUG] TVWS feasibility > > > > Clearly RF isn't my specialty... Instead of SNR I guess I really meant > noise. If the noise floor is equal wouldn't there be less attenuation > of the signal in an open environment (resulting in a better SNR)? > > > > At 10:41 AM 6/23/2020, you wrote: > >>> On Jun 23, 2020, at 10:32 AM, D. Bernardi <dberna...@zitomedia.net> > wrote: >>> >>> >>> I was thinking more in terms of foliage or other object density, >> or mountains/hills, to help estimate range. Wouldn't TVWS still have >> better performance in an open area compared to dense forest given >> equal SNR? >> If SNR is identical then you will get identical performance, >> assuming the same channel size and modulation. TVWS channel size >> is considerably smaller than the higher frequency alternatives and >> has lower modulation levels (at least that I have seen). >> >> Mark >> -- >> 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 > > -- 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
