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
