From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp65.iad3a.emailsrvr.com (smtp65.iad3a.emailsrvr.com [173.203.187.65]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id EEC7B21F40B for ; Sat, 20 Dec 2014 18:37:45 -0800 (PST) Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp17.relay.iad3a.emailsrvr.com (SMTP Server) with ESMTP id D5C4B180109; Sat, 20 Dec 2014 21:37:43 -0500 (EST) X-Virus-Scanned: OK Received: by smtp17.relay.iad3a.emailsrvr.com (Authenticated sender: dpreed-AT-reed.com) with ESMTPSA id 55DFC180105; Sat, 20 Dec 2014 21:37:43 -0500 (EST) X-Sender-Id: dpreed@reed.com Received: from [100.89.240.116] (18.sub-70-192-10.myvzw.com [70.192.10.18]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA) by 0.0.0.0:465 (trex/5.4.2); Sun, 21 Dec 2014 02:37:43 GMT User-Agent: K-@ Mail for Android X-Priority: 3 In-Reply-To: <6764.1419109075@ccr.org> References: <6764.1419109075@ccr.org> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----85NXGE71DXYN9L9MHXL5N9I6K1R5Q8" Content-Transfer-Encoding: 7bit From: "David P. Reed" Date: Sat, 20 Dec 2014 21:37:41 -0500 To: Mike O'Dell ,cerowrt-devel@lists.bufferbloat.net Message-ID: <68a9aec2-9a5e-4cc0-84d1-3fce8ccc0efb@reed.com> Subject: Re: [Cerowrt-devel] Cerowrt-devel Digest, Vol 37, Issue 24 X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Dec 2014 02:38:14 -0000 ------85NXGE71DXYN9L9MHXL5N9I6K1R5Q8 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Neither 2=2E4 GHZ nor 5=2E8 GHz are absorbed more than other bands=2E That'= s an old wives tale=2E The reason for the bands' selection is that they wer= e available at the time=2E The water absorption peak frequency is 10x highe= r=2E Don't believe what people repeat without checking=2E The understandin= g of radio propagation by CS and EE folks is pitiful=2E Some even seem to t= hink that RF energy travels less far the higher the frequency=2E Please do= n't repeat nonsense=2E On Dec 20, 2014, Mike O'Dell wrote: = >15=2E9bps/Hz is unlikely to be using simple phase encoding > >that sounds = more like 64QAM with FEC=2E >given the chips available these days for DTV, = DBS, >and even LTE, that kind of processing is available >off-the-shelf (re= latively speaking - compared to >writing your own DSP code)=2E > >keep in = mind that the reason the 2=2E4 and 5=2E8 ISM bands >are where they are is s= pecifically because of the ready >absorption of RF at those frequencies=2E = the propagation >is *intended* to be problematic=2E that said, with >good-= enough antennas mounted with sufficient stability >and sufficient power on = the TX end and a good enough >noise floor on the RX end, one can push a bun= ch of bits >pretty far=2E > >Bdale Garbee (of Debian fame) had a 10GHz bent= -pipe repeater >up on the mountain above Colo Spgs for quite some time=2E = X-band >Gunnplexers were not hard to come by and retune for the >10GHz ham = band=2E i believe he just FM'ed the Gunnplexer >with the output of a 10Mbps= ethernet chip and ran >essentially pure Aloha=2E X-band dishes are relativ= ely >small and with just a few stations in the area he had fun=2E > > = -mo >_______________________________________________ >Cerowrt-devel mailin= g list >Cerowrt-devel@lists=2Ebufferbloat=2Enet >https://lists=2Ebufferbloa= t=2Enet/listinfo/cerowrt-devel -- Sent from my Android device with K-@ Mai= l=2E Please excuse my brevity=2E ------85NXGE71DXYN9L9MHXL5N9I6K1R5Q8 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable Neither 2=2E4 GHZ nor 5=2E8 GHz are absorbed more = than other bands=2E That's an old wives tale=2E The reason for the bands' s= election is that they were available at the time=2E The water absorption pe= ak frequency is 10x higher=2E

Don't = believe what people repeat without checking=2E The understanding of radio p= ropagation by CS and EE folks is pitiful=2E Some even seem to think that RF= energy travels less far the higher the frequency=2E
Please don't repeat nonsense=2E

On Dec 20, 2014, Mike O'Dell <mo@c= cr=2Eorg> wrote:
15=2E9bps/Hz is unlikely to be using simple pha=
se encoding

that sounds more like 64QA=
M with FEC=2E
given the chips available these days for DT=
V, DBS,
and even LTE, that kind of processing is availabl=
e
off-the-shelf (relatively speaking - compared to 
writing your own DSP code)=2E

keep in mind that the reason the 2=2E4 and 5=2E8 ISM bands
are where they are is specifically because of the ready
absorption of RF at those frequencies=2E the propagation
is *intended* to be problematic=2E that said, with 
good-enough antennas mounted with sufficient stability
a=
nd sufficient power on the TX end and a good enough
noise=
 floor on the RX end, one can push a bunch of bits
pretty=
 far=2E

Bdale Garbee (of Debian fame) =
had a 10GHz bent-pipe repeater 
up on the mountain above =
Colo Spgs for quite some time=2E X-band
Gunnplexers were =
not hard to come by and retune for the
10GHz ham band=2E =
i believe he just FM'ed the Gunnplexer
with the output of=
 a 10Mbps ethernet chip and ran
essentially pure Aloha=2E=
 X-band dishes are relatively 
small and with just a few =
stations in the area he had fun=2E

-mo=

Cerowrt-devel mailing list<= br clear=3D"none">Cerowrt-devel@lists=2Ebufferbloat=2Enet
https://lists=2Ebufferbloat=2Enet/listinfo/cerowrt-devel

-- Sent from my Android= device with K-@ Mail=2E Pleas= e excuse my brevity=2E ------85NXGE71DXYN9L9MHXL5N9I6K1R5Q8--