[163052] in North American Network Operators' Group
Re: 40 GBit @ 240 GHz across 1 km LoS
daemon@ATHENA.MIT.EDU (Warren Bailey)
Fri May 17 13:33:30 2013
From: Warren Bailey <wbailey@satelliteintelligencegroup.com>
To: Phil Fagan <philfagan@gmail.com>
Date: Fri, 17 May 2013 17:33:14 +0000
In-Reply-To: <CAPhg-wRX6u95MKhfnjrEuAeep2vhjaqTM1a3jV+Za6bSRKv+jQ@mail.gmail.com>
Cc: NANOG list <nanog@nanog.org>
Reply-To: Warren Bailey <wbailey@satelliteintelligencegroup.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Super high frequency stuff is already in space. Iridium uses ka for their s=
pace craft to space craft routing network. Not much attenuation in a vacuum=
.. ;)
Look up vortex beams. These guys should hook up with the vortex guys. They =
were getting like 40bits to hertz using oam.
Sent from my Mobile Device.
-------- Original message --------
From: Phil Fagan <philfagan@gmail.com>
Date: 05/17/2013 10:29 AM (GMT-08:00)
To: Warren Bailey <wbailey@satelliteintelligencegroup.com>
Cc: Carsten Bormann <cabo@tzi.org>,NANOG list <nanog@nanog.org>
Subject: Re: 40 GBit @ 240 GHz across 1 km LoS
Well put; 1kM is a giant leap from .1Km, but its a far cry from rural trans=
port.
I wonder what the fixed mobile/metro use cases might look like; Alternate p=
ath, aggregate short distance media backhaul...
I think I like the idea most for non-earth atmosphere use cases, space vehi=
cle or exploration vehicle use.
Can you blast your way through rain, snow, or hell...a sandstorm by increas=
ing your power?
On Fri, May 17, 2013 at 10:44 AM, Warren Bailey <wbailey@satelliteintellige=
ncegroup.com<mailto:wbailey@satelliteintelligencegroup.com>> wrote:
I disagree.
It's not the near field stuff that is an issue.. It's the far field stuff
further down the road that is going to murder the link.. Look at his Fig 1
and Fig 2.
Fig 1 is saying that he is getting killed at 50mm/h of rain at 60 gig and
at 175 gig. Fig 2 is saying that everything works well until you exceed
.1km - where real life kicks back in. His clear sky is normal for anything
wireless, but look at what happens at distances exceeding his comfort
zone. From .1km to 1km he's taking 30-50dB of loss on his link. I don't
know what kind of transmitter he has, but *IF* he were to encounter rain I
sure as hell hope he has a form of transmit power control. I also noticed
that they're using OOK, which is much better than FSK but runs the risk of
being clobbered by a relatively small amount of noise.
So yes, this is awesome for running huge data rates across the street.
Down the road, you may have a few bad days.
On 5/17/13 8:22 AM, "Carsten Bormann" <cabo@tzi.org<mailto:cabo@tzi.org>> w=
rote:
>On May 17, 2013, at 16:30, Warren Bailey
><wbailey@satelliteintelligencegroup.com<mailto:wbailey@satelliteintelligen=
cegroup.com>> wrote:
>
>> By not working. At those frequencies you're talking a light moisture
>>pocket taking the entire link down.
>
>Not quite as bad:
>
>http://www.uni-stuttgart.de/int/institut/MA_Publikationen/reichart/COMCAS_
>25G_link.pdf
>
>The ~ 50 mm/h rain they seem to budget for is not yet quite an "end of
>the world" torrent, but it's not like you sneeze and the link goes down.
>(And if you have more than 50 mm/h sustained, you've got a much, much
>bigger problem :-)
>
>Gr??e, Carsten
>
--
Phil Fagan
Denver, CO
970-480-7618
