[151788] in North American Network Operators' Group
RE: airFiber (text of the 8 minute video)
daemon@ATHENA.MIT.EDU (Dylan Bouterse)
Fri Mar 30 18:31:53 2012
From: Dylan Bouterse <dylan@corp.power1.com>
To: "'nanog@nanog.org'" <nanog@nanog.org>
Date: Fri, 30 Mar 2012 22:31:18 +0000
In-Reply-To: <7F9D3BC0-A630-435F-A654-2E242730777C@delong.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
A couple of thoughts. First, it's not fair to compare 24GHz to 2.4 or even =
5Gig range due to the wave length. You will get 2.4GHz bleed through walls,=
windows, etc. VERY close to a 5GHz transmitter you may get some bleed thro=
ugh walls but not reliably. 24GHz will not propagate through objects as it'=
s millimeter wavelength. That coupled with the fact it is a directional PTP=
product, you will be able to get a good amount of density of 24GHz PTP lin=
ks using the same frequency in a small area (downtown for instance).
Another point, the GPS on the airFiber will also allow for frequency reuse =
to a point. I would like to see smaller channel sizes though. I hear it wil=
l be a software upgrade down the road. I'm shocked the old Canopy guys didn=
't code that into the first release to be honest.
Dylan
-----Original Message-----
From: Owen DeLong [mailto:owen@delong.com]=20
Sent: Thursday, March 29, 2012 7:18 PM
To: Oliver Garraux
Cc: NANOG list
Subject: Re: airFiber (text of the 8 minute video)
On Mar 29, 2012, at 12:33 PM, Oliver Garraux wrote:
>> Also keep in mind this is unlicensed gear (think unprotected airspace). =
Nothing stops everyone else in town from throwing one up and soon you're dr=
owning in a high noise floor and it goes slow or doesn't work at all. Like =
what's happened to 2.4GHz and 5.8GHz in a lot of places. There's few urban =
or semi-urban places where you still can use those frequencies for backhaul=
. The reason why people pay the big bucks for licenses and gear for license=
d frequencies is you're buying insurance it's going to work in the future.
>>=20
>> Greg
>=20
> I was at Ubiquiti's conference. I don't disagree with what you're
> saying. Ubiquiti's take on it seemed to be that 24 Ghz would likely
> never be used to the extent that 2.4 / 5.8 is. They are seeing 24 Ghz
> as only for backhaul - no connections to end users. I guess
> point-to-multipoint connections aren't permitted by the FCC for 24
> Ghz. AirFiber appears to be fairly highly directional. It needs to
> be though, as each link uses 100 Mhz, and there's only 250 Mhz
> available @ 24 Ghz.
>=20
> It also sounded like there was a decent possibility of supporting
> licensed 21 / 25 Ghz spectrum with AirFiber in the future.
>=20
> Oliver
I don't think it's an FCC issue so much as 24Ghz has so much fade tendency =
with atmospheric moisture that an omnidirectional antenna is about as effec=
tive as a resistor coupled to ground (i.e. dummy load).
The only way you can get a signal to go any real distance at that frequency=
is to use a highly directional high-gain antenna at both ends.
Owen
