[151736] in North American Network Operators' Group
Re: airFiber (text of the 8 minute video)
daemon@ATHENA.MIT.EDU (Owen DeLong)
Thu Mar 29 19:22:56 2012
From: Owen DeLong <owen@delong.com>
In-Reply-To: <CAD_uLpO4NFWXUGmCxBs-JE+bK1aaBns3qr=jVTC_r1o0_6zXew@mail.gmail.com>
Date: Thu, 29 Mar 2012 16:18:18 -0700
To: Oliver Garraux <oliver@g.garraux.net>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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 drowning 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 licensed 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 effective 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
