airFiber (text of the 8 minute video)
owen at delong.com
Thu Mar 29 18:18:18 CDT 2012
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.
> 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.
> It also sounded like there was a decent possibility of supporting
> licensed 21 / 25 Ghz spectrum with AirFiber in the future.
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.
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