

Bold plan: opening 1,000 MHz of federal spectrum to WiFi-style sharing - boh
http://arstechnica.com/information-technology/2012/07/bold-plan-opening-1000-mhz-of-federal-spectrum-to-wifi-style-sharing/

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th0ma5
Beyond merely the frequencies themselves, there's a ton of logistics involved
in things like harmonic or other interference and propagation, all of this
related to power. However, it is increasingly such that a lot of devices are
software-based radios, so changes to a lot of existing technology could be
just a firmware upgrade, if possible.

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pbsurf
Unfortunately, we are not yet at the point where a range of frequencies
anywhere near as wide as discussed in the article can be supported by a simple
firmware upgrade. RF receivers typically include a very narrow bandpass filter
as the first component after the antenna. As spectrum becomes more crowded,
these filters are even more critical to prevent saturation of the low-noise
amplifier and unwanted products from the downconverter/mixer.

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CamperBob2
_RF receivers typically include a very narrow bandpass filter as the first
component after the antenna_

Historically true, but as ADCs get better (and more important, cheaper), that
will be less and less common.

Software-defined radios with broadband front ends don't play by the same IMD
rules as conventional radios, anyway.

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patrickyeon
In my experience, the ADC is far from the limiting factor for linearity in an
SDR receiver. The analog components up front (LNA and mixer, especially) are
the limiting components. Broadband front ends make it even worse, because it's
more likely you'll have an interferer passed through the filtering, even if
it's nowhere near (in frequency) your signal.

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Nrsolis
Don't forget the antenna. In many cases, the antennas themselves have specific
polarization and beamwidth/radiation patterns along with SWR that is directly
tied to the frequency range of the antenna itself. SDR doesn't change any of
this.

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jakeonthemove
That's a pretty good idea: it's like public roads: normally, they're used by
the citizens, but if there's a VIP guest or a military situation, the
government can clear and use them for themselves only. Makes sense to do the
same with frequencies (although it will be a bit harder to manage - like the
EBS test in 1971 has shown)...

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w-ll
I worked on the first USA test of White Space WiFi up till last year. Pretty
cool stuff, smart engineers. Right now it's being utilized for public services
(cops, firemen, highway cams... a few other things that were a little more
interesting but... NDA'd)

It's great to see more initiative on rolling out this technology.

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dusing
Anyone know what kind of speeds could go over these frequencies?

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a1k0n
The Shannon limit would be at most 2Gbps...

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juiceandjuice
Based on what?! OP's question wasn't very well defined and your answer is
completely arbitrary.

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gringomorcego
2.2GBPS

