On Feb 17, 2013, at 4:17 PM, joel jaeggli <joe...@bogus.com> wrote: > On 2/17/13 12:18 PM, Jay Ashworth wrote: >> ----- Original Message ----- >>> From: "Owen DeLong" <o...@delong.com> >>> I think by A you actually mean 5Ghz N. A doesn't do much better than G, >>> though >>> you still have the advantage of wider channels and less frequency congestion >>> with other uses. >> No, my ThinkPad doesn't *do* N, 5GHz or otherwise. Neither does my Sprint >> EVO, nor, as near as I can tell, the Galaxy S4 I'm going to replace it >> with this year (though on that one, I'm a tad less certain). >> >> I'd forgotten that N was dual band, though, yes. I can't say I've ever >> needed the extra bandwidth N provides, personally, though certainly the >> hotels we've been discussing might need more to share around. > entirely orthonal to the frequency band used spatial division multipluxing as > used by 802.11n is generally going to increase the SNR. > > so what you get out of A/N is: > > * more non-overlapping bands and therefore a much easier map coloring problem) > * greater attenuation, which implies more limited range, but also less > interferance.
Greater attenuation is an oversimplification. 5Ghz penetrates things like stucco and concrete better than 2.4. OTOH, 2.4 gets through trees and moist air better. In dry air and/or a vacuum, they're similar. Neither penetrates humans particularly well, though 5 tends to do slightly better. > * with N-mimo higher SNR if you have >= 2 antennas > > All of those things make the 5Ghz band a more attractive alternative for lots > of applications. given that it's 5Ghz it also requires more power, which is a > problem for cellphones, but not so much for tablets and laptops. OTOH, with 5Ghz, a high-gain antenna is ½ - ⅛ the size (depending on the type of antenna) the size of a 2.4Ghz which also has advantages in portable applications. Owen
