On Mon, Apr 27, 2009 at 07:59:07PM -0400, Chris Knadle wrote: > You're probably right, but 3 dB means double the gain of 0 dB, so 2 dB > isn't nothing. The standard spherical radiation pattern of 0dB gain > is called "isotropic"; 2 dB = 2dBi, both mean "2dB over isotropic". > I would have preferred if they had named it "spherical" because that > gets the idea across better, but unfortunately most of the antenna > mathematics were developed by physicists rather than engineers, which > explains why the terminology and methodology is a bit backwards in > some respects.
Yes, but in practical terms, I've never seen a 2dB omni on an AP cause a dead spot. Until you pass about 5dB on an omni at 2.4ghz you're not going to fall out of the vertical range quickly. The antennas shipped with the AP are designed to provide maximum coverage with moderate gain. > > So, simply put, don't go hacking up the antennas on your 11n AP. > > You probably won't appreciate the results. > > That's probably good advice. At the same time, though, it is possible > to make dual-band antennas, at least in general. You can usually tell > whether a monopole is a dual-band monopole if there's a loading coil > at about the midway point of the antenna whip. Possible, yes, practical, not particularly, and far afield of his original question of "how to I move my network so I get more coverage". 2.4ghz is at the edge of being too finicky for someone at home to solder up (all the tutorials on making your own antenna aside, since the major of those are complete crap). > I know they sell aftermarket replacement 802.11 antennas with higher > gain, but I haven't looked to see if they sell aftermarket ones for > 802.11n. They don't, infact I know of no 11n consumer gear which has replaceable antennas; precisely because replacing them with mismatched antennas (or even just different gain) would significantly confuse the MIMO stuff. -m -- Mike Kershaw/Dragorn <[email protected]> GPG Fingerprint: 3546 89DF 3C9D ED80 3381 A661 D7B2 8822 738B BDB1 Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam. I have a catapult. Give me all your money, or I will fling an enormous rock at your head
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