Date: Thu, 8 Sep 2011 11:14:38 +0200 From: Berislav Purgar <bpurgar@gmail.com> To: Lev Serebryakov <lev@freebsd.org> Cc: freebsd-wireless@freebsd.org Subject: Re: AP performance (again): txpower regulation Message-ID: <CAAUsrB5Qtokpcz-koUfYWCHrsnUUErQSAYHrXrW2F0Uvp3RzSA@mail.gmail.com> In-Reply-To: <426917282.20110908125907@serebryakov.spb.ru> References: <663133681.20110907193747@serebryakov.spb.ru> <CAJ-Vmonai4LzwanLw7i5d-NyjN2b6GqfttjkdcROvOuEcuzEAw@mail.gmail.com> <437702009.20110907235248@serebryakov.spb.ru> <CAJ-Vmo=R-a%2BqhDLWj1n%2BBj70Pmg4WSL6bVZ6jwCUmNq=v7EBBw@mail.gmail.com> <426917282.20110908125907@serebryakov.spb.ru>
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2011/9/8 Lev Serebryakov <lev@freebsd.org> > Hello, Adrian. > You wrote 8 =D1=81=D0=B5=D0=BD=D1=82=D1=8F=D0=B1=D1=80=D1=8F 2011 =D0=B3.= , 8:02:28: > > > These look fine, but I don't have as much experience with the ar5212 > > series stuff as I do with the AR5416+ series stuff. > >> It seems, registers are Ok. But clients don't see any difference! > >> Maybe, it is because my Senao card is "powerful" one, with additional > >> schematic (and power supply) to boost signal? > > > Hm. Well, how far away are they? You can do a bit of math to see what > About 7 meters and 2 concrete (internal) walls :) > > I've repeated experiment when client and server were within 3 meters > without walls -- txpower seems to work. 30 gives about -55dB > (accroding to InSSIDer -- I'm not sure, that this numbers could be > used as absolute ones),txpower 15 gives about -65 and txpower 1 about > -75. > > But in any case iperf throughput is about 10-11Mbit/s with pikes up to > 18Mbit/s. > > It looks pessimistic: 18Mbit/s in 2m direct sight. I know, that > 54Mbit/s is half-duplex, but 18Mbit/s is less than 27Mbit/s and > "ifconfig wlan0 list sta" shows data like this: > > 00:18:de:08:e8:1d 1 9 36M 21.5 0 28696 48048 EPS AQE RS= N > WME > > Why 36M in almost-ideal conditions!? Why -70dB in room next to my AP, > when neighborhood AP (simple d-link, according to all data) is -65, > and this room is furthest from other apartments)!? > > Also, graph of signal strength is much smoother on small distances and > didn't look like mountain range. > > Another observation: when distance is about 5 meters txpower 30, 15 and > 10 are almost indistinguishable (and grpahs are smooth, -75dB for 10, > -70dB for 15, -67dB for 30), but txpower 1 gives crazy graph: it > osscilate between -80 and -10 (!!!). Sometimes it gold on -77, but > after 10-15 seconds raise to the sky, then drop down again, etc. > > > changes the TX power on the sender side would have on the receiver > > signal level. > > Have you ever looked at doing up a free space loss model to predict > > what the signal level(s) should be? > It is too complex for me :-) And I'm not sure, that I have tool to > measure real signal to compare with calculations. > > -- > // Black Lion AKA Lev Serebryakov <lev@freebsd.org> > > _______________________________________________ > freebsd-wireless@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-wireless > To unsubscribe, send any mail to "freebsd-wireless-unsubscribe@freebsd.or= g > " > Hi maybe you device have interference with other devices in room. try to lowe= r .. turn off other devices if u have in room . what show ifconfig wlan0 scan ?? how much is noise level ?? i have AR5212 and it work great over 6m inside house (2 walls). transfer rate i get is 2.4~3.2MB/s Beri
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