Date: Thu, 27 May 2010 09:58:05 +0200 From: Miroslav Chlastak <mira@chlastak.cz> To: Rui Paulo <rpaulo@FreeBSD.org> Cc: freebsd-mobile@freebsd.org Subject: Re: Atheros and how to convert RSSI to dBm Message-ID: <4BFE260D.1090701@chlastak.cz> In-Reply-To: <BFBFCF99-8D2E-43BB-98DA-2B681C99514D@FreeBSD.org> References: <4BFD9FE4.3090309@chlastak.cz> <BFBFCF99-8D2E-43BB-98DA-2B681C99514D@FreeBSD.org>
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On 27.5.2010 02:16, Rui Paulo wrote: > On 26 May 2010, at 23:25, Miroslav Chlastak wrote: > > >> Hello, >> >> is there a way how to convert RSSI from output of "ifconfig ath0 list sta" to dBm?: >> >> [snip] >> >> ADDR AID CHAN RATE RSSI IDLE TXSEQ RXSEQ CAPS FLAG >> 00:4f:62:1d:d8:5d 14 9 11M 18.5 0 15932 22400 ES A >> >> [snip] >> >> I my test enviroment I use this function: >> noise floor + RSSI*2 = signal of client in dBm >> >> Then i get the same value as from "tcpdump -n -i ath0 -p -y IEEE802_11_RADIO": >> >> [snip] >> >> 10:41:04.746395 86402611933us tsft short preamble 58.5 Mb/s -61dB signal -98dB noise antenna 1 [0x00000012] IP 10.0.0.1.2049> 192.168.100.2.123: NTPv3, Client, length 48 >> >> [snip] >> >> >> Right? Or is this conversion "stupid"? Some better idea? >> >> Is there a way how to get noise floor via "ifconfig"? I get it from output of "athstats" :( >> > No, there's no way right now. > > Check this: http://lists.freebsd.org/pipermail/freebsd-stable/2006-September/028895.html > > Regards, > -- > Rui Paulo > > > But this mail was sent on September 2006 - it's still impossible? :( And how to do it tcpdump? tcpdump -n -i ath0 -p -y IEEE802_11_RADIO": [snip] 10:41:04.746395 86402611933us tsft short preamble 58.5 Mb/s -61dB signal -98dB noise antenna 1 [0x00000012] IP 10.0.0.1.2049> 192.168.100.2.123: NTPv3, Client, length 48 [snip] Signal -61dB is right signal of my connected wireless client. Tcpdump this signal "know", but system (via ifconfig) doesn't? -- Mira Chlastak
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