Date: Wed, 25 May 2011 00:43:21 +0800 From: Adrian Chadd <adrian@freebsd.org> To: Shant Kassardjian <shant@skylab.ca> Cc: freebsd-wireless@freebsd.org Subject: Re: SR71-A Txpower Question Message-ID: <BANLkTi=V6c5b_9Y4QMvGSRO12WpUt0g70Q@mail.gmail.com> In-Reply-To: <SNT128-W29A6964FF2FE4EF51F555EDC750@phx.gbl> References: <SNT128-W29A6964FF2FE4EF51F555EDC750@phx.gbl>
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Hi, ifconfig wlan0 txpower 0 merely sets the txpower to 0dBm, which isn't "off" strictly speaking. It's actually 1mW. The SR-71A also has a TX power offset in hardware. If I remember right, the hardware is actually a couple of dBm higher than what you configure. So when you configure 19 dBm, you're programming the hardware at 19dBm, but the hardware responds by allowing a max of 16dBm per channel, which is * 3 (3 TX chains, as per the patch I gave you) to give ~ 21dBm. I'd have to check the math to get the exact tx power offset but that's roughly what's going on. Now, if it's documented somewhere that 0 dBm should be "killing" the interface, let me know. :) Adrian On 25 May 2011 00:24, Shant Kassardjian <shant@skylab.ca> wrote: > > Hello FreeBSD-Wireless, > > I've been running SR71-A on FreeBSD 8.1 for quite some time now and it's been running very well. Many thanks to Adrian Chadd who really helped ironing out all my questions! > > My only problem so far that I've noticed is that when I do: ifconfig wlan0 txpower 0; this does not turn off power to the wireless as it's suppose to and rather I have to bring down the interface manually to shut it down hence whenever I need to start it up again I have to reconfigure the interface. > > >From my observation it looks like changing the txpower rate using ifconfig has little to no effect controlling this adapter. > > > My question is that, could it be because I have compiled the kernel with the following modifications as suggested by Adrian Chadd to take advantage of Max 3x antenna transmit power that I am having this problem? > > Edit sys/dev/ath/ath_hal/ar5416/ar5416.h: > > #define AR5416_DEFAULT_RXCHAINMASK 7 > #define AR5416_DEFAULT_TXCHAINMASK 7 > > > Does anyone else have this symptom with their SR71-A (AR5416)? > > > Many thanks in advance; > > Regards, > Shant K. > _______________________________________________ > freebsd-wireless@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-wireless > To unsubscribe, send any mail to "freebsd-wireless-unsubscribe@freebsd.org" >
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