From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:54229 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756294Ab1FCVfK (ORCPT ); Fri, 3 Jun 2011 17:35:10 -0400 Received: by bwz15 with SMTP id 15so2081894bwz.19 for ; Fri, 03 Jun 2011 14:35:09 -0700 (PDT) From: Christian Lamparter To: mmendez@srtrl.com Subject: Re: carl9170 noise floor calculation Date: Fri, 3 Jun 2011 23:35:06 +0200 Cc: linux-wireless@vger.kernel.org References: <1307047613.15440.8.camel@localhost.localdomain> In-Reply-To: <1307047613.15440.8.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Message-Id: <201106032335.07352.chunkeey@googlemail.com> (sfid-20110603_233515_154493_94543DF7) Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thursday 02 June 2011 22:46:53 Manuel Mendez wrote: > We are developing a product that uses a board similar to the DLink > DWA-160. Uh, there are at least two DWA-160 AR9170 revision and mysteriously users have reported strange problems with both?! So, my question: why not base your product on ath9k_htc instead? > We are sticking an amplifier before the usb radios. I am pumping > beacons at say -80dBm from a siggen and a program reading the > radiotap header prints them out. > > I am seeing ~20dBm gain which looks right, when taking into account my > PA and the one that looks to be on the actual USB cards. > > Is there a way to use the pre-gain values for noise floor calculations, > and reporting of signal strength? probably not, in fact the whole noise floor and signal strength calculations are not as straight forward as you might think?! http://www.mail-archive.com/ath9k-devel@lists.ath9k.org/msg05777.html http://www.spinics.net/lists/linux-wireless/msg50060.html [there's more, just ask google about ath9k and noise] Also, since you are adding an extra amplifier: Are you thinking about long-range links? Because you'll need to tinker with the round trip time MAC registers then. Regards, Chr