Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dc06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 13375380000B1; Sat, 12 May 2012 07:05:58 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1STA8T-0007EL-Kt for rs_out_1@blacksheep.org; Sat, 12 May 2012 12:05:17 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1STA8T-0007EC-8y for rsgb_lf_group@blacksheep.org; Sat, 12 May 2012 12:05:17 +0100 Received: from smtp-vbr10.xs4all.nl ([194.109.24.30]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1STA8R-0002oY-1J for rsgb_lf_group@blacksheep.org; Sat, 12 May 2012 12:05:16 +0100 Received: from pc-roelof (ndb.demon.nl [82.161.81.65]) by smtp-vbr10.xs4all.nl (8.13.8/8.13.8) with ESMTP id q4CB58gG038609 for ; Sat, 12 May 2012 13:05:14 +0200 (CEST) (envelope-from roelof@ndb.demon.nl) To: rsgb_lf_group@blacksheep.org References: Date: Sat, 12 May 2012 13:04:59 +0200 MIME-Version: 1.0 From: "Roelof Bakker" Message-ID: In-Reply-To: User-Agent: Opera Mail/11.64 (Win32) X-Virus-Scanned: by XS4ALL Virus Scanner X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Andy, Thank you for this little gem. I have been playing with it for a while. With a signal to noise ratio of -10 dB in 2500 Hz, I can copy a 10 WPM message with the output filter set to 2500 Hz. Estimating my brain ear system bandwidth as 50 Hz, the effective signal to noise ratio is 6.9 dB. This seems a bit on the low side, so the biological filter seems to be even narrower than 50 Hz. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [194.109.24.30 listed in list.dnswl.org] X-Scan-Signature: 1f795a2ee1ecd56682b47ad11969b3d3 Content-Type: text/plain; charset=iso-8859-15; format=flowed; delsp=yes Subject: Re: LF: Demonstrating audibility of weak signals - utilty to play with. Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:434290176:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d40864fae44160825 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hello Andy, Thank you for this little gem. I have been playing with it for a while. With a signal to noise ratio of -10 dB in 2500 Hz, I can copy a 10 WPM message with the output filter set to 2500 Hz. Estimating my brain ear system bandwidth as 50 Hz, the effective signal to noise ratio is 6.9 dB. This seems a bit on the low side, so the biological filter seems to be even narrower than 50 Hz. Setting the output filter to 20 Hz, results in armchair copy. The CW tone in this case is 300 Hz. 73, Roelof, pa0rdt