Return-Path: Received: from rly-me03.mx.aol.com (rly-me03.mail.aol.com [172.20.83.36]) by air-me02.mail.aol.com (v126.13) with ESMTP id MAILINME022-9a64b27934be7; Tue, 15 Dec 2009 08:46:57 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-me03.mx.aol.com (v125.7) with ESMTP id MAILRELAYINME032-9a64b27934be7; Tue, 15 Dec 2009 08:46:53 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NKXhG-0004Xc-JB for rs_out_1@blacksheep.org; Tue, 15 Dec 2009 13:44:14 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NKXhG-0004XT-6l for rsgb_lf_group@blacksheep.org; Tue, 15 Dec 2009 13:44:14 +0000 Received: from smtp-vbr15.xs4all.nl ([194.109.24.35]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NKXiv-0003mQ-0M for rsgb_lf_group@blacksheep.org; Tue, 15 Dec 2009 13:45:59 +0000 Received: from webmail.xs4all.nl (dovemail12.xs4all.nl [194.109.26.14]) by smtp-vbr15.xs4all.nl (8.13.8/8.13.8) with ESMTP id nBFDjcmv067165 for ; Tue, 15 Dec 2009 14:45:51 +0100 (CET) (envelope-from roelof@ndb.demon.nl) Received: from 82.92.124.189 (SquirrelMail authenticated user pa0rdt) by webmail.xs4all.nl with HTTP; Tue, 15 Dec 2009 14:45:51 +0100 Message-ID: <7d0f030f6b6dc3a9cbc3df0e004002df.squirrel@webmail.xs4all.nl> In-Reply-To: References: <4B250D02.733.14E9A34@mike.dennison.ntlworld.com> <38A51B74B884D74083D7950AD0DD85E828AC66@File-Server-HST.hst.e-technik.tu-darmstadt.de> Date: Tue, 15 Dec 2009 14:45:51 +0100 From: "Roelof Bakker" To: rsgb_lf_group@blacksheep.org User-Agent: SquirrelMail/1.4.18 MIME-Version: 1.0 X-Virus-Scanned: by XS4ALL Virus Scanner X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: "Gain" between qrss3 and qrss10? Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit 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-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Dear Andy, Thank you very much for your educational piece on the signal to noise improvement possible for various modes. It might interest you that I have been testing the limits of aural CW copy using narrow analogue filters. It appears that after some exercise the human brain-ear system can adapt itself to a bandwidth of 5 Hz for slow speed morse code; e.g. the CW identifier of non directional beacons. This offers a 20 dB improvement compared to a standard 500 Hz CW bandwidth and seems to be as good as it gets. The irony is that these tests were triggered by the appearence of narrow DSP filters. Had I known this 40 year ago, it should have been an excellent opportunity to show the possibilities of very low power transmissions at HF! Best regards, Roelof bakker, pa0rdt