Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,HTML_TITLE_EMPTY,NO_REAL_NAME autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t8PAdhlA028577 for ; Fri, 25 Sep 2015 12:39:43 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZfQN9-000446-DQ for rs_out_1@blacksheep.org; Fri, 25 Sep 2015 11:36:59 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZfQN9-00043x-5O for rsgb_lf_group@blacksheep.org; Fri, 25 Sep 2015 11:36:59 +0100 Received: from lb3-smtp-cloud2.xs4all.net ([194.109.24.29]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.86) (envelope-from ) id 1ZfQME-0006o0-2M for rsgb_lf_group@blacksheep.org; Fri, 25 Sep 2015 11:36:58 +0100 Received: from [192.168.178.20] ([83.162.220.82]) by smtp-cloud2.xs4all.net with ESMTP id MNbk1r00R1nG4D701NblY3; Fri, 25 Sep 2015 12:35:45 +0200 From: roelof@ndb.demon.nl To: Andy Talbot , rsgb_lf_group@blacksheep.org Date: Fri, 25 Sep 2015 12:35:44 +0200 MIME-Version: 1.0 Message-ID: <56052380.4233.2F0953@roelof.ndb.demon.nl> In-reply-to: References: <0MNdxu-1Zl3vu0oLy-007AvH@mail.gmx.com>, , X-mailer: Pegasus Mail for Windows (4.70) X-Scan-Signature: 3f8d74a8c70dd416d0a3a1dbcb9bb89f Subject: Re: LF: First MF TA since a longer time Content-type: Multipart/Alternative; boundary="Alt-Boundary-31557.3082579" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4140 --Alt-Boundary-31557.3082579 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body Hello Andy, >>> You'll see that down to about -14dB S/n (2.5kHz) is just about detectable as an audio tone - although I doubt many even experienced OPs could read CW that low <<< Using a 10 Hz bandwidth the S/n is 24 dB in regard to an SSB bandwidth of 2500 Hz. For keying speeds of about 10 wpm, this is an easy copy. Using coherent detection a further inprovement is no problem at all. 73, Roelof Bakker, pa0rdt --Alt-Boundary-31557.3082579 Content-type: text/html; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body
Hello Andy,

>>> You'll see that down to about -14dB S/n (2.5kHz) is just about detectable as an audio tone - although I doubt many even experienced OPs could read CW that low <<<

Using a 10 Hz bandwidth the S/n is 24 dB in regard to an SSB bandwidth of 2500 Hz. For keying speeds of about 10 wpm, this is an easy copy.
Using coherent detection a further inprovement is no problem at all.

73,
Roelof Bakker, pa0rdt
  
--Alt-Boundary-31557.3082579--