Return-Path: X-Spam-DCC: paranoid 1169; 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=-0.8 required=5.0 tests=BAYES_00,FORGED_RCVD_HELO, RATWARE_GECKO_BUILD 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 t06C9mL2011130 for ; Tue, 6 Jan 2015 13:09:50 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Y8Sp4-0006fB-Eq for rs_out_1@blacksheep.org; Tue, 06 Jan 2015 12:01:18 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Y8Sp4-0006f2-6w for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2015 12:01:18 +0000 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.84) (envelope-from ) id 1Y8Sp1-0003WY-Tf for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2015 12:01:17 +0000 Received: from sb.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by parrot.netcom.co.uk (Postfix) with ESMTP id EDC513273FC for ; Tue, 6 Jan 2015 11:59:48 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id BDB9E28A0EB1 for ; Tue, 6 Jan 2015 12:01:13 +0000 (UTC) Message-ID: <54ABCE89.8010705@abelian.org> Date: Tue, 06 Jan 2015 12:01:13 +0000 From: Paul Nicholson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <54AB0110.3030709@abelian.org> <013401d02939$14569e40$3d03dac0$@comcast.net> <54ABA271.9060201@abelian.org> In-Reply-To: <54ABA271.9060201@abelian.org> X-Scan-Signature: 7aa9ad08848e488e22e0ff1d71f4ef1d Subject: Re: VLF: Transatlantic messages at 8822Hz Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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: 1822 I made a spectrogram from the reconstructed carrier (the BPSK modulation removed by undoing the phase reversals). http://abelian.org/vlf/tmp/150106a.png The bin bandwidth is set to the bandwidth of the information bits. I think this demonstrates quite dramatically the strength of the forward error correction coding. It is remarkable and quite fascinating that 150 bits of information can be obtained error-free from that feeble looking trace on the spectrogram. Without undoing the modulation, the signal is spread over a bandwidth of about 0.125Hz and is completely invisible. -- Paul Nicholson http://abelian.org/ --