Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v467dnAW021745 for ; Sat, 6 May 2017 09:39:50 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1d6uBT-0002Vq-SJ for rs_out_1@blacksheep.org; Sat, 06 May 2017 08:31:19 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1d6uAe-0002Vg-4l for rsgb_lf_group@blacksheep.org; Sat, 06 May 2017 08:30:28 +0100 Received: from porthos.netcom.co.uk ([217.72.171.73]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1d6uAZ-0002rw-Oi for rsgb_lf_group@blacksheep.org; Sat, 06 May 2017 08:30:25 +0100 X-DKIM-Result: Domain=abelian.org Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=abelian.org ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:To:Subject:Sender:Reply-To:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=GExO3S97ezi97rzY2MDZ8krUXDihfOv1UHHdaj25tXs=; b=Qhwb8W0LSpSW+59amoVk6afXkQ JvqlPhwzCZ6VsohPFJhVa3yk0osUyuifvUc3VcjzvL+YdTnLZ8eSvOQUT2PeqsX5Wg3d8KI7IL9iB dwg6slsVL1WjFfkh0MlC+fUVOD1vhdPoLWJV21rMWRP+FE6dPibRQINhZnPxyUeUk9dI=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:57294 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1d6uAY-0005In-VO for rsgb_lf_group@blacksheep.org; Sat, 06 May 2017 08:30:23 +0100 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 4C446400052 for ; Sat, 6 May 2017 07:30:22 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <15bd53dda31-14f8-1cb1c@webprd-m59.mail.aol.com> <590B9892.9010406@posteo.de> <1493995971.279577405@f347.i.mail.ru> <590CA917.70808@posteo.de> <590CEE68.4000507@posteo.de> From: Paul Nicholson Message-ID: <06325bab-8730-3304-f28b-89bf98f6c680@abelian.org> Date: Sat, 6 May 2017 07:30:22 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <590CEE68.4000507@posteo.de> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - porthos.netcom.co.uk X-AntiAbuse: Original Domain - blacksheep.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - abelian.org X-Get-Message-Sender-Via: porthos.netcom.co.uk: authenticated_id: catchall@abelian.org X-Authenticated-Sender: porthos.netcom.co.uk: catchall@abelian.org X-Scan-Signature: 046f068074e745d5c60ca47deee9b503 Subject: Re: VLF: tonite on the 36km band... Content-Type: text/plain; charset=utf-8; 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 2.75 Status: RO X-Status: X-Keywords: X-UID: 11602 Stefan wrote: > f = 8270.100000 Hz > Start time: 05.May.2017 05:30:00 UTC > Symbol period: 10 s > Characters: 100 > CRC bits: 0 > Coding 8K19A Decoded after a bit of work "THIS IS A NEW LONGEST EBNAUT MESSAGE ON VLF. 881 KM ON THE 36 KM BAND. JOIN THE VLF ACTIVITIES! 73!" list rank: 0 constant reference phase carrier phase: 113.5 carrier Eb/N0: 0.2 dB carrier S/N: 27.81 dB in 20.2 uHz, -19.14 dB in 1Hz, -53.11 dB in 2.5kHz I started with daytime settings for sferic blanking and got a close but false decode. Reducing the blanker threshold almost to night setting produced the correct decode. I'm noticing that the probability of false decodes with long messages is much higher than I expected. It is something to do with the message being many times the constraint length of the convolutional code. This I will have to study to understand properly. There are 30 bits of redundancy for the outer code to use but we don't seem to get the full benefit of it. Some trials with 200 character messages are showing this clearly. -- Paul Nicholson --