Return-Path: X-Spam-DCC: paranoid 1233; 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=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,RATWARE_GECKO_BUILD,SPF_PASS 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 u3SDC66K000891 for ; Thu, 28 Apr 2016 15:12:06 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1avlef-0004Ol-SV for rs_out_1@blacksheep.org; Thu, 28 Apr 2016 14:06:53 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1avlef-0004Oc-FX for rsgb_lf_group@blacksheep.org; Thu, 28 Apr 2016 14:06:53 +0100 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1avled-0007gk-TD for rsgb_lf_group@blacksheep.org; Thu, 28 Apr 2016 14:06:52 +0100 Received: from pn.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by parrot.netcom.co.uk (Postfix) with ESMTP id 3F3323273E5 for ; Thu, 28 Apr 2016 14:05:41 +0100 (BST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id A6ED740048A for ; Thu, 28 Apr 2016 13:06:50 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <1545cc43544-7b51-40b@webprd-a09.mail.aol.com> From: Paul Nicholson Message-ID: <57220AEA.5000506@abelian.org> Date: Thu, 28 Apr 2016 13:06:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1545cc43544-7b51-40b@webprd-a09.mail.aol.com> X-Scan-Signature: c1f72e5acb1277e013f90c915ad7ad68 Subject: Re: VLF: EbNaut transmission on 8270.1 Hz again - 73 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 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7891 > I noticed that in ebnaut-rx v0.4d the output with > best rank seems to persist, rather than the one > with fewest symbol errors It actually keeps the decode with the best path metric. The other options (best rank, best BER) don't perform so well on average. The log file doesn't show the path metric though, I'll fix that for the next revision. With the Viterbi decoder using soft decisions with Euclidean distance metric, the path metric is equivalent to the cross-correlation of the signal and the message symbols. The decoder is effectively doing a 'deep search' which tests all possible messages, not just a short list. I can't convince my decoder to produce anything other than 'V3' on this one. Hamming distance between 73 and V3 is 180. The differences are pretty evenly spread through the messages. -- Paul Nicholson --