Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id v94Ctd9L021428 for ; Wed, 4 Oct 2017 14:55:40 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dzj7G-0004I9-5h for rs_out_1@blacksheep.org; Wed, 04 Oct 2017 13:49:34 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dzj7F-0004I0-9w for rsgb_lf_group@blacksheep.org; Wed, 04 Oct 2017 13:49:33 +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 1dzj7C-0007Ny-Gh for rsgb_lf_group@blacksheep.org; Wed, 04 Oct 2017 13:49:32 +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=uC8gHpnJlvWYfdmoagV3py3TUwdosjdnXOe6RZviOmE=; b=UVavUAbFzpWd6FXBD67DiuUh5A gxNBpmTotiCUy7c2vakchVIX1XBZDfT8nnM/nCpdgp+BhAYPYWzd+JWsZulrVsz+856+2LrcyN5Wj RZvv0NSfmNEWbcs2LaDjDK4J6W4p59HE7DNRysTZ5trkEPb3OI1LQCJ9JwYN+UJ8esqY=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:44554 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 1dzj7B-00089X-KS for rsgb_lf_group@blacksheep.org; Wed, 04 Oct 2017 13:49:29 +0100 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id F295A400215 for ; Wed, 4 Oct 2017 12:49:28 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <15ec7c794b3-bff-66@webjas-vac136.srv.aolmail.net> <59D2BD65.4080909@posteo.de> <59D4B109.27652.1415B4FA@mike.dennison.ntlworld.com> From: Paul Nicholson Message-ID: <7737095b-edc9-8b5f-ebf5-2a6b2884d425@abelian.org> Date: Wed, 4 Oct 2017 12:49:28 +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: <59D4B109.27652.1415B4FA@mike.dennison.ntlworld.com> 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-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Stefan wrote: > And for some reason, the signal was much stronger last night > at SQ5BPF. Did you see it? What could be the reason? I think this is typical of short ranges. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: a6b6ffaf48fdddf1ed5c25dc4bf03ee1 Subject: Re: VLF: 300 mA on 6470 Hz Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=FROM_ENDS_IN_NUMS 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 Stefan wrote: > And for some reason, the signal was much stronger last night > at SQ5BPF. Did you see it? What could be the reason? I think this is typical of short ranges. When I model the propagation using ray tracing, it needs the first dozen or more rays (ground wave, 1-hop, 2-hop, 3-hop and so on) to produce something like a realistic diurnal. At some ranges, 2 or 3 rays have significant contribution for much of the time amd small shifts of relative phase of the rays can make large changes to amplitude. Maybe we are seeing that. It gets simpler at longer range: the contribution from higher-hop paths is much reduced. > i'm changing to: > Coding 8K19A OK. The table shows also that for longer messages - convolutional payload of 36 bits or more such as 4chars+CRC12 or 3chars+CRC18, it is always worth using a rate 1/16 code, ie 16K. 8K or 4K codes have symbols twice and four times the duration, so would only be better if symbol timing was a potential problem, eg with fast signaling at LF or MF. You can see also that longer constraint lengths are more successful with larger payloads. Eg no point in using more than K21 with payloads between 18 and 36 bits, and limit to K23 which payloads up to 72 bits. The convolutional payload is always 6 * number_of_chars + CRC size. -- Paul Nicholson --