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 t06JZ1GD012236 for ; Tue, 6 Jan 2015 20:35:01 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Y8ZnN-0007XL-Ul for rs_out_1@blacksheep.org; Tue, 06 Jan 2015 19:28:01 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Y8ZnN-0007XC-JB for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2015 19:28:01 +0000 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.84) (envelope-from ) id 1Y8ZnL-0007aA-St for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2015 19:28:00 +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 717353273D6 for ; Tue, 6 Jan 2015 19:26:32 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id CB5CD28A1374 for ; Tue, 6 Jan 2015 19:27:57 +0000 (UTC) Message-ID: <54AC373D.4020108@abelian.org> Date: Tue, 06 Jan 2015 19:27:57 +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: <76C79F82BC6247E282D17D73B8444AF9@White> In-Reply-To: <76C79F82BC6247E282D17D73B8444AF9@White> X-Scan-Signature: ac0f6ff1af52b6036ac1f4fe0c2bd52c Subject: Re: VLF: 8270 carrier 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: 1827 DF6NM 10uW ERP at 8270 Hz at Todmorden, 1028 km. S/N and phase (lead) in 278 uHz (1 hour) averages Start ---H-field---- ---E-field---- 00:30 6.8 dB -51.2 -0.7 dB 01:00 4.7 dB -50.5 -7.3 dB 01:30 8.5 dB -49.0 12.9 dB -61.0 02:00 10.6 dB -65.4 13.5 dB -63.3 02:30 11.5 dB -82.1 11.5 dB -67.8 03:00 11.5 dB -94.9 10.4 dB -84.6 03:30 10.6 dB -112.9 11.9 dB -77.9 04:00 11.1 dB -119.6 14.0 dB -79.1 04:30 12.3 dB -108.7 13.6 dB -98.3 05:00 12.3 dB -103.8 10.1 dB -94.5 05:30 13.8 dB -108.1 12.9 dB -101.8 06:00 12.5 dB -97.8 14.9 dB -103.1 06:30 10.4 dB -80.6 11.8 dB -91.5 07:00 10.6 dB -92.0 11.1 dB -83.2 07:30 11.0 dB -96.6 10.8 dB -87.8 08:00 10.9 dB -84.8 8.5 dB -78.2 08:30 12.6 dB -73.6 9.1 dB -79.2 09:00 14.1 dB -74.7 10.8 dB -89.8 Phase is steady enough from 02:00 to 10:00. 02:00 to 10:00 averages: Flux density 0.09 fT In 34.7 uHz: H field 20.4 dB, E field 20.8 dB In 278 uHz: H field 10.9 dB, E field 11.0 dB In 278 uHz: E+H combined: 14.3 dB Considering just the H-field and allowing 0.5 dB margin, that's just enough for 17 characters, 12.5 second symbols, rate 1/16 K=25. Eb/N0 would be about -0.6 dB, and 81% of capacity. I tend not to factor in the E-field rx for these estimates, it is more susceptible to weather and some nights can be useless for weak signals. It is useful to keep in reserve. But last night the E-field was very good. Using it, we could try a less strong code, rate 1/8 K=21. This has about 0.5 dB or so less coding gain but is capable of being decoded on a domestic PC. Rate 1/8 K=21 symbol period 16 seconds, 31 character message, Eb/N0 around -0.2 dB, for 77% of capacity. -- Paul Nicholson http://abelian.org --