Return-Path: Received: (qmail 17956 invoked from network); 16 Aug 1999 23:00:43 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 16 Aug 1999 23:00:43 +0100 Received: (qmail 4205 invoked from network); 16 Aug 1999 16:16:08 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 16 Aug 1999 16:16:08 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11GP4T-0006pW-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 16 Aug 1999 16:53:13 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from nms.rz.uni-kiel.de ([134.245.1.2]) by post.thorcom.com with smtp (Exim 3.02 #1) id 11GP4S-0006pR-00 for rsgb_lf_group@blacksheep.org; Mon, 16 Aug 1999 16:53:12 +0100 Received: from srv1.mail.uni-kiel.de by nms.rz.uni-kiel.de with Local-SMTP (PP); Mon, 16 Aug 1999 17:52:39 +0200 Received: from nephro.uni-kiel.de (PC10847.dial.uni-kiel.de [134.245.108.47]) by srv1.mail.uni-kiel.de (8.9.1b+Sun/8.9.1) with ESMTP id RAA03292 for ; Mon, 16 Aug 1999 17:52:57 +0200 (MET DST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: <37B833BF.15126C1C@nephro.uni-kiel.de> Date: Mon, 16 Aug 1999 17:52:31 +0200 From: "Peter W. Schnoor" Organization: University of Kiel, Clinic of Nephrology X-Mailer: Mozilla 4.05 [en] (X11; I; Linux 2.0.33 i586) To: rsgb_lf_group@blacksheep.org Subject: LF: Solar Flare on LF... MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: Hello Group, Recording HBG75 (75 kHz) over the whole last week I found a strong anomaly at Saturday, 14th. I observed a steep increase of field strength (9dB) followed by a smooth decrease looking like a typical exponential function. Looking to sites offering geomagnetic data I could not explain it. So my first assumption was that it could have been an artefact. Expanding the graph to higher zoom level showed the typical weak 60sec. rhythm of HBG due to my short integration time in front of the A/D-Convertor (time constant 2.6sec.). So I'm sure that it was the signal of HBG and not any kind of noise source. J.J.Delcourt from RMI gave the explanation: It was the influence of a Solar Flare on LF propagation. (Thank you!) I never observed this before... A plot of this event can be found there: ftp://ftp.rz.uni-kiel.de/pub/nephro/nephlab/lp/solarflare.gif 54°16'N / 10°04'E, JO54ag 73 es gl de Peter, DF3LP