Return-Path: Received: from mtain-dl06.r1000.mx.aol.com (mtain-dl06.r1000.mx.aol.com [172.29.74.212]) by air-me01.mail.aol.com (v129.10) with ESMTP id MAILINME011-8ba04de79cefc9; Thu, 02 Jun 2011 10:23:43 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 1D63038000119; Thu, 2 Jun 2011 10:23:40 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QS8nN-0005yA-6B for rs_out_1@blacksheep.org; Thu, 02 Jun 2011 15:22:45 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QS8nM-0005y1-Ea for rsgb_lf_group@blacksheep.org; Thu, 02 Jun 2011 15:22:44 +0100 Received: from mail.foreach.it ([213.254.15.250] helo=for01.foreach.it) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QS8nK-0003wB-MS for rsgb_lf_group@blacksheep.org; Thu, 02 Jun 2011 15:22:44 +0100 Received: by for01.foreach.it (Postfix, from userid 65534) id 4ABFE2801BF; Thu, 2 Jun 2011 16:29:39 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by for01.foreach.it (Postfix) with ESMTP id DFF772801B9 for ; Thu, 2 Jun 2011 16:29:38 +0200 (CEST) X-Virus-Scanned: amavisd-new at ebirds.it Received: from for01.foreach.it ([127.0.0.1]) by localhost (for01.foreach.it [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fHUkS3BSTa02 for ; Thu, 2 Jun 2011 16:29:38 +0200 (CEST) Received: from imac2 (host185-41-static.24-87-b.business.telecomitalia.it [87.24.41.185]) by for01.foreach.it (Postfix) with ESMTP id 9D3B428014F for ; Thu, 2 Jun 2011 16:29:38 +0200 (CEST) X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Thu, 02 Jun 2011 16:22:39 +0200 To: rsgb_lf_group@blacksheep.org From: Marco IK1ODO -2 In-Reply-To: <4DE79742.1000509@telus.net> References: <4DE77311.8010604@talktalk.net> <4DE79742.1000509@telus.net> Mime-Version: 1.0 Message-Id: <20110602142938.DFF772801B9@for01.foreach.it> X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Schumann Content-Type: text/plain; charset="us-ascii"; format=flowed X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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 x-aol-global-disposition: G x-aol-sid: 3039ac1d4ad44de79ceb5b88 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none The first Schumann resonance is not at (300000/40000)=7.5 Hz, but higher, usually around 7.7-7.8 Hz. I was astounded when I observed it for the first time about 12 years ago and found that the frequency was "not right" !:-) The reason is simple: our Earth is quite transparent at very low frequencies, so the average circumference of the ionosphere-Earth waveguide is shorter than 40000 km. In other words, the center of the first Schumann resonance is below your feet, at a deptht of approximately 300 km. The second one is a little bit higher than 15 Hz, and progressively the other come closer to harmonics of a 40000 km wavelenght; but since the Q is low, it is dfficult to extimate the exact frequency. Have a look at http://www.vlf.it/Schumann/schumann.htm. Years ago there was a website from Stanford University reporting the measured frequency of Schumann resonances vs. time. The frequency changes because of day/night ionospheric height variations, and beacuse of SIDs and other disturbances. Fascinating ! To receive them you need a very large coil, or a simple E field receiver and a quiet location; feed the signal to an audio interface, and run a spectrogram in average mode. Quite easy to say, but it takes some ingenuity and work to extract an useable signal. Renato IK1QFK has a live spectrogram covering from 0.1 Hz up, see http://www.vlf.it/cumiana/livedata.html - today we have thunderstorms in the area, and the signal is completely wiped out. Vy 73 - Marco IK1ODO