Return-Path: Received: from mtain-db03.r1000.mx.aol.com (mtain-db03.r1000.mx.aol.com [172.29.64.87]) by air-mb08.mail.aol.com (v127_r1.1) with ESMTP id MAILINMB084-a8064b879854204; Fri, 26 Feb 2010 04:45:56 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-db03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 412BE38000092; Fri, 26 Feb 2010 04:45:55 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Nkwk4-0003fZ-EV for rs_out_1@blacksheep.org; Fri, 26 Feb 2010 09:44:16 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Nkwk3-0003fQ-WA for rsgb_lf_group@blacksheep.org; Fri, 26 Feb 2010 09:44:15 +0000 Received: from pne-smtpout1-sn1.fre.skanova.net ([81.228.11.98]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Nkwk1-0003Zu-AQ for rsgb_lf_group@blacksheep.org; Fri, 26 Feb 2010 09:44:15 +0000 Received: from [127.0.0.1] (81.235.167.68) by pne-smtpout1-sn1.fre.skanova.net (7.3.140.3) (authenticated as u33233109) id 4B5C64F70046D030 for rsgb_lf_group@blacksheep.org; Fri, 26 Feb 2010 10:44:06 +0100 Message-ID: <4B8797E9.9060500@telia.com> Date: Fri, 26 Feb 2010 10:44:09 +0100 From: "Johan H. Bodin" User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <38A51B74B884D74083D7950AD0DD85E82A1B18@File-Server-HST.hst.e-technik.tu-darmstadt.de> <70718ADC6A924E2F9BA6C5F1294DAD14@JimPC> <931424D0B09442018D818E6AD1E5A63A@White> In-Reply-To: <931424D0B09442018D818E6AD1E5A63A@White> X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Re: 9kHz noise level Content-Type: text/plain; charset=ISO-8859-1 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=0.0 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: 3039ac1d40574b8798531b26 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Jay, Marcus, LF, jrusgrove@comcast.net wrote: ... > There appeared to be a noticeable quiet spot in the > waterfall between ~ 8 and 9 kHz. I didn't investigate > if this was an anomoly in the system or if there happens > to be a quiet spot at that frequency. When sferics are weak or absent, I often see a "dark band" in that region, even with a nonresonant antenna (for example an E-field probe which is "flat"). Markus Vester wrote: ... > Part of the discrepancy > could be that published figures inevitably include the energy of the > distict spherics, which may well contribute the dominant part of the > average noise power. Yes, and that is probably why ITU's published figures show such a huge difference between summer and winter. The radio spectrum emitted by lightning discharges has a broad "hump" around 10kHz so it is a good idea to hurry up with the experiments now before the northern hemisphere moves into the QRN season. ;-) 73 Johan SM6LKM