Return-Path: Received: from mtain-dd02.r1000.mx.aol.com (mtain-dd02.r1000.mx.aol.com [172.29.64.142]) by air-db09.mail.aol.com (v129.4) with ESMTP id MAILINDB091-85f54d9df0381ba; Thu, 07 Apr 2011 13:11:20 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd02.r1000.mx.aol.com (Internet Inbound) with ESMTP id C1B44380000B9; Thu, 7 Apr 2011 13:11:18 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Q7siC-0004m0-I3 for rs_out_1@blacksheep.org; Thu, 07 Apr 2011 18:09:40 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Q7siC-0004lr-43 for rsgb_lf_group@blacksheep.org; Thu, 07 Apr 2011 18:09:40 +0100 Received: from out1.ip09ir2.opaltelecom.net ([62.24.128.245]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Q7siA-0004OI-H7 for rsgb_lf_group@blacksheep.org; Thu, 07 Apr 2011 18:09:40 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArkCANTunU1OlmQL/2dsb2JhbAAMmGnPDoVtBJFI X-IronPort-AV: E=Sophos;i="4.63,317,1299456000"; d="scan'208";a="474222032" Received: from unknown (HELO [192.168.2.5]) ([78.150.100.11]) by out1.ip09ir2.opaltelecom.net with ESMTP; 07 Apr 2011 18:09:33 +0100 Message-ID: <4D9DEFC6.6030901@talktalk.net> Date: Thu, 07 Apr 2011 18:09:26 +0100 From: "qrss@talktalk.net" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4D9DE551.9020508@talktalk.net> In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: VLF QRM puzzle - why not the same in a split screen on SL? Content-Type: text/plain; charset=ISO-8859-1; 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=0.0 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: 3039ac1d408e4d9df036195d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) Hi Chris Coincidentally, yesterday I watched the peaks of dirty sine waves climbing up in frequency and for the first time I have observed them reaching above 8.971kHz, causing problems for me recieving Ossi on8.9697kHz. The peaks need no filter to knock them out, they go no farther (turn round and come back down again:-) ) so producing 2 vertical lines for each sine wave peak if you look below nothing above. 73 Eddie G3ZJO On 07/04/2011 17:45, Chris Trayner wrote: > On 7 Apr 2011, at 17:24, qrss wrote: >> Considering they >> originate from a 50Hz source they are strongest at lower frequencies, >> rarely climbing above 6kHz but peaks sometimes get to 8.971kHz not much >> higher.. > Yes, but they disappear between 8970.03 Hz and 9876.57 Hz - that's a very small band for anything to knock them out. It's 0.00105 of an octave. If something is acting like a low-pass filter, at 6dB/octave/order, it'd have to be something like a 500th order filter to drop the signal by 3dB. > > I agree, it does look strange. > > > 73, > Chris G4OKW > > ----------------------- > Dr Chris Trayner > School of Electronic& Electrical Engineering, > The University of Leeds, > Leeds LS2 9JT, United Kingdom > Tel: +44 113 34 32053 > Fax: +44 113 34 32032 > > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1209 / Virus Database: 1500/3556 - Release Date: 04/06/11 > > >