Return-Path: Received: (qmail 10320 invoked from network); 6 Oct 2002 13:46:02 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 6 Oct 2002 13:46:02 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 18870 invoked from network); 6 Oct 2002 13:46:09 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 6 Oct 2002 13:46:09 -0000 X-SQ: A X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 17yBj0-0006pk-00 for rsgb_lf_group-outgoing@blacksheep.org; Sun, 06 Oct 2002 14:45:38 +0100 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.10) id 17yBiz-0006pa-00 for rsgb_lf_group@blacksheep.org; Sun, 06 Oct 2002 14:45:38 +0100 Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 17yBiV-0007Rz-00 for rsgb_lf_group@blacksheep.org; Sun, 06 Oct 2002 14:45:07 +0100 Received: from [147.197.232.252] (helo=rsch-15.herts.ac.uk) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 17yBiK-0003Mr-00 for rsgb_lf_group@blacksheep.org; Sun, 06 Oct 2002 14:44:56 +0100 Message-ID: <5.1.0.14.0.20021006143430.00ade750@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Sun, 06 Oct 2002 14:44:51 +0100 To: rsgb_lf_group@blacksheep.org From: "James Moritz" In-reply-to: <000f01c26d14$5f185980$3a567ad5@jackie> References: MIME-Version: 1.0 X-MailScanner: No Virus detected Subject: Re: LF: 136 beacon Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Status: No, hits=-4.1 required=5.0tests=IN_REP_TO,DEAR_SOMEBODYversion=2.31 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Dear Steve, LF Group, At 09:42 06/10/2002 +0100, you wrote: >Yesterday evening and this morning I'm getting a keyed beacon at about >136kHz, just below the level wher my ears or the computer can decode it. Can >someone tell me what it is, or is it a phantom? > >Thanks, > >Steve As Mike says, this is something many of us can hear - looked at on a high resolution spectrogram it consists of a number of weak carriers on almost exactly 136.0kHz - these beat together to produce the "CW beacon" effect. My favorite explanation is that these are harmonics of telecomms clock signals on 8kHz, being radiated by phone wires, etc - there are different signal components present in different locations. So this could well be a form of fairly local QRM rather than a receiver problem or an intermod. I also hear something similar on 72kHz when Rugby is QRT. Cheers, Jim Moritz 73 de M0BMU