Return-Path: Received: (qmail 6788 invoked from network); 7 Mar 2003 12:08:24 -0000 Content-Transfer-Encoding: 8bit Received: from netmail02.services.quay.plus.net (212.159.14.221) by mailstore with SMTP; 7 Mar 2003 12:08:24 -0000 Received: (qmail 27279 invoked by uid 10001); 7 Mar 2003 12:08:23 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by netmail02.services.quay.plus.net with SMTP; 7 Mar 2003 12:08:23 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.12) id 18rGdv-0002K1-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 07 Mar 2003 12:08:03 +0000 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.12) id 18rGdp-0002Js-00 for rsgb_lf_group@blacksheep.org; Fri, 07 Mar 2003 12:07:57 +0000 Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 18rGdI-0002QB-00 for rsgb_lf_group@blacksheep.org; Fri, 07 Mar 2003 12:07:24 +0000 Received: from [147.197.232.252] (helo=rsch-15.herts.ac.uk) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 18rGdG-0000Ed-00 for rsgb_lf_group@blacksheep.org; Fri, 07 Mar 2003 12:07:22 +0000 Message-ID: <5.1.0.14.0.20030307112221.00afb4f0@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Fri, 07 Mar 2003 12:03:32 +0000 To: rsgb_lf_group@blacksheep.org From: "James Moritz" In-reply-to: MIME-Version: 1.0 X-MailScanner: No Virus detected Subject: Re: LF: Re: LF broadband QRN?/overnight conditions Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Status: No, hits=-3.3 required=5.0tests=IN_REP_TOversion=2.50 X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Dear John, LF Group, Saw very good signals from CT1DRP last night between 2100 - 2300, which could easily have been copied at QRSS3, and which were often weakly audible - I think this is the first time I have actually heard Brian's signals. I find almost any mains electrical appliance with any electronics in it is a potential source of severe interference at LF. Things in "standby" mode can often generate more noise than when they are operating, so the only way to be sure if something is a noise source is to pull the mains plug out. Even if I switch off the mains supply to the house completely, the noise level is not greatly reduced, presumably due to common-mode signals from some distance away propagating along the mains earth wire. Strangely, my previous QTH in North London was almost totally free of mains noise. Any antenna close to the house will pick up noise from the house wiring; quite severely at 5m distance, and still annoying at 10m. Since my TX antenna has to come right up to the house to use the available space effectively, it is always noisy on receive. This means I have to resort to separate receive antennas to get reasonable reception, which tend to cluster at the bottom of the garden. Even then, there seem to be relatively distant noise sources which can prove sporadically troublesome. Apart from a few trials, I think the wide-area PLT schemes are not yet "legal" due to their requirement to push high levels of signal into the mains cabling in order to overcome the high intrinsic noise levels. For this reason, If they do become generally used, they are bound to make the mains noise situation worse. Cheers, Jim Moritz 73 de M0BMU