Return-Path: Received: (qmail 20689 invoked from network); 9 Jan 2003 11:16:20 -0000 Received: from netmail02.services.quay.plus.net (212.159.14.221) by mailstore with SMTP; 9 Jan 2003 11:16:20 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 11411 invoked from network); 9 Jan 2003 10:16:11 -0000 Received: from post.thorcom.com (193.82.116.70) by netmail02.services.quay.plus.net with SMTP; 9 Jan 2003 10:16:10 -0000 X-Priority: 3 X-MSMail-Priority: Normal X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.12) id 18WZih-0004Xj-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 09 Jan 2003 10:15:27 +0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from [134.58.241.13] (helo=mail3.cc.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.12) id 18WZig-0004XQ-00 for rsgb_lf_group@blacksheep.org; Thu, 09 Jan 2003 10:15:26 +0000 Received: from dell-rik.fys.kuleuven.ac.be (ssl31-dmz.kuleuven.net [134.58.241.96]) by mail3.cc.kuleuven.ac.be (8.12.1/8.12.1) with ESMTP id h09AEumP068382 for ; Thu, 9 Jan 2003 11:14:56 +0100 Message-ID: <5.1.0.14.0.20030109111020.02cabf50@pb623250.kuleuven.be> X-Sender: pb623250@pb623250.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Thu, 09 Jan 2003 11:22:17 +0100 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: <5.1.0.14.2.20030109085759.00a04cd0@mail.pncl.co.uk> MIME-Version: 1.0 Subject: Re: LF: Noise Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Status: No, hits=-0.3 required=6.0tests=IN_REP_TO,SPAM_PHRASE_01_02version=2.43 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 >Apart from that, can anyone tell me why local noise IS a >vertically-polarised E-field problem? I can intuitively (I think) >understand that it would be E-field since it is primarily a high-impedance >phenomenon; but why VERTICALLY-polarised? If it's radiated from local >house wiring etc surely it should be randomly-polarised and just as >evident on horizontally-polarised antennas? I have a 30 m vertical I >occasionally use on 80m and a horizontal dipole for 80m near it. VERY >often there is so much noise on the vertical I can't even hear my local >net; on the horizontal at the same time there is only the faintest trace >of noise and everyone is easily audible. Same on 160m. All the texbooks >agree local noise is vertically-polarised but not one of them explains why. Hello Walter, Maybe "local noise" is vertically polarized because it is generated "against ground" : the wiring in the house acts as antenna, the ground as counterweight. As far as I got it any "against ground" fed antenna is vertically polarized, a nice example is the DDRR antenna that is a completely horizontal construction and yet a vertical polarized antenna. But there might be another reason for the high noise levels on your vertical : Years ago I contructed a full-sized Marconi antenna for 7MHz. In an attempt to be smart I connected just a few short radials and used the "house grounding stake" as counterweight. That worked fine on TX (antenna resistance was very close to 36 Ohm) but I had a tremendous noiselevel on RX. Disconnecting the "house grounding stake" solved the noise problem, but I had to add more and longer radials to get the antenna impedance back to 36 Ohm. 73, Rik ON7YD