Return-Path: Received: from mtain-mc11.r1000.mx.aol.com (mtain-mc11.r1000.mx.aol.com [172.29.96.83]) by air-dc08.mail.aol.com (v129.4) with ESMTP id MAILINDC084-86a64d4b0408254; Thu, 03 Feb 2011 14:37:45 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mc11.r1000.mx.aol.com (Internet Inbound) with ESMTP id F27ED380000A2; Thu, 3 Feb 2011 14:37:42 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Pl4z5-0000oh-3g for rs_out_1@blacksheep.org; Thu, 03 Feb 2011 19:36:51 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Pl4z4-0000oY-Kk for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 19:36:50 +0000 Received: from 113-mo2-8.acn.waw.pl ([62.121.95.113] helo=paranoid.lipkowski.org) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Pl4z2-0000Px-D7 for rsgb_lf_group@blacksheep.org; Thu, 03 Feb 2011 19:36:50 +0000 Received: from paranoid.lipkowski.org (localhost [127.0.0.1]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id p13JaiTm005040 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 3 Feb 2011 20:36:44 +0100 Received: from localhost (sq5bpf@localhost) by paranoid.lipkowski.org (8.13.7/8.13.6/Submit) with ESMTP id p13JaiHo005037 for ; Thu, 3 Feb 2011 20:36:44 +0100 X-Authentication-Warning: paranoid.lipkowski.org: sq5bpf owned process doing -bs Date: Thu, 3 Feb 2011 20:36:43 +0100 (CET) From: Jacek Lipkowski To: rsgb_lf_group@blacksheep.org In-Reply-To: Message-ID: References: MIME-Version: 1.0 X-Spam-Score-sq5bpf: -2.601 () BAYES_00,SPF_HELO_PASS,SPF_PASS X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: Earth-mode or not earth-mode Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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: 3039ac1d60534d4b040602fc X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) trying to couple to large structures is an interesting experiment, both for receiving and transmitting (only by induction of course :). think about power lines, phone lines (but unfortunately nowadays most are very short, and the rest is done via fiber), natural gas pipelines, railways etc. this is an example rx experiment: http://www.youtube.com/watch?v=sWsdaSmWg7E , these structures are usually very well grounded at regular intervals, but still some vlf will slip through the ground system, so they can be also used for tx too. a few miliamps at 9kHz into a large structure is detectable from a few hundred meters. actually the "utilities-assisted earth mode" works not only on transmit. a loop antenna near a long conductor will pick up a stronger signal (and also more qrm, so this doesn't always raise S/N). this might not be ham radio (or not radio at all), but is very interesting nevertheless VY 73 Jacek / SQ5BPF