Return-Path: Received: from mtain-mh01.r1000.mx.aol.com (mtain-mh01.r1000.mx.aol.com [172.29.96.213]) by air-mf02.mail.aol.com (v129.4) with ESMTP id MAILINMF023-8bcf4bffb6612ad; Fri, 28 May 2010 08:26:09 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mh01.r1000.mx.aol.com (Internet Inbound) with ESMTP id A6E4438000089; Fri, 28 May 2010 08:26:07 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OHycX-0001p5-06 for rs_out_1@blacksheep.org; Fri, 28 May 2010 13:25:01 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OHycW-0001ou-7q for rsgb_lf_group@blacksheep.org; Fri, 28 May 2010 13:25:00 +0100 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 1OHycU-0003sM-0g for rsgb_lf_group@blacksheep.org; Fri, 28 May 2010 13:25:00 +0100 Received: from paranoid.lipkowski.org (localhost [127.0.0.1]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id o4SCOvjU025990 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 28 May 2010 14:24:57 +0200 Received: from localhost (sq5bpf@localhost) by paranoid.lipkowski.org (8.13.7/8.13.6/Submit) with ESMTP id o4SCOv37025987 for ; Fri, 28 May 2010 14:24:57 +0200 X-Authentication-Warning: paranoid.lipkowski.org: sq5bpf owned process doing -bs Date: Fri, 28 May 2010 14:24:57 +0200 (CEST) From: Jacek Lipkowski To: rsgb_lf_group@blacksheep.org In-Reply-To: Message-ID: References: <38A51B74B884D74083D7950AD0DD85E82A1C00@File-Server-HST.hst.e-technik.tu-darmstadt.de> 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: AW: 8.97kHz - Near field and radiated signals? 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: S x-aol-sid: 3039ac1d60d54bffb65f44a0 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) On Wed, 26 May 2010, Roger Lapthorn wrote: > - What antenna did you use for RX? Loop, e-field probe? i used an e-field probe > - Have you tried TXing using grounded electrodes? If so, what range did > you achieve and what RX antenna did you use? i've tried to couple to various structures (underground wires etc), one of them worked like a ground dipole. i got around 750m with 1.8W: http://acid.ch.pw.edu.pl/~sq5bpf/ham/vlf/20100203/vlfcapt3747.jpg this was in february, during summer the distance would have been smaller. this is from a bit shorter distance, around 570m: http://acid.ch.pw.edu.pl/~sq5bpf/ham/vlf/20100203/vlfcapt3744.jpg i have tried using 40W into a 1.5x2.5m 3 turn loop - in this case there was marginal copy at the same location (can't find the spectrogram unfortunately). as you can see in this case it's much better than marginal. i've used a loop for both tests. i've tried the location 1.3km away (that was not a problem for e-field antennas), but didin't receive anything. actually i would be surprised to receive something at 1.3km, it it was marginal with half of this distance. so you can see that at least in my case the e-fields antenna clearly wins btw performing these tests in the city is not just a matter of turning on the tx and driving around. you have to search for quiet sites to listen, and drive there. jacek