Return-Path: Received: from mtain-ma10.r1000.mx.aol.com (mtain-ma10.r1000.mx.aol.com [172.29.96.18]) by air-mc05.mail.aol.com (v127_r1.1) with ESMTP id MAILINMC054-a96a4b839a8666; Tue, 23 Feb 2010 04:06:14 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-ma10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 530CB38000091; Tue, 23 Feb 2010 04:06:11 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Njqhf-0008Kg-0a for rs_out_1@blacksheep.org; Tue, 23 Feb 2010 09:05:15 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Njqhe-0008KX-Ll for rsgb_lf_group@blacksheep.org; Tue, 23 Feb 2010 09:05:14 +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 1Njqhc-0000vr-EB for rsgb_lf_group@blacksheep.org; Tue, 23 Feb 2010 09:05:14 +0000 Received: from paranoid.lipkowski.org (localhost [127.0.0.1]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id o1N95stk009777 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 23 Feb 2010 10:05:54 +0100 Received: from localhost (sq5bpf@localhost) by paranoid.lipkowski.org (8.13.7/8.13.6/Submit) with ESMTP id o1N95s5H009774 for ; Tue, 23 Feb 2010 10:05:54 +0100 X-Authentication-Warning: paranoid.lipkowski.org: sq5bpf owned process doing -bs Date: Tue, 23 Feb 2010 10:05:54 +0100 (CET) From: Jacek Lipkowski To: rsgb_lf_group@blacksheep.org In-Reply-To: <38A51B74B884D74083D7950AD0DD85E82A1B10@File-Server-HST.hst.e-technik.tu-darmstadt.de> Message-ID: References: <260427.39843.qm@web28105.mail.ukl.yahoo.com> <38A51B74B884D74083D7950AD0DD85E82A1B0C@File-Server-HST.hst.e-technik.tu-darmstadt.de> <38A51B74B884D74083D7950AD0DD85E82A1B10@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: VLF_8.79 kHz 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: 3039ac1d60124b839a8312ef X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Those looking at vlf transmission should look at cave radio electronics, tens of kHz are used for communication and several kHz for beaconing. The antenna limitations aremuch greater than for radioamateur use. Brian Pease has a nice site: http://radiolocation.tripod.com/ He uses a 4kHz beacon with a very small antenna to cover several hundred meters via rock. The DQ receiver design is also worth a look. VY 73 Jacek / SQ5BPF