Return-Path: Received: from mtain-me11.r1000.mx.aol.com (mtain-me11.r1000.mx.aol.com [172.29.96.147]) by air-de08.mail.aol.com (v127_r1.1) with ESMTP id MAILINDE081-5ebe4b82e13539c; Mon, 22 Feb 2010 14:55:33 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-me11.r1000.mx.aol.com (Internet Inbound) with ESMTP id DD959380000AE; Mon, 22 Feb 2010 14:55:31 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NjeMY-00049T-Q7 for rs_out_1@blacksheep.org; Mon, 22 Feb 2010 19:54:38 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NjeMY-00049K-CS for rsgb_lf_group@blacksheep.org; Mon, 22 Feb 2010 19:54:38 +0000 Received: from mail-bw0-f215.google.com ([209.85.218.215]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NjeMV-0004xS-D0 for rsgb_lf_group@blacksheep.org; Mon, 22 Feb 2010 19:54:38 +0000 Received: by bwz7 with SMTP id 7so2037816bwz.4 for ; Mon, 22 Feb 2010 11:54:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=3DjWPlrA71e0nJKDGblY3Tfa9xOlVBwU6MZ7Dr6Xgg4=; b=LS1bz1hxD6uKUa3+WbNtg2wUvmNbxILHreOtvXTsrsJ6UdBOtkoFCtCtz6v9vGx9XQ ld+43lcXGdpRHFiGP4i8jUde2jjearCQCqngMKuxpStZsS6dJPwACRm9aheD3ZQqQBey 61N2Fgk+mftz7stNiKr6YWi2EaeRUs+Q0VIJE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=UTDv3k977S15p5m75JpwuhKjzBZJO8LRy/L/OHp21uwJ+NcaQu26rVQ4RbAIiYgsM8 Ldr9GMvM9LVP6EXNvYVeTuud4Oi63zJpXgi3tpgfV7rt/Acm1T5p/MntGhTi5j2E+H+z PQJg8YI7JnMqjLlHhS1tonoDU/zLzK1WKc1Bg= MIME-Version: 1.0 Received: by 10.204.16.66 with SMTP id n2mr2506503bka.67.1266868469632; Mon, 22 Feb 2010 11:54:29 -0800 (PST) In-Reply-To: <201002221851390968.021247E4@smtp2.numeo.fr> References: <32098189.1842344.1266827344324.JavaMail.fmail@mwmweb080> <20100222112301.D8324F3862@smtps02.kuleuven.be> <201002221851390968.021247E4@smtp2.numeo.fr> Date: Mon, 22 Feb 2010 19:54:29 +0000 Message-ID: <9afca2641002221154p40cccc31x1e19f2b0095ac73e@mail.gmail.com> From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: AW: LF: AW: Beaconing on 8.79 kHz in QRSS Content-Type: multipart/alternative; boundary=00032555412a1c10fc048035cd56 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=HTML_FONTCOLOR_UNSAFE, HTML_MESSAGE 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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m273.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d60934b82e133525e X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --00032555412a1c10fc048035cd56 Content-Type: text/plain; charset=ISO-8859-1 Presumably the 2.5kms on 87 or 27kHz was using USB John, or at least in USB bandwidths? Assuming a mode like QRSS30 or QRSS60, this would imply that considerably further DX would be possible, even allowing for an inverse cube attenuation rate. I wonder if anyone has any lists of DX achieved using induction mode communications? 73s Roger G3XBM On 22 February 2010 17:51, John RABSON wrote: > If I recall correctly, G0AKN (now SK) tried audio frequencies as well as 73 > and 136 kHz. G8DSU, who monitors this list, may have more information. An > article by G0AKN on this subject appeared in the Jan-Feb.1999 issue of the > AMRAD newsletter. More information may be found by searching online for > G0AKN. > > Most cave radio work takes place on 87kHz USB although we have sometimes > used frequencies as low as 27kHz. The maximum range we have achieved with a > 4 W transmitter is about 2 1/2 kilometres. > > 73 > John Rabson > F5VLF > 58800 Cervon > France > JN17vg > > > > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --00032555412a1c10fc048035cd56 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Presumably the 2.5kms on 87 or 27kHz was using USB John, or at least in US= B bandwidths? Assuming a mode like QRSS30 or QRSS60, this would imply that= considerably further DX would be possible, even allowing for an inverse= cube attenuation rate.

I wonder if anyone has any lists of DX achieved using induction mode= communications?

73s
Roger G3XBM

On 22 February 2010 17:51, John RABSON <john.rabson@numeo.fr> wrote:
If I recall cor= rectly, G0AKN (now SK) tried audio frequencies as well as 73 and 136 kHz.= =A0G8DSU, who monitors this list, may have more information. =A0An articl= e by G0AKN on this subject appeared in the Jan-Feb.1999 =A0issue of the AM= RAD newsletter. =A0More information may be found by searching online for= G0AKN.

Most cave radio work takes place on 87kHz USB although we have sometimes= used frequencies as low as 27kHz. =A0The maximum range we have achieved= with a 4 W transmitter is about 2 1/2 kilometres.

73
John Rabson
F5VLF
58800 Cervon
France
JN17vg








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http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
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