Return-Path: Received: from mtain-mk04.r1000.mx.aol.com (mtain-mk04.r1000.mx.aol.com [172.29.97.136]) by air-ma09.mail.aol.com (v129.4) with ESMTP id MAILINMA092-b5354d37ebe23da; Thu, 20 Jan 2011 03:01:38 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mk04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 15A7838000090; Thu, 20 Jan 2011 03:01:36 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PfpRE-000666-29 for rs_out_1@blacksheep.org; Thu, 20 Jan 2011 08:00:12 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PfpRD-00065x-6H for rsgb_lf_group@blacksheep.org; Thu, 20 Jan 2011 08:00:11 +0000 Received: from filter02.i-online.fr ([195.200.78.9]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PfpRC-00027O-7i for rsgb_lf_group@blacksheep.org; Thu, 20 Jan 2011 08:00:11 +0000 Received: from smtp.qtxt.dns-iol.com ([195.200.78.13]) by filter02.i-online.fr (IceWarp 10.0.7 (2010-02-10)) with ESMTP (SSL) id DIB49949 for ; Thu, 20 Jan 2011 08:59:49 +0100 Received: (qmail 1096 invoked by uid 507); 20 Jan 2011 08:59:58 +0100 Received: from unknown (HELO ?192.168.1.103?) (john.rabson@numeo.fr@217.67.155.178) by smtp.qtxt.dns-iol.com with SMTP; 20 Jan 2011 08:59:58 +0100 Mime-Version: 1.0 (Apple Message framework v1082) From: John Rabson X-Priority: 3 In-Reply-To: <042CEEE45B334986AD59DA9C01BF6E13@White> Date: Thu, 20 Jan 2011 09:00:00 +0100 Message-Id: <2D8E4DB8-81D5-4671-B338-4E7E0C3EDD6B@numeo.fr> References: <4D3729FC.6080509@iup.uni-heidelberg.de> <042CEEE45B334986AD59DA9C01BF6E13@White> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.1082) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: VLF: PSK on 3.3 kHz by cavers Content-Type: multipart/alternative; boundary=Apple-Mail-5--624379573 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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-sid: 3039ac1d61884d37ebe027bf X-AOL-IP: 195.171.43.25 --Apple-Mail-5--624379573 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Using about 4W RF on 87kHz USB, we found that using an earth electrode sys= tem underground insted of a small loop gave up to 31dB stronger signal on= the surface (Kingsdale Master Cave valley entrance in Yorkshire), and our= best cave to surface DX was 1.5km (in the Trou Qui Souffle in the Vercors= ). John F5VLF/G3PAI Cave Radio & Electronics Group, British Cave Research Association On 19 Jan 2011, at 23:30CET, Markus Vester wrote: > Hi Stefan, thats interesting! Any idea of what's inside that long grey= tube? I would presume it's a coil wound around an iron powder or ferrite= bar, kind of large loopstick. Reminds me of our recent discussion about= possible long and thin high-voltage loading coils... > =20 > Best 73, > Markus (DF6NM) >=20 > =20 > From: Stefan Sch=E4fer > Sent: Wednesday, January 19, 2011 7:14 PM > To: rsgb_lf_group@blacksheep.org > Subject: VLF: PSK on 3.3 kHz by cavers >=20 > VLF, >=20 > A friend of me, F1BKM has told me about a recent french VLF experiment= =20 > on 3.3 kHz. It seems they crossed 300m in PSK31 at 3.3 kHz. > Many photos are visible at=20 > http://f6kcz.free.fr/Actualites/2011/Carrieres%20Fleury/Carrieres%20Fleu= ry.htm >=20 > Looks interesting but an earth loop may be better here. But the system= =20 > is very /p! >=20 > 73, Stefan/DK7FC >=20 --Apple-Mail-5--624379573 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 Using about 4W RF on 87k= Hz USB, we found that using an earth electrode system underground insted= of a small loop gave up to 31dB stronger signal on the surface (Kingsdale= Master Cave valley entrance in Yorkshire), and our best cave to surface= DX was 1.5km (in the Trou Qui Souffle in the Vercors).

John F5VLF/G3PAI
Cave Radio & Electronics Group, British Ca= ve Research Association

On 19 Jan 2011, at 23:30CE= T, Markus Vester wrote:

Hi Stefan, thats interesting! Any ide= a of what's=20 inside that long grey tube? I would presume it's a coil wound around an ir= on=20 powder or ferrite bar, kind of large loopstick. Reminds me of our recent= =20 discussion about possible long and thin high-voltage loading=20 coils...
 
Best 73,
Markus (DF6NM)

 
Sent: Wednesday, January 19, 2011 7:14 PM
Subject: VLF: PSK on 3.3 kHz by cavers

VLF,

A friend of me, F1BKM has told me about a recen= t=20 french VLF experiment
on 3.3 kHz. It seems they crossed 300m in PSK31= at 3.3=20 kHz.
Many photos are visible at
http://f6kcz.free.fr/Actualites= /2011/Carrieres%20Fleury/Carrieres%20Fleury.htm

Looks=20 interesting but an earth loop may be better here. But the system
is ve= ry=20 /p!

73, Stefan/DK7FC


=3D --Apple-Mail-5--624379573--