Return-Path: Received: from mtain-de09.r1000.mx.aol.com (mtain-de09.r1000.mx.aol.com [172.29.64.209]) by air-da03.mail.aol.com (v129.4) with ESMTP id MAILINDA032-86134c3f4ea71e0; Thu, 15 Jul 2010 14:08:39 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-de09.r1000.mx.aol.com (Internet Inbound) with ESMTP id 242A6380003F4; Thu, 15 Jul 2010 14:08:37 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OZSq3-00005y-Lc for rs_out_1@blacksheep.org; Thu, 15 Jul 2010 19:07:15 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OZSq3-00005p-2T for rsgb_lf_group@blacksheep.org; Thu, 15 Jul 2010 19:07:15 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OZSq1-0005PN-N7 for rsgb_lf_group@blacksheep.org; Thu, 15 Jul 2010 19:07:15 +0100 Received: by bwz13 with SMTP id 13so915037bwz.16 for ; Thu, 15 Jul 2010 11:07:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=ztv4bZHzH3PSGVakSOf+s/613aSWHi1EQXOInNHFmrc=; b=Ln6TSPWSO43kWd8FtwOZTtehlnQH9T3QvX8TJxxHn1NtU2mCOdF9AF+yjFteJiO1GO lfap/KOiYUItOQqqAzX/6mQrY2K+XOLeCvxz3Xekfx+7Jyxzr65VGPx9ejDosTgEnLjQ xFupdmnRUBBCDjTp90ldrJM0kJ6TFqfJZ/Ihs= 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=GkP/t3sdW4X56T54fAGxmnISHOzqdKqaKfM2hQ8VdRv5gDD1UCLSuiE8M6ZxJklgin AWmpYYQ5GFEFQazpwQBUtK+qje4JPIMFuwb7cvD6Du1/GNmFdXIfefpoESK9VcfQqeKb Xaq0HbxZyKXTZCBA/dmXcVhDVxbqjG5JOvhjs= MIME-Version: 1.0 Received: by 10.204.134.133 with SMTP id j5mr14771323bkt.159.1279217232161; Thu, 15 Jul 2010 11:07:12 -0700 (PDT) Received: by 10.204.122.148 with HTTP; Thu, 15 Jul 2010 11:07:11 -0700 (PDT) In-Reply-To: <3F71CB69-5F2E-4BEE-BB5E-651DA77CC39E@numeo.fr> References: <4C363DCD.303@iup.uni-heidelberg.de> <4C3650A1.6040104@iup.uni-heidelberg.de> <4C3DA75D.80407@iup.uni-heidelberg.de> <263121BD51374246B3F184A43B2E9619@JimPC> <4C3E27D4.3060407@iup.uni-heidelberg.de> <3F71CB69-5F2E-4BEE-BB5E-651DA77CC39E@numeo.fr> Date: Thu, 15 Jul 2010 19:07:11 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001 Subject: Re: LF: RE: DLF passive received with earth antenna Content-Type: multipart/alternative; boundary=0015173ff3acb6abdf048b70f825 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-m204.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40d14c3f4ea51433 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --0015173ff3acb6abdf048b70f825 Content-Type: text/plain; charset=ISO-8859-1 This sounds an interesting talk. Where is this conference being held please? Perhaps with Heyphones and Nicola systems working in the 40-90kHz region these antennas do behave differently. At 500kHz I'm convinced the earth electrode structure behaves as a loop based on the reports I've received and directionality. I suspect the same is true at 136kHz . At ELF/VLF I think the earth electrode pair must act in several ways simultaneously. (a) As an induction loop. This certainly ties up with behaviour and loop orientation locally in my experiments away from buried cables. (b) As a means of producing a potential difference in the ground for earth mode (conduction) communication. Again, this is how I understand my "utilities assisted DX" is being achieved on 838Hz with the signal being largely conducted along buried pipework and cables and the last few metres being inductively coupled into my loop receiver. I can't see how else just 4W can get so far. (b) As an inefficient and lossy dipole radiating a tiny signal. It would be most interesting to read about the ELF antennas used for Project Sanguine and the theory behind these. These (miles long) antennas were grounded at each end and the grounding was important for the system to radiate an ELF signal detectable in the deep oceans at 76Hz. Has Dr Gibson written anything already to give us a clue what he thinks is going on? 73s Roger G3XBM On 15 July 2010 17:52, John Rabson wrote: > Members of the Cave Radio & Electronics Group have been using and > investigating earth loop antennas for some time. The theoretical basis of > such an antenna has not been clear to us, but Dr David Gibson of CREG is > proposing to give the following lecture at the Hidden Earth conference in > the UK this autumn. > > How earth-current antennas really work > -------------------------------------- > With cave radio equipment such as the HeyPhone and Nicola system there > has been a trend away from the use of induction loop antennas towards > earth-current antennas, i.e. long wires grounded at both ends. However, > the popular explanation for how these antennas work is fallacious. They > do not operate by allowing the current to flow in a 'big loop' in the > ground and in fact, they do not depend, fundamentally, on current flow > in the ground at all. > > The fact that the popular explanation is wrong is important because, if > we do not understand how the antenna works, it is difficult to know the > best way to use it, or how to design a better one. Back in 2003, I wrote > an article for the CREG journal entitled 'What We Don't Know About > Earth-Current Propagation'. It has taken me some time to get to grips > with the problem but this talk will now go some way to filling in the > gaps in this knowledge and will describe a method of experimentally > rating earth-current antennas for effectiveness. > > -- > David Gibson > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --0015173ff3acb6abdf048b70f825 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable This sounds an interesting talk. Where is this conference being held pleas= e?

Perhaps with Heyphones and Nicola systems working in the 40-90k= Hz region these antennas do behave differently.=A0 At 500kHz I'm convi= nced the earth electrode structure behaves as a loop based on the reports= I've received and directionality. I suspect the same is true at 136kH= z .

At ELF/VLF I think the earth electrode pair must act in several ways= =20 simultaneously.

(a) As an inducti= on loop. This certainly ties up with behaviour and loop orientation locall= y in my experiments away from buried cables.

(b) As a means of prod= ucing a potential difference in the ground for earth mode (conduction) com= munication. Again, this is how I understand my "utilities assisted DX= " is being achieved on 838Hz with the signal being largely conducted= along buried pipework and cables and the last few metres being inductivel= y coupled into my loop receiver. I can't see how else just 4W can get= so far.

(b) As an inefficient and lossy dipole radiating a tiny signal.

It would be most interesting to read about the ELF antennas used= for Project Sanguine and the theory behind these. These (miles long) ante= nnas were grounded at each end and the grounding was important for the sys= tem to radiate an ELF signal detectable in the deep oceans at 76Hz.

Has Dr Gibson written anything already to give us a clue what he think= s is going on?

73s
Roger G3XBM


On 15 July 2010 17:52, John Rabson <john.rabson@numeo.fr> wrote:
Members of the= Cave Radio & Electronics Group have been using and investigating eart= h loop antennas for some time. The theoretical basis of such an antenna ha= s not been clear to us, but Dr David Gibson of CREG is proposing to give= the following lecture at the Hidden Earth conference in the UK this autum= n.

How earth-current antennas really work
--------------------------------------
With cave radio equipment such as the HeyPhone and Nicola system there
has been a trend away from the use of induction loop antennas towards
earth-current antennas, i.e. long wires grounded at both ends. However, the popular explanation for how these antennas work is fallacious. They do not operate by allowing the current to flow in a 'big loop' in= the
ground and in fact, they do not depend, fundamentally, on current flow
in the ground at all.

The fact that the popular explanation is wrong is important because, if we do not understand how the antenna works, it is difficult to know the best way to use it, or how to design a better one. Back in 2003, I wrote an article for the CREG journal entitled 'What We Don't Know About=
Earth-Current Propagation'. It has taken me some time to get to grips<= br> with the problem but this talk will now go some way to filling in the
gaps in this knowledge and will describe a method of experimentally
rating earth-current antennas for effectiveness.

--
David Gibson




--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM=A0 =A0 GQRP 1678=A0 =A0 =A0 ISWL G11088
--0015173ff3acb6abdf048b70f825--