Return-Path: Received: from mtain-db07.r1000.mx.aol.com (mtain-db07.r1000.mx.aol.com [172.29.64.91]) by air-de08.mail.aol.com (v129.4) with ESMTP id MAILINDE083-5ec04c21bb4115c; Wed, 23 Jun 2010 03:44:01 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-db07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5BE86380000A3; Wed, 23 Jun 2010 03:43:58 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ORKbr-0002u1-Ph for rs_out_1@blacksheep.org; Wed, 23 Jun 2010 08:42:59 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ORKbr-0002ts-7g for rsgb_lf_group@blacksheep.org; Wed, 23 Jun 2010 08:42:59 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1ORKbq-0006Al-1q for rsgb_lf_group@blacksheep.org; Wed, 23 Jun 2010 08:42:59 +0100 Received: by bwz15 with SMTP id 15so805455bwz.16 for ; Wed, 23 Jun 2010 00:42:57 -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=xu32AuE/he8G57Rj5UXJJEEEikec30SvkFC2i4pZg/o=; b=U9MBZFixJZmHnhPjLohtL+yelsIQiWIXZsvp+pe6L1U2OiXIHzAYxm/f0CFTxBe1EZ W/vv+pPJyd4DbJTgGPV/FxqEJYFONFa/mq1bE2LUggjaLylS8XGscZcL+wwxaWUuR+lr lg4ZM0dOI3A7n9NVg/zVhKnO/AP3GGLIJnmwk= 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=r+2hKk/nulTl438rxvxFvXZOkc9MmAn8+7eK/n+h7qCu2XDDbnrfK+Twnp4+Ucr42e fXWx+leNmlbpMbnsCYAxl8Bt0HA8scAWns97hp4lE9psX4Lb4FOil5S9w/a8KhDfLoKj nCMRFOGZzpK1HUP7hnw/3WEbMit4VLcO44LqY= MIME-Version: 1.0 Received: by 10.204.140.4 with SMTP id g4mr5133113bku.166.1277278976917; Wed, 23 Jun 2010 00:42:56 -0700 (PDT) Received: by 10.204.100.69 with HTTP; Wed, 23 Jun 2010 00:42:56 -0700 (PDT) In-Reply-To: References: Date: Wed, 23 Jun 2010 08:42:56 +0100 Message-ID: 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: LF: RE: VLF QRP Earth mode: 5.1km DX tonight but no such thing as a free lunch Content-Type: multipart/alternative; boundary=0015174c0f74b2c0630489adaf81 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, 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-d254.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d405b4c21bb3e7b5c X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --0015174c0f74b2c0630489adaf81 Content-Type: text/plain; charset=ISO-8859-1 Rik (et al), One earth rod in the sea at each end and another driven into the chalk rock 300m inland at each end and would almost *guarantee* a QSO on 1kHz across the channel by earth-mode. Anyone crossing the channel would be able to detect the signal with a loop in a boat. Two rods in the sea at each end would not work. Also, you do wonder with the network of gas pipes, water pipes, electricity pylons, phone lines etc criss-crossing vast swathes of countryside just how far "utility assisted" (for the want of a better term) earth mode VLF comms could travel. From my own QRP tests this week I conclude a LOT further than I'd previously thought possible. Of course no direct physical connection is needed, just the ability to induce power into these by placing wire loops or earth electrode loops nearby. This raises another point. However unintentionally, 136kHz, 500kHz and 1.8MHz signals must, at times, couple into utilities and be "helped" to radiate more effectively by the presence of cables and pipes. I am now almost sure that the same mechanism used to conduct my 838Hz signal a very long way last night must have helped my 500kHz WSPR signal cross the UK last weekend: there is a signal flowing in the earth electrode "loop in the ground" as well as a signal flowing around the streets via copper water pipes. Whether the mechanism at 500kHz or 137kHz is as a result of a loop or a very long e-field antenna (the copper pipes in the streets) just below the surface of the earth is open to debate. Fascinating. 73s Roger G3XBM On 23 June 2010 08:15, Rik Strobbe wrote: > Yet another thought: > > salt water is a rather good conductor. > What about a couple of rods into the sea near Dover and another pair near > Cap Griz Nez ? > Distance is 34 km. > > 73, Rik ON7YD > > ------------------------------ > *Van:* owner-rsgb_lf_group@blacksheep.org [ > owner-rsgb_lf_group@blacksheep.org] namens Rik Strobbe [ > Rik.Strobbe@fys.kuleuven.be] > *Verzonden:* woensdag 23 juni 2010 9:00 > *Aan:* rsgb_lf_group@blacksheep.org > *Onderwerp:* LF: RE: VLF QRP Earth mode: 5.1km DX tonight but no such > thing as a free lunch > > > 1. *At greater distances (3-5kms) the signal reaches its destination by > conduction through the ground aided by pipes in the roads and with inductive > coupling into the loop at the RX.* > > Roger, > > very interesting. > There are huge gas pipelines running across the country (and even across > Europe). > I wonder how far one would get with a ground antenna near one of these. > The 2 rods of the ground antenna each at one side of the pipeline would > give optimal coupling. > > 73, Rik ON7YD > > > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --0015174c0f74b2c0630489adaf81 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Rik (et al),

One earth rod in the sea at each end and another drive= n into the chalk rock 300m inland at each end and would almost guarante= e a QSO on 1kHz across the channel by earth-mode. Anyone crossing the= channel would be able to detect the signal with a loop in a boat. Two rod= s in the sea at each end would not work.

Also, you do wonder with the network of gas pipes, water pipes, electr= icity pylons, phone lines etc criss-crossing vast swathes of countryside= just how far "utility assisted" (for the want of a better term)= earth mode VLF comms could travel. From my own QRP tests this week I conc= lude a LOT further than I'd previously thought possible. Of course no= direct physical connection is needed, just the ability to induce power in= to these by placing wire loops or earth electrode loops nearby.

This raises another point. However unintentionally, 136kHz, 500kHz and= 1.8MHz signals must, at times, couple into utilities and be "helped&= quot; to radiate more effectively by the presence of cables and pipes. I= am now almost sure that the same mechanism used to conduct my 838Hz signa= l a very long way last night must have helped my 500kHz WSPR signal cross= the UK last weekend:=A0 there is a signal flowing in the earth electrode= "loop in the ground" as well as a signal flowing around the str= eets via copper water pipes. Whether the mechanism at 500kHz or 137kHz is= as a result of a loop or a very long e-field antenna (the copper pipes in= the streets)=A0 just below the surface of the earth is open to debate.
Fascinating.

73s
Roger G3XBM



On 23 June 2010 08:15, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be&g= t; wrote:
Yet another thought:
=A0
salt water is a rather good conducto= r.
What about a couple of rods into the= =A0sea near Dover and another pair=A0near Cap Griz Nez ?
Distance is 34 km.
=A0
73, Rik=A0 ON7YD
=A0
Van: owner-rsgb_lf= _group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Ri= k Strobbe [Rik.Strobbe@fys.kuleuven.be]
Verzonden: woensdag 23 juni 2010 9:00
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: RE: VLF QRP Earth mode: 5.1km DX tonight but no such= thing as a free lunch

  1. At greater distances (3-5kms) the signal re= aches its destination by conduction through the ground aided by pipes in= the roads and with inductive coupling into the loop at the RX.=
Roger,=
=A0
very interesting.=
There are huge gas pipel= ines running across the country (and even across Europe).
I wonder how far one wou= ld get with a ground antenna near one of these.
The 2 rods of the ground= antenna each at one side of the pipeline would give optimal coupling.
=A0
73, Rik=A0 ON7YD<= /div>
=A0
=A0
=A0
=A0



--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--0015174c0f74b2c0630489adaf81--