Return-Path: Received: from mtain-db09.r1000.mx.aol.com (mtain-db09.r1000.mx.aol.com [172.29.64.93]) by air-da08.mail.aol.com (v129.4) with ESMTP id MAILINDA082-86184c192ff81a2; Wed, 16 Jun 2010 16:11:36 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-db09.r1000.mx.aol.com (Internet Inbound) with ESMTP id 69091380002CB; Wed, 16 Jun 2010 16:11:31 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OOywL-0005CL-Cn for rs_out_1@blacksheep.org; Wed, 16 Jun 2010 21:10:25 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OOywK-0005CC-Sd for rsgb_lf_group@blacksheep.org; Wed, 16 Jun 2010 21:10:24 +0100 Received: from smtp.qtxt.dns-iol.com ([195.200.78.13]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OOywG-0007nk-HS for rsgb_lf_group@blacksheep.org; Wed, 16 Jun 2010 21:10:24 +0100 Received: (qmail 22531 invoked by uid 507); 16 Jun 2010 22:09:48 +0200 Received: from unknown (HELO ?192.168.1.101?) (john.rabson@numeo.fr@217.67.155.178) by smtp.qtxt.dns-iol.com with SMTP; 16 Jun 2010 22:09:48 +0200 From: John Rabson Mime-Version: 1.0 (Apple Message framework v1078) Date: Wed, 16 Jun 2010 22:11:57 +0200 In-Reply-To: To: rsgb_lf_group@blacksheep.org References: Message-Id: <648287CF-49D0-4E2E-BCE5-B20F634C9384@numeo.fr> X-Mailer: Apple Mail (2.1078) X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276 Content-Type: multipart/alternative; boundary=Apple-Mail-1--88309876 Subject: Re: LF: RE: Who needs antennas! - success with ground electrodes on 500kHz X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.6 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, HTML_MESSAGE,MAILTO_TO_SPAM_ADDR 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: 3039ac1d405d4c192ff376aa X-AOL-IP: 193.82.116.20 --Apple-Mail-1--88309876 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Some years ago, the Cave Radio & Electronics Group was conducting tests on= 87 kHz between surface and underground at Roger Kirk Cave near Ribblehead= viaduct in Yorkshire. After we had finished the tests I tuned the surface= receiver up to 136 and got very good signals from EI0CF. Unfortunately th= ere was no mobile phone service at the site so we could not let him know= immediately. We did send him a QSL card. 73 John F5VLF/G3PAI =20 On 16 Jun 2010, at 21:51CEST, Roger Lapthorn wrote: > Correction - I'm also copying PE1GRL at -18dB S/N using the earth electr= ode set-up! >=20 > 73s > Roger G3XBM >=20 > On 16 June 2010 20:43, Dave G3WCB wrote: > That's pretty amazing. You must have really bad soil conductivity. Did= you try receiving on the earth-loop antenna? > =20 > Would the technique work on 137 kHz, I wonder. > =20 > 73, Dave G3WCB IO91RM, nr Windsor, S.E. England > -----Original Message----- > From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@bla= cksheep.org]On Behalf Of Roger Lapthorn > Sent: 16 June 2010 20:11 > To: rsgb_lf_group@blacksheep.org > Subject: LF: Who needs antennas! - success with ground electrodes on 500= kHz >=20 > Well, I'm amazed.=20 >=20 > This evening I connected my 500kHz transverter straight to the two conne= ctions of my sub-9kHz grounded electrodes and TXed WSPR. No attempt was ma= de to match anything on the assumption that the two electrodes system look= ed not too far from 50 ohms resistive as measured between 1-9kHz.. Pout fr= om the IRF510 is around 5W. What happened?=20 >=20 > Three people copied me - M0BMU, G7NKS and M0JXM with reports between -21= and -28dB S/N. The wire to the furtherest ground rod is at most 20m long= and most of the way it is 1.5m above ground. Once again, this must be act= ing as a pretty effective loop mostly within the ground. Screen grab of= the WSPR log attached. >=20 > So, if you live on clunchy chalk soils like me then don't worry too much= about big antennas, :-) >=20 > 73s > Roger G3XBM >=20 > --=20 > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 >=20 >=20 >=20 > --=20 > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 --Apple-Mail-1--88309876 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Some years ago, the Cave= Radio & Electronics Group was conducting tests on 87 kHz between surf= ace and underground at Roger Kirk Cave near Ribblehead viaduct in Yorkshir= e. After we had finished the tests I tuned the surface receiver up to 136= and got very good signals from EI0CF. Unfortunately there was no mobile= phone service at the site so we could not let him know immediately. We di= d send him a QSL card.

 73
John F5VLF/G3= PAI
 
On 16 Jun 2010, at 21:51CEST, Roger Lapt= horn wrote:

Correction - I'm also copying PE1GRL at -18dB S/N using= the earth electrode set-up!

73s
Roger G3XBM

On 16 June 2010 20:43, Dave G3WCB <<= a href=3D"mailto:ganymede444@btopenworld.com">ganymede444@btopenworld.com<= /a>> wrote:
That's=20 pretty amazing. You must have really bad soil conductivity. Did you try=20 receiving on the earth-loop antenna?
 
Would=20 the technique work on 137 kHz, I wonder.
 
73,=20 Dave G3WCB IO91RM, nr Windsor, S.E. England
-----Or= iginal Message-----
From:=20 = owner-rsgb_lf_group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Roger= =20 Lapthorn
Sent: 16 June 2010 20:11
To:=20 rsgb_l= f_group@blacksheep.org
Subject: LF: Who needs antennas! -=20 success with ground electrodes on 500kHz

Well, I'm= amazed.=20

This evening I connected my 500kHz transverter straight to the= two=20 connections of my sub-9kHz grounded electrodes and TXed WSPR. No attempt= was=20 made to match anything on the assumption that the two electrodes system= looked=20 not too far from 50 ohms resistive as measured between 1-9kHz.. Pout fro= m the=20 IRF510 is around 5W. What happened?

Three people copied me -=20 M0BMU, G7NKS and M0JXM with reports between -21 and -28dB S/N. The wire= to the=20 furtherest ground rod is at most 20m long and most of the way it is 1.5m= above=20 ground. Once again, this must be acting as a pretty effective loop mostl= y=20 within the ground.  Screen grab of the WSPR log attached.

So= , if=20 you live on clunchy chalk soils like me then don't worry too much about= big=20 antennas, :-)

73s
Roger G3XBM

--
http://g3xbm-qr= p.blogspot.com/
http://www.g3xbm.co.uk
http://www= .youtube.com/user/g3xbm
G3XBM=20    GQRP 1678      ISWL=20 G11088



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

=3D --Apple-Mail-1--88309876--