Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mh05.r1000.mx.aol.com (Internet Inbound) with ESMTP id BBDB8380000B2; Mon, 8 Aug 2011 13:45:35 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QqTsa-0001d7-RJ for rs_out_1@blacksheep.org; Mon, 08 Aug 2011 18:44:44 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QqTsa-0001cy-B1 for rsgb_lf_group@blacksheep.org; Mon, 08 Aug 2011 18:44:44 +0100 Received: from out1.ip02ir2.opaltelecom.net ([62.24.128.238]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QqTsY-0003VA-1z for rsgb_lf_group@blacksheep.org; Mon, 08 Aug 2011 18:44:44 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AucAAJMfQE5cF/bN/2dsb2JhbAA5CpNWA4N/j014gTsFAQEFCAEBA0kCDx0BAQMFAgEDEQQBAQolFAEEGgYWCAYTCgECAgEBh14Cvg6DJ4MgBIJQhF2VQ4Z7 X-IronPort-AV: E=Sophos;i="4.67,338,1309734000"; d="scan'208,217";a="372574074" Received: from host-92-23-246-205.as13285.net (HELO xphd97xgq27nyf) ([92.23.246.205]) by out1.ip02ir2.opaltelecom.net with SMTP; 08 Aug 2011 18:44:31 +0100 Message-ID: <002901cc55f2$d098c060$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: Date: Mon, 8 Aug 2011 18:44:25 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: 1.095kHz earth mode test at 6km Content-Type: multipart/alternative; boundary="----=_NextPart_000_0026_01CC55FB.321F3500" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-SCORE: 0:2:438658080:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60d94e4020bf5eca X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_0026_01CC55FB.321F3500 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To day my lawn is covered with MOLE MOUNDS of soil. As far as I can see = all you are doing is driving the MOLE population up NORTH QRP es Underground earth mode induction seems to achieve little for big = effort !! The local Music Rave can be heard 19 miles away in Audio mode using loudspearkers, a 2 Kw amplifier and an Appliance = Operator !!! G3KEV ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Monday, August 08, 2011 2:45 PM Subject: LF: 1.095kHz earth mode test at 6km Today I repeated the earth mode (through the ground) "long carrier" = test of 17.7.11 this time at 1.095kHz rather than 8.760kHz. The same = test location was used in the fens not far from the River Cam. This is = now a very long way from home! As before, I got my XYL to cut the = carrier for periods of 1 or 2 minutes to positively identify my signal. = I need to automate this so she can continue to do the gardening.... 4 different receiving antenna arrangements were tested, using my low = impedance MPF102 tuned preamp into the PC:=20 (a) an earth electrode pair parallel with the road,=20 (b) an earth electrode pair diagonally across the road,=20 (c) a single turn loop in the road, and=20 (d) a 30t 80cm diameter loop at the edge of the road. =20 Best results were with (a) and (d). With (b) there was no detectable. = At 1.095kHz the signal was again around 10dB S/N in 11mHz bandwidth on = (a) and (d) and marginally weaker on (c). This is a similar result to = 8.76kHz although I was expecting the signal to be stronger at this lower = frequency. I'm now tempted to do an earth mode test at a higher = frequency, possibly 17.52kHz which I can still see with Spectran and = Spectrum Laboratory and I can derive with my 4060 divider circuit. Using = earth mode I believe I'll still be legal as very little radiated signal = can be present.=20 The image attached shows the signal with the RX earth electrodes = parallel to the road, i.e. set-up (a), at a distance of 6km from the = home QTH where the TX was running 5W into 20m spaced earth electrodes.=20 73s Roger G3XBM -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm https://sites.google.com/site/sub9khz/ ------=_NextPart_000_0026_01CC55FB.321F3500 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
To day my lawn is covered with MOLE MOUNDS of = soil. As far=20 as I can see all you are doing is driving the MOLE population up=20 NORTH
QRP es Underground earth mode induction seems to = achieve=20 little for big effort !! The local Music Rave can be heard 19 miles=20 away
in Audio mode using loudspearkers, a 2 Kw = amplifier and=20 an  Appliance Operator !!!
 
G3KEV
 
 
 
----- Original Message -----
From:=20 Roger=20 Lapthorn
Sent: Monday, August 08, 2011 = 2:45=20 PM
Subject: LF: 1.095kHz earth = mode test at=20 6km

Today I repeated the earth mode (through the ground) = "long=20 carrier" test of 17.7.11 this time at 1.095kHz rather than 8.760kHz. = The same=20 test location was used in the fens not far from the River Cam. This is = now a=20 very long way from home! As before, I got my XYL to cut the carrier = for=20 periods of 1 or 2 minutes to positively identify my signal. I need to = automate=20 this so she can continue to do the gardening....

4 different = receiving=20 antenna arrangements were tested, using my low impedance MPF102 tuned = preamp=20 into the PC:

(a) an earth electrode pair parallel = with the=20 road,
(b) an earth electrode pair diagonally across the road, =
(c) a=20 single turn loop in the road, and
(d) a 30t 80cm diameter loop at = the edge=20 of the road. 

Best results were with (a) and (d). = With (b)=20 there was no detectable. 

At 1.095kHz the signal was = again around=20 10dB S/N in 11mHz bandwidth on (a) and (d) and marginally weaker on = (c). This=20 is a similar result to 8.76kHz although I was expecting the signal to = be=20 stronger at this lower frequency.  I'm now tempted to do an earth = mode=20 test at a higher frequency, possibly 17.52kHz which I can still = see=20 with Spectran and Spectrum Laboratory and I can derive with my 4060 = divider=20 circuit. Using earth mode I believe I'll still be legal as very = little=20 radiated signal can be present.

The image attached shows the = signal=20 with the RX earth electrodes parallel to the road, i.e. set-up (a), at = a=20 distance of 6km from the home QTH where the TX was running 5W into 20m = spaced=20 earth electrodes.

73s
Roger G3XBM

--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3= xbm
https://sites.google.com/= site/sub9khz/

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