Return-Path: Received: from mtain-df10.r1000.mx.aol.com (mtain-df10.r1000.mx.aol.com [172.29.64.222]) by air-db09.mail.aol.com (v129.4) with ESMTP id MAILINDB093-864b4d0233b039f; Fri, 10 Dec 2010 09:05:36 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-df10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 16E433800016A; Fri, 10 Dec 2010 09:05:33 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PR3aR-0006Dc-2g for rs_out_1@blacksheep.org; Fri, 10 Dec 2010 14:04:39 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PR3aQ-0006DT-FV for rsgb_lf_group@blacksheep.org; Fri, 10 Dec 2010 14:04:38 +0000 Received: from cavuit01.kulnet.kuleuven.be ([134.58.240.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PR3aL-0002WM-Jp for rsgb_lf_group@blacksheep.org; Fri, 10 Dec 2010 14:04:36 +0000 Received: from smtps01.kuleuven.be (smtpshost01.kulnet.kuleuven.be [134.58.240.74]) by cavuit01.kulnet.kuleuven.be (Postfix) with ESMTP id DB9977B808F for ; Fri, 10 Dec 2010 15:04:24 +0100 (CET) Received: from ICTS-S-HUB-N4.luna.kuleuven.be (icts-s-hub-n4.luna.kuleuven.be [10.112.9.14]) by smtps01.kuleuven.be (Postfix) with ESMTP id BCC1431E702 for ; Fri, 10 Dec 2010 15:04:24 +0100 (CET) Received: from ICTS-S-EXC2-CA.luna.kuleuven.be ([10.112.11.13]) by ICTS-S-HUB-N4.luna.kuleuven.be ([10.112.9.14]) with mapi; Fri, 10 Dec 2010 15:04:25 +0100 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Date: Fri, 10 Dec 2010 15:02:34 +0100 Thread-Topic: Earth mode tests (8.76kHz) Thread-Index: AcuYci1+fyHZX6uMSXq/gxOsazw53gAALdyp Message-ID: References: In-Reply-To: Accept-Language: nl-NL, nl-BE Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: nl-NL, nl-BE MIME-Version: 1.0 X-KULeuven-Information: Katholieke Universiteit Leuven X-KULeuven-Scanned: Found to be clean X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: RE: Earth mode tests (8.76kHz) Content-Type: multipart/alternative; boundary="_000_BF4A524700075746A6467658DFC7102C886FDD7516ICTSSEXC2CAlu_" 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,TO_ADDRESS_EQ_REAL 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: 3039ac1d40de4d0233ad61d0 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --_000_BF4A524700075746A6467658DFC7102C886FDD7516ICTSSEXC2CAlu_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable > but fun experiments nonetheless Roger, that's the spirit, it's a hobby so it should be fun. Good luck with the VLF experiments. 73, Rik ON7YD - OR7T ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.or= g] namens Roger Lapthorn [rogerlapthorn@gmail.com] Verzonden: vrijdag 10 december 2010 14:53 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: Earth mode tests (8.76kHz) Today I did a test receiving my 8.76kHz QRSS3 VLF signal 5.1km away from= the home comparing reception using (a) an 80cm loop antenna and (b) a sma= ll earth electrode antenna (14m spacing) using a variety of pre-amps. Alt= hough quite solid reception (17dB S/N in 0.18Hz BW) was achieved using the= loop laying flat on the ground, there was absolutely nothing detected usi= ng the earth electrodes which were pushed into the soil either side of the= road, which was both surprising and disappointing. I used the very same= pre-amp in both cases and also tried the lo-Z input 8-9kHz tuned pre-amp= with the earth electrodes that successfully copied DK7FC at 648km last we= ekend on the earth electrodes at home. Several possibilities for the failure with the earth electrodes at the RX= site: * The electrode spacing was far too small * The barbecue skewers used as RX electrodes were too short and not mak= ing decent soil contact * The soil was too wet, so the pick-up (effective loop area in the grou= nd) was lower than with dry, low conductivity soil; the test site is in th= e fens where the soil is a dark peat. Next step is to repeat the test up on the chalk uplands to the south of th= e QTH at about 4km distance where soil conductivity will be lower and to= try a larger earth electrode spacing on receive. When compared with the 2873km DX by Stefan this is nothing to get too exci= ted about, but fun experiments nonetheless. 73s Roger G3XBM -- g3xbm-qrp.blogspot.com/ www.g3xbm.co.uk www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --_000_BF4A524700075746A6467658DFC7102C886FDD7516ICTSSEXC2CAlu_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
> but fun experiments nonetheless
 
Roger,
 
that's the spirit, it's= a hobby so it should be fun.
 
Good luck with the VLF= experiments.
 
73, Rik  ON7YD - OR= 7T
 
Van: owner-rsgb_= lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Roger= Lapthorn [rogerlapthorn@gmail.com]
Verzonden: vrijdag 10 december 2010 14:53
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: Earth mode tests (8.76kHz)

Today I did a test receiving my 8.76kHz QRSS3 VLF signal 5.1km away= from the home comparing reception using (a) an 80cm loop antenna and (b)= a small earth electrode antenna (14m spacing) using a variety of pre-amps= .  Although quite solid reception (17dB S/N in 0.18Hz BW) was achieved using the loop laying flat on the ground,= there was absolutely nothing detected using the earth electrodes which we= re pushed into the soil either side of the road, which was both surprising= and disappointing. I used the very same pre-amp in both cases and also tried the lo-Z input 8-9kHz tuned pre= -amp with the earth electrodes that successfully copied DK7FC at 648km las= t weekend on the earth electrodes at home.

Several possibilities for the failure with the earth electrodes at the RX= site:
  • The electrode spacing was far too small
  • The barbecue skewers= used as RX electrodes were too short and not making decent soil contact
  • The soil was too wet, so the pick-up (effective loop area in the= ground) was lower than with dry, low conductivity soil; the test site is= in the fens where the soil is a dark peat.
Next step is to repeat the test up on the chalk uplands to the south of th= e QTH at about 4km distance where soil conductivity will be lower and to= try a larger earth electrode spacing on receive.

When compared with the 2873km DX by Stefan this is nothing to get= too excited about, but fun experiments nonetheless.

73s
Roger G3XBM

--
g3xbm-qrp.blo= gspot.com/
www.g3xbm.co.uk www.youtub= e.com/user/g3xbm
G3XBM   GQR= P 1678    ISWL G11088
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