Return-Path: Received: from mtain-mc03.r1000.mx.aol.com (mtain-mc03.r1000.mx.aol.com [172.29.96.75]) by air-mc03.mail.aol.com (v129.4) with ESMTP id MAILINMC032-a8dc4c1bd7a0228; Fri, 18 Jun 2010 16:31:28 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mc03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9C12C380000CE; Fri, 18 Jun 2010 16:31:25 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OPiC0-0003cM-Hs for rs_out_1@blacksheep.org; Fri, 18 Jun 2010 21:29:36 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OPiC0-0003cD-55 for rsgb_lf_group@blacksheep.org; Fri, 18 Jun 2010 21:29:36 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OPiBx-00014F-RF for rsgb_lf_group@blacksheep.org; Fri, 18 Jun 2010 21:29:36 +0100 Received: by bwz19 with SMTP id 19so506803bwz.16 for ; Fri, 18 Jun 2010 13:29:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:date:message-id :subject:from:to:content-type; bh=Am0vVbvXtO8xq+X7940BltYyWPbLx0V198r+3wU6RRg=; b=q5tfR2+lyLyLz+XPOb4yprh6OlAuDs5AdM6qBNf4dqB5gnclt4JYGDUk/d+AZ7HWc4 dufHb/zO92Bb2BAmhF8CGLU79FISJOMvMZUUGIPtXOney+tWhDXJftb9ibtHI/F/qoVQ hh+i4VDWn6/+m8tvgQFZA1aMmuuexFX2ABwWQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=Y39oI7KySUYl+nsIVdF8cDDDnVWax07hc7EtpyKnwK/WyUopFWCHgTuq1QrtlWCZug ZbrYdXTovF6j7XxirrCUfe0zRsANd8+X2t+htrOiWomanIKcbzsEqkVEw7ibbiOqda2J Q808PSNGUbnIlYK7iKAltvOmv8Z6uqlz0NOg8= MIME-Version: 1.0 Received: by 10.204.160.69 with SMTP id m5mr1260583bkx.70.1276892972376; Fri, 18 Jun 2010 13:29:32 -0700 (PDT) Received: by 10.204.100.69 with HTTP; Fri, 18 Jun 2010 13:29:32 -0700 (PDT) Date: Fri, 18 Jun 2010 21:29:32 +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: LF: Earth electrode loop area - I'm struggling Content-Type: multipart/alternative; boundary=0015175cbb1208e47d048953d014 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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-m237.2 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1d604b4c1bd79d56de X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --0015175cbb1208e47d048953d014 Content-Type: text/plain; charset=ISO-8859-1 Please can someone help me with the maths? I've been trying to work out my effective loop area and I cannot get sensible answers. These are the measured or estimated numbers I have: Voltage across "loop" = 24.48V rms - measured Current flowing in "loop" = 0.15A - measured ERP (from far field levels) = 50-100uW (may be less) based on -18dB S/N with M0BMU >From these figures I should be able to work out the loop area, but either my calculations are wrong or the figure is correct and the effective loop area is very very small. Help! 73s Roger G3XBM -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --0015175cbb1208e47d048953d014 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Please can someone help me with the maths? I've been trying to work ou= t my effective loop area and I cannot get sensible answers. These are the= measured or estimated numbers I have:

Voltage across "loop&qu= ot;=A0 =3D 24.48V rms=A0 - measured
Current flowing in "loop" =3D 0.15A - measured
ERP (from far= field levels) =3D 50-100uW (may be less) based on -18dB S/N with M0BMU
From these figures I should be able to work out the loo= p area, but either my calculations are wrong or the figure is correct and= the effective loop area is very very small.

Help!

73s
Roger G3XBM

--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--0015175cbb1208e47d048953d014--