Return-Path: Received: from mtain-mb06.r1000.mx.aol.com (mtain-mb06.r1000.mx.aol.com [172.29.96.26]) by air-dd04.mail.aol.com (v129.4) with ESMTP id MAILINDD041-860a4c1be8db2a5; Fri, 18 Jun 2010 17:44:59 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mb06.r1000.mx.aol.com (Internet Inbound) with ESMTP id E4B4E3800008B; Fri, 18 Jun 2010 17:44:56 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OPjMC-0007XM-D7 for rs_out_1@blacksheep.org; Fri, 18 Jun 2010 22:44:12 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OPjMB-0007XD-U6 for rsgb_lf_group@blacksheep.org; Fri, 18 Jun 2010 22:44:11 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OPjM8-0002fU-Td for rsgb_lf_group@blacksheep.org; Fri, 18 Jun 2010 22:44:11 +0100 Received: by bwz19 with SMTP id 19so531861bwz.16 for ; Fri, 18 Jun 2010 14:44:08 -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=t098qVIRuhZEmOAJlDfu3dWeoJKgdll1UF+9MSaPSCw=; b=VOjW8EfKmcPF1GPoEJt6ksflkpNDj8+gm3wtv/++T5u0WFXh79sWB7xPdPhKo36Z/k lGCspcf7sxB2Xmw3K6/36QFbDz8jwt0TFWtISynYFmm1ABiUcwQIVoLRGJIPZqeIiSs5 xiiYUya7hXArEQ5O7mtdF/5i/xbqu++rpmjrs= 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=VCOhwi0R7zN9X4YaFw0HRtZ2G3ul2DocG4f8suS/Zq4NpLy8SZy4c+D2yGumqD4ovL ukgEeezwl/exhZZznuSjTb61xL7INficHZDrbKmEfnl2sRRrbTkvsM7z1g/MYYOvMOPQ 0i6lLSIjqlx35UVlspK+EK+lteB1Yl0TH6+ZI= MIME-Version: 1.0 Received: by 10.204.161.201 with SMTP id s9mr1322661bkx.19.1276897448332; Fri, 18 Jun 2010 14:44:08 -0700 (PDT) Received: by 10.204.100.69 with HTTP; Fri, 18 Jun 2010 14:44:08 -0700 (PDT) In-Reply-To: <002001cb0f2d$8f03d890$4001a8c0@lark> References: <002001cb0f2d$8f03d890$4001a8c0@lark> Date: Fri, 18 Jun 2010 22:44:08 +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: Earth electrode loop area - I'm struggling Content-Type: multipart/alternative; boundary=000325558e4ed28f07048954da5b 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-AUTHENTICATION: mail_rly_antispam_dkim-d240.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d601a4c1be8d825df X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --000325558e4ed28f07048954da5b Content-Type: text/plain; charset=ISO-8859-1 Alan - see Rik's figures. Jim is not far off the line of fire from the "loop", maybe 20 degrees off at most. 73s Roger G3XBM On 18 June 2010 22:31, Alan Melia wrote: > Hi Roger A quick bit a fudging suggests about 6 (to 12)sq m. equivalent > (not > guaranteed correct :-)) ). How does that align with your figs? It suggests > your aerial (loop) is not in the best > direction for him, or possibly you have a skin of good conductive ground > over the chalk, so you are not penertrating into the ground so much.. > > What is your distance from Jim?? > > Alan > > ----- Original Message ----- > From: "Roger Lapthorn" > To: > Sent: Friday, June 18, 2010 9:29 PM > Subject: LF: Earth electrode loop area - I'm struggling > > > > 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 > > > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --000325558e4ed28f07048954da5b Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Alan - see Rik's figures.

Jim is not far off the line of fire= from the "loop", maybe 20 degrees off at most.

73s
R= oger G3XBM

On 18 June 2010 22:31, Alan= Melia <= alan.melia@btinternet.com> wrote:
Hi Roger A quic= k bit a fudging suggests about 6 (to 12)sq m. equivalent (not
guaranteed correct :-)) =A0). How does that align with your figs? It sugge= sts
your aerial (loop) is not in the best
direction for him, or possibly you have a skin of good conductive ground over the chalk, so you are not penertrating into the ground so much..

What is your distance from Jim??

Alan

----- Original Message -----
From: "Roger Lapthorn" <rogerlapthorn@gmail.com>
To: <rsgb_lf_group@blac= ksheep.org>
Sent: Friday, June 18, 2010 9:29 PM
Subject: LF: Earth electrode loop area - I'm struggling


> Please can someone help me with the maths? I've been trying to wo= rk out my
> effective loop area and I cannot get sensible answers. These are the<= br> > measured or estimated numbers I have:
>
> Voltage across "loop" =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 loop area, but ei= ther
my
> calculations are wrong or the figure is correct and the effective loo= p
area
> is very very small.
>
> Help!
>
> 73s
> Roger G3XBM
>
> --
> http://g= 3xbm-qrp.blogspot.com/
> http://www.g3xbm= .co.uk
> http:= //www.youtube.com/user/g3xbm
> G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
>





--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--000325558e4ed28f07048954da5b--