Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mg01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0274E38000097; Wed, 9 Jan 2013 13:42:23 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Tt0Zo-0007Df-Qm for rs_out_1@blacksheep.org; Wed, 09 Jan 2013 18:40:36 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Tt0Zn-0007DW-Vn for rsgb_lf_group@blacksheep.org; Wed, 09 Jan 2013 18:40:35 +0000 Received: from mail-qa0-f52.google.com ([209.85.216.52]) by relay1.thorcom.net with esmtps (TLSv1:RC4-SHA:128) (Exim 4.77) (envelope-from ) id 1Tt0Zk-0007c9-S4 for rsgb_lf_group@blacksheep.org; Wed, 09 Jan 2013 18:40:34 +0000 Received: by mail-qa0-f52.google.com with SMTP id d13so939754qak.11 for ; Wed, 09 Jan 2013 10:40:10 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=SsE288DIgny9UefbD1YVrTTt+kSR12mefMmmqqsrjWs=; b=mB5D6Ds3IN6PLnspYkKcPc0IvEskgzbmES+UzONq140szg3MP70aYGK2sD2lb+KzB4 ifThIx59+QASEn4rPWD5TjnTfDQiKEW4o4xn5bMm+9WASi6Hiq0amONPL7FqCj069vAo WIXTruhBgB87XYTuLbs/um0mxZ/EBPvVAE3SRICTKw0O0w1O40RIj+phj+araBo6dj2F 2WFw2pEmUsFpnayrHzYWE3SC1TLKBilNRCMOvHkbSu8xlz0sfgumQYGJ2hiiA69ZIxse is2yaFu5nJMZ6s3D5KBeUX8/Nb/S1yh7Hq4Sn+NYW2EfgbiCz9xps7mJ0CORAvr6s/Ks Yqsw== MIME-Version: 1.0 Received: by 10.229.175.29 with SMTP id v29mr12895312qcz.103.1357756810052; Wed, 09 Jan 2013 10:40:10 -0800 (PST) Received: by 10.229.156.18 with HTTP; Wed, 9 Jan 2013 10:40:09 -0800 (PST) In-Reply-To: <7E7DFBB4D102A04DB5ADC88D66628A4A0FB68393@ICTS-S-MBX5.luna.kuleuven.be> References: <3401C753-302E-4621-9137-45B9A216D17F@gmail.com> <7E7DFBB4D102A04DB5ADC88D66628A4A0FB68393@ICTS-S-MBX5.luna.kuleuven.be> Date: Wed, 9 Jan 2013 18:40:09 +0000 Message-ID: From: Roger Lapthorn To: "rsgb_lf_group@blacksheep.org" X-Spam-Score: -0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Rik, This data will be available in the next few hours: a set of measurements today with just the wire on the ground to compare with the tests over the last few days with the wire elevated to 1.5m for part of its length (about half its length). [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.216.52 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rogerlapthorn[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_OBFUSCATE_05_10 BODY: Message is 5% to 10% HTML obfuscation 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 62881a307367ee77b931f40221fe80e6 Subject: Re: LF: RE: [rsgb_lf_group] Earth electrode antenna with wire at zero height (WSPR 472kHz) Content-Type: multipart/alternative; boundary=0016e6d375a65ac4cc04d2df6412 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_40_50,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-SCOLL-AUTHENTICATION: mtain-mg01.r1000.mx.aol.com ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d60c950edba0f264d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --0016e6d375a65ac4cc04d2df6412 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Rik, This data will be available in the next few hours: a set of measurements today with just the wire on the ground to compare with the tests over the last few days with the wire elevated to 1.5m for part of its length (about half its length). Give me a little time and we'll see what the numbers produce: certainly the many decent spots this afternoon suggest that underground loop must be a reasonable size. 73s Roger G3XBM On 9 January 2013 16:45, Rik Strobbe wrote: > Hello Roger, > > > > assuming that the underground antenna behaves like a loop: > > For a classic loop area of the loop and the current flow are well defined= (the current > goes through the wire =3D circumference of the loop). > > This is not the case for the underground antenna, there will be a current > flow through an area or even a volume. > > But one could define the virtual area of the underground antenna as > the area of a classic loop that procudes the same ERP (with the sameanten= na current) > as the underground antenna. > > But how to determine this virtual loop area? > > Suggestion: > > You can measure the relative ERP of your underground loop (at a givenante= nna current > ) using daytime WSPR and some local RX station (daytime and local will > rule out any propagation changes). > > Let's define the virtual area of the underground antenna as A1 (m^2) and > the relative ERP as P1 (=3D dB values from WSPR). > > Next you could raise the wire, increasing the loop area by a know value A= 2 > ). Again measure the relative ERP P2 (as before, using the same WSPR RXst= ations at daytime > ). > > Now the total loop area is A1+A2, where we know A2 (the above groundpart)= but > not A1 (the virtual underground part). > > A1 can be calculated: > > At a constant antenna current the ERP will be proportional to the square > of the loop area. > > So P1 is proportional to A1^2 and P2 is proportional to (A1+A2)^2. > > Or: P2/P1 =3D (A1+A2)^2/A1^2 =3D (A1^2+2*A1*A2+A2^2)/A1^2 > > And after some more math: > > A1 =3D ((1+sqrt(P2/P1))/((P2/P1)-1))*A2. > > So based on the ERP increase (P2/P1) and the above ground area (A2) of > the loop the virtual area (A1) of the "submerged" part can be calculated. > > If this is done for some different heights of the wire (=3D different val= uesof A2 > ) one would have an indication if this theory is valid (the outcome of > the virual area should be more or less the same). > > > > 73, Rik ON7YD - OR7T > > > > > ------------------------------ > *Van:* rsgb_lf_group@yahoogroups.co.uk [rsgb_lf_group@yahoogroups.co.uk] > namens Roger Lapthorn [rogerlapthorn@gmail.com] > *Verzonden:* woensdag 9 januari 2013 15:54 > *To:* rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk > *Onderwerp:* [rsgb_lf_group] Earth electrode antenna with wire at zero > height (WSPR 472kHz) > > > > Ok, so as the final instalment of this test I have now got the wires from > the earth rods coming to the transverter just resting on the wet grass > (what was elevated by 1.5m is now zero). It seems to work best just feedi= ng > the transverter straight into the rods without matching suggesting low > reactance and near 50 ohms. > > I'm still getting decent reports! So, it confirms the "loop in the ground= " > theory, or it is acting as some bizarre E field antenna. > > Will again leave it running overnight to get a decent number of spots but > already I think we have an answer. > > What I can try next - is this ever going to end!? - is elevate the loop > part "in the air" to much greater height (about 9m to match the top of th= e > Marconi I just took down) and see how much improvement I get. More in the > air implies greater loop area so more signal. Just how much will indicate > how much of the loop's effective area is in the soil/rock. > > WSPR spots please folks. > > 73s > Roger G3XBM > __._,_.___ > Reply to sender| Re= ply > to group| Re= ply > via web post| Start > a new topic > Messages in this topic( > 1) > Recent Activity: > > - New Members > 8 > - New Photos > 1 > - New Links > 1 > > Visit Your Group > [image: Yahoo! Groups] > Switch to: Text-Only, > Daily Digest=95 > Unsubscribe=95 Terms > of Use > . > > __,_._,___ > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk https://sites.google.com/site/sub9khz/ http://qss2.blogspot.com/ --0016e6d375a65ac4cc04d2df6412 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Rik,

This data will be av= ailable in the next few hours: a set of measurements today with just the wi= re on the ground to compare with the tests over the last few days with the = wire elevated to 1.5m for part of its length (about half its length).

Give me a little time and we'll see what the numbers produce:= certainly the many decent spots this afternoon suggest that underground lo= op must be a reasonable size.

73s
Roger G3XBM


On 9 Ja= nuary 2013 16:45, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be&g= t; wrote:

Hello=A0Roger= ,

=A0

assuming=A0th= at the underground antenna=A0behaves=A0like<= /a> a loop:

For a=A0classic loop=A0area of the loop and the=A0cu= rrent=A0flow=A0are=A0well=A0defin= ed (the=A0current=A0goes=A0throug= h the=A0wire =3D=A0circ= umference of the loop).

This=A0is=A0not the case=A0fo= r=A0the underground antenna,=A0there=A0will=A0be a= =A0current=A0flow=A0through=A0an<= a>=A0area=A0or even a volume.=

But=A0one=A0could=A0define=A0the=A0virtual=A0area of the underground antenna as the=A0area of a classic loop= =A0that=A0procudes the=A0same ERP= (with the=A0same antenna current= ) as the underground antenna.

But=A0how to=A0determine=A0this=A0virtual loop area?

Suggestion:

You=A0can=A0measure= the=A0relative ERP of=A0your underground loop (at a=A0given a= ntenna current)=A0using=A0daytime= =A0WSPR and=A0some=A0local=A0RX station (daytime and=A0local=A0wil= l=A0rule out=A0any=A0propagation changes)= .

Let's=A0define the=A0virt= ual=A0area of the underground antenna as=A0A1 (m^2) and the=A0relative<= a> ERP as=A0P1 (=3D dB=A0values=A0fr= om WSPR).

Next=A0you=A0could<= /a>=A0raise the wire,=A0increasing the loop=A0area=A0by a=A0know=A0value A2).=A0Again=A0measure the=A0relative<= /a> ERP=A0P2 (as before,=A0using<= a> the=A0same=A0WSPR=A0RX stations = at daytime).

Now=A0the=A0total loop=A0area= is A1+A2,=A0where we=A0know=A0A2 (the=A0above=A0gr= ound part)=A0but=A0not=A0A1 (the=A0virtual underground part).

A1=A0can=A0be c= alculated:

At a constant antenna=A0current the ERP=A0will= =A0be=A0proportional to the squar= e of the loop area.

So=A0P1 is=A0proportional<= /a> to A1^2 and=A0P2 is=A0proportional to (A1+A2)^2.

Or: P2/P1 =3D (A1+A2)^2/A1^2 =3D (A1^2+2*A1*A2+A2^2)/A1^2

And=A0after=A0some more math<= /a>:

A1=A0=3D ((1+sqrt(P2/P1))/((P= 2/P1)-1))*A2.

So=A0based=A0on= the ERP=A0increase (P2/P1) and the=A0above=A0ground=A0area= (A2) of the loop the=A0virtual=A0area (A1) of the "submerged" part=A0= can=A0be calculated.

If=A0this is=A0done= =A0for=A0some different=A0heights of the=A0wire (=3D differe= nt=A0values of A2)=A0one=A0would<= a> have=A0an=A0indication=A0if=A0this=A0theory is=A0valid (the=A0outcome of the=A0virual=A0area=A0should=A0be more=A0or=A0l= ess the same).

=A0

73, Rik=A0=A0ON7YD -=A0OR7T=A0

=A0

=A0

Van= : = rsgb_lf_group@yahoogroups.co.uk [rsgb_lf_group@yahoogroups.co.uk] namens = Roger Lapthorn [rogerlapthorn@gmail.com]
Verzonden: woensdag 9 januari 2013 15:54
To: rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk
Onderwerp: [rsgb_lf_group] Earth electrode antenna with wire at zero= height (WSPR 472kHz)

=A0

Ok, so as the final instalment of this test I have now got the wires fro= m the earth rods coming to the transverter just resting on the wet grass (w= hat was elevated by 1.5m is now zero). It seems to work best just feeding t= he transverter straight into the rods without matching suggesting low reactance and near 50 ohms.

I'm still getting decent reports! So, it confirms the "loop in the= ground" theory, or it is acting as some bizarre E field antenna.

Will again leave it running overnight to get a decent number of spots but a= lready I think we have an answer.

What I can try next - is this ever going to end!? - is elevate the loop par= t "in the air" to much greater height (about 9m to match the top = of the Marconi I just took down) and see how much improvement I get. More i= n the air implies greater loop area so more signal. Just how much will indicate how much of the loop's effective a= rea is in the soil/rock.

WSPR spots please folks.

73s
Roger G3XBM

__._,_.___
.
=A0
__,_._,___



--
=A0http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/
http://qss2.blogspot.com/

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