Return-Path: Received: from mtain-mi09.r1000.mx.aol.com (mtain-mi09.r1000.mail.aol.com [172.21.131.167]) by air-ma08.mail.aol.com (v129.4) with ESMTP id MAILINMA084-b5334c65654b1f0; Fri, 13 Aug 2010 11:31:23 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mi09.r1000.mx.aol.com (Internet Inbound) with ESMTP id A1723380000FE; Fri, 13 Aug 2010 11:31:21 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OjwDA-0003Jt-3w for rs_out_1@blacksheep.org; Fri, 13 Aug 2010 16:30:24 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OjwD9-0003Jk-JU for rsgb_lf_group@blacksheep.org; Fri, 13 Aug 2010 16:30:23 +0100 Received: from mail-qy0-f178.google.com ([209.85.216.178]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OjwD7-0000zJ-Mw for rsgb_lf_group@blacksheep.org; Fri, 13 Aug 2010 16:30:23 +0100 Received: by qyk30 with SMTP id 30so1195395qyk.16 for ; Fri, 13 Aug 2010 08:30:15 -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=4bxacgZc3cbiDMLJRmeNZkPSUELm+BNypTqH6mdfbOs=; b=G3dWkrMGlJYjyEZjkgRXTymU7/9NKhnETTP2HDtleR4VETiBcaZdYTKH9BSTyRn9RE uC5JLh3ERAdgKSGB244OHkrj+elPB7ag9121VWl3H4lGszziA1SC9Baeml7XGY/1U5lh bUX3t0h3L8RurZHKiZv9QtmK+YdUDNfeMy3jA= 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=RZavYcspSWfqzjBBtOcMF1x1VxARZFNI6puNp34wsteLQXdczSF0Klpt9NwOd2Dpst 0Gk8swhyChYNd1Zy5+C63G7FLjEt4giBBue7PkEIYGFzua7V1TZfDP+Dg6EuAnXtrsGS xls0d+QQj9kuHXaltHgRvFx+gKL8g889JMp3M= MIME-Version: 1.0 Received: by 10.229.11.18 with SMTP id r18mr1295224qcr.281.1281713414259; Fri, 13 Aug 2010 08:30:14 -0700 (PDT) Received: by 10.229.129.138 with HTTP; Fri, 13 Aug 2010 08:30:14 -0700 (PDT) In-Reply-To: <000d01cb3afb$9d1236d0$4001a8c0@lark> References: <000d01cb3afb$9d1236d0$4001a8c0@lark> Date: Fri, 13 Aug 2010 11:30:14 -0400 Message-ID: From: Warren Ziegler 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: A question about loops for 136 and 500kHz TX Content-Type: multipart/alternative; boundary=0016364ed0a4c2c8fb048db62853 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-m205.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039400cded14c6565495be1 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --0016364ed0a4c2c8fb048db62853 Content-Type: text/plain; charset=ISO-8859-1 G3YXM ran a loop from a portable QTH in Scotland in 2006 http://www.wireless.org.uk/loopy.htm -- 73 Warren K2ORS WD2XGJ WD2XSH/23 WE2XEB/2 WE2XGR/1 On Fri, Aug 13, 2010 at 11:24 AM, Alan Melia wrote: > Hi Roger if it is laid on the ground the currnet will couple to the lossy > ground increasing the aerial loos and reducing the already low efficiency > of > the loop. You might search for articles by Bill Ashlock who has done a lot > of systematic experiments with TX loops in the States. I dont recall anyone > bar Dave Sargent using a loop in the UK. > > Alan G3NYK > > > > ----- Original Message ----- > From: "Roger Lapthorn" > To: > Sent: Friday, August 13, 2010 4:08 PM > Subject: LF: A question about loops for 136 and 500kHz TX > > > > Having considered the antenna options for my small garden, I'm going to > > erect a TX loop antenna rather than a Marconi vertical for 136kHz: the > > earthing issues are removed and it is easier to build a capacitor > selection > > box (to tune and match the loop) than wind a huge loading coil and match > it. > > I've seen some of the webpages dealing with these and understand > basically > > what is needed (large loop area, thick wire, capacitor match-box, dealing > > with high RF currents, etc). I understand the loop will have > directionality > > and nulls. > > > > My question is this. *Is there any reason why the bottom of the loop > cannot > > be laid along the ground rather than elevated a few metres?* Most designs > > show the bottom elevated a bit, but if laid on the soil I could use thick > > coax or multiple wires for part of the loop so reducing the loop > resistance. > > > > > > Views appreciated, although it may be a case of "suck it and see". > > > > 73s > > Roger G3XBM > > > > -- > > http://g3xbm-qrp.blogspot.com/ > > http://www.g3xbm.co.uk > > http://www.youtube.com/user/g3xbm > > G3XBM GQRP 1678 ISWL G11088 > > > > > --0016364ed0a4c2c8fb048db62853 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable G3YXM ran a loop from a portable QTH in Scotland in 2006
http://www.wireless.org.uk/loopy.htm

--
73 Warren K2ORS
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 WD2XGJ=
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 WD2XSH/23
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 WE2XEB/2
=A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 WE2XGR/1



On Fri, Aug 13, 201= 0 at 11:24 AM, Alan Melia <alan.melia@btinternet.com> wrote:
Hi Roger if it= is laid on the ground the currnet will couple to the lossy
ground increasing the aerial loos and reducing the already low efficiency= of
the loop. You might search for articles by Bill Ashlock who has done a lot=
of systematic experiments with TX loops in the States. I dont recall anyon= e
bar Dave Sargent using a loop in the UK.

Alan G3NYK



----- Original Message -----
From: "Roger Lapthorn" <rogerlapthorn@gmail.com>
To: <rsgb_lf_group@blac= ksheep.org>
Sent: Friday, August 13, 2010 4:08 PM
Subject: LF: A question about loops for 136 and 500kHz TX


> Having considered the antenna options for my small garden, I'm go= ing to
> erect a TX loop antenna rather than a Marconi vertical for 136kHz: th= e
> earthing issues are removed and it is easier to build a capacitor
selection
> box (to tune and match the loop) than wind a huge loading coil and ma= tch
it.
> I've seen some of the webpages dealing with these and understand= basically
> what is needed (large loop area, thick wire, capacitor match-box, dea= ling
> with high RF currents, etc). I understand the loop will have
directionality
> and nulls.
>
> My question is this. *Is there any reason why the bottom of the loop<= br> cannot
> be laid along the ground rather than elevated a few metres?* Most des= igns
> show the bottom elevated a bit, but if laid on the soil I could use= thick
> coax or multiple wires for part of the loop so reducing the loop
resistance.
>
>
> Views appreciated, although it may be a case of "suck it and see= ".
>
> 73s
> Roger G3XBM
>
> --
> http://g= 3xbm-qrp.blogspot.com/
> http://www.g3xbm= .co.uk
> http:= //www.youtube.com/user/g3xbm
> G3XBM =A0 GQRP 1678 =A0 =A0ISWL G11088
>





=A0
--0016364ed0a4c2c8fb048db62853--