Return-Path: Received: from mtain-mi12.r1000.mx.aol.com (mtain-mi12.r1000.mail.aol.com [172.21.131.170]) by air-df06.mail.aol.com (v129.4) with ESMTP id MAILINDF062-5ef74c656ef214b; Fri, 13 Aug 2010 12:12:34 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mi12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 405653800006F; Fri, 13 Aug 2010 12:12:32 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ojwqw-0003wc-9t for rs_out_1@blacksheep.org; Fri, 13 Aug 2010 17:11:30 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Ojwqv-0003wT-RX for rsgb_lf_group@blacksheep.org; Fri, 13 Aug 2010 17:11:29 +0100 Received: from blu0-omc1-s1.blu0.hotmail.com ([65.55.116.12]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Ojwqv-0001Sh-3v for rsgb_lf_group@blacksheep.org; Fri, 13 Aug 2010 17:11:29 +0100 Received: from BLU146-W26 ([65.55.116.7]) by blu0-omc1-s1.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 13 Aug 2010 09:11:20 -0700 Message-ID: X-Originating-IP: [138.32.32.166] From: Laurence KL7UK To: Date: Fri, 13 Aug 2010 08:11:20 -0800 Importance: Normal In-Reply-To: References: ,<4C6566E7.5090207@charter.net>, MIME-Version: 1.0 X-OriginalArrivalTime: 13 Aug 2010 16:11:20.0969 (UTC) FILETIME=[2B201F90:01CB3B02] X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001 Content-Type: multipart/alternative; boundary="_942480cb-540b-4ef8-8bd3-69926d1088fd_" Subject: RE: LF: A question about loops for 136 and 500kHz TX 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=FORGED_HOTMAIL_RCVD, 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-sid: 3039400cded44c656ef05788 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --_942480cb-540b-4ef8-8bd3-69926d1088fd_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Got to say Id keep it off and away from any earthed or partially losses ob= ject as it does affect the Q etc, and if the fence gets wet it will detune= more - =20 8ft was the minimum height I used - just out of reach of the "animals" in= Oklahoma and it would be 10ft in Alaska cos of the Moose...I used multipa= ralled loops to reduce the R but the loop conductors all told probably wei= ghed 220 pounds. =20 As others have said - Im not sure of the power but there still can be a co= uple of Kv on the loop (at 1Kw say) and with the very high currents (30-50= A) involved it reminds of car battery connections (or if your of my age -= bus bar connection requirements in telephone exchanges) - then add a Kv= or two. =20 =20 - with a reasonable TX "largish" Low loss loop resonanted tuning thru reso= nance with an SSB receiver will sound like a tight 1.4Khz or tighter mecha= nical filter...well at 137 it did. =20 Laurence KL7UK =20 Date: Fri, 13 Aug 2010 16:53:07 +0100 From: rogerlapthorn@gmail.com To: rsgb_lf_group@blacksheep.org Subject: Re: LF: A question about loops for 136 and 500kHz TX Wow - not bad feed back in a few minutes! Thanks everyone for chipping in= with ideas and links. I guess my question was prompted by the results recently with the earth el= ectrode antenna with the ground actually forming part of a loop antenna.= The logical extension was to elevate the loop but leave the bottom runnin= g along the ground (in a wire rather than relying on the soil for the retu= rn path with its resistive losses). If I may pr=E9cis the responses here, you all consider this is not a good= idea and recommend elevating the lower section a few metres. I can do thi= s, running the lower wire along the top of the wooden garden fence (OK?)= .=20 73s Roger G3XBM =3D --_942480cb-540b-4ef8-8bd3-69926d1088fd_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Got to say Id keep it off and away from any earthed or partially losses ob= ject as it does affect the Q etc, and if the fence gets wet it will detune= more -
 
 8ft was the minimum height I used - just out of reach of= the "animals" in Oklahoma and it would be 10ft in Alaska cos of the= Moose...I used multiparalled loops to reduce the R but the loop cond= uctors all told probably weighed 220 pounds.
 
As others have said - Im not sure of the power but there still can be a co= uple of Kv on the loop (at 1Kw say) and with the very high currents (30-50= A) involved it reminds of car battery connections (or if your of my= age - bus bar connection requirements in telephone exchanges) - then add= a Kv or two.
 
 
- with a reasonable TX "largish" Low loss loop resonanted tuning thru= resonance with an SSB receiver will sound like a tight 1.4Khz or tig= hter mechanical filter...well at 137 it did.
 
Laurence KL7UK

 
Date: Fri, 13 Aug 2010 16:53:07 +0100
From: rogerlapthorn@gmail.com
= To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: A question about loop= s for 136 and 500kHz TX

Wow - not bad feed back in a few minutes!= Thanks everyone for chipping in with ideas and links.

I guess my= question was prompted by the results recently with the earth electrode an= tenna with the ground actually forming part of a loop antenna. The= logical extension was to elevate the loop but leave the bottom running along the ground (in a wire rather than relying on the soil for the= return path with its resistive losses).

If I may pr=E9cis the resp= onses here, you all consider this is not a good idea and recommend= elevating the lower section a few metres. I can do this, running the lowe= r wire along the top of the wooden garden fence (OK?) .

73s
Rog= er G3XBM

=3D --_942480cb-540b-4ef8-8bd3-69926d1088fd_--