Return-Path: Received: (qmail 71101 invoked from network); 30 Mar 2005 07:08:57 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore04.plus.net with SMTP; 30 Mar 2005 07:08:57 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1DGXK2-0000Ek-Jp for dave@picks.force9.co.uk; Wed, 30 Mar 2005 08:09:02 +0100 Received: from [192.168.67.3] (helo=ptb-mxcore03.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1DGXK2-0000Eh-HR for dave@picks.force9.co.uk; Wed, 30 Mar 2005 08:09:02 +0100 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1DGXMg-0003Un-0G for dave@picks.force9.co.uk; Wed, 30 Mar 2005 08:11:46 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DGXJO-0007EN-46 for rs_out_1@blacksheep.org; Wed, 30 Mar 2005 08:08:22 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DGXJN-0007EE-Hy for rsgb_lf_group@blacksheep.org; Wed, 30 Mar 2005 08:08:21 +0100 Received: from one.surfree.co.uk ([195.80.0.234]) by relay.thorcom.net with esmtp (Exim 4.43) id 1DGXJM-00073P-5j for rsgb_lf_group@blacksheep.org; Wed, 30 Mar 2005 08:08:21 +0100 Received: from standalone ([212.248.140.40]) by one.surfree.co.uk (8.9.3/8.9.3) with SMTP id JAA32342 for ; Wed, 30 Mar 2005 09:08:46 +0100 Message-ID: <002b01c534f6$ecac9660$288cf8d4@standalone> From: "Andy" To: rsgb_lf_group@blacksheep.org Date: Wed, 30 Mar 2005 08:05:56 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 X-SPF-Result: relay.thorcom.net: 195.80.0.234 is neither permitted nor denied by domain of southsurf.com X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: Re: low long wire as TX-antenna??? Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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-Spam-Filtered: by PlusNet SpamCORE (v3.00) I think you can go a bit further with that Alan. If you have a really long, low, wire then the current is returned via the ground, penetrating down to skin depths. The result is a big loop, with the dimensions of (effective) skin depth * length of wire. So resulting in vertical polarisation. This was (still is ??) the type of antenna used by the US at ULF (67 Hz, 81 Hz ???) for their submarine communications. Wires that look like overhead telephone cables disappearing for hundreds of km into the distance! If you want a bit of fun reading conspiracy theorists ranting, do a Google search for "ULF" to find out about the government's mind numbing radiation experiments ! Andy G4JNT >hear some of the pundits sharpening their pencils....it is actually not that >simple, as the ground level is not the level of the "Earth-plate" you must >take into effect the skin depth of the ground at this frequency. This is >dependent upon the frequency and nature of the soil. Thus at ELF (< 3kHz), >the type of antenna you think of will work quite well (compared with >anything else) the skin depth is proportional to the frequency but the >radiation resistance is proportional to the (frequency)^2. I think you said >you ground was poor, sandy. That would work to some extent if there were no >surrounding lossy "environment"....like trees shrubs and houses. I suspect >this is why the VK antenna across the valley that Bob describes works so