Return-Path: Received: (qmail 20999 invoked from network); 21 Oct 2002 19:28:23 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 21 Oct 2002 19:28:23 -0000 Received: (qmail 23567 invoked from network); 21 Oct 2002 19:27:39 -0000 Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 21 Oct 2002 19:27:39 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 183iCT-0004tg-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 21 Oct 2002 20:26:53 +0100 Received: from [210.86.15.147] (helo=mta204-rme.xtra.co.nz) by post.thorcom.com with esmtp (Exim 4.10) id 183iCR-0004tX-00 for rsgb_lf_group@blacksheep.org; Mon, 21 Oct 2002 20:26:52 +0100 Received: from mta1-rme.xtra.co.nz ([210.86.15.142]) by mta204-rme.xtra.co.nz with ESMTP id <20021021192619.GZBA3898.mta204-rme.xtra.co.nz@mta1-rme.xtra.co.nz> for ; Tue, 22 Oct 2002 08:26:19 +1300 Received: from xtr743187 ([210.54.78.130]) by mta1-rme.xtra.co.nz with SMTP id <20021021192618.PYZV1326.mta1-rme.xtra.co.nz@xtr743187> for ; Tue, 22 Oct 2002 08:26:18 +1300 Message-ID: <003101c27937$bb771160$824e36d2@xtr743187> From: "Vernall" To: rsgb_lf_group@blacksheep.org References: <149.e0083f.2ae57a4a@aol.com> Date: Tue, 22 Oct 2002 08:25:39 +1300 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2919.6600 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: Re: Ant Questions Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-0.3 required=5.0tests=QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_00_01, USER_AGENT_OEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Steve, > I'd arrived at. Does the current really taper > away to zero at the open ends or is that effect swamped by ground capacitance > when it's only 0.5% of a wavelength above ground? The RF current at the open end of any wire is the vector sum of incident and reflected energy. Current "cancels" as that reflection co-efficient is nominally "-1", whereas voltage doubles, as that reflection co-efficient is nominally "+1". That is the basic mechanism for a "standing wave". Specific voltage and/or current distribution is influenced by the antenna specific environment, but it would generally not be "swamped" by the likes of ground capacitance, as wire segments "connecting to themselves" presents a much lower impedance. Mention of "displacement current" would probably be a red herring ..... 73, Bob ZL2CA