Return-Path: Received: (qmail 25501 invoked from network); 13 May 2001 11:39:32 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 13 May 2001 11:39:32 -0000 Received: (qmail 4426 invoked from network); 13 May 2001 11:39:00 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 13 May 2001 11:39:00 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14yu7n-0002AA-00 for rsgb_lf_group-outgoing@blacksheep.org; Sun, 13 May 2001 12:33:23 +0100 Received: from rubellite.lion-access.net ([212.19.217.4]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14yu7m-0002A5-00 for rsgb_lf_group@blacksheep.org; Sun, 13 May 2001 12:33:22 +0100 Received: from w8k3f0 (1Cust238.tnt29.rtm1.nl.uu.net [213.116.152.238]) by rubellite.lion-access.net (I-Lab) with SMTP id 4738C2D69 for ; Sun, 13 May 2001 11:32:28 +0000 (GMT) Message-ID: <000c01c0dba0$dc6daf40$ee9874d5@w8k3f0> From: "Dick Rollema" To: rsgb_lf_group@blacksheep.org References: <000801c0db1d$56d4e020$1a9901d4@g4jnt> Subject: Re: LF: Measurement of antenna current Date: Sun, 13 May 2001 13:35:08 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2314.1300 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: To All from PA0SE Andy, G4JNT, wrote as a comment on GW4ALG's experiment using aluminum kitchen foil as a grouind screen under his loading coil: > Aluminium kitchen foil is much thinner than the skin depth at these > frequencies, so you are getting nowhere near the full screening effect. It that so? I thought it means that the current density over the thickness of the foil is almost uniform with result that AC and DC resistance are almost equal. But even with the thin foil that resistance will be so much smaller than the resistance via the real earth that I expect almost all capacitive current from the coil is captured by the foil. Am I wrong? 73, Dick, PA0SE