Return-Path: Received: (qmail 21145 invoked from network); 12 Dec 2002 22:15:14 -0000 Received: from netmail02.services.quay.plus.net (212.159.14.221) by mailstore with SMTP; 12 Dec 2002 22:15:14 -0000 Received: (qmail 5274 invoked by uid 10001); 12 Dec 2002 22:14:45 -0000 Received: from post.thorcom.com (193.82.116.70) by netmail02.services.quay.plus.net with SMTP; 12 Dec 2002 22:14:45 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18Mbar-0004WX-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 12 Dec 2002 22:14:09 +0000 Received: from [194.73.73.111] (helo=gadolinium.btinternet.com) by post.thorcom.com with esmtp (Exim 4.10) id 18Mbar-0004WO-00 for rsgb_lf_group@blacksheep.org; Thu, 12 Dec 2002 22:14:09 +0000 Received: from host213-123-48-161.in-addr.btopenworld.com ([213.123.48.161] helo=main) by gadolinium.btinternet.com with smtp (Exim 3.22 #16) id 18Mbaq-0003zn-00 for rsgb_lf_group@blacksheep.org; Thu, 12 Dec 2002 22:14:08 +0000 Message-ID: <001601c2a22b$b21e0340$a1307bd5@main> From: "Alan Melia" To: "LF-Group" Date: Thu, 12 Dec 2002 22:13:21 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: re Antenna tests Content-Type: text/plain; charset=Windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=1.0 required=5.0tests=SPAM_PHRASE_02_03,USER_AGENT_OEversion=2.42 X-Spam-Level: * Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi all, Finbar EI0CF measured one of our spiral evolutions under several different weather conditions. Finbar's site is right on the shore of Trawbreager Bay so he has sea water close at hand. When we had increased the top load the ground loss was ultimately reduced to about 20 ohms in normal (dry) conditions. As one might expect when it was actually raining, a high loss resistance was measured. (There would have been a water film over the plastic coated wire used. ) This loss reduced immediately the rain stopped, but the loss resistance still remained about twice the normal "dry" value. Even long after the rain has ceased the loss stayed high whilst the ground was still freshly wet. The measured loss did not return to normal for about 24 hours afterwards. I assume fresh rainwater has a high permittivity and also a high resistance. Over time salts will disolve into the wet mass reducing its resistivity. These measurements are still in my file as I had not yet decided how to explain the results. However in view of "corroborating" evidence I will see if I can pull then together. All measurements were done using a simple RF bridge described on my web site. Cheers de Alan G3NYK alan.melia@btinternet.com http://www.alan.melia.btinternet.co.uk